[PATCH v4 1/3] ALSA: compress: document the compress audio state machine

[Vinod Koul]

So we had some discussions of the stream states, so I thought it is a
good idea to document the state transitions, so add it documentation

Reviewed-by: Charles Keepax <ckeepax at opensource.cirrus.com>
Signed-off-by: Vinod Koul <vkoul at kernel.org>
---
 .../sound/designs/compress-offload.rst        | 51 +++++++++++++++++++
 1 file changed, 51 insertions(+)

diff --git a/Documentation/sound/designs/compress-offload.rst b/Documentation/sound/designs/compress-offload.rst
index ad4bfbdacc83..b6e9025ae105 100644
--- a/Documentation/sound/designs/compress-offload.rst
+++ b/Documentation/sound/designs/compress-offload.rst
@@ -151,6 +151,57 @@ Modifications include:
 - Addition of encoding options when required (derived from OpenMAX IL)
 - Addition of rateControlSupported (missing in OpenMAX AL)
 
+State Machine
+=============
+
+The compressed audio stream state machine is described below ::
+
+                                        +----------+
+                                        |          |
+                                        |   OPEN   |
+                                        |          |
+                                        +----------+
+                                             |
+                                             |
+                                             | compr_set_params()
+                                             |
+                                             v
+         compr_free()                   +----------+
+  +------------------------------------|          |
+  |                                    |   SETUP  |
+  |          +------------------------>|          |<-------------------------+
+  |          | compr_drain_notify()    +----------+                          |
+  |          |         or                   |                                |
+  |          |      compr_stop()            |                                |
+  |          |                              | compr_write()                  |
+  |          |                              |                                |
+  |          |                              v                                |
+  |          |                         +----------+                          |
+  |          |                         |          |   compr_free()           |
+  |          |                         |  PREPARE |---------------> A        |
+  |          |                         |          |                          |
+  |          |                         +----------+                          |
+  |          |                              |                                |
+  |          |                              |                                |
+  |          |                              | compr_start()                  |
+  |          |                              |                                |
+  |          |                              v                                |
+  |    +----------+                    +----------+                          |
+  |    |          |    compr_drain()   |          |        compr_stop()      |
+  |    |  DRAIN   |<-------------------|  RUNNING |--------------------------+
+  |    |          |                    |          |                          |
+  |    +----------+                    +----------+                          |
+  |                                       |    ^                             |
+  |          A                            |    |                             |
+  |          |              compr_pause() |    | compr_resume()              |
+  |          |                            |    |                             |
+  |          v                            v    |                             |
+  |    +----------+                   +----------+                           |
+  |    |          |                   |          |         compr_stop()      |
+  +--->|   FREE   |                   |  PAUSE   |---------------------------+
+       |          |                   |          |
+       +----------+                   +----------+
+
 
 Gapless Playback
 ================
-- 
2.26.2