Thread (68 messages) 68 messages, 5 authors, 2017-02-16

[PATCH 17/37] Documentation: PCI: Guide to use pci endpoint configfs

From: Kishon Vijay Abraham I <hidden>
Date: 2017-01-12 10:30:50
Also in: linux-arm-kernel, linux-arm-msm, linux-devicetree, linux-omap, linux-pci, linux-samsung-soc, lkml
Subsystem: documentation, pci endpoint subsystem, pci subsystem, the rest · Maintainers: Jonathan Corbet, Manivannan Sadhasivam, Krzysztof Wilczyński, Bjorn Helgaas, Linus Torvalds

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 <redacted>
---
 Documentation/PCI/00-INDEX                      |    2 +
 Documentation/PCI/endpoint/pci-endpoint-cfs.txt |   84 +++++++++++++++++++++++
 2 files changed, 86 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..b1f1613
--- /dev/null
+++ b/Documentation/PCI/endpoint/pci-endpoint-cfs.txt
@@ -0,0 +1,84 @@
+                   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 directory structure has been created to reflect the
+natural tree like structure of PCI devices. So every directory created
+inside pci_ep represents a EPC device and every directory created inside
+epf directory represents EPF device.
+
+/sys/kernel/config/pci_ep/
+			 | <dir>/ --------------------------------------> [2]
+				| epc
+				| epf/
+				     | <dir>/ --------------------------> [3]
+					    | vendorid
+					    | deviceid
+					    | revid
+					    | progif_code
+					    | subclass_code
+					    | baseclass_code
+					    | cache_line_size
+					    | subsys_vendor_id
+					    | subsys_id
+					    | interrupt_pin
+					    | function
+
+*) Creating configfs entry for EPC
+
+Any directory created inside *pci_ep* represents an EPC device. In the above
+directory structure [2] represents an EPC device. It consists of
+
+	*) epc: Use it to associate the configfs entry to an actual EPC device.
+		The list of valid entries for this field can be obtained from
+			ls /sys/class/pci_epc/
+
+	*) epf: Directory that contains all the endpoint functions. The name
+		of the created directory determines the driver this particular
+		epf device will be bound to. The name can be obtained either
+		from the function binding documentation [4] or
+			ls /sys/bus/pci-epf/drivers
+
+		If more than one endpoint function device has to be bound to
+		the same driver, then the directory should be created using
+		the following notation
+			mkdir <name>.<num>
+
+*) Creating configfs entry for EPF
+
+Any directory created inside *epf* directory represents an EPF device. In the
+above directory structure, [3] represents an EPF device. It 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 directory is created inside epf directory.)
+
+        | vendorid
+        | deviceid
+        | revid
+        | progif_code
+        | subclass_code
+        | baseclass_code
+        | cache_line_size
+        | subsys_vendor_id
+        | subsys_id
+        | interrupt_pin
+
+The following entry identifies the function driver that is bound to the
+function device
+	| function
+
+[1] -> Documentation/PCI/endpoint/pci-endpoint.txt
+[4] -> Documentation/PCI/endpoint/function/binding/
-- 
1.7.9.5
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