[DNM-RFC] Pipeline 2.0 discussions

[marcinszkudlinski]

DO NOT MERGE - DISCUSSION ONLY

After long time I could proceed with Pipeline 2.0 design

To make tracking changes and discussions easier, I translated the initial discussion to .rst format an put it on my private branch

Initial headsup:
thesofproject/sof#7261

discussion and 1st version of the document
https://github.com/orgs/thesofproject/discussions/8645

current version of the document:

https://marcinszkudlinski.github.io/sof-docs/PAGES/architectures/firmware/sof-common/pipeline_2_0/pipeline2_0_discussion.html

the above HTML is a compilation of this PR

please - read it and comment in this PR. I will add all changes as commits to this branch so we'll be able to track changes

[gbernatxintel]

Please include fast mode task in implementation Pipeline 2.0

[marcinszkudlinski]

sink/src APIs should have states. Based on a state, module would know if the sink/source has already been configured and if it is allowed to process data from if / put result to it

[lgirdwood]

@marcinszkudlinski I think pipeline 2.0 has made some recent progress upstream, do you think we will be able to target this PR in Q4 for merge or do you still have many code PRs pending ?

[marcinszkudlinski]

@lgirdwood
The main problem is changing all components/modules API to sink/src

currently the modules don't use any API for interaction with buffers, that makes any modifications extremely hard. The modules are bound hard to comp_buffer and some internal pipeline structures
I don't think we can target P2.0 for Q4, unless we'll find some resources to deal with the modules.

[marcinszkudlinski]

TODO: add probe support to generic sink/src - this should allow flawless work of probes at any point of pipeline