xref: /openbmc/linux/include/xen/interface/io/tpmif.h (revision e8dc73c9)
1 /******************************************************************************
2  * tpmif.h
3  *
4  * TPM I/O interface for Xen guest OSes, v2
5  *
6  * This file is in the public domain.
7  *
8  */
9 
10 #ifndef __XEN_PUBLIC_IO_TPMIF_H__
11 #define __XEN_PUBLIC_IO_TPMIF_H__
12 
13 /*
14  * Xenbus state machine
15  *
16  * Device open:
17  *   1. Both ends start in XenbusStateInitialising
18  *   2. Backend transitions to InitWait (frontend does not wait on this step)
19  *   3. Frontend populates ring-ref, event-channel, feature-protocol-v2
20  *   4. Frontend transitions to Initialised
21  *   5. Backend maps grant and event channel, verifies feature-protocol-v2
22  *   6. Backend transitions to Connected
23  *   7. Frontend verifies feature-protocol-v2, transitions to Connected
24  *
25  * Device close:
26  *   1. State is changed to XenbusStateClosing
27  *   2. Frontend transitions to Closed
28  *   3. Backend unmaps grant and event, changes state to InitWait
29  */
30 
31 enum vtpm_shared_page_state {
32 	VTPM_STATE_IDLE,         /* no contents / vTPM idle / cancel complete */
33 	VTPM_STATE_SUBMIT,       /* request ready / vTPM working */
34 	VTPM_STATE_FINISH,       /* response ready / vTPM idle */
35 	VTPM_STATE_CANCEL,       /* cancel requested / vTPM working */
36 };
37 /* The backend should only change state to IDLE or FINISH, while the
38  * frontend should only change to SUBMIT or CANCEL. */
39 
40 
41 struct vtpm_shared_page {
42 	uint32_t length;         /* request/response length in bytes */
43 
44 	uint8_t state;           /* enum vtpm_shared_page_state */
45 	uint8_t locality;        /* for the current request */
46 	uint8_t pad;
47 
48 	uint8_t nr_extra_pages;  /* extra pages for long packets; may be zero */
49 	uint32_t extra_pages[]; /* grant IDs; length in nr_extra_pages */
50 };
51 
52 #endif
53