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authorLinus Torvalds <torvalds@linux-foundation.org>2017-05-09 05:03:25 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2017-05-09 05:03:25 +0300
commit857f8640147c9fb43f20e43cbca6452710e1ca5d (patch)
tree76a92068d703b8001ca790ffa096d435fa24ae81 /Documentation/PCI/endpoint/pci-endpoint.txt
parent8f3207c7eab9d885cc64c778416537034a7d9c5b (diff)
parent3146c8f4de9b0858794a902f273aec13f168596e (diff)
downloadlinux-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" ...
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+ 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.