buffer: extend ability to allocate on specific heap to all functions

[kv2019i]

Complete making buffer.h compatible with user-space work.

Tested as part of the bigger #10558

[Copilot]

Pull request overview

Extends heap-specific allocation support for audio buffers to improve Zephyr userspace compatibility by removing rbrealloc*() usage and switching buffer allocations/frees to sof_heap_alloc() / sof_heap_free().

Changes:

• Removed rbrealloc_align() API and its platform/test implementations.
• Updated comp_buffer allocation/free paths to use heap-aware sof_heap_alloc() / sof_heap_free().
• Simplified buffer resize logic to allocate/free explicitly instead of reallocating.

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
zephyr/lib/alloc.c	Removes Zephyr-side rbrealloc_align() implementation (API cleanup).
zephyr/include/rtos/alloc.h	Removes rbrealloc*() declarations from Zephyr allocation API.
posix/include/rtos/alloc.h	Removes rbrealloc*() declarations from POSIX allocation API.
src/audio/buffers/comp_buffer.c	Switches buffer data allocation/free + resize to heap-aware APIs.
src/lib/alloc.c	Removes non-Zephyr rbrealloc_align() implementation.
src/platform/library/lib/alloc.c	Removes platform library rbrealloc_align() implementation.
test/cmocka/src/common_mocks.c	Removes mock rbrealloc_align() implementation to match API removal.

[Copilot]

In buffer_set_size(), when callers pass alignment==0 (e.g. module_adapter.c and copier_ipcgtw.c do), this now forwards 0 to sof_heap_alloc(). Previously the alignment==0 path used rbrealloc() which implicitly aligned to PLATFORM_DCACHE_ALIGN. To preserve behavior and avoid potentially invalid/insufficient alignment from the underlying heap, map alignment==0 to PLATFORM_DCACHE_ALIGN (or to audio_stream_get_align()/existing stream alignment) before calling sof_heap_alloc().

Suggested change

	if (!alignment)
	alignment = PLATFORM_DCACHE_ALIGN;

[kv2019i]

The same semantics are now implemented by sof_heap_alloc() so 0 can be passed forward to it.

[Copilot]

buffer_set_size_range(): the resize loop decrements new_size until it drops below minimum_size. If all allocations fail, new_ptr stays NULL and new_size will end up < minimum_size (often 0), but the function later calls buffer_init_stream(buffer, new_size). That can set an invalid size despite the earlier validation. Consider handling the “no allocation succeeded” case explicitly: for grow requests return -ENOMEM without changing the stream; for shrink requests skip allocating a new block and just set the stream size to the chosen target (>= minimum_size).

[kv2019i]

Fixed in V2.

[Copilot]

In buffer_set_size_range(), alignment is forwarded directly to sof_heap_alloc(). When alignment==0, earlier code used rbrealloc() (i.e., PLATFORM_DCACHE_ALIGN via the rbrealloc wrapper). To avoid potentially allocating buffers with weaker-than-expected alignment, consider normalizing alignment==0 to PLATFORM_DCACHE_ALIGN (or the stream’s current alignment) before the allocation loop.

[kv2019i]

sof_heap_alloc() implements these semantics for alignment==0, so no need to add a special case for PLATFORM_DCACHE_ALIGN here.