On Mon, Nov 14, 2016 at 10:50:10AM -0600, Pierre-Louis Bossart wrote:
+SoundWire stream states +======================= +Below figure shows the SoundWire stream states and possible state +transition diagram.
+|--------------| |-------------| |--------------| |--------------| +| ALLOC |---->| CONFIG |---->| PREPARE |---->| ENABLE | +| STATE | | STATE | | STATE | | STATE | +|--------------| |-------------| |--------------| |--------------|
^ || || || || \/- |--------------| |--------------| |--------------|
- | RELEASE |<--------------------| DEPREPARE |<----| DISABLE |
- | STATE | | STATE | | STATE |
- |--------------| |--------------| |--------------|
One minor comment, this looks very similar to the clock frameworks state model, but the clock framework calls it unprepare would there be some milage in aligning to?
The SoundWire spec uses de-prepare, e.g. "De-prepare_Finished" I'd rather stick to the wording between a spec and the implementation of said spec, rather than introduce a term/concept from an unrelated framework.
Cool we should leave that as is then :-)
+4. Once all the new values are programmed, bus initiates switch to +alternate bank. Once switch is successful, the port channels enabled on +previous bank for already active streams are disabled.
This last sentence makes no sense in this context, probably a copy/paste that shouldn't be there. The previously active streams remain active in this prepare step.
+5. Ports of Master and Slave for current stream are prepared.
+After all above operations are successful, stream state is set to +SDW_STATE_STRM_PREPARE.
+SDW_STATE_STRM_ENABLE: Enable state of stream. Operations performed +before entering in this state: +1. All the values computed in SDW_STATE_STRM_PREPARE state are +programmed in alternate bank (bank currently unused). It includes +programming of already active streams as well.
+2. All the Master and Slave port channels for the current stream are +enabled on alternate bank (bank currently unused).
This could probably use a little more explaination to show how it differs from step 3/4 in PREPARE, as it looks like all the computed values where applied there. I imagine this is just my lack of understanding rather than an actual issue but even looking at the code I am having a little difficulty tying up these two.
Yes, see above there was an extra sentence that isn't right.
sdw_prepare_op
- sdw_compute_params (prepare step 1/2)
- sdw_program_params (prepare step 3)
- sdw_update_bus_params (prepare step 4)
sdw_enable_op
- sdw_program_params (enable step 1)
- sdw_update_bus_params (enable step 2)
It looks like the params are still basically the same as they were when we called sdw_program_params in prepare.
The parameters are the same except for the channel-enable flags which are only programmed and activated via a bank switch in the enable step.
Ah ok that is what is getting pushed out there, thanks for explaining.
Thanks, Charles