[RFC PATCH] Documentation: PCI: guide to use PCI Endpoint Core Layer

[Kishon Vijay Abraham I]

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 
---
 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 000..a453aaa
--- /dev/null
+++ b/Documentation/PCI/pci-endpoint.txt
@@ -0,0 +1,199 @@
+   PCI ENDPOINT FRAMEWORK
+   Kishon Vijay Abraham I 
+
+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 

[RFC PATCH] Documentation: PCI: guide to use PCI Endpoint Core Layer

[Kishon Vijay Abraham I]

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 
---
 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 000..a453aaa
--- /dev/null
+++ b/Documentation/PCI/pci-endpoint.txt
@@ -0,0 +1,199 @@
+   PCI ENDPOINT FRAMEWORK
+   Kishon Vijay Abraham I 
+
+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