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| author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 | 
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| committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 | 
| commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
| tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /Documentation/mips | |
| download | linux-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.bz2 | |
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'Documentation/mips')
| -rw-r--r-- | Documentation/mips/GT64120.README | 65 | ||||
| -rw-r--r-- | Documentation/mips/pci/pci.README | 54 | ||||
| -rw-r--r-- | Documentation/mips/time.README | 198 | 
3 files changed, 317 insertions, 0 deletions
| diff --git a/Documentation/mips/GT64120.README b/Documentation/mips/GT64120.README new file mode 100644 index 000000000000..2d0eec91dc59 --- /dev/null +++ b/Documentation/mips/GT64120.README @@ -0,0 +1,65 @@ +README for arch/mips/gt64120 directory and subdirectories + +Jun Sun, jsun@mvista.com or jsun@junsun.net +01/27, 2001 + +MOTIVATION +---------- + +Many MIPS boards share the same system controller (or CPU companian chip), +such as GT-64120.  It is highly desirable to let these boards share +the same controller code instead of duplicating them. + +This directory is meant to hold all MIPS boards that use GT-64120 or GT-64120A. + + +HOW TO ADD A BOARD +------------------ +  +. Create a subdirectory include/asm/gt64120/<board>.   + +. Create a file called gt64120_dep.h under that directory. + +. Modify include/asm/gt64120/gt64120.h file to include the new gt64120_dep.h +  based on config options.  The board-dep section is at the end of  +  include/asm/gt64120/gt64120.h file. There you can find all required +  definitions include/asm/gt64120/<board>/gt64120_dep.h file must supply. + +. Create a subdirectory arch/mips/gt64120/<board> directory to hold +  board specific routines. + +. The GT-64120 common code is supplied under arch/mips/gt64120/common directory. +  It includes: +	1) arch/mips/gt64120/pci.c - +		common PCI routine, include the top-level pcibios_init() +	2) arch/mips/gt64120/irq.c - +		common IRQ routine, include the top-level do_IRQ()  +	   [This part really belongs to arch/mips/kernel. jsun] + 	3) arch/mips/gt64120/gt_irq.c - +		common IRQ routines for GT-64120 chip.  Currently it only handles +	 	the timer interrupt. + +. Board-specific routines are supplied under arch/mips/gt64120/<board> dir. +	1) arch/mips/gt64120/<board>/pci.c - it provides bus fixup routine +	2) arch/mips/gt64120/<board>/irq.c - it provides enable/disable irqs +		and board irq setup routine (irq_setup) +	3) arch/mips/gt64120/<board>/int-handler.S - +		The first-level interrupt dispatching routine. +	4) a bunch of other "normal" stuff (setup, prom, dbg_io, reset, etc) + +. Follow other "normal" procedure to modify configuration files, etc. + + +TO-DO LIST +---------- + +. Expand arch/mips/gt64120/gt_irq.c to handle all GT-64120 interrupts. +  We probably need to introduce GT_IRQ_BASE  in board-dep header file, +  which is used the starting irq_nr for all GT irqs. + +  A function, gt64120_handle_irq(), will be added so that the first-level +  irq dispatcher will call this function if it detects an interrupt +  from GT-64120. + +. More support for GT-64120 PCI features (2nd PCI bus, perhaps) + diff --git a/Documentation/mips/pci/pci.README b/Documentation/mips/pci/pci.README new file mode 100644 index 000000000000..8697ee41372d --- /dev/null +++ b/Documentation/mips/pci/pci.README @@ -0,0 +1,54 @@ + +Pete Popov, ppopov@pacbell.net +07/11/2001 + +This README briefly explains how to use the pci and pci_auto +code in arch/mips/kernel.  The code was ported from PowerPC and +modified slightly. It has been tested pretty well on PPC on some +rather complex systems with multiple bridges and devices behind +each bridge. However, at the time this README was written, the +mips port was tested only on boards with a single pci bus and +no P2P bridges.  It's very possible that on boards with P2P +bridges some modifications have to be made. The code will  +evolve, no doubt, but currently every single mips board +is doing its own pcibios thing and it has become a big +mess.  This generic pci code is meant to clean up the mips +pci mess and make it easier to add pci support to new boards. + +inside the define for your board in arch/mips/config.in.  +For example, the Galileo EV96100 board  looks like this: + +if [ "$CONFIG_MIPS_EV96100" = "y" ]; then +	define_bool CONFIG_PCI y +	define_bool CONFIG_MIPS_GT96100 y +	define_bool CONFIG_NEW_PCI y +	define_bool CONFIG_SWAP_IO_SPACE y +fi  + + +Next, if you want to use the arch/mips/kernel/pci code, which has the +pcibios_init() function, add + +define_bool CONFIG_NEW_PCI y +  +inside the define for your board. Again, the EV96100 example above +show NEW_PCI turned on. + + +Now you need to add your files to hook in your pci configuration +cycles.  Usually you'll need only a couple of files named something +like pci_fixups.c and pci_ops.c.  You can copy the templates +provided and fill in the code. + +The file pci_ops.c should contain the pci configuration cycles routines. +It also has the mips_pci_channels[] array which contains the descriptors +of each pci controller. + +The file pci_fixups.c contains a few routines to do interrupt fixups, +resources fixups, and, if needed, pci bios fixups. + +Usually you'll put your pci_fixups.c file in your board specific directory,  +since the functions in that file are board specific.  The functions in +pci_ops.c, on the other hand, are usually pci controller specific so that +file could be shared among a few different boards using the same +pci controller. diff --git a/Documentation/mips/time.README b/Documentation/mips/time.README new file mode 100644 index 000000000000..70bc0dd43d6d --- /dev/null +++ b/Documentation/mips/time.README @@ -0,0 +1,198 @@ +README for MIPS time services + +Jun Sun +jsun@mvista.com or jsun@junsun.net + + +ABOUT +----- +This file describes the new arch/mips/kernel/time.c, related files and the  +services they provide.  + +If you are short in patience and just want to know how to use time.c for a  +new board or convert an existing board, go to the last section. + + +FILES, COMPATABILITY AND CONFIGS +--------------------------------- + +The old arch/mips/kernel/time.c is renamed to old-time.c. + +A new time.c is put there, together with include/asm-mips/time.h. + +Two configs variables are introduced, CONFIG_OLD_TIME_C and CONFIG_NEW_TIME_C. +So we allow boards using  + +	1) old time.c (CONFIG_OLD_TIME_C) +	2) new time.c (CONFIG_NEW_TIME_C) +	3) neither (their own private time.c) + +However, it is expected every board will move to the new time.c in the near +future. + + +WHAT THE NEW CODE PROVIDES? +---------------------------  + +The new time code provide the following services: + +  a) Implements functions required by Linux common code: +	time_init +	do_gettimeofday +	do_settimeofday + +  b) provides an abstraction of RTC and null RTC implementation as default. +	extern unsigned long (*rtc_get_time)(void); +	extern int (*rtc_set_time)(unsigned long); + +  c) a set of gettimeoffset functions for different CPUs and different +     needs. + +  d) high-level and low-level timer interrupt routines where the timer  +     interrupt source  may or may not be the CPU timer.  The high-level  +     routine is dispatched through do_IRQ() while the low-level is  +     dispatched in assemably code (usually int-handler.S) + + +WHAT THE NEW CODE REQUIRES? +--------------------------- + +For the new code to work properly, each board implementation needs to supply +the following functions or values: + +  a) board_time_init - a function pointer.  Invoked at the beginnig of +     time_init().  It is optional. +	1. (optional) set up RTC routines +	2. (optional) calibrate and set the mips_counter_frequency + +  b) board_timer_setup - a function pointer.  Invoked at the end of time_init() +	1. (optional) over-ride any decisions made in time_init() +	2. set up the irqaction for timer interrupt. +	3. enable the timer interrupt + +  c) (optional) board-specific RTC routines. + +  d) (optional) mips_counter_frequency - It must be definied if the board +     is using CPU counter for timer interrupt or it is using fixed rate +     gettimeoffset(). + + +PORTING GUIDE +------------- + +Step 1: decide how you like to implement the time services. + +  a) does this board have a RTC?  If yes, implement the two RTC funcs. + +  b) does the CPU have counter/compare registers?  + +     If the answer is no, you need a timer to provide the timer interrupt +     at 100 HZ speed. + +     You cannot use the fast gettimeoffset functions, i.e., + +	unsigned long fixed_rate_gettimeoffset(void); +	unsigned long calibrate_div32_gettimeoffset(void); +	unsigned long calibrate_div64_gettimeoffset(void); + +    You can use null_gettimeoffset() will gives the same time resolution as +    jiffy.  Or you can implement your own gettimeoffset (probably based on  +    some ad hoc hardware on your machine.) + +  c) The following sub steps assume your CPU has counter register. +     Do you plan to use the CPU counter register as the timer interrupt +     or use an exnternal timer? + +     In order to use CPU counter register as the timer interrupt source, you +     must know the counter speed (mips_counter_frequency).  It is usually the +     same as the CPU speed or an integral divisor of it. + +  d) decide on whether you want to use high-level or low-level timer +     interrupt routines.  The low-level one is presumably faster, but should +     not make too mcuh difference. + + +Step 2:  the machine setup() function + +  If you supply board_time_init(), set the function poointer. + +  Set the function pointer board_timer_setup() (mandatory) + + +Step 3: implement rtc routines, board_time_init() and board_timer_setup() +  if needed. + +  board_time_init() -  +  	a) (optional) set up RTC routines,  +        b) (optional) calibrate and set the mips_counter_frequency + 	    (only needed if you intended to use fixed_rate_gettimeoffset + 	     or use cpu counter as timer interrupt source) + +  board_timer_setup() -  + 	a) (optional) over-write any choices made above by time_init(). + 	b) machine specific code should setup the timer irqaction. + 	c) enable the timer interrupt + + +  If the RTC chip is a common chip, I suggest the routines are put under +  arch/mips/libs.  For example, for DS1386 chip, one would create +  rtc-ds1386.c under arch/mips/lib directory.  Add the following line to +  the arch/mips/lib/Makefile: + +	obj-$(CONFIG_DDB5476) += rtc-ds1386.o + +Step 4: if you are using low-level timer interrupt, change your interrupt +  dispathcing code to check for timer interrupt and jump to  +  ll_timer_interrupt() directly  if one is detected. + +Step 5: Modify arch/mips/config.in and add CONFIG_NEW_TIME_C to your machine. +  Modify the appropriate defconfig if applicable. + +Final notes:  + +For some tricky cases, you may need to add your own wrapper functions  +for some of the functions in time.c.   + +For example, you may define your own timer interrupt routine, which does +some of its own processing and then calls timer_interrupt(). + +You can also over-ride any of the built-in functions (gettimeoffset, +RTC routines and/or timer interrupt routine). + + +PORTING NOTES FOR SMP +---------------------- + +If you have a SMP box, things are slightly more complicated. + +The time service running every jiffy is logically divided into two parts: + +  1) the one for the whole system  (defined in timer_interrupt()) +  2) the one that should run for each CPU (defined in local_timer_interrupt()) + +You need to decide on your timer interrupt sources. + +  case 1) - whole system has only one timer interrupt delivered to one CPU + +	In this case, you set up timer interrupt as in UP systems.  In addtion, +	you need to set emulate_local_timer_interrupt to 1 so that other +	CPUs get to call local_timer_interrupt(). + +	THIS IS CURRENTLY NOT IMPLEMNETED.  However, it is rather easy to write +	one should such a need arise.  You simply make a IPI call. + +  case 2) - each CPU has a separate timer interrupt + +	In this case, you need to set up IRQ such that each of them will +	call local_timer_interrupt().  In addition, you need to arrange +	one and only one of them to call timer_interrupt(). + +	You can also do the low-level version of those interrupt routines, +	following similar dispatching routes described above. + +Note about do_gettimeoffset(): + +  It is very likely the CPU counter registers are not sync'ed up in a SMP box. +  Therefore you cannot really use the many of the existing routines that +  are based on CPU counter.  You should wirte your own gettimeoffset rouinte +  if you want intra-jiffy resolution. |