From 2c3c1048746a4622d8c89a29670120dc8fab93c4 Mon Sep 17 00:00:00 2001
From: Daniel Baumann <daniel.baumann@progress-linux.org>
Date: Sun, 7 Apr 2024 20:49:45 +0200
Subject: Adding upstream version 6.1.76.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
---
 Documentation/PCI/endpoint/pci-endpoint-cfs.rst | 138 ++++++++++++++++++++++++
 1 file changed, 138 insertions(+)
 create mode 100644 Documentation/PCI/endpoint/pci-endpoint-cfs.rst

(limited to 'Documentation/PCI/endpoint/pci-endpoint-cfs.rst')

diff --git a/Documentation/PCI/endpoint/pci-endpoint-cfs.rst b/Documentation/PCI/endpoint/pci-endpoint-cfs.rst
new file mode 100644
index 000000000..fb73345cf
--- /dev/null
+++ b/Documentation/PCI/endpoint/pci-endpoint-cfs.rst
@@ -0,0 +1,138 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+=======================================
+Configuring PCI Endpoint Using CONFIGFS
+=======================================
+
+:Author: Kishon Vijay Abraham I <kishon@ti.com>
+
+The PCI Endpoint Core exposes configfs entry (pci_ep) to configure the
+PCI endpoint function and to bind the endpoint function
+with the endpoint controller. (For introducing other mechanisms to
+configure the PCI Endpoint Function refer to [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 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 Device 31>/
+		.. <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
+			        ... <Symlink EPF Device 31>/
+                                ... primary/
+			                ... <Symlink EPC Device1>/
+                                ... secondary/
+			                ... <Symlink EPC Device2>/
+
+If an EPF device has to be associated with 2 EPCs (like in the case of
+Non-transparent bridge), symlink of endpoint controller connected to primary
+interface should be added in 'primary' directory and symlink of endpoint
+controller connected to secondary interface should be added in 'secondary'
+directory.
+
+The <EPF Device> directory can have a list of symbolic links
+(<Symlink EPF Device 31>) to other <EPF Device>. These symbolic links should
+be created by the user to represent the virtual functions that are bound to
+the physical function. In the above directory structure <EPF Device 11> is a
+physical function and <EPF Device 31> is a virtual function. An EPF device once
+it's linked to another EPF device, cannot be linked to a EPC device.
+
+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. Only <EPF Device>
+that represents a physical function can be linked to a EPC 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.rst
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