drm/nouveau: allocate GPFIFOs and fences coherently

Specify TTM_PL_FLAG_UNCACHED when allocating GPFIFOs and fences to
allow them to be safely accessed by the kernel without being synced
on non-coherent architectures.
Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drivers/gpu/drm/nouveau/nouveau_chan.c

@@ -102,7 +102,7 @@ nouveau_channel_prep(struct nouveau_drm *drm, struct nvif_device *device,
 	chan->drm = drm;
 
 	/* allocate memory for dma push buffer */
-	target = TTM_PL_FLAG_TT;
+	target = TTM_PL_FLAG_TT | TTM_PL_FLAG_UNCACHED;
 	if (nouveau_vram_pushbuf)
 		target = TTM_PL_FLAG_VRAM;
 

drivers/gpu/drm/nouveau/nv84_fence.c

@@ -246,8 +246,8 @@ nv84_fence_create(struct nouveau_drm *drm)
 
 	if (ret == 0)
 		ret = nouveau_bo_new(drm->dev, 16 * priv->base.contexts, 0,
-				     TTM_PL_FLAG_TT, 0, 0, NULL, NULL,
-				     &priv->bo_gart);
+				     TTM_PL_FLAG_TT | TTM_PL_FLAG_UNCACHED, 0,
+				     0, NULL, NULL, &priv->bo_gart);
 	if (ret == 0) {
 		ret = nouveau_bo_pin(priv->bo_gart, TTM_PL_FLAG_TT);
 		if (ret == 0) {