/* SPDX-License-Identifier: MIT */ /****************************************************************************** * sndif.h * * Unified sound-device I/O interface for Xen guest OSes. * * Copyright (C) 2013-2015 GlobalLogic Inc. * Copyright (C) 2016-2017 EPAM Systems Inc. * * Authors: Oleksandr Andrushchenko <[email protected]> * Oleksandr Grytsov <[email protected]> * Oleksandr Dmytryshyn <[email protected]> * Iurii Konovalenko <[email protected]> */ #ifndef __XEN_PUBLIC_IO_SNDIF_H__ #define __XEN_PUBLIC_IO_SNDIF_H__ #include "ring.h" #include "../grant_table.h" /* ****************************************************************************** * Protocol version ****************************************************************************** */ #define XENSND_PROTOCOL_VERSION … /* ****************************************************************************** * Feature and Parameter Negotiation ****************************************************************************** * * Front->back notifications: when enqueuing a new request, sending a * notification can be made conditional on xensnd_req (i.e., the generic * hold-off mechanism provided by the ring macros). Backends must set * xensnd_req appropriately (e.g., using RING_FINAL_CHECK_FOR_REQUESTS()). * * Back->front notifications: when enqueuing a new response, sending a * notification can be made conditional on xensnd_resp (i.e., the generic * hold-off mechanism provided by the ring macros). Frontends must set * xensnd_resp appropriately (e.g., using RING_FINAL_CHECK_FOR_RESPONSES()). * * The two halves of a para-virtual sound card 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 the 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. * ****************************************************************************** * Example configuration ****************************************************************************** * * Note: depending on the use-case backend can expose more sound cards and * PCM devices/streams than the underlying HW physically has by employing * SW mixers, configuring virtual sound streams, channels etc. * * This is an example of backend and frontend configuration: * *--------------------------------- Backend ----------------------------------- * * /local/domain/0/backend/vsnd/1/0/frontend-id = "1" * /local/domain/0/backend/vsnd/1/0/frontend = "/local/domain/1/device/vsnd/0" * /local/domain/0/backend/vsnd/1/0/state = "4" * /local/domain/0/backend/vsnd/1/0/versions = "1,2" * *--------------------------------- Frontend ---------------------------------- * * /local/domain/1/device/vsnd/0/backend-id = "0" * /local/domain/1/device/vsnd/0/backend = "/local/domain/0/backend/vsnd/1/0" * /local/domain/1/device/vsnd/0/state = "4" * /local/domain/1/device/vsnd/0/version = "1" * *----------------------------- Card configuration ---------------------------- * * /local/domain/1/device/vsnd/0/short-name = "Card short name" * /local/domain/1/device/vsnd/0/long-name = "Card long name" * /local/domain/1/device/vsnd/0/sample-rates = "8000,32000,44100,48000,96000" * /local/domain/1/device/vsnd/0/sample-formats = "s8,u8,s16_le,s16_be" * /local/domain/1/device/vsnd/0/buffer-size = "262144" * *------------------------------- PCM device 0 -------------------------------- * * /local/domain/1/device/vsnd/0/0/name = "General analog" * /local/domain/1/device/vsnd/0/0/channels-max = "5" * *----------------------------- Stream 0, playback ---------------------------- * * /local/domain/1/device/vsnd/0/0/0/type = "p" * /local/domain/1/device/vsnd/0/0/0/sample-formats = "s8,u8" * /local/domain/1/device/vsnd/0/0/0/unique-id = "0" * * /local/domain/1/device/vsnd/0/0/0/ring-ref = "386" * /local/domain/1/device/vsnd/0/0/0/event-channel = "15" * /local/domain/1/device/vsnd/0/0/0/evt-ring-ref = "1386" * /local/domain/1/device/vsnd/0/0/0/evt-event-channel = "215" * *------------------------------ Stream 1, capture ---------------------------- * * /local/domain/1/device/vsnd/0/0/1/type = "c" * /local/domain/1/device/vsnd/0/0/1/channels-max = "2" * /local/domain/1/device/vsnd/0/0/1/unique-id = "1" * * /local/domain/1/device/vsnd/0/0/1/ring-ref = "384" * /local/domain/1/device/vsnd/0/0/1/event-channel = "13" * /local/domain/1/device/vsnd/0/0/1/evt-ring-ref = "1384" * /local/domain/1/device/vsnd/0/0/1/evt-event-channel = "213" * *------------------------------- PCM device 1 -------------------------------- * * /local/domain/1/device/vsnd/0/1/name = "HDMI-0" * /local/domain/1/device/vsnd/0/1/sample-rates = "8000,32000,44100" * *------------------------------ Stream 0, capture ---------------------------- * * /local/domain/1/device/vsnd/0/1/0/type = "c" * /local/domain/1/device/vsnd/0/1/0/unique-id = "2" * * /local/domain/1/device/vsnd/0/1/0/ring-ref = "387" * /local/domain/1/device/vsnd/0/1/0/event-channel = "151" * /local/domain/1/device/vsnd/0/1/0/evt-ring-ref = "1387" * /local/domain/1/device/vsnd/0/1/0/evt-event-channel = "351" * *------------------------------- PCM device 2 -------------------------------- * * /local/domain/1/device/vsnd/0/2/name = "SPDIF" * *----------------------------- Stream 0, playback ---------------------------- * * /local/domain/1/device/vsnd/0/2/0/type = "p" * /local/domain/1/device/vsnd/0/2/0/unique-id = "3" * * /local/domain/1/device/vsnd/0/2/0/ring-ref = "389" * /local/domain/1/device/vsnd/0/2/0/event-channel = "152" * /local/domain/1/device/vsnd/0/2/0/evt-ring-ref = "1389" * /local/domain/1/device/vsnd/0/2/0/evt-event-channel = "452" * ****************************************************************************** * Backend XenBus Nodes ****************************************************************************** * *----------------------------- Protocol version ------------------------------ * * versions * Values: <string> * * List of XENSND_LIST_SEPARATOR separated protocol versions supported * by the backend. For example "1,2,3". * ****************************************************************************** * Frontend XenBus Nodes ****************************************************************************** * *-------------------------------- Addressing --------------------------------- * * dom-id * Values: <uint16_t> * * Domain identifier. * * dev-id * Values: <uint16_t> * * Device identifier. * * pcm-dev-idx * Values: <uint8_t> * * Zero based contigous index of the PCM device. * * stream-idx * Values: <uint8_t> * * Zero based contigous index of the stream of the PCM device. * * The following pattern is used for addressing: * /local/domain/<dom-id>/device/vsnd/<dev-id>/<pcm-dev-idx>/<stream-idx>/... * *----------------------------- Protocol version ------------------------------ * * version * Values: <string> * * Protocol version, chosen among the ones supported by the backend. * *------------------------------- PCM settings -------------------------------- * * Every virtualized sound frontend has a set of PCM devices and streams, each * could be individually configured. Part of the PCM configuration can be * defined at higher level of the hierarchy and be fully or partially re-used * by the underlying layers. These configuration values are: * o number of channels (min/max) * o supported sample rates * o supported sample formats. * E.g. one can define these values for the whole card, device or stream. * Every underlying layer in turn can re-define some or all of them to better * fit its needs. For example, card may define number of channels to be * in [1; 8] range, and some particular stream may be limited to [1; 2] only. * The rule is that the underlying layer must be a subset of the upper layer * range. * * channels-min * Values: <uint8_t> * * The minimum amount of channels that is supported, [1; channels-max]. * Optional, if not set or omitted a value of 1 is used. * * channels-max * Values: <uint8_t> * * The maximum amount of channels that is supported. * Must be at least <channels-min>. * * sample-rates * Values: <list of uint32_t> * * List of supported sample rates separated by XENSND_LIST_SEPARATOR. * Sample rates are expressed as a list of decimal values w/o any * ordering requirement. * * sample-formats * Values: <list of XENSND_PCM_FORMAT_XXX_STR> * * List of supported sample formats separated by XENSND_LIST_SEPARATOR. * Items must not exceed XENSND_SAMPLE_FORMAT_MAX_LEN length. * * buffer-size * Values: <uint32_t> * * The maximum size in octets of the buffer to allocate per stream. * *----------------------- Virtual sound card settings ------------------------- * short-name * Values: <char[32]> * * Short name of the virtual sound card. Optional. * * long-name * Values: <char[80]> * * Long name of the virtual sound card. Optional. * *----------------------------- Device settings ------------------------------- * name * Values: <char[80]> * * Name of the sound device within the virtual sound card. Optional. * *----------------------------- Stream settings ------------------------------- * * type * Values: "p", "c" * * Stream type: "p" - playback stream, "c" - capture stream * * If both capture and playback are needed then two streams need to be * defined under the same device. * * unique-id * Values: <string> * * After stream initialization it is assigned a unique ID, so every * stream of the frontend can be identified by the backend by this ID. * This can be UUID or such. * *-------------------- Stream Request Transport Parameters -------------------- * * event-channel * Values: <uint32_t> * * The identifier of the Xen event channel used to signal activity * in the ring buffer. * * ring-ref * Values: <uint32_t> * * The Xen grant reference granting permission for the backend to map * a sole page in a single page sized ring buffer. * *--------------------- Stream Event Transport Parameters --------------------- * * This communication path is used to deliver asynchronous events from backend * to frontend, set up per stream. * * evt-event-channel * Values: <uint32_t> * * The identifier of the Xen event channel used to signal activity * in the ring buffer. * * evt-ring-ref * Values: <uint32_t> * * The Xen grant reference granting permission for the backend to map * a sole page in a single page sized ring buffer. * ****************************************************************************** * STATE DIAGRAMS ****************************************************************************** * * Tool stack creates front and back state nodes with initial state * XenbusStateInitialising. * Tool stack creates and sets up frontend sound configuration nodes per domain. * * Front Back * ================================= ===================================== * XenbusStateInitialising XenbusStateInitialising * o Query backend device identification * data. * o Open and validate backend device. * | * | * V * XenbusStateInitWait * * o Query frontend configuration * o Allocate and initialize * event channels per configured * playback/capture stream. * o Publish transport parameters * that will be in effect during * this connection. * | * | * V * XenbusStateInitialised * * o Query frontend transport parameters. * o Connect to the event channels. * | * | * V * XenbusStateConnected * * o Create and initialize OS * virtual sound device instances * as per configuration. * | * | * V * XenbusStateConnected * * XenbusStateUnknown * XenbusStateClosed * XenbusStateClosing * o Remove virtual sound device * o Remove event channels * | * | * V * XenbusStateClosed * *------------------------------- Recovery flow ------------------------------- * * In case of frontend unrecoverable errors backend handles that as * if frontend goes into the XenbusStateClosed state. * * In case of backend unrecoverable errors frontend tries removing * the virtualized device. If this is possible at the moment of error, * then frontend goes into the XenbusStateInitialising state and is ready for * new connection with backend. If the virtualized device is still in use and * cannot be removed, then frontend goes into the XenbusStateReconfiguring state * until either the virtualized device removed or backend initiates a new * connection. On the virtualized device removal frontend goes into the * XenbusStateInitialising state. * * Note on XenbusStateReconfiguring state of the frontend: if backend has * unrecoverable errors then frontend cannot send requests to the backend * and thus cannot provide functionality of the virtualized device anymore. * After backend is back to normal the virtualized device may still hold some * state: configuration in use, allocated buffers, client application state etc. * So, in most cases, this will require frontend to implement complex recovery * reconnect logic. Instead, by going into XenbusStateReconfiguring state, * frontend will make sure no new clients of the virtualized device are * accepted, allow existing client(s) to exit gracefully by signaling error * state etc. * Once all the clients are gone frontend can reinitialize the virtualized * device and get into XenbusStateInitialising state again signaling the * backend that a new connection can be made. * * There are multiple conditions possible under which frontend will go from * XenbusStateReconfiguring into XenbusStateInitialising, some of them are OS * specific. For example: * 1. The underlying OS framework may provide callbacks to signal that the last * client of the virtualized device has gone and the device can be removed * 2. Frontend can schedule a deferred work (timer/tasklet/workqueue) * to periodically check if this is the right time to re-try removal of * the virtualized device. * 3. By any other means. * ****************************************************************************** * PCM FORMATS ****************************************************************************** * * XENSND_PCM_FORMAT_<format>[_<endian>] * * format: <S/U/F><bits> or <name> * S - signed, U - unsigned, F - float * bits - 8, 16, 24, 32 * name - MU_LAW, GSM, etc. * * endian: <LE/BE>, may be absent * LE - Little endian, BE - Big endian */ #define XENSND_PCM_FORMAT_S8 … #define XENSND_PCM_FORMAT_U8 … #define XENSND_PCM_FORMAT_S16_LE … #define XENSND_PCM_FORMAT_S16_BE … #define XENSND_PCM_FORMAT_U16_LE … #define XENSND_PCM_FORMAT_U16_BE … #define XENSND_PCM_FORMAT_S24_LE … #define XENSND_PCM_FORMAT_S24_BE … #define XENSND_PCM_FORMAT_U24_LE … #define XENSND_PCM_FORMAT_U24_BE … #define XENSND_PCM_FORMAT_S32_LE … #define XENSND_PCM_FORMAT_S32_BE … #define XENSND_PCM_FORMAT_U32_LE … #define XENSND_PCM_FORMAT_U32_BE … #define XENSND_PCM_FORMAT_F32_LE … #define XENSND_PCM_FORMAT_F32_BE … #define XENSND_PCM_FORMAT_F64_LE … #define XENSND_PCM_FORMAT_F64_BE … #define XENSND_PCM_FORMAT_IEC958_SUBFRAME_LE … #define XENSND_PCM_FORMAT_IEC958_SUBFRAME_BE … #define XENSND_PCM_FORMAT_MU_LAW … #define XENSND_PCM_FORMAT_A_LAW … #define XENSND_PCM_FORMAT_IMA_ADPCM … #define XENSND_PCM_FORMAT_MPEG … #define XENSND_PCM_FORMAT_GSM … /* ****************************************************************************** * REQUEST CODES ****************************************************************************** */ #define XENSND_OP_OPEN … #define XENSND_OP_CLOSE … #define XENSND_OP_READ … #define XENSND_OP_WRITE … #define XENSND_OP_SET_VOLUME … #define XENSND_OP_GET_VOLUME … #define XENSND_OP_MUTE … #define XENSND_OP_UNMUTE … #define XENSND_OP_TRIGGER … #define XENSND_OP_HW_PARAM_QUERY … #define XENSND_OP_TRIGGER_START … #define XENSND_OP_TRIGGER_PAUSE … #define XENSND_OP_TRIGGER_STOP … #define XENSND_OP_TRIGGER_RESUME … /* ****************************************************************************** * EVENT CODES ****************************************************************************** */ #define XENSND_EVT_CUR_POS … /* ****************************************************************************** * XENSTORE FIELD AND PATH NAME STRINGS, HELPERS ****************************************************************************** */ #define XENSND_DRIVER_NAME … #define XENSND_LIST_SEPARATOR … /* Field names */ #define XENSND_FIELD_BE_VERSIONS … #define XENSND_FIELD_FE_VERSION … #define XENSND_FIELD_VCARD_SHORT_NAME … #define XENSND_FIELD_VCARD_LONG_NAME … #define XENSND_FIELD_RING_REF … #define XENSND_FIELD_EVT_CHNL … #define XENSND_FIELD_EVT_RING_REF … #define XENSND_FIELD_EVT_EVT_CHNL … #define XENSND_FIELD_DEVICE_NAME … #define XENSND_FIELD_TYPE … #define XENSND_FIELD_STREAM_UNIQUE_ID … #define XENSND_FIELD_CHANNELS_MIN … #define XENSND_FIELD_CHANNELS_MAX … #define XENSND_FIELD_SAMPLE_RATES … #define XENSND_FIELD_SAMPLE_FORMATS … #define XENSND_FIELD_BUFFER_SIZE … /* Stream type field values. */ #define XENSND_STREAM_TYPE_PLAYBACK … #define XENSND_STREAM_TYPE_CAPTURE … /* Sample rate max string length */ #define XENSND_SAMPLE_RATE_MAX_LEN … /* Sample format field values */ #define XENSND_SAMPLE_FORMAT_MAX_LEN … #define XENSND_PCM_FORMAT_S8_STR … #define XENSND_PCM_FORMAT_U8_STR … #define XENSND_PCM_FORMAT_S16_LE_STR … #define XENSND_PCM_FORMAT_S16_BE_STR … #define XENSND_PCM_FORMAT_U16_LE_STR … #define XENSND_PCM_FORMAT_U16_BE_STR … #define XENSND_PCM_FORMAT_S24_LE_STR … #define XENSND_PCM_FORMAT_S24_BE_STR … #define XENSND_PCM_FORMAT_U24_LE_STR … #define XENSND_PCM_FORMAT_U24_BE_STR … #define XENSND_PCM_FORMAT_S32_LE_STR … #define XENSND_PCM_FORMAT_S32_BE_STR … #define XENSND_PCM_FORMAT_U32_LE_STR … #define XENSND_PCM_FORMAT_U32_BE_STR … #define XENSND_PCM_FORMAT_F32_LE_STR … #define XENSND_PCM_FORMAT_F32_BE_STR … #define XENSND_PCM_FORMAT_F64_LE_STR … #define XENSND_PCM_FORMAT_F64_BE_STR … #define XENSND_PCM_FORMAT_IEC958_SUBFRAME_LE_STR … #define XENSND_PCM_FORMAT_IEC958_SUBFRAME_BE_STR … #define XENSND_PCM_FORMAT_MU_LAW_STR … #define XENSND_PCM_FORMAT_A_LAW_STR … #define XENSND_PCM_FORMAT_IMA_ADPCM_STR … #define XENSND_PCM_FORMAT_MPEG_STR … #define XENSND_PCM_FORMAT_GSM_STR … /* ****************************************************************************** * STATUS RETURN CODES ****************************************************************************** * * Status return code is zero on success and -XEN_EXX on failure. * ****************************************************************************** * Assumptions ****************************************************************************** * o usage of grant reference 0 as invalid grant reference: * grant reference 0 is valid, but never exposed to a PV driver, * because of the fact it is already in use/reserved by the PV console. * o all references in this document to page sizes must be treated * as pages of size XEN_PAGE_SIZE unless otherwise noted. * ****************************************************************************** * Description of the protocol between frontend and backend driver ****************************************************************************** * * The two halves of a Para-virtual sound driver communicate with * each other using shared pages and event channels. * Shared page contains a ring with request/response packets. * * Packets, used for input/output operations, e.g. read/write, set/get volume, * etc., provide offset/length fields in order to allow asynchronous protocol * operation with buffer space sharing: part of the buffer allocated at * XENSND_OP_OPEN can be used for audio samples and part, for example, * for volume control. * * All reserved fields in the structures below must be 0. * *---------------------------------- Requests --------------------------------- * * All request packets have the same length (64 octets) * All request packets have common header: * 0 1 2 3 octet * +----------------+----------------+----------------+----------------+ * | id | operation | reserved | 4 * +----------------+----------------+----------------+----------------+ * | reserved | 8 * +----------------+----------------+----------------+----------------+ * id - uint16_t, private guest value, echoed in response * operation - uint8_t, operation code, XENSND_OP_??? * * For all packets which use offset and length: * offset - uint32_t, read or write data offset within the shared buffer, * passed with XENSND_OP_OPEN request, octets, * [0; XENSND_OP_OPEN.buffer_sz - 1]. * length - uint32_t, read or write data length, octets * * Request open - open a PCM stream for playback or capture: * * 0 1 2 3 octet * +----------------+----------------+----------------+----------------+ * | id | XENSND_OP_OPEN | reserved | 4 * +----------------+----------------+----------------+----------------+ * | reserved | 8 * +----------------+----------------+----------------+----------------+ * | pcm_rate | 12 * +----------------+----------------+----------------+----------------+ * | pcm_format | pcm_channels | reserved | 16 * +----------------+----------------+----------------+----------------+ * | buffer_sz | 20 * +----------------+----------------+----------------+----------------+ * | gref_directory | 24 * +----------------+----------------+----------------+----------------+ * | period_sz | 28 * +----------------+----------------+----------------+----------------+ * | reserved | 32 * +----------------+----------------+----------------+----------------+ * |/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/| * +----------------+----------------+----------------+----------------+ * | reserved | 64 * +----------------+----------------+----------------+----------------+ * * pcm_rate - uint32_t, stream data rate, Hz * pcm_format - uint8_t, XENSND_PCM_FORMAT_XXX value * pcm_channels - uint8_t, number of channels of this stream, * [channels-min; channels-max] * buffer_sz - uint32_t, buffer size to be allocated, octets * period_sz - uint32_t, event period size, octets * This is the requested value of the period at which frontend would * like to receive XENSND_EVT_CUR_POS notifications from the backend when * stream position advances during playback/capture. * It shows how many octets are expected to be played/captured before * sending such an event. * If set to 0 no XENSND_EVT_CUR_POS events are sent by the backend. * * gref_directory - grant_ref_t, a reference to the first shared page * describing shared buffer references. At least one page exists. If shared * buffer size (buffer_sz) exceeds what can be addressed by this single page, * then reference to the next page must be supplied (see gref_dir_next_page * below) */ struct xensnd_open_req { … }; /* * Shared page for XENSND_OP_OPEN buffer descriptor (gref_directory in the * request) employs a list of pages, describing all pages of the shared data * buffer: * 0 1 2 3 octet * +----------------+----------------+----------------+----------------+ * | gref_dir_next_page | 4 * +----------------+----------------+----------------+----------------+ * | gref[0] | 8 * +----------------+----------------+----------------+----------------+ * |/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/| * +----------------+----------------+----------------+----------------+ * | gref[i] | i*4+8 * +----------------+----------------+----------------+----------------+ * |/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/| * +----------------+----------------+----------------+----------------+ * | gref[N - 1] | N*4+8 * +----------------+----------------+----------------+----------------+ * * gref_dir_next_page - grant_ref_t, reference to the next page describing * page directory. Must be 0 if there are no more pages in the list. * gref[i] - grant_ref_t, reference to a shared page of the buffer * allocated at XENSND_OP_OPEN * * Number of grant_ref_t entries in the whole page directory is not * passed, but instead can be calculated as: * num_grefs_total = (XENSND_OP_OPEN.buffer_sz + XEN_PAGE_SIZE - 1) / * XEN_PAGE_SIZE */ struct xensnd_page_directory { … }; /* * Request close - close an opened pcm stream: * 0 1 2 3 octet * +----------------+----------------+----------------+----------------+ * | id | XENSND_OP_CLOSE| reserved | 4 * +----------------+----------------+----------------+----------------+ * | reserved | 8 * +----------------+----------------+----------------+----------------+ * |/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/| * +----------------+----------------+----------------+----------------+ * | reserved | 64 * +----------------+----------------+----------------+----------------+ * * Request read/write - used for read (for capture) or write (for playback): * 0 1 2 3 octet * +----------------+----------------+----------------+----------------+ * | id | operation | reserved | 4 * +----------------+----------------+----------------+----------------+ * | reserved | 8 * +----------------+----------------+----------------+----------------+ * | offset | 12 * +----------------+----------------+----------------+----------------+ * | length | 16 * +----------------+----------------+----------------+----------------+ * | reserved | 20 * +----------------+----------------+----------------+----------------+ * |/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/| * +----------------+----------------+----------------+----------------+ * | reserved | 64 * +----------------+----------------+----------------+----------------+ * * operation - XENSND_OP_READ for read or XENSND_OP_WRITE for write */ struct xensnd_rw_req { … }; /* * Request set/get volume - set/get channels' volume of the stream given: * 0 1 2 3 octet * +----------------+----------------+----------------+----------------+ * | id | operation | reserved | 4 * +----------------+----------------+----------------+----------------+ * | reserved | 8 * +----------------+----------------+----------------+----------------+ * | offset | 12 * +----------------+----------------+----------------+----------------+ * | length | 16 * +----------------+----------------+----------------+----------------+ * | reserved | 20 * +----------------+----------------+----------------+----------------+ * |/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/| * +----------------+----------------+----------------+----------------+ * | reserved | 64 * +----------------+----------------+----------------+----------------+ * * operation - XENSND_OP_SET_VOLUME for volume set * or XENSND_OP_GET_VOLUME for volume get * Buffer passed with XENSND_OP_OPEN is used to exchange volume * values: * * 0 1 2 3 octet * +----------------+----------------+----------------+----------------+ * | channel[0] | 4 * +----------------+----------------+----------------+----------------+ * |/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/| * +----------------+----------------+----------------+----------------+ * | channel[i] | i*4 * +----------------+----------------+----------------+----------------+ * |/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/| * +----------------+----------------+----------------+----------------+ * | channel[N - 1] | (N-1)*4 * +----------------+----------------+----------------+----------------+ * * N = XENSND_OP_OPEN.pcm_channels * i - uint8_t, index of a channel * channel[i] - sint32_t, volume of i-th channel * Volume is expressed as a signed value in steps of 0.001 dB, * while 0 being 0 dB. * * Request mute/unmute - mute/unmute stream: * 0 1 2 3 octet * +----------------+----------------+----------------+----------------+ * | id | operation | reserved | 4 * +----------------+----------------+----------------+----------------+ * | reserved | 8 * +----------------+----------------+----------------+----------------+ * | offset | 12 * +----------------+----------------+----------------+----------------+ * | length | 16 * +----------------+----------------+----------------+----------------+ * | reserved | 20 * +----------------+----------------+----------------+----------------+ * |/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/| * +----------------+----------------+----------------+----------------+ * | reserved | 64 * +----------------+----------------+----------------+----------------+ * * operation - XENSND_OP_MUTE for mute or XENSND_OP_UNMUTE for unmute * Buffer passed with XENSND_OP_OPEN is used to exchange mute/unmute * values: * * 0 octet * +----------------+----------------+----------------+----------------+ * | channel[0] | 4 * +----------------+----------------+----------------+----------------+ * +/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/| * +----------------+----------------+----------------+----------------+ * | channel[i] | i*4 * +----------------+----------------+----------------+----------------+ * +/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/| * +----------------+----------------+----------------+----------------+ * | channel[N - 1] | (N-1)*4 * +----------------+----------------+----------------+----------------+ * * N = XENSND_OP_OPEN.pcm_channels * i - uint8_t, index of a channel * channel[i] - uint8_t, non-zero if i-th channel needs to be muted/unmuted * *------------------------------------ N.B. ----------------------------------- * * The 'struct xensnd_rw_req' is also used for XENSND_OP_SET_VOLUME, * XENSND_OP_GET_VOLUME, XENSND_OP_MUTE, XENSND_OP_UNMUTE. * * Request stream running state change - trigger PCM stream running state * to start, stop, pause or resume: * * 0 1 2 3 octet * +----------------+----------------+----------------+----------------+ * | id | _OP_TRIGGER | reserved | 4 * +----------------+----------------+----------------+----------------+ * | reserved | 8 * +----------------+----------------+----------------+----------------+ * | type | reserved | 12 * +----------------+----------------+----------------+----------------+ * | reserved | 16 * +----------------+----------------+----------------+----------------+ * |/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/| * +----------------+----------------+----------------+----------------+ * | reserved | 64 * +----------------+----------------+----------------+----------------+ * * type - uint8_t, XENSND_OP_TRIGGER_XXX value */ struct xensnd_trigger_req { … }; /* * Request stream parameter ranges: request intervals and * masks of supported ranges for stream configuration values. * * Sound device configuration for a particular stream is a limited subset * of the multidimensional configuration available on XenStore, e.g. * once the frame rate has been selected there is a limited supported range * for sample rates becomes available (which might be the same set configured * on XenStore or less). For example, selecting 96kHz sample rate may limit * number of channels available for such configuration from 4 to 2, etc. * Thus, each call to XENSND_OP_HW_PARAM_QUERY may reduce configuration * space making it possible to iteratively get the final stream configuration, * used in XENSND_OP_OPEN request. * * See response format for this request. * * 0 1 2 3 octet * +----------------+----------------+----------------+----------------+ * | id | _HW_PARAM_QUERY| reserved | 4 * +----------------+----------------+----------------+----------------+ * | reserved | 8 * +----------------+----------------+----------------+----------------+ * | formats mask low 32-bit | 12 * +----------------+----------------+----------------+----------------+ * | formats mask high 32-bit | 16 * +----------------+----------------+----------------+----------------+ * | min rate | 20 * +----------------+----------------+----------------+----------------+ * | max rate | 24 * +----------------+----------------+----------------+----------------+ * | min channels | 28 * +----------------+----------------+----------------+----------------+ * | max channels | 32 * +----------------+----------------+----------------+----------------+ * | min buffer frames | 36 * +----------------+----------------+----------------+----------------+ * | max buffer frames | 40 * +----------------+----------------+----------------+----------------+ * | min period frames | 44 * +----------------+----------------+----------------+----------------+ * | max period frames | 48 * +----------------+----------------+----------------+----------------+ * | reserved | 52 * +----------------+----------------+----------------+----------------+ * |/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/| * +----------------+----------------+----------------+----------------+ * | reserved | 64 * +----------------+----------------+----------------+----------------+ * * formats - uint64_t, bit mask representing values of the parameter * made as bitwise OR of (1 << XENSND_PCM_FORMAT_XXX) values * * For interval parameters: * min - uint32_t, minimum value of the parameter * max - uint32_t, maximum value of the parameter * * Frame is defined as a product of the number of channels by the * number of octets per one sample. */ struct xensnd_query_hw_param { … }; /* *---------------------------------- Responses -------------------------------- * * All response packets have the same length (64 octets) * * All response packets have common header: * 0 1 2 3 octet * +----------------+----------------+----------------+----------------+ * | id | operation | reserved | 4 * +----------------+----------------+----------------+----------------+ * | status | 8 * +----------------+----------------+----------------+----------------+ * * id - uint16_t, copied from the request * operation - uint8_t, XENSND_OP_* - copied from request * status - int32_t, response status, zero on success and -XEN_EXX on failure * * * HW parameter query response - response for XENSND_OP_HW_PARAM_QUERY: * 0 1 2 3 octet * +----------------+----------------+----------------+----------------+ * | id | operation | reserved | 4 * +----------------+----------------+----------------+----------------+ * | status | 8 * +----------------+----------------+----------------+----------------+ * | formats mask low 32-bit | 12 * +----------------+----------------+----------------+----------------+ * | formats mask high 32-bit | 16 * +----------------+----------------+----------------+----------------+ * | min rate | 20 * +----------------+----------------+----------------+----------------+ * | max rate | 24 * +----------------+----------------+----------------+----------------+ * | min channels | 28 * +----------------+----------------+----------------+----------------+ * | max channels | 32 * +----------------+----------------+----------------+----------------+ * | min buffer frames | 36 * +----------------+----------------+----------------+----------------+ * | max buffer frames | 40 * +----------------+----------------+----------------+----------------+ * | min period frames | 44 * +----------------+----------------+----------------+----------------+ * | max period frames | 48 * +----------------+----------------+----------------+----------------+ * | reserved | 52 * +----------------+----------------+----------------+----------------+ * |/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/| * +----------------+----------------+----------------+----------------+ * | reserved | 64 * +----------------+----------------+----------------+----------------+ * * Meaning of the values in this response is the same as for * XENSND_OP_HW_PARAM_QUERY request. */ /* *----------------------------------- Events ---------------------------------- * * Events are sent via shared page allocated by the front and propagated by * evt-event-channel/evt-ring-ref XenStore entries * All event packets have the same length (64 octets) * All event packets have common header: * 0 1 2 3 octet * +----------------+----------------+----------------+----------------+ * | id | type | reserved | 4 * +----------------+----------------+----------------+----------------+ * | reserved | 8 * +----------------+----------------+----------------+----------------+ * * id - uint16_t, event id, may be used by front * type - uint8_t, type of the event * * * Current stream position - event from back to front when stream's * playback/capture position has advanced: * 0 1 2 3 octet * +----------------+----------------+----------------+----------------+ * | id | _EVT_CUR_POS | reserved | 4 * +----------------+----------------+----------------+----------------+ * | reserved | 8 * +----------------+----------------+----------------+----------------+ * | position low 32-bit | 12 * +----------------+----------------+----------------+----------------+ * | position high 32-bit | 16 * +----------------+----------------+----------------+----------------+ * | reserved | 20 * +----------------+----------------+----------------+----------------+ * |/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/| * +----------------+----------------+----------------+----------------+ * | reserved | 64 * +----------------+----------------+----------------+----------------+ * * position - current value of stream's playback/capture position, octets * */ struct xensnd_cur_pos_evt { … }; struct xensnd_req { … }; struct xensnd_resp { … }; struct xensnd_evt { … }; DEFINE_RING_TYPES(xen_sndif, struct xensnd_req, struct xensnd_resp); /* ****************************************************************************** * Back to front events delivery ****************************************************************************** * In order to deliver asynchronous events from back to front a shared page is * allocated by front and its granted reference propagated to back via * XenStore entries (evt-ring-ref/evt-event-channel). * This page has a common header used by both front and back to synchronize * access and control event's ring buffer, while back being a producer of the * events and front being a consumer. The rest of the page after the header * is used for event packets. * * Upon reception of an event(s) front may confirm its reception * for either each event, group of events or none. */ struct xensnd_event_page { … }; #define XENSND_EVENT_PAGE_SIZE … #define XENSND_IN_RING_OFFS … #define XENSND_IN_RING_SIZE … #define XENSND_IN_RING_LEN … #define XENSND_IN_RING(page) … #define XENSND_IN_RING_REF(page, idx) … #endif /* __XEN_PUBLIC_IO_SNDIF_H__ */
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