[PATCH 0/5] for-linux/sndif: add explicit back and front synchronization

[PATCH 0/5] for-linux/sndif: add explicit back and front synchronization

[Oleksandr Andrushchenko]

Hello, all!

This is the syncup version of the sound protocol changes for
Linux Kernel with the only difference from the corresponding Xen
version being spaces to tabs conversion. Regradless of this only
change I have dropped R-b tags received for Xen version.

In order to provide explicit synchronization between backend and
frontend the following changes are introduced in the protocol:
 - bump protocol version to 2
 - add new ring buffer for sending asynchronous events from
   backend to frontend to report number of bytes played by the
   frontend (XENSND_EVT_CUR_POS)
 - introduce trigger events for playback control: start/stop/pause/resume
 - add "req-" prefix to event-channel and ring-ref to unify naming
   of the Xen event channels for requests and events
 - add XENSND_OP_HW_PARAM_QUERY request to read/update
   stream configuration space: request passes desired intervals/formats for
   the stream parameters and the response returns allowed intervals and
   formats mask that can be used.
 - MAJOR: changed req/resp/evt packet sizes from 32 to 64 octets
 -  Reworked XENSND_OP_HW_PARAM_QUERY so it now sends all
   parameters at once, allowing to check all the configuration
   space.
 - Minor documentation cleanup (added missed "reserved" fields)

Oleksandr Andrushchenko (5):
  xen/sndif: Introduce protocol version
  xen/sndif: Fix missed "reserved" fields in comments
  xen/sndif: Make requests and responses 64 octets long
  xen/sndif: Add explicit back and front synchronization
  xen/sndif: Add explicit back and front parameter negotiation

 include/xen/interface/io/sndif.h | 322 +++++++++++++++++++++++++++++--
 1 file changed, 306 insertions(+), 16 deletions(-)

-- 
2.17.0

[PATCH 1/5] xen/sndif: Introduce protocol version

[Oleksandr Andrushchenko]

Protocol version was referenced in the protocol description,
but missed its definition. Fix this by adding a constant
for current protocol version.

Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
---
 include/xen/interface/io/sndif.h | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/include/xen/interface/io/sndif.h b/include/xen/interface/io/sndif.h
index 5c918276835e..fc1752cf5a16 100644
--- a/include/xen/interface/io/sndif.h
+++ b/include/xen/interface/io/sndif.h
@@ -36,6 +36,13 @@
 #include "ring.h"
 #include "../grant_table.h"
 
+/*
+ ******************************************************************************
+ *                           Protocol version
+ ******************************************************************************
+ */
+#define XENSND_PROTOCOL_VERSION	1
+
 /*
  ******************************************************************************
  *                  Feature and Parameter Negotiation
-- 
2.17.0

[PATCH 2/5] xen/sndif: Fix missed "reserved" fields in comments

[Oleksandr Andrushchenko]

Some of the request descriptions have "reserved" fields
missed: fix this by adding corresponidng entries.

Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
---
 include/xen/interface/io/sndif.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/include/xen/interface/io/sndif.h b/include/xen/interface/io/sndif.h
index fc1752cf5a16..b775df96f021 100644
--- a/include/xen/interface/io/sndif.h
+++ b/include/xen/interface/io/sndif.h
@@ -680,6 +680,8 @@ struct xensnd_rw_req {
  * +----------------+----------------+----------------+----------------+
  * |                              length                               | 16
  * +----------------+----------------+----------------+----------------+
+ * |                             reserved                              | 20
+ * +----------------+----------------+----------------+----------------+
  * |/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/|
  * +----------------+----------------+----------------+----------------+
  * |                             reserved                              | 32
@@ -720,6 +722,8 @@ struct xensnd_rw_req {
  * +----------------+----------------+----------------+----------------+
  * |                              length                               | 16
  * +----------------+----------------+----------------+----------------+
+ * |                             reserved                              | 20
+ * +----------------+----------------+----------------+----------------+
  * |/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/|
  * +----------------+----------------+----------------+----------------+
  * |                             reserved                              | 32
-- 
2.17.0

[PATCH 3/5] xen/sndif: Make requests and responses 64 octets long

[Oleksandr Andrushchenko]

Extend the size of the requests and responses to 64 octets.
Bump protocol version to 2.

Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
---
 include/xen/interface/io/sndif.h | 22 +++++++++++-----------
 1 file changed, 11 insertions(+), 11 deletions(-)

diff --git a/include/xen/interface/io/sndif.h b/include/xen/interface/io/sndif.h
index b775df96f021..d48175f1a3d2 100644
--- a/include/xen/interface/io/sndif.h
+++ b/include/xen/interface/io/sndif.h
@@ -41,7 +41,7 @@
  *                           Protocol version
  ******************************************************************************
  */
-#define XENSND_PROTOCOL_VERSION	1
+#define XENSND_PROTOCOL_VERSION	2
 
 /*
  ******************************************************************************
@@ -533,7 +533,7 @@
  *
  *---------------------------------- Requests ---------------------------------
  *
- * All request packets have the same length (32 octets)
+ * All request packets have the same length (64 octets)
  * All request packets have common header:
  *         0                1                 2               3        octet
  * +----------------+----------------+----------------+----------------+
@@ -570,7 +570,7 @@
  * +----------------+----------------+----------------+----------------+
  * |/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/|
  * +----------------+----------------+----------------+----------------+
- * |                             reserved                              | 32
+ * |                             reserved                              | 64
  * +----------------+----------------+----------------+----------------+
  *
  * pcm_rate - uint32_t, stream data rate, Hz
@@ -639,7 +639,7 @@ struct xensnd_page_directory {
  * +----------------+----------------+----------------+----------------+
  * |/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/|
  * +----------------+----------------+----------------+----------------+
- * |                             reserved                              | 32
+ * |                             reserved                              | 64
  * +----------------+----------------+----------------+----------------+
  *
  * Request read/write - used for read (for capture) or write (for playback):
@@ -657,7 +657,7 @@ struct xensnd_page_directory {
  * +----------------+----------------+----------------+----------------+
  * |/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/|
  * +----------------+----------------+----------------+----------------+
- * |                             reserved                              | 32
+ * |                             reserved                              | 64
  * +----------------+----------------+----------------+----------------+
  *
  * operation - XENSND_OP_READ for read or XENSND_OP_WRITE for write
@@ -684,7 +684,7 @@ struct xensnd_rw_req {
  * +----------------+----------------+----------------+----------------+
  * |/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/|
  * +----------------+----------------+----------------+----------------+
- * |                             reserved                              | 32
+ * |                             reserved                              | 64
  * +----------------+----------------+----------------+----------------+
  *
  * operation - XENSND_OP_SET_VOLUME for volume set
@@ -726,7 +726,7 @@ struct xensnd_rw_req {
  * +----------------+----------------+----------------+----------------+
  * |/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/|
  * +----------------+----------------+----------------+----------------+
- * |                             reserved                              | 32
+ * |                             reserved                              | 64
  * +----------------+----------------+----------------+----------------+
  *
  * operation - XENSND_OP_MUTE for mute or XENSND_OP_UNMUTE for unmute
@@ -759,7 +759,7 @@ struct xensnd_rw_req {
 /*
  *---------------------------------- Responses --------------------------------
  *
- * All response packets have the same length (32 octets)
+ * All response packets have the same length (64 octets)
  *
  * Response for all requests:
  *         0                1                 2               3        octet
@@ -772,7 +772,7 @@ struct xensnd_rw_req {
  * +----------------+----------------+----------------+----------------+
  * |/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/|
  * +----------------+----------------+----------------+----------------+
- * |                             reserved                              | 32
+ * |                             reserved                              | 64
  * +----------------+----------------+----------------+----------------+
  *
  * id - uint16_t, copied from the request
@@ -787,7 +787,7 @@ struct xensnd_req {
 	union {
 		struct xensnd_open_req open;
 		struct xensnd_rw_req rw;
-		uint8_t reserved[24];
+		uint8_t reserved[56];
 	} op;
 };
 
@@ -796,7 +796,7 @@ struct xensnd_resp {
 	uint8_t operation;
 	uint8_t reserved;
 	int32_t status;
-	uint8_t reserved1[24];
+	uint8_t reserved1[56];
 };
 
 DEFINE_RING_TYPES(xen_sndif, struct xensnd_req, struct xensnd_resp);
-- 
2.17.0

[PATCH 4/5] xen/sndif: Add explicit back and front synchronization

[Oleksandr Andrushchenko]

In order to provide explicit synchronization between backend and
frontend the following changes are introduced in the protocol:
 - add new ring buffer for sending asynchronous events from
   backend to frontend to report number of bytes played by the
   frontend (XENSND_EVT_CUR_POS)
 - introduce trigger events for playback control: start/stop/pause/resume
 - add "req-" prefix to event-channel and ring-ref to unify naming
   of the Xen event channels for requests and events

Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
Signed-off-by: Oleksandr Grytsov <oleksandr_grytsov@epam.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Takashi Iwai <tiwai@suse.de>
---
 include/xen/interface/io/sndif.h | 162 ++++++++++++++++++++++++++++++-
 1 file changed, 161 insertions(+), 1 deletion(-)

diff --git a/include/xen/interface/io/sndif.h b/include/xen/interface/io/sndif.h
index d48175f1a3d2..131c3b469d4a 100644
--- a/include/xen/interface/io/sndif.h
+++ b/include/xen/interface/io/sndif.h
@@ -113,6 +113,8 @@
  *
  * /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 ----------------------------
  *
@@ -122,6 +124,8 @@
  *
  * /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 --------------------------------
  *
@@ -135,6 +139,8 @@
  *
  * /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 --------------------------------
  *
@@ -147,6 +153,8 @@
  *
  * /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
@@ -292,6 +300,23 @@
  *      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
  ******************************************************************************
@@ -439,6 +464,19 @@
 #define XENSND_OP_GET_VOLUME		5
 #define XENSND_OP_MUTE			6
 #define XENSND_OP_UNMUTE		7
+#define XENSND_OP_TRIGGER		8
+
+#define XENSND_OP_TRIGGER_START		0
+#define XENSND_OP_TRIGGER_PAUSE		1
+#define XENSND_OP_TRIGGER_STOP		2
+#define XENSND_OP_TRIGGER_RESUME	3
+
+/*
+ ******************************************************************************
+ *                                 EVENT CODES
+ ******************************************************************************
+ */
+#define XENSND_EVT_CUR_POS		0
 
 /*
  ******************************************************************************
@@ -455,6 +493,8 @@
 #define XENSND_FIELD_VCARD_LONG_NAME	"long-name"
 #define XENSND_FIELD_RING_REF		"ring-ref"
 #define XENSND_FIELD_EVT_CHNL		"event-channel"
+#define XENSND_FIELD_EVT_RING_REF	"evt-ring-ref"
+#define XENSND_FIELD_EVT_EVT_CHNL	"evt-event-channel"
 #define XENSND_FIELD_DEVICE_NAME	"name"
 #define XENSND_FIELD_TYPE		"type"
 #define XENSND_FIELD_STREAM_UNIQUE_ID	"unique-id"
@@ -566,7 +606,9 @@
  * +----------------+----------------+----------------+----------------+
  * |                           gref_directory                          | 24
  * +----------------+----------------+----------------+----------------+
- * |                             reserved                              | 28
+ * |                             period_sz                             | 28
+ * +----------------+----------------+----------------+----------------+
+ * |                             reserved                              | 32
  * +----------------+----------------+----------------+----------------+
  * |/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/|
  * +----------------+----------------+----------------+----------------+
@@ -578,6 +620,14 @@
  * 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,
@@ -592,6 +642,7 @@ struct xensnd_open_req {
 	uint16_t reserved;
 	uint32_t buffer_sz;
 	grant_ref_t gref_directory;
+	uint32_t period_sz;
 };
 
 /*
@@ -754,8 +805,32 @@ struct xensnd_rw_req {
  *
  * 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 {
+	uint8_t type;
+};
+
 /*
  *---------------------------------- Responses --------------------------------
  *
@@ -778,8 +853,51 @@ struct xensnd_rw_req {
  * 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
+ *
+ *----------------------------------- 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 {
+	uint64_t position;
+};
+
 struct xensnd_req {
 	uint16_t id;
 	uint8_t operation;
@@ -787,6 +905,7 @@ struct xensnd_req {
 	union {
 		struct xensnd_open_req open;
 		struct xensnd_rw_req rw;
+		struct xensnd_trigger_req trigger;
 		uint8_t reserved[56];
 	} op;
 };
@@ -799,6 +918,47 @@ struct xensnd_resp {
 	uint8_t reserved1[56];
 };
 
+struct xensnd_evt {
+	uint16_t id;
+	uint8_t type;
+	uint8_t reserved[5];
+	union {
+		struct xensnd_cur_pos_evt cur_pos;
+		uint8_t reserved[56];
+	} op;
+};
+
 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 {
+	uint32_t in_cons;
+	uint32_t in_prod;
+	uint8_t reserved[56];
+};
+
+#define XENSND_EVENT_PAGE_SIZE XEN_PAGE_SIZE
+#define XENSND_IN_RING_OFFS (sizeof(struct xensnd_event_page))
+#define XENSND_IN_RING_SIZE (XENSND_EVENT_PAGE_SIZE - XENSND_IN_RING_OFFS)
+#define XENSND_IN_RING_LEN (XENSND_IN_RING_SIZE / sizeof(struct xensnd_evt))
+#define XENSND_IN_RING(page) \
+	((struct xensnd_evt *)((char *)(page) + XENSND_IN_RING_OFFS))
+#define XENSND_IN_RING_REF(page, idx) \
+	(XENSND_IN_RING((page))[(idx) % XENSND_IN_RING_LEN])
+
 #endif /* __XEN_PUBLIC_IO_SNDIF_H__ */
-- 
2.17.0

[PATCH 5/5] xen/sndif: Add explicit back and front parameter negotiation

[Oleksandr Andrushchenko]

In order to provide explicit stream parameter negotiation between
backend and frontend the following changes are introduced in the protocol:
add XENSND_OP_HW_PARAM_QUERY request to read/update
configuration space for the parameters given: request passes
desired parameter's intervals/masks and the response to this request
returns allowed min/max intervals/masks to be used.

Parameters supported by this request/response:
 - format mask
 - sample rate interval
 - number of channels interval
 - buffer size, interval, frames
 - period size, interval, frames

Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Takashi Iwai <tiwai@suse.de>
---
 include/xen/interface/io/sndif.h | 133 +++++++++++++++++++++++++++++--
 1 file changed, 126 insertions(+), 7 deletions(-)

diff --git a/include/xen/interface/io/sndif.h b/include/xen/interface/io/sndif.h
index 131c3b469d4a..78bb5d9f8d83 100644
--- a/include/xen/interface/io/sndif.h
+++ b/include/xen/interface/io/sndif.h
@@ -465,6 +465,7 @@
 #define XENSND_OP_MUTE			6
 #define XENSND_OP_UNMUTE		7
 #define XENSND_OP_TRIGGER		8
+#define XENSND_OP_HW_PARAM_QUERY	9
 
 #define XENSND_OP_TRIGGER_START		0
 #define XENSND_OP_TRIGGER_PAUSE		1
@@ -832,28 +833,142 @@ struct xensnd_trigger_req {
 };
 
 /*
- *---------------------------------- Responses --------------------------------
+ * Request stream parameter ranges: request intervals and
+ *   masks of supported ranges for stream configuration values.
  *
- * All response packets have the same length (64 octets)
+ *   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.
  *
- * Response for all requests:
  *         0                1                 2               3        octet
  * +----------------+----------------+----------------+----------------+
- * |               id                |    operation   |    reserved    | 4
+ * |               id                | _HW_PARAM_QUERY|    reserved    | 4
  * +----------------+----------------+----------------+----------------+
- * |                              status                               | 8
+ * |                             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                              | 12
+ * |                             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 {
+	uint64_t formats;
+	struct {
+		uint32_t min;
+		uint32_t max;
+	} rates;
+	struct {
+		uint32_t min;
+		uint32_t max;
+	} channels;
+	struct {
+		uint32_t min;
+		uint32_t max;
+	} buffer;
+	struct {
+		uint32_t min;
+		uint32_t max;
+	} period;
+};
+
+/*
+ *---------------------------------- 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
@@ -906,6 +1021,7 @@ struct xensnd_req {
 		struct xensnd_open_req open;
 		struct xensnd_rw_req rw;
 		struct xensnd_trigger_req trigger;
+		struct xensnd_query_hw_param hw_param;
 		uint8_t reserved[56];
 	} op;
 };
@@ -915,7 +1031,10 @@ struct xensnd_resp {
 	uint8_t operation;
 	uint8_t reserved;
 	int32_t status;
-	uint8_t reserved1[56];
+	union {
+		struct xensnd_query_hw_param hw_param;
+		uint8_t reserved1[56];
+	} resp;
 };
 
 struct xensnd_evt {
-- 
2.17.0

Re: [PATCH 0/5] for-linux/sndif: add explicit back and front synchronization

[Oleksandr Andrushchenko]

Hello, Konrad, Takashi!

Could you please review the *Linux Kernel* version of the changes?
As I said in the cover letter below there is no functional changes
comparing to the corresponding Xen version, but spaces to tabs.
Still, formally, I have to drop the R-b tags and request for the new review.

Thank you,
Oleksandr

P.S. Minus GlobalLogic e-mails which bounce

On 04/12/2018 07:00 PM, Oleksandr Andrushchenko wrote:
> Hello, all!
>
> This is the syncup version of the sound protocol changes for
> Linux Kernel with the only difference from the corresponding Xen
> version being spaces to tabs conversion. Regradless of this only
> change I have dropped R-b tags received for Xen version.
>
> In order to provide explicit synchronization between backend and
> frontend the following changes are introduced in the protocol:
>   - bump protocol version to 2
>   - add new ring buffer for sending asynchronous events from
>     backend to frontend to report number of bytes played by the
>     frontend (XENSND_EVT_CUR_POS)
>   - introduce trigger events for playback control: start/stop/pause/resume
>   - add "req-" prefix to event-channel and ring-ref to unify naming
>     of the Xen event channels for requests and events
>   - add XENSND_OP_HW_PARAM_QUERY request to read/update
>     stream configuration space: request passes desired intervals/formats for
>     the stream parameters and the response returns allowed intervals and
>     formats mask that can be used.
>   - MAJOR: changed req/resp/evt packet sizes from 32 to 64 octets
>   -  Reworked XENSND_OP_HW_PARAM_QUERY so it now sends all
>     parameters at once, allowing to check all the configuration
>     space.
>   - Minor documentation cleanup (added missed "reserved" fields)
>
> Oleksandr Andrushchenko (5):
>    xen/sndif: Introduce protocol version
>    xen/sndif: Fix missed "reserved" fields in comments
>    xen/sndif: Make requests and responses 64 octets long
>    xen/sndif: Add explicit back and front synchronization
>    xen/sndif: Add explicit back and front parameter negotiation
>
>   include/xen/interface/io/sndif.h | 322 +++++++++++++++++++++++++++++--
>   1 file changed, 306 insertions(+), 16 deletions(-)
>

Re: [PATCH 0/5] for-linux/sndif: add explicit back and front synchronization

[Oleksandr Andrushchenko]

On 04/12/2018 07:55 PM, Boris Ostrovsky wrote:
> On 04/12/2018 12:11 PM, Oleksandr Andrushchenko wrote:
>> Hello, Konrad, Takashi!
>>
>> Could you please review the *Linux Kernel* version of the changes?
>> As I said in the cover letter below there is no functional changes
>> comparing to the corresponding Xen version, but spaces to tabs.
>> Still, formally, I have to drop the R-b tags and request for the new
>> review.
> Is there any reason why this all can't be done in a single patch?
Just to preserve the history of the changes?
> This is just syncing up with the canonical definition in Xen.
Do you want me to squash and resend?
> -boris
>
>
Thank you,
Oleksandr

Re: [PATCH 0/5] for-linux/sndif: add explicit back and front synchronization

[Boris Ostrovsky]

On 04/12/2018 12:11 PM, Oleksandr Andrushchenko wrote:
> Hello, Konrad, Takashi!
>
> Could you please review the *Linux Kernel* version of the changes?
> As I said in the cover letter below there is no functional changes
> comparing to the corresponding Xen version, but spaces to tabs.
> Still, formally, I have to drop the R-b tags and request for the new
> review.

Is there any reason why this all can't be done in a single patch?

This is just syncing up with the canonical definition in Xen.

-boris

Re: [PATCH 0/5] for-linux/sndif: add explicit back and front synchronization

[Oleksandr Andrushchenko]

On 04/12/2018 08:13 PM, Boris Ostrovsky wrote:
> On 04/12/2018 12:55 PM, Oleksandr Andrushchenko wrote:
>> On 04/12/2018 07:55 PM, Boris Ostrovsky wrote:
>>> On 04/12/2018 12:11 PM, Oleksandr Andrushchenko wrote:
>>>> Hello, Konrad, Takashi!
>>>>
>>>> Could you please review the *Linux Kernel* version of the changes?
>>>> As I said in the cover letter below there is no functional changes
>>>> comparing to the corresponding Xen version, but spaces to tabs.
>>>> Still, formally, I have to drop the R-b tags and request for the new
>>>> review.
>>> Is there any reason why this all can't be done in a single patch?
>> Just to preserve the history of the changes?
> The history is tracked in Xen tree and since you are only updating the
> header file I don't think we gain much by repeating it here.
makes sense
>>> This is just syncing up with the canonical definition in Xen.
>> Do you want me to squash and resend?
>
> Yes, please.
will do
> -boris

Re: [PATCH 0/5] for-linux/sndif: add explicit back and front synchronization

[Boris Ostrovsky]

On 04/12/2018 12:55 PM, Oleksandr Andrushchenko wrote:
> On 04/12/2018 07:55 PM, Boris Ostrovsky wrote:
>> On 04/12/2018 12:11 PM, Oleksandr Andrushchenko wrote:
>>> Hello, Konrad, Takashi!
>>>
>>> Could you please review the *Linux Kernel* version of the changes?
>>> As I said in the cover letter below there is no functional changes
>>> comparing to the corresponding Xen version, but spaces to tabs.
>>> Still, formally, I have to drop the R-b tags and request for the new
>>> review.
>> Is there any reason why this all can't be done in a single patch?
> Just to preserve the history of the changes?

The history is tracked in Xen tree and since you are only updating the
header file I don't think we gain much by repeating it here.

>> This is just syncing up with the canonical definition in Xen.
> Do you want me to squash and resend?


Yes, please.

-boris