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From:   Kishon Vijay Abraham I <kishon@ti.com>
To:     Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
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CC:     Jonathan Corbet <corbet@lwn.net>, Arnd Bergmann <arnd@arndb.de>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        <linux-pci@vger.kernel.org>, <linux-doc@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>, <devicetree@vger.kernel.org>,
        <linux-renesas-soc@vger.kernel.org>,
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        Lokesh Vutla <lokeshvutla@ti.com>
Subject: [PATCH v6 7/7] Documentation: PCI: endpoint/pci-endpoint-cfs: Guide to use SR-IOV
Date:   Mon, 17 May 2021 13:17:23 +0530
Message-ID: <20210517074723.10212-8-kishon@ti.com>
In-Reply-To: <20210517074723.10212-1-kishon@ti.com>
References: <20210517074723.10212-1-kishon@ti.com>
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Add Documentation to help users use PCI endpoint to create virtual
functions using configfs. An endpoint function is designated as a
virtual endpoint function device when it is linked to a physical
endpoint function device (instead of a endpoint controller).

Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
---
 Documentation/PCI/endpoint/pci-endpoint-cfs.rst | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/Documentation/PCI/endpoint/pci-endpoint-cfs.rst b/Documentation/PCI/endpoint/pci-endpoint-cfs.rst
index 696f8eeb4738..56fb33c5e8fd 100644
--- a/Documentation/PCI/endpoint/pci-endpoint-cfs.rst
+++ b/Documentation/PCI/endpoint/pci-endpoint-cfs.rst
@@ -43,6 +43,7 @@ entries corresponding to EPF driver will be created by the EPF core.
 		.. <EPF Driver1>/
 			... <EPF Device 11>/
 			... <EPF Device 21>/
+			... <EPF Device 31>/
 		.. <EPF Driver2>/
 			... <EPF Device 12>/
 			... <EPF Device 22>/
@@ -68,6 +69,7 @@ created)
 				... subsys_vendor_id
 				... subsys_id
 				... interrupt_pin
+			        ... <Symlink EPF Device 31>/
                                 ... primary/
 			                ... <Symlink EPC Device1>/
                                 ... secondary/
@@ -79,6 +81,13 @@ 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
 ==========
 
@@ -98,7 +107,8 @@ entries corresponding to EPC device will be created by the EPC core.
 
 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.
+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
-- 
2.17.1