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xen/kbdif: update protocol description
The patch clarifies the protocol that is used by the PV keyboard drivers. Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com> Acked-by: Juergen Gross <jgross@suse.com> Signed-off-by: Juergen Gross <jgross@suse.com>
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Oleksandr Andrushchenko
Juergen Gross
parent
7f25483a88
commit
8ec9dd0e69
@ -26,43 +26,223 @@
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#ifndef __XEN_PUBLIC_IO_KBDIF_H__
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#define __XEN_PUBLIC_IO_KBDIF_H__
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/* In events (backend -> frontend) */
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/*
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*****************************************************************************
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* Feature and Parameter Negotiation
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*****************************************************************************
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*
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* The two halves of a para-virtual driver utilize nodes within
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* XenStore to communicate capabilities and to negotiate operating parameters.
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* This section enumerates these nodes which reside in the respective front and
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* backend portions of XenStore, following XenBus convention.
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*
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* All data in XenStore is stored as strings. Nodes specifying numeric
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* values are encoded in decimal. Integer value ranges listed below are
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* expressed as fixed sized integer types capable of storing the conversion
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* of a properly formated node string, without loss of information.
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*
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*****************************************************************************
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* Backend XenBus Nodes
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*****************************************************************************
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*
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*---------------------------- Features supported ----------------------------
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*
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* Capable backend advertises supported features by publishing
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* corresponding entries in XenStore and puts 1 as the value of the entry.
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* If a feature is not supported then 0 must be set or feature entry omitted.
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*
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* feature-abs-pointer
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* Values: <uint>
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*
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* Backends, which support reporting of absolute coordinates for pointer
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* device should set this to 1.
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*
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*------------------------- Pointer Device Parameters ------------------------
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*
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* width
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* Values: <uint>
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*
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* Maximum X coordinate (width) to be used by the frontend
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* while reporting input events, pixels, [0; UINT32_MAX].
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*
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* height
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* Values: <uint>
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*
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* Maximum Y coordinate (height) to be used by the frontend
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* while reporting input events, pixels, [0; UINT32_MAX].
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*
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*****************************************************************************
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* Frontend XenBus Nodes
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*****************************************************************************
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*
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*------------------------------ Feature request -----------------------------
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*
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* Capable frontend requests features from backend via setting corresponding
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* entries to 1 in XenStore. Requests for features not advertised as supported
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* by the backend have no effect.
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*
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* request-abs-pointer
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* Values: <uint>
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*
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* Request backend to report absolute pointer coordinates
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* (XENKBD_TYPE_POS) instead of relative ones (XENKBD_TYPE_MOTION).
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*
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*----------------------- Request Transport Parameters -----------------------
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*
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* event-channel
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* Values: <uint>
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*
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* The identifier of the Xen event channel used to signal activity
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* in the ring buffer.
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*
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* page-gref
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* Values: <uint>
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*
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* The Xen grant reference granting permission for the backend to map
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* a sole page in a single page sized event ring buffer.
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*
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* page-ref
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* Values: <uint>
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*
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* OBSOLETE, not recommended for use.
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* PFN of the shared page.
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*/
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/*
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* EVENT CODES.
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*/
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#define XENKBD_TYPE_MOTION 1
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#define XENKBD_TYPE_RESERVED 2
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#define XENKBD_TYPE_KEY 3
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#define XENKBD_TYPE_POS 4
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/*
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* CONSTANTS, XENSTORE FIELD AND PATH NAME STRINGS, HELPERS.
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*/
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#define XENKBD_DRIVER_NAME "vkbd"
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#define XENKBD_FIELD_FEAT_ABS_POINTER "feature-abs-pointer"
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#define XENKBD_FIELD_REQ_ABS_POINTER "request-abs-pointer"
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#define XENKBD_FIELD_RING_GREF "page-gref"
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#define XENKBD_FIELD_EVT_CHANNEL "event-channel"
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#define XENKBD_FIELD_WIDTH "width"
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#define XENKBD_FIELD_HEIGHT "height"
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/* OBSOLETE, not recommended for use */
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#define XENKBD_FIELD_RING_REF "page-ref"
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/*
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*****************************************************************************
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* Description of the protocol between frontend and backend driver.
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*****************************************************************************
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*
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* The two halves of a Para-virtual driver communicate with
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* each other using a shared page and an event channel.
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* Shared page contains a ring with event structures.
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*
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* All reserved fields in the structures below must be 0.
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*
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*****************************************************************************
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* Backend to frontend events
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*****************************************************************************
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*
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* Frontends should ignore unknown in events.
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* All event packets have the same length (40 octets)
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* All event packets have common header:
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*
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* 0 octet
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* +-----------------+
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* | type |
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* +-----------------+
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* type - uint8_t, event code, XENKBD_TYPE_???
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*
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*
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* Pointer relative movement event
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* 0 1 2 3 octet
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* +----------------+----------------+----------------+----------------+
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* | _TYPE_MOTION | reserved | 4
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* +----------------+----------------+----------------+----------------+
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* | rel_x | 8
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* +----------------+----------------+----------------+----------------+
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* | rel_y | 12
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* +----------------+----------------+----------------+----------------+
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* | rel_z | 16
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* +----------------+----------------+----------------+----------------+
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* | reserved | 20
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* +----------------+----------------+----------------+----------------+
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* |/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/|
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* +----------------+----------------+----------------+----------------+
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* | reserved | 40
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* +----------------+----------------+----------------+----------------+
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*
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* rel_x - int32_t, relative X motion
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* rel_y - int32_t, relative Y motion
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* rel_z - int32_t, relative Z motion (wheel)
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*/
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/* Pointer movement event */
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#define XENKBD_TYPE_MOTION 1
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/* Event type 2 currently not used */
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/* Key event (includes pointer buttons) */
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#define XENKBD_TYPE_KEY 3
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/*
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* Pointer position event
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* Capable backend sets feature-abs-pointer in xenstore.
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* Frontend requests ot instead of XENKBD_TYPE_MOTION by setting
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* request-abs-update in xenstore.
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*/
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#define XENKBD_TYPE_POS 4
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struct xenkbd_motion {
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uint8_t type; /* XENKBD_TYPE_MOTION */
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int32_t rel_x; /* relative X motion */
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int32_t rel_y; /* relative Y motion */
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int32_t rel_z; /* relative Z motion (wheel) */
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uint8_t type;
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int32_t rel_x;
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int32_t rel_y;
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int32_t rel_z;
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};
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/*
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* Key event (includes pointer buttons)
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* 0 1 2 3 octet
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* +----------------+----------------+----------------+----------------+
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* | _TYPE_KEY | pressed | reserved | 4
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* +----------------+----------------+----------------+----------------+
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* | keycode | 8
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* +----------------+----------------+----------------+----------------+
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* | reserved | 12
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* +----------------+----------------+----------------+----------------+
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* |/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/|
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* +----------------+----------------+----------------+----------------+
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* | reserved | 40
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* +----------------+----------------+----------------+----------------+
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*
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* pressed - uint8_t, 1 if pressed; 0 otherwise
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* keycode - uint32_t, KEY_* from linux/input.h
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*/
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struct xenkbd_key {
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uint8_t type; /* XENKBD_TYPE_KEY */
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uint8_t pressed; /* 1 if pressed; 0 otherwise */
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uint32_t keycode; /* KEY_* from linux/input.h */
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uint8_t type;
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uint8_t pressed;
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uint32_t keycode;
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};
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/*
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* Pointer absolute position event
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* 0 1 2 3 octet
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* +----------------+----------------+----------------+----------------+
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* | _TYPE_POS | reserved | 4
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* +----------------+----------------+----------------+----------------+
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* | abs_x | 8
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* +----------------+----------------+----------------+----------------+
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* | abs_y | 12
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* +----------------+----------------+----------------+----------------+
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* | rel_z | 16
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* +----------------+----------------+----------------+----------------+
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* | reserved | 20
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* +----------------+----------------+----------------+----------------+
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* |/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/|
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* +----------------+----------------+----------------+----------------+
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* | reserved | 40
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* +----------------+----------------+----------------+----------------+
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*
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* abs_x - int32_t, absolute X position (in FB pixels)
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* abs_y - int32_t, absolute Y position (in FB pixels)
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* rel_z - int32_t, relative Z motion (wheel)
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*/
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struct xenkbd_position {
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uint8_t type; /* XENKBD_TYPE_POS */
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int32_t abs_x; /* absolute X position (in FB pixels) */
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int32_t abs_y; /* absolute Y position (in FB pixels) */
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int32_t rel_z; /* relative Z motion (wheel) */
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uint8_t type;
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int32_t abs_x;
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int32_t abs_y;
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int32_t rel_z;
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};
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#define XENKBD_IN_EVENT_SIZE 40
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@ -75,12 +255,22 @@ union xenkbd_in_event {
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char pad[XENKBD_IN_EVENT_SIZE];
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};
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/* Out events (frontend -> backend) */
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/*
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*****************************************************************************
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* Frontend to backend events
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*****************************************************************************
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*
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* Out events may be sent only when requested by backend, and receipt
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* of an unknown out event is an error.
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* No out events currently defined.
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* All event packets have the same length (40 octets)
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* All event packets have common header:
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* 0 octet
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* +-----------------+
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* | type |
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* +-----------------+
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* type - uint8_t, event code
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*/
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#define XENKBD_OUT_EVENT_SIZE 40
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@ -90,7 +280,11 @@ union xenkbd_out_event {
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char pad[XENKBD_OUT_EVENT_SIZE];
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};
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/* shared page */
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/*
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*****************************************************************************
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* Shared page
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*****************************************************************************
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*/
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#define XENKBD_IN_RING_SIZE 2048
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#define XENKBD_IN_RING_LEN (XENKBD_IN_RING_SIZE / XENKBD_IN_EVENT_SIZE)
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@ -113,4 +307,4 @@ struct xenkbd_page {
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uint32_t out_cons, out_prod;
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};
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#endif
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#endif /* __XEN_PUBLIC_IO_KBDIF_H__ */
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