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author | Linus Torvalds <torvalds@linux-foundation.org> | 2017-05-09 05:03:25 +0300 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-05-09 05:03:25 +0300 |
commit | 857f8640147c9fb43f20e43cbca6452710e1ca5d (patch) | |
tree | 76a92068d703b8001ca790ffa096d435fa24ae81 /Documentation/PCI/endpoint/pci-endpoint.txt | |
parent | 8f3207c7eab9d885cc64c778416537034a7d9c5b (diff) | |
parent | 3146c8f4de9b0858794a902f273aec13f168596e (diff) | |
download | linux-857f8640147c9fb43f20e43cbca6452710e1ca5d.tar.xz |
Merge tag 'pci-v4.12-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci
Pull PCI updates from Bjorn Helgaas:
- add framework for supporting PCIe devices in Endpoint mode (Kishon
Vijay Abraham I)
- use non-postable PCI config space mappings when possible (Lorenzo
Pieralisi)
- clean up and unify mmap of PCI BARs (David Woodhouse)
- export and unify Function Level Reset support (Christoph Hellwig)
- avoid FLR for Intel 82579 NICs (Sasha Neftin)
- add pci_request_irq() and pci_free_irq() helpers (Christoph Hellwig)
- short-circuit config access failures for disconnected devices (Keith
Busch)
- remove D3 sleep delay when possible (Adrian Hunter)
- freeze PME scan before suspending devices (Lukas Wunner)
- stop disabling MSI/MSI-X in pci_device_shutdown() (Prarit Bhargava)
- disable boot interrupt quirk for ASUS M2N-LR (Stefan Assmann)
- add arch-specific alignment control to improve device passthrough by
avoiding multiple BARs in a page (Yongji Xie)
- add sysfs sriov_drivers_autoprobe to control VF driver binding
(Bodong Wang)
- allow slots below PCI-to-PCIe "reverse bridges" (Bjorn Helgaas)
- fix crashes when unbinding host controllers that don't support
removal (Brian Norris)
- add driver for MicroSemi Switchtec management interface (Logan
Gunthorpe)
- add driver for Faraday Technology FTPCI100 host bridge (Linus
Walleij)
- add i.MX7D support (Andrey Smirnov)
- use generic MSI support for Aardvark (Thomas Petazzoni)
- make Rockchip driver modular (Brian Norris)
- advertise 128-byte Read Completion Boundary support for Rockchip
(Shawn Lin)
- advertise PCI_EXP_LNKSTA_SLC for Rockchip root port (Shawn Lin)
- convert atomic_t to refcount_t in HV driver (Elena Reshetova)
- add CPU IRQ affinity in HV driver (K. Y. Srinivasan)
- fix PCI bus removal in HV driver (Long Li)
- add support for ThunderX2 DMA alias topology (Jayachandran C)
- add ThunderX pass2.x 2nd node MCFG quirk (Tomasz Nowicki)
- add ITE 8893 bridge DMA alias quirk (Jarod Wilson)
- restrict Cavium ACS quirk only to CN81xx/CN83xx/CN88xx devices
(Manish Jaggi)
* tag 'pci-v4.12-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci: (146 commits)
PCI: Don't allow unbinding host controllers that aren't prepared
ARM: DRA7: clockdomain: Change the CLKTRCTRL of CM_PCIE_CLKSTCTRL to SW_WKUP
MAINTAINERS: Add PCI Endpoint maintainer
Documentation: PCI: Add userguide for PCI endpoint test function
tools: PCI: Add sample test script to invoke pcitest
tools: PCI: Add a userspace tool to test PCI endpoint
Documentation: misc-devices: Add Documentation for pci-endpoint-test driver
misc: Add host side PCI driver for PCI test function device
PCI: Add device IDs for DRA74x and DRA72x
dt-bindings: PCI: dra7xx: Add DT bindings to enable unaligned access
PCI: dwc: dra7xx: Workaround for errata id i870
dt-bindings: PCI: dra7xx: Add DT bindings for PCI dra7xx EP mode
PCI: dwc: dra7xx: Add EP mode support
PCI: dwc: dra7xx: Facilitate wrapper and MSI interrupts to be enabled independently
dt-bindings: PCI: Add DT bindings for PCI designware EP mode
PCI: dwc: designware: Add EP mode support
Documentation: PCI: Add binding documentation for pci-test endpoint function
ixgbe: Use pcie_flr() instead of duplicating it
IB/hfi1: Use pcie_flr() instead of duplicating it
PCI: imx6: Fix spelling mistake: "contol" -> "control"
...
Diffstat (limited to 'Documentation/PCI/endpoint/pci-endpoint.txt')
-rw-r--r-- | Documentation/PCI/endpoint/pci-endpoint.txt | 215 |
1 files changed, 215 insertions, 0 deletions
diff --git a/Documentation/PCI/endpoint/pci-endpoint.txt b/Documentation/PCI/endpoint/pci-endpoint.txt new file mode 100644 index 000000000000..9b1d66829290 --- /dev/null +++ b/Documentation/PCI/endpoint/pci-endpoint.txt @@ -0,0 +1,215 @@ + PCI ENDPOINT FRAMEWORK + Kishon Vijay Abraham I <kishon@ti.com> + +This document is a guide to use the PCI Endpoint Framework in order to create +endpoint controller driver, endpoint function driver, and using configfs +interface to bind the function driver to the controller driver. + +1. Introduction + +Linux has a comprehensive PCI subsystem to support PCI controllers that +operates in Root Complex mode. The subsystem has capability to scan PCI bus, +assign memory resources and IRQ resources, load PCI driver (based on +vendor ID, device ID), support other services like hot-plug, power management, +advanced error reporting and virtual channels. + +However the PCI controller IP integrated in some SoCs is capable of operating +either in Root Complex mode or Endpoint mode. PCI Endpoint Framework will +add endpoint mode support in Linux. This will help to run Linux in an +EP system which can have a wide variety of use cases from testing or +validation, co-processor accelerator, etc. + +2. PCI Endpoint Core + +The PCI Endpoint Core layer comprises 3 components: the Endpoint Controller +library, the Endpoint Function library, and the configfs layer to bind the +endpoint function with the endpoint controller. + +2.1 PCI Endpoint Controller(EPC) Library + +The EPC library provides APIs to be used by the controller that can operate +in endpoint mode. It also provides APIs to be used by function driver/library +in order to implement a particular endpoint function. + +2.1.1 APIs for the PCI controller Driver + +This section lists the APIs that the PCI Endpoint core provides to be used +by the PCI controller driver. + +*) devm_pci_epc_create()/pci_epc_create() + + The PCI controller driver should implement the following ops: + * write_header: ops to populate configuration space header + * set_bar: ops to configure the BAR + * clear_bar: ops to reset the BAR + * alloc_addr_space: ops to allocate in PCI controller address space + * free_addr_space: ops to free the allocated address space + * raise_irq: ops to raise a legacy or MSI interrupt + * start: ops to start the PCI link + * stop: ops to stop the PCI link + + The PCI controller driver can then create a new EPC device by invoking + devm_pci_epc_create()/pci_epc_create(). + +*) devm_pci_epc_destroy()/pci_epc_destroy() + + The PCI controller driver can destroy the EPC device created by either + devm_pci_epc_create() or pci_epc_create() using devm_pci_epc_destroy() or + pci_epc_destroy(). + +*) pci_epc_linkup() + + In order to notify all the function devices that the EPC device to which + they are linked has established a link with the host, the PCI controller + driver should invoke pci_epc_linkup(). + +*) pci_epc_mem_init() + + Initialize the pci_epc_mem structure used for allocating EPC addr space. + +*) pci_epc_mem_exit() + + Cleanup the pci_epc_mem structure allocated during pci_epc_mem_init(). + +2.1.2 APIs for the PCI Endpoint Function Driver + +This section lists the APIs that the PCI Endpoint core provides to be used +by the PCI endpoint function driver. + +*) pci_epc_write_header() + + The PCI endpoint function driver should use pci_epc_write_header() to + write the standard configuration header to the endpoint controller. + +*) pci_epc_set_bar() + + The PCI endpoint function driver should use pci_epc_set_bar() to configure + the Base Address Register in order for the host to assign PCI addr space. + Register space of the function driver is usually configured + using this API. + +*) pci_epc_clear_bar() + + The PCI endpoint function driver should use pci_epc_clear_bar() to reset + the BAR. + +*) pci_epc_raise_irq() + + The PCI endpoint function driver should use pci_epc_raise_irq() to raise + Legacy Interrupt or MSI Interrupt. + +*) pci_epc_mem_alloc_addr() + + The PCI endpoint function driver should use pci_epc_mem_alloc_addr(), to + allocate memory address from EPC addr space which is required to access + RC's buffer + +*) pci_epc_mem_free_addr() + + The PCI endpoint function driver should use pci_epc_mem_free_addr() to + free the memory space allocated using pci_epc_mem_alloc_addr(). + +2.1.3 Other APIs + +There are other APIs provided by the EPC library. These are used for binding +the EPF device with EPC device. pci-ep-cfs.c can be used as reference for +using these APIs. + +*) pci_epc_get() + + Get a reference to the PCI endpoint controller based on the device name of + the controller. + +*) pci_epc_put() + + Release the reference to the PCI endpoint controller obtained using + pci_epc_get() + +*) pci_epc_add_epf() + + Add a PCI endpoint function to a PCI endpoint controller. A PCIe device + can have up to 8 functions according to the specification. + +*) pci_epc_remove_epf() + + Remove the PCI endpoint function from PCI endpoint controller. + +*) pci_epc_start() + + The PCI endpoint function driver should invoke pci_epc_start() once it + has configured the endpoint function and wants to start the PCI link. + +*) pci_epc_stop() + + The PCI endpoint function driver should invoke pci_epc_stop() to stop + the PCI LINK. + +2.2 PCI Endpoint Function(EPF) Library + +The EPF library provides APIs to be used by the function driver and the EPC +library to provide endpoint mode functionality. + +2.2.1 APIs for the PCI Endpoint Function Driver + +This section lists the APIs that the PCI Endpoint core provides to be used +by the PCI endpoint function driver. + +*) pci_epf_register_driver() + + The PCI Endpoint Function driver should implement the following ops: + * bind: ops to perform when a EPC device has been bound to EPF device + * unbind: ops to perform when a binding has been lost between a EPC + device and EPF device + * linkup: ops to perform when the EPC device has established a + connection with a host system + + The PCI Function driver can then register the PCI EPF driver by using + pci_epf_register_driver(). + +*) pci_epf_unregister_driver() + + The PCI Function driver can unregister the PCI EPF driver by using + pci_epf_unregister_driver(). + +*) pci_epf_alloc_space() + + The PCI Function driver can allocate space for a particular BAR using + pci_epf_alloc_space(). + +*) pci_epf_free_space() + + The PCI Function driver can free the allocated space + (using pci_epf_alloc_space) by invoking pci_epf_free_space(). + +2.2.2 APIs for the PCI Endpoint Controller Library +This section lists the APIs that the PCI Endpoint core provides to be used +by the PCI endpoint controller library. + +*) pci_epf_linkup() + + The PCI endpoint controller library invokes pci_epf_linkup() when the + EPC device has established the connection to the host. + +2.2.2 Other APIs +There are other APIs provided by the EPF library. These are used to notify +the function driver when the EPF device is bound to the EPC device. +pci-ep-cfs.c can be used as reference for using these APIs. + +*) pci_epf_create() + + Create a new PCI EPF device by passing the name of the PCI EPF device. + This name will be used to bind the the EPF device to a EPF driver. + +*) pci_epf_destroy() + + Destroy the created PCI EPF device. + +*) pci_epf_bind() + + pci_epf_bind() should be invoked when the EPF device has been bound to + a EPC device. + +*) pci_epf_unbind() + + pci_epf_unbind() should be invoked when the binding between EPC device + and EPF device is lost. |