From 2883229309a13760296abc91ac5f64f3dffc4801 Mon Sep 17 00:00:00 2001 From: Stanimir Varbanov Date: Tue, 15 Oct 2013 17:11:17 +0300 Subject: ARM: DT: msm: Add Qualcomm's PRNG driver binding document This adds Qualcomm PRNG driver device tree binding documentation to use as an example in dts trees. Signed-off-by: Stanimir Varbanov Reviewed-by: Stephen Boyd Signed-off-by: Herbert Xu --- Documentation/devicetree/bindings/rng/qcom,prng.txt | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) create mode 100644 Documentation/devicetree/bindings/rng/qcom,prng.txt (limited to 'Documentation') diff --git a/Documentation/devicetree/bindings/rng/qcom,prng.txt b/Documentation/devicetree/bindings/rng/qcom,prng.txt new file mode 100644 index 000000000000..8e5853c2879b --- /dev/null +++ b/Documentation/devicetree/bindings/rng/qcom,prng.txt @@ -0,0 +1,17 @@ +Qualcomm MSM pseudo random number generator. + +Required properties: + +- compatible : should be "qcom,prng" +- reg : specifies base physical address and size of the registers map +- clocks : phandle to clock-controller plus clock-specifier pair +- clock-names : "core" clocks all registers, FIFO and circuits in PRNG IP block + +Example: + + rng@f9bff000 { + compatible = "qcom,prng"; + reg = <0xf9bff000 0x200>; + clocks = <&clock GCC_PRNG_AHB_CLK>; + clock-names = "core"; + }; -- cgit v1.2.3 From 4c624840ebe2d84b72e4b2ab3e7390dddf74d0a5 Mon Sep 17 00:00:00 2001 From: Tony Lindgren Date: Thu, 14 Nov 2013 15:25:07 -0800 Subject: i2c: omap: Fix missing device tree flags for omap2 As we claim to support device tree for mach-omap2, we should have the necessary flags in the driver to make it usable. Cc: linux-i2c@vger.kernel.org Acked-by: Wolfram Sang Signed-off-by: Tony Lindgren --- Documentation/devicetree/bindings/i2c/i2c-omap.txt | 3 ++- drivers/i2c/busses/i2c-omap.c | 22 ++++++++++++++++++++++ 2 files changed, 24 insertions(+), 1 deletion(-) (limited to 'Documentation') diff --git a/Documentation/devicetree/bindings/i2c/i2c-omap.txt b/Documentation/devicetree/bindings/i2c/i2c-omap.txt index 56564aa4b444..7e49839d4124 100644 --- a/Documentation/devicetree/bindings/i2c/i2c-omap.txt +++ b/Documentation/devicetree/bindings/i2c/i2c-omap.txt @@ -1,7 +1,8 @@ I2C for OMAP platforms Required properties : -- compatible : Must be "ti,omap3-i2c" or "ti,omap4-i2c" +- compatible : Must be "ti,omap2420-i2c", "ti,omap2430-i2c", "ti,omap3-i2c" + or "ti,omap4-i2c" - ti,hwmods : Must be "i2c", n being the instance number (1-based) - #address-cells = <1>; - #size-cells = <0>; diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c index 9967a6f9c2ff..f04afd1cafe0 100644 --- a/drivers/i2c/busses/i2c-omap.c +++ b/drivers/i2c/busses/i2c-omap.c @@ -1037,6 +1037,20 @@ static const struct i2c_algorithm omap_i2c_algo = { }; #ifdef CONFIG_OF +static struct omap_i2c_bus_platform_data omap2420_pdata = { + .rev = OMAP_I2C_IP_VERSION_1, + .flags = OMAP_I2C_FLAG_NO_FIFO | + OMAP_I2C_FLAG_SIMPLE_CLOCK | + OMAP_I2C_FLAG_16BIT_DATA_REG | + OMAP_I2C_FLAG_BUS_SHIFT_2, +}; + +static struct omap_i2c_bus_platform_data omap2430_pdata = { + .rev = OMAP_I2C_IP_VERSION_1, + .flags = OMAP_I2C_FLAG_BUS_SHIFT_2 | + OMAP_I2C_FLAG_FORCE_19200_INT_CLK, +}; + static struct omap_i2c_bus_platform_data omap3_pdata = { .rev = OMAP_I2C_IP_VERSION_1, .flags = OMAP_I2C_FLAG_BUS_SHIFT_2, @@ -1055,6 +1069,14 @@ static const struct of_device_id omap_i2c_of_match[] = { .compatible = "ti,omap3-i2c", .data = &omap3_pdata, }, + { + .compatible = "ti,omap2430-i2c", + .data = &omap2430_pdata, + }, + { + .compatible = "ti,omap2420-i2c", + .data = &omap2420_pdata, + }, { }, }; MODULE_DEVICE_TABLE(of, omap_i2c_of_match); -- cgit v1.2.3 From fd8e198cfcaa8abcc7f7525619d447f9a805e86e Mon Sep 17 00:00:00 2001 From: Alexandre Courbot Date: Sat, 16 Nov 2013 21:34:21 +0900 Subject: Documentation: gpiolib: document new interface gpiolib now exports a new descriptor-based interface which deprecates the older integer-based one. This patch documents this new interface and also takes the opportunity to brush-up the GPIO documentation a little bit. The new descriptor-based interface follows the same consumer/driver model as many other kernel subsystems (e.g. clock, regulator), so its documentation has similarly been splitted into different files. The content of the former documentation has been reused whenever it made sense; however, some of its content did not apply to the new interface anymore and have this been removed. Likewise, new sections like the mapping of GPIOs to devices have been written from scratch. The deprecated legacy-based documentation is still available, untouched, under Documentation/gpio/gpio-legacy.txt. Signed-off-by: Alexandre Courbot Signed-off-by: Linus Walleij --- Documentation/gpio.txt | 775 ------------------------------------- Documentation/gpio/board.txt | 115 ++++++ Documentation/gpio/consumer.txt | 197 ++++++++++ Documentation/gpio/driver.txt | 75 ++++ Documentation/gpio/gpio-legacy.txt | 775 +++++++++++++++++++++++++++++++++++++ Documentation/gpio/gpio.txt | 119 ++++++ Documentation/gpio/sysfs.txt | 155 ++++++++ 7 files changed, 1436 insertions(+), 775 deletions(-) delete mode 100644 Documentation/gpio.txt create mode 100644 Documentation/gpio/board.txt create mode 100644 Documentation/gpio/consumer.txt create mode 100644 Documentation/gpio/driver.txt create mode 100644 Documentation/gpio/gpio-legacy.txt create mode 100644 Documentation/gpio/gpio.txt create mode 100644 Documentation/gpio/sysfs.txt (limited to 'Documentation') diff --git a/Documentation/gpio.txt b/Documentation/gpio.txt deleted file mode 100644 index 6f83fa965b4b..000000000000 --- a/Documentation/gpio.txt +++ /dev/null @@ -1,775 +0,0 @@ -GPIO Interfaces - -This provides an overview of GPIO access conventions on Linux. - -These calls use the gpio_* naming prefix. No other calls should use that -prefix, or the related __gpio_* prefix. - - -What is a GPIO? -=============== -A "General Purpose Input/Output" (GPIO) is a flexible software-controlled -digital signal. They are provided from many kinds of chip, and are familiar -to Linux developers working with embedded and custom hardware. Each GPIO -represents a bit connected to a particular pin, or "ball" on Ball Grid Array -(BGA) packages. Board schematics show which external hardware connects to -which GPIOs. Drivers can be written generically, so that board setup code -passes such pin configuration data to drivers. - -System-on-Chip (SOC) processors heavily rely on GPIOs. In some cases, every -non-dedicated pin can be configured as a GPIO; and most chips have at least -several dozen of them. Programmable logic devices (like FPGAs) can easily -provide GPIOs; multifunction chips like power managers, and audio codecs -often have a few such pins to help with pin scarcity on SOCs; and there are -also "GPIO Expander" chips that connect using the I2C or SPI serial busses. -Most PC southbridges have a few dozen GPIO-capable pins (with only the BIOS -firmware knowing how they're used). - -The exact capabilities of GPIOs vary between systems. Common options: - - - Output values are writable (high=1, low=0). Some chips also have - options about how that value is driven, so that for example only one - value might be driven ... supporting "wire-OR" and similar schemes - for the other value (notably, "open drain" signaling). - - - Input values are likewise readable (1, 0). Some chips support readback - of pins configured as "output", which is very useful in such "wire-OR" - cases (to support bidirectional signaling). GPIO controllers may have - input de-glitch/debounce logic, sometimes with software controls. - - - Inputs can often be used as IRQ signals, often edge triggered but - sometimes level triggered. Such IRQs may be configurable as system - wakeup events, to wake the system from a low power state. - - - Usually a GPIO will be configurable as either input or output, as needed - by different product boards; single direction ones exist too. - - - Most GPIOs can be accessed while holding spinlocks, but those accessed - through a serial bus normally can't. Some systems support both types. - -On a given board each GPIO is used for one specific purpose like monitoring -MMC/SD card insertion/removal, detecting card writeprotect status, driving -a LED, configuring a transceiver, bitbanging a serial bus, poking a hardware -watchdog, sensing a switch, and so on. - - -GPIO conventions -================ -Note that this is called a "convention" because you don't need to do it this -way, and it's no crime if you don't. There **are** cases where portability -is not the main issue; GPIOs are often used for the kind of board-specific -glue logic that may even change between board revisions, and can't ever be -used on a board that's wired differently. Only least-common-denominator -functionality can be very portable. Other features are platform-specific, -and that can be critical for glue logic. - -Plus, this doesn't require any implementation framework, just an interface. -One platform might implement it as simple inline functions accessing chip -registers; another might implement it by delegating through abstractions -used for several very different kinds of GPIO controller. (There is some -optional code supporting such an implementation strategy, described later -in this document, but drivers acting as clients to the GPIO interface must -not care how it's implemented.) - -That said, if the convention is supported on their platform, drivers should -use it when possible. Platforms must select ARCH_REQUIRE_GPIOLIB or -ARCH_WANT_OPTIONAL_GPIOLIB in their Kconfig. Drivers that can't work without -standard GPIO calls should have Kconfig entries which depend on GPIOLIB. The -GPIO calls are available, either as "real code" or as optimized-away stubs, -when drivers use the include file: - - #include - -If you stick to this convention then it'll be easier for other developers to -see what your code is doing, and help maintain it. - -Note that these operations include I/O barriers on platforms which need to -use them; drivers don't need to add them explicitly. - - -Identifying GPIOs ------------------ -GPIOs are identified by unsigned integers in the range 0..MAX_INT. That -reserves "negative" numbers for other purposes like marking signals as -"not available on this board", or indicating faults. Code that doesn't -touch the underlying hardware treats these integers as opaque cookies. - -Platforms define how they use those integers, and usually #define symbols -for the GPIO lines so that board-specific setup code directly corresponds -to the relevant schematics. In contrast, drivers should only use GPIO -numbers passed to them from that setup code, using platform_data to hold -board-specific pin configuration data (along with other board specific -data they need). That avoids portability problems. - -So for example one platform uses numbers 32-159 for GPIOs; while another -uses numbers 0..63 with one set of GPIO controllers, 64-79 with another -type of GPIO controller, and on one particular board 80-95 with an FPGA. -The numbers need not be contiguous; either of those platforms could also -use numbers 2000-2063 to identify GPIOs in a bank of I2C GPIO expanders. - -If you want to initialize a structure with an invalid GPIO number, use -some negative number (perhaps "-EINVAL"); that will never be valid. To -test if such number from such a structure could reference a GPIO, you -may use this predicate: - - int gpio_is_valid(int number); - -A number that's not valid will be rejected by calls which may request -or free GPIOs (see below). Other numbers may also be rejected; for -example, a number might be valid but temporarily unused on a given board. - -Whether a platform supports multiple GPIO controllers is a platform-specific -implementation issue, as are whether that support can leave "holes" in the space -of GPIO numbers, and whether new controllers can be added at runtime. Such issues -can affect things including whether adjacent GPIO numbers are both valid. - -Using GPIOs ------------ -The first thing a system should do with a GPIO is allocate it, using -the gpio_request() call; see later. - -One of the next things to do with a GPIO, often in board setup code when -setting up a platform_device using the GPIO, is mark its direction: - - /* set as input or output, returning 0 or negative errno */ - int gpio_direction_input(unsigned gpio); - int gpio_direction_output(unsigned gpio, int value); - -The return value is zero for success, else a negative errno. It should -be checked, since the get/set calls don't have error returns and since -misconfiguration is possible. You should normally issue these calls from -a task context. However, for spinlock-safe GPIOs it's OK to use them -before tasking is enabled, as part of early board setup. - -For output GPIOs, the value provided becomes the initial output value. -This helps avoid signal glitching during system startup. - -For compatibility with legacy interfaces to GPIOs, setting the direction -of a GPIO implicitly requests that GPIO (see below) if it has not been -requested already. That compatibility is being removed from the optional -gpiolib framework. - -Setting the direction can fail if the GPIO number is invalid, or when -that particular GPIO can't be used in that mode. It's generally a bad -idea to rely on boot firmware to have set the direction correctly, since -it probably wasn't validated to do more than boot Linux. (Similarly, -that board setup code probably needs to multiplex that pin as a GPIO, -and configure pullups/pulldowns appropriately.) - - -Spinlock-Safe GPIO access -------------------------- -Most GPIO controllers can be accessed with memory read/write instructions. -Those don't need to sleep, and can safely be done from inside hard -(nonthreaded) IRQ handlers and similar contexts. - -Use the following calls to access such GPIOs, -for which gpio_cansleep() will always return false (see below): - - /* GPIO INPUT: return zero or nonzero */ - int gpio_get_value(unsigned gpio); - - /* GPIO OUTPUT */ - void gpio_set_value(unsigned gpio, int value); - -The values are boolean, zero for low, nonzero for high. When reading the -value of an output pin, the value returned should be what's seen on the -pin ... that won't always match the specified output value, because of -issues including open-drain signaling and output latencies. - -The get/set calls have no error returns because "invalid GPIO" should have -been reported earlier from gpio_direction_*(). However, note that not all -platforms can read the value of output pins; those that can't should always -return zero. Also, using these calls for GPIOs that can't safely be accessed -without sleeping (see below) is an error. - -Platform-specific implementations are encouraged to optimize the two -calls to access the GPIO value in cases where the GPIO number (and for -output, value) are constant. It's normal for them to need only a couple -of instructions in such cases (reading or writing a hardware register), -and not to need spinlocks. Such optimized calls can make bitbanging -applications a lot more efficient (in both space and time) than spending -dozens of instructions on subroutine calls. - - -GPIO access that may sleep --------------------------- -Some GPIO controllers must be accessed using message based busses like I2C -or SPI. Commands to read or write those GPIO values require waiting to -get to the head of a queue to transmit a command and get its response. -This requires sleeping, which can't be done from inside IRQ handlers. - -Platforms that support this type of GPIO distinguish them from other GPIOs -by returning nonzero from this call (which requires a valid GPIO number, -which should have been previously allocated with gpio_request): - - int gpio_cansleep(unsigned gpio); - -To access such GPIOs, a different set of accessors is defined: - - /* GPIO INPUT: return zero or nonzero, might sleep */ - int gpio_get_value_cansleep(unsigned gpio); - - /* GPIO OUTPUT, might sleep */ - void gpio_set_value_cansleep(unsigned gpio, int value); - - -Accessing such GPIOs requires a context which may sleep, for example -a threaded IRQ handler, and those accessors must be used instead of -spinlock-safe accessors without the cansleep() name suffix. - -Other than the fact that these accessors might sleep, and will work -on GPIOs that can't be accessed from hardIRQ handlers, these calls act -the same as the spinlock-safe calls. - - ** IN ADDITION ** calls to setup and configure such GPIOs must be made -from contexts which may sleep, since they may need to access the GPIO -controller chip too: (These setup calls are usually made from board -setup or driver probe/teardown code, so this is an easy constraint.) - - gpio_direction_input() - gpio_direction_output() - gpio_request() - -## gpio_request_one() -## gpio_request_array() -## gpio_free_array() - - gpio_free() - gpio_set_debounce() - - - -Claiming and Releasing GPIOs ----------------------------- -To help catch system configuration errors, two calls are defined. - - /* request GPIO, returning 0 or negative errno. - * non-null labels may be useful for diagnostics. - */ - int gpio_request(unsigned gpio, const char *label); - - /* release previously-claimed GPIO */ - void gpio_free(unsigned gpio); - -Passing invalid GPIO numbers to gpio_request() will fail, as will requesting -GPIOs that have already been claimed with that call. The return value of -gpio_request() must be checked. You should normally issue these calls from -a task context. However, for spinlock-safe GPIOs it's OK to request GPIOs -before tasking is enabled, as part of early board setup. - -These calls serve two basic purposes. One is marking the signals which -are actually in use as GPIOs, for better diagnostics; systems may have -several hundred potential GPIOs, but often only a dozen are used on any -given board. Another is to catch conflicts, identifying errors when -(a) two or more drivers wrongly think they have exclusive use of that -signal, or (b) something wrongly believes it's safe to remove drivers -needed to manage a signal that's in active use. That is, requesting a -GPIO can serve as a kind of lock. - -Some platforms may also use knowledge about what GPIOs are active for -power management, such as by powering down unused chip sectors and, more -easily, gating off unused clocks. - -For GPIOs that use pins known to the pinctrl subsystem, that subsystem should -be informed of their use; a gpiolib driver's .request() operation may call -pinctrl_request_gpio(), and a gpiolib driver's .free() operation may call -pinctrl_free_gpio(). The pinctrl subsystem allows a pinctrl_request_gpio() -to succeed concurrently with a pin or pingroup being "owned" by a device for -pin multiplexing. - -Any programming of pin multiplexing hardware that is needed to route the -GPIO signal to the appropriate pin should occur within a GPIO driver's -.direction_input() or .direction_output() operations, and occur after any -setup of an output GPIO's value. This allows a glitch-free migration from a -pin's special function to GPIO. This is sometimes required when using a GPIO -to implement a workaround on signals typically driven by a non-GPIO HW block. - -Some platforms allow some or all GPIO signals to be routed to different pins. -Similarly, other aspects of the GPIO or pin may need to be configured, such as -pullup/pulldown. Platform software should arrange that any such details are -configured prior to gpio_request() being called for those GPIOs, e.g. using -the pinctrl subsystem's mapping table, so that GPIO users need not be aware -of these details. - -Also note that it's your responsibility to have stopped using a GPIO -before you free it. - -Considering in most cases GPIOs are actually configured right after they -are claimed, three additional calls are defined: - - /* request a single GPIO, with initial configuration specified by - * 'flags', identical to gpio_request() wrt other arguments and - * return value - */ - int gpio_request_one(unsigned gpio, unsigned long flags, const char *label); - - /* request multiple GPIOs in a single call - */ - int gpio_request_array(struct gpio *array, size_t num); - - /* release multiple GPIOs in a single call - */ - void gpio_free_array(struct gpio *array, size_t num); - -where 'flags' is currently defined to specify the following properties: - - * GPIOF_DIR_IN - to configure direction as input - * GPIOF_DIR_OUT - to configure direction as output - - * GPIOF_INIT_LOW - as output, set initial level to LOW - * GPIOF_INIT_HIGH - as output, set initial level to HIGH - * GPIOF_OPEN_DRAIN - gpio pin is open drain type. - * GPIOF_OPEN_SOURCE - gpio pin is open source type. - - * GPIOF_EXPORT_DIR_FIXED - export gpio to sysfs, keep direction - * GPIOF_EXPORT_DIR_CHANGEABLE - also export, allow changing direction - -since GPIOF_INIT_* are only valid when configured as output, so group valid -combinations as: - - * GPIOF_IN - configure as input - * GPIOF_OUT_INIT_LOW - configured as output, initial level LOW - * GPIOF_OUT_INIT_HIGH - configured as output, initial level HIGH - -When setting the flag as GPIOF_OPEN_DRAIN then it will assume that pins is -open drain type. Such pins will not be driven to 1 in output mode. It is -require to connect pull-up on such pins. By enabling this flag, gpio lib will -make the direction to input when it is asked to set value of 1 in output mode -to make the pin HIGH. The pin is make to LOW by driving value 0 in output mode. - -When setting the flag as GPIOF_OPEN_SOURCE then it will assume that pins is -open source type. Such pins will not be driven to 0 in output mode. It is -require to connect pull-down on such pin. By enabling this flag, gpio lib will -make the direction to input when it is asked to set value of 0 in output mode -to make the pin LOW. The pin is make to HIGH by driving value 1 in output mode. - -In the future, these flags can be extended to support more properties. - -Further more, to ease the claim/release of multiple GPIOs, 'struct gpio' is -introduced to encapsulate all three fields as: - - struct gpio { - unsigned gpio; - unsigned long flags; - const char *label; - }; - -A typical example of usage: - - static struct gpio leds_gpios[] = { - { 32, GPIOF_OUT_INIT_HIGH, "Power LED" }, /* default to ON */ - { 33, GPIOF_OUT_INIT_LOW, "Green LED" }, /* default to OFF */ - { 34, GPIOF_OUT_INIT_LOW, "Red LED" }, /* default to OFF */ - { 35, GPIOF_OUT_INIT_LOW, "Blue LED" }, /* default to OFF */ - { ... }, - }; - - err = gpio_request_one(31, GPIOF_IN, "Reset Button"); - if (err) - ... - - err = gpio_request_array(leds_gpios, ARRAY_SIZE(leds_gpios)); - if (err) - ... - - gpio_free_array(leds_gpios, ARRAY_SIZE(leds_gpios)); - - -GPIOs mapped to IRQs --------------------- -GPIO numbers are unsigned integers; so are IRQ numbers. These make up -two logically distinct namespaces (GPIO 0 need not use IRQ 0). You can -map between them using calls like: - - /* map GPIO numbers to IRQ numbers */ - int gpio_to_irq(unsigned gpio); - - /* map IRQ numbers to GPIO numbers (avoid using this) */ - int irq_to_gpio(unsigned irq); - -Those return either the corresponding number in the other namespace, or -else a negative errno code if the mapping can't be done. (For example, -some GPIOs can't be used as IRQs.) It is an unchecked error to use a GPIO -number that wasn't set up as an input using gpio_direction_input(), or -to use an IRQ number that didn't originally come from gpio_to_irq(). - -These two mapping calls are expected to cost on the order of a single -addition or subtraction. They're not allowed to sleep. - -Non-error values returned from gpio_to_irq() can be passed to request_irq() -or free_irq(). They will often be stored into IRQ resources for platform -devices, by the board-specific initialization code. Note that IRQ trigger -options are part of the IRQ interface, e.g. IRQF_TRIGGER_FALLING, as are -system wakeup capabilities. - -Non-error values returned from irq_to_gpio() would most commonly be used -with gpio_get_value(), for example to initialize or update driver state -when the IRQ is edge-triggered. Note that some platforms don't support -this reverse mapping, so you should avoid using it. - - -Emulating Open Drain Signals ----------------------------- -Sometimes shared signals need to use "open drain" signaling, where only the -low signal level is actually driven. (That term applies to CMOS transistors; -"open collector" is used for TTL.) A pullup resistor causes the high signal -level. This is sometimes called a "wire-AND"; or more practically, from the -negative logic (low=true) perspective this is a "wire-OR". - -One common example of an open drain signal is a shared active-low IRQ line. -Also, bidirectional data bus signals sometimes use open drain signals. - -Some GPIO controllers directly support open drain outputs; many don't. When -you need open drain signaling but your hardware doesn't directly support it, -there's a common idiom you can use to emulate it with any GPIO pin that can -be used as either an input or an output: - - LOW: gpio_direction_output(gpio, 0) ... this drives the signal - and overrides the pullup. - - HIGH: gpio_direction_input(gpio) ... this turns off the output, - so the pullup (or some other device) controls the signal. - -If you are "driving" the signal high but gpio_get_value(gpio) reports a low -value (after the appropriate rise time passes), you know some other component -is driving the shared signal low. That's not necessarily an error. As one -common example, that's how I2C clocks are stretched: a slave that needs a -slower clock delays the rising edge of SCK, and the I2C master adjusts its -signaling rate accordingly. - - -GPIO controllers and the pinctrl subsystem ------------------------------------------- - -A GPIO controller on a SOC might be tightly coupled with the pinctrl -subsystem, in the sense that the pins can be used by other functions -together with an optional gpio feature. We have already covered the -case where e.g. a GPIO controller need to reserve a pin or set the -direction of a pin by calling any of: - -pinctrl_request_gpio() -pinctrl_free_gpio() -pinctrl_gpio_direction_input() -pinctrl_gpio_direction_output() - -But how does the pin control subsystem cross-correlate the GPIO -numbers (which are a global business) to a certain pin on a certain -pin controller? - -This is done by registering "ranges" of pins, which are essentially -cross-reference tables. These are described in -Documentation/pinctrl.txt - -While the pin allocation is totally managed by the pinctrl subsystem, -gpio (under gpiolib) is still maintained by gpio drivers. It may happen -that different pin ranges in a SoC is managed by different gpio drivers. - -This makes it logical to let gpio drivers announce their pin ranges to -the pin ctrl subsystem before it will call 'pinctrl_request_gpio' in order -to request the corresponding pin to be prepared by the pinctrl subsystem -before any gpio usage. - -For this, the gpio controller can register its pin range with pinctrl -subsystem. There are two ways of doing it currently: with or without DT. - -For with DT support refer to Documentation/devicetree/bindings/gpio/gpio.txt. - -For non-DT support, user can call gpiochip_add_pin_range() with appropriate -parameters to register a range of gpio pins with a pinctrl driver. For this -exact name string of pinctrl device has to be passed as one of the -argument to this routine. - - -What do these conventions omit? -=============================== -One of the biggest things these conventions omit is pin multiplexing, since -this is highly chip-specific and nonportable. One platform might not need -explicit multiplexing; another might have just two options for use of any -given pin; another might have eight options per pin; another might be able -to route a given GPIO to any one of several pins. (Yes, those examples all -come from systems that run Linux today.) - -Related to multiplexing is configuration and enabling of the pullups or -pulldowns integrated on some platforms. Not all platforms support them, -or support them in the same way; and any given board might use external -pullups (or pulldowns) so that the on-chip ones should not be used. -(When a circuit needs 5 kOhm, on-chip 100 kOhm resistors won't do.) -Likewise drive strength (2 mA vs 20 mA) and voltage (1.8V vs 3.3V) is a -platform-specific issue, as are models like (not) having a one-to-one -correspondence between configurable pins and GPIOs. - -There are other system-specific mechanisms that are not specified here, -like the aforementioned options for input de-glitching and wire-OR output. -Hardware may support reading or writing GPIOs in gangs, but that's usually -configuration dependent: for GPIOs sharing the same bank. (GPIOs are -commonly grouped in banks of 16 or 32, with a given SOC having several such -banks.) Some systems can trigger IRQs from output GPIOs, or read values -from pins not managed as GPIOs. Code relying on such mechanisms will -necessarily be nonportable. - -Dynamic definition of GPIOs is not currently standard; for example, as -a side effect of configuring an add-on board with some GPIO expanders. - - -GPIO implementor's framework (OPTIONAL) -======================================= -As noted earlier, there is an optional implementation framework making it -easier for platforms to support different kinds of GPIO controller using -the same programming interface. This framework is called "gpiolib". - -As a debugging aid, if debugfs is available a /sys/kernel/debug/gpio file -will be found there. That will list all the controllers registered through -this framework, and the state of the GPIOs currently in use. - - -Controller Drivers: gpio_chip ------------------------------ -In this framework each GPIO controller is packaged as a "struct gpio_chip" -with information common to each controller of that type: - - - methods to establish GPIO direction - - methods used to access GPIO values - - flag saying whether calls to its methods may sleep - - optional debugfs dump method (showing extra state like pullup config) - - label for diagnostics - -There is also per-instance data, which may come from device.platform_data: -the number of its first GPIO, and how many GPIOs it exposes. - -The code implementing a gpio_chip should support multiple instances of the -controller, possibly using the driver model. That code will configure each -gpio_chip and issue gpiochip_add(). Removing a GPIO controller should be -rare; use gpiochip_remove() when it is unavoidable. - -Most often a gpio_chip is part of an instance-specific structure with state -not exposed by the GPIO interfaces, such as addressing, power management, -and more. Chips such as codecs will have complex non-GPIO state. - -Any debugfs dump method should normally ignore signals which haven't been -requested as GPIOs. They can use gpiochip_is_requested(), which returns -either NULL or the label associated with that GPIO when it was requested. - - -Platform Support ----------------- -To support this framework, a platform's Kconfig will "select" either -ARCH_REQUIRE_GPIOLIB or ARCH_WANT_OPTIONAL_GPIOLIB -and arrange that its includes and defines -three functions: gpio_get_value(), gpio_set_value(), and gpio_cansleep(). - -It may also provide a custom value for ARCH_NR_GPIOS, so that it better -reflects the number of GPIOs in actual use on that platform, without -wasting static table space. (It should count both built-in/SoC GPIOs and -also ones on GPIO expanders. - -ARCH_REQUIRE_GPIOLIB means that the gpiolib code will always get compiled -into the kernel on that architecture. - -ARCH_WANT_OPTIONAL_GPIOLIB means the gpiolib code defaults to off and the user -can enable it and build it into the kernel optionally. - -If neither of these options are selected, the platform does not support -GPIOs through GPIO-lib and the code cannot be enabled by the user. - -Trivial implementations of those functions can directly use framework -code, which always dispatches through the gpio_chip: - - #define gpio_get_value __gpio_get_value - #define gpio_set_value __gpio_set_value - #define gpio_cansleep __gpio_cansleep - -Fancier implementations could instead define those as inline functions with -logic optimizing access to specific SOC-based GPIOs. For example, if the -referenced GPIO is the constant "12", getting or setting its value could -cost as little as two or three instructions, never sleeping. When such an -optimization is not possible those calls must delegate to the framework -code, costing at least a few dozen instructions. For bitbanged I/O, such -instruction savings can be significant. - -For SOCs, platform-specific code defines and registers gpio_chip instances -for each bank of on-chip GPIOs. Those GPIOs should be numbered/labeled to -match chip vendor documentation, and directly match board schematics. They -may well start at zero and go up to a platform-specific limit. Such GPIOs -are normally integrated into platform initialization to make them always be -available, from arch_initcall() or earlier; they can often serve as IRQs. - - -Board Support -------------- -For external GPIO controllers -- such as I2C or SPI expanders, ASICs, multi -function devices, FPGAs or CPLDs -- most often board-specific code handles -registering controller devices and ensures that their drivers know what GPIO -numbers to use with gpiochip_add(). Their numbers often start right after -platform-specific GPIOs. - -For example, board setup code could create structures identifying the range -of GPIOs that chip will expose, and passes them to each GPIO expander chip -using platform_data. Then the chip driver's probe() routine could pass that -data to gpiochip_add(). - -Initialization order can be important. For example, when a device relies on -an I2C-based GPIO, its probe() routine should only be called after that GPIO -becomes available. That may mean the device should not be registered until -calls for that GPIO can work. One way to address such dependencies is for -such gpio_chip controllers to provide setup() and teardown() callbacks to -board specific code; those board specific callbacks would register devices -once all the necessary resources are available, and remove them later when -the GPIO controller device becomes unavailable. - - -Sysfs Interface for Userspace (OPTIONAL) -======================================== -Platforms which use the "gpiolib" implementors framework may choose to -configure a sysfs user interface to GPIOs. This is different from the -debugfs interface, since it provides control over GPIO direction and -value instead of just showing a gpio state summary. Plus, it could be -present on production systems without debugging support. - -Given appropriate hardware documentation for the system, userspace could -know for example that GPIO #23 controls the write protect line used to -protect boot loader segments in flash memory. System upgrade procedures -may need to temporarily remove that protection, first importing a GPIO, -then changing its output state, then updating the code before re-enabling -the write protection. In normal use, GPIO #23 would never be touched, -and the kernel would have no need to know about it. - -Again depending on appropriate hardware documentation, on some systems -userspace GPIO can be used to determine system configuration data that -standard kernels won't know about. And for some tasks, simple userspace -GPIO drivers could be all that the system really needs. - -Note that standard kernel drivers exist for common "LEDs and Buttons" -GPIO tasks: "leds-gpio" and "gpio_keys", respectively. Use those -instead of talking directly to the GPIOs; they integrate with kernel -frameworks better than your userspace code could. - - -Paths in Sysfs --------------- -There are three kinds of entry in /sys/class/gpio: - - - Control interfaces used to get userspace control over GPIOs; - - - GPIOs themselves; and - - - GPIO controllers ("gpio_chip" instances). - -That's in addition to standard files including the "device" symlink. - -The control interfaces are write-only: - - /sys/class/gpio/ - - "export" ... Userspace may ask the kernel to export control of - a GPIO to userspace by writing its number to this file. - - Example: "echo 19 > export" will create a "gpio19" node - for GPIO #19, if that's not requested by kernel code. - - "unexport" ... Reverses the effect of exporting to userspace. - - Example: "echo 19 > unexport" will remove a "gpio19" - node exported using the "export" file. - -GPIO signals have paths like /sys/class/gpio/gpio42/ (for GPIO #42) -and have the following read/write attributes: - - /sys/class/gpio/gpioN/ - - "direction" ... reads as either "in" or "out". This value may - normally be written. Writing as "out" defaults to - initializing the value as low. To ensure glitch free - operation, values "low" and "high" may be written to - configure the GPIO as an output with that initial value. - - Note that this attribute *will not exist* if the kernel - doesn't support changing the direction of a GPIO, or - it was exported by kernel code that didn't explicitly - allow userspace to reconfigure this GPIO's direction. - - "value" ... reads as either 0 (low) or 1 (high). If the GPIO - is configured as an output, this value may be written; - any nonzero value is treated as high. - - If the pin can be configured as interrupt-generating interrupt - and if it has been configured to generate interrupts (see the - description of "edge"), you can poll(2) on that file and - poll(2) will return whenever the interrupt was triggered. If - you use poll(2), set the events POLLPRI and POLLERR. If you - use select(2), set the file descriptor in exceptfds. After - poll(2) returns, either lseek(2) to the beginning of the sysfs - file and read the new value or close the file and re-open it - to read the value. - - "edge" ... reads as either "none", "rising", "falling", or - "both". Write these strings to select the signal edge(s) - that will make poll(2) on the "value" file return. - - This file exists only if the pin can be configured as an - interrupt generating input pin. - - "active_low" ... reads as either 0 (false) or 1 (true). Write - any nonzero value to invert the value attribute both - for reading and writing. Existing and subsequent - poll(2) support configuration via the edge attribute - for "rising" and "falling" edges will follow this - setting. - -GPIO controllers have paths like /sys/class/gpio/gpiochip42/ (for the -controller implementing GPIOs starting at #42) and have the following -read-only attributes: - - /sys/class/gpio/gpiochipN/ - - "base" ... same as N, the first GPIO managed by this chip - - "label" ... provided for diagnostics (not always unique) - - "ngpio" ... how many GPIOs this manges (N to N + ngpio - 1) - -Board documentation should in most cases cover what GPIOs are used for -what purposes. However, those numbers are not always stable; GPIOs on -a daughtercard might be different depending on the base board being used, -or other cards in the stack. In such cases, you may need to use the -gpiochip nodes (possibly in conjunction with schematics) to determine -the correct GPIO number to use for a given signal. - - -Exporting from Kernel code --------------------------- -Kernel code can explicitly manage exports of GPIOs which have already been -requested using gpio_request(): - - /* export the GPIO to userspace */ - int gpio_export(unsigned gpio, bool direction_may_change); - - /* reverse gpio_export() */ - void gpio_unexport(); - - /* create a sysfs link to an exported GPIO node */ - int gpio_export_link(struct device *dev, const char *name, - unsigned gpio) - - /* change the polarity of a GPIO node in sysfs */ - int gpio_sysfs_set_active_low(unsigned gpio, int value); - -After a kernel driver requests a GPIO, it may only be made available in -the sysfs interface by gpio_export(). The driver can control whether the -signal direction may change. This helps drivers prevent userspace code -from accidentally clobbering important system state. - -This explicit exporting can help with debugging (by making some kinds -of experiments easier), or can provide an always-there interface that's -suitable for documenting as part of a board support package. - -After the GPIO has been exported, gpio_export_link() allows creating -symlinks from elsewhere in sysfs to the GPIO sysfs node. Drivers can -use this to provide the interface under their own device in sysfs with -a descriptive name. - -Drivers can use gpio_sysfs_set_active_low() to hide GPIO line polarity -differences between boards from user space. This only affects the -sysfs interface. Polarity change can be done both before and after -gpio_export(), and previously enabled poll(2) support for either -rising or falling edge will be reconfigured to follow this setting. diff --git a/Documentation/gpio/board.txt b/Documentation/gpio/board.txt new file mode 100644 index 000000000000..0d03506f2cc5 --- /dev/null +++ b/Documentation/gpio/board.txt @@ -0,0 +1,115 @@ +GPIO Mappings +============= + +This document explains how GPIOs can be assigned to given devices and functions. +Note that it only applies to the new descriptor-based interface. For a +description of the deprecated integer-based GPIO interface please refer to +gpio-legacy.txt (actually, there is no real mapping possible with the old +interface; you just fetch an integer from somewhere and request the +corresponding GPIO. + +Platforms that make use of GPIOs must select ARCH_REQUIRE_GPIOLIB (if GPIO usage +is mandatory) or ARCH_WANT_OPTIONAL_GPIOLIB (if GPIO support can be omitted) in +their Kconfig. Then, how GPIOs are mapped depends on what the platform uses to +describe its hardware layout. Currently, mappings can be defined through device +tree, ACPI, and platform data. + +Device Tree +----------- +GPIOs can easily be mapped to devices and functions in the device tree. The +exact way to do it depends on the GPIO controller providing the GPIOs, see the +device tree bindings for your controller. + +GPIOs mappings are defined in the consumer device's node, in a property named +-gpios, where is the function the driver will request +through gpiod_get(). For example: + + foo_device { + compatible = "acme,foo"; + ... + led-gpios = <&gpio 15 GPIO_ACTIVE_HIGH>, /* red */ + <&gpio 16 GPIO_ACTIVE_HIGH>, /* green */ + <&gpio 17 GPIO_ACTIVE_HIGH>; /* blue */ + + power-gpio = <&gpio 1 GPIO_ACTIVE_LOW>; + }; + +This property will make GPIOs 15, 16 and 17 available to the driver under the +"led" function, and GPIO 1 as the "power" GPIO: + + struct gpio_desc *red, *green, *blue, *power; + + red = gpiod_get_index(dev, "led", 0); + green = gpiod_get_index(dev, "led", 1); + blue = gpiod_get_index(dev, "led", 2); + + power = gpiod_get(dev, "power"); + +The led GPIOs will be active-high, while the power GPIO will be active-low (i.e. +gpiod_is_active_low(power) will be true). + +ACPI +---- +ACPI does not support function names for GPIOs. Therefore, only the "idx" +argument of gpiod_get_index() is useful to discriminate between GPIOs assigned +to a device. The "con_id" argument can still be set for debugging purposes (it +will appear under error messages as well as debug and sysfs nodes). + +Platform Data +------------- +Finally, GPIOs can be bound to devices and functions using platform data. Board +files that desire to do so need to include the following header: + + #include + +GPIOs are mapped by the means of tables of lookups, containing instances of the +gpiod_lookup structure. Two macros are defined to help declaring such mappings: + + GPIO_LOOKUP(chip_label, chip_hwnum, dev_id, con_id, flags) + GPIO_LOOKUP_IDX(chip_label, chip_hwnum, dev_id, con_id, idx, flags) + +where + + - chip_label is the label of the gpiod_chip instance providing the GPIO + - chip_hwnum is the hardware number of the GPIO within the chip + - dev_id is the identifier of the device that will make use of this GPIO. If + NULL, the GPIO will be available to all devices. + - con_id is the name of the GPIO function from the device point of view. It + can be NULL. + - idx is the index of the GPIO within the function. + - flags is defined to specify the following properties: + * GPIOF_ACTIVE_LOW - to configure the GPIO as active-low + * GPIOF_OPEN_DRAIN - GPIO pin is open drain type. + * GPIOF_OPEN_SOURCE - GPIO pin is open source type. + +In the future, these flags might be extended to support more properties. + +Note that GPIO_LOOKUP() is just a shortcut to GPIO_LOOKUP_IDX() where idx = 0. + +A lookup table can then be defined as follows: + + struct gpiod_lookup gpios_table[] = { + GPIO_LOOKUP_IDX("gpio.0", 15, "foo.0", "led", 0, GPIO_ACTIVE_HIGH), + GPIO_LOOKUP_IDX("gpio.0", 16, "foo.0", "led", 1, GPIO_ACTIVE_HIGH), + GPIO_LOOKUP_IDX("gpio.0", 17, "foo.0", "led", 2, GPIO_ACTIVE_HIGH), + GPIO_LOOKUP("gpio.0", 1, "foo.0", "power", GPIO_ACTIVE_LOW), + }; + +And the table can be added by the board code as follows: + + gpiod_add_table(gpios_table, ARRAY_SIZE(gpios_table)); + +The driver controlling "foo.0" will then be able to obtain its GPIOs as follows: + + struct gpio_desc *red, *green, *blue, *power; + + red = gpiod_get_index(dev, "led", 0); + green = gpiod_get_index(dev, "led", 1); + blue = gpiod_get_index(dev, "led", 2); + + power = gpiod_get(dev, "power"); + gpiod_direction_output(power, 1); + +Since the "power" GPIO is mapped as active-low, its actual signal will be 0 +after this code. Contrary to the legacy integer GPIO interface, the active-low +property is handled during mapping and is thus transparent to GPIO consumers. diff --git a/Documentation/gpio/consumer.txt b/Documentation/gpio/consumer.txt new file mode 100644 index 000000000000..07c74a3765a0 --- /dev/null +++ b/Documentation/gpio/consumer.txt @@ -0,0 +1,197 @@ +GPIO Descriptor Consumer Interface +================================== + +This document describes the consumer interface of the GPIO framework. Note that +it describes the new descriptor-based interface. For a description of the +deprecated integer-based GPIO interface please refer to gpio-legacy.txt. + + +Guidelines for GPIOs consumers +============================== + +Drivers that can't work without standard GPIO calls should have Kconfig entries +that depend on GPIOLIB. The functions that allow a driver to obtain and use +GPIOs are available by including the following file: + + #include + +All the functions that work with the descriptor-based GPIO interface are +prefixed with gpiod_. The gpio_ prefix is used for the legacy interface. No +other function in the kernel should use these prefixes. + + +Obtaining and Disposing GPIOs +============================= + +With the descriptor-based interface, GPIOs are identified with an opaque, +non-forgeable handler that must be obtained through a call to one of the +gpiod_get() functions. Like many other kernel subsystems, gpiod_get() takes the +device that will use the GPIO and the function the requested GPIO is supposed to +fulfill: + + struct gpio_desc *gpiod_get(struct device *dev, const char *con_id) + +If a function is implemented by using several GPIOs together (e.g. a simple LED +device that displays digits), an additional index argument can be specified: + + struct gpio_desc *gpiod_get_index(struct device *dev, + const char *con_id, unsigned int idx) + +Both functions return either a valid GPIO descriptor, or an error code checkable +with IS_ERR(). They will never return a NULL pointer. + +Device-managed variants of these functions are also defined: + + struct gpio_desc *devm_gpiod_get(struct device *dev, const char *con_id) + + struct gpio_desc *devm_gpiod_get_index(struct device *dev, + const char *con_id, + unsigned int idx) + +A GPIO descriptor can be disposed of using the gpiod_put() function: + + void gpiod_put(struct gpio_desc *desc) + +It is strictly forbidden to use a descriptor after calling this function. The +device-managed variant is, unsurprisingly: + + void devm_gpiod_put(struct device *dev, struct gpio_desc *desc) + + +Using GPIOs +=========== + +Setting Direction +----------------- +The first thing a driver must do with a GPIO is setting its direction. This is +done by invoking one of the gpiod_direction_*() functions: + + int gpiod_direction_input(struct gpio_desc *desc) + int gpiod_direction_output(struct gpio_desc *desc, int value) + +The return value is zero for success, else a negative errno. It should be +checked, since the get/set calls don't return errors and since misconfiguration +is possible. You should normally issue these calls from a task context. However, +for spinlock-safe GPIOs it is OK to use them before tasking is enabled, as part +of early board setup. + +For output GPIOs, the value provided becomes the initial output value. This +helps avoid signal glitching during system startup. + +A driver can also query the current direction of a GPIO: + + int gpiod_get_direction(const struct gpio_desc *desc) + +This function will return either GPIOF_DIR_IN or GPIOF_DIR_OUT. + +Be aware that there is no default direction for GPIOs. Therefore, **using a GPIO +without setting its direction first is illegal and will result in undefined +behavior!** + + +Spinlock-Safe GPIO Access +------------------------- +Most GPIO controllers can be accessed with memory read/write instructions. Those +don't need to sleep, and can safely be done from inside hard (non-threaded) IRQ +handlers and similar contexts. + +Use the following calls to access GPIOs from an atomic context: + + int gpiod_get_value(const struct gpio_desc *desc); + void gpiod_set_value(struct gpio_desc *desc, int value); + +The values are boolean, zero for low, nonzero for high. When reading the value +of an output pin, the value returned should be what's seen on the pin. That +won't always match the specified output value, because of issues including +open-drain signaling and output latencies. + +The get/set calls do not return errors because "invalid GPIO" should have been +reported earlier from gpiod_direction_*(). However, note that not all platforms +can read the value of output pins; those that can't should always return zero. +Also, using these calls for GPIOs that can't safely be accessed without sleeping +(see below) is an error. + + +GPIO Access That May Sleep +-------------------------- +Some GPIO controllers must be accessed using message based buses like I2C or +SPI. Commands to read or write those GPIO values require waiting to get to the +head of a queue to transmit a command and get its response. This requires +sleeping, which can't be done from inside IRQ handlers. + +Platforms that support this type of GPIO distinguish them from other GPIOs by +returning nonzero from this call: + + int gpiod_cansleep(const struct gpio_desc *desc) + +To access such GPIOs, a different set of accessors is defined: + + int gpiod_get_value_cansleep(const struct gpio_desc *desc) + void gpiod_set_value_cansleep(struct gpio_desc *desc, int value) + +Accessing such GPIOs requires a context which may sleep, for example a threaded +IRQ handler, and those accessors must be used instead of spinlock-safe +accessors without the cansleep() name suffix. + +Other than the fact that these accessors might sleep, and will work on GPIOs +that can't be accessed from hardIRQ handlers, these calls act the same as the +spinlock-safe calls. + + +Active-low State and Raw GPIO Values +------------------------------------ +Device drivers like to manage the logical state of a GPIO, i.e. the value their +device will actually receive, no matter what lies between it and the GPIO line. +In some cases, it might make sense to control the actual GPIO line value. The +following set of calls ignore the active-low property of a GPIO and work on the +raw line value: + + int gpiod_get_raw_value(const struct gpio_desc *desc) + void gpiod_set_raw_value(struct gpio_desc *desc, int value) + int gpiod_get_raw_value_cansleep(const struct gpio_desc *desc) + void gpiod_set_raw_value_cansleep(struct gpio_desc *desc, int value) + +The active-low state of a GPIO can also be queried using the following call: + + int gpiod_is_active_low(const struct gpio_desc *desc) + +Note that these functions should only be used with great moderation ; a driver +should not have to care about the physical line level. + +GPIOs mapped to IRQs +-------------------- +GPIO lines can quite often be used as IRQs. You can get the IRQ number +corresponding to a given GPIO using the following call: + + int gpiod_to_irq(const struct gpio_desc *desc) + +It will return an IRQ number, or an negative errno code if the mapping can't be +done (most likely because that particular GPIO cannot be used as IRQ). It is an +unchecked error to use a GPIO that wasn't set up as an input using +gpiod_direction_input(), or to use an IRQ number that didn't originally come +from gpiod_to_irq(). gpiod_to_irq() is not allowed to sleep. + +Non-error values returned from gpiod_to_irq() can be passed to request_irq() or +free_irq(). They will often be stored into IRQ resources for platform devices, +by the board-specific initialization code. Note that IRQ trigger options are +part of the IRQ interface, e.g. IRQF_TRIGGER_FALLING, as are system wakeup +capabilities. + + +Interacting With the Legacy GPIO Subsystem +========================================== +Many kernel subsystems still handle GPIOs using the legacy integer-based +interface. Although it is strongly encouraged to upgrade them to the safer +descriptor-based API, the following two functions allow you to convert a GPIO +descriptor into the GPIO integer namespace and vice-versa: + + int desc_to_gpio(const struct gpio_desc *desc) + struct gpio_desc *gpio_to_desc(unsigned gpio) + +The GPIO number returned by desc_to_gpio() can be safely used as long as the +GPIO descriptor has not been freed. All the same, a GPIO number passed to +gpio_to_desc() must have been properly acquired, and usage of the returned GPIO +descriptor is only possible after the GPIO number has been released. + +Freeing a GPIO obtained by one API with the other API is forbidden and an +unchecked error. diff --git a/Documentation/gpio/driver.txt b/Documentation/gpio/driver.txt new file mode 100644 index 000000000000..9da0bfa74781 --- /dev/null +++ b/Documentation/gpio/driver.txt @@ -0,0 +1,75 @@ +GPIO Descriptor Driver Interface +================================ + +This document serves as a guide for GPIO chip drivers writers. Note that it +describes the new descriptor-based interface. For a description of the +deprecated integer-based GPIO interface please refer to gpio-legacy.txt. + +Each GPIO controller driver needs to include the following header, which defines +the structures used to define a GPIO driver: + + #include + + +Internal Representation of GPIOs +================================ + +Inside a GPIO driver, individual GPIOs are identified by their hardware number, +which is a unique number between 0 and n, n being the number of GPIOs managed by +the chip. This number is purely internal: the hardware number of a particular +GPIO descriptor is never made visible outside of the driver. + +On top of this internal number, each GPIO also need to have a global number in +the integer GPIO namespace so that it can be used with the legacy GPIO +interface. Each chip must thus have a "base" number (which can be automatically +assigned), and for each GPIO the global number will be (base + hardware number). +Although the integer representation is considered deprecated, it still has many +users and thus needs to be maintained. + +So for example one platform could use numbers 32-159 for GPIOs, with a +controller defining 128 GPIOs at a "base" of 32 ; while another platform uses +numbers 0..63 with one set of GPIO controllers, 64-79 with another type of GPIO +controller, and on one particular board 80-95 with an FPGA. The numbers need not +be contiguous; either of those platforms could also use numbers 2000-2063 to +identify GPIOs in a bank of I2C GPIO expanders. + + +Controller Drivers: gpio_chip +============================= + +In the gpiolib framework each GPIO controller is packaged as a "struct +gpio_chip" (see linux/gpio/driver.h for its complete definition) with members +common to each controller of that type: + + - methods to establish GPIO direction + - methods used to access GPIO values + - method to return the IRQ number associated to a given GPIO + - flag saying whether calls to its methods may sleep + - optional debugfs dump method (showing extra state like pullup config) + - optional base number (will be automatically assigned if omitted) + - label for diagnostics and GPIOs mapping using platform data + +The code implementing a gpio_chip should support multiple instances of the +controller, possibly using the driver model. That code will configure each +gpio_chip and issue gpiochip_add(). Removing a GPIO controller should be rare; +use gpiochip_remove() when it is unavoidable. + +Most often a gpio_chip is part of an instance-specific structure with state not +exposed by the GPIO interfaces, such as addressing, power management, and more. +Chips such as codecs will have complex non-GPIO state. + +Any debugfs dump method should normally ignore signals which haven't been +requested as GPIOs. They can use gpiochip_is_requested(), which returns either +NULL or the label associated with that GPIO when it was requested. + +Locking IRQ usage +----------------- +Input GPIOs can be used as IRQ signals. When this happens, a driver is requested +to mark the GPIO as being used as an IRQ: + + int gpiod_lock_as_irq(struct gpio_desc *desc) + +This will prevent the use of non-irq related GPIO APIs until the GPIO IRQ lock +is released: + + void gpiod_unlock_as_irq(struct gpio_desc *desc) diff --git a/Documentation/gpio/gpio-legacy.txt b/Documentation/gpio/gpio-legacy.txt new file mode 100644 index 000000000000..6f83fa965b4b --- /dev/null +++ b/Documentation/gpio/gpio-legacy.txt @@ -0,0 +1,775 @@ +GPIO Interfaces + +This provides an overview of GPIO access conventions on Linux. + +These calls use the gpio_* naming prefix. No other calls should use that +prefix, or the related __gpio_* prefix. + + +What is a GPIO? +=============== +A "General Purpose Input/Output" (GPIO) is a flexible software-controlled +digital signal. They are provided from many kinds of chip, and are familiar +to Linux developers working with embedded and custom hardware. Each GPIO +represents a bit connected to a particular pin, or "ball" on Ball Grid Array +(BGA) packages. Board schematics show which external hardware connects to +which GPIOs. Drivers can be written generically, so that board setup code +passes such pin configuration data to drivers. + +System-on-Chip (SOC) processors heavily rely on GPIOs. In some cases, every +non-dedicated pin can be configured as a GPIO; and most chips have at least +several dozen of them. Programmable logic devices (like FPGAs) can easily +provide GPIOs; multifunction chips like power managers, and audio codecs +often have a few such pins to help with pin scarcity on SOCs; and there are +also "GPIO Expander" chips that connect using the I2C or SPI serial busses. +Most PC southbridges have a few dozen GPIO-capable pins (with only the BIOS +firmware knowing how they're used). + +The exact capabilities of GPIOs vary between systems. Common options: + + - Output values are writable (high=1, low=0). Some chips also have + options about how that value is driven, so that for example only one + value might be driven ... supporting "wire-OR" and similar schemes + for the other value (notably, "open drain" signaling). + + - Input values are likewise readable (1, 0). Some chips support readback + of pins configured as "output", which is very useful in such "wire-OR" + cases (to support bidirectional signaling). GPIO controllers may have + input de-glitch/debounce logic, sometimes with software controls. + + - Inputs can often be used as IRQ signals, often edge triggered but + sometimes level triggered. Such IRQs may be configurable as system + wakeup events, to wake the system from a low power state. + + - Usually a GPIO will be configurable as either input or output, as needed + by different product boards; single direction ones exist too. + + - Most GPIOs can be accessed while holding spinlocks, but those accessed + through a serial bus normally can't. Some systems support both types. + +On a given board each GPIO is used for one specific purpose like monitoring +MMC/SD card insertion/removal, detecting card writeprotect status, driving +a LED, configuring a transceiver, bitbanging a serial bus, poking a hardware +watchdog, sensing a switch, and so on. + + +GPIO conventions +================ +Note that this is called a "convention" because you don't need to do it this +way, and it's no crime if you don't. There **are** cases where portability +is not the main issue; GPIOs are often used for the kind of board-specific +glue logic that may even change between board revisions, and can't ever be +used on a board that's wired differently. Only least-common-denominator +functionality can be very portable. Other features are platform-specific, +and that can be critical for glue logic. + +Plus, this doesn't require any implementation framework, just an interface. +One platform might implement it as simple inline functions accessing chip +registers; another might implement it by delegating through abstractions +used for several very different kinds of GPIO controller. (There is some +optional code supporting such an implementation strategy, described later +in this document, but drivers acting as clients to the GPIO interface must +not care how it's implemented.) + +That said, if the convention is supported on their platform, drivers should +use it when possible. Platforms must select ARCH_REQUIRE_GPIOLIB or +ARCH_WANT_OPTIONAL_GPIOLIB in their Kconfig. Drivers that can't work without +standard GPIO calls should have Kconfig entries which depend on GPIOLIB. The +GPIO calls are available, either as "real code" or as optimized-away stubs, +when drivers use the include file: + + #include + +If you stick to this convention then it'll be easier for other developers to +see what your code is doing, and help maintain it. + +Note that these operations include I/O barriers on platforms which need to +use them; drivers don't need to add them explicitly. + + +Identifying GPIOs +----------------- +GPIOs are identified by unsigned integers in the range 0..MAX_INT. That +reserves "negative" numbers for other purposes like marking signals as +"not available on this board", or indicating faults. Code that doesn't +touch the underlying hardware treats these integers as opaque cookies. + +Platforms define how they use those integers, and usually #define symbols +for the GPIO lines so that board-specific setup code directly corresponds +to the relevant schematics. In contrast, drivers should only use GPIO +numbers passed to them from that setup code, using platform_data to hold +board-specific pin configuration data (along with other board specific +data they need). That avoids portability problems. + +So for example one platform uses numbers 32-159 for GPIOs; while another +uses numbers 0..63 with one set of GPIO controllers, 64-79 with another +type of GPIO controller, and on one particular board 80-95 with an FPGA. +The numbers need not be contiguous; either of those platforms could also +use numbers 2000-2063 to identify GPIOs in a bank of I2C GPIO expanders. + +If you want to initialize a structure with an invalid GPIO number, use +some negative number (perhaps "-EINVAL"); that will never be valid. To +test if such number from such a structure could reference a GPIO, you +may use this predicate: + + int gpio_is_valid(int number); + +A number that's not valid will be rejected by calls which may request +or free GPIOs (see below). Other numbers may also be rejected; for +example, a number might be valid but temporarily unused on a given board. + +Whether a platform supports multiple GPIO controllers is a platform-specific +implementation issue, as are whether that support can leave "holes" in the space +of GPIO numbers, and whether new controllers can be added at runtime. Such issues +can affect things including whether adjacent GPIO numbers are both valid. + +Using GPIOs +----------- +The first thing a system should do with a GPIO is allocate it, using +the gpio_request() call; see later. + +One of the next things to do with a GPIO, often in board setup code when +setting up a platform_device using the GPIO, is mark its direction: + + /* set as input or output, returning 0 or negative errno */ + int gpio_direction_input(unsigned gpio); + int gpio_direction_output(unsigned gpio, int value); + +The return value is zero for success, else a negative errno. It should +be checked, since the get/set calls don't have error returns and since +misconfiguration is possible. You should normally issue these calls from +a task context. However, for spinlock-safe GPIOs it's OK to use them +before tasking is enabled, as part of early board setup. + +For output GPIOs, the value provided becomes the initial output value. +This helps avoid signal glitching during system startup. + +For compatibility with legacy interfaces to GPIOs, setting the direction +of a GPIO implicitly requests that GPIO (see below) if it has not been +requested already. That compatibility is being removed from the optional +gpiolib framework. + +Setting the direction can fail if the GPIO number is invalid, or when +that particular GPIO can't be used in that mode. It's generally a bad +idea to rely on boot firmware to have set the direction correctly, since +it probably wasn't validated to do more than boot Linux. (Similarly, +that board setup code probably needs to multiplex that pin as a GPIO, +and configure pullups/pulldowns appropriately.) + + +Spinlock-Safe GPIO access +------------------------- +Most GPIO controllers can be accessed with memory read/write instructions. +Those don't need to sleep, and can safely be done from inside hard +(nonthreaded) IRQ handlers and similar contexts. + +Use the following calls to access such GPIOs, +for which gpio_cansleep() will always return false (see below): + + /* GPIO INPUT: return zero or nonzero */ + int gpio_get_value(unsigned gpio); + + /* GPIO OUTPUT */ + void gpio_set_value(unsigned gpio, int value); + +The values are boolean, zero for low, nonzero for high. When reading the +value of an output pin, the value returned should be what's seen on the +pin ... that won't always match the specified output value, because of +issues including open-drain signaling and output latencies. + +The get/set calls have no error returns because "invalid GPIO" should have +been reported earlier from gpio_direction_*(). However, note that not all +platforms can read the value of output pins; those that can't should always +return zero. Also, using these calls for GPIOs that can't safely be accessed +without sleeping (see below) is an error. + +Platform-specific implementations are encouraged to optimize the two +calls to access the GPIO value in cases where the GPIO number (and for +output, value) are constant. It's normal for them to need only a couple +of instructions in such cases (reading or writing a hardware register), +and not to need spinlocks. Such optimized calls can make bitbanging +applications a lot more efficient (in both space and time) than spending +dozens of instructions on subroutine calls. + + +GPIO access that may sleep +-------------------------- +Some GPIO controllers must be accessed using message based busses like I2C +or SPI. Commands to read or write those GPIO values require waiting to +get to the head of a queue to transmit a command and get its response. +This requires sleeping, which can't be done from inside IRQ handlers. + +Platforms that support this type of GPIO distinguish them from other GPIOs +by returning nonzero from this call (which requires a valid GPIO number, +which should have been previously allocated with gpio_request): + + int gpio_cansleep(unsigned gpio); + +To access such GPIOs, a different set of accessors is defined: + + /* GPIO INPUT: return zero or nonzero, might sleep */ + int gpio_get_value_cansleep(unsigned gpio); + + /* GPIO OUTPUT, might sleep */ + void gpio_set_value_cansleep(unsigned gpio, int value); + + +Accessing such GPIOs requires a context which may sleep, for example +a threaded IRQ handler, and those accessors must be used instead of +spinlock-safe accessors without the cansleep() name suffix. + +Other than the fact that these accessors might sleep, and will work +on GPIOs that can't be accessed from hardIRQ handlers, these calls act +the same as the spinlock-safe calls. + + ** IN ADDITION ** calls to setup and configure such GPIOs must be made +from contexts which may sleep, since they may need to access the GPIO +controller chip too: (These setup calls are usually made from board +setup or driver probe/teardown code, so this is an easy constraint.) + + gpio_direction_input() + gpio_direction_output() + gpio_request() + +## gpio_request_one() +## gpio_request_array() +## gpio_free_array() + + gpio_free() + gpio_set_debounce() + + + +Claiming and Releasing GPIOs +---------------------------- +To help catch system configuration errors, two calls are defined. + + /* request GPIO, returning 0 or negative errno. + * non-null labels may be useful for diagnostics. + */ + int gpio_request(unsigned gpio, const char *label); + + /* release previously-claimed GPIO */ + void gpio_free(unsigned gpio); + +Passing invalid GPIO numbers to gpio_request() will fail, as will requesting +GPIOs that have already been claimed with that call. The return value of +gpio_request() must be checked. You should normally issue these calls from +a task context. However, for spinlock-safe GPIOs it's OK to request GPIOs +before tasking is enabled, as part of early board setup. + +These calls serve two basic purposes. One is marking the signals which +are actually in use as GPIOs, for better diagnostics; systems may have +several hundred potential GPIOs, but often only a dozen are used on any +given board. Another is to catch conflicts, identifying errors when +(a) two or more drivers wrongly think they have exclusive use of that +signal, or (b) something wrongly believes it's safe to remove drivers +needed to manage a signal that's in active use. That is, requesting a +GPIO can serve as a kind of lock. + +Some platforms may also use knowledge about what GPIOs are active for +power management, such as by powering down unused chip sectors and, more +easily, gating off unused clocks. + +For GPIOs that use pins known to the pinctrl subsystem, that subsystem should +be informed of their use; a gpiolib driver's .request() operation may call +pinctrl_request_gpio(), and a gpiolib driver's .free() operation may call +pinctrl_free_gpio(). The pinctrl subsystem allows a pinctrl_request_gpio() +to succeed concurrently with a pin or pingroup being "owned" by a device for +pin multiplexing. + +Any programming of pin multiplexing hardware that is needed to route the +GPIO signal to the appropriate pin should occur within a GPIO driver's +.direction_input() or .direction_output() operations, and occur after any +setup of an output GPIO's value. This allows a glitch-free migration from a +pin's special function to GPIO. This is sometimes required when using a GPIO +to implement a workaround on signals typically driven by a non-GPIO HW block. + +Some platforms allow some or all GPIO signals to be routed to different pins. +Similarly, other aspects of the GPIO or pin may need to be configured, such as +pullup/pulldown. Platform software should arrange that any such details are +configured prior to gpio_request() being called for those GPIOs, e.g. using +the pinctrl subsystem's mapping table, so that GPIO users need not be aware +of these details. + +Also note that it's your responsibility to have stopped using a GPIO +before you free it. + +Considering in most cases GPIOs are actually configured right after they +are claimed, three additional calls are defined: + + /* request a single GPIO, with initial configuration specified by + * 'flags', identical to gpio_request() wrt other arguments and + * return value + */ + int gpio_request_one(unsigned gpio, unsigned long flags, const char *label); + + /* request multiple GPIOs in a single call + */ + int gpio_request_array(struct gpio *array, size_t num); + + /* release multiple GPIOs in a single call + */ + void gpio_free_array(struct gpio *array, size_t num); + +where 'flags' is currently defined to specify the following properties: + + * GPIOF_DIR_IN - to configure direction as input + * GPIOF_DIR_OUT - to configure direction as output + + * GPIOF_INIT_LOW - as output, set initial level to LOW + * GPIOF_INIT_HIGH - as output, set initial level to HIGH + * GPIOF_OPEN_DRAIN - gpio pin is open drain type. + * GPIOF_OPEN_SOURCE - gpio pin is open source type. + + * GPIOF_EXPORT_DIR_FIXED - export gpio to sysfs, keep direction + * GPIOF_EXPORT_DIR_CHANGEABLE - also export, allow changing direction + +since GPIOF_INIT_* are only valid when configured as output, so group valid +combinations as: + + * GPIOF_IN - configure as input + * GPIOF_OUT_INIT_LOW - configured as output, initial level LOW + * GPIOF_OUT_INIT_HIGH - configured as output, initial level HIGH + +When setting the flag as GPIOF_OPEN_DRAIN then it will assume that pins is +open drain type. Such pins will not be driven to 1 in output mode. It is +require to connect pull-up on such pins. By enabling this flag, gpio lib will +make the direction to input when it is asked to set value of 1 in output mode +to make the pin HIGH. The pin is make to LOW by driving value 0 in output mode. + +When setting the flag as GPIOF_OPEN_SOURCE then it will assume that pins is +open source type. Such pins will not be driven to 0 in output mode. It is +require to connect pull-down on such pin. By enabling this flag, gpio lib will +make the direction to input when it is asked to set value of 0 in output mode +to make the pin LOW. The pin is make to HIGH by driving value 1 in output mode. + +In the future, these flags can be extended to support more properties. + +Further more, to ease the claim/release of multiple GPIOs, 'struct gpio' is +introduced to encapsulate all three fields as: + + struct gpio { + unsigned gpio; + unsigned long flags; + const char *label; + }; + +A typical example of usage: + + static struct gpio leds_gpios[] = { + { 32, GPIOF_OUT_INIT_HIGH, "Power LED" }, /* default to ON */ + { 33, GPIOF_OUT_INIT_LOW, "Green LED" }, /* default to OFF */ + { 34, GPIOF_OUT_INIT_LOW, "Red LED" }, /* default to OFF */ + { 35, GPIOF_OUT_INIT_LOW, "Blue LED" }, /* default to OFF */ + { ... }, + }; + + err = gpio_request_one(31, GPIOF_IN, "Reset Button"); + if (err) + ... + + err = gpio_request_array(leds_gpios, ARRAY_SIZE(leds_gpios)); + if (err) + ... + + gpio_free_array(leds_gpios, ARRAY_SIZE(leds_gpios)); + + +GPIOs mapped to IRQs +-------------------- +GPIO numbers are unsigned integers; so are IRQ numbers. These make up +two logically distinct namespaces (GPIO 0 need not use IRQ 0). You can +map between them using calls like: + + /* map GPIO numbers to IRQ numbers */ + int gpio_to_irq(unsigned gpio); + + /* map IRQ numbers to GPIO numbers (avoid using this) */ + int irq_to_gpio(unsigned irq); + +Those return either the corresponding number in the other namespace, or +else a negative errno code if the mapping can't be done. (For example, +some GPIOs can't be used as IRQs.) It is an unchecked error to use a GPIO +number that wasn't set up as an input using gpio_direction_input(), or +to use an IRQ number that didn't originally come from gpio_to_irq(). + +These two mapping calls are expected to cost on the order of a single +addition or subtraction. They're not allowed to sleep. + +Non-error values returned from gpio_to_irq() can be passed to request_irq() +or free_irq(). They will often be stored into IRQ resources for platform +devices, by the board-specific initialization code. Note that IRQ trigger +options are part of the IRQ interface, e.g. IRQF_TRIGGER_FALLING, as are +system wakeup capabilities. + +Non-error values returned from irq_to_gpio() would most commonly be used +with gpio_get_value(), for example to initialize or update driver state +when the IRQ is edge-triggered. Note that some platforms don't support +this reverse mapping, so you should avoid using it. + + +Emulating Open Drain Signals +---------------------------- +Sometimes shared signals need to use "open drain" signaling, where only the +low signal level is actually driven. (That term applies to CMOS transistors; +"open collector" is used for TTL.) A pullup resistor causes the high signal +level. This is sometimes called a "wire-AND"; or more practically, from the +negative logic (low=true) perspective this is a "wire-OR". + +One common example of an open drain signal is a shared active-low IRQ line. +Also, bidirectional data bus signals sometimes use open drain signals. + +Some GPIO controllers directly support open drain outputs; many don't. When +you need open drain signaling but your hardware doesn't directly support it, +there's a common idiom you can use to emulate it with any GPIO pin that can +be used as either an input or an output: + + LOW: gpio_direction_output(gpio, 0) ... this drives the signal + and overrides the pullup. + + HIGH: gpio_direction_input(gpio) ... this turns off the output, + so the pullup (or some other device) controls the signal. + +If you are "driving" the signal high but gpio_get_value(gpio) reports a low +value (after the appropriate rise time passes), you know some other component +is driving the shared signal low. That's not necessarily an error. As one +common example, that's how I2C clocks are stretched: a slave that needs a +slower clock delays the rising edge of SCK, and the I2C master adjusts its +signaling rate accordingly. + + +GPIO controllers and the pinctrl subsystem +------------------------------------------ + +A GPIO controller on a SOC might be tightly coupled with the pinctrl +subsystem, in the sense that the pins can be used by other functions +together with an optional gpio feature. We have already covered the +case where e.g. a GPIO controller need to reserve a pin or set the +direction of a pin by calling any of: + +pinctrl_request_gpio() +pinctrl_free_gpio() +pinctrl_gpio_direction_input() +pinctrl_gpio_direction_output() + +But how does the pin control subsystem cross-correlate the GPIO +numbers (which are a global business) to a certain pin on a certain +pin controller? + +This is done by registering "ranges" of pins, which are essentially +cross-reference tables. These are described in +Documentation/pinctrl.txt + +While the pin allocation is totally managed by the pinctrl subsystem, +gpio (under gpiolib) is still maintained by gpio drivers. It may happen +that different pin ranges in a SoC is managed by different gpio drivers. + +This makes it logical to let gpio drivers announce their pin ranges to +the pin ctrl subsystem before it will call 'pinctrl_request_gpio' in order +to request the corresponding pin to be prepared by the pinctrl subsystem +before any gpio usage. + +For this, the gpio controller can register its pin range with pinctrl +subsystem. There are two ways of doing it currently: with or without DT. + +For with DT support refer to Documentation/devicetree/bindings/gpio/gpio.txt. + +For non-DT support, user can call gpiochip_add_pin_range() with appropriate +parameters to register a range of gpio pins with a pinctrl driver. For this +exact name string of pinctrl device has to be passed as one of the +argument to this routine. + + +What do these conventions omit? +=============================== +One of the biggest things these conventions omit is pin multiplexing, since +this is highly chip-specific and nonportable. One platform might not need +explicit multiplexing; another might have just two options for use of any +given pin; another might have eight options per pin; another might be able +to route a given GPIO to any one of several pins. (Yes, those examples all +come from systems that run Linux today.) + +Related to multiplexing is configuration and enabling of the pullups or +pulldowns integrated on some platforms. Not all platforms support them, +or support them in the same way; and any given board might use external +pullups (or pulldowns) so that the on-chip ones should not be used. +(When a circuit needs 5 kOhm, on-chip 100 kOhm resistors won't do.) +Likewise drive strength (2 mA vs 20 mA) and voltage (1.8V vs 3.3V) is a +platform-specific issue, as are models like (not) having a one-to-one +correspondence between configurable pins and GPIOs. + +There are other system-specific mechanisms that are not specified here, +like the aforementioned options for input de-glitching and wire-OR output. +Hardware may support reading or writing GPIOs in gangs, but that's usually +configuration dependent: for GPIOs sharing the same bank. (GPIOs are +commonly grouped in banks of 16 or 32, with a given SOC having several such +banks.) Some systems can trigger IRQs from output GPIOs, or read values +from pins not managed as GPIOs. Code relying on such mechanisms will +necessarily be nonportable. + +Dynamic definition of GPIOs is not currently standard; for example, as +a side effect of configuring an add-on board with some GPIO expanders. + + +GPIO implementor's framework (OPTIONAL) +======================================= +As noted earlier, there is an optional implementation framework making it +easier for platforms to support different kinds of GPIO controller using +the same programming interface. This framework is called "gpiolib". + +As a debugging aid, if debugfs is available a /sys/kernel/debug/gpio file +will be found there. That will list all the controllers registered through +this framework, and the state of the GPIOs currently in use. + + +Controller Drivers: gpio_chip +----------------------------- +In this framework each GPIO controller is packaged as a "struct gpio_chip" +with information common to each controller of that type: + + - methods to establish GPIO direction + - methods used to access GPIO values + - flag saying whether calls to its methods may sleep + - optional debugfs dump method (showing extra state like pullup config) + - label for diagnostics + +There is also per-instance data, which may come from device.platform_data: +the number of its first GPIO, and how many GPIOs it exposes. + +The code implementing a gpio_chip should support multiple instances of the +controller, possibly using the driver model. That code will configure each +gpio_chip and issue gpiochip_add(). Removing a GPIO controller should be +rare; use gpiochip_remove() when it is unavoidable. + +Most often a gpio_chip is part of an instance-specific structure with state +not exposed by the GPIO interfaces, such as addressing, power management, +and more. Chips such as codecs will have complex non-GPIO state. + +Any debugfs dump method should normally ignore signals which haven't been +requested as GPIOs. They can use gpiochip_is_requested(), which returns +either NULL or the label associated with that GPIO when it was requested. + + +Platform Support +---------------- +To support this framework, a platform's Kconfig will "select" either +ARCH_REQUIRE_GPIOLIB or ARCH_WANT_OPTIONAL_GPIOLIB +and arrange that its includes and defines +three functions: gpio_get_value(), gpio_set_value(), and gpio_cansleep(). + +It may also provide a custom value for ARCH_NR_GPIOS, so that it better +reflects the number of GPIOs in actual use on that platform, without +wasting static table space. (It should count both built-in/SoC GPIOs and +also ones on GPIO expanders. + +ARCH_REQUIRE_GPIOLIB means that the gpiolib code will always get compiled +into the kernel on that architecture. + +ARCH_WANT_OPTIONAL_GPIOLIB means the gpiolib code defaults to off and the user +can enable it and build it into the kernel optionally. + +If neither of these options are selected, the platform does not support +GPIOs through GPIO-lib and the code cannot be enabled by the user. + +Trivial implementations of those functions can directly use framework +code, which always dispatches through the gpio_chip: + + #define gpio_get_value __gpio_get_value + #define gpio_set_value __gpio_set_value + #define gpio_cansleep __gpio_cansleep + +Fancier implementations could instead define those as inline functions with +logic optimizing access to specific SOC-based GPIOs. For example, if the +referenced GPIO is the constant "12", getting or setting its value could +cost as little as two or three instructions, never sleeping. When such an +optimization is not possible those calls must delegate to the framework +code, costing at least a few dozen instructions. For bitbanged I/O, such +instruction savings can be significant. + +For SOCs, platform-specific code defines and registers gpio_chip instances +for each bank of on-chip GPIOs. Those GPIOs should be numbered/labeled to +match chip vendor documentation, and directly match board schematics. They +may well start at zero and go up to a platform-specific limit. Such GPIOs +are normally integrated into platform initialization to make them always be +available, from arch_initcall() or earlier; they can often serve as IRQs. + + +Board Support +------------- +For external GPIO controllers -- such as I2C or SPI expanders, ASICs, multi +function devices, FPGAs or CPLDs -- most often board-specific code handles +registering controller devices and ensures that their drivers know what GPIO +numbers to use with gpiochip_add(). Their numbers often start right after +platform-specific GPIOs. + +For example, board setup code could create structures identifying the range +of GPIOs that chip will expose, and passes them to each GPIO expander chip +using platform_data. Then the chip driver's probe() routine could pass that +data to gpiochip_add(). + +Initialization order can be important. For example, when a device relies on +an I2C-based GPIO, its probe() routine should only be called after that GPIO +becomes available. That may mean the device should not be registered until +calls for that GPIO can work. One way to address such dependencies is for +such gpio_chip controllers to provide setup() and teardown() callbacks to +board specific code; those board specific callbacks would register devices +once all the necessary resources are available, and remove them later when +the GPIO controller device becomes unavailable. + + +Sysfs Interface for Userspace (OPTIONAL) +======================================== +Platforms which use the "gpiolib" implementors framework may choose to +configure a sysfs user interface to GPIOs. This is different from the +debugfs interface, since it provides control over GPIO direction and +value instead of just showing a gpio state summary. Plus, it could be +present on production systems without debugging support. + +Given appropriate hardware documentation for the system, userspace could +know for example that GPIO #23 controls the write protect line used to +protect boot loader segments in flash memory. System upgrade procedures +may need to temporarily remove that protection, first importing a GPIO, +then changing its output state, then updating the code before re-enabling +the write protection. In normal use, GPIO #23 would never be touched, +and the kernel would have no need to know about it. + +Again depending on appropriate hardware documentation, on some systems +userspace GPIO can be used to determine system configuration data that +standard kernels won't know about. And for some tasks, simple userspace +GPIO drivers could be all that the system really needs. + +Note that standard kernel drivers exist for common "LEDs and Buttons" +GPIO tasks: "leds-gpio" and "gpio_keys", respectively. Use those +instead of talking directly to the GPIOs; they integrate with kernel +frameworks better than your userspace code could. + + +Paths in Sysfs +-------------- +There are three kinds of entry in /sys/class/gpio: + + - Control interfaces used to get userspace control over GPIOs; + + - GPIOs themselves; and + + - GPIO controllers ("gpio_chip" instances). + +That's in addition to standard files including the "device" symlink. + +The control interfaces are write-only: + + /sys/class/gpio/ + + "export" ... Userspace may ask the kernel to export control of + a GPIO to userspace by writing its number to this file. + + Example: "echo 19 > export" will create a "gpio19" node + for GPIO #19, if that's not requested by kernel code. + + "unexport" ... Reverses the effect of exporting to userspace. + + Example: "echo 19 > unexport" will remove a "gpio19" + node exported using the "export" file. + +GPIO signals have paths like /sys/class/gpio/gpio42/ (for GPIO #42) +and have the following read/write attributes: + + /sys/class/gpio/gpioN/ + + "direction" ... reads as either "in" or "out". This value may + normally be written. Writing as "out" defaults to + initializing the value as low. To ensure glitch free + operation, values "low" and "high" may be written to + configure the GPIO as an output with that initial value. + + Note that this attribute *will not exist* if the kernel + doesn't support changing the direction of a GPIO, or + it was exported by kernel code that didn't explicitly + allow userspace to reconfigure this GPIO's direction. + + "value" ... reads as either 0 (low) or 1 (high). If the GPIO + is configured as an output, this value may be written; + any nonzero value is treated as high. + + If the pin can be configured as interrupt-generating interrupt + and if it has been configured to generate interrupts (see the + description of "edge"), you can poll(2) on that file and + poll(2) will return whenever the interrupt was triggered. If + you use poll(2), set the events POLLPRI and POLLERR. If you + use select(2), set the file descriptor in exceptfds. After + poll(2) returns, either lseek(2) to the beginning of the sysfs + file and read the new value or close the file and re-open it + to read the value. + + "edge" ... reads as either "none", "rising", "falling", or + "both". Write these strings to select the signal edge(s) + that will make poll(2) on the "value" file return. + + This file exists only if the pin can be configured as an + interrupt generating input pin. + + "active_low" ... reads as either 0 (false) or 1 (true). Write + any nonzero value to invert the value attribute both + for reading and writing. Existing and subsequent + poll(2) support configuration via the edge attribute + for "rising" and "falling" edges will follow this + setting. + +GPIO controllers have paths like /sys/class/gpio/gpiochip42/ (for the +controller implementing GPIOs starting at #42) and have the following +read-only attributes: + + /sys/class/gpio/gpiochipN/ + + "base" ... same as N, the first GPIO managed by this chip + + "label" ... provided for diagnostics (not always unique) + + "ngpio" ... how many GPIOs this manges (N to N + ngpio - 1) + +Board documentation should in most cases cover what GPIOs are used for +what purposes. However, those numbers are not always stable; GPIOs on +a daughtercard might be different depending on the base board being used, +or other cards in the stack. In such cases, you may need to use the +gpiochip nodes (possibly in conjunction with schematics) to determine +the correct GPIO number to use for a given signal. + + +Exporting from Kernel code +-------------------------- +Kernel code can explicitly manage exports of GPIOs which have already been +requested using gpio_request(): + + /* export the GPIO to userspace */ + int gpio_export(unsigned gpio, bool direction_may_change); + + /* reverse gpio_export() */ + void gpio_unexport(); + + /* create a sysfs link to an exported GPIO node */ + int gpio_export_link(struct device *dev, const char *name, + unsigned gpio) + + /* change the polarity of a GPIO node in sysfs */ + int gpio_sysfs_set_active_low(unsigned gpio, int value); + +After a kernel driver requests a GPIO, it may only be made available in +the sysfs interface by gpio_export(). The driver can control whether the +signal direction may change. This helps drivers prevent userspace code +from accidentally clobbering important system state. + +This explicit exporting can help with debugging (by making some kinds +of experiments easier), or can provide an always-there interface that's +suitable for documenting as part of a board support package. + +After the GPIO has been exported, gpio_export_link() allows creating +symlinks from elsewhere in sysfs to the GPIO sysfs node. Drivers can +use this to provide the interface under their own device in sysfs with +a descriptive name. + +Drivers can use gpio_sysfs_set_active_low() to hide GPIO line polarity +differences between boards from user space. This only affects the +sysfs interface. Polarity change can be done both before and after +gpio_export(), and previously enabled poll(2) support for either +rising or falling edge will be reconfigured to follow this setting. diff --git a/Documentation/gpio/gpio.txt b/Documentation/gpio/gpio.txt new file mode 100644 index 000000000000..cd9b356e88cd --- /dev/null +++ b/Documentation/gpio/gpio.txt @@ -0,0 +1,119 @@ +GPIO Interfaces +=============== + +The documents in this directory give detailed instructions on how to access +GPIOs in drivers, and how to write a driver for a device that provides GPIOs +itself. + +Due to the history of GPIO interfaces in the kernel, there are two different +ways to obtain and use GPIOs: + + - The descriptor-based interface is the preferred way to manipulate GPIOs, +and is described by all the files in this directory excepted gpio-legacy.txt. + - The legacy integer-based interface which is considered deprecated (but still +usable for compatibility reasons) is documented in gpio-legacy.txt. + +The remainder of this document applies to the new descriptor-based interface. +gpio-legacy.txt contains the same information applied to the legacy +integer-based interface. + + +What is a GPIO? +=============== + +A "General Purpose Input/Output" (GPIO) is a flexible software-controlled +digital signal. They are provided from many kinds of chip, and are familiar +to Linux developers working with embedded and custom hardware. Each GPIO +represents a bit connected to a particular pin, or "ball" on Ball Grid Array +(BGA) packages. Board schematics show which external hardware connects to +which GPIOs. Drivers can be written generically, so that board setup code +passes such pin configuration data to drivers. + +System-on-Chip (SOC) processors heavily rely on GPIOs. In some cases, every +non-dedicated pin can be configured as a GPIO; and most chips have at least +several dozen of them. Programmable logic devices (like FPGAs) can easily +provide GPIOs; multifunction chips like power managers, and audio codecs +often have a few such pins to help with pin scarcity on SOCs; and there are +also "GPIO Expander" chips that connect using the I2C or SPI serial buses. +Most PC southbridges have a few dozen GPIO-capable pins (with only the BIOS +firmware knowing how they're used). + +The exact capabilities of GPIOs vary between systems. Common options: + + - Output values are writable (high=1, low=0). Some chips also have + options about how that value is driven, so that for example only one + value might be driven, supporting "wire-OR" and similar schemes for the + other value (notably, "open drain" signaling). + + - Input values are likewise readable (1, 0). Some chips support readback + of pins configured as "output", which is very useful in such "wire-OR" + cases (to support bidirectional signaling). GPIO controllers may have + input de-glitch/debounce logic, sometimes with software controls. + + - Inputs can often be used as IRQ signals, often edge triggered but + sometimes level triggered. Such IRQs may be configurable as system + wakeup events, to wake the system from a low power state. + + - Usually a GPIO will be configurable as either input or output, as needed + by different product boards; single direction ones exist too. + + - Most GPIOs can be accessed while holding spinlocks, but those accessed + through a serial bus normally can't. Some systems support both types. + +On a given board each GPIO is used for one specific purpose like monitoring +MMC/SD card insertion/removal, detecting card write-protect status, driving +a LED, configuring a transceiver, bit-banging a serial bus, poking a hardware +watchdog, sensing a switch, and so on. + + +Common GPIO Properties +====================== + +These properties are met through all the other documents of the GPIO interface +and it is useful to understand them, especially if you need to define GPIO +mappings. + +Active-High and Active-Low +-------------------------- +It is natural to assume that a GPIO is "active" when its output signal is 1 +("high"), and inactive when it is 0 ("low"). However in practice the signal of a +GPIO may be inverted before is reaches its destination, or a device could decide +to have different conventions about what "active" means. Such decisions should +be transparent to device drivers, therefore it is possible to define a GPIO as +being either active-high ("1" means "active", the default) or active-low ("0" +means "active") so that drivers only need to worry about the logical signal and +not about what happens at the line level. + +Open Drain and Open Source +-------------------------- +Sometimes shared signals need to use "open drain" (where only the low signal +level is actually driven), or "open source" (where only the high signal level is +driven) signaling. That term applies to CMOS transistors; "open collector" is +used for TTL. A pullup or pulldown resistor causes the high or low signal level. +This is sometimes called a "wire-AND"; or more practically, from the negative +logic (low=true) perspective this is a "wire-OR". + +One common example of an open drain signal is a shared active-low IRQ line. +Also, bidirectional data bus signals sometimes use open drain signals. + +Some GPIO controllers directly support open drain and open source outputs; many +don't. When you need open drain signaling but your hardware doesn't directly +support it, there's a common idiom you can use to emulate it with any GPIO pin +that can be used as either an input or an output: + + LOW: gpiod_direction_output(gpio, 0) ... this drives the signal and overrides + the pullup. + + HIGH: gpiod_direction_input(gpio) ... this turns off the output, so the pullup + (or some other device) controls the signal. + +The same logic can be applied to emulate open source signaling, by driving the +high signal and configuring the GPIO as input for low. This open drain/open +source emulation can be handled transparently by the GPIO framework. + +If you are "driving" the signal high but gpiod_get_value(gpio) reports a low +value (after the appropriate rise time passes), you know some other component is +driving the shared signal low. That's not necessarily an error. As one common +example, that's how I2C clocks are stretched: a slave that needs a slower clock +delays the rising edge of SCK, and the I2C master adjusts its signaling rate +accordingly. diff --git a/Documentation/gpio/sysfs.txt b/Documentation/gpio/sysfs.txt new file mode 100644 index 000000000000..c2c3a97f8ff7 --- /dev/null +++ b/Documentation/gpio/sysfs.txt @@ -0,0 +1,155 @@ +GPIO Sysfs Interface for Userspace +================================== + +Platforms which use the "gpiolib" implementors framework may choose to +configure a sysfs user interface to GPIOs. This is different from the +debugfs interface, since it provides control over GPIO direction and +value instead of just showing a gpio state summary. Plus, it could be +present on production systems without debugging support. + +Given appropriate hardware documentation for the system, userspace could +know for example that GPIO #23 controls the write protect line used to +protect boot loader segments in flash memory. System upgrade procedures +may need to temporarily remove that protection, first importing a GPIO, +then changing its output state, then updating the code before re-enabling +the write protection. In normal use, GPIO #23 would never be touched, +and the kernel would have no need to know about it. + +Again depending on appropriate hardware documentation, on some systems +userspace GPIO can be used to determine system configuration data that +standard kernels won't know about. And for some tasks, simple userspace +GPIO drivers could be all that the system really needs. + +Note that standard kernel drivers exist for common "LEDs and Buttons" +GPIO tasks: "leds-gpio" and "gpio_keys", respectively. Use those +instead of talking directly to the GPIOs; they integrate with kernel +frameworks better than your userspace code could. + + +Paths in Sysfs +-------------- +There are three kinds of entry in /sys/class/gpio: + + - Control interfaces used to get userspace control over GPIOs; + + - GPIOs themselves; and + + - GPIO controllers ("gpio_chip" instances). + +That's in addition to standard files including the "device" symlink. + +The control interfaces are write-only: + + /sys/class/gpio/ + + "export" ... Userspace may ask the kernel to export control of + a GPIO to userspace by writing its number to this file. + + Example: "echo 19 > export" will create a "gpio19" node + for GPIO #19, if that's not requested by kernel code. + + "unexport" ... Reverses the effect of exporting to userspace. + + Example: "echo 19 > unexport" will remove a "gpio19" + node exported using the "export" file. + +GPIO signals have paths like /sys/class/gpio/gpio42/ (for GPIO #42) +and have the following read/write attributes: + + /sys/class/gpio/gpioN/ + + "direction" ... reads as either "in" or "out". This value may + normally be written. Writing as "out" defaults to + initializing the value as low. To ensure glitch free + operation, values "low" and "high" may be written to + configure the GPIO as an output with that initial value. + + Note that this attribute *will not exist* if the kernel + doesn't support changing the direction of a GPIO, or + it was exported by kernel code that didn't explicitly + allow userspace to reconfigure this GPIO's direction. + + "value" ... reads as either 0 (low) or 1 (high). If the GPIO + is configured as an output, this value may be written; + any nonzero value is treated as high. + + If the pin can be configured as interrupt-generating interrupt + and if it has been configured to generate interrupts (see the + description of "edge"), you can poll(2) on that file and + poll(2) will return whenever the interrupt was triggered. If + you use poll(2), set the events POLLPRI and POLLERR. If you + use select(2), set the file descriptor in exceptfds. After + poll(2) returns, either lseek(2) to the beginning of the sysfs + file and read the new value or close the file and re-open it + to read the value. + + "edge" ... reads as either "none", "rising", "falling", or + "both". Write these strings to select the signal edge(s) + that will make poll(2) on the "value" file return. + + This file exists only if the pin can be configured as an + interrupt generating input pin. + + "active_low" ... reads as either 0 (false) or 1 (true). Write + any nonzero value to invert the value attribute both + for reading and writing. Existing and subsequent + poll(2) support configuration via the edge attribute + for "rising" and "falling" edges will follow this + setting. + +GPIO controllers have paths like /sys/class/gpio/gpiochip42/ (for the +controller implementing GPIOs starting at #42) and have the following +read-only attributes: + + /sys/class/gpio/gpiochipN/ + + "base" ... same as N, the first GPIO managed by this chip + + "label" ... provided for diagnostics (not always unique) + + "ngpio" ... how many GPIOs this manges (N to N + ngpio - 1) + +Board documentation should in most cases cover what GPIOs are used for +what purposes. However, those numbers are not always stable; GPIOs on +a daughtercard might be different depending on the base board being used, +or other cards in the stack. In such cases, you may need to use the +gpiochip nodes (possibly in conjunction with schematics) to determine +the correct GPIO number to use for a given signal. + + +Exporting from Kernel code +-------------------------- +Kernel code can explicitly manage exports of GPIOs which have already been +requested using gpio_request(): + + /* export the GPIO to userspace */ + int gpiod_export(struct gpio_desc *desc, bool direction_may_change); + + /* reverse gpio_export() */ + void gpiod_unexport(struct gpio_desc *desc); + + /* create a sysfs link to an exported GPIO node */ + int gpiod_export_link(struct device *dev, const char *name, + struct gpio_desc *desc); + + /* change the polarity of a GPIO node in sysfs */ + int gpiod_sysfs_set_active_low(struct gpio_desc *desc, int value); + +After a kernel driver requests a GPIO, it may only be made available in +the sysfs interface by gpiod_export(). The driver can control whether the +signal direction may change. This helps drivers prevent userspace code +from accidentally clobbering important system state. + +This explicit exporting can help with debugging (by making some kinds +of experiments easier), or can provide an always-there interface that's +suitable for documenting as part of a board support package. + +After the GPIO has been exported, gpiod_export_link() allows creating +symlinks from elsewhere in sysfs to the GPIO sysfs node. Drivers can +use this to provide the interface under their own device in sysfs with +a descriptive name. + +Drivers can use gpiod_sysfs_set_active_low() to hide GPIO line polarity +differences between boards from user space. Polarity change can be done both +before and after gpiod_export(), and previously enabled poll(2) support for +either rising or falling edge will be reconfigured to follow this setting. -- cgit v1.2.3 From 9cb238c00ba5c1ddfff2c2ed6aa66c15b962e4c3 Mon Sep 17 00:00:00 2001 From: Tony Lindgren Date: Tue, 26 Nov 2013 15:50:33 -0800 Subject: mmc: omap: Fix I2C dependency and make driver usable with device tree Some features can be configured by the companion I2C chips, which may not be available at the probe time. Fix the issue by returning -EPROBE_DEFER when the MMC controller slots are not configured. While at it, let's also add minimal device tree support so omap24xx platforms can use this driver without legacy mode since we claim to support device tree for mach-omap2 based systems. Although adding the minimal device tree support is not strictly a fix, it does remove one of the last blockers for dropping a bunch of legacy platform data for mach-omap2. Cc: linux-mmc@vger.kernel.org Acked-by: Chris Ball Signed-off-by: Tony Lindgren --- Documentation/devicetree/bindings/mmc/ti-omap.txt | 54 +++++++++++++++++++++++ drivers/mmc/host/omap.c | 11 ++++- 2 files changed, 64 insertions(+), 1 deletion(-) create mode 100644 Documentation/devicetree/bindings/mmc/ti-omap.txt (limited to 'Documentation') diff --git a/Documentation/devicetree/bindings/mmc/ti-omap.txt b/Documentation/devicetree/bindings/mmc/ti-omap.txt new file mode 100644 index 000000000000..8de579969763 --- /dev/null +++ b/Documentation/devicetree/bindings/mmc/ti-omap.txt @@ -0,0 +1,54 @@ +* TI MMC host controller for OMAP1 and 2420 + +The MMC Host Controller on TI OMAP1 and 2420 family provides +an interface for MMC, SD, and SDIO types of memory cards. + +This file documents differences between the core properties described +by mmc.txt and the properties used by the omap mmc driver. + +Note that this driver will not work with omap2430 or later omaps, +please see the omap hsmmc driver for the current omaps. + +Required properties: +- compatible: Must be "ti,omap2420-mmc", for OMAP2420 controllers +- ti,hwmods: For 2420, must be "msdi", where n is controller + instance starting 1 + +Examples: + + msdi1: mmc@4809c000 { + compatible = "ti,omap2420-mmc"; + ti,hwmods = "msdi1"; + reg = <0x4809c000 0x80>; + interrupts = <83>; + dmas = <&sdma 61 &sdma 62>; + dma-names = "tx", "rx"; + }; + +* TI MMC host controller for OMAP1 and 2420 + +The MMC Host Controller on TI OMAP1 and 2420 family provides +an interface for MMC, SD, and SDIO types of memory cards. + +This file documents differences between the core properties described +by mmc.txt and the properties used by the omap mmc driver. + +Note that this driver will not work with omap2430 or later omaps, +please see the omap hsmmc driver for the current omaps. + +Required properties: +- compatible: Must be "ti,omap2420-mmc", for OMAP2420 controllers +- ti,hwmods: For 2420, must be "msdi", where n is controller + instance starting 1 + +Examples: + + msdi1: mmc@4809c000 { + compatible = "ti,omap2420-mmc"; + ti,hwmods = "msdi1"; + reg = <0x4809c000 0x80>; + interrupts = <83>; + dmas = <&sdma 61 &sdma 62>; + dma-names = "tx", "rx"; + }; + diff --git a/drivers/mmc/host/omap.c b/drivers/mmc/host/omap.c index 22995873f554..98b6b6ef7e5c 100644 --- a/drivers/mmc/host/omap.c +++ b/drivers/mmc/host/omap.c @@ -22,6 +22,7 @@ #include #include #include +#include #include #include #include @@ -1329,7 +1330,7 @@ static int mmc_omap_probe(struct platform_device *pdev) } if (pdata->nr_slots == 0) { dev_err(&pdev->dev, "no slots\n"); - return -ENXIO; + return -EPROBE_DEFER; } res = platform_get_resource(pdev, IORESOURCE_MEM, 0); @@ -1502,12 +1503,20 @@ static int mmc_omap_remove(struct platform_device *pdev) return 0; } +#if IS_BUILTIN(CONFIG_OF) +static const struct of_device_id mmc_omap_match[] = { + { .compatible = "ti,omap2420-mmc", }, + { }, +}; +#endif + static struct platform_driver mmc_omap_driver = { .probe = mmc_omap_probe, .remove = mmc_omap_remove, .driver = { .name = DRIVER_NAME, .owner = THIS_MODULE, + .of_match_table = of_match_ptr(mmc_omap_match), }, }; -- cgit v1.2.3 From 286c24028c7f2df637323e672d9aa54a07b67bde Mon Sep 17 00:00:00 2001 From: Ashutosh Dixit Date: Wed, 27 Nov 2013 08:58:40 -0800 Subject: misc: mic: Bug fix for sysfs poll usage. MIC user space daemon poll's on sysfs changes. The documentation for sysfs_poll(...) in fs/sysfs/file.c states that "Once poll/select indicates that the value has changed, you need to close and re-open the file, or seek to 0 and read again". This step was missed out earlier and resulted in the daemon spinning continuously rather than getting blocked in 'poll'. This bug was exposed by commit aea585ef8fa65163 introduced as part of sysfs changes in 3.13-rc1. A seek to 0 has been introduced to fix it. Reviewed-by: Sudeep Dutt Signed-off-by: Ashutosh Dixit Signed-off-by: Greg Kroah-Hartman --- Documentation/mic/mpssd/mpssd.c | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'Documentation') diff --git a/Documentation/mic/mpssd/mpssd.c b/Documentation/mic/mpssd/mpssd.c index 0c980ad40b17..5c7fdda56f0e 100644 --- a/Documentation/mic/mpssd/mpssd.c +++ b/Documentation/mic/mpssd/mpssd.c @@ -1412,6 +1412,12 @@ mic_config(void *arg) } do { + ret = lseek(fd, 0, SEEK_SET); + if (ret < 0) { + mpsslog("%s: Failed to seek to file start '%s': %s\n", + mic->name, pathname, strerror(errno)); + goto close_error1; + } ret = read(fd, value, sizeof(value)); if (ret < 0) { mpsslog("%s: Failed to read sysfs entry '%s': %s\n", -- cgit v1.2.3 From 1e31aa9270daab40c7aef9d5488982e3475b87ef Mon Sep 17 00:00:00 2001 From: Ashutosh Dixit Date: Wed, 27 Nov 2013 08:58:41 -0800 Subject: misc: mic: Fix user space namespace pollution from mic_common.h. Avoid declaring ALIGN() and __aligned() in include/uapi/linux/mic_common.h since they pollute user space namespace. Also, mic_aligned_size() can be simply replaced simply by sizeof() since all structures where mic_aligned_size() is used are declared using __attribute__ ((aligned(8))); -- >From mail from H Peter Anvin about this: On Fri, Nov 08, 2013 H Peter Anvin wrote: Subject: Namespace pollution in mic_common.h This puts two macros, ALIGN() and __aligned(), into arbitrary user space namespace. This really isn't safe or acceptable, especially since those symbols are highly generic. ... When these structures are forced-aligned, they will in fact have padding automatically added by the compiler to an 8-byte boundary anyway, so mic_aligned_size() does nothing. ... Reported-by: H Peter Anvin Reviewed-by: Sudeep Dutt Signed-off-by: Nikhil Rao Signed-off-by: Ashutosh Dixit Signed-off-by: Greg Kroah-Hartman --- Documentation/mic/mpssd/mpssd.c | 4 ++-- drivers/misc/mic/card/mic_virtio.c | 4 ++-- drivers/misc/mic/card/mic_virtio.h | 7 +++---- drivers/misc/mic/host/mic_virtio.c | 2 +- include/uapi/linux/mic_common.h | 26 +++++++++----------------- 5 files changed, 17 insertions(+), 26 deletions(-) (limited to 'Documentation') diff --git a/Documentation/mic/mpssd/mpssd.c b/Documentation/mic/mpssd/mpssd.c index 5c7fdda56f0e..91f9e8e4ef7b 100644 --- a/Documentation/mic/mpssd/mpssd.c +++ b/Documentation/mic/mpssd/mpssd.c @@ -313,7 +313,7 @@ static struct mic_device_desc *get_device_desc(struct mic_info *mic, int type) int i; void *dp = get_dp(mic, type); - for (i = mic_aligned_size(struct mic_bootparam); i < PAGE_SIZE; + for (i = sizeof(struct mic_bootparam); i < PAGE_SIZE; i += mic_total_desc_size(d)) { d = dp + i; @@ -520,7 +520,7 @@ static void * virtio_net(void *arg) { static __u8 vnet_hdr[2][sizeof(struct virtio_net_hdr)]; - static __u8 vnet_buf[2][MAX_NET_PKT_SIZE] __aligned(64); + static __u8 vnet_buf[2][MAX_NET_PKT_SIZE] __attribute__ ((aligned(64))); struct iovec vnet_iov[2][2] = { { { .iov_base = vnet_hdr[0], .iov_len = sizeof(vnet_hdr[0]) }, { .iov_base = vnet_buf[0], .iov_len = sizeof(vnet_buf[0]) } }, diff --git a/drivers/misc/mic/card/mic_virtio.c b/drivers/misc/mic/card/mic_virtio.c index 4dce912f9ea6..20c567b1760b 100644 --- a/drivers/misc/mic/card/mic_virtio.c +++ b/drivers/misc/mic/card/mic_virtio.c @@ -520,8 +520,8 @@ static void mic_scan_devices(struct mic_driver *mdrv, bool remove) struct device *dev; int ret; - for (i = mic_aligned_size(struct mic_bootparam); - i < MIC_DP_SIZE; i += mic_total_desc_size(d)) { + for (i = sizeof(struct mic_bootparam); i < MIC_DP_SIZE; + i += mic_total_desc_size(d)) { d = mdrv->dp + i; dc = (void __iomem *)d + mic_aligned_desc_size(d); /* diff --git a/drivers/misc/mic/card/mic_virtio.h b/drivers/misc/mic/card/mic_virtio.h index 2c5c22c93ba8..d0407ba53bb7 100644 --- a/drivers/misc/mic/card/mic_virtio.h +++ b/drivers/misc/mic/card/mic_virtio.h @@ -42,8 +42,8 @@ static inline unsigned mic_desc_size(struct mic_device_desc __iomem *desc) { - return mic_aligned_size(*desc) - + ioread8(&desc->num_vq) * mic_aligned_size(struct mic_vqconfig) + return sizeof(*desc) + + ioread8(&desc->num_vq) * sizeof(struct mic_vqconfig) + ioread8(&desc->feature_len) * 2 + ioread8(&desc->config_len); } @@ -67,8 +67,7 @@ mic_vq_configspace(struct mic_device_desc __iomem *desc) } static inline unsigned mic_total_desc_size(struct mic_device_desc __iomem *desc) { - return mic_aligned_desc_size(desc) + - mic_aligned_size(struct mic_device_ctrl); + return mic_aligned_desc_size(desc) + sizeof(struct mic_device_ctrl); } int mic_devices_init(struct mic_driver *mdrv); diff --git a/drivers/misc/mic/host/mic_virtio.c b/drivers/misc/mic/host/mic_virtio.c index 945a3d0fe227..efe8da4401e9 100644 --- a/drivers/misc/mic/host/mic_virtio.c +++ b/drivers/misc/mic/host/mic_virtio.c @@ -467,7 +467,7 @@ static int mic_copy_dp_entry(struct mic_vdev *mvdev, } /* Find the first free device page entry */ - for (i = mic_aligned_size(struct mic_bootparam); + for (i = sizeof(struct mic_bootparam); i < MIC_DP_SIZE - mic_total_desc_size(dd_config); i += mic_total_desc_size(devp)) { devp = mdev->dp + i; diff --git a/include/uapi/linux/mic_common.h b/include/uapi/linux/mic_common.h index 17e7d95e4f53..d0ec46d88d2a 100644 --- a/include/uapi/linux/mic_common.h +++ b/include/uapi/linux/mic_common.h @@ -23,12 +23,7 @@ #include -#ifndef __KERNEL__ -#define ALIGN(a, x) (((a) + (x) - 1) & ~((x) - 1)) -#define __aligned(x) __attribute__ ((aligned(x))) -#endif - -#define mic_aligned_size(x) ALIGN(sizeof(x), 8) +#define __mic_align(a, x) (((a) + (x) - 1) & ~((x) - 1)) /** * struct mic_device_desc: Virtio device information shared between the @@ -49,7 +44,7 @@ struct mic_device_desc { __u8 config_len; __u8 status; __u64 config[0]; -} __aligned(8); +} __attribute__ ((aligned(8))); /** * struct mic_device_ctrl: Per virtio device information in the device page @@ -74,7 +69,7 @@ struct mic_device_ctrl { __u8 used_address_updated; __s8 c2h_vdev_db; __s8 h2c_vdev_db; -} __aligned(8); +} __attribute__ ((aligned(8))); /** * struct mic_bootparam: Virtio device independent information in device page @@ -93,7 +88,7 @@ struct mic_bootparam { __s8 h2c_config_db; __u8 shutdown_status; __u8 shutdown_card; -} __aligned(8); +} __attribute__ ((aligned(8))); /** * struct mic_device_page: High level representation of the device page @@ -119,7 +114,7 @@ struct mic_vqconfig { __u64 address; __u64 used_address; __u16 num; -} __aligned(8); +} __attribute__ ((aligned(8))); /* * The alignment to use between consumer and producer parts of vring. @@ -173,15 +168,13 @@ struct mic_vring { int len; }; -#define mic_aligned_desc_size(d) ALIGN(mic_desc_size(d), 8) +#define mic_aligned_desc_size(d) __mic_align(mic_desc_size(d), 8) #ifndef INTEL_MIC_CARD static inline unsigned mic_desc_size(const struct mic_device_desc *desc) { - return mic_aligned_size(*desc) - + desc->num_vq * mic_aligned_size(struct mic_vqconfig) - + desc->feature_len * 2 - + desc->config_len; + return sizeof(*desc) + desc->num_vq * sizeof(struct mic_vqconfig) + + desc->feature_len * 2 + desc->config_len; } static inline struct mic_vqconfig * @@ -201,8 +194,7 @@ static inline __u8 *mic_vq_configspace(const struct mic_device_desc *desc) } static inline unsigned mic_total_desc_size(struct mic_device_desc *desc) { - return mic_aligned_desc_size(desc) + - mic_aligned_size(struct mic_device_ctrl); + return mic_aligned_desc_size(desc) + sizeof(struct mic_device_ctrl); } #endif -- cgit v1.2.3 From 173c07278763850bfee57eec442dce38855d6f13 Mon Sep 17 00:00:00 2001 From: Ashutosh Dixit Date: Wed, 27 Nov 2013 08:58:42 -0800 Subject: misc: mic: Fix endianness issues. Endianness issues are now consistent as per the documentation in host/mic_virtio.h. Sparse warnings related to endianness are also fixed. Note that the MIC driver implementation assumes that the host can be both BE or LE whereas the card is always LE. Reported-by: Fengguang Wu Reviewed-by: Sudeep Dutt Reviewed-by: Nikhil Rao Signed-off-by: Ashutosh Dixit Signed-off-by: Greg Kroah-Hartman --- Documentation/mic/mpssd/mpssd.c | 8 ++++---- drivers/misc/mic/card/mic_virtio.c | 14 +++++++------- drivers/misc/mic/host/mic_boot.c | 2 +- drivers/misc/mic/host/mic_virtio.c | 14 +++++++------- drivers/misc/mic/host/mic_x100.c | 4 ++-- include/uapi/linux/mic_common.h | 14 +++++++------- 6 files changed, 28 insertions(+), 28 deletions(-) (limited to 'Documentation') diff --git a/Documentation/mic/mpssd/mpssd.c b/Documentation/mic/mpssd/mpssd.c index 91f9e8e4ef7b..4d17487d5ad9 100644 --- a/Documentation/mic/mpssd/mpssd.c +++ b/Documentation/mic/mpssd/mpssd.c @@ -445,8 +445,8 @@ init_vr(struct mic_info *mic, int fd, int type, __func__, mic->name, vr0->va, vr0->info, vr_size, vring_size(MIC_VRING_ENTRIES, MIC_VIRTIO_RING_ALIGN)); mpsslog("magic 0x%x expected 0x%x\n", - vr0->info->magic, MIC_MAGIC + type); - assert(vr0->info->magic == MIC_MAGIC + type); + le32toh(vr0->info->magic), MIC_MAGIC + type); + assert(le32toh(vr0->info->magic) == MIC_MAGIC + type); if (vr1) { vr1->va = (struct mic_vring *) &va[MIC_DEVICE_PAGE_END + vr_size]; @@ -458,8 +458,8 @@ init_vr(struct mic_info *mic, int fd, int type, __func__, mic->name, vr1->va, vr1->info, vr_size, vring_size(MIC_VRING_ENTRIES, MIC_VIRTIO_RING_ALIGN)); mpsslog("magic 0x%x expected 0x%x\n", - vr1->info->magic, MIC_MAGIC + type + 1); - assert(vr1->info->magic == MIC_MAGIC + type + 1); + le32toh(vr1->info->magic), MIC_MAGIC + type + 1); + assert(le32toh(vr1->info->magic) == MIC_MAGIC + type + 1); } done: return va; diff --git a/drivers/misc/mic/card/mic_virtio.c b/drivers/misc/mic/card/mic_virtio.c index 20c567b1760b..ca0445fa3d83 100644 --- a/drivers/misc/mic/card/mic_virtio.c +++ b/drivers/misc/mic/card/mic_virtio.c @@ -248,17 +248,16 @@ static struct virtqueue *mic_find_vq(struct virtio_device *vdev, /* First assign the vring's allocated in host memory */ vqconfig = mic_vq_config(mvdev->desc) + index; memcpy_fromio(&config, vqconfig, sizeof(config)); - _vr_size = vring_size(config.num, MIC_VIRTIO_RING_ALIGN); + _vr_size = vring_size(le16_to_cpu(config.num), MIC_VIRTIO_RING_ALIGN); vr_size = PAGE_ALIGN(_vr_size + sizeof(struct _mic_vring_info)); - va = mic_card_map(mvdev->mdev, config.address, vr_size); + va = mic_card_map(mvdev->mdev, le64_to_cpu(config.address), vr_size); if (!va) return ERR_PTR(-ENOMEM); mvdev->vr[index] = va; memset_io(va, 0x0, _vr_size); - vq = vring_new_virtqueue(index, - config.num, MIC_VIRTIO_RING_ALIGN, vdev, - false, - va, mic_notify, callback, name); + vq = vring_new_virtqueue(index, le16_to_cpu(config.num), + MIC_VIRTIO_RING_ALIGN, vdev, false, va, + mic_notify, callback, name); if (!vq) { err = -ENOMEM; goto unmap; @@ -273,7 +272,8 @@ static struct virtqueue *mic_find_vq(struct virtio_device *vdev, /* Allocate and reassign used ring now */ mvdev->used_size[index] = PAGE_ALIGN(sizeof(__u16) * 3 + - sizeof(struct vring_used_elem) * config.num); + sizeof(struct vring_used_elem) * + le16_to_cpu(config.num)); used = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, get_order(mvdev->used_size[index])); if (!used) { diff --git a/drivers/misc/mic/host/mic_boot.c b/drivers/misc/mic/host/mic_boot.c index 7558d9186438..b75c6b5cc20f 100644 --- a/drivers/misc/mic/host/mic_boot.c +++ b/drivers/misc/mic/host/mic_boot.c @@ -62,7 +62,7 @@ void mic_bootparam_init(struct mic_device *mdev) { struct mic_bootparam *bootparam = mdev->dp; - bootparam->magic = MIC_MAGIC; + bootparam->magic = cpu_to_le32(MIC_MAGIC); bootparam->c2h_shutdown_db = mdev->shutdown_db; bootparam->h2c_shutdown_db = -1; bootparam->h2c_config_db = -1; diff --git a/drivers/misc/mic/host/mic_virtio.c b/drivers/misc/mic/host/mic_virtio.c index efe8da4401e9..453d7409da9c 100644 --- a/drivers/misc/mic/host/mic_virtio.c +++ b/drivers/misc/mic/host/mic_virtio.c @@ -293,8 +293,8 @@ static void mic_virtio_init_post(struct mic_vdev *mvdev) continue; } mvdev->mvr[i].vrh.vring.used = - mvdev->mdev->aper.va + - le64_to_cpu(vqconfig[i].used_address); + mvdev->mdev->aper.va + + le64_to_cpu(vqconfig[i].used_address); } mvdev->dc->used_address_updated = 0; @@ -525,6 +525,7 @@ int mic_virtio_add_device(struct mic_vdev *mvdev, char irqname[10]; struct mic_bootparam *bootparam = mdev->dp; u16 num; + dma_addr_t vr_addr; mutex_lock(&mdev->mic_mutex); @@ -559,17 +560,16 @@ int mic_virtio_add_device(struct mic_vdev *mvdev, } vr->len = vr_size; vr->info = vr->va + vring_size(num, MIC_VIRTIO_RING_ALIGN); - vr->info->magic = MIC_MAGIC + mvdev->virtio_id + i; - vqconfig[i].address = mic_map_single(mdev, - vr->va, vr_size); - if (mic_map_error(vqconfig[i].address)) { + vr->info->magic = cpu_to_le32(MIC_MAGIC + mvdev->virtio_id + i); + vr_addr = mic_map_single(mdev, vr->va, vr_size); + if (mic_map_error(vr_addr)) { free_pages((unsigned long)vr->va, get_order(vr_size)); ret = -ENOMEM; dev_err(mic_dev(mvdev), "%s %d err %d\n", __func__, __LINE__, ret); goto err; } - vqconfig[i].address = cpu_to_le64(vqconfig[i].address); + vqconfig[i].address = cpu_to_le64(vr_addr); vring_init(&vr->vr, num, vr->va, MIC_VIRTIO_RING_ALIGN); ret = vringh_init_kern(&mvr->vrh, diff --git a/drivers/misc/mic/host/mic_x100.c b/drivers/misc/mic/host/mic_x100.c index 81e9541b784c..0dfa8a81436e 100644 --- a/drivers/misc/mic/host/mic_x100.c +++ b/drivers/misc/mic/host/mic_x100.c @@ -397,8 +397,8 @@ mic_x100_load_ramdisk(struct mic_device *mdev) * so copy over the ramdisk @ 128M. */ memcpy_toio(mdev->aper.va + (mdev->bootaddr << 1), fw->data, fw->size); - iowrite32(cpu_to_le32(mdev->bootaddr << 1), &bp->hdr.ramdisk_image); - iowrite32(cpu_to_le32(fw->size), &bp->hdr.ramdisk_size); + iowrite32(mdev->bootaddr << 1, &bp->hdr.ramdisk_image); + iowrite32(fw->size, &bp->hdr.ramdisk_size); release_firmware(fw); error: return rc; diff --git a/include/uapi/linux/mic_common.h b/include/uapi/linux/mic_common.h index d0ec46d88d2a..6eb40244e019 100644 --- a/include/uapi/linux/mic_common.h +++ b/include/uapi/linux/mic_common.h @@ -43,7 +43,7 @@ struct mic_device_desc { __u8 feature_len; __u8 config_len; __u8 status; - __u64 config[0]; + __le64 config[0]; } __attribute__ ((aligned(8))); /** @@ -61,7 +61,7 @@ struct mic_device_desc { * @h2c_vdev_db: The doorbell number to be used by host. Set by guest. */ struct mic_device_ctrl { - __u64 vdev; + __le64 vdev; __u8 config_change; __u8 vdev_reset; __u8 guest_ack; @@ -82,7 +82,7 @@ struct mic_device_ctrl { * @shutdown_card: Set to 1 by the host when a card shutdown is initiated */ struct mic_bootparam { - __u32 magic; + __le32 magic; __s8 c2h_shutdown_db; __s8 h2c_shutdown_db; __s8 h2c_config_db; @@ -111,9 +111,9 @@ struct mic_device_page { * @num: The number of entries in the virtio_ring */ struct mic_vqconfig { - __u64 address; - __u64 used_address; - __u16 num; + __le64 address; + __le64 used_address; + __le16 num; } __attribute__ ((aligned(8))); /* @@ -149,7 +149,7 @@ struct mic_vqconfig { */ struct _mic_vring_info { __u16 avail_idx; - int magic; + __le32 magic; }; /** -- cgit v1.2.3 From dad337501d490b26fbf8d83baee99c788461c61c Mon Sep 17 00:00:00 2001 From: Dave Jones Date: Wed, 27 Nov 2013 15:15:57 -0500 Subject: remove obsolete references to powertweak This tool hasn't been maintained in over a decade, and is pretty much useless these days. Let's pretend it never happened. Also remove a long-dead email address. Signed-off-by: Dave Jones Signed-off-by: Linus Torvalds --- Documentation/Changes | 11 ----------- drivers/pci/quirks.c | 4 ---- fs/affs/Changes | 2 +- 3 files changed, 1 insertion(+), 16 deletions(-) (limited to 'Documentation') diff --git a/Documentation/Changes b/Documentation/Changes index b17580885273..07c75d18154e 100644 --- a/Documentation/Changes +++ b/Documentation/Changes @@ -196,13 +196,6 @@ chmod 0644 /dev/cpu/microcode as root before you can use this. You'll probably also want to get the user-space microcode_ctl utility to use with this. -Powertweak ----------- - -If you are running v0.1.17 or earlier, you should upgrade to -version v0.99.0 or higher. Running old versions may cause problems -with programs using shared memory. - udev ---- udev is a userspace application for populating /dev dynamically with @@ -366,10 +359,6 @@ Intel P6 microcode ------------------ o -Powertweak ----------- -o - udev ---- o diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c index b3b1b9aa8863..3a02717473ad 100644 --- a/drivers/pci/quirks.c +++ b/drivers/pci/quirks.c @@ -9,10 +9,6 @@ * * Init/reset quirks for USB host controllers should be in the * USB quirks file, where their drivers can access reuse it. - * - * The bridge optimization stuff has been removed. If you really - * have a silly BIOS which is unable to set your host bridge right, - * use the PowerTweak utility (see http://powertweak.sourceforge.net). */ #include diff --git a/fs/affs/Changes b/fs/affs/Changes index a29409c1ffe0..b41c2c9792ff 100644 --- a/fs/affs/Changes +++ b/fs/affs/Changes @@ -91,7 +91,7 @@ more 2.4 fixes: [Roman Zippel] Version 3.11 ------------ -- Converted to use 2.3.x page cache [Dave Jones ] +- Converted to use 2.3.x page cache [Dave Jones] - Corruption in truncate() bugfix [Ken Tyler ] Version 3.10 -- cgit v1.2.3 From 96d5d9d9e8b7925357737a49bdd1091543dde010 Mon Sep 17 00:00:00 2001 From: Nicolas Dichtel Date: Wed, 20 Nov 2013 09:50:28 +0100 Subject: doc: fix generation of device-drivers Since commit 7a6354e241d8 ("sched: Move wait.c into kernel/sched/"), the path of this file has changed. Signed-off-by: Nicolas Dichtel Acked-by: Randy Dunlap Acked-by: Andy Whitcroft Cc: Peter Zijlstra Cc: Ingo Molnar Signed-off-by: Linus Torvalds --- Documentation/DocBook/device-drivers.tmpl | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'Documentation') diff --git a/Documentation/DocBook/device-drivers.tmpl b/Documentation/DocBook/device-drivers.tmpl index 6c9d9d37c83a..f5170082bdb3 100644 --- a/Documentation/DocBook/device-drivers.tmpl +++ b/Documentation/DocBook/device-drivers.tmpl @@ -58,7 +58,7 @@ Wait queues and Wake events !Iinclude/linux/wait.h -!Ekernel/wait.c +!Ekernel/sched/wait.c High-resolution timers !Iinclude/linux/ktime.h -- cgit v1.2.3 From 23fd78d76415729b338ff1802a0066b4a62f7fb8 Mon Sep 17 00:00:00 2001 From: David Howells Date: Mon, 2 Dec 2013 11:24:18 +0000 Subject: KEYS: Fix multiple key add into associative array If sufficient keys (or keyrings) are added into a keyring such that a node in the associative array's tree overflows (each node has a capacity N, currently 16) and such that all N+1 keys have the same index key segment for that level of the tree (the level'th nibble of the index key), then assoc_array_insert() calls ops->diff_objects() to indicate at which bit position the two index keys vary. However, __key_link_begin() passes a NULL object to assoc_array_insert() with the intention of supplying the correct pointer later before we commit the change. This means that keyring_diff_objects() is given a NULL pointer as one of its arguments which it does not expect. This results in an oops like the attached. With the previous patch to fix the keyring hash function, this can be forced much more easily by creating a keyring and only adding keyrings to it. Add any other sort of key and a different insertion path is taken - all 16+1 objects must want to cluster in the same node slot. This can be tested by: r=`keyctl newring sandbox @s` for ((i=0; i<=16; i++)); do keyctl newring ring$i $r; done This should work fine, but oopses when the 17th keyring is added. Since ops->diff_objects() is always called with the first pointer pointing to the object to be inserted (ie. the NULL pointer), we can fix the problem by changing the to-be-inserted object pointer to point to the index key passed into assoc_array_insert() instead. Whilst we're at it, we also switch the arguments so that they are the same as for ->compare_object(). BUG: unable to handle kernel NULL pointer dereference at 0000000000000088 IP: [] hash_key_type_and_desc+0x18/0xb0 ... RIP: 0010:[] hash_key_type_and_desc+0x18/0xb0 ... Call Trace: [] keyring_diff_objects+0x21/0xd2 [] assoc_array_insert+0x3b6/0x908 [] __key_link_begin+0x78/0xe5 [] key_create_or_update+0x17d/0x36a [] SyS_add_key+0x123/0x183 [] tracesys+0xdd/0xe2 Signed-off-by: David Howells Tested-by: Stephen Gallagher --- Documentation/assoc_array.txt | 6 +++--- include/linux/assoc_array.h | 6 +++--- lib/assoc_array.c | 4 ++-- security/keys/keyring.c | 7 +++---- 4 files changed, 11 insertions(+), 12 deletions(-) (limited to 'Documentation') diff --git a/Documentation/assoc_array.txt b/Documentation/assoc_array.txt index f4faec0f66e4..2f2c6cdd73c0 100644 --- a/Documentation/assoc_array.txt +++ b/Documentation/assoc_array.txt @@ -164,10 +164,10 @@ This points to a number of methods, all of which need to be provided: (4) Diff the index keys of two objects. - int (*diff_objects)(const void *a, const void *b); + int (*diff_objects)(const void *object, const void *index_key); - Return the bit position at which the index keys of two objects differ or - -1 if they are the same. + Return the bit position at which the index key of the specified object + differs from the given index key or -1 if they are the same. (5) Free an object. diff --git a/include/linux/assoc_array.h b/include/linux/assoc_array.h index 9a193b84238a..a89df3be1686 100644 --- a/include/linux/assoc_array.h +++ b/include/linux/assoc_array.h @@ -41,10 +41,10 @@ struct assoc_array_ops { /* Is this the object we're looking for? */ bool (*compare_object)(const void *object, const void *index_key); - /* How different are two objects, to a bit position in their keys? (or - * -1 if they're the same) + /* How different is an object from an index key, to a bit position in + * their keys? (or -1 if they're the same) */ - int (*diff_objects)(const void *a, const void *b); + int (*diff_objects)(const void *object, const void *index_key); /* Method to free an object. */ void (*free_object)(void *object); diff --git a/lib/assoc_array.c b/lib/assoc_array.c index 17edeaf19180..1b6a44f1ec3e 100644 --- a/lib/assoc_array.c +++ b/lib/assoc_array.c @@ -759,8 +759,8 @@ all_leaves_cluster_together: pr_devel("all leaves cluster together\n"); diff = INT_MAX; for (i = 0; i < ASSOC_ARRAY_FAN_OUT; i++) { - int x = ops->diff_objects(assoc_array_ptr_to_leaf(edit->leaf), - assoc_array_ptr_to_leaf(node->slots[i])); + int x = ops->diff_objects(assoc_array_ptr_to_leaf(node->slots[i]), + index_key); if (x < diff) { BUG_ON(x < 0); diff = x; diff --git a/security/keys/keyring.c b/security/keys/keyring.c index 0adbc77a59b9..3dd8445cd489 100644 --- a/security/keys/keyring.c +++ b/security/keys/keyring.c @@ -279,12 +279,11 @@ static bool keyring_compare_object(const void *object, const void *data) * Compare the index keys of a pair of objects and determine the bit position * at which they differ - if they differ. */ -static int keyring_diff_objects(const void *_a, const void *_b) +static int keyring_diff_objects(const void *object, const void *data) { - const struct key *key_a = keyring_ptr_to_key(_a); - const struct key *key_b = keyring_ptr_to_key(_b); + const struct key *key_a = keyring_ptr_to_key(object); const struct keyring_index_key *a = &key_a->index_key; - const struct keyring_index_key *b = &key_b->index_key; + const struct keyring_index_key *b = data; unsigned long seg_a, seg_b; int level, i; -- cgit v1.2.3 From f04bda90392b729fea9b0420b2a87aa6f2abfcd9 Mon Sep 17 00:00:00 2001 From: Rob Herring Date: Thu, 7 Nov 2013 20:58:16 -0600 Subject: dt-bindings: add ARMv8 PMU binding Add missing "arm,armv8-pmuv3" compatible property for ARMv8 PMU. Signed-off-by: Rob Herring Cc: Will Deacon Cc: Pawel Moll Acked-by: Mark Rutland Cc: Ian Campbell --- Documentation/devicetree/bindings/arm/pmu.txt | 1 + 1 file changed, 1 insertion(+) (limited to 'Documentation') diff --git a/Documentation/devicetree/bindings/arm/pmu.txt b/Documentation/devicetree/bindings/arm/pmu.txt index 343781b9f246..3e1e498fea96 100644 --- a/Documentation/devicetree/bindings/arm/pmu.txt +++ b/Documentation/devicetree/bindings/arm/pmu.txt @@ -7,6 +7,7 @@ representation in the device tree should be done as under:- Required properties: - compatible : should be one of + "arm,armv8-pmuv3" "arm,cortex-a15-pmu" "arm,cortex-a9-pmu" "arm,cortex-a8-pmu" -- cgit v1.2.3 From f1e8e3811486b858bcc7190477bc6e4ea8f3488c Mon Sep 17 00:00:00 2001 From: Sricharan R Date: Fri, 8 Nov 2013 16:08:48 +0530 Subject: ARM: dts: doc: Document missing binding for omap5-mpu The binding and support for omap5-mpu which has a cortex-a15 smp core, gic and integrated L2 cache has been existing for sometime. So Documenting the missing binding here. Cc: Benoit Cousson Signed-off-by: Sricharan R Signed-off-by: Rob Herring --- Documentation/devicetree/bindings/arm/omap/mpu.txt | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'Documentation') diff --git a/Documentation/devicetree/bindings/arm/omap/mpu.txt b/Documentation/devicetree/bindings/arm/omap/mpu.txt index 1a5a42ce21bb..83f405bde138 100644 --- a/Documentation/devicetree/bindings/arm/omap/mpu.txt +++ b/Documentation/devicetree/bindings/arm/omap/mpu.txt @@ -7,10 +7,18 @@ The MPU contain CPUs, GIC, L2 cache and a local PRCM. Required properties: - compatible : Should be "ti,omap3-mpu" for OMAP3 Should be "ti,omap4-mpu" for OMAP4 + Should be "ti,omap5-mpu" for OMAP5 - ti,hwmods: "mpu" Examples: +- For an OMAP5 SMP system: + +mpu { + compatible = "ti,omap5-mpu"; + ti,hwmods = "mpu" +}; + - For an OMAP4 SMP system: mpu { -- cgit v1.2.3 From 21ea02686164a71f1d464835c602c3fe2a0f3d61 Mon Sep 17 00:00:00 2001 From: Fabio Estevam Date: Mon, 18 Nov 2013 11:28:07 -0200 Subject: Documentation: net: fsl-fec.txt: Add phy-supply entry phy-supply is an optional property of the fec driver, so add it to the binding documentation. Signed-off-by: Fabio Estevam Signed-off-by: Rob Herring --- Documentation/devicetree/bindings/net/fsl-fec.txt | 2 ++ 1 file changed, 2 insertions(+) (limited to 'Documentation') diff --git a/Documentation/devicetree/bindings/net/fsl-fec.txt b/Documentation/devicetree/bindings/net/fsl-fec.txt index d53639221403..845ff848d895 100644 --- a/Documentation/devicetree/bindings/net/fsl-fec.txt +++ b/Documentation/devicetree/bindings/net/fsl-fec.txt @@ -15,6 +15,7 @@ Optional properties: only if property "phy-reset-gpios" is available. Missing the property will have the duration be 1 millisecond. Numbers greater than 1000 are invalid and 1 millisecond will be used instead. +- phy-supply: regulator that powers the Ethernet PHY. Example: @@ -25,4 +26,5 @@ ethernet@83fec000 { phy-mode = "mii"; phy-reset-gpios = <&gpio2 14 0>; /* GPIO2_14 */ local-mac-address = [00 04 9F 01 1B B9]; + phy-supply = <®_fec_supply>; }; -- cgit v1.2.3 From 53d6b36020c76b7d77514ec08394a75cb9deab08 Mon Sep 17 00:00:00 2001 From: Thierry Reding Date: Mon, 18 Nov 2013 11:11:19 +0100 Subject: of: Add vendor prefix for LG Corporation Signed-off-by: Thierry Reding Signed-off-by: Rob Herring --- Documentation/devicetree/bindings/vendor-prefixes.txt | 1 + 1 file changed, 1 insertion(+) (limited to 'Documentation') diff --git a/Documentation/devicetree/bindings/vendor-prefixes.txt b/Documentation/devicetree/bindings/vendor-prefixes.txt index ce95ed1c6d3e..e986fbe26465 100644 --- a/Documentation/devicetree/bindings/vendor-prefixes.txt +++ b/Documentation/devicetree/bindings/vendor-prefixes.txt @@ -38,6 +38,7 @@ ibm International Business Machines (IBM) idt Integrated Device Technologies, Inc. img Imagination Technologies Ltd. intercontrol Inter Control Group +lg LG Corporation linux Linux-specific binding lsi LSI Corp. (LSI Logic) marvell Marvell Technology Group Ltd. -- cgit v1.2.3 From cdbea09819fc5f2ad84f1ffa218999632f0857a7 Mon Sep 17 00:00:00 2001 From: Laurent Pinchart Date: Mon, 18 Nov 2013 12:46:12 +0100 Subject: clk: exynos: Fix typos in DT bindings documentation s/comptible/compatible/ Signed-off-by: Laurent Pinchart Reviewed-by: Sachin Kamat Signed-off-by: Rob Herring --- Documentation/devicetree/bindings/clock/exynos4-clock.txt | 2 +- Documentation/devicetree/bindings/clock/exynos5250-clock.txt | 2 +- Documentation/devicetree/bindings/clock/exynos5420-clock.txt | 2 +- Documentation/devicetree/bindings/clock/exynos5440-clock.txt | 2 +- 4 files changed, 4 insertions(+), 4 deletions(-) (limited to 'Documentation') diff --git a/Documentation/devicetree/bindings/clock/exynos4-clock.txt b/Documentation/devicetree/bindings/clock/exynos4-clock.txt index c6bf8a6c8f52..a2ac2d9ac71a 100644 --- a/Documentation/devicetree/bindings/clock/exynos4-clock.txt +++ b/Documentation/devicetree/bindings/clock/exynos4-clock.txt @@ -6,7 +6,7 @@ SoC's in the Exynos4 family. Required Properties: -- comptible: should be one of the following. +- compatible: should be one of the following. - "samsung,exynos4210-clock" - controller compatible with Exynos4210 SoC. - "samsung,exynos4412-clock" - controller compatible with Exynos4412 SoC. diff --git a/Documentation/devicetree/bindings/clock/exynos5250-clock.txt b/Documentation/devicetree/bindings/clock/exynos5250-clock.txt index 24765c146e31..46f5c791ea0d 100644 --- a/Documentation/devicetree/bindings/clock/exynos5250-clock.txt +++ b/Documentation/devicetree/bindings/clock/exynos5250-clock.txt @@ -5,7 +5,7 @@ controllers within the Exynos5250 SoC. Required Properties: -- comptible: should be one of the following. +- compatible: should be one of the following. - "samsung,exynos5250-clock" - controller compatible with Exynos5250 SoC. - reg: physical base address of the controller and length of memory mapped diff --git a/Documentation/devicetree/bindings/clock/exynos5420-clock.txt b/Documentation/devicetree/bindings/clock/exynos5420-clock.txt index 32aa34ecad36..458f34789e5d 100644 --- a/Documentation/devicetree/bindings/clock/exynos5420-clock.txt +++ b/Documentation/devicetree/bindings/clock/exynos5420-clock.txt @@ -5,7 +5,7 @@ controllers within the Exynos5420 SoC. Required Properties: -- comptible: should be one of the following. +- compatible: should be one of the following. - "samsung,exynos5420-clock" - controller compatible with Exynos5420 SoC. - reg: physical base address of the controller and length of memory mapped diff --git a/Documentation/devicetree/bindings/clock/exynos5440-clock.txt b/Documentation/devicetree/bindings/clock/exynos5440-clock.txt index 4499e9966bc9..9955dc9c7d96 100644 --- a/Documentation/devicetree/bindings/clock/exynos5440-clock.txt +++ b/Documentation/devicetree/bindings/clock/exynos5440-clock.txt @@ -5,7 +5,7 @@ controllers within the Exynos5440 SoC. Required Properties: -- comptible: should be "samsung,exynos5440-clock". +- compatible: should be "samsung,exynos5440-clock". - reg: physical base address of the controller and length of memory mapped region. -- cgit v1.2.3 From dd622d2506a63f0d9cf7b3beaad12f012308a39f Mon Sep 17 00:00:00 2001 From: Wei Ni Date: Wed, 13 Nov 2013 18:59:09 +0800 Subject: of: add vendor prefix for GMT Adding Global Mixed-mode Technology Inc. to the list of devicetree vendor prefixes. Signed-off-by: Wei Ni Acked-by: Stephen Warren Reviewed-by: Jean Delvare Signed-off-by: Rob Herring --- Documentation/devicetree/bindings/vendor-prefixes.txt | 1 + 1 file changed, 1 insertion(+) (limited to 'Documentation') diff --git a/Documentation/devicetree/bindings/vendor-prefixes.txt b/Documentation/devicetree/bindings/vendor-prefixes.txt index e986fbe26465..edbb8d88c85e 100644 --- a/Documentation/devicetree/bindings/vendor-prefixes.txt +++ b/Documentation/devicetree/bindings/vendor-prefixes.txt @@ -32,6 +32,7 @@ est ESTeem Wireless Modems fsl Freescale Semiconductor GEFanuc GE Fanuc Intelligent Platforms Embedded Systems, Inc. gef GE Fanuc Intelligent Platforms Embedded Systems, Inc. +gmt Global Mixed-mode Technology, Inc. hisilicon Hisilicon Limited. hp Hewlett Packard ibm International Business Machines (IBM) -- cgit v1.2.3 From 1675088f8bc3f955e9bd31418a6b3319487f27bf Mon Sep 17 00:00:00 2001 From: Chanwoo Choi Date: Wed, 23 Oct 2013 10:44:50 +0900 Subject: hwmon: ntc_thermistor: Fix typo (pullup-uV -> pullup-uv) This patch fix typo of property name from 'pullup-uV' to 'pullup-uv'. The ntc_thermistor.c use 'pullup-uv' when parsing dt data. Signed-off-by: Chanwoo Choi Reviewed-by: Jingoo Han Acked-by: Naveen Krishna Chatradhi Reviewed-by: Tomasz Figa Signed-off-by: Rob Herring --- Documentation/devicetree/bindings/arm/samsung/exynos-adc.txt | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'Documentation') diff --git a/Documentation/devicetree/bindings/arm/samsung/exynos-adc.txt b/Documentation/devicetree/bindings/arm/samsung/exynos-adc.txt index 47ada1dff216..5d49f2b37f68 100644 --- a/Documentation/devicetree/bindings/arm/samsung/exynos-adc.txt +++ b/Documentation/devicetree/bindings/arm/samsung/exynos-adc.txt @@ -49,7 +49,7 @@ adc@12D10000 { /* NTC thermistor is a hwmon device */ ncp15wb473@0 { compatible = "ntc,ncp15wb473"; - pullup-uV = <1800000>; + pullup-uv = <1800000>; pullup-ohm = <47000>; pulldown-ohm = <0>; io-channels = <&adc 4>; -- cgit v1.2.3 From 72d944ec7eeb195db96942d5a9f907a312e23313 Mon Sep 17 00:00:00 2001 From: Stephen Warren Date: Mon, 25 Nov 2013 15:37:55 -0700 Subject: ARM: tegra: delete nvidia,tegra20-spi.txt binding This binding shouldn't exist; Tegra20 has two forms of SPI controller that are documented separately in nvidia,tegra20-sflash.txt and nvidia,tegra20-slink.txt. Signed-off-by: Stephen Warren Reviewed-by: Thierry Reding Signed-off-by: Rob Herring --- Documentation/devicetree/bindings/spi/nvidia,tegra20-spi.txt | 5 ----- 1 file changed, 5 deletions(-) delete mode 100644 Documentation/devicetree/bindings/spi/nvidia,tegra20-spi.txt (limited to 'Documentation') diff --git a/Documentation/devicetree/bindings/spi/nvidia,tegra20-spi.txt b/Documentation/devicetree/bindings/spi/nvidia,tegra20-spi.txt deleted file mode 100644 index 6b9e51896693..000000000000 --- a/Documentation/devicetree/bindings/spi/nvidia,tegra20-spi.txt +++ /dev/null @@ -1,5 +0,0 @@ -NVIDIA Tegra 2 SPI device - -Required properties: -- compatible : should be "nvidia,tegra20-spi". -- gpios : should specify GPIOs used for chipselect. -- cgit v1.2.3 From 2c0e641a963d073d60cb63c24614c642b6f64b21 Mon Sep 17 00:00:00 2001 From: Gerhard Sittig Date: Thu, 21 Nov 2013 09:41:44 +0100 Subject: dt: binding: reword PowerPC 8xxx GPIO documentation re-format and re-word the device tree binding documentation for MPC8xxx and compatibles, reference the common document for interrupt controllers and remove outdated duplicate SoC specific information Cc: Mark Rutland Cc: Rob Herring Cc: Pawel Moll Cc: Arnd Bergmann Cc: Acked-by: Arnd Bergmann Signed-off-by: Gerhard Sittig Signed-off-by: Rob Herring --- .../devicetree/bindings/gpio/8xxx_gpio.txt | 66 +++++++++++++--------- 1 file changed, 40 insertions(+), 26 deletions(-) (limited to 'Documentation') diff --git a/Documentation/devicetree/bindings/gpio/8xxx_gpio.txt b/Documentation/devicetree/bindings/gpio/8xxx_gpio.txt index b0019eb5330e..798cfc9d3839 100644 --- a/Documentation/devicetree/bindings/gpio/8xxx_gpio.txt +++ b/Documentation/devicetree/bindings/gpio/8xxx_gpio.txt @@ -5,16 +5,42 @@ This is for the non-QE/CPM/GUTs GPIO controllers as found on Every GPIO controller node must have #gpio-cells property defined, this information will be used to translate gpio-specifiers. +See bindings/gpio/gpio.txt for details of how to specify GPIO +information for devices. + +The GPIO module usually is connected to the SoC's internal interrupt +controller, see bindings/interrupt-controller/interrupts.txt (the +interrupt client nodes section) for details how to specify this GPIO +module's interrupt. + +The GPIO module may serve as another interrupt controller (cascaded to +the SoC's internal interrupt controller). See the interrupt controller +nodes section in bindings/interrupt-controller/interrupts.txt for +details. Required properties: -- compatible : "fsl,-gpio" followed by "fsl,mpc8349-gpio" for - 83xx, "fsl,mpc8572-gpio" for 85xx and "fsl,mpc8610-gpio" for 86xx. -- #gpio-cells : Should be two. The first cell is the pin number and the - second cell is used to specify optional parameters (currently unused). - - interrupts : Interrupt mapping for GPIO IRQ. - - interrupt-parent : Phandle for the interrupt controller that - services interrupts for this device. -- gpio-controller : Marks the port as GPIO controller. +- compatible: "fsl,-gpio" followed by "fsl,mpc8349-gpio" + for 83xx, "fsl,mpc8572-gpio" for 85xx, or + "fsl,mpc8610-gpio" for 86xx. +- #gpio-cells: Should be two. The first cell is the pin number + and the second cell is used to specify optional + parameters (currently unused). +- interrupt-parent: Phandle for the interrupt controller that + services interrupts for this device. +- interrupts: Interrupt mapping for GPIO IRQ. +- gpio-controller: Marks the port as GPIO controller. + +Optional properties: +- interrupt-controller: Empty boolean property which marks the GPIO + module as an IRQ controller. +- #interrupt-cells: Should be two. Defines the number of integer + cells required to specify an interrupt within + this interrupt controller. The first cell + defines the pin number, the second cell + defines additional flags (trigger type, + trigger polarity). Note that the available + set of trigger conditions supported by the + GPIO module depends on the actual SoC. Example of gpio-controller nodes for a MPC8347 SoC: @@ -22,39 +48,27 @@ Example of gpio-controller nodes for a MPC8347 SoC: #gpio-cells = <2>; compatible = "fsl,mpc8347-gpio", "fsl,mpc8349-gpio"; reg = <0xc00 0x100>; - interrupts = <74 0x8>; interrupt-parent = <&ipic>; + interrupts = <74 0x8>; gpio-controller; + interrupt-controller; + #interrupt-cells = <2>; }; gpio2: gpio-controller@d00 { #gpio-cells = <2>; compatible = "fsl,mpc8347-gpio", "fsl,mpc8349-gpio"; reg = <0xd00 0x100>; - interrupts = <75 0x8>; interrupt-parent = <&ipic>; + interrupts = <75 0x8>; gpio-controller; }; -See booting-without-of.txt for details of how to specify GPIO -information for devices. - -To use GPIO pins as interrupt sources for peripherals, specify the -GPIO controller as the interrupt parent and define GPIO number + -trigger mode using the interrupts property, which is defined like -this: - -interrupts = , where: - - number: GPIO pin (0..31) - - trigger: trigger mode: - 2 = trigger on falling edge - 3 = trigger on both edges - -Example of device using this is: +Example of a peripheral using the GPIO module as an IRQ controller: funkyfpga@0 { compatible = "funky-fpga"; ... - interrupts = <4 3>; interrupt-parent = <&gpio1>; + interrupts = <4 3>; }; -- cgit v1.2.3 From 56a39aac593a7e855bed357b1ce43eeb7a99e7e2 Mon Sep 17 00:00:00 2001 From: Alexandre Courbot Date: Sat, 23 Nov 2013 19:32:20 +0900 Subject: Documentation: gpiolib: add 00-INDEX file Give a short overview of the various GPIO documentation files. Signed-off-by: Alexandre Courbot Signed-off-by: Linus Walleij --- Documentation/gpio/00-INDEX | 14 ++++++++++++++ 1 file changed, 14 insertions(+) create mode 100644 Documentation/gpio/00-INDEX (limited to 'Documentation') diff --git a/Documentation/gpio/00-INDEX b/Documentation/gpio/00-INDEX new file mode 100644 index 000000000000..1de43ae46ae6 --- /dev/null +++ b/Documentation/gpio/00-INDEX @@ -0,0 +1,14 @@ +00-INDEX + - This file +gpio.txt + - Introduction to GPIOs and their kernel interfaces +consumer.txt + - How to obtain and use GPIOs in a driver +driver.txt + - How to write a GPIO driver +board.txt + - How to assign GPIOs to a consumer device and a function +sysfs.txt + - Information about the GPIO sysfs interface +gpio-legacy.txt + - Historical documentation of the deprecated GPIO integer interface -- cgit v1.2.3 From dd0df47dc3548bf2dfdc7b4d65f49b452a9d9701 Mon Sep 17 00:00:00 2001 From: Tony Lindgren Date: Tue, 3 Dec 2013 15:13:02 -0800 Subject: net: davinci_emac: Fix platform data handling and make usable for am3517 When booted with device tree, we may still have platform data passed as auxdata. For am3517 this is needed for passing the interrupt_enable and interrupt_disable callbacks that access the omap system control module registers. These callback functions will eventually go away when we have a separate system control module driver. Some of the things that are currently passed as platform data we don't need to set up as device tree properties as they are always the same on am3517. So let's use a new compatible flag for those so we can get those from the device tree match data. Also note that we need to fix setting of phy_dev to NULL instead of an empty string as the code later on uses that to find the first phy on the mdio bus. This seems to have been caused by 5d69e0076a72 (net: davinci_emac: switch to new mdio). Signed-off-by: Tony Lindgren Signed-off-by: David S. Miller --- .../devicetree/bindings/net/davinci_emac.txt | 2 +- drivers/net/ethernet/ti/davinci_emac.c | 26 +++++++++++++++++++++- 2 files changed, 26 insertions(+), 2 deletions(-) (limited to 'Documentation') diff --git a/Documentation/devicetree/bindings/net/davinci_emac.txt b/Documentation/devicetree/bindings/net/davinci_emac.txt index 48b259e29e87..bad381faf036 100644 --- a/Documentation/devicetree/bindings/net/davinci_emac.txt +++ b/Documentation/devicetree/bindings/net/davinci_emac.txt @@ -4,7 +4,7 @@ This file provides information, what the device node for the davinci_emac interface contains. Required properties: -- compatible: "ti,davinci-dm6467-emac"; +- compatible: "ti,davinci-dm6467-emac" or "ti,am3517-emac" - reg: Offset and length of the register set for the device - ti,davinci-ctrl-reg-offset: offset to control register - ti,davinci-ctrl-mod-reg-offset: offset to control module register diff --git a/drivers/net/ethernet/ti/davinci_emac.c b/drivers/net/ethernet/ti/davinci_emac.c index 41ba974bf37c..cd9b164a0434 100644 --- a/drivers/net/ethernet/ti/davinci_emac.c +++ b/drivers/net/ethernet/ti/davinci_emac.c @@ -61,6 +61,7 @@ #include #include #include +#include #include #include @@ -1752,10 +1753,14 @@ static const struct net_device_ops emac_netdev_ops = { #endif }; +static const struct of_device_id davinci_emac_of_match[]; + static struct emac_platform_data * davinci_emac_of_get_pdata(struct platform_device *pdev, struct emac_priv *priv) { struct device_node *np; + const struct of_device_id *match; + const struct emac_platform_data *auxdata; struct emac_platform_data *pdata = NULL; const u8 *mac_addr; @@ -1793,7 +1798,20 @@ davinci_emac_of_get_pdata(struct platform_device *pdev, struct emac_priv *priv) priv->phy_node = of_parse_phandle(np, "phy-handle", 0); if (!priv->phy_node) - pdata->phy_id = ""; + pdata->phy_id = NULL; + + auxdata = pdev->dev.platform_data; + if (auxdata) { + pdata->interrupt_enable = auxdata->interrupt_enable; + pdata->interrupt_disable = auxdata->interrupt_disable; + } + + match = of_match_device(davinci_emac_of_match, &pdev->dev); + if (match && match->data) { + auxdata = match->data; + pdata->version = auxdata->version; + pdata->hw_ram_addr = auxdata->hw_ram_addr; + } pdev->dev.platform_data = pdata; @@ -2020,8 +2038,14 @@ static const struct dev_pm_ops davinci_emac_pm_ops = { }; #if IS_ENABLED(CONFIG_OF) +static const struct emac_platform_data am3517_emac_data = { + .version = EMAC_VERSION_2, + .hw_ram_addr = 0x01e20000, +}; + static const struct of_device_id davinci_emac_of_match[] = { {.compatible = "ti,davinci-dm6467-emac", }, + {.compatible = "ti,am3517-emac", .data = &am3517_emac_data, }, {}, }; MODULE_DEVICE_TABLE(of, davinci_emac_of_match); -- cgit v1.2.3 From c1b96a236e94d49d9396d0bbceb5524519c5c66e Mon Sep 17 00:00:00 2001 From: Philipp Zabel Date: Tue, 21 May 2013 05:11:35 -0300 Subject: [media] videobuf2: Add support for file access mode flags for DMABUF exporting Currently it is not possible for userspace to map a DMABUF exported buffer with write permissions. This patch allows to also pass O_RDONLY/O_RDWR when exporting the buffer, so that userspace may map it with write permissions. Signed-off-by: Philipp Zabel Signed-off-by: Sylwester Nawrocki Signed-off-by: Mauro Carvalho Chehab --- Documentation/DocBook/media/v4l/vidioc-expbuf.xml | 8 +++++--- drivers/media/v4l2-core/videobuf2-core.c | 8 ++++---- drivers/media/v4l2-core/videobuf2-dma-contig.c | 4 ++-- include/media/videobuf2-core.h | 2 +- 4 files changed, 12 insertions(+), 10 deletions(-) (limited to 'Documentation') diff --git a/Documentation/DocBook/media/v4l/vidioc-expbuf.xml b/Documentation/DocBook/media/v4l/vidioc-expbuf.xml index e287c8fc803b..4165e7bfa4ff 100644 --- a/Documentation/DocBook/media/v4l/vidioc-expbuf.xml +++ b/Documentation/DocBook/media/v4l/vidioc-expbuf.xml @@ -73,7 +73,8 @@ range from zero to the maximal number of valid planes for the currently active format. For the single-planar API, applications must set plane to zero. Additional flags may be posted in the flags field. Refer to a manual for open() for details. -Currently only O_CLOEXEC is supported. All other fields must be set to zero. +Currently only O_CLOEXEC, O_RDONLY, O_WRONLY, and O_RDWR are supported. All +other fields must be set to zero. In the case of multi-planar API, every plane is exported separately using multiple VIDIOC_EXPBUF calls. @@ -170,8 +171,9 @@ multi-planar API. Otherwise this value must be set to zero. __u32 flags Flags for the newly created file, currently only -O_CLOEXEC is supported, refer to the manual of open() for more -details. +O_CLOEXEC , O_RDONLY, O_WRONLY +, and O_RDWR are supported, refer to the manual +of open() for more details. __s32 diff --git a/drivers/media/v4l2-core/videobuf2-core.c b/drivers/media/v4l2-core/videobuf2-core.c index b19b306c8f7f..57ba131f08ad 100644 --- a/drivers/media/v4l2-core/videobuf2-core.c +++ b/drivers/media/v4l2-core/videobuf2-core.c @@ -1824,8 +1824,8 @@ int vb2_expbuf(struct vb2_queue *q, struct v4l2_exportbuffer *eb) return -EINVAL; } - if (eb->flags & ~O_CLOEXEC) { - dprintk(1, "Queue does support only O_CLOEXEC flag\n"); + if (eb->flags & ~(O_CLOEXEC | O_ACCMODE)) { + dprintk(1, "Queue does support only O_CLOEXEC and access mode flags\n"); return -EINVAL; } @@ -1848,14 +1848,14 @@ int vb2_expbuf(struct vb2_queue *q, struct v4l2_exportbuffer *eb) vb_plane = &vb->planes[eb->plane]; - dbuf = call_memop(q, get_dmabuf, vb_plane->mem_priv); + dbuf = call_memop(q, get_dmabuf, vb_plane->mem_priv, eb->flags & O_ACCMODE); if (IS_ERR_OR_NULL(dbuf)) { dprintk(1, "Failed to export buffer %d, plane %d\n", eb->index, eb->plane); return -EINVAL; } - ret = dma_buf_fd(dbuf, eb->flags); + ret = dma_buf_fd(dbuf, eb->flags & ~O_ACCMODE); if (ret < 0) { dprintk(3, "buffer %d, plane %d failed to export (%d)\n", eb->index, eb->plane, ret); diff --git a/drivers/media/v4l2-core/videobuf2-dma-contig.c b/drivers/media/v4l2-core/videobuf2-dma-contig.c index 646f08f4f504..33d3871d1e13 100644 --- a/drivers/media/v4l2-core/videobuf2-dma-contig.c +++ b/drivers/media/v4l2-core/videobuf2-dma-contig.c @@ -393,7 +393,7 @@ static struct sg_table *vb2_dc_get_base_sgt(struct vb2_dc_buf *buf) return sgt; } -static struct dma_buf *vb2_dc_get_dmabuf(void *buf_priv) +static struct dma_buf *vb2_dc_get_dmabuf(void *buf_priv, unsigned long flags) { struct vb2_dc_buf *buf = buf_priv; struct dma_buf *dbuf; @@ -404,7 +404,7 @@ static struct dma_buf *vb2_dc_get_dmabuf(void *buf_priv) if (WARN_ON(!buf->sgt_base)) return NULL; - dbuf = dma_buf_export(buf, &vb2_dc_dmabuf_ops, buf->size, 0); + dbuf = dma_buf_export(buf, &vb2_dc_dmabuf_ops, buf->size, flags); if (IS_ERR(dbuf)) return NULL; diff --git a/include/media/videobuf2-core.h b/include/media/videobuf2-core.h index bd8218b15009..941055e9d125 100644 --- a/include/media/videobuf2-core.h +++ b/include/media/videobuf2-core.h @@ -83,7 +83,7 @@ struct vb2_fileio_data; struct vb2_mem_ops { void *(*alloc)(void *alloc_ctx, unsigned long size, gfp_t gfp_flags); void (*put)(void *buf_priv); - struct dma_buf *(*get_dmabuf)(void *buf_priv); + struct dma_buf *(*get_dmabuf)(void *buf_priv, unsigned long flags); void *(*get_userptr)(void *alloc_ctx, unsigned long vaddr, unsigned long size, int write); -- cgit v1.2.3 From 66e56cd46b93ef407c60adcac62cf33b06119d50 Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Fri, 6 Dec 2013 11:36:15 +0100 Subject: packet: fix send path when running with proto == 0 Commit e40526cb20b5 introduced a cached dev pointer, that gets hooked into register_prot_hook(), __unregister_prot_hook() to update the device used for the send path. We need to fix this up, as otherwise this will not work with sockets created with protocol = 0, plus with sll_protocol = 0 passed via sockaddr_ll when doing the bind. So instead, assign the pointer directly. The compiler can inline these helper functions automagically. While at it, also assume the cached dev fast-path as likely(), and document this variant of socket creation as it seems it is not widely used (seems not even the author of TX_RING was aware of that in his reference example [1]). Tested with reproducer from e40526cb20b5. [1] http://wiki.ipxwarzone.com/index.php5?title=Linux_packet_mmap#Example Fixes: e40526cb20b5 ("packet: fix use after free race in send path when dev is released") Signed-off-by: Daniel Borkmann Tested-by: Salam Noureddine Tested-by: Jesper Dangaard Brouer Signed-off-by: David S. Miller --- Documentation/networking/packet_mmap.txt | 10 +++++ net/packet/af_packet.c | 65 ++++++++++++++++++++------------ 2 files changed, 50 insertions(+), 25 deletions(-) (limited to 'Documentation') diff --git a/Documentation/networking/packet_mmap.txt b/Documentation/networking/packet_mmap.txt index c01223628a87..8e48e3b14227 100644 --- a/Documentation/networking/packet_mmap.txt +++ b/Documentation/networking/packet_mmap.txt @@ -123,6 +123,16 @@ Transmission process is similar to capture as shown below. [shutdown] close() --------> destruction of the transmission socket and deallocation of all associated resources. +Socket creation and destruction is also straight forward, and is done +the same way as in capturing described in the previous paragraph: + + int fd = socket(PF_PACKET, mode, 0); + +The protocol can optionally be 0 in case we only want to transmit +via this socket, which avoids an expensive call to packet_rcv(). +In this case, you also need to bind(2) the TX_RING with sll_protocol = 0 +set. Otherwise, htons(ETH_P_ALL) or any other protocol, for example. + Binding the socket to your network interface is mandatory (with zero copy) to know the header size of frames used in the circular buffer. diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c index ba2548bd85bf..88cfbc189558 100644 --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -237,6 +237,30 @@ struct packet_skb_cb { static void __fanout_unlink(struct sock *sk, struct packet_sock *po); static void __fanout_link(struct sock *sk, struct packet_sock *po); +static struct net_device *packet_cached_dev_get(struct packet_sock *po) +{ + struct net_device *dev; + + rcu_read_lock(); + dev = rcu_dereference(po->cached_dev); + if (likely(dev)) + dev_hold(dev); + rcu_read_unlock(); + + return dev; +} + +static void packet_cached_dev_assign(struct packet_sock *po, + struct net_device *dev) +{ + rcu_assign_pointer(po->cached_dev, dev); +} + +static void packet_cached_dev_reset(struct packet_sock *po) +{ + RCU_INIT_POINTER(po->cached_dev, NULL); +} + /* register_prot_hook must be invoked with the po->bind_lock held, * or from a context in which asynchronous accesses to the packet * socket is not possible (packet_create()). @@ -246,12 +270,10 @@ static void register_prot_hook(struct sock *sk) struct packet_sock *po = pkt_sk(sk); if (!po->running) { - if (po->fanout) { + if (po->fanout) __fanout_link(sk, po); - } else { + else dev_add_pack(&po->prot_hook); - rcu_assign_pointer(po->cached_dev, po->prot_hook.dev); - } sock_hold(sk); po->running = 1; @@ -270,12 +292,11 @@ static void __unregister_prot_hook(struct sock *sk, bool sync) struct packet_sock *po = pkt_sk(sk); po->running = 0; - if (po->fanout) { + + if (po->fanout) __fanout_unlink(sk, po); - } else { + else __dev_remove_pack(&po->prot_hook); - RCU_INIT_POINTER(po->cached_dev, NULL); - } __sock_put(sk); @@ -2059,19 +2080,6 @@ static int tpacket_fill_skb(struct packet_sock *po, struct sk_buff *skb, return tp_len; } -static struct net_device *packet_cached_dev_get(struct packet_sock *po) -{ - struct net_device *dev; - - rcu_read_lock(); - dev = rcu_dereference(po->cached_dev); - if (dev) - dev_hold(dev); - rcu_read_unlock(); - - return dev; -} - static int tpacket_snd(struct packet_sock *po, struct msghdr *msg) { struct sk_buff *skb; @@ -2088,7 +2096,7 @@ static int tpacket_snd(struct packet_sock *po, struct msghdr *msg) mutex_lock(&po->pg_vec_lock); - if (saddr == NULL) { + if (likely(saddr == NULL)) { dev = packet_cached_dev_get(po); proto = po->num; addr = NULL; @@ -2242,7 +2250,7 @@ static int packet_snd(struct socket *sock, * Get and verify the address. */ - if (saddr == NULL) { + if (likely(saddr == NULL)) { dev = packet_cached_dev_get(po); proto = po->num; addr = NULL; @@ -2451,6 +2459,8 @@ static int packet_release(struct socket *sock) spin_lock(&po->bind_lock); unregister_prot_hook(sk, false); + packet_cached_dev_reset(po); + if (po->prot_hook.dev) { dev_put(po->prot_hook.dev); po->prot_hook.dev = NULL; @@ -2506,14 +2516,17 @@ static int packet_do_bind(struct sock *sk, struct net_device *dev, __be16 protoc spin_lock(&po->bind_lock); unregister_prot_hook(sk, true); + po->num = protocol; po->prot_hook.type = protocol; if (po->prot_hook.dev) dev_put(po->prot_hook.dev); - po->prot_hook.dev = dev; + po->prot_hook.dev = dev; po->ifindex = dev ? dev->ifindex : 0; + packet_cached_dev_assign(po, dev); + if (protocol == 0) goto out_unlock; @@ -2626,7 +2639,8 @@ static int packet_create(struct net *net, struct socket *sock, int protocol, po = pkt_sk(sk); sk->sk_family = PF_PACKET; po->num = proto; - RCU_INIT_POINTER(po->cached_dev, NULL); + + packet_cached_dev_reset(po); sk->sk_destruct = packet_sock_destruct; sk_refcnt_debug_inc(sk); @@ -3337,6 +3351,7 @@ static int packet_notifier(struct notifier_block *this, sk->sk_error_report(sk); } if (msg == NETDEV_UNREGISTER) { + packet_cached_dev_reset(po); po->ifindex = -1; if (po->prot_hook.dev) dev_put(po->prot_hook.dev); -- cgit v1.2.3 From 83f539e1a45a07934f0da69dc545bcbde01de36c Mon Sep 17 00:00:00 2001 From: Mike Snitzer Date: Tue, 26 Nov 2013 11:03:54 -0500 Subject: dm cache: update Documentation for invalidate_cblocks's range syntax The cache target's invalidate_cblocks message allows cache block (cblock) ranges to be expressed with: - The range's value is "one past the end", so the range includes through -1. Signed-off-by: Mike Snitzer Acked-by: Joe Thornber --- Documentation/device-mapper/cache.txt | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) (limited to 'Documentation') diff --git a/Documentation/device-mapper/cache.txt b/Documentation/device-mapper/cache.txt index 274752f8bdf9..719320b5ed3f 100644 --- a/Documentation/device-mapper/cache.txt +++ b/Documentation/device-mapper/cache.txt @@ -266,10 +266,12 @@ E.g. Invalidation is removing an entry from the cache without writing it back. Cache blocks can be invalidated via the invalidate_cblocks message, which takes an arbitrary number of cblock ranges. Each cblock -must be expressed as a decimal value, in the future a variant message -that takes cblock ranges expressed in hexidecimal may be needed to -better support efficient invalidation of larger caches. The cache must -be in passthrough mode when invalidate_cblocks is used. +range's end value is "one past the end", meaning 5-10 expresses a range +of values from 5 to 9. Each cblock must be expressed as a decimal +value, in the future a variant message that takes cblock ranges +expressed in hexidecimal may be needed to better support efficient +invalidation of larger caches. The cache must be in passthrough mode +when invalidate_cblocks is used. invalidate_cblocks [|-]* -- cgit v1.2.3 From 3f823c15d53dc78b50d6f561caf36e8109df1193 Mon Sep 17 00:00:00 2001 From: Tony Lindgren Date: Wed, 11 Dec 2013 13:04:27 -0800 Subject: net: smc91x: Fix device tree based configuration so it's usable Commit 89ce376c6bdc (drivers/net: Use of_match_ptr() macro in smc91x.c) added minimal device tree support to smc91x, but it's not working on many platforms because of the lack of some key configuration bits. Fix the issue by parsing the necessary configuration like the smc911x driver is doing. As most smc91x users seem to use 16-bit access, let's default to that if no reg-io-width is specified. Cc: Nicolas Pitre Cc: Mark Rutland Cc: netdev@vger.kernel.org Cc: devicetree@vger.kernel.org Acked-by: Nishanth Menon Signed-off-by: Tony Lindgren Signed-off-by: David S. Miller --- .../devicetree/bindings/net/smsc-lan91c111.txt | 4 ++ drivers/net/ethernet/smsc/smc91x.c | 45 +++++++++++++++++----- 2 files changed, 39 insertions(+), 10 deletions(-) (limited to 'Documentation') diff --git a/Documentation/devicetree/bindings/net/smsc-lan91c111.txt b/Documentation/devicetree/bindings/net/smsc-lan91c111.txt index 953049b4248a..5a41a8658daa 100644 --- a/Documentation/devicetree/bindings/net/smsc-lan91c111.txt +++ b/Documentation/devicetree/bindings/net/smsc-lan91c111.txt @@ -8,3 +8,7 @@ Required properties: Optional properties: - phy-device : phandle to Ethernet phy - local-mac-address : Ethernet mac address to use +- reg-io-width : Mask of sizes (in bytes) of the IO accesses that + are supported on the device. Valid value for SMSC LAN91c111 are + 1, 2 or 4. If it's omitted or invalid, the size would be 2 meaning + 16-bit access only. diff --git a/drivers/net/ethernet/smsc/smc91x.c b/drivers/net/ethernet/smsc/smc91x.c index 0c9b5d94154f..8bf29eb4a5a0 100644 --- a/drivers/net/ethernet/smsc/smc91x.c +++ b/drivers/net/ethernet/smsc/smc91x.c @@ -82,6 +82,7 @@ static const char version[] = #include #include #include +#include #include #include @@ -2184,6 +2185,15 @@ static void smc_release_datacs(struct platform_device *pdev, struct net_device * } } +#if IS_BUILTIN(CONFIG_OF) +static const struct of_device_id smc91x_match[] = { + { .compatible = "smsc,lan91c94", }, + { .compatible = "smsc,lan91c111", }, + {}, +}; +MODULE_DEVICE_TABLE(of, smc91x_match); +#endif + /* * smc_init(void) * Input parameters: @@ -2198,6 +2208,7 @@ static void smc_release_datacs(struct platform_device *pdev, struct net_device * static int smc_drv_probe(struct platform_device *pdev) { struct smc91x_platdata *pd = dev_get_platdata(&pdev->dev); + const struct of_device_id *match = NULL; struct smc_local *lp; struct net_device *ndev; struct resource *res, *ires; @@ -2217,11 +2228,34 @@ static int smc_drv_probe(struct platform_device *pdev) */ lp = netdev_priv(ndev); + lp->cfg.flags = 0; if (pd) { memcpy(&lp->cfg, pd, sizeof(lp->cfg)); lp->io_shift = SMC91X_IO_SHIFT(lp->cfg.flags); - } else { + } + +#if IS_BUILTIN(CONFIG_OF) + match = of_match_device(of_match_ptr(smc91x_match), &pdev->dev); + if (match) { + struct device_node *np = pdev->dev.of_node; + u32 val; + + /* Combination of IO widths supported, default to 16-bit */ + if (!of_property_read_u32(np, "reg-io-width", &val)) { + if (val & 1) + lp->cfg.flags |= SMC91X_USE_8BIT; + if ((val == 0) || (val & 2)) + lp->cfg.flags |= SMC91X_USE_16BIT; + if (val & 4) + lp->cfg.flags |= SMC91X_USE_32BIT; + } else { + lp->cfg.flags |= SMC91X_USE_16BIT; + } + } +#endif + + if (!pd && !match) { lp->cfg.flags |= (SMC_CAN_USE_8BIT) ? SMC91X_USE_8BIT : 0; lp->cfg.flags |= (SMC_CAN_USE_16BIT) ? SMC91X_USE_16BIT : 0; lp->cfg.flags |= (SMC_CAN_USE_32BIT) ? SMC91X_USE_32BIT : 0; @@ -2370,15 +2404,6 @@ static int smc_drv_resume(struct device *dev) return 0; } -#ifdef CONFIG_OF -static const struct of_device_id smc91x_match[] = { - { .compatible = "smsc,lan91c94", }, - { .compatible = "smsc,lan91c111", }, - {}, -}; -MODULE_DEVICE_TABLE(of, smc91x_match); -#endif - static struct dev_pm_ops smc_drv_pm_ops = { .suspend = smc_drv_suspend, .resume = smc_drv_resume, -- cgit v1.2.3 From 3cafea3076423987726023235e548af1d534ff1a Mon Sep 17 00:00:00 2001 From: James Solner Date: Wed, 6 Nov 2013 12:53:36 -0600 Subject: Add Documentation/module-signing.txt file This patch adds the Documentation/module-signing.txt file that is currently missing from the Documentation directory. The init/Kconfig file references the Documentation/module-signing.txt file to explain how kernel module signing works. This patch supplies this documentation. Signed-off-by: James Solner Signed-off-by: David Howells --- Documentation/module-signing.txt | 240 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 240 insertions(+) create mode 100644 Documentation/module-signing.txt (limited to 'Documentation') diff --git a/Documentation/module-signing.txt b/Documentation/module-signing.txt new file mode 100644 index 000000000000..2b40e04d3c49 --- /dev/null +++ b/Documentation/module-signing.txt @@ -0,0 +1,240 @@ + ============================== + KERNEL MODULE SIGNING FACILITY + ============================== + +CONTENTS + + - Overview. + - Configuring module signing. + - Generating signing keys. + - Public keys in the kernel. + - Manually signing modules. + - Signed modules and stripping. + - Loading signed modules. + - Non-valid signatures and unsigned modules. + - Administering/protecting the private key. + + +======== +OVERVIEW +======== + +The kernel module signing facility cryptographically signs modules during +installation and then checks the signature upon loading the module. This +allows increased kernel security by disallowing the loading of unsigned modules +or modules signed with an invalid key. Module signing increases security by +making it harder to load a malicious module into the kernel. The module +signature checking is done by the kernel so that it is not necessary to have +trusted userspace bits. + +This facility uses X.509 ITU-T standard certificates to encode the public keys +involved. The signatures are not themselves encoded in any industrial standard +type. The facility currently only supports the RSA public key encryption +standard (though it is pluggable and permits others to be used). The possible +hash algorithms that can be used are SHA-1, SHA-224, SHA-256, SHA-384, and +SHA-512 (the algorithm is selected by data in the signature). + + +========================== +CONFIGURING MODULE SIGNING +========================== + +The module signing facility is enabled by going to the "Enable Loadable Module +Support" section of the kernel configuration and turning on + + CONFIG_MODULE_SIG "Module signature verification" + +This has a number of options available: + + (1) "Require modules to be validly signed" (CONFIG_MODULE_SIG_FORCE) + + This specifies how the kernel should deal with a module that has a + signature for which the key is not known or a module that is unsigned. + + If this is off (ie. "permissive"), then modules for which the key is not + available and modules that are unsigned are permitted, but the kernel will + be marked as being tainted. + + If this is on (ie. "restrictive"), only modules that have a valid + signature that can be verified by a public key in the kernel's possession + will be loaded. All other modules will generate an error. + + Irrespective of the setting here, if the module has a signature block that + cannot be parsed, it will be rejected out of hand. + + + (2) "Automatically sign all modules" (CONFIG_MODULE_SIG_ALL) + + If this is on then modules will be automatically signed during the + modules_install phase of a build. If this is off, then the modules must + be signed manually using: + + scripts/sign-file + + + (3) "Which hash algorithm should modules be signed with?" + + This presents a choice of which hash algorithm the installation phase will + sign the modules with: + + CONFIG_SIG_SHA1 "Sign modules with SHA-1" + CONFIG_SIG_SHA224 "Sign modules with SHA-224" + CONFIG_SIG_SHA256 "Sign modules with SHA-256" + CONFIG_SIG_SHA384 "Sign modules with SHA-384" + CONFIG_SIG_SHA512 "Sign modules with SHA-512" + + The algorithm selected here will also be built into the kernel (rather + than being a module) so that modules signed with that algorithm can have + their signatures checked without causing a dependency loop. + + +======================= +GENERATING SIGNING KEYS +======================= + +Cryptographic keypairs are required to generate and check signatures. A +private key is used to generate a signature and the corresponding public key is +used to check it. The private key is only needed during the build, after which +it can be deleted or stored securely. The public key gets built into the +kernel so that it can be used to check the signatures as the modules are +loaded. + +Under normal conditions, the kernel build will automatically generate a new +keypair using openssl if one does not exist in the files: + + signing_key.priv + signing_key.x509 + +during the building of vmlinux (the public part of the key needs to be built +into vmlinux) using parameters in the: + + x509.genkey + +file (which is also generated if it does not already exist). + +It is strongly recommended that you provide your own x509.genkey file. + +Most notably, in the x509.genkey file, the req_distinguished_name section +should be altered from the default: + + [ req_distinguished_name ] + O = Magrathea + CN = Glacier signing key + emailAddress = slartibartfast@magrathea.h2g2 + +The generated RSA key size can also be set with: + + [ req ] + default_bits = 4096 + + +It is also possible to manually generate the key private/public files using the +x509.genkey key generation configuration file in the root node of the Linux +kernel sources tree and the openssl command. The following is an example to +generate the public/private key files: + + openssl req -new -nodes -utf8 -sha256 -days 36500 -batch -x509 \ + -config x509.genkey -outform DER -out signing_key.x509 \ + -keyout signing_key.priv + + +========================= +PUBLIC KEYS IN THE KERNEL +========================= + +The kernel contains a ring of public keys that can be viewed by root. They're +in a keyring called ".system_keyring" that can be seen by: + + [root@deneb ~]# cat /proc/keys + ... + 223c7853 I------ 1 perm 1f030000 0 0 keyring .system_keyring: 1 + 302d2d52 I------ 1 perm 1f010000 0 0 asymmetri Fedora kernel signing key: d69a84e6bce3d216b979e9505b3e3ef9a7118079: X509.RSA a7118079 [] + ... + +Beyond the public key generated specifically for module signing, any file +placed in the kernel source root directory or the kernel build root directory +whose name is suffixed with ".x509" will be assumed to be an X.509 public key +and will be added to the keyring. + +Further, the architecture code may take public keys from a hardware store and +add those in also (e.g. from the UEFI key database). + +Finally, it is possible to add additional public keys by doing: + + keyctl padd asymmetric "" [.system_keyring-ID] <[key-file] + +e.g.: + + keyctl padd asymmetric "" 0x223c7853 Date: Mon, 16 Dec 2013 09:31:19 -0800 Subject: libata: disable a disk via libata.force params A user on StackExchange had a failing SSD that's soldered directly onto the motherboard of his system. The BIOS does not give any option to disable it at all, so he can't just hide it from the OS via the BIOS. The old IDE layer had hdX=noprobe override for situations like this, but that was never ported to the libata layer. This patch implements a disable flag for libata.force. Example use: libata.force=2.0:disable [v2 of the patch, removed the nodisable flag per Tejun Heo] Signed-off-by: Robin H. Johnson Signed-off-by: Tejun Heo Cc: stable@vger.kernel.org Link: http://unix.stackexchange.com/questions/102648/how-to-tell-linux-kernel-3-0-to-completely-ignore-a-failing-disk Link: http://askubuntu.com/questions/352836/how-can-i-tell-linux-kernel-to-completely-ignore-a-disk-as-if-it-was-not-even-co Link: http://superuser.com/questions/599333/how-to-disable-kernel-probing-for-drive --- Documentation/kernel-parameters.txt | 2 ++ drivers/ata/libata-core.c | 1 + 2 files changed, 3 insertions(+) (limited to 'Documentation') diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 50680a59a2ff..b9e9bd854298 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -1529,6 +1529,8 @@ bytes respectively. Such letter suffixes can also be entirely omitted. * atapi_dmadir: Enable ATAPI DMADIR bridge support + * disable: Disable this device. + If there are multiple matching configurations changing the same attribute, the last one is used. diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c index dae73efe5dbf..ff0158481d53 100644 --- a/drivers/ata/libata-core.c +++ b/drivers/ata/libata-core.c @@ -6522,6 +6522,7 @@ static int __init ata_parse_force_one(char **cur, { "norst", .lflags = ATA_LFLAG_NO_HRST | ATA_LFLAG_NO_SRST }, { "rstonce", .lflags = ATA_LFLAG_RST_ONCE }, { "atapi_dmadir", .horkage_on = ATA_HORKAGE_ATAPI_DMADIR }, + { "disable", .horkage_on = ATA_HORKAGE_DISABLE }, }; char *start = *cur, *p = *cur; char *id, *val, *endp; -- cgit v1.2.3 From 188b04d580ab7acf11eb77cb564692050c10edfe Mon Sep 17 00:00:00 2001 From: Hannes Frederic Sowa Date: Sat, 14 Dec 2013 04:42:13 +0100 Subject: ipv4: improve documentation of ip_no_pmtu_disc Signed-off-by: Hannes Frederic Sowa Signed-off-by: David S. Miller --- Documentation/networking/ip-sysctl.txt | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) (limited to 'Documentation') diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt index 3c12d9a7ed00..8a984e994e61 100644 --- a/Documentation/networking/ip-sysctl.txt +++ b/Documentation/networking/ip-sysctl.txt @@ -16,8 +16,12 @@ ip_default_ttl - INTEGER Default: 64 (as recommended by RFC1700) ip_no_pmtu_disc - BOOLEAN - Disable Path MTU Discovery. - default FALSE + Disable Path MTU Discovery. If enabled and a + fragmentation-required ICMP is received, the PMTU to this + destination will be set to min_pmtu (see below). You will need + to raise min_pmtu to the smallest interface MTU on your system + manually if you want to avoid locally generated fragments. + Default: FALSE min_pmtu - INTEGER default 552 - minimum discovered Path MTU -- cgit v1.2.3 From 12f8f4fc0314103d47f9b1cbc812597b8d893ce1 Mon Sep 17 00:00:00 2001 From: Matias Bjorling Date: Wed, 18 Dec 2013 13:41:42 +0100 Subject: null_blk: documentation Add description of module and its parameters. Signed-off-by: Matias Bjorling Signed-off-by: Jens Axboe --- Documentation/block/null_blk.txt | 71 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 71 insertions(+) create mode 100644 Documentation/block/null_blk.txt (limited to 'Documentation') diff --git a/Documentation/block/null_blk.txt b/Documentation/block/null_blk.txt new file mode 100644 index 000000000000..9e1b047fd13d --- /dev/null +++ b/Documentation/block/null_blk.txt @@ -0,0 +1,71 @@ +Null block device driver +================================================================================ + +I. Overview + +The null block device (/dev/nullb*) is used for benchmarking the various +block-layer implementations. It emulates a block device of X gigabytes in size. +The following instances are possible: + + Single-queue block-layer + - Request-based. + - Single submission queue per device. + - Implements IO scheduling algorithms (CFQ, Deadline, noop). + Multi-queue block-layer + - Request-based. + - Configurable submission queues per device. + No block-layer (Known as bio-based) + - Bio-based. IO requests are submitted directly to the device driver. + - Directly accepts bio data structure and returns them. + +All of them has a completion queue for each core in the system. + +II. Module parameters applicable for all instances: + +queue_mode=[0-2]: Default: 2-Multi-queue + Selects which block-layer the module should instantiate with. + + 0: Bio-based. + 1: Single-queue. + 2: Multi-queue. + +home_node=[0--nr_nodes]: Default: NUMA_NO_NODE + Selects what socket the data structures is allocated from. + +gb=[Size in GB]: Default: 250GB + The size of the device reported to the system. + +bs=[Block size (in bytes)]: Default: 512 bytes + The block size reported to the system. + +nr_devices=[Num. devices]: Default: 2 + Number of block devices instantiated. They are instantiated as /dev/nullb0, + etc. + +irq_mode=[0-2]: Default: Soft-irq + The completion mode used for completing IOs to the block-layer. + + 0: None. + 1: Soft-irq. Uses ipi to complete IOs across sockets. Simulates the overhead + when IOs are issued from another socket than the home the device is + connected to. + 2: Timer: Waits a specific period (completion_nsec) for each IO before + completion. + +completion_nsec=[Num. ns]: Default: 10.000ns + Combined with irq_mode=2 (timer). The time each completion event must wait. + +submit_queues=[0..nr_cpus]: + The number of submission queues attached to the device driver. If unset, it + defaults to 1 on single-queue and bio-based instances. For multi-queue, + its ignored when use_per_node_hctx module parameter is 1. + +hw_queue_depth=[0..qdepth]: Defaults: 64 + The hardware queue depth of the device. + +III: Multi-queue specific parameters + +use_per_node_hctx=[0/1]: Defaults: 1 + If 1, the multi-queue block layer is instantiated with a hardware dispatch + queue for each CPU node in the system. If 0, it is instantiated with the + number of queues defined in the submit_queues parameter. -- cgit v1.2.3 From 89ed05eea093d4c18df5d504d104f29b874fea29 Mon Sep 17 00:00:00 2001 From: Matias Bjørling Date: Sat, 21 Dec 2013 00:10:59 +0100 Subject: null_blk: corrections to documentation Randy Dunlap reported a couple of grammar errors and unfortunate usages of socket/node/core. Signed-off-by: Matias Bjorling Acked-by: Randy Dunlap Signed-off-by: Jens Axboe --- Documentation/block/null_blk.txt | 20 ++++++++++---------- 1 file changed, 10 insertions(+), 10 deletions(-) (limited to 'Documentation') diff --git a/Documentation/block/null_blk.txt b/Documentation/block/null_blk.txt index 9e1b047fd13d..5603dad5534b 100644 --- a/Documentation/block/null_blk.txt +++ b/Documentation/block/null_blk.txt @@ -18,7 +18,7 @@ The following instances are possible: - Bio-based. IO requests are submitted directly to the device driver. - Directly accepts bio data structure and returns them. -All of them has a completion queue for each core in the system. +All of them have a completion queue for each core in the system. II. Module parameters applicable for all instances: @@ -30,7 +30,7 @@ queue_mode=[0-2]: Default: 2-Multi-queue 2: Multi-queue. home_node=[0--nr_nodes]: Default: NUMA_NO_NODE - Selects what socket the data structures is allocated from. + Selects what CPU node the data structures are allocated from. gb=[Size in GB]: Default: 250GB The size of the device reported to the system. @@ -38,34 +38,34 @@ gb=[Size in GB]: Default: 250GB bs=[Block size (in bytes)]: Default: 512 bytes The block size reported to the system. -nr_devices=[Num. devices]: Default: 2 +nr_devices=[Number of devices]: Default: 2 Number of block devices instantiated. They are instantiated as /dev/nullb0, etc. -irq_mode=[0-2]: Default: Soft-irq +irq_mode=[0-2]: Default: 1-Soft-irq The completion mode used for completing IOs to the block-layer. 0: None. - 1: Soft-irq. Uses ipi to complete IOs across sockets. Simulates the overhead - when IOs are issued from another socket than the home the device is + 1: Soft-irq. Uses IPI to complete IOs across CPU nodes. Simulates the overhead + when IOs are issued from another CPU node than the home the device is connected to. 2: Timer: Waits a specific period (completion_nsec) for each IO before completion. -completion_nsec=[Num. ns]: Default: 10.000ns +completion_nsec=[ns]: Default: 10.000ns Combined with irq_mode=2 (timer). The time each completion event must wait. submit_queues=[0..nr_cpus]: The number of submission queues attached to the device driver. If unset, it defaults to 1 on single-queue and bio-based instances. For multi-queue, - its ignored when use_per_node_hctx module parameter is 1. + it is ignored when use_per_node_hctx module parameter is 1. -hw_queue_depth=[0..qdepth]: Defaults: 64 +hw_queue_depth=[0..qdepth]: Default: 64 The hardware queue depth of the device. III: Multi-queue specific parameters -use_per_node_hctx=[0/1]: Defaults: 1 +use_per_node_hctx=[0/1]: Default: 1 If 1, the multi-queue block layer is instantiated with a hardware dispatch queue for each CPU node in the system. If 0, it is instantiated with the number of queues defined in the submit_queues parameter. -- cgit v1.2.3 From 200052440d3b56f593038a35b7c14bdc780184a9 Mon Sep 17 00:00:00 2001 From: Matias Bjørling Date: Sat, 21 Dec 2013 00:11:00 +0100 Subject: null_blk: set use_per_node_hctx param to false The defaults for the module is to instantiate itself with blk-mq and a submit queue for each CPU node in the system. To save resources, initialize instead with a single submit queue. Signed-off-by: Matias Bjorling Signed-off-by: Jens Axboe --- Documentation/block/null_blk.txt | 9 +++++---- drivers/block/null_blk.c | 4 ++-- 2 files changed, 7 insertions(+), 6 deletions(-) (limited to 'Documentation') diff --git a/Documentation/block/null_blk.txt b/Documentation/block/null_blk.txt index 5603dad5534b..b2830b435895 100644 --- a/Documentation/block/null_blk.txt +++ b/Documentation/block/null_blk.txt @@ -65,7 +65,8 @@ hw_queue_depth=[0..qdepth]: Default: 64 III: Multi-queue specific parameters -use_per_node_hctx=[0/1]: Default: 1 - If 1, the multi-queue block layer is instantiated with a hardware dispatch - queue for each CPU node in the system. If 0, it is instantiated with the - number of queues defined in the submit_queues parameter. +use_per_node_hctx=[0/1]: Default: 0 + 0: The number of submit queues are set to the value of the submit_queues + parameter. + 1: The multi-queue block layer is instantiated with a hardware dispatch + queue for each CPU node in the system. diff --git a/drivers/block/null_blk.c b/drivers/block/null_blk.c index 8f2e7c330d6d..9b0311b61fe1 100644 --- a/drivers/block/null_blk.c +++ b/drivers/block/null_blk.c @@ -101,9 +101,9 @@ static int hw_queue_depth = 64; module_param(hw_queue_depth, int, S_IRUGO); MODULE_PARM_DESC(hw_queue_depth, "Queue depth for each hardware queue. Default: 64"); -static bool use_per_node_hctx = true; +static bool use_per_node_hctx = false; module_param(use_per_node_hctx, bool, S_IRUGO); -MODULE_PARM_DESC(use_per_node_hctx, "Use per-node allocation for hardware context queues. Default: true"); +MODULE_PARM_DESC(use_per_node_hctx, "Use per-node allocation for hardware context queues. Default: false"); static void put_tag(struct nullb_queue *nq, unsigned int tag) { -- cgit v1.2.3