Add Documentation to let users enable endpoint mode in the PCI
controller and add new PCI endpoint function.
Signed-off-by: Kishon Vijay Abraham I <kis...@ti.com>
---
Documentation/PCI/00-INDEX | 2 +
Documentation/PCI/pci-endpoint.txt | 199 ++++++++++++++++++++++++++++++++++++
2 files changed, 201 insertions(+)
create mode 100644 Documentation/PCI/pci-endpoint.txt
diff --git a/Documentation/PCI/00-INDEX b/Documentation/PCI/00-INDEX
index 147231f..e422b8151 100644
--- a/Documentation/PCI/00-INDEX
+++ b/Documentation/PCI/00-INDEX
@@ -12,3 +12,5 @@ pci.txt
- info on the PCI subsystem for device driver authors
pcieaer-howto.txt
- the PCI Express Advanced Error Reporting Driver Guide HOWTO
+pci-endpoint.txt
+ - guide to add endpoint controller driver and endpoint function driver.
diff --git a/Documentation/PCI/pci-endpoint.txt
b/Documentation/PCI/pci-endpoint.txt
new file mode 100644
index 0000000..a453aaa
--- /dev/null
+++ b/Documentation/PCI/pci-endpoint.txt
@@ -0,0 +1,199 @@
+ PCI ENDPOINT FRAMEWORK
+ Kishon Vijay Abraham I <kis...@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
+vendorid, deviceid), support other services like hot-plug, power management,
+advanced error reporting and virtual channels.
+
+However PCI controller IPs integrated in certain SoC 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 of 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()
+
+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_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.
+
+2.1.3 APIs for the PCI Endpoint Function Library
+
+This section lists the APIs that the PCI Endpoint core provides to be used
+by the PCI endpoint function library.
+
+*) pci_epc_bind_epf()
+
+ The PCI endpoint function library uses pci_epc_bind_epf() to bind the
+ function driver with a controller driver. The binding will be based on
+ the endpoint controller function name (as seen in /sys/class/pci_epc/).
+
+*) pci_epc_unbind_epf()
+
+ The PCI endpoint function library uses pci_epc_unbind_epf() to unbind
+ the function driver from the controller driver. After unbind the controller
+ driver can be bound to any other function driver.
+
+2.2 PCI Endpoint Function(EPF) Library
+
+The EPF library provides APIs to be used by the function driver and the EPC
+library in order 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_bind()
+
+ The PCI endpoint controller library invokes pci_epf_bind() when the EPF
+ device has been bound to a EPC device.
+
+*) pci_epf_unbind()
+
+ The PCI endpoint controller library invokes pci_epf_unbind() when the
+ binding between EPC device and EPF device is lost.
+
+*) pci_epf_linkup()
+
+ The PCI endpoint controller library invokes pci_epf_linkup() when the
+ EPC device has established the connection to the host.
+
+2.3 CONFIGFS
+
+The PCI Endpoint Core exposes configfs entry (pci_ep) in order to configure the
+PCI Endpoint Function and in order to bind the endpoint function
+with the endpoint controller. Every folder in pci_ep/ represent a PCI
+endpoint function.
+
+The following entries can be used to configure the standard configuration
+header of the endpoint function.
+ vendorid
+ deviceid
+ revid
+ progif_code
+ subclass_code
+ baseclass_code
+ cache_line_size
+ subsys_vendor_id
+ subsys_id
+ interrupt_pin
+
+The following entries has special meaning:
+ function: this readonly entry shows the name using which the function
+ driver will be bound to this function
+ epc : the name of the EPC device this function should be bound to.
+ The name of the EPC device should be from /sys/class/pci_epc.
+
+3. Known Limitations
+
+The Endpoint Core doesn't support adding multi-function devices.
--
1.7.9.5
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