[PATCH] Update udf documentation to reflect current state of read/write support

[linux-2.6-omap-h63xx.git] / Documentation / filesystems / sysfs-pci.txt

diff --git a/Documentation/filesystems/sysfs-pci.txt b/Documentation/filesystems/sysfs-pci.txt
index e97d024eae77e5fa9f1ac338074a24baf42680e5..7ba2baa165ffdc547b292708a4578a2c7800abf8 100644 (file)
--- a/Documentation/filesystems/sysfs-pci.txt
+++ b/Documentation/filesystems/sysfs-pci.txt
@@ -1,4 +1,5 @@
 Accessing PCI device resources through sysfs
 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:
 
 sysfs, usually mounted at /sys, provides access to PCI resources on platforms
 that support it.  For example, a given bus might look like this:


@@ -7,7 +8,6 @@ that support it.  For example, a given bus might look like this:
      |-- 0000:17:00.0
      |   |-- class
      |   |-- config
      |-- 0000:17:00.0
      |   |-- class
      |   |-- config

-     |   |-- detach_state

      |   |-- device
      |   |-- irq
      |   |-- local_cpus
      |   |-- device
      |   |-- irq
      |   |-- local_cpus


@@ -19,7 +19,7 @@ that support it.  For example, a given bus might look like this:
      |   |-- subsystem_device
      |   |-- subsystem_vendor
      |   `-- vendor
      |   |-- subsystem_device
      |   |-- subsystem_vendor
      |   `-- vendor

-     `-- detach_state
+     `-- ...

 
 The topmost element describes the PCI domain and bus number.  In this case,
 the domain number is 0000 and the bus number is 17 (both values are in hex).
 
 The topmost element describes the PCI domain and bus number.  In this case,
 the domain number is 0000 and the bus number is 17 (both values are in hex).


@@ -31,7 +31,6 @@ files, each with their own function.
        ----               --------
        class              PCI class (ascii, ro)
        config             PCI config space (binary, rw)
        ----               --------
        class              PCI class (ascii, ro)
        config             PCI config space (binary, rw)

-       detach_state       connection status (bool, rw)

        device             PCI device (ascii, ro)
        irq                IRQ number (ascii, ro)
        local_cpus         nearby CPU mask (cpumask, ro)
        device             PCI device (ascii, ro)
        irq                IRQ number (ascii, ro)
        local_cpus         nearby CPU mask (cpumask, ro)


@@ -49,14 +48,21 @@ files, each with their own function.
   binary - file contains binary data
   cpumask - file contains a cpumask type
 
   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
 
 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,
 
 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,


@@ -77,6 +83,7 @@ simply dereference the returned pointer (after checking for errors of course)
 to access legacy memory space.
 
 Supporting PCI access on new platforms
 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.
 
 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.


@@ -85,4 +92,4 @@ useful return codes should be provided.
 
 Legacy resources are protected by the HAVE_PCI_LEGACY define.  Platforms
 wishing to support legacy functionality should define it and provide
 
 Legacy resources are protected by the HAVE_PCI_LEGACY define.  Platforms
 wishing to support legacy functionality should define it and provide

-pci_legacy_read, pci_legacy_write and pci_mmap_legacy_page_range functions.
\ No newline at end of file
+pci_legacy_read, pci_legacy_write and pci_mmap_legacy_page_range functions.