    /* SPDX-License-Identifier: MIT */
    /*
     * kbdif.h -- Xen virtual keyboard/mouse
     *
     * Copyright (C) 2005 Anthony Liguori <aliguori@us.ibm.com>
     * Copyright (C) 2006 Red Hat, Inc., Markus Armbruster <armbru@redhat.com>
     */

    #ifndef __XEN_PUBLIC_IO_KBDIF_H__
    #define __XEN_PUBLIC_IO_KBDIF_H__

    /*
     *****************************************************************************
     *                     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-disable-keyboard
     *      Values:         <uint>
     *
     *      If there is no need to expose a virtual keyboard device by the
     *      frontend then this must be set to 1.
     *
     * feature-disable-pointer
     *      Values:         <uint>
     *
     *      If there is no need to expose a virtual pointer device by the
     *      frontend then this must be set to 1.
     *
     * feature-abs-pointer
     *      Values:         <uint>
     *
     *      Backends, which support reporting of absolute coordinates for pointer
     *      device should set this to 1.
     *
     * feature-multi-touch
     *      Values:         <uint>
     *
     *      Backends, which support reporting of multi-touch events
     *      should set this to 1.
     *
     * feature-raw-pointer
     *      Values:        <uint>
     *
     *      Backends, which support reporting raw (unscaled) absolute coordinates
     *      for pointer devices should set this to 1. Raw (unscaled) values have
     *      a range of [0, 0x7fff].
     *
     *-----------------------  Device Instance Parameters ------------------------
     *
     * unique-id
     *      Values:         <string>
     *
     *      After device instance initialization it is assigned a unique ID,
     *      so every instance of the frontend can be identified by the backend
     *      by this ID. This can be UUID or such.
     *
     *------------------------- 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].
     *
     *----------------------- Multi-touch Device Parameters ----------------------
     *
     * multi-touch-num-contacts
     *      Values:         <uint>
     *
     *      Number of simultaneous touches reported.
     *
     * multi-touch-width
     *      Values:         <uint>
     *
     *      Width of the touch area to be used by the frontend
     *      while reporting input events, pixels, [0; UINT32_MAX].
     *
     * multi-touch-height
     *      Values:         <uint>
     *
     *      Height of the touch area 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-multi-touch
     *      Values:         <uint>
     *
     *      Request backend to report multi-touch events.
     *
     * request-raw-pointer
     *      Values:         <uint>
     *
     *      Request backend to report raw unscaled absolute pointer coordinates.
     *      This option is only valid if request-abs-pointer is also set.
     *      Raw unscaled coordinates have the range [0, 0x7fff]
     *
     *----------------------- 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.
     */

    /*
     * EVENT CODES.
     */

    #define XENKBD_TYPE_MOTION             1
    #define XENKBD_TYPE_RESERVED           2
    #define XENKBD_TYPE_KEY                3
    #define XENKBD_TYPE_POS                4
    #define XENKBD_TYPE_MTOUCH             5

    /* Multi-touch event sub-codes */

    #define XENKBD_MT_EV_DOWN              0
    #define XENKBD_MT_EV_UP                1
    #define XENKBD_MT_EV_MOTION            2
    #define XENKBD_MT_EV_SYN               3
    #define XENKBD_MT_EV_SHAPE             4
    #define XENKBD_MT_EV_ORIENT            5

    /*
     * CONSTANTS, XENSTORE FIELD AND PATH NAME STRINGS, HELPERS.
     */

    #define XENKBD_DRIVER_NAME             "vkbd"

    #define XENKBD_FIELD_FEAT_DSBL_KEYBRD  "feature-disable-keyboard"
    #define XENKBD_FIELD_FEAT_DSBL_POINTER "feature-disable-pointer"
    #define XENKBD_FIELD_FEAT_ABS_POINTER  "feature-abs-pointer"
    #define XENKBD_FIELD_FEAT_RAW_POINTER  "feature-raw-pointer"
    #define XENKBD_FIELD_FEAT_MTOUCH       "feature-multi-touch"
    #define XENKBD_FIELD_REQ_ABS_POINTER   "request-abs-pointer"
    #define XENKBD_FIELD_REQ_RAW_POINTER   "request-raw-pointer"
    #define XENKBD_FIELD_REQ_MTOUCH        "request-multi-touch"
    #define XENKBD_FIELD_RING_GREF         "page-gref"
    #define XENKBD_FIELD_EVT_CHANNEL       "event-channel"
    #define XENKBD_FIELD_WIDTH             "width"
    #define XENKBD_FIELD_HEIGHT            "height"
    #define XENKBD_FIELD_MT_WIDTH          "multi-touch-width"
    #define XENKBD_FIELD_MT_HEIGHT         "multi-touch-height"
    #define XENKBD_FIELD_MT_NUM_CONTACTS   "multi-touch-num-contacts"
    #define XENKBD_FIELD_UNIQUE_ID         "unique-id"

    /* 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)
     */

    struct xenkbd_motion
    {
        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;
        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;
        int32_t abs_x;
        int32_t abs_y;
        int32_t rel_z;
    };

    /*
     * Multi-touch event and its sub-types
     *
     * All multi-touch event packets have common header:
     *
     *         0                1                 2               3        octet
     * +----------------+----------------+----------------+----------------+
     * |  _TYPE_MTOUCH  |   event_type   |   contact_id   |    reserved    | 4
     * +----------------+----------------+----------------+----------------+
     * |                             reserved                              | 8
     * +----------------+----------------+----------------+----------------+
     *
     * event_type - unt8_t, multi-touch event sub-type, XENKBD_MT_EV_???
     * contact_id - unt8_t, ID of the contact
     *
     * Touch interactions can consist of one or more contacts.
     * For each contact, a series of events is generated, starting
     * with a down event, followed by zero or more motion events,
     * and ending with an up event. Events relating to the same
     * contact point can be identified by the ID of the sequence: contact ID.
     * Contact ID may be reused after XENKBD_MT_EV_UP event and
     * is in the [0; XENKBD_FIELD_NUM_CONTACTS - 1] range.
     *
     * For further information please refer to documentation on Wayland [1],
     * Linux [2] and Windows [3] multi-touch support.
     *
     * [1] https://cgit.freedesktop.org/wayland/wayland/tree/protocol/wayland.xml
     * [2] https://www.kernel.org/doc/Documentation/input/multi-touch-protocol.txt
     * [3] https://msdn.microsoft.com/en-us/library/jj151564(v=vs.85).aspx
     *
     *
     * Multi-touch down event - sent when a new touch is made: touch is assigned
     * a unique contact ID, sent with this and consequent events related
     * to this touch.
     *         0                1                 2               3        octet
     * +----------------+----------------+----------------+----------------+
     * |  _TYPE_MTOUCH  |   _MT_EV_DOWN  |   contact_id   |    reserved    | 4
     * +----------------+----------------+----------------+----------------+
     * |                             reserved                              | 8
     * +----------------+----------------+----------------+----------------+
     * |                               abs_x                               | 12
     * +----------------+----------------+----------------+----------------+
     * |                               abs_y                               | 16
     * +----------------+----------------+----------------+----------------+
     * |                             reserved                              | 20
     * +----------------+----------------+----------------+----------------+
     * |/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/|
     * +----------------+----------------+----------------+----------------+
     * |                             reserved                              | 40
     * +----------------+----------------+----------------+----------------+
     *
     * abs_x - int32_t, absolute X position, in pixels
     * abs_y - int32_t, absolute Y position, in pixels
     *
     * Multi-touch contact release event
     *         0                1                 2               3        octet
     * +----------------+----------------+----------------+----------------+
     * |  _TYPE_MTOUCH  |  _MT_EV_UP     |   contact_id   |    reserved    | 4
     * +----------------+----------------+----------------+----------------+
     * |                             reserved                              | 8
     * +----------------+----------------+----------------+----------------+
     * |/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/|
     * +----------------+----------------+----------------+----------------+
     * |                             reserved                              | 40
     * +----------------+----------------+----------------+----------------+
     *
     * Multi-touch motion event
     *         0                1                 2               3        octet
     * +----------------+----------------+----------------+----------------+
     * |  _TYPE_MTOUCH  |  _MT_EV_MOTION |   contact_id   |    reserved    | 4
     * +----------------+----------------+----------------+----------------+
     * |                             reserved                              | 8
     * +----------------+----------------+----------------+----------------+
     * |                               abs_x                               | 12
     * +----------------+----------------+----------------+----------------+
     * |                               abs_y                               | 16
     * +----------------+----------------+----------------+----------------+
     * |                             reserved                              | 20
     * +----------------+----------------+----------------+----------------+
     * |/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/|
     * +----------------+----------------+----------------+----------------+
     * |                             reserved                              | 40
     * +----------------+----------------+----------------+----------------+
     *
     * abs_x - int32_t, absolute X position, in pixels,
     * abs_y - int32_t, absolute Y position, in pixels,
     *
     * Multi-touch input synchronization event - shows end of a set of events
     * which logically belong together.
     *         0                1                 2               3        octet
     * +----------------+----------------+----------------+----------------+
     * |  _TYPE_MTOUCH  |  _MT_EV_SYN    |   contact_id   |    reserved    | 4
     * +----------------+----------------+----------------+----------------+
     * |                             reserved                              | 8
     * +----------------+----------------+----------------+----------------+
     * |/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/|
     * +----------------+----------------+----------------+----------------+
     * |                             reserved                              | 40
     * +----------------+----------------+----------------+----------------+
     *
     * Multi-touch shape event - touch point's shape has changed its shape.
     * Shape is approximated by an ellipse through the major and minor axis
     * lengths: major is the longer diameter of the ellipse and minor is the
     * shorter one. Center of the ellipse is reported via
     * XENKBD_MT_EV_DOWN/XENKBD_MT_EV_MOTION events.
     *         0                1                 2               3        octet
     * +----------------+----------------+----------------+----------------+
     * |  _TYPE_MTOUCH  |  _MT_EV_SHAPE  |   contact_id   |    reserved    | 4
     * +----------------+----------------+----------------+----------------+
     * |                             reserved                              | 8
     * +----------------+----------------+----------------+----------------+
     * |                               major                               | 12
     * +----------------+----------------+----------------+----------------+
     * |                               minor                               | 16
     * +----------------+----------------+----------------+----------------+
     * |                             reserved                              | 20
     * +----------------+----------------+----------------+----------------+
     * |/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/|
     * +----------------+----------------+----------------+----------------+
     * |                             reserved                              | 40
     * +----------------+----------------+----------------+----------------+
     *
     * major - unt32_t, length of the major axis, pixels
     * minor - unt32_t, length of the minor axis, pixels
     *
     * Multi-touch orientation event - touch point's shape has changed
     * its orientation: calculated as a clockwise angle between the major axis
     * of the ellipse and positive Y axis in degrees, [-180; +180].
     *         0                1                 2               3        octet
     * +----------------+----------------+----------------+----------------+
     * |  _TYPE_MTOUCH  |  _MT_EV_ORIENT |   contact_id   |    reserved    | 4
     * +----------------+----------------+----------------+----------------+
     * |                             reserved                              | 8
     * +----------------+----------------+----------------+----------------+
     * |           orientation           |            reserved             | 12
     * +----------------+----------------+----------------+----------------+
     * |                             reserved                              | 16
     * +----------------+----------------+----------------+----------------+
     * |/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/|
     * +----------------+----------------+----------------+----------------+
     * |                             reserved                              | 40
     * +----------------+----------------+----------------+----------------+
     *
     * orientation - int16_t, clockwise angle of the major axis
     */

    struct xenkbd_mtouch {
        uint8_t type;            /* XENKBD_TYPE_MTOUCH */
        uint8_t event_type;      /* XENKBD_MT_EV_??? */
        uint8_t contact_id;
        uint8_t reserved[5];     /* reserved for the future use */
        union {
            struct {
                int32_t abs_x;   /* absolute X position, pixels */
                int32_t abs_y;   /* absolute Y position, pixels */
            } pos;
            struct {
                uint32_t major;  /* length of the major axis, pixels */
                uint32_t minor;  /* length of the minor axis, pixels */
            } shape;
            int16_t orientation; /* clockwise angle of the major axis */
        } u;
    };

    #define XENKBD_IN_EVENT_SIZE 40

    union xenkbd_in_event
    {
        uint8_t type;
        struct xenkbd_motion motion;
        struct xenkbd_key key;
        struct xenkbd_position pos;
        struct xenkbd_mtouch mtouch;
        char pad[XENKBD_IN_EVENT_SIZE];
    };

    /*
     *****************************************************************************
     *                            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

    union xenkbd_out_event
    {
        uint8_t type;
        char pad[XENKBD_OUT_EVENT_SIZE];
    };

    /*
     *****************************************************************************
     *                            Shared page
     *****************************************************************************
     */

    #define XENKBD_IN_RING_SIZE 2048
    #define XENKBD_IN_RING_LEN (XENKBD_IN_RING_SIZE / XENKBD_IN_EVENT_SIZE)
    #define XENKBD_IN_RING_OFFS 1024
    #define XENKBD_IN_RING(page) \
        ((union xenkbd_in_event *)((char *)(page) + XENKBD_IN_RING_OFFS))
    #define XENKBD_IN_RING_REF(page, idx) \
        (XENKBD_IN_RING((page))[(idx) % XENKBD_IN_RING_LEN])

    #define XENKBD_OUT_RING_SIZE 1024
    #define XENKBD_OUT_RING_LEN (XENKBD_OUT_RING_SIZE / XENKBD_OUT_EVENT_SIZE)
    #define XENKBD_OUT_RING_OFFS (XENKBD_IN_RING_OFFS + XENKBD_IN_RING_SIZE)
    #define XENKBD_OUT_RING(page) \
        ((union xenkbd_out_event *)((char *)(page) + XENKBD_OUT_RING_OFFS))
    #define XENKBD_OUT_RING_REF(page, idx) \
        (XENKBD_OUT_RING((page))[(idx) % XENKBD_OUT_RING_LEN])

    struct xenkbd_page
    {
        uint32_t in_cons, in_prod;
        uint32_t out_cons, out_prod;
    };

    #endif /* __XEN_PUBLIC_IO_KBDIF_H__ */

    /*
     * Local variables:
     * mode: C
     * c-file-style: "BSD"
     * c-basic-offset: 4
     * tab-width: 4
     * indent-tabs-mode: nil
     * End:
     */