drm/ttm: remove TTM_MEMTYPE_FLAG_CMA

The original intention was to avoid CPU page table unmaps
when BOs move between the GTT and SYSTEM domain.

The problem is that this never correctly handled changes
in the caching attributes or backing pages.

Just drop this for now and simply unmap the CPU page
tables in all cases.
Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/378240/

drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c

@@ -93,7 +93,7 @@ static int amdgpu_init_mem_type(struct ttm_bo_device *bdev, uint32_t type,
 		man->func = &amdgpu_gtt_mgr_func;
 		man->available_caching = TTM_PL_MASK_CACHING;
 		man->default_caching = TTM_PL_FLAG_CACHED;
-		man->flags = TTM_MEMTYPE_FLAG_MAPPABLE | TTM_MEMTYPE_FLAG_CMA;
+		man->flags = TTM_MEMTYPE_FLAG_MAPPABLE;
 		break;
 	case TTM_PL_VRAM:
 		/* "On-card" video ram */
@@ -108,7 +108,7 @@ static int amdgpu_init_mem_type(struct ttm_bo_device *bdev, uint32_t type,
 	case AMDGPU_PL_OA:
 		/* On-chip GDS memory*/
 		man->func = &ttm_bo_manager_func;
-		man->flags = TTM_MEMTYPE_FLAG_FIXED | TTM_MEMTYPE_FLAG_CMA;
+		man->flags = TTM_MEMTYPE_FLAG_FIXED;
 		man->available_caching = TTM_PL_FLAG_UNCACHED;
 		man->default_caching = TTM_PL_FLAG_UNCACHED;
 		break;

drivers/gpu/drm/nouveau/nouveau_bo.c

@@ -695,8 +695,7 @@ nouveau_bo_init_mem_type(struct ttm_bo_device *bdev, uint32_t type,
 				TTM_PL_FLAG_WC;
 			man->default_caching = TTM_PL_FLAG_WC;
 		} else {
-			man->flags = TTM_MEMTYPE_FLAG_MAPPABLE |
-				     TTM_MEMTYPE_FLAG_CMA;
+			man->flags = TTM_MEMTYPE_FLAG_MAPPABLE;
 			man->available_caching = TTM_PL_MASK_CACHING;
 			man->default_caching = TTM_PL_FLAG_CACHED;
 		}

drivers/gpu/drm/radeon/radeon_ttm.c

@@ -84,7 +84,7 @@ static int radeon_init_mem_type(struct ttm_bo_device *bdev, uint32_t type,
 		man->func = &ttm_bo_manager_func;
 		man->available_caching = TTM_PL_MASK_CACHING;
 		man->default_caching = TTM_PL_FLAG_CACHED;
-		man->flags = TTM_MEMTYPE_FLAG_MAPPABLE | TTM_MEMTYPE_FLAG_CMA;
+		man->flags = TTM_MEMTYPE_FLAG_MAPPABLE;
 #if IS_ENABLED(CONFIG_AGP)
 		if (rdev->flags & RADEON_IS_AGP) {
 			if (!rdev->ddev->agp) {

drivers/gpu/drm/ttm/ttm_bo.c

@@ -272,20 +272,15 @@ static int ttm_bo_handle_move_mem(struct ttm_buffer_object *bo,
 				  struct ttm_operation_ctx *ctx)
 {
 	struct ttm_bo_device *bdev = bo->bdev;
-	bool old_is_pci = ttm_mem_reg_is_pci(bdev, &bo->mem);
-	bool new_is_pci = ttm_mem_reg_is_pci(bdev, mem);
 	struct ttm_mem_type_manager *old_man = &bdev->man[bo->mem.mem_type];
 	struct ttm_mem_type_manager *new_man = &bdev->man[mem->mem_type];
-	int ret = 0;
+	int ret;
 
-	if (old_is_pci || new_is_pci ||
-	    ((mem->placement & bo->mem.placement & TTM_PL_MASK_CACHING) == 0)) {
 	ret = ttm_mem_io_lock(old_man, true);
 	if (unlikely(ret != 0))
 		goto out_err;
 	ttm_bo_unmap_virtual_locked(bo);
 	ttm_mem_io_unlock(old_man);
-	}
 
 	/*
 	 * Create and bind a ttm if required.
@@ -1698,23 +1693,6 @@ EXPORT_SYMBOL(ttm_bo_device_init);
  * buffer object vm functions.
  */
 
-bool ttm_mem_reg_is_pci(struct ttm_bo_device *bdev, struct ttm_mem_reg *mem)
-{
-	struct ttm_mem_type_manager *man = &bdev->man[mem->mem_type];
-
-	if (!(man->flags & TTM_MEMTYPE_FLAG_FIXED)) {
-		if (mem->mem_type == TTM_PL_SYSTEM)
-			return false;
-
-		if (man->flags & TTM_MEMTYPE_FLAG_CMA)
-			return false;
-
-		if (mem->placement & TTM_PL_FLAG_CACHED)
-			return false;
-	}
-	return true;
-}
-
 void ttm_bo_unmap_virtual_locked(struct ttm_buffer_object *bo)
 {
 	struct ttm_bo_device *bdev = bo->bdev;

drivers/gpu/drm/vmwgfx/vmwgfx_ttm_buffer.c

@@ -762,7 +762,7 @@ static int vmw_init_mem_type(struct ttm_bo_device *bdev, uint32_t type,
 		 *  slots as well as the bo size.
 		 */
 		man->func = &vmw_gmrid_manager_func;
-		man->flags = TTM_MEMTYPE_FLAG_CMA | TTM_MEMTYPE_FLAG_MAPPABLE;
+		man->flags = TTM_MEMTYPE_FLAG_MAPPABLE;
 		man->available_caching = TTM_PL_FLAG_CACHED;
 		man->default_caching = TTM_PL_FLAG_CACHED;
 		break;

include/drm/ttm/ttm_bo_driver.h

@@ -47,7 +47,6 @@
 
 #define TTM_MEMTYPE_FLAG_FIXED         (1 << 0)	/* Fixed (on-card) PCI memory */
 #define TTM_MEMTYPE_FLAG_MAPPABLE      (1 << 1)	/* Memory mappable */
-#define TTM_MEMTYPE_FLAG_CMA           (1 << 3)	/* Can't map aperture */
 
 struct ttm_mem_type_manager;