WIP FPC-III support
[linux/fpc-iii.git] / Documentation / ABI / testing / sysfs-firmware-gsmi
blob7a558354c1ee0182d354fe3c490d0c571abf96cb
1 What:           /sys/firmware/gsmi
2 Date:           March 2011
3 Contact:        Mike Waychison <mikew@google.com>
4 Description:
5                 Some servers used internally at Google have firmware
6                 that provides callback functionality via explicit SMI
7                 triggers.  Some of the callbacks are similar to those
8                 provided by the EFI runtime services page, but due to
9                 historical reasons this different entry-point has been
10                 used.
12                 The gsmi driver implements the kernel's abstraction for
13                 these firmware callbacks.  Currently, this functionality
14                 is limited to handling the system event log and getting
15                 access to EFI-style variables stored in nvram.
17                 Layout:
19                 /sys/firmware/gsmi/vars:
21                         This directory has the same layout (and
22                         underlying implementation as /sys/firmware/efi/vars.
23                         See `Documentation/ABI/*/sysfs-firmware-efi-vars`
24                         for more information on how to interact with
25                         this structure.
27                 /sys/firmware/gsmi/append_to_eventlog - write-only:
29                         This file takes a binary blob and passes it onto
30                         the firmware to be timestamped and appended to
31                         the system eventlog.  The binary format is
32                         interpreted by the firmware and may change from
33                         platform to platform.  The only kernel-enforced
34                         requirement is that the blob be prefixed with a
35                         32bit host-endian type used as part of the
36                         firmware call.
38                 /sys/firmware/gsmi/clear_config - write-only:
40                         Writing any value to this file will cause the
41                         entire firmware configuration to be reset to
42                         "factory defaults".  Callers should assume that
43                         a reboot is required for the configuration to be
44                         cleared.
46                 /sys/firmware/gsmi/clear_eventlog - write-only:
48                         This file is used to clear out a portion/the
49                         whole of the system event log.  Values written
50                         should be values between 1 and 100 inclusive (in
51                         ASCII) representing the fraction of the log to
52                         clear.  Not all platforms support fractional
53                         clearing though, and this writes to this file
54                         will error out if the firmware doesn't like your
55                         submitted fraction.
57                         Callers should assume that a reboot is needed
58                         for this operation to complete.