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author | Bjorn Helgaas <bhelgaas@google.com> | 2021-02-24 14:59:23 -0600 |
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committer | Bjorn Helgaas <bhelgaas@google.com> | 2021-02-24 14:59:23 -0600 |
commit | 2ef38d7e2b01d5668c1e607ef49d866b40403806 (patch) | |
tree | b7afc3b15e81f5a2e48b835a64dc7aa4f4e902ea /Documentation | |
parent | 52c1de640eae2768e66f35dc74f28184c1652928 (diff) | |
parent | b28a23676e0945934df983fcc8df0bfd9b24f866 (diff) | |
download | linux-2ef38d7e2b01d5668c1e607ef49d866b40403806.tar.bz2 |
Merge branch 'pci/ntb'
- Account for 64-bit BARs in pci_epc_get_first_free_bar() (Kishon Vijay
Abraham I)
- Add pci_epc_get_next_free_bar() helper (Kishon Vijay Abraham I)
- Return error codes on failure of endpoint BAR interfaces (Kishon Vijay
Abraham I)
- Remove unused pci_epf_match_device() (Kishon Vijay Abraham I)
- Add support for secondary endpoint controller to prepare for NTB endpoint
functionality (Kishon Vijay Abraham I)
- Add configfs support for secondary endpoint controller (Kishon Vijay
Abraham I)
- Add MSI address mapping ops for NTB doorbell support (Kishon Vijay
Abraham I)
- Add ops for endpoint function-specific attributes (Kishon Vijay Abraham
I)
- Allow configfs subdirectory for endpoint function configuration (Kishon
Vijay Abraham I)
- Implement cadence MSI address mapping ops (Kishon Vijay Abraham I)
- Configure cadence LM_EP_FUNC_CFG based on epc->function_num_map (Kishon
Vijay Abraham I)
- Add endpoint-side driver to provide NTB functionality (Kishon Vijay
Abraham I)
- Add host-side driver for generic EPF NTB functionality (Kishon Vijay
Abraham I)
- Document NTB endpoint functionality (Kishon Vijay Abraham I)
* pci/ntb:
Documentation: PCI: Add PCI endpoint NTB function user guide
Documentation: PCI: Add configfs binding documentation for pci-ntb endpoint function
NTB: Add support for EPF PCI Non-Transparent Bridge
PCI: Add TI J721E device to PCI IDs
PCI: endpoint: Add EP function driver to provide NTB functionality
PCI: cadence: Configure LM_EP_FUNC_CFG based on epc->function_num_map
PCI: cadence: Implement ->msi_map_irq() ops
PCI: endpoint: Allow user to create sub-directory of 'EPF Device' directory
PCI: endpoint: Add pci_epf_ops to expose function-specific attrs
PCI: endpoint: Add pci_epc_ops to map MSI IRQ
PCI: endpoint: Add support in configfs to associate two EPCs with EPF
PCI: endpoint: Add support to associate secondary EPC with EPF
PCI: endpoint: Remove unused pci_epf_match_device()
PCI: endpoint: Make *_free_bar() to return error codes on failure
PCI: endpoint: Add helper API to get the 'next' unreserved BAR
PCI: endpoint: Make *_get_first_free_bar() take into account 64 bit BAR
Documentation: PCI: Add specification for the PCI NTB function device
Diffstat (limited to 'Documentation')
-rw-r--r-- | Documentation/PCI/endpoint/function/binding/pci-ntb.rst | 38 | ||||
-rw-r--r-- | Documentation/PCI/endpoint/index.rst | 3 | ||||
-rw-r--r-- | Documentation/PCI/endpoint/pci-endpoint-cfs.rst | 10 | ||||
-rw-r--r-- | Documentation/PCI/endpoint/pci-ntb-function.rst | 348 | ||||
-rw-r--r-- | Documentation/PCI/endpoint/pci-ntb-howto.rst | 161 |
5 files changed, 560 insertions, 0 deletions
diff --git a/Documentation/PCI/endpoint/function/binding/pci-ntb.rst b/Documentation/PCI/endpoint/function/binding/pci-ntb.rst new file mode 100644 index 000000000000..40253d3d5163 --- /dev/null +++ b/Documentation/PCI/endpoint/function/binding/pci-ntb.rst @@ -0,0 +1,38 @@ +.. SPDX-License-Identifier: GPL-2.0 + +========================== +PCI NTB Endpoint Function +========================== + +1) Create a subdirectory to pci_epf_ntb directory in configfs. + +Standard EPF Configurable Fields: + +================ =========================================================== +vendorid should be 0x104c +deviceid should be 0xb00d for TI's J721E SoC +revid don't care +progif_code don't care +subclass_code should be 0x00 +baseclass_code should be 0x5 +cache_line_size don't care +subsys_vendor_id don't care +subsys_id don't care +interrupt_pin don't care +msi_interrupts don't care +msix_interrupts don't care +================ =========================================================== + +2) Create a subdirectory to directory created in 1 + +NTB EPF specific configurable fields: + +================ =========================================================== +db_count Number of doorbells; default = 4 +mw1 size of memory window1 +mw2 size of memory window2 +mw3 size of memory window3 +mw4 size of memory window4 +num_mws Number of memory windows; max = 4 +spad_count Number of scratchpad registers; default = 64 +================ =========================================================== diff --git a/Documentation/PCI/endpoint/index.rst b/Documentation/PCI/endpoint/index.rst index 4ca7439fbfc9..38ea1f604b6d 100644 --- a/Documentation/PCI/endpoint/index.rst +++ b/Documentation/PCI/endpoint/index.rst @@ -11,5 +11,8 @@ PCI Endpoint Framework pci-endpoint-cfs pci-test-function pci-test-howto + pci-ntb-function + pci-ntb-howto function/binding/pci-test + function/binding/pci-ntb diff --git a/Documentation/PCI/endpoint/pci-endpoint-cfs.rst b/Documentation/PCI/endpoint/pci-endpoint-cfs.rst index 1bbd81ed06c8..696f8eeb4738 100644 --- a/Documentation/PCI/endpoint/pci-endpoint-cfs.rst +++ b/Documentation/PCI/endpoint/pci-endpoint-cfs.rst @@ -68,6 +68,16 @@ created) ... subsys_vendor_id ... subsys_id ... interrupt_pin + ... primary/ + ... <Symlink EPC Device1>/ + ... secondary/ + ... <Symlink EPC Device2>/ + +If an EPF device has to be associated with 2 EPCs (like in the case of +Non-transparent bridge), symlink of endpoint controller connected to primary +interface should be added in 'primary' directory and symlink of endpoint +controller connected to secondary interface should be added in 'secondary' +directory. EPC Device ========== diff --git a/Documentation/PCI/endpoint/pci-ntb-function.rst b/Documentation/PCI/endpoint/pci-ntb-function.rst new file mode 100644 index 000000000000..3b9d836a4924 --- /dev/null +++ b/Documentation/PCI/endpoint/pci-ntb-function.rst @@ -0,0 +1,348 @@ +.. SPDX-License-Identifier: GPL-2.0 + +================= +PCI NTB Function +================= + +:Author: Kishon Vijay Abraham I <kishon@ti.com> + +PCI Non-Transparent Bridges (NTB) allow two host systems to communicate +with each other by exposing each host as a device to the other host. +NTBs typically support the ability to generate interrupts on the remote +machine, expose memory ranges as BARs, and perform DMA. They also support +scratchpads, which are areas of memory within the NTB that are accessible +from both machines. + +PCI NTB Function allows two different systems (or hosts) to communicate +with each other by configuring the endpoint instances in such a way that +transactions from one system are routed to the other system. + +In the below diagram, PCI NTB function configures the SoC with multiple +PCI Endpoint (EP) instances in such a way that transactions from one EP +controller are routed to the other EP controller. Once PCI NTB function +configures the SoC with multiple EP instances, HOST1 and HOST2 can +communicate with each other using SoC as a bridge. + +.. code-block:: text + + +-------------+ +-------------+ + | | | | + | HOST1 | | HOST2 | + | | | | + +------^------+ +------^------+ + | | + | | + +---------|-------------------------------------------------|---------+ + | +------v------+ +------v------+ | + | | | | | | + | | EP | | EP | | + | | CONTROLLER1 | | CONTROLLER2 | | + | | <-----------------------------------> | | + | | | | | | + | | | | | | + | | | SoC With Multiple EP Instances | | | + | | | (Configured using NTB Function) | | | + | +-------------+ +-------------+ | + +---------------------------------------------------------------------+ + +Constructs used for Implementing NTB +==================================== + + 1) Config Region + 2) Self Scratchpad Registers + 3) Peer Scratchpad Registers + 4) Doorbell (DB) Registers + 5) Memory Window (MW) + + +Config Region: +-------------- + +Config Region is a construct that is specific to NTB implemented using NTB +Endpoint Function Driver. The host and endpoint side NTB function driver will +exchange information with each other using this region. Config Region has +Control/Status Registers for configuring the Endpoint Controller. Host can +write into this region for configuring the outbound Address Translation Unit +(ATU) and to indicate the link status. Endpoint can indicate the status of +commands issued by host in this region. Endpoint can also indicate the +scratchpad offset and number of memory windows to the host using this region. + +The format of Config Region is given below. All the fields here are 32 bits. + +.. code-block:: text + + +------------------------+ + | COMMAND | + +------------------------+ + | ARGUMENT | + +------------------------+ + | STATUS | + +------------------------+ + | TOPOLOGY | + +------------------------+ + | ADDRESS (LOWER 32) | + +------------------------+ + | ADDRESS (UPPER 32) | + +------------------------+ + | SIZE | + +------------------------+ + | NO OF MEMORY WINDOW | + +------------------------+ + | MEMORY WINDOW1 OFFSET | + +------------------------+ + | SPAD OFFSET | + +------------------------+ + | SPAD COUNT | + +------------------------+ + | DB ENTRY SIZE | + +------------------------+ + | DB DATA | + +------------------------+ + | : | + +------------------------+ + | : | + +------------------------+ + | DB DATA | + +------------------------+ + + + COMMAND: + + NTB function supports three commands: + + CMD_CONFIGURE_DOORBELL (0x1): Command to configure doorbell. Before + invoking this command, the host should allocate and initialize + MSI/MSI-X vectors (i.e., initialize the MSI/MSI-X Capability in the + Endpoint). The endpoint on receiving this command will configure + the outbound ATU such that transactions to Doorbell BAR will be routed + to the MSI/MSI-X address programmed by the host. The ARGUMENT + register should be populated with number of DBs to configure (in the + lower 16 bits) and if MSI or MSI-X should be configured (BIT 16). + + CMD_CONFIGURE_MW (0x2): Command to configure memory window (MW). The + host invokes this command after allocating a buffer that can be + accessed by remote host. The allocated address should be programmed + in the ADDRESS register (64 bit), the size should be programmed in + the SIZE register and the memory window index should be programmed + in the ARGUMENT register. The endpoint on receiving this command + will configure the outbound ATU such that transactions to MW BAR + are routed to the address provided by the host. + + CMD_LINK_UP (0x3): Command to indicate an NTB application is + bound to the EP device on the host side. Once the endpoint + receives this command from both the hosts, the endpoint will + raise a LINK_UP event to both the hosts to indicate the host + NTB applications can start communicating with each other. + + ARGUMENT: + + The value of this register is based on the commands issued in + command register. See COMMAND section for more information. + + TOPOLOGY: + + Set to NTB_TOPO_B2B_USD for Primary interface + Set to NTB_TOPO_B2B_DSD for Secondary interface + + ADDRESS/SIZE: + + Address and Size to be used while configuring the memory window. + See "CMD_CONFIGURE_MW" for more info. + + MEMORY WINDOW1 OFFSET: + + Memory Window 1 and Doorbell registers are packed together in the + same BAR. The initial portion of the region will have doorbell + registers and the latter portion of the region is for memory window 1. + This register will specify the offset of the memory window 1. + + NO OF MEMORY WINDOW: + + Specifies the number of memory windows supported by the NTB device. + + SPAD OFFSET: + + Self scratchpad region and config region are packed together in the + same BAR. The initial portion of the region will have config region + and the latter portion of the region is for self scratchpad. This + register will specify the offset of the self scratchpad registers. + + SPAD COUNT: + + Specifies the number of scratchpad registers supported by the NTB + device. + + DB ENTRY SIZE: + + Used to determine the offset within the DB BAR that should be written + in order to raise doorbell. EPF NTB can use either MSI or MSI-X to + ring doorbell (MSI-X support will be added later). MSI uses same + address for all the interrupts and MSI-X can provide different + addresses for different interrupts. The MSI/MSI-X address is provided + by the host and the address it gives is based on the MSI/MSI-X + implementation supported by the host. For instance, ARM platform + using GIC ITS will have the same MSI-X address for all the interrupts. + In order to support all the combinations and use the same mechanism + for both MSI and MSI-X, EPF NTB allocates a separate region in the + Outbound Address Space for each of the interrupts. This region will + be mapped to the MSI/MSI-X address provided by the host. If a host + provides the same address for all the interrupts, all the regions + will be translated to the same address. If a host provides different + addresses, the regions will be translated to different addresses. This + will ensure there is no difference while raising the doorbell. + + DB DATA: + + EPF NTB supports 32 interrupts, so there are 32 DB DATA registers. + This holds the MSI/MSI-X data that has to be written to MSI address + for raising doorbell interrupt. This will be populated by EPF NTB + while invoking CMD_CONFIGURE_DOORBELL. + +Scratchpad Registers: +--------------------- + + Each host has its own register space allocated in the memory of NTB endpoint + controller. They are both readable and writable from both sides of the bridge. + They are used by applications built over NTB and can be used to pass control + and status information between both sides of a device. + + Scratchpad registers has 2 parts + 1) Self Scratchpad: Host's own register space + 2) Peer Scratchpad: Remote host's register space. + +Doorbell Registers: +------------------- + + Doorbell Registers are used by the hosts to interrupt each other. + +Memory Window: +-------------- + + Actual transfer of data between the two hosts will happen using the + memory window. + +Modeling Constructs: +==================== + +There are 5 or more distinct regions (config, self scratchpad, peer +scratchpad, doorbell, one or more memory windows) to be modeled to achieve +NTB functionality. At least one memory window is required while more than +one is permitted. All these regions should be mapped to BARs for hosts to +access these regions. + +If one 32-bit BAR is allocated for each of these regions, the scheme would +look like this: + +====== =============== +BAR NO CONSTRUCTS USED +====== =============== +BAR0 Config Region +BAR1 Self Scratchpad +BAR2 Peer Scratchpad +BAR3 Doorbell +BAR4 Memory Window 1 +BAR5 Memory Window 2 +====== =============== + +However if we allocate a separate BAR for each of the regions, there would not +be enough BARs for all the regions in a platform that supports only 64-bit +BARs. + +In order to be supported by most of the platforms, the regions should be +packed and mapped to BARs in a way that provides NTB functionality and +also makes sure the host doesn't access any region that it is not supposed +to. + +The following scheme is used in EPF NTB Function: + +====== =============================== +BAR NO CONSTRUCTS USED +====== =============================== +BAR0 Config Region + Self Scratchpad +BAR1 Peer Scratchpad +BAR2 Doorbell + Memory Window 1 +BAR3 Memory Window 2 +BAR4 Memory Window 3 +BAR5 Memory Window 4 +====== =============================== + +With this scheme, for the basic NTB functionality 3 BARs should be sufficient. + +Modeling Config/Scratchpad Region: +---------------------------------- + +.. code-block:: text + + +-----------------+------->+------------------+ +-----------------+ + | BAR0 | | CONFIG REGION | | BAR0 | + +-----------------+----+ +------------------+<-------+-----------------+ + | BAR1 | | |SCRATCHPAD REGION | | BAR1 | + +-----------------+ +-->+------------------+<-------+-----------------+ + | BAR2 | Local Memory | BAR2 | + +-----------------+ +-----------------+ + | BAR3 | | BAR3 | + +-----------------+ +-----------------+ + | BAR4 | | BAR4 | + +-----------------+ +-----------------+ + | BAR5 | | BAR5 | + +-----------------+ +-----------------+ + EP CONTROLLER 1 EP CONTROLLER 2 + +Above diagram shows Config region + Scratchpad region for HOST1 (connected to +EP controller 1) allocated in local memory. The HOST1 can access the config +region and scratchpad region (self scratchpad) using BAR0 of EP controller 1. +The peer host (HOST2 connected to EP controller 2) can also access this +scratchpad region (peer scratchpad) using BAR1 of EP controller 2. This +diagram shows the case where Config region and Scratchpad regions are allocated +for HOST1, however the same is applicable for HOST2. + +Modeling Doorbell/Memory Window 1: +---------------------------------- + +.. code-block:: text + + +-----------------+ +----->+----------------+-----------+-----------------+ + | BAR0 | | | Doorbell 1 +-----------> MSI-X ADDRESS 1 | + +-----------------+ | +----------------+ +-----------------+ + | BAR1 | | | Doorbell 2 +---------+ | | + +-----------------+----+ +----------------+ | | | + | BAR2 | | Doorbell 3 +-------+ | +-----------------+ + +-----------------+----+ +----------------+ | +-> MSI-X ADDRESS 2 | + | BAR3 | | | Doorbell 4 +-----+ | +-----------------+ + +-----------------+ | |----------------+ | | | | + | BAR4 | | | | | | +-----------------+ + +-----------------+ | | MW1 +---+ | +-->+ MSI-X ADDRESS 3|| + | BAR5 | | | | | | +-----------------+ + +-----------------+ +----->-----------------+ | | | | + EP CONTROLLER 1 | | | | +-----------------+ + | | | +---->+ MSI-X ADDRESS 4 | + +----------------+ | +-----------------+ + EP CONTROLLER 2 | | | + (OB SPACE) | | | + +-------> MW1 | + | | + | | + +-----------------+ + | | + | | + | | + | | + | | + +-----------------+ + PCI Address Space + (Managed by HOST2) + +Above diagram shows how the doorbell and memory window 1 is mapped so that +HOST1 can raise doorbell interrupt on HOST2 and also how HOST1 can access +buffers exposed by HOST2 using memory window1 (MW1). Here doorbell and +memory window 1 regions are allocated in EP controller 2 outbound (OB) address +space. Allocating and configuring BARs for doorbell and memory window1 +is done during the initialization phase of NTB endpoint function driver. +Mapping from EP controller 2 OB space to PCI address space is done when HOST2 +sends CMD_CONFIGURE_MW/CMD_CONFIGURE_DOORBELL. + +Modeling Optional Memory Windows: +--------------------------------- + +This is modeled the same was as MW1 but each of the additional memory windows +is mapped to separate BARs. diff --git a/Documentation/PCI/endpoint/pci-ntb-howto.rst b/Documentation/PCI/endpoint/pci-ntb-howto.rst new file mode 100644 index 000000000000..1884bf29caba --- /dev/null +++ b/Documentation/PCI/endpoint/pci-ntb-howto.rst @@ -0,0 +1,161 @@ +.. SPDX-License-Identifier: GPL-2.0 + +=================================================================== +PCI Non-Transparent Bridge (NTB) Endpoint Function (EPF) User Guide +=================================================================== + +:Author: Kishon Vijay Abraham I <kishon@ti.com> + +This document is a guide to help users use pci-epf-ntb function driver +and ntb_hw_epf host driver for NTB functionality. The list of steps to +be followed in the host side and EP side is given below. For the hardware +configuration and internals of NTB using configurable endpoints see +Documentation/PCI/endpoint/pci-ntb-function.rst + +Endpoint Device +=============== + +Endpoint Controller Devices +--------------------------- + +For implementing NTB functionality at least two endpoint controller devices +are required. + +To find the list of endpoint controller devices in the system:: + + # ls /sys/class/pci_epc/ + 2900000.pcie-ep 2910000.pcie-ep + +If PCI_ENDPOINT_CONFIGFS is enabled:: + + # ls /sys/kernel/config/pci_ep/controllers + 2900000.pcie-ep 2910000.pcie-ep + + +Endpoint Function Drivers +------------------------- + +To find the list of endpoint function drivers in the system:: + + # ls /sys/bus/pci-epf/drivers + pci_epf_ntb pci_epf_ntb + +If PCI_ENDPOINT_CONFIGFS is enabled:: + + # ls /sys/kernel/config/pci_ep/functions + pci_epf_ntb pci_epf_ntb + + +Creating pci-epf-ntb Device +---------------------------- + +PCI endpoint function device can be created using the configfs. To create +pci-epf-ntb device, the following commands can be used:: + + # mount -t configfs none /sys/kernel/config + # cd /sys/kernel/config/pci_ep/ + # mkdir functions/pci_epf_ntb/func1 + +The "mkdir func1" above creates the pci-epf-ntb function device that will +be probed by pci_epf_ntb driver. + +The PCI endpoint framework populates the directory with the following +configurable fields:: + + # ls functions/pci_epf_ntb/func1 + baseclass_code deviceid msi_interrupts pci-epf-ntb.0 + progif_code secondary subsys_id vendorid + cache_line_size interrupt_pin msix_interrupts primary + revid subclass_code subsys_vendor_id + +The PCI endpoint function driver populates these entries with default values +when the device is bound to the driver. The pci-epf-ntb driver populates +vendorid with 0xffff and interrupt_pin with 0x0001:: + + # cat functions/pci_epf_ntb/func1/vendorid + 0xffff + # cat functions/pci_epf_ntb/func1/interrupt_pin + 0x0001 + + +Configuring pci-epf-ntb Device +------------------------------- + +The user can configure the pci-epf-ntb device using its configfs entry. In order +to change the vendorid and the deviceid, the following +commands can be used:: + + # echo 0x104c > functions/pci_epf_ntb/func1/vendorid + # echo 0xb00d > functions/pci_epf_ntb/func1/deviceid + +In order to configure NTB specific attributes, a new sub-directory to func1 +should be created:: + + # mkdir functions/pci_epf_ntb/func1/pci_epf_ntb.0/ + +The NTB function driver will populate this directory with various attributes +that can be configured by the user:: + + # ls functions/pci_epf_ntb/func1/pci_epf_ntb.0/ + db_count mw1 mw2 mw3 mw4 num_mws + spad_count + +A sample configuration for NTB function is given below:: + + # echo 4 > functions/pci_epf_ntb/func1/pci_epf_ntb.0/db_count + # echo 128 > functions/pci_epf_ntb/func1/pci_epf_ntb.0/spad_count + # echo 2 > functions/pci_epf_ntb/func1/pci_epf_ntb.0/num_mws + # echo 0x100000 > functions/pci_epf_ntb/func1/pci_epf_ntb.0/mw1 + # echo 0x100000 > functions/pci_epf_ntb/func1/pci_epf_ntb.0/mw2 + +Binding pci-epf-ntb Device to EP Controller +-------------------------------------------- + +NTB function device should be attached to two PCI endpoint controllers +connected to the two hosts. Use the 'primary' and 'secondary' entries +inside NTB function device to attach one PCI endpoint controller to +primary interface and the other PCI endpoint controller to the secondary +interface:: + + # ln -s controllers/2900000.pcie-ep/ functions/pci-epf-ntb/func1/primary + # ln -s controllers/2910000.pcie-ep/ functions/pci-epf-ntb/func1/secondary + +Once the above step is completed, both the PCI endpoint controllers are ready to +establish a link with the host. + + +Start the Link +-------------- + +In order for the endpoint device to establish a link with the host, the _start_ +field should be populated with '1'. For NTB, both the PCI endpoint controllers +should establish link with the host:: + + # echo 1 > controllers/2900000.pcie-ep/start + # echo 1 > controllers/2910000.pcie-ep/start + + +RootComplex Device +================== + +lspci Output +------------ + +Note that the devices listed here correspond to the values populated in +"Creating pci-epf-ntb Device" section above:: + + # lspci + 0000:00:00.0 PCI bridge: Texas Instruments Device b00d + 0000:01:00.0 RAM memory: Texas Instruments Device b00d + + +Using ntb_hw_epf Device +----------------------- + +The host side software follows the standard NTB software architecture in Linux. +All the existing client side NTB utilities like NTB Transport Client and NTB +Netdev, NTB Ping Pong Test Client and NTB Tool Test Client can be used with NTB +function device. + +For more information on NTB see +:doc:`Non-Transparent Bridge <../../driver-api/ntb>` |