ace: mm: tlb: Ignore unmapping error in driver initalization

[softwarecki]

The sys_mm_drv_unmap_region_initial function is responsible for unmapping all unused virtual memory during tlb driver initialization. Most addresses will not have a mapped page. Ignore the error code indicating unmapped memory that will occur when trying to unmap.

Fix for issue detected in: #78479

[lyakh]

@softwarecki you need to re-add your now reverted 311ddf9 too, right? Without it this PR doesn't really work?

[softwarecki]

Added previously reverted commit from #78227
Created PR in SOF to test this PR: thesofproject/sof#9504

[lyakh]

Added previously reverted commit from #78227 Created PR in SOF to test this PR: thesofproject/sof#9504

Thanks for adding a SOF PR. Since it has failed some tests, let me mark this PR "DNM" for now, feel free to remove the label once those failures are fixed

[softwarecki]

@lyakh Can we merge it?

[lyakh]

@lyakh Can we merge it?

@softwarecki sure, sorry, I was on holiday, which was why I suggested to remove the label without me. I was a bit concerned about using a specific error code to identify a "soft failure" in sys_mm_drv_unmap_page_wflush(), but it's a static ACE-specific function, so shouldn't be a problem. BTW, we could use "ace" somewhere in the names of such static functions to make it more obvious. E.g. ace_mm_drv_unmap_page_wflush()

[softwarecki]

@lyakh This error code is well described in the sys_mm_drv_unmap_page function documentation.

/**
 * @brief Remove mapping for one page of the provided virtual address
 *
 * This unmaps one page from the virtual address space.
 *
 * When this completes, the relevant translation table entries will be
 * updated as if no mapping was ever made for that memory page. No previous
 * context needs to be preserved. This function must update mapping in
 * all active translation tables.
 *
 * Behavior when providing unaligned address is undefined, this
 * is assumed to be page aligned.
 *
 * Implementations must invalidate translation caching as necessary.
 *
 * @param virt Page-aligned virtual address to un-map
 *
 * @retval 0 if successful
 * @retval -EINVAL if invalid arguments are provided
 * @retval -EFAULT if virtual address is not mapped
 */
int sys_mm_drv_unmap_page(void *virt);

In this driver the sys_mm_drv_unmap_page function just call the sys_mm_drv_unmap_page_wflush so it return a appropriate error code.