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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Embedded-pv-devel] [PATCH v6] sndif: add ABI for Para-virtual sound
On Thu, Jan 29, 2015 at 1:01 PM, Oleksandr Dmytryshyn
<oleksandr.dmytryshyn@xxxxxxxxxxxxxxx> wrote:
>
> This is ABI for the two halves of a Para-virtual
> sound driver to communicate with each to other.
>
> Signed-off-by: Oleksandr Dmytryshyn <oleksandr.dmytryshyn@xxxxxxxxxxxxxxx>
> Signed-off-by: Iurii Konovalenko <iurii.konovalenko@xxxxxxxxxxxxxxx>
> ---
> Changes since v1:
> * removed __attribute__((__packed__)) from all structures definitions
>
> Changes since v2:
> * removed all C structures
> * added protocol description between frontend and backend drivers
>
> Changes since v3:
> * fixed some typos
> * renamed XENSND_PCM_FORMAT_FLOAT_** to XENSND_PCM_FORMAT_F32_**
> * renamed XENSND_PCM_FORMAT_FLOAT64_** to XENSND_PCM_FORMAT_F64_**
> * added 'id' field to the request and response packets
> * renamed 'stream_id' to 'stream' in the packets description
> * renamed 'pcm_data_rate' to 'pcm_rate' in the packets description
> * renamed 'pcm_stream_type' to 'pcm_type' in the packets description
> * removed 'stream_id' field from the response packets
>
> Changes since v4:
> * renamed 'stream_id' back to the to 'stream' in the packets description
> * moved 'id' field to the upper position in the response packets
>
> Changes since v5:
> * Slightly reworked request/response packets
> * Size of the request/response packet is changed to the 64 bytes
> * Now parameters for the XENSND_OP_SET_VOLUME/XENSND_OP_GET_VOLUME are
> passed via shared page
> * Added parameters for the XenBus nodes (now each stream can be mapped
> to the defined sound device in the backend using those parameters)
> * Added XenBus state diagrams description
>
> xen/include/public/io/sndif.h | 421
> ++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 421 insertions(+)
> create mode 100644 xen/include/public/io/sndif.h
>
> diff --git a/xen/include/public/io/sndif.h b/xen/include/public/io/sndif.h
> new file mode 100644
> index 0000000..f2e080b
> --- /dev/null
> +++ b/xen/include/public/io/sndif.h
> @@ -0,0 +1,421 @@
> +/******************************************************************************
> + * sndif.h
> + *
> + * Unified sound-device I/O interface for Xen guest OSes.
> + *
> + * Permission is hereby granted, free of charge, to any person obtaining a
> copy
> + * of this software and associated documentation files (the "Software"), to
> + * deal in the Software without restriction, including without limitation the
> + * rights to use, copy, modify, merge, publish, distribute, sublicense,
> and/or
> + * sell copies of the Software, and to permit persons to whom the Software is
> + * furnished to do so, subject to the following conditions:
> + *
> + * The above copyright notice and this permission notice shall be included in
> + * all copies or substantial portions of the Software.
> + *
> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
> THE
> + * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
> + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
> + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
> + * DEALINGS IN THE SOFTWARE.
> + *
> + * Copyright (C) 2013-2015 GlobalLogic Inc.
> + */
> +
> +#ifndef __XEN_PUBLIC_IO_XENSND_H__
> +#define __XEN_PUBLIC_IO_XENSND_H__
> +
> +/*
> + * Front->back notifications: When enqueuing a new request, sending a
> + * notification can be made conditional on req_event (i.e., the generic
> + * hold-off mechanism provided by the ring macros). Backends must set
> + * req_event 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 rsp_event (i.e., the generic
> + * hold-off mechanism provided by the ring macros). Frontends must set
> + * rsp_event appropriately (e.g., using RING_FINAL_CHECK_FOR_RESPONSES()).
> + */
> +
> +/*
> + * Feature and Parameter Negotiation
> + * =================================
> + * The two halves of a Para-virtual sound card driver utilize nodes within
> the
> + * XenStore to communicate capabilities and to negotiate operating
> parameters.
> + * This section enumerates these nodes which reside in the respective front
> and
> + * backend portions of the XenStore, following the XenBus convention.
> + *
> + * All data in the 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
> +
> *****************************************************************************
> + *
> + *------------------------- Backend Device parameters
> -------------------------
> + *
> + * devid
> + * Values: <uint32_t>
> + *
> + * Index of the soundcard which will be created in the frontend. This
> + * index is zero based.
> + *
> + * streams_cnt
> + * Values: <uint32_t>
> + *
> + * Streams count for virtualized soundcard.
> + *
> + *----------------------------- Streams settings
> ------------------------------
> + *
> + * Every virtualized device has own set of the sound streams. Each stream
> + * parameter is with index "%u" and defined as 'stream%u_???'. Stream index
> is
> + * zero based and should be continuous in range from 0 to 'streams_cnt' - 1.
> + *
> + * stream%u_channels
> + * Values: <uint32_t>
> + *
> + * The maximum amount of channels that can be supported by this stream.
> + * Should be from 1 to XENSND_MAX_CHANNELS_PER_STREAM.
> + *
> + * stream%u_type
> + * Values: "p", "c"
> + *
> + * Stream type: "p" - playback stream, "c" - capture stream.
> + *
> + * stream%u_bedev
> + * Values: string
> + *
> + * Name of the sound device which is mapped to this stream by the
> backend.
> + *
> + * stream%u_devid
> + * Values: <uint32_t>
> + *
> + * Index of the PCM instance which is created by the soundcard
> + * in the frontend.
> + *
> +
> *****************************************************************************
> + * Frontend XenBus Nodes
> +
> *****************************************************************************
> + *
> + *----------------------- 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
> + * the sole page in a single page sized ring buffer.
> + */
> +
> +/*
> + * STATE DIAGRAMS
> + *
> +
> *****************************************************************************
> + * Startup
> *
> +
> *****************************************************************************
> + *
> + * Tool stack creates front and back nodes with state
> XenbusStateInitialising.
> + *
> + * Front Back
> + * ================================= =====================================
> + * XenbusStateInitialising XenbusStateInitialising
> + * o Query virtual device o Query backend device
> identification
> + * properties. data.
> + * o Setup OS device instance. o Open and validate backend device.
> + * o Publish backend features and
> + * transport parameters.
> + * |
> + * |
> + * V
> + * XenbusStateInitWait
> + *
> + * o Query backend features and
> + * transport parameters.
> + * o Allocate and initialize the
> + * request ring.
> + * o Publish transport parameters
> + * that will be in effect during
> + * this connection.
> + * |
> + * |
> + * V
> + * XenbusStateInitialised
> + *
> + * o Query frontend transport
> parameters.
> + * o Connect to the request ring and
> + * event channel.
> + * o Publish backend device properties.
> + * |
> + * |
> + * V
> + * XenbusStateConnected
> + *
> + * o Query backend device properties.
> + * o Finalize OS virtual device
> + * instance.
> + * |
> + * |
> + * V
> + * XenbusStateConnected
> + *
> + * Note: Drivers that do not support any optional features, or the
> negotiation
> + * of transport parameters, can skip certain states in the state
> machine:
> + *
> + * o A frontend may transition to XenbusStateInitialised without
> + * waiting for the backend to enter XenbusStateInitWait. In this
> + * case, default transport parameters are in effect and any
> + * transport parameters published by the frontend must contain
> + * their default values.
> + *
> + * o A backend may transition to XenbusStateInitialised, bypassing
> + * XenbusStateInitWait, without waiting for the frontend to first
> + * enter the XenbusStateInitialised state. In this case, default
> + * transport parameters are in effect and any transport parameters
> + * published by the backend must contain their default values.
> + *
> + * Drivers that support optional features and/or transport parameter
> + * negotiation must tolerate these additional state transition paths.
> + * In general this means performing the work of any skipped state
> + * transition, if it has not already been performed, in addition to the
> + * work associated with entry into the current state.
> + */
> +
> +/*
> + * 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 0
> +#define XENSND_PCM_FORMAT_U8 1
> +#define XENSND_PCM_FORMAT_S16_LE 2
> +#define XENSND_PCM_FORMAT_S16_BE 3
> +#define XENSND_PCM_FORMAT_U16_LE 4
> +#define XENSND_PCM_FORMAT_U16_BE 5
> +#define XENSND_PCM_FORMAT_S24_LE 6
> +#define XENSND_PCM_FORMAT_S24_BE 7
> +#define XENSND_PCM_FORMAT_U24_LE 8
> +#define XENSND_PCM_FORMAT_U24_BE 9
> +#define XENSND_PCM_FORMAT_S32_LE 10
> +#define XENSND_PCM_FORMAT_S32_BE 11
> +#define XENSND_PCM_FORMAT_U32_LE 12
> +#define XENSND_PCM_FORMAT_U32_BE 13
> +#define XENSND_PCM_FORMAT_F32_LE 14 /* 4-byte float, IEEE-754 32-bit,
> */
> +#define XENSND_PCM_FORMAT_F32_BE 15 /* range -1.0 to 1.0
> */
> +#define XENSND_PCM_FORMAT_F64_LE 16 /* 8-byte float, IEEE-754 64-bit,
> */
> +#define XENSND_PCM_FORMAT_F64_BE 17 /* range -1.0 to 1.0
> */
> +#define XENSND_PCM_FORMAT_IEC958_SUBFRAME_LE 18
> +#define XENSND_PCM_FORMAT_IEC958_SUBFRAME_BE 19
> +#define XENSND_PCM_FORMAT_MU_LAW 20
> +#define XENSND_PCM_FORMAT_A_LAW 21
> +#define XENSND_PCM_FORMAT_IMA_ADPCM 22
> +#define XENSND_PCM_FORMAT_MPEG 23
> +#define XENSND_PCM_FORMAT_GSM 24
> +#define XENSND_PCM_FORMAT_SPECIAL 31 /* Any other unspecified format */
> +
> +/*
> + * REQUEST CODES.
> + */
> +#define XENSND_OP_OPEN 0
> +#define XENSND_OP_CLOSE 1
> +#define XENSND_OP_READ 2
> +#define XENSND_OP_WRITE 3
> +#define XENSND_OP_SET_VOLUME 4
> +#define XENSND_OP_GET_VOLUME 5
> +
> +/*
> + * The maximum amount of shared pages which can be used in any request
> + * from the frontend driver to the backend driver
> + */
> +#define XENSND_MAX_PAGES_PER_REQUEST 10
> +
> +/* The maximum amount of channels per virtualized stream */
> +#define XENSND_MAX_CHANNELS_PER_STREAM 128
> +
> +/*
> + * STATUS RETURN CODES.
> + */
> + /* Operation failed for some unspecified reason (e. g. -EIO). */
> +#define XENSND_RSP_ERROR (-1)
> + /* Operation completed successfully. */
> +#define XENSND_RSP_OKAY 0
> +
> +/*
> + * Description of the protocol between frontend and backend driver.
> + *
> + * The two halves of a Para-virtual sound driver communicates with
> + * each to other using an shared page and event channel.
> + * Shared page contains a ring with request/response packets.
> + * All fields within the packet are always in little-endian byte order.
> + * Almost all fields within the packet are unsigned except
> + * the field 'status' in the responses packets which is signed.
> + *
> + *
> + * All request packets have the same length (64 bytes)
> + *
> + * Request open - open an pcm stream for playback or capture:
> + * 0 1 2 3 4 5 6 7 octet
> + * +-----+-----+-----+-----+-----+-----+-----+-----+
> + * | id |
> + * +-----+-----+-----+-----+-----+-----+-----+-----+
> + * | operation | stream_idx |
> + * +-----+-----+-----+-----+-----+-----+-----+-----+
> + * | pcm_format | pcm_channels |
> + * +-----+-----+-----+-----+-----+-----+-----+-----+
> + * | pcm_rate | reserved |
> + * +-----+-----+-----+-----+-----+-----+-----+-----+
> + * | reserved | reserved |
> + * +-----+-----+-----+-----+-----+-----+-----+-----+
> + * +/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/+
> + * +-----+-----+-----+-----+-----+-----+-----+-----+
> + * | reserved | reserved |
> + * +-----+-----+-----+-----+-----+-----+-----+-----+
> + *
> + * id - private guest value, echoed in resp
> + * operation - XENSND_OP_OPEN
> + * stream_idx - index of the stream (from 0 to 'streams_cnt' - 1.
> + * 'streams_cnt' is read from the XenStore)
> + * pcm_format - XENSND_PCM_FORMAT_???
> + * pcm_channels - channels count in stream
> + * pcm_rate - stream data rate
> + *
> + *
> + * Request close - close an opened pcm stream:
> + * 0 1 2 3 4 5 6 7 octet
> + * +-----+-----+-----+-----+-----+-----+-----+-----+
> + * | id |
> + * +-----+-----+-----+-----+-----+-----+-----+-----+
> + * | operation | stream_idx |
> + * +-----+-----+-----+-----+-----+-----+-----+-----+
> + * | reserved | reserved |
> + * +-----+-----+-----+-----+-----+-----+-----+-----+
> + * +/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/+
> + * +-----+-----+-----+-----+-----+-----+-----+-----+
> + * | reserved | reserved |
> + * +-----+-----+-----+-----+-----+-----+-----+-----+
> + *
> + * id - private guest value, echoed in resp
> + * operation - XENSND_OP_CLOSE
> + * stream_idx - index of the stream (from 0 to 'streams_cnt' - 1.
> + * 'streams_cnt' is read from the XenStore)
> + *
> + *
> + * Request read/write - used for read (for capture) or write (for playback):
> + * 0 1 2 3 4 5 6 7 octet
> + * +-----+-----+-----+-----+-----+-----+-----+-----+
> + * | id |
> + * +-----+-----+-----+-----+-----+-----+-----+-----+
> + * | operation | stream_idx |
> + * +-----+-----+-----+-----+-----+-----+-----+-----+
> + * | length | gref0 |
> + * +-----+-----+-----+-----+-----+-----+-----+-----+
> + * | gref1 | gref2 |
> + * +-----+-----+-----+-----+-----+-----+-----+-----+
> + * +/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/+
> + * +-----+-----+-----+-----+-----+-----+-----+-----+
> + * | gref9 | reserved |
> + * +-----+-----+-----+-----+-----+-----+-----+-----+
> + *
> + * id - private guest value, echoed in resp
> + * operation - XENSND_OP_READ or XENSND_OP_WRITE
> + * stream_idx - index of the stream (from 0 to 'streams_cnt' - 1.
> + * 'streams_cnt' is read from the XenStore)
> + * length - read or write data length
> + * gref0 - gref9 - references to a grant entries for used pages in read/write
> + * request.
> + *
> + *
> + * Request set volume - set/get channels volume in stream:
> + * 0 1 2 3 4 5 6 7 octet
> + * +-----+-----+-----+-----+-----+-----+-----+-----+
> + * | id |
> + * +-----+-----+-----+-----+-----+-----+-----+-----+
> + * | operation | stream_idx |
> + * +-----+-----+-----+-----+-----+-----+-----+-----+
> + * | gref | reserved |
> + * +-----+-----+-----+-----+-----+-----+-----+-----+
> + * | reserved | reserved |
> + * +-----+-----+-----+-----+-----+-----+-----+-----+
> + * +/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/+
> + * +-----+-----+-----+-----+-----+-----+-----+-----+
> + * | reserved | reserved |
> + * +-----+-----+-----+-----+-----+-----+-----+-----+
> + *
> + * id - private guest value, echoed in resp
> + * operation - XENSND_OP_SET_VOLUME or XENSND_OP_GET_VOLUME
> + * stream_idx - index of the stream (from 0 to 'streams_cnt' - 1.
> + * 'streams_cnt' is read from the XenStore)
> + * gref - references to a grant entry for page with the volume values
> + *
> + *
> + * Shared page for set/get volume:
> + *
> + * 0 1 2 3 4 5 6 7 octet
> + * +-----+-----+-----+-----+-----+-----+-----+-----+
> + * | vol_ch0 | vol_ch1 |
> + * +-----+-----+-----+-----+-----+-----+-----+-----+
> + * | vol_ch2 | vol_ch3 |
> + * +-----+-----+-----+-----+-----+-----+-----+-----+
> + * +/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/+
> + * +-----+-----+-----+-----+-----+-----+-----+-----+
> + * | vol_ch126 | vol_ch127 |
> + * +-----+-----+-----+-----+-----+-----+-----+-----+
> + *
> + * vol_ch0 - vol_ch127 - volume for the channel from 0 to
> + * XENSND_MAX_CHANNELS_PER_STREAM
> + * Please, note that only first 'stream%u_channels' are used in this command,
> + * where 'stream%u_channels' is read from the XenStore (channels count for
> + * stream with index '%u' which equals to 'stream_idx')
> + *
> + *
> + * All response packets have the same length (64 bytes)
> + *
> + * Response for all requests:
> + * 0 1 2 3 4 5 6 7 octet
> + * +-----+-----+-----+-----+-----+-----+-----+-----+
> + * | id |
> + * +-----+-----+-----+-----+-----+-----+-----+-----+
> + * | operation | status |
> + * +-----+-----+-----+-----+-----+-----+-----+-----+
> + * | stream_idx | reserved |
> + * +-----+-----+-----+-----+-----+-----+-----+-----+
> + * | reserved | reserved |
> + * +-----+-----+-----+-----+-----+-----+-----+-----+
> + * +/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/+
> + * +-----+-----+-----+-----+-----+-----+-----+-----+
> + * | reserved | reserved |
> + * +-----+-----+-----+-----+-----+-----+-----+-----+
> + *
> + * id - copied from request
> + * stream_idx - copied from request
> + * operation - XENSND_OP_??? - copied from request
> + * status - XENSND_RSP_???
> + */
> +
> +struct xensnd_request {
> + uint8_t raw[64];
> +};
> +
> +struct xensnd_response {
> + uint8_t raw[64];
> +};
> +
> +DEFINE_RING_TYPES(xensnd, struct xensnd_request, struct xensnd_response);
> +
> +#endif /* __XEN_PUBLIC_IO_XENSND_H__ */
> --
> 1.9.1
Hi to all.
Could anybody confirm that this interface could be used for PV sound driver?
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