Documentation/ABI/testing/sysfs-driver-ppi

   1 What:           /sys/class/tpm/tpmX/ppi/
   2 Date:           August 2012
   3 Kernel Version: 3.6
   4 Contact:        xiaoyan.zhang@intel.com
   5 Description:
   6                 This folder includes the attributes related with PPI (Physical
   7                 Presence Interface). Only if TPM is supported by BIOS, this
   8                 folder makes sense. The folder path can be got by command
   9                 'find /sys/ -name 'pcrs''. For the detail information of PPI,
  10                 please refer to the PPI specification from
  11
  12                 http://www.trustedcomputinggroup.org/
  13
  14                 In Linux 4.2 ppi was moved to the character device directory.
  15                 A symlink from tpmX/device/ppi to tpmX/ppi to provide backwards
  16                 compatibility.
  17
  18 What:           /sys/class/tpm/tpmX/ppi/version
  19 Date:           August 2012
  20 Contact:        xiaoyan.zhang@intel.com
  21 Description:
  22                 This attribute shows the version of the PPI supported by the
  23                 platform.
  24                 This file is readonly.
  25
  26 What:           /sys/class/tpm/tpmX/ppi/request
  27 Date:           August 2012
  28 Contact:        xiaoyan.zhang@intel.com
  29 Description:
  30                 This attribute shows the request for an operation to be
  31                 executed in the pre-OS environment. It is the only input from
  32                 the OS to the pre-OS environment. The request should be an
  33                 integer value range from 1 to 160, and 0 means no request.
  34                 This file can be read and written.
  35
  36 What:           /sys/class/tpm/tpmX/ppi/response
  37 Date:           August 2012
  38 Contact:        xiaoyan.zhang@intel.com
  39 Description:
  40                 This attribute shows the response to the most recent operation
  41                 request it acted upon. The format is "<request> <response num>
  42                 : <response description>".
  43                 This file is readonly.
  44
  45 What:           /sys/class/tpm/tpmX/ppi/transition_action
  46 Date:           August 2012
  47 Contact:        xiaoyan.zhang@intel.com
  48 Description:
  49                 This attribute shows the platform-specific action that should
  50                 take place in order to transition to the BIOS for execution of
  51                 a requested operation. The format is "<action num>: <action
  52                 description>".
  53                 This file is readonly.
  54
  55 What:           /sys/class/tpm/tpmX/ppi/tcg_operations
  56 Date:           August 2012
  57 Contact:        xiaoyan.zhang@intel.com
  58 Description:
  59                 This attribute shows whether it is allowed to request an
  60                 operation to be executed in the pre-OS environment by the BIOS
  61                 for the requests defined by TCG, i.e. requests from 1 to 22.
  62                 The format is "<request> <status num>: <status description>".
  63                 This attribute is only supported by PPI version 1.2+.
  64                 This file is readonly.
  65
  66 What:           /sys/class/tpm/tpmX/ppi/vs_operations
  67 Date:           August 2012
  68 Contact:        xiaoyan.zhang@intel.com
  69 Description:
  70                 This attribute shows whether it is allowed to request an
  71                 operation to be executed in the pre-OS environment by the BIOS
  72                 for the verdor specific requests, i.e. requests from 128 to
  73                 255. The format is same with tcg_operations. This attribute
  74                 is also only supported by PPI version 1.2+.
  75                 This file is readonly.