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

[Vinod Koul <vkoul@kernel.org>]

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

Signed-off-by: Vinod Koul <vkoul@kernel.org>
---
 .../sound/designs/compress-offload.rst        | 52 +++++++++++++++++++
 1 file changed, 52 insertions(+)

diff --git a/Documentation/sound/designs/compress-offload.rst b/Documentation/sound/designs/compress-offload.rst
index ad4bfbdacc83..7292717c43bf 100644
--- a/Documentation/sound/designs/compress-offload.rst
+++ b/Documentation/sound/designs/compress-offload.rst
@@ -151,6 +151,58 @@ 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_drain_notify()    |          |
+              +------------------------>|   SETUP  |
+              |                         |          |
+              |                         +----------+
+              |                              |
+              |                              |
+              |                              | compr_write()
+              |                              |
+              |                              V
+              |                         +----------+
+              |                         |          |
+              |                         |  PREPARE |
+              |                         |          |
+              |                         +----------+
+              |                              |
+              |                              |
+              |                              | compr_start()
+              |                              |
+              |                              V
+        +----------+                    +----------+     compr_pause()      +----------+
+        |          |                    |          |----------------------->|          |
+        |  DRAIN   |<-------------------|  RUNNING |                        |  PAUSE   |
+        |          |                    |          |<-----------------------|          |
+        +----------+                    +----------+     compr_resume()     +----------+
+              |                              |
+              |                              |
+              |                              | compr_free()
+              |                              |
+              |                              V
+              |                         +----------+
+              |     compr_free()        |          |
+              +------------------------>|          |
+                                        |   STOP   |
+                                        |          |
+                                        +----------+
+
 
 Gapless Playback
 ================
-- 
2.26.2