Commit 69a42990 authored by Boris Brezillon's avatar Boris Brezillon
Browse files

drm/panthor: Relax the constraints on the tiler chunk size 



The field used to store the chunk size if 12 bits wide, and the encoding
is chunk_size = chunk_header.chunk_size << 12, which gives us a
theoretical [4k:8M] range. This range is further limited by
implementation constraints, and all known implementations seem to
impose a [128k:8M] range, so do the same here.

We also relax the power-of-two constraint, which doesn't seem to
exist on v10. This will allow userspace to fine-tune initial/max
tiler memory on memory-constrained devices.

v4:
- Actually fix the range in the kerneldoc

v3:
- Add R-bs
- Fix valid range in the kerneldoc

v2:
- Turn the power-of-two constraint into a page-aligned constraint to allow
  fine-tune of the initial/max heap memory size
- Fix the panthor_heap_create() kerneldoc

Fixes: 9cca48fa ("drm/panthor: Add the heap logical block")
Signed-off-by: default avatarBoris Brezillon <boris.brezillon@collabora.com>
Reviewed-by: default avatarLiviu Dudau <liviu.dudau@arm.com>
Reviewed-by: default avatarSteven Price <steven.price@arm.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240502165158.1458959-4-boris.brezillon@collabora.com
parent e3193f0f

drivers/gpu/drm/panthor/panthor_heap.c

+4 −4
Original line number Diff line number Diff line
@@ -253,8 +253,8 @@ int panthor_heap_destroy(struct panthor_heap_pool *pool, u32 handle) 
 * @pool: Pool to instantiate the heap context from.

 * @initial_chunk_count: Number of chunk allocated at initialization time.

 * Must be at least 1.

 * @chunk_size: The size of each chunk. Must be a power of two between 256k

 * and 2M.

 * @chunk_size: The size of each chunk. Must be page-aligned and lie in the

 * [128k:8M] range.

 * @max_chunks: Maximum number of chunks that can be allocated.

 * @target_in_flight: Maximum number of in-flight render passes.

 * @heap_ctx_gpu_va: Pointer holding the GPU address of the allocated heap
@@ -284,8 +284,8 @@ int panthor_heap_create(struct panthor_heap_pool *pool, 
	if (initial_chunk_count > max_chunks)

		return -EINVAL;



	if (hweight32(chunk_size) != 1 ||

	    chunk_size < SZ_256K || chunk_size > SZ_2M)

	if (!IS_ALIGNED(chunk_size, PAGE_SIZE) ||

	    chunk_size < SZ_128K || chunk_size > SZ_8M)

		return -EINVAL;



	down_read(&pool->lock);

include/uapi/drm/panthor_drm.h

+5 −1
Original line number Diff line number Diff line
@@ -898,7 +898,11 @@ struct drm_panthor_tiler_heap_create { 
	/** @initial_chunk_count: Initial number of chunks to allocate. Must be at least one. */

	__u32 initial_chunk_count;



	/** @chunk_size: Chunk size. Must be a power of two at least 256KB large. */

	/**

	 * @chunk_size: Chunk size.

	 *

	 * Must be page-aligned and lie in the [128k:8M] range.

	 */

	__u32 chunk_size;



	/**