xen/kbdif: update protocol description (8ec9dd0e) · Commits · github.com / kvm-riscv / linux

include/xen/interface/io/kbdif.h

+221 −27

Original line number	Diff line number	Diff line
		@@ -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__ */