[PATCH v4] sndif: add ABI for Para-virtual sound

[Oleksandr Dmytryshyn <oleksandr.dmytryshyn@globallogic.com>]

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@globallogic.com>
Signed-off-by: Iurii Konovalenko <iurii.konovalenko@globallogic.com>
---
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

 xen/include/public/io/sndif.h | 338 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 338 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..b17af01
--- /dev/null
+++ b/xen/include/public/io/sndif.h
@@ -0,0 +1,338 @@
+/******************************************************************************
+ * 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__
+
+/*
+ * Feature and Parameter Negotiation
+ * =================================
+ * The two halves of a Para-virtual sound 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.
+ *
+ * XenStore nodes in sections marked "PRIVATE" are solely for use by the
+ * driver side whose XenBus tree contains them.
+ *
+ *****************************************************************************
+ *                            Backend XenBus Nodes
+ *****************************************************************************
+ *
+ *------------------ Backend Device Identification (PRIVATE) ------------------
+ *
+ * stream_id
+ *      Values:         <uint32_t>
+ *
+ *      Each virtualized stream has own id starting from 0.
+ *      Within each frontend these ids must be unique.
+ *      Each stream can be opened only for playback or capture
+ *      at the same time.
+ *
+ * channels_cnt
+ *      Values:         <uint32_t>
+ *
+ *      The maximum amount of channels that can be supported by this stream.
+ *
+ *****************************************************************************
+ *                            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.
+ */
+
+/*
+ * 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    12
+
+/* The maximum amount of channels per virtualized stream */
+#define XENSND_MAX_CHANNELS_PER_STREAM  16
+
+/*
+ * 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 the frontend and the 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 (80 bytes)
+ *
+ * Request open - open an pcm stream for playback or capture:
+ *     0    1     2     3     4     5     6     7  octet
+ * +-----+-----+-----+-----+-----+-----+-----+-----+
+ * |                      id                       |
+ * +-----+-----+-----+-----+-----+-----+-----+-----+
+ * |       operation       |        stream         |
+ * +-----+-----+-----+-----+-----+-----+-----+-----+
+ * |      pcm_format       |      pcm_channels     |
+ * +-----+-----+-----+-----+-----+-----+-----+-----+
+ * |       pcm_rate        |       pcm_type        |
+ * +-----+-----+-----+-----+-----+-----+-----+-----+
+ * |       reserved        |       reserved        |
+ * +-----+-----+-----+-----+-----+-----+-----+-----+
+ * +/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/+
+ * +-----+-----+-----+-----+-----+-----+-----+-----+
+ * |       reserved        |       reserved        |
+ * +-----+-----+-----+-----+-----+-----+-----+-----+
+ *
+ * id - private guest value, echoed in resp
+ * operation - XENSND_OP_OPEN
+ * stream - stream number
+ * pcm_format - XENSND_PCM_FORMAT_???
+ * pcm_channels - channels count in stream
+ * pcm_rate - stream data rate
+ * pcm_type - 0: playback, 1: capture
+ *
+ *
+ * Request close - close an opened pcm stream:
+ *     0    1     2     3     4     5     6     7  octet
+ * +-----+-----+-----+-----+-----+-----+-----+-----+
+ * |                      id                       |
+ * +-----+-----+-----+-----+-----+-----+-----+-----+
+ * |       operation       |        stream         |
+ * +-----+-----+-----+-----+-----+-----+-----+-----+
+ * |       reserved        |       reserved        |
+ * +-----+-----+-----+-----+-----+-----+-----+-----+
+ * +/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/+
+ * +-----+-----+-----+-----+-----+-----+-----+-----+
+ * |       reserved        |       reserved        |
+ * +-----+-----+-----+-----+-----+-----+-----+-----+
+ *
+ * id - private guest value, echoed in resp
+ * operation - XENSND_OP_CLOSE
+ * stream - stream number
+ *
+ *
+ * Request read/write - used for read (for capture) or write (for playback):
+ *     0    1     2     3     4     5     6     7  octet
+ * +-----+-----+-----+-----+-----+-----+-----+-----+
+ * |                      id                       |
+ * +-----+-----+-----+-----+-----+-----+-----+-----+
+ * |       operation       |        stream         |
+ * +-----+-----+-----+-----+-----+-----+-----+-----+
+ * |         length        |         gref0         |
+ * +-----+-----+-----+-----+-----+-----+-----+-----+
+ * |         gref1         |         gref2         |
+ * +-----+-----+-----+-----+-----+-----+-----+-----+
+ * +/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/+
+ * +-----+-----+-----+-----+-----+-----+-----+-----+
+ * |         gref11        |       reserved        |
+ * +-----+-----+-----+-----+-----+-----+-----+-----+
+ * |       reserved        |       reserved        |
+ * +-----+-----+-----+-----+-----+-----+-----+-----+
+ *
+ * id - private guest value, echoed in resp
+ * operation - XENSND_OP_READ or XENSND_OP_WRITE
+ * stream - stream id number
+ * length - read or write data length
+ * gref0 - gref11 - references to a grant entries for used pages in read/write
+ * request.
+ *
+ *
+ * Request set volume - set channels volume in stream:
+ *     0    1     2     3     4     5     6     7  octet
+ * +-----+-----+-----+-----+-----+-----+-----+-----+
+ * |                      id                       |
+ * +-----+-----+-----+-----+-----+-----+-----+-----+
+ * |       operation       |        stream         |
+ * +-----+-----+-----+-----+-----+-----+-----+-----+
+ * |        vol_ch0        |        vol_ch1        |
+ * +-----+-----+-----+-----+-----+-----+-----+-----+
+ * |        vol_ch2        |        vol_ch3        |
+ * +-----+-----+-----+-----+-----+-----+-----+-----+
+ * |        vol_ch4        |        vol_ch5        |
+ * +-----+-----+-----+-----+-----+-----+-----+-----+
+ * +/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/+
+ * +-----+-----+-----+-----+-----+-----+-----+-----+
+ * |        vol_ch14       |        vol_ch15       |
+ * +-----+-----+-----+-----+-----+-----+-----+-----+
+ *
+ * id - private guest value, echoed in resp
+ * operation - XENSND_OP_SET_VOLUME
+ * stream - stream number
+ * vol_ch0 - vol_ch15 - volume level for channel0 - channel15
+ *
+ *
+ * Request get volume - get channels volume in stream:
+ *     0    1     2     3     4     5     6     7  octet
+ * +-----+-----+-----+-----+-----+-----+-----+-----+
+ * |                      id                       |
+ * +-----+-----+-----+-----+-----+-----+-----+-----+
+ * |       operation       |        stream         |
+ * +-----+-----+-----+-----+-----+-----+-----+-----+
+ * |       reserved        |       reserved        |
+ * +-----+-----+-----+-----+-----+-----+-----+-----+
+ * |       reserved        |       reserved        |
+ * +-----+-----+-----+-----+-----+-----+-----+-----+
+ * |       reserved        |       reserved        |
+ * +-----+-----+-----+-----+-----+-----+-----+-----+
+ * +/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/+
+ * +-----+-----+-----+-----+-----+-----+-----+-----+
+ * |       reserved        |       reserved        |
+ * +-----+-----+-----+-----+-----+-----+-----+-----+
+ *
+ * id - private guest value, echoed in resp
+ * operation - XENSND_OP_GET_VOLUME
+ * stream - stream number
+ *
+ *
+ * All response packets have the same length (80 bytes)
+ *
+ * Response for all requests exept the XENSND_OP_GET_VOLUME:
+ *     0    1     2     3     4     5     6     7  octet
+ * +-----+-----+-----+-----+-----+-----+-----+-----+
+ * |       operation       |         status        |
+ * +-----+-----+-----+-----+-----+-----+-----+-----+
+ * |                      id                       |
+ * +-----+-----+-----+-----+-----+-----+-----+-----+
+ * |       reserved        |       reserved        |
+ * +-----+-----+-----+-----+-----+-----+-----+-----+
+ * |       reserved        |       reserved        |
+ * +-----+-----+-----+-----+-----+-----+-----+-----+
+ * +/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/+
+ * +-----+-----+-----+-----+-----+-----+-----+-----+
+ * |       reserved        |       reserved        |
+ * +-----+-----+-----+-----+-----+-----+-----+-----+
+ *
+ * operation - XENSND_OP_??? - copied from request
+ * status - XENSND_RSP_???
+ * id - copied from request
+ *
+ *
+ * Response for XENSND_OP_GET_VOLUME request:
+ *     0    1     2     3     4     5     6     7  octet
+ * +-----+-----+-----+-----+-----+-----+-----+-----+
+ * |       operation       |         status        |
+ * +-----+-----+-----+-----+-----+-----+-----+-----+
+ * |                      id                       |
+ * +-----+-----+-----+-----+-----+-----+-----+-----+
+ * |        vol_ch0        |        vol_ch1        |
+ * +-----+-----+-----+-----+-----+-----+-----+-----+
+ * |        vol_ch2        |        vol_ch3        |
+ * +-----+-----+-----+-----+-----+-----+-----+-----+
+ * +/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/+
+ * +-----+-----+-----+-----+-----+-----+-----+-----+
+ * |        vol_ch14       |        vol_ch15       |
+ * +-----+-----+-----+-----+-----+-----+-----+-----+
+ *
+ * operation - XENSND_OP_GET_VOLUME -copied from request
+ * status - XENSND_RSP_???
+ * id - copied from request
+ * vol_ch0 - vol_ch15 - volume level for channel0 - channel15
+ */
+
+struct xensnd_request {
+    uint8_t raw[80];
+};
+
+struct xensnd_response {
+    uint8_t raw[80];
+};
+
+DEFINE_RING_TYPES(xensnd, struct xensnd_request, struct xensnd_response);
+
+#endif /* __XEN_PUBLIC_IO_XENSND_H__ */
-- 
1.9.1