hw: Support multi-ID DMA

fischeti commented 3 months ago

The new iDMA supports multiple channels by instantiating multiple backends that can serve different streams independently to prevent ordering requirements.

TODO

[x] Set proper defaults in config
[x] Add test dma_mchan to verify independence and correctness of streams
[x] Additional HW configuration to test multi channel in CI
[x] Switch to proper release of iDMA once ready
[x] Evaluate overhead of multichannel iDMA and bigger Xbar (DMA grows from 76kGE to 296kGE; Wide Xbar from 110kGE to 186kGE) in a 4 channel configuration.
[x] Revert DMA ISA extension assembly instructions to .word for better interoperability with non-pulp toolchains

colluca commented 2 months ago

Version 0.6.3 of the iDMA has been released containing the mentioned changes. The iDMA in Snitch has already been bumped in https://github.com/pulp-platform/snitch_cluster/pull/156 so we can undraft this after rebasing on top of it.

fischeti commented 2 months ago

I see the programming interface of the DMA changes, specifically for what concerns the config field.

Can you also update the documentation accordingly?

I added the new config documentation as well now.

pulp-platform / snitch_cluster

hw: Support multi-ID DMA #144

TODO