audio: host-zephyr: make component usable from user-space

[kv2019i]

Ensure an allocation context object is passed correctly whenever memory is allocated in the component. This allows to run the component both in kernel and user space.

[kv2019i]

For context, part of #10558

[Copilot]

Pull request overview

Note

Copilot was unable to run its full agentic suite in this review.

This PR updates the Zephyr host audio component to consistently pass an allocation context/heap into memory allocation APIs, enabling the component to run correctly in both kernel and user-space.

Changes:

• Add alloc_ctx to struct host_data to carry allocation context information.
• Use hd->alloc_ctx.heap when allocating/freeing DMA scatter-gather elements and DMA-related configs.
• Initialize hd->alloc_ctx.heap for user-space low-latency builds via zephyr_ll_user_heap().

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 3 comments.

File	Description
src/audio/host-zephyr.c	Routes allocations/frees through hd->alloc_ctx.heap and sets user-space heap under CONFIG_SOF_USERSPACE_LL.
src/audio/copier/host_copier.h	Adds struct mod_alloc_ctx alloc_ctx to struct host_data.

[kv2019i]

V2 pushed:

• address copilot comments, not functional changes to code

[lyakh]

I'd use NULL here directly just like you do in host_free()

[kv2019i]

@lyakh Same comment as in dai-zephyr.c PR #10801 . Given we need to use same value in two places in this function, I prefer to use a variable and single "NULL". host_free() has a single magic NULL, so that's a bit different.

[kv2019i]

Anymore reviews anyone, I'll proceed with merge end-of-day if no new comments.