1What:		/sys/devices/pnp0/<bus-num>/ppi/
2Date:		August 2012
3Kernel Version:	3.6
4Contact:	xiaoyan.zhang@intel.com
5Description:
6		This folder includes the attributes related with PPI (Physical
7		Presence Interface). Only if TPM is supported by BIOS, this
8		folder makes sence. 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		http://www.trustedcomputinggroup.org/
12
13What:		/sys/devices/pnp0/<bus-num>/ppi/version
14Date:		August 2012
15Contact:	xiaoyan.zhang@intel.com
16Description:
17		This attribute shows the version of the PPI supported by the
18		platform.
19		This file is readonly.
20
21What:		/sys/devices/pnp0/<bus-num>/ppi/request
22Date:		August 2012
23Contact:	xiaoyan.zhang@intel.com
24Description:
25		This attribute shows the request for an operation to be
26		executed in the pre-OS environment. It is the only input from
27		the OS to the pre-OS environment. The request should be an
28		integer value range from 1 to 160, and 0 means no request.
29		This file can be read and written.
30
31What:		/sys/devices/pnp0/00:<bus-num>/ppi/response
32Date:		August 2012
33Contact:	xiaoyan.zhang@intel.com
34Description:
35		This attribute shows the response to the most recent operation
36		request it acted upon. The format is "<request> <response num>
37		: <response description>".
38		This file is readonly.
39
40What:		/sys/devices/pnp0/<bus-num>/ppi/transition_action
41Date:		August 2012
42Contact:	xiaoyan.zhang@intel.com
43Description:
44		This attribute shows the platform-specific action that should
45		take place in order to transition to the BIOS for execution of
46		a requested operation. The format is "<action num>: <action
47		description>".
48		This file is readonly.
49
50What:		/sys/devices/pnp0/<bus-num>/ppi/tcg_operations
51Date:		August 2012
52Contact:	xiaoyan.zhang@intel.com
53Description:
54		This attribute shows whether it is allowed to request an
55		operation to be executed in the pre-OS environment by the BIOS
56		for the requests defined by TCG, i.e. requests from 1 to 22.
57		The format is "<request> <status num>: <status description>".
58		This attribute is only supported by PPI version 1.2+.
59		This file is readonly.
60
61What:		/sys/devices/pnp0/<bus-num>/ppi/vs_operations
62Date:		August 2012
63Contact:	xiaoyan.zhang@intel.com
64Description:
65		This attribute shows whether it is allowed to request an
66		operation to be executed in the pre-OS environment by the BIOS
67		for the verdor specific requests, i.e. requests from 128 to
68		255. The format is same with tcg_operations. This attribute
69		is also only supported by PPI version 1.2+.
70		This file is readonly.
71