Documentation/ABI/testing/sysfs-firmware-gsmi

   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.
  11
  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.
  16
  17                 Layout:
  18
  19                 /sys/firmware/gsmi/vars:
  20
  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.
  26
  27                 /sys/firmware/gsmi/append_to_eventlog - write-only:
  28
  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.
  37
  38                 /sys/firmware/gsmi/clear_config - write-only:
  39
  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.
  45
  46                 /sys/firmware/gsmi/clear_eventlog - write-only:
  47
  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.
  56
  57                         Callers should assume that a reboot is needed
  58                         for this operation to complete.