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author | Linus Torvalds <torvalds@g5.osdl.org> | 2006-01-09 18:41:42 -0800 |
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committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-01-09 18:41:42 -0800 |
commit | 977127174a7dff52d17faeeb4c4949a54221881f (patch) | |
tree | b05b9d18a1256d7ed97bdfb537213a8d70ccca57 /Documentation/filesystems | |
parent | 80c0531514516e43ae118ddf38424e06e5c3cb3c (diff) | |
parent | 93b47684f60cf25e8cefe19a21d94aa0257fdf36 (diff) | |
download | kernel_samsung_smdk4412-977127174a7dff52d17faeeb4c4949a54221881f.zip kernel_samsung_smdk4412-977127174a7dff52d17faeeb4c4949a54221881f.tar.gz kernel_samsung_smdk4412-977127174a7dff52d17faeeb4c4949a54221881f.tar.bz2 |
Merge master.kernel.org:/pub/scm/linux/kernel/git/gregkh/pci-2.6
Diffstat (limited to 'Documentation/filesystems')
-rw-r--r-- | Documentation/filesystems/sysfs-pci.txt | 21 |
1 files changed, 15 insertions, 6 deletions
diff --git a/Documentation/filesystems/sysfs-pci.txt b/Documentation/filesystems/sysfs-pci.txt index 988a62f..7ba2baa 100644 --- a/Documentation/filesystems/sysfs-pci.txt +++ b/Documentation/filesystems/sysfs-pci.txt @@ -1,4 +1,5 @@ Accessing PCI device resources through sysfs +-------------------------------------------- sysfs, usually mounted at /sys, provides access to PCI resources on platforms that support it. For example, a given bus might look like this: @@ -47,14 +48,21 @@ files, each with their own function. binary - file contains binary data cpumask - file contains a cpumask type -The read only files are informational, writes to them will be ignored. -Writable files can be used to perform actions on the device (e.g. changing -config space, detaching a device). mmapable files are available via an -mmap of the file at offset 0 and can be used to do actual device programming -from userspace. Note that some platforms don't support mmapping of certain -resources, so be sure to check the return value from any attempted mmap. +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 +actions on the device (e.g. changing config space, detaching a device). +mmapable files are available via an mmap of the file at offset 0 and can be +used to do actual device programming from userspace. Note that some platforms +don't support mmapping of certain resources, so be sure to check the return +value from any attempted mmap. + +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 +should write the string "1" to the file to enable it before attempting a read +call, and disable it following the access by writing "0" to the file. Accessing legacy resources through sysfs +---------------------------------------- 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 heirarchy, @@ -75,6 +83,7 @@ simply dereference the returned pointer (after checking for errors of course) to access legacy memory space. Supporting PCI access on new platforms +-------------------------------------- In order to support PCI resource mapping as described above, Linux platform code must define HAVE_PCI_MMAP and provide a pci_mmap_page_range function. |