dma: dma_sg: allocate on specific heap

[kv2019i]

Add a heap parameter to DMA scatter-gather allocation interface. This makes it possible to control how allocations are done for the DMA buffers.

[kv2019i]

For context, this is part of #10558

[Copilot]

Pull request overview

This PR extends the DMA scatter-gather (SG) allocation/free interface to accept an explicit Zephyr heap pointer, enabling callers to control which heap backs SG element allocations.

Changes:

• Add struct k_heap *heap parameter to dma_sg_alloc() / dma_sg_free() declarations and definitions.
• Switch SG element allocation/free to sof_heap_alloc() / sof_heap_free() and explicitly zero-initialize the allocated element array.
• Update all current call sites to pass NULL for the heap (default heap behavior).

Reviewed changes

Copilot reviewed 11 out of 11 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
zephyr/include/sof/lib/dma.h	Updates SG API prototypes to include a heap parameter.
posix/include/sof/lib/dma.h	Mirrors the SG API prototype changes for the POSIX build.
src/lib/dma.c	Implements heap-aware SG allocation/free using sof_heap_alloc/free and adds explicit zeroing.
src/trace/dma-trace.c	Adjusts SG free call to pass NULL heap.
src/probe/probe.c	Adjusts SG alloc/free calls to pass NULL heap.
src/ipc/ipc3/host-page-table.c	Adjusts SG free call to pass NULL heap on error path.
src/ipc/ipc3/handler.c	Adjusts SG free call to pass NULL heap on error path.
src/audio/host-zephyr.c	Adjusts SG alloc/free calls to pass NULL heap.
src/audio/host-legacy.c	Adjusts SG alloc/free calls to pass NULL heap.
src/audio/dai-zephyr.c	Adjusts SG alloc/free calls to pass NULL heap.
src/audio/dai-legacy.c	Adjusts SG alloc/free calls to pass NULL heap.

[kv2019i]

@lyakh @jsarha @lgirdwood ping?

[lyakh]

@kv2019i so, now that we've merged vregions for modules - which heap would these dma_sg allocations be done on? If you meant to allocate them on module heap, then I think now you need to pass a struct mod_alloc_ctx * as a parameter instead of struct k_heap *?

[lgirdwood]

@kv2019i so, now that we've merged vregions for modules - which heap would these dma_sg allocations be done on? If you meant to allocate them on module heap, then I think now you need to pass a struct mod_alloc_ctx * as a parameter instead of struct k_heap *?

@kv2019i if needed dont mind if you want to do this incrementally.

[kv2019i]

I think @lyakh and @lgirdwood we could do this incrementally. The users of this interface (DAI and host code) is not yet converted to use vregions (e.g. create_local_elems() in host-zephyr.c). So I cannot immediately convert this PR to vregions yet.

[kv2019i]

Moving to draft until next rebase of #10558 (to see how move to vregions changes, or does not change, this PR).