On Tue, Dec 19, 2023 at 06:08:15PM +0100, Pierre-Louis Bossart wrote: > On 12/19/23 17:53, Mark Brown wrote: > > On Tue, Dec 19, 2023 at 05:50:30PM +0100, Pierre-Louis Bossart wrote: > >>> grep for regmap_.*async - cs_dsp.c is the upstream example in a driver, > >>> or there's the rbtree cache sync code which uses a back door to go into > >>> an async mode. Basically just variants of all the normal regmap I/O > >>> calls with a _complete() call you can use to wait for everything to > >>> happen. The implementation is a bit heavyweight since it was written to > >>> work with fairly slow buses. > > > >> I spent a fair amount of time this afternoon trying to understand the > >> regmap_async parts, and I am not following where in the code there is an > >> ordering requirement/enforcement between async and sync usages. > > > > The only actual async implementation is SPI which processes things in > > order of submission, the sync API wraps the async API. > > > >> Also is this just me spacing out or there is no regmap_raw_read_async()? > > > > Right, there was never any need. > > ok. I am starting to think that we could have a new type of regmap, say > "regmap-sdw-bra", where the use of write_raw_async() would rely on the > send/wait bus primitives, and write_raw() would fallback to the regular > read/write commands. We'd need a mutual exclusion to prevent parallel > async/sync access to the same regmap. > > In other words, "memory" areas that are used for firmware downloads > would be moved to a different regmap with async capabilities and no > caching support. I would be a little inclined to say leave adding a regmap for a follow up series, whether we add it to the existing regmap or add a new one, or whatever, it should all sit happily on top of the API being added in this series. Makes it a little more contained to focus on one area at a time, and leave this series as adding core support for BRA. But that said, if we really want to I don't feel mega strongly on this one. Thanks, Charles
