[PATCH v3 04/23] Documentation: PCI: Guide to use pci endpoint configfs

Kishon Vijay Abraham I
2017-03-09T08:04:35Z

Add Documentation to help users use pci endpoint to configure
pci endpoint function and to bind the endpoint function
with endpoint controller.

Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
---
Documentation/PCI/00-INDEX | 2 +
Documentation/PCI/endpoint/pci-endpoint-cfs.txt | 105 +++++++++++++++++++++++
2 files changed, 107 insertions(+)
create mode 100644 Documentation/PCI/endpoint/pci-endpoint-cfs.txt

diff --git a/Documentation/PCI/00-INDEX b/Documentation/PCI/00-INDEX
index ba950b2..f84a23c 100644
--- a/Documentation/PCI/00-INDEX
+++ b/Documentation/PCI/00-INDEX
@@ -14,3 +14,5 @@ pcieaer-howto.txt
- the PCI Express Advanced Error Reporting Driver Guide HOWTO
endpoint/pci-endpoint.txt
- guide to add endpoint controller driver and endpoint function driver.
+endpoint/pci-endpoint-cfs.txt
+ - guide to use configfs to configure the pci endpoint function.
diff --git a/Documentation/PCI/endpoint/pci-endpoint-cfs.txt b/Documentation/PCI/endpoint/pci-endpoint-cfs.txt
new file mode 100644
index 0000000..8b2a828
--- /dev/null
+++ b/Documentation/PCI/endpoint/pci-endpoint-cfs.txt
@@ -0,0 +1,105 @@
+ CONFIGURING PCI ENDPOINT USING CONFIGFS
+ Kishon Vijay Abraham I <kishon@ti.com>
+
+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. (For introducing other mechanisms to
+configure the PCI Endpoint Function refer [1]).
+
+*) Mounting configfs
+
+The PCI Endpoint Core layer creates pci_ep directory in the mounted configfs
+directory. configfs can be mounted using the following command.
+
+ mount -t configfs none /sys/kernel/config
+
+*) Directory Structure
+
+The pci_ep configfs has two directories at its root: controllers and
+functions. Every EPC device present in the system will have an entry in
+the *controllers* directory and and every EPF driver present in the system
+will have an entry in the *functions* directory.
+
+/sys/kernel/config/pci_ep/
+ .. controllers/
+ .. functions/
+
+*) Creating EPF Device
+
+Every registered EPF driver will be listed in controllers directory. The
+entries corresponding to EPF driver will be created by the EPF core.
+
+/sys/kernel/config/pci_ep/functions/
+ .. <EPF Driver1>/
+ ... <EPF Device 11>/
+ ... <EPF Device 21>/
+ .. <EPF Driver2>/
+ ... <EPF Device 12>/
+ ... <EPF Device 22>/
+
+In order to create a <EPF device> of the type probed by <EPF Driver>, the
+user has to create a directory inside <EPF DriverN>.
+
+Every <EPF device> directory consists of the following entries that can be
+used to configure the standard configuration header of the endpoint function.
+(These entries are created by the framework when any new <EPF Device> is
+created)
+
+ .. <EPF Driver1>/
+ ... <EPF Device 11>/
+ ... vendorid
+ ... deviceid
+ ... revid
+ ... progif_code
+ ... subclass_code
+ ... baseclass_code
+ ... cache_line_size
+ ... subsys_vendor_id
+ ... subsys_id
+ ... interrupt_pin
+
+*) EPC Device
+
+Every registered EPC device will be listed in controllers directory. The
+entries corresponding to EPC device will be created by the EPC core.
+
+/sys/kernel/config/pci_ep/controllers/
+ .. <EPC Device1>/
+ ... <Symlink EPF Device11>/
+ ... <Symlink EPF Device12>/
+ ... start
+ .. <EPC Device2>/
+ ... <Symlink EPF Device21>/
+ ... <Symlink EPF Device22>/
+ ... start
+
+The <EPC Device> directory will have a list of symbolic links to
+<EPF Device>. These symbolic links should be created by the user to
+represent the functions present in the endpoint device.
+
+The <EPC Device> directory will also have a *start* field. Once
+"1" is written to this field, the endpoint device will be ready to
+establish the link with the host. This is usually done after
+all the EPF devices are created and linked with the EPC device.
+
+
+ | controllers/
+ | <Directory: EPC name>/
+ | <Symbolic Link: Function>
+ | start
+ | functions/
+ | <Directory: EPF driver>/
+ | <Directory: EPF device>/
+ | vendorid
+ | deviceid
+ | revid
+ | progif_code
+ | subclass_code
+ | baseclass_code
+ | cache_line_size
+ | subsys_vendor_id
+ | subsys_id
+ | interrupt_pin
+ | function
+
+[1] -> Documentation/PCI/endpoint/pci-endpoint.txt
--
1.7.9.5