Commit 28bcadf0 authored by Mauro Carvalho Chehab's avatar Mauro Carvalho Chehab Committed by Jonathan Corbet

docs: filesystems: convert sysfs-pci.txt to ReST

- Add a SPDX header;
- Adjust document title;
- Some whitespace fixes and new line breaks;
- Mark literal blocks as such;
- Add table markups;
- Add it to filesystems/index.rst.
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/2a9d307753c97d1a843341a2ef1993d43a407ded.1588021877.git.mchehab+huawei@kernel.orgSigned-off-by: default avatarJonathan Corbet <corbet@lwn.net>
parent e2975d7c
...@@ -34,6 +34,7 @@ algorithms work. ...@@ -34,6 +34,7 @@ algorithms work.
quota quota
seq_file seq_file
sharedsubtree sharedsubtree
sysfs-pci
automount-support automount-support
......
.. SPDX-License-Identifier: GPL-2.0
============================================
Accessing PCI device resources through sysfs Accessing PCI device resources through sysfs
-------------------------------------------- ============================================
sysfs, usually mounted at /sys, provides access to PCI resources on platforms sysfs, usually mounted at /sys, provides access to PCI resources on platforms
that support it. For example, a given bus might look like this: that support it. For example, a given bus might look like this::
/sys/devices/pci0000:17 /sys/devices/pci0000:17
|-- 0000:17:00.0 |-- 0000:17:00.0
...@@ -30,8 +33,9 @@ This bus contains a single function device in slot 0. The domain and bus ...@@ -30,8 +33,9 @@ This bus contains a single function device in slot 0. The domain and bus
numbers are reproduced for convenience. Under the device directory are several numbers are reproduced for convenience. Under the device directory are several
files, each with their own function. files, each with their own function.
=================== =====================================================
file function file function
---- -------- =================== =====================================================
class PCI class (ascii, ro) class PCI class (ascii, ro)
config PCI config space (binary, rw) config PCI config space (binary, rw)
device PCI device (ascii, ro) device PCI device (ascii, ro)
...@@ -40,13 +44,16 @@ files, each with their own function. ...@@ -40,13 +44,16 @@ files, each with their own function.
local_cpus nearby CPU mask (cpumask, ro) local_cpus nearby CPU mask (cpumask, ro)
remove remove device from kernel's list (ascii, wo) remove remove device from kernel's list (ascii, wo)
resource PCI resource host addresses (ascii, ro) resource PCI resource host addresses (ascii, ro)
resource0..N PCI resource N, if present (binary, mmap, rw[1]) resource0..N PCI resource N, if present (binary, mmap, rw\ [1]_)
resource0_wc..N_wc PCI WC map resource N, if prefetchable (binary, mmap) resource0_wc..N_wc PCI WC map resource N, if prefetchable (binary, mmap)
revision PCI revision (ascii, ro) revision PCI revision (ascii, ro)
rom PCI ROM resource, if present (binary, ro) rom PCI ROM resource, if present (binary, ro)
subsystem_device PCI subsystem device (ascii, ro) subsystem_device PCI subsystem device (ascii, ro)
subsystem_vendor PCI subsystem vendor (ascii, ro) subsystem_vendor PCI subsystem vendor (ascii, ro)
vendor PCI vendor (ascii, ro) vendor PCI vendor (ascii, ro)
=================== =====================================================
::
ro - read only file ro - read only file
rw - file is readable and writable rw - file is readable and writable
...@@ -56,7 +63,7 @@ files, each with their own function. ...@@ -56,7 +63,7 @@ files, each with their own function.
binary - file contains binary data binary - file contains binary data
cpumask - file contains a cpumask type cpumask - file contains a cpumask type
[1] rw for RESOURCE_IO (I/O port) regions only .. [1] rw for RESOURCE_IO (I/O port) regions only
The read only files are informational, writes to them will be ignored, with The read only files are informational, writes to them will be ignored, with
the exception of the 'rom' file. Writable files can be used to perform the exception of the 'rom' file. Writable files can be used to perform
...@@ -67,11 +74,11 @@ don't support mmapping of certain resources, so be sure to check the return ...@@ -67,11 +74,11 @@ don't support mmapping of certain resources, so be sure to check the return
value from any attempted mmap. The most notable of these are I/O port value from any attempted mmap. The most notable of these are I/O port
resources, which also provide read/write access. resources, which also provide read/write access.
The 'enable' file provides a counter that indicates how many times the device The 'enable' file provides a counter that indicates how many times the device
has been enabled. If the 'enable' file currently returns '4', and a '1' is has been enabled. If the 'enable' file currently returns '4', and a '1' is
echoed into it, it will then return '5'. Echoing a '0' into it will decrease echoed into it, it will then return '5'. Echoing a '0' into it will decrease
the count. Even when it returns to 0, though, some of the initialisation the count. Even when it returns to 0, though, some of the initialisation
may not be reversed. may not be reversed.
The 'rom' file is special in that it provides read-only access to the device's The 'rom' file is special in that it provides read-only access to the device's
ROM file, if available. It's disabled by default, however, so applications ROM file, if available. It's disabled by default, however, so applications
...@@ -93,7 +100,7 @@ Accessing legacy resources through sysfs ...@@ -93,7 +100,7 @@ Accessing legacy resources through sysfs
Legacy I/O port and ISA memory resources are also provided in sysfs if the Legacy I/O port and ISA memory resources are also provided in sysfs if the
underlying platform supports them. They're located in the PCI class hierarchy, underlying platform supports them. They're located in the PCI class hierarchy,
e.g. e.g.::
/sys/class/pci_bus/0000:17/ /sys/class/pci_bus/0000:17/
|-- bridge -> ../../../devices/pci0000:17 |-- bridge -> ../../../devices/pci0000:17
......
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