drm/ttm: nuke caching placement flags

Changing the caching on the fly never really worked
flawlessly.

So stop this completely and just let drivers specific the
desired caching in the tt or bus object.
Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Michael J. Ruhl <michael.j.ruhl@intel.com>
Link: https://patchwork.freedesktop.org/patch/394256/

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

@@ -137,7 +137,7 @@ void amdgpu_bo_placement_from_domain(struct amdgpu_bo *abo, u32 domain)
 		places[c].fpfn = 0;
 		places[c].lpfn = 0;
 		places[c].mem_type = TTM_PL_VRAM;
-		places[c].flags = TTM_PL_FLAG_WC | TTM_PL_FLAG_UNCACHED;
+		places[c].flags = 0;
 
 		if (flags & AMDGPU_GEM_CREATE_CPU_ACCESS_REQUIRED)
 			places[c].lpfn = visible_pfn;
@@ -154,11 +154,6 @@ void amdgpu_bo_placement_from_domain(struct amdgpu_bo *abo, u32 domain)
 		places[c].lpfn = 0;
 		places[c].mem_type = TTM_PL_TT;
 		places[c].flags = 0;
-		if (flags & AMDGPU_GEM_CREATE_CPU_GTT_USWC)
-			places[c].flags |= TTM_PL_FLAG_WC |
-				TTM_PL_FLAG_UNCACHED;
-		else
-			places[c].flags |= TTM_PL_FLAG_CACHED;
 		c++;
 	}
 
@@ -167,11 +162,6 @@ void amdgpu_bo_placement_from_domain(struct amdgpu_bo *abo, u32 domain)
 		places[c].lpfn = 0;
 		places[c].mem_type = TTM_PL_SYSTEM;
 		places[c].flags = 0;
-		if (flags & AMDGPU_GEM_CREATE_CPU_GTT_USWC)
-			places[c].flags |= TTM_PL_FLAG_WC |
-				TTM_PL_FLAG_UNCACHED;
-		else
-			places[c].flags |= TTM_PL_FLAG_CACHED;
 		c++;
 	}
 
@@ -179,7 +169,7 @@ void amdgpu_bo_placement_from_domain(struct amdgpu_bo *abo, u32 domain)
 		places[c].fpfn = 0;
 		places[c].lpfn = 0;
 		places[c].mem_type = AMDGPU_PL_GDS;
-		places[c].flags = TTM_PL_FLAG_UNCACHED;
+		places[c].flags = 0;
 		c++;
 	}
 
@@ -187,7 +177,7 @@ void amdgpu_bo_placement_from_domain(struct amdgpu_bo *abo, u32 domain)
 		places[c].fpfn = 0;
 		places[c].lpfn = 0;
 		places[c].mem_type = AMDGPU_PL_GWS;
-		places[c].flags = TTM_PL_FLAG_UNCACHED;
+		places[c].flags = 0;
 		c++;
 	}
 
@@ -195,7 +185,7 @@ void amdgpu_bo_placement_from_domain(struct amdgpu_bo *abo, u32 domain)
 		places[c].fpfn = 0;
 		places[c].lpfn = 0;
 		places[c].mem_type = AMDGPU_PL_OA;
-		places[c].flags = TTM_PL_FLAG_UNCACHED;
+		places[c].flags = 0;
 		c++;
 	}
 
@@ -203,7 +193,7 @@ void amdgpu_bo_placement_from_domain(struct amdgpu_bo *abo, u32 domain)
 		places[c].fpfn = 0;
 		places[c].lpfn = 0;
 		places[c].mem_type = TTM_PL_SYSTEM;
-		places[c].flags = TTM_PL_MASK_CACHING;
+		places[c].flags = 0;
 		c++;
 	}
 

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

@@ -92,7 +92,7 @@ static void amdgpu_evict_flags(struct ttm_buffer_object *bo,
 		.fpfn = 0,
 		.lpfn = 0,
 		.mem_type = TTM_PL_SYSTEM,
-		.flags = TTM_PL_MASK_CACHING
+		.flags = 0
 	};
 
 	/* Don't handle scatter gather BOs */
@@ -538,19 +538,13 @@ static int amdgpu_move_vram_ram(struct ttm_buffer_object *bo, bool evict,
 	placements.fpfn = 0;
 	placements.lpfn = 0;
 	placements.mem_type = TTM_PL_TT;
-	placements.flags = TTM_PL_MASK_CACHING;
+	placements.flags = 0;
 	r = ttm_bo_mem_space(bo, &placement, &tmp_mem, ctx);
 	if (unlikely(r)) {
 		pr_err("Failed to find GTT space for blit from VRAM\n");
 		return r;
 	}
 
-	/* set caching flags */
-	r = ttm_tt_set_placement_caching(bo->ttm, tmp_mem.placement);
-	if (unlikely(r)) {
-		goto out_cleanup;
-	}
-
 	r = ttm_tt_populate(bo->bdev, bo->ttm, ctx);
 	if (unlikely(r))
 		goto out_cleanup;
@@ -599,7 +593,7 @@ static int amdgpu_move_ram_vram(struct ttm_buffer_object *bo, bool evict,
 	placements.fpfn = 0;
 	placements.lpfn = 0;
 	placements.mem_type = TTM_PL_TT;
-	placements.flags = TTM_PL_MASK_CACHING;
+	placements.flags = 0;
 	r = ttm_bo_mem_space(bo, &placement, &tmp_mem, ctx);
 	if (unlikely(r)) {
 		pr_err("Failed to find GTT space for blit to VRAM\n");

drivers/gpu/drm/drm_gem_vram_helper.c

@@ -147,15 +147,12 @@ static void drm_gem_vram_placement(struct drm_gem_vram_object *gbo,
 
 	if (pl_flag & DRM_GEM_VRAM_PL_FLAG_VRAM) {
 		gbo->placements[c].mem_type = TTM_PL_VRAM;
-		gbo->placements[c++].flags = TTM_PL_FLAG_WC |
-					     TTM_PL_FLAG_UNCACHED |
-					     invariant_flags;
+		gbo->placements[c++].flags = invariant_flags;
 	}
 
 	if (pl_flag & DRM_GEM_VRAM_PL_FLAG_SYSTEM || !c) {
 		gbo->placements[c].mem_type = TTM_PL_SYSTEM;
-		gbo->placements[c++].flags = TTM_PL_MASK_CACHING |
-					     invariant_flags;
+		gbo->placements[c++].flags = invariant_flags;
 	}
 
 	gbo->placement.num_placement = c;

drivers/gpu/drm/nouveau/nouveau_bo.c

@@ -343,37 +343,23 @@ nouveau_bo_new(struct nouveau_cli *cli, u64 size, int align,
 }
 
 static void
-set_placement_list(struct nouveau_drm *drm, struct ttm_place *pl, unsigned *n,
-		   uint32_t domain, uint32_t flags)
+set_placement_list(struct ttm_place *pl, unsigned *n, uint32_t domain)
 {
 	*n = 0;
 
 	if (domain & NOUVEAU_GEM_DOMAIN_VRAM) {
-		struct nvif_mmu *mmu = &drm->client.mmu;
-		const u8 type = mmu->type[drm->ttm.type_vram].type;
-
 		pl[*n].mem_type = TTM_PL_VRAM;
-		pl[*n].flags = flags & ~TTM_PL_FLAG_CACHED;
-
-		/* Some BARs do not support being ioremapped WC */
-		if (drm->client.device.info.family >= NV_DEVICE_INFO_V0_TESLA &&
-		    type & NVIF_MEM_UNCACHED)
-			pl[*n].flags &= ~TTM_PL_FLAG_WC;
-
+		pl[*n].flags = 0;
 		(*n)++;
 	}
 	if (domain & NOUVEAU_GEM_DOMAIN_GART) {
 		pl[*n].mem_type = TTM_PL_TT;
-		pl[*n].flags = flags;
-
-		if (drm->agp.bridge)
-			pl[*n].flags &= ~TTM_PL_FLAG_CACHED;
-
+		pl[*n].flags = 0;
 		(*n)++;
 	}
 	if (domain & NOUVEAU_GEM_DOMAIN_CPU) {
 		pl[*n].mem_type = TTM_PL_SYSTEM;
-		pl[(*n)++].flags = flags;
+		pl[(*n)++].flags = 0;
 	}
 }
 
@@ -415,18 +401,14 @@ void
 nouveau_bo_placement_set(struct nouveau_bo *nvbo, uint32_t domain,
 			 uint32_t busy)
 {
-	struct nouveau_drm *drm = nouveau_bdev(nvbo->bo.bdev);
 	struct ttm_placement *pl = &nvbo->placement;
-	uint32_t flags = nvbo->force_coherent ? TTM_PL_FLAG_UNCACHED :
-						TTM_PL_MASK_CACHING;
 
 	pl->placement = nvbo->placements;
-	set_placement_list(drm, nvbo->placements, &pl->num_placement,
-			   domain, flags);
+	set_placement_list(nvbo->placements, &pl->num_placement, domain);
 
 	pl->busy_placement = nvbo->busy_placements;
-	set_placement_list(drm, nvbo->busy_placements, &pl->num_busy_placement,
-			   domain | busy, flags);
+	set_placement_list(nvbo->busy_placements, &pl->num_busy_placement,
+			   domain | busy);
 
 	set_placement_range(nvbo, domain);
 }
@@ -888,7 +870,7 @@ nouveau_bo_move_flipd(struct ttm_buffer_object *bo, bool evict,
 		.fpfn = 0,
 		.lpfn = 0,
 		.mem_type = TTM_PL_TT,
-		.flags = TTM_PL_MASK_CACHING
+		.flags = 0
 	};
 	struct ttm_placement placement;
 	struct ttm_resource tmp_reg;
@@ -930,7 +912,7 @@ nouveau_bo_move_flips(struct ttm_buffer_object *bo, bool evict,
 		.fpfn = 0,
 		.lpfn = 0,
 		.mem_type = TTM_PL_TT,
-		.flags = TTM_PL_MASK_CACHING
+		.flags = 0
 	};
 	struct ttm_placement placement;
 	struct ttm_resource tmp_reg;

drivers/gpu/drm/qxl/qxl_object.c

@@ -64,21 +64,21 @@ void qxl_ttm_placement_from_domain(struct qxl_bo *qbo, u32 domain)
 	qbo->placement.busy_placement = qbo->placements;
 	if (domain == QXL_GEM_DOMAIN_VRAM) {
 		qbo->placements[c].mem_type = TTM_PL_VRAM;
-		qbo->placements[c++].flags = TTM_PL_FLAG_CACHED | pflag;
+		qbo->placements[c++].flags = pflag;
 	}
 	if (domain == QXL_GEM_DOMAIN_SURFACE) {
 		qbo->placements[c].mem_type = TTM_PL_PRIV;
-		qbo->placements[c++].flags = TTM_PL_FLAG_CACHED | pflag;
+		qbo->placements[c++].flags = pflag;
 		qbo->placements[c].mem_type = TTM_PL_VRAM;
-		qbo->placements[c++].flags = TTM_PL_FLAG_CACHED | pflag;
+		qbo->placements[c++].flags = pflag;
 	}
 	if (domain == QXL_GEM_DOMAIN_CPU) {
 		qbo->placements[c].mem_type = TTM_PL_SYSTEM;
-		qbo->placements[c++].flags = TTM_PL_MASK_CACHING | pflag;
+		qbo->placements[c++].flags = pflag;
 	}
 	if (!c) {
 		qbo->placements[c].mem_type = TTM_PL_SYSTEM;
-		qbo->placements[c++].flags = TTM_PL_MASK_CACHING;
+		qbo->placements[c++].flags = 0;
 	}
 	qbo->placement.num_placement = c;
 	qbo->placement.num_busy_placement = c;

drivers/gpu/drm/qxl/qxl_ttm.c

@@ -56,7 +56,7 @@ static void qxl_evict_flags(struct ttm_buffer_object *bo,
 		.fpfn = 0,
 		.lpfn = 0,
 		.mem_type = TTM_PL_SYSTEM,
-		.flags = TTM_PL_MASK_CACHING
+		.flags = 0
 	};
 
 	if (!qxl_ttm_bo_is_qxl_bo(bo)) {

drivers/gpu/drm/radeon/radeon_object.c

@@ -113,57 +113,29 @@ void radeon_ttm_placement_from_domain(struct radeon_bo *rbo, u32 domain)
 			rbo->placements[c].fpfn =
 				rbo->rdev->mc.visible_vram_size >> PAGE_SHIFT;
 			rbo->placements[c].mem_type = TTM_PL_VRAM;
-			rbo->placements[c++].flags = TTM_PL_FLAG_WC |
-						     TTM_PL_FLAG_UNCACHED;
+			rbo->placements[c++].flags = 0;
 		}
 
 		rbo->placements[c].fpfn = 0;
 		rbo->placements[c].mem_type = TTM_PL_VRAM;
-		rbo->placements[c++].flags = TTM_PL_FLAG_WC |
-					     TTM_PL_FLAG_UNCACHED;
+		rbo->placements[c++].flags = 0;
 	}
 
 	if (domain & RADEON_GEM_DOMAIN_GTT) {
-		if (rbo->flags & RADEON_GEM_GTT_UC) {
-			rbo->placements[c].fpfn = 0;
-			rbo->placements[c].mem_type = TTM_PL_TT;
-			rbo->placements[c++].flags = TTM_PL_FLAG_UNCACHED;
-
-		} else if ((rbo->flags & RADEON_GEM_GTT_WC) ||
-			   (rbo->rdev->flags & RADEON_IS_AGP)) {
-			rbo->placements[c].fpfn = 0;
-			rbo->placements[c].mem_type = TTM_PL_TT;
-			rbo->placements[c++].flags = TTM_PL_FLAG_WC |
-				TTM_PL_FLAG_UNCACHED;
-		} else {
-			rbo->placements[c].fpfn = 0;
-			rbo->placements[c].mem_type = TTM_PL_TT;
-			rbo->placements[c++].flags = TTM_PL_FLAG_CACHED;
-		}
+		rbo->placements[c].fpfn = 0;
+		rbo->placements[c].mem_type = TTM_PL_TT;
+		rbo->placements[c++].flags = 0;
 	}
 
 	if (domain & RADEON_GEM_DOMAIN_CPU) {
-		if (rbo->flags & RADEON_GEM_GTT_UC) {
-			rbo->placements[c].fpfn = 0;
-			rbo->placements[c].mem_type = TTM_PL_SYSTEM;
-			rbo->placements[c++].flags = TTM_PL_FLAG_UNCACHED;
-
-		} else if ((rbo->flags & RADEON_GEM_GTT_WC) ||
-		    rbo->rdev->flags & RADEON_IS_AGP) {
-			rbo->placements[c].fpfn = 0;
-			rbo->placements[c].mem_type = TTM_PL_SYSTEM;
-			rbo->placements[c++].flags = TTM_PL_FLAG_WC |
-				TTM_PL_FLAG_UNCACHED;
-		} else {
-			rbo->placements[c].fpfn = 0;
-			rbo->placements[c].mem_type = TTM_PL_SYSTEM;
-			rbo->placements[c++].flags = TTM_PL_FLAG_CACHED;
-		}
+		rbo->placements[c].fpfn = 0;
+		rbo->placements[c].mem_type = TTM_PL_SYSTEM;
+		rbo->placements[c++].flags = 0;
 	}
 	if (!c) {
 		rbo->placements[c].fpfn = 0;
 		rbo->placements[c].mem_type = TTM_PL_SYSTEM;
-		rbo->placements[c++].flags = TTM_PL_MASK_CACHING;
+		rbo->placements[c++].flags = 0;
 	}
 
 	rbo->placement.num_placement = c;

drivers/gpu/drm/radeon/radeon_ttm.c

@@ -89,7 +89,7 @@ static void radeon_evict_flags(struct ttm_buffer_object *bo,
 		.fpfn = 0,
 		.lpfn = 0,
 		.mem_type = TTM_PL_SYSTEM,
-		.flags = TTM_PL_MASK_CACHING
+		.flags = 0
 	};
 
 	struct radeon_bo *rbo;
@@ -225,17 +225,12 @@ static int radeon_move_vram_ram(struct ttm_buffer_object *bo,
 	placements.fpfn = 0;
 	placements.lpfn = 0;
 	placements.mem_type = TTM_PL_TT;
-	placements.flags = TTM_PL_MASK_CACHING;
+	placements.flags = 0;
 	r = ttm_bo_mem_space(bo, &placement, &tmp_mem, ctx);
 	if (unlikely(r)) {
 		return r;
 	}
 
-	r = ttm_tt_set_placement_caching(bo->ttm, tmp_mem.placement);
-	if (unlikely(r)) {
-		goto out_cleanup;
-	}
-
 	r = ttm_tt_populate(bo->bdev, bo->ttm, ctx);
 	if (unlikely(r)) {
 		goto out_cleanup;
@@ -275,7 +270,7 @@ static int radeon_move_ram_vram(struct ttm_buffer_object *bo,
 	placements.fpfn = 0;
 	placements.lpfn = 0;
 	placements.mem_type = TTM_PL_TT;
-	placements.flags = TTM_PL_MASK_CACHING;
+	placements.flags = 0;
 	r = ttm_bo_mem_space(bo, &placement, &tmp_mem, ctx);
 	if (unlikely(r)) {
 		return r;
@@ -389,12 +384,7 @@ static int radeon_ttm_io_mem_reserve(struct ttm_bo_device *bdev, struct ttm_reso
 		 * Alpha: use bus.addr to hold the ioremap() return,
 		 * so we can modify bus.base below.
 		 */
-		if (mem->placement & TTM_PL_FLAG_WC)
-			mem->bus.addr =
-				ioremap_wc(mem->bus.offset, bus_size);
-		else
-			mem->bus.addr =
-				ioremap(mem->bus.offset, bus_size);
+		mem->bus.addr = ioremap_wc(mem->bus.offset, bus_size);
 		if (!mem->bus.addr)
 			return -ENOMEM;
 

drivers/gpu/drm/ttm/ttm_agp_backend.c

@@ -54,7 +54,7 @@ int ttm_agp_bind(struct ttm_tt *ttm, struct ttm_resource *bo_mem)
 	struct page *dummy_read_page = ttm_bo_glob.dummy_read_page;
 	struct drm_mm_node *node = bo_mem->mm_node;
 	struct agp_memory *mem;
-	int ret, cached = (bo_mem->placement & TTM_PL_FLAG_CACHED);
+	int ret, cached = ttm->caching == ttm_cached;
 	unsigned i;
 
 	if (agp_be->mem)

drivers/gpu/drm/ttm/ttm_bo.c

@@ -252,10 +252,6 @@ static int ttm_bo_handle_move_mem(struct ttm_buffer_object *bo,
 		if (ret)
 			goto out_err;
 
-		ret = ttm_tt_set_placement_caching(bo->ttm, mem->placement);
-		if (ret)
-			goto out_err;
-
 		if (mem->mem_type != TTM_PL_SYSTEM) {
 			ret = ttm_tt_populate(bdev, bo->ttm, ctx);
 			if (ret)
@@ -843,29 +839,6 @@ static int ttm_bo_mem_force_space(struct ttm_buffer_object *bo,
 	return ttm_bo_add_move_fence(bo, man, mem, ctx->no_wait_gpu);
 }
 
-static uint32_t ttm_bo_select_caching(struct ttm_resource_manager *man,
-				      uint32_t cur_placement,
-				      uint32_t proposed_placement)
-{
-	uint32_t caching = proposed_placement & TTM_PL_MASK_CACHING;
-	uint32_t result = proposed_placement & ~TTM_PL_MASK_CACHING;
-
-	/**
-	 * Keep current caching if possible.
-	 */
-
-	if ((cur_placement & caching) != 0)
-		result |= (cur_placement & caching);
-	else if ((TTM_PL_FLAG_CACHED & caching) != 0)
-		result |= TTM_PL_FLAG_CACHED;
-	else if ((TTM_PL_FLAG_WC & caching) != 0)
-		result |= TTM_PL_FLAG_WC;
-	else if ((TTM_PL_FLAG_UNCACHED & caching) != 0)
-		result |= TTM_PL_FLAG_UNCACHED;
-
-	return result;
-}
-
 /**
  * ttm_bo_mem_placement - check if placement is compatible
  * @bo: BO to find memory for
@@ -884,18 +857,13 @@ static int ttm_bo_mem_placement(struct ttm_buffer_object *bo,
 {
 	struct ttm_bo_device *bdev = bo->bdev;
 	struct ttm_resource_manager *man;
-	uint32_t cur_flags = 0;
 
 	man = ttm_manager_type(bdev, place->mem_type);
 	if (!man || !ttm_resource_manager_used(man))
 		return -EBUSY;
 
-	cur_flags = ttm_bo_select_caching(man, bo->mem.placement,
-					  place->flags);
-	cur_flags |= place->flags & ~TTM_PL_MASK_CACHING;
-
 	mem->mem_type = place->mem_type;
-	mem->placement = cur_flags;
+	mem->placement = place->flags;
 
 	spin_lock(&ttm_bo_glob.lru_lock);
 	ttm_bo_del_from_lru(bo);
@@ -1028,8 +996,7 @@ static bool ttm_bo_places_compat(const struct ttm_place *places,
 			continue;
 
 		*new_flags = heap->flags;
-		if ((*new_flags & mem->placement & TTM_PL_MASK_CACHING) &&
-		    (mem->mem_type == heap->mem_type) &&
+		if ((mem->mem_type == heap->mem_type) &&
 		    (!(*new_flags & TTM_PL_FLAG_CONTIGUOUS) ||
 		     (mem->placement & TTM_PL_FLAG_CONTIGUOUS)))
 			return true;
@@ -1083,9 +1050,6 @@ int ttm_bo_validate(struct ttm_buffer_object *bo,
 		ret = ttm_bo_move_buffer(bo, placement, ctx);
 		if (ret)
 			return ret;
-	} else {
-		bo->mem.placement &= TTM_PL_MASK_CACHING;
-		bo->mem.placement |= new_flags & ~TTM_PL_MASK_CACHING;
 	}
 	/*
 	 * We might need to add a TTM.
@@ -1153,7 +1117,7 @@ int ttm_bo_init_reserved(struct ttm_bo_device *bdev,
 	bo->mem.bus.offset = 0;
 	bo->mem.bus.addr = NULL;
 	bo->moving = NULL;
-	bo->mem.placement = TTM_PL_FLAG_CACHED;
+	bo->mem.placement = 0;
 	bo->acc_size = acc_size;
 	bo->pin_count = 0;
 	bo->sg = sg;
@@ -1484,7 +1448,7 @@ int ttm_bo_swapout(struct ttm_operation_ctx *ctx)
 
 		evict_mem = bo->mem;
 		evict_mem.mm_node = NULL;
-		evict_mem.placement = TTM_PL_MASK_CACHING;
+		evict_mem.placement = 0;
 		evict_mem.mem_type = TTM_PL_SYSTEM;
 
 		ret = ttm_bo_handle_move_mem(bo, &evict_mem, true, &ctx);

drivers/gpu/drm/ttm/ttm_bo_util.c

@@ -72,10 +72,6 @@ int ttm_bo_move_ttm(struct ttm_buffer_object *bo,
 		old_mem->mem_type = TTM_PL_SYSTEM;
 	}
 
-	ret = ttm_tt_set_placement_caching(ttm, new_mem->placement);
-	if (unlikely(ret != 0))
-		return ret;
-
 	if (new_mem->mem_type != TTM_PL_SYSTEM) {
 
 		ret = ttm_tt_populate(bo->bdev, ttm, ctx);
@@ -135,7 +131,7 @@ static int ttm_resource_ioremap(struct ttm_bo_device *bdev,
 	} else {
 		size_t bus_size = (size_t)mem->num_pages << PAGE_SHIFT;
 
-		if (mem->placement & TTM_PL_FLAG_WC)
+		if (mem->bus.caching == ttm_write_combined)
 			addr = ioremap_wc(mem->bus.offset, bus_size);
 		else
 			addr = ioremap(mem->bus.offset, bus_size);
@@ -427,7 +423,7 @@ static int ttm_bo_ioremap(struct ttm_buffer_object *bo,
 		map->virtual = (void *)(((u8 *)bo->mem.bus.addr) + offset);
 	} else {
 		map->bo_kmap_type = ttm_bo_map_iomap;
-		if (mem->placement & TTM_PL_FLAG_WC)
+		if (mem->bus.caching == ttm_write_combined)
 			map->virtual = ioremap_wc(bo->mem.bus.offset + offset,
 						  size);
 		else
@@ -457,7 +453,7 @@ static int ttm_bo_kmap_ttm(struct ttm_buffer_object *bo,
 	if (ret)
 		return ret;
 
-	if (num_pages == 1 && (mem->placement & TTM_PL_FLAG_CACHED)) {
+	if (num_pages == 1 && ttm->caching == ttm_cached) {
 		/*
 		 * We're mapping a single page, and the desired
 		 * page protection is consistent with the bo.

drivers/gpu/drm/ttm/ttm_tt.c

@@ -114,35 +114,6 @@ static int ttm_sg_tt_alloc_page_directory(struct ttm_dma_tt *ttm)
 	return 0;
 }
 
-static int ttm_tt_set_caching(struct ttm_tt *ttm, enum ttm_caching caching)
-{
-	if (ttm->caching == caching)
-		return 0;
-
-	/* Can't change the caching state after TT is populated */
-	if (WARN_ON_ONCE(ttm_tt_is_populated(ttm)))
-		return -EINVAL;
-
-	ttm->caching = caching;
-
-	return 0;
-}
-
-int ttm_tt_set_placement_caching(struct ttm_tt *ttm, uint32_t placement)
-{
-	enum ttm_caching state;
-
-	if (placement & TTM_PL_FLAG_WC)
-		state = ttm_write_combined;
-	else if (placement & TTM_PL_FLAG_UNCACHED)
-		state = ttm_uncached;
-	else
-		state = ttm_cached;
-
-	return ttm_tt_set_caching(ttm, state);
-}
-EXPORT_SYMBOL(ttm_tt_set_placement_caching);
-
 void ttm_tt_destroy_common(struct ttm_bo_device *bdev, struct ttm_tt *ttm)
 {
 	ttm_tt_unpopulate(bdev, ttm);

drivers/gpu/drm/vmwgfx/vmwgfx_ttm_buffer.c

@@ -34,28 +34,28 @@ static const struct ttm_place vram_placement_flags = {
 	.fpfn = 0,
 	.lpfn = 0,
 	.mem_type = TTM_PL_VRAM,
-	.flags = TTM_PL_FLAG_CACHED
+	.flags = 0
 };
 
 static const struct ttm_place sys_placement_flags = {
 	.fpfn = 0,
 	.lpfn = 0,
 	.mem_type = TTM_PL_SYSTEM,
-	.flags = TTM_PL_FLAG_CACHED
+	.flags = 0
 };
 
 static const struct ttm_place gmr_placement_flags = {
 	.fpfn = 0,
 	.lpfn = 0,
 	.mem_type = VMW_PL_GMR,
-	.flags = TTM_PL_FLAG_CACHED
+	.flags = 0
 };
 
 static const struct ttm_place mob_placement_flags = {
 	.fpfn = 0,
 	.lpfn = 0,
 	.mem_type = VMW_PL_MOB,
-	.flags = TTM_PL_FLAG_CACHED
+	.flags = 0
 };
 
 struct ttm_placement vmw_vram_placement = {
@@ -70,12 +70,12 @@ static const struct ttm_place vram_gmr_placement_flags[] = {
 		.fpfn = 0,
 		.lpfn = 0,
 		.mem_type = TTM_PL_VRAM,
-		.flags = TTM_PL_FLAG_CACHED
+		.flags = 0
 	}, {
 		.fpfn = 0,
 		.lpfn = 0,
 		.mem_type = VMW_PL_GMR,
-		.flags = TTM_PL_FLAG_CACHED
+		.flags = 0
 	}
 };
 
@@ -84,12 +84,12 @@ static const struct ttm_place gmr_vram_placement_flags[] = {
 		.fpfn = 0,
 		.lpfn = 0,
 		.mem_type = VMW_PL_GMR,
-		.flags = TTM_PL_FLAG_CACHED
+		.flags = 0
 	}, {
 		.fpfn = 0,
 		.lpfn = 0,
 		.mem_type = TTM_PL_VRAM,
-		.flags = TTM_PL_FLAG_CACHED
+		.flags = 0
 	}
 };
 
@@ -119,22 +119,22 @@ static const struct ttm_place evictable_placement_flags[] = {
 		.fpfn = 0,
 		.lpfn = 0,
 		.mem_type = TTM_PL_SYSTEM,
-		.flags = TTM_PL_FLAG_CACHED
+		.flags = 0
 	}, {
 		.fpfn = 0,
 		.lpfn = 0,
 		.mem_type = TTM_PL_VRAM,
-		.flags = TTM_PL_FLAG_CACHED
+		.flags = 0
 	}, {
 		.fpfn = 0,
 		.lpfn = 0,
 		.mem_type = VMW_PL_GMR,
-		.flags = TTM_PL_FLAG_CACHED
+		.flags = 0
 	}, {
 		.fpfn = 0,
 		.lpfn = 0,
 		.mem_type = VMW_PL_MOB,
-		.flags = TTM_PL_FLAG_CACHED
+		.flags = 0
 	}
 };
 
@@ -143,17 +143,17 @@ static const struct ttm_place nonfixed_placement_flags[] = {
 		.fpfn = 0,
 		.lpfn = 0,
 		.mem_type = TTM_PL_SYSTEM,
-		.flags = TTM_PL_FLAG_CACHED
+		.flags = 0
 	}, {
 		.fpfn = 0,
 		.lpfn = 0,
 		.mem_type = VMW_PL_GMR,
-		.flags = TTM_PL_FLAG_CACHED
+		.flags = 0
 	}, {
 		.fpfn = 0,
 		.lpfn = 0,
 		.mem_type = VMW_PL_MOB,
-		.flags = TTM_PL_FLAG_CACHED
+		.flags = 0
 	}
 };
 

include/drm/ttm/ttm_placement.h

@@ -43,27 +43,13 @@
 #define TTM_PL_PRIV             3
 
 /*
- * Other flags that affects data placement.
- * TTM_PL_FLAG_CACHED indicates cache-coherent mappings
- * if available.
- * TTM_PL_FLAG_SHARED means that another application may
- * reference the buffer.
- * TTM_PL_FLAG_NO_EVICT means that the buffer may never
- * be evicted to make room for other buffers.
  * TTM_PL_FLAG_TOPDOWN requests to be placed from the
  * top of the memory area, instead of the bottom.
  */
 
-#define TTM_PL_FLAG_CACHED      (1 << 16)
-#define TTM_PL_FLAG_UNCACHED    (1 << 17)
-#define TTM_PL_FLAG_WC          (1 << 18)
 #define TTM_PL_FLAG_CONTIGUOUS  (1 << 19)
 #define TTM_PL_FLAG_TOPDOWN     (1 << 22)
 
-#define TTM_PL_MASK_CACHING     (TTM_PL_FLAG_CACHED | \
-				 TTM_PL_FLAG_UNCACHED | \
-				 TTM_PL_FLAG_WC)
-
 /**
  * struct ttm_place
  *

include/drm/ttm/ttm_tt.h

@@ -164,21 +164,6 @@ void ttm_tt_destroy_common(struct ttm_bo_device *bdev, struct ttm_tt *ttm);
  * Swap in a previously swap out ttm_tt.
  */
 int ttm_tt_swapin(struct ttm_tt *ttm);
-
-/**
- * ttm_tt_set_placement_caching:
- *
- * @ttm A struct ttm_tt the backing pages of which will change caching policy.
- * @placement: Flag indicating the desired caching policy.
- *
- * This function will change caching policy of any default kernel mappings of
- * the pages backing @ttm. If changing from cached to uncached or
- * write-combined,
- * all CPU caches will first be flushed to make sure the data of the pages
- * hit RAM. This function may be very costly as it involves global TLB
- * and cache flushes and potential page splitting / combining.
- */
-int ttm_tt_set_placement_caching(struct ttm_tt *ttm, uint32_t placement);
 int ttm_tt_swapout(struct ttm_bo_device *bdev, struct ttm_tt *ttm);
 
 /**