From: Oleksandr Andrushchenko Date: Mon, 10 Apr 2017 06:25:26 +0000 (+0300) Subject: xen/kbdif: update protocol description X-Git-Tag: v4.12-rc1~16^2~31 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=8ec9dd0e69cfaab05649ed7ab3838eb4eea96081;p=platform%2Fkernel%2Flinux-exynos.git xen/kbdif: update protocol description The patch clarifies the protocol that is used by the PV keyboard drivers. Signed-off-by: Oleksandr Andrushchenko Acked-by: Juergen Gross Signed-off-by: Juergen Gross --- diff --git a/include/xen/interface/io/kbdif.h b/include/xen/interface/io/kbdif.h index 8066c78..7adfb15 100644 --- a/include/xen/interface/io/kbdif.h +++ b/include/xen/interface/io/kbdif.h @@ -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: + * + * Backends, which support reporting of absolute coordinates for pointer + * device should set this to 1. + * + *------------------------- Pointer Device Parameters ------------------------ + * + * width + * Values: + * + * Maximum X coordinate (width) to be used by the frontend + * while reporting input events, pixels, [0; UINT32_MAX]. + * + * height + * Values: + * + * 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: + * + * Request backend to report absolute pointer coordinates + * (XENKBD_TYPE_POS) instead of relative ones (XENKBD_TYPE_MOTION). + * + *----------------------- Request Transport Parameters ----------------------- + * + * event-channel + * Values: + * + * The identifier of the Xen event channel used to signal activity + * in the ring buffer. + * + * page-gref + * Values: + * + * 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: + * + * 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_KEY 3 +#define XENKBD_TYPE_MOTION 1 +#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__ */