/******************************************************************************
* tpmif.h
*
* TPM I/O interface for Xen guest OSes, v2
*
* This file is in the public domain.
*
*/

#ifndef __XEN_PUBLIC_IO_TPMIF_H__
#define __XEN_PUBLIC_IO_TPMIF_H__

/*
* Xenbus state machine
*
* Device open:
* 1. Both ends start in XenbusStateInitialising
* 2. Backend transitions to InitWait (frontend does not wait on this step)
* 3. Frontend populates ring-ref, event-channel, feature-protocol-v2
* 4. Frontend transitions to Initialised
* 5. Backend maps grant and event channel, verifies feature-protocol-v2
* 6. Backend transitions to Connected
* 7. Frontend verifies feature-protocol-v2, transitions to Connected
*
* Device close:
* 1. State is changed to XenbusStateClosing
* 2. Frontend transitions to Closed
* 3. Backend unmaps grant and event, changes state to InitWait
*/

enum vtpm_shared_page_state {
VTPM_STATE_IDLE, /* no contents / vTPM idle / cancel complete */
VTPM_STATE_SUBMIT, /* request ready / vTPM working */
VTPM_STATE_FINISH, /* response ready / vTPM idle */
VTPM_STATE_CANCEL, /* cancel requested / vTPM working */
};
/* The backend should only change state to IDLE or FINISH, while the
* frontend should only change to SUBMIT or CANCEL. */


struct vtpm_shared_page {
uint32_t length; /* request/response length in bytes */

uint8_t state; /* enum vtpm_shared_page_state */
uint8_t locality; /* for the current request */
uint8_t pad;

uint8_t nr_extra_pages; /* extra pages for long packets; may be zero */
uint32_t extra_pages[0]; /* grant IDs; length in nr_extra_pages */
};

#endif