Am 20.05.21 um 17:09 schrieb Thomas Hellström:
Use fast wc memcpy for reading out of wc memory for TTM bo moves.
Cc: Dave Airlie <airlied@xxxxxxxxx>
Cc: Christian König <christian.koenig@xxxxxxx>
Cc: Daniel Vetter <daniel.vetter@xxxxxxxx>
Signed-off-by: Thomas Hellström <thomas.hellstrom@xxxxxxxxxxxxxxx>
Oh, yes I really wanted to have that in TTM for quite some time.
But I'm wondering if we shouldn't fix the memremap stuff first.
Christian.
---
drivers/gpu/drm/ttm/ttm_bo_util.c | 18 +++++++++++++++++-
1 file changed, 17 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/ttm/ttm_bo_util.c b/drivers/gpu/drm/ttm/ttm_bo_util.c
index bad9b16e96ba..919ee03f7eb3 100644
--- a/drivers/gpu/drm/ttm/ttm_bo_util.c
+++ b/drivers/gpu/drm/ttm/ttm_bo_util.c
@@ -31,6 +31,7 @@
#include <drm/ttm/ttm_bo_driver.h>
#include <drm/ttm/ttm_placement.h>
+#include <drm/drm_memcpy.h>
#include <drm/drm_vma_manager.h>
#include <linux/dma-buf-map.h>
#include <linux/io.h>
@@ -185,6 +186,7 @@ void ttm_move_memcpy(struct ttm_buffer_object *bo,
struct ttm_resource *old_mem = &bo->mem;
struct ttm_resource_manager *old_man = ttm_manager_type(bdev, old_mem->mem_type);
struct dma_buf_map old_map, new_map;
+ bool wc_memcpy;
pgoff_t i;
/* Single TTM move. NOP */
@@ -208,11 +210,25 @@ void ttm_move_memcpy(struct ttm_buffer_object *bo,
return;
}
+ wc_memcpy = ((!old_man->use_tt || bo->ttm->caching != ttm_cached) &&
+ drm_has_memcpy_from_wc());
+
+ /*
+ * We use some nasty aliasing for drm_memcpy_from_wc, but assuming
+ * that we can move to memremapping in the not too distant future,
+ * reduce the fragility for now with a build assert.
+ */
+ BUILD_BUG_ON(offsetof(typeof(old_map), vaddr) !=
+ offsetof(typeof(old_map), vaddr_iomem));
+
for (i = 0; i < new_mem->num_pages; ++i) {
new_iter->ops->kmap_local(new_iter, &new_map, i);
old_iter->ops->kmap_local(old_iter, &old_map, i);
- if (!old_map.is_iomem && !new_map.is_iomem) {
+ if (wc_memcpy) {
+ drm_memcpy_from_wc(new_map.vaddr, old_map.vaddr,
+ PAGE_SIZE);
+ } else if (!old_map.is_iomem && !new_map.is_iomem) {
memcpy(new_map.vaddr, old_map.vaddr, PAGE_SIZE);
} else if (!old_map.is_iomem) {
dma_buf_map_memcpy_to(&new_map, old_map.vaddr,
