drm/vc4: Optimize BRANCH_TO_SUBLIST validation.

We typically get bin_tiles_x * bin_tiles_y of these, so it makes sense
to do a tiny bit of up front work to make this easier (particularly,
avoid a divide, since those are terrible).  Saves about half a percent
of the CPU.

Signed-off-by: Eric Anholt <eric@anholt.net>

2 files changed, 12 insertions, 7 deletions

diff --git a/drivers/gpu/drm/vc4/vc4_drv.h b/drivers/gpu/drm/vc4/vc4_drv.h
index 57b889e072ef..6b3e07cf8443 100644
--- a/drivers/gpu/drm/vc4/vc4_drv.h
+++ b/drivers/gpu/drm/vc4/vc4_drv.h
@@ -234,7 +234,8 @@ struct vc4_exec_info {
 	bool found_wait_on_semaphore_packet;
 	uint8_t bin_tiles_x, bin_tiles_y;
 	uint32_t fb_width, fb_height;
-	uint32_t tile_alloc_init_block_size;
+	uint32_t tile_alloc_init_block_mask;
+	uint32_t tile_alloc_init_block_last;
 	struct drm_gem_cma_object *tile_alloc_bo;
 
 	/**
diff --git a/drivers/gpu/drm/vc4/vc4_validate.c b/drivers/gpu/drm/vc4/vc4_validate.c
index 7c6925cd7929..b1f88bb8ecaa 100644
--- a/drivers/gpu/drm/vc4/vc4_validate.c
+++ b/drivers/gpu/drm/vc4/vc4_validate.c
@@ -286,9 +286,8 @@ validate_branch_to_sublist(VALIDATE_ARGS)
 	}
 
 	offset = *(uint32_t *)(untrusted + 0);
-	if (offset % exec->tile_alloc_init_block_size ||
-	    offset / exec->tile_alloc_init_block_size >=
-	    exec->bin_tiles_x * exec->bin_tiles_y) {
+	if (offset & exec->tile_alloc_init_block_mask ||
+	    offset > exec->tile_alloc_init_block_last) {
 		DRM_ERROR("VC4_PACKET_BRANCH_TO_SUB_LIST must jump to initial "
 			  "tile allocation space.\n");
 		return -EINVAL;
@@ -496,6 +495,7 @@ validate_tile_binning_config(VALIDATE_ARGS)
 	struct drm_gem_cma_object *tile_state_data_array;
 	uint8_t flags;
 	uint32_t tile_allocation_size;
+	uint32_t tile_alloc_init_block_size;
 
 	if (!vc4_use_handle(exec, 0, VC4_MODE_TILE_ALLOC, &tile_allocation) ||
 	    !vc4_use_handle(exec, 1, VC4_MODE_TSDA, &tile_state_data_array))
@@ -547,15 +547,19 @@ validate_tile_binning_config(VALIDATE_ARGS)
 	*(uint32_t *)validated = tile_allocation->paddr;
 	exec->tile_alloc_bo = tile_allocation;
 
-	exec->tile_alloc_init_block_size = 1 << (5 + ((flags >> 5) & 3));
+	tile_alloc_init_block_size = 1 << (5 + ((flags >> 5) & 3));
 	if (exec->bin_tiles_x * exec->bin_tiles_y *
-	    exec->tile_alloc_init_block_size > tile_allocation_size) {
+	    tile_alloc_init_block_size > tile_allocation_size) {
 		DRM_ERROR("tile init exceeds tile alloc size (%d vs %d)\n",
 			  exec->bin_tiles_x * exec->bin_tiles_y *
-			  exec->tile_alloc_init_block_size,
+			  tile_alloc_init_block_size,
 			  tile_allocation_size);
 		return -EINVAL;
 	}
+	exec->tile_alloc_init_block_mask = tile_alloc_init_block_size - 1;
+	exec->tile_alloc_init_block_last = tile_alloc_init_block_size *
+		(exec->bin_tiles_x * exec->bin_tiles_y - 1);
+
 	if (*(uint32_t *)(untrusted + 8) != 0) {
 		DRM_ERROR("TSDA offset != 0 unsupported\n");
 		return -EINVAL;