Commit 8ec9dd0e authored by Oleksandr Andrushchenko's avatar Oleksandr Andrushchenko Committed by Juergen Gross

xen/kbdif: update protocol description

The patch clarifies the protocol that is used by the PV keyboard
drivers.
Signed-off-by: default avatarOleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
Acked-by: default avatarJuergen Gross <jgross@suse.com>
Signed-off-by: default avatarJuergen Gross <jgross@suse.com>
parent 7f25483a
......@@ -26,43 +26,223 @@
#ifndef __XEN_PUBLIC_IO_KBDIF_H__
#define __XEN_PUBLIC_IO_KBDIF_H__
/* In events (backend -> frontend) */
/*
*****************************************************************************
* Feature and Parameter Negotiation
*****************************************************************************
*
* The two halves of a para-virtual driver utilize nodes within
* XenStore to communicate capabilities and to negotiate operating parameters.
* This section enumerates these nodes which reside in the respective front and
* backend portions of XenStore, following XenBus convention.
*
* All data in XenStore is stored as strings. Nodes specifying numeric
* values are encoded in decimal. Integer value ranges listed below are
* expressed as fixed sized integer types capable of storing the conversion
* of a properly formated node string, without loss of information.
*
*****************************************************************************
* Backend XenBus Nodes
*****************************************************************************
*
*---------------------------- Features supported ----------------------------
*
* Capable backend advertises supported features by publishing
* corresponding entries in XenStore and puts 1 as the value of the entry.
* If a feature is not supported then 0 must be set or feature entry omitted.
*
* feature-abs-pointer
* Values: <uint>
*
* Backends, which support reporting of absolute coordinates for pointer
* device should set this to 1.
*
*------------------------- Pointer Device Parameters ------------------------
*
* width
* Values: <uint>
*
* Maximum X coordinate (width) to be used by the frontend
* while reporting input events, pixels, [0; UINT32_MAX].
*
* height
* Values: <uint>
*
* Maximum Y coordinate (height) to be used by the frontend
* while reporting input events, pixels, [0; UINT32_MAX].
*
*****************************************************************************
* Frontend XenBus Nodes
*****************************************************************************
*
*------------------------------ Feature request -----------------------------
*
* Capable frontend requests features from backend via setting corresponding
* entries to 1 in XenStore. Requests for features not advertised as supported
* by the backend have no effect.
*
* request-abs-pointer
* Values: <uint>
*
* Request backend to report absolute pointer coordinates
* (XENKBD_TYPE_POS) instead of relative ones (XENKBD_TYPE_MOTION).
*
*----------------------- Request Transport Parameters -----------------------
*
* event-channel
* Values: <uint>
*
* The identifier of the Xen event channel used to signal activity
* in the ring buffer.
*
* page-gref
* Values: <uint>
*
* The Xen grant reference granting permission for the backend to map
* a sole page in a single page sized event ring buffer.
*
* page-ref
* Values: <uint>
*
* OBSOLETE, not recommended for use.
* PFN of the shared page.
*/
/*
* Frontends should ignore unknown in events.
* EVENT CODES.
*/
/* Pointer movement event */
#define XENKBD_TYPE_MOTION 1
/* Event type 2 currently not used */
/* Key event (includes pointer buttons) */
#define XENKBD_TYPE_RESERVED 2
#define XENKBD_TYPE_KEY 3
#define XENKBD_TYPE_POS 4
/*
* Pointer position event
* Capable backend sets feature-abs-pointer in xenstore.
* Frontend requests ot instead of XENKBD_TYPE_MOTION by setting
* request-abs-update in xenstore.
* CONSTANTS, XENSTORE FIELD AND PATH NAME STRINGS, HELPERS.
*/
#define XENKBD_DRIVER_NAME "vkbd"
#define XENKBD_FIELD_FEAT_ABS_POINTER "feature-abs-pointer"
#define XENKBD_FIELD_REQ_ABS_POINTER "request-abs-pointer"
#define XENKBD_FIELD_RING_GREF "page-gref"
#define XENKBD_FIELD_EVT_CHANNEL "event-channel"
#define XENKBD_FIELD_WIDTH "width"
#define XENKBD_FIELD_HEIGHT "height"
/* OBSOLETE, not recommended for use */
#define XENKBD_FIELD_RING_REF "page-ref"
/*
*****************************************************************************
* Description of the protocol between frontend and backend driver.
*****************************************************************************
*
* The two halves of a Para-virtual driver communicate with
* each other using a shared page and an event channel.
* Shared page contains a ring with event structures.
*
* All reserved fields in the structures below must be 0.
*
*****************************************************************************
* Backend to frontend events
*****************************************************************************
*
* Frontends should ignore unknown in events.
* All event packets have the same length (40 octets)
* All event packets have common header:
*
* 0 octet
* +-----------------+
* | type |
* +-----------------+
* type - uint8_t, event code, XENKBD_TYPE_???
*
*
* Pointer relative movement event
* 0 1 2 3 octet
* +----------------+----------------+----------------+----------------+
* | _TYPE_MOTION | reserved | 4
* +----------------+----------------+----------------+----------------+
* | rel_x | 8
* +----------------+----------------+----------------+----------------+
* | rel_y | 12
* +----------------+----------------+----------------+----------------+
* | rel_z | 16
* +----------------+----------------+----------------+----------------+
* | reserved | 20
* +----------------+----------------+----------------+----------------+
* |/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/|
* +----------------+----------------+----------------+----------------+
* | reserved | 40
* +----------------+----------------+----------------+----------------+
*
* rel_x - int32_t, relative X motion
* rel_y - int32_t, relative Y motion
* rel_z - int32_t, relative Z motion (wheel)
*/
#define XENKBD_TYPE_POS 4
struct xenkbd_motion {
uint8_t type; /* XENKBD_TYPE_MOTION */
int32_t rel_x; /* relative X motion */
int32_t rel_y; /* relative Y motion */
int32_t rel_z; /* relative Z motion (wheel) */
uint8_t type;
int32_t rel_x;
int32_t rel_y;
int32_t rel_z;
};
/*
* Key event (includes pointer buttons)
* 0 1 2 3 octet
* +----------------+----------------+----------------+----------------+
* | _TYPE_KEY | pressed | reserved | 4
* +----------------+----------------+----------------+----------------+
* | keycode | 8
* +----------------+----------------+----------------+----------------+
* | reserved | 12
* +----------------+----------------+----------------+----------------+
* |/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/|
* +----------------+----------------+----------------+----------------+
* | reserved | 40
* +----------------+----------------+----------------+----------------+
*
* pressed - uint8_t, 1 if pressed; 0 otherwise
* keycode - uint32_t, KEY_* from linux/input.h
*/
struct xenkbd_key {
uint8_t type; /* XENKBD_TYPE_KEY */
uint8_t pressed; /* 1 if pressed; 0 otherwise */
uint32_t keycode; /* KEY_* from linux/input.h */
uint8_t type;
uint8_t pressed;
uint32_t keycode;
};
/*
* Pointer absolute position event
* 0 1 2 3 octet
* +----------------+----------------+----------------+----------------+
* | _TYPE_POS | reserved | 4
* +----------------+----------------+----------------+----------------+
* | abs_x | 8
* +----------------+----------------+----------------+----------------+
* | abs_y | 12
* +----------------+----------------+----------------+----------------+
* | rel_z | 16
* +----------------+----------------+----------------+----------------+
* | reserved | 20
* +----------------+----------------+----------------+----------------+
* |/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/|
* +----------------+----------------+----------------+----------------+
* | reserved | 40
* +----------------+----------------+----------------+----------------+
*
* abs_x - int32_t, absolute X position (in FB pixels)
* abs_y - int32_t, absolute Y position (in FB pixels)
* rel_z - int32_t, relative Z motion (wheel)
*/
struct xenkbd_position {
uint8_t type; /* XENKBD_TYPE_POS */
int32_t abs_x; /* absolute X position (in FB pixels) */
int32_t abs_y; /* absolute Y position (in FB pixels) */
int32_t rel_z; /* relative Z motion (wheel) */
uint8_t type;
int32_t abs_x;
int32_t abs_y;
int32_t rel_z;
};
#define XENKBD_IN_EVENT_SIZE 40
......@@ -75,12 +255,22 @@ union xenkbd_in_event {
char pad[XENKBD_IN_EVENT_SIZE];
};
/* Out events (frontend -> backend) */
/*
*****************************************************************************
* Frontend to backend events
*****************************************************************************
*
* Out events may be sent only when requested by backend, and receipt
* of an unknown out event is an error.
* No out events currently defined.
* All event packets have the same length (40 octets)
* All event packets have common header:
* 0 octet
* +-----------------+
* | type |
* +-----------------+
* type - uint8_t, event code
*/
#define XENKBD_OUT_EVENT_SIZE 40
......@@ -90,7 +280,11 @@ union xenkbd_out_event {
char pad[XENKBD_OUT_EVENT_SIZE];
};
/* shared page */
/*
*****************************************************************************
* Shared page
*****************************************************************************
*/
#define XENKBD_IN_RING_SIZE 2048
#define XENKBD_IN_RING_LEN (XENKBD_IN_RING_SIZE / XENKBD_IN_EVENT_SIZE)
......@@ -113,4 +307,4 @@ struct xenkbd_page {
uint32_t out_cons, out_prod;
};
#endif
#endif /* __XEN_PUBLIC_IO_KBDIF_H__ */
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