ext4: Use tracepoints for mb_history trace file

[safe/jmp/linux-2.6] / Documentation / filesystems / sysfs-pci.txt

diff --git a/Documentation/filesystems/sysfs-pci.txt b/Documentation/filesystems/sysfs-pci.txt
index e97d024..85354b3 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:


@@ -7,10 +8,11 @@ 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
      |   |-- device

+     |   |-- enable

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

+     |   |-- remove

      |   |-- resource
      |   |-- resource0
      |   |-- resource1
      |   |-- resource
      |   |-- resource0
      |   |-- resource1


@@ -19,7 +21,7 @@ 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).


@@ -31,12 +33,14 @@ 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)
        device             PCI device (ascii, ro)

+       enable             Whether the device is enabled (ascii, rw)

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

+       remove             remove device from kernel's list (ascii, wo)

        resource                   PCI resource host addresses (ascii, ro)
        resource0..N       PCI resource N, if present (binary, mmap)
        resource                   PCI resource host addresses (ascii, ro)
        resource0..N       PCI resource N, if present (binary, mmap)

+       resource0_wc..N_wc  PCI WC map resource N, if prefetchable (binary, mmap)

        rom                PCI ROM resource, if present (binary, ro)
        subsystem_device           PCI subsystem device (ascii, ro)
        subsystem_vendor           PCI subsystem vendor (ascii, ro)
        rom                PCI ROM resource, if present (binary, ro)
        subsystem_device           PCI subsystem device (ascii, ro)
        subsystem_vendor           PCI subsystem vendor (ascii, ro)


@@ -44,22 +48,46 @@ files, each with their own function.
 
   ro - read only file
   rw - file is readable and writable
 
   ro - read only file
   rw - file is readable and writable

+  wo - write only file

   mmap - file is mmapable
   ascii - file contains ascii text
   binary - file contains binary data
   cpumask - file contains a cpumask type
 
   mmap - file is mmapable
   ascii - file contains ascii text
   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 '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
+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
+may not be reversed.  
+
+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.  Note
+that the device must be enabled for a rom read to return data successfully.
+In the event a driver is not bound to the device, it can be enabled using the
+'enable' file, documented above.
+
+The 'remove' file is used to remove the PCI device, by writing a non-zero
+integer to the file.  This does not involve any kind of hot-plug functionality,
+e.g. powering off the device.  The device is removed from the kernel's list of
+PCI devices, the sysfs directory for it is removed, and the device will be
+removed from any drivers attached to it. Removal of PCI root buses is
+disallowed.

 
 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
 
 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,
+underlying platform supports them.  They're located in the PCI class hierarchy,

 e.g.
 
        /sys/class/pci_bus/0000:17/
 e.g.
 
        /sys/class/pci_bus/0000:17/


@@ -77,6 +105,7 @@ 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 +114,4 @@ 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.