ttm: add prime sharing support to TTM (v2)

This adds the ability for ttm common code to take an SG table
and use it as the backing for a slave TTM object.

The drivers can then populate their GTT tables using the SG object.

v2: make sure to setup VM for sg bos as well.

Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Jerome Glisse <jglisse@redhat.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

4 files changed, 18 insertions, 5 deletions

diff --git a/drivers/gpu/drm/nouveau/nouveau_bo.c b/drivers/gpu/drm/nouveau/nouveau_bo.c
index 12ce044f12f..81599d6e636 100644
--- a/drivers/gpu/drm/nouveau/nouveau_bo.c
+++ b/drivers/gpu/drm/nouveau/nouveau_bo.c
@@ -121,7 +121,7 @@ nouveau_bo_new(struct drm_device *dev, int size, int align,
 
 	ret = ttm_bo_init(&dev_priv->ttm.bdev, &nvbo->bo, size,
 			  ttm_bo_type_device, &nvbo->placement,
-			  align >> PAGE_SHIFT, 0, false, NULL, acc_size,
+			  align >> PAGE_SHIFT, 0, false, NULL, acc_size, NULL,
 			  nouveau_bo_del_ttm);
 	if (ret) {
 		/* ttm will call nouveau_bo_del_ttm if it fails.. */
diff --git a/drivers/gpu/drm/radeon/radeon_object.c b/drivers/gpu/drm/radeon/radeon_object.c
index df6a4dbd93f..1affbc954c5 100644
--- a/drivers/gpu/drm/radeon/radeon_object.c
+++ b/drivers/gpu/drm/radeon/radeon_object.c
@@ -155,7 +155,7 @@ retry:
 	mutex_lock(&rdev->vram_mutex);
 	r = ttm_bo_init(&rdev->mman.bdev, &bo->tbo, size, type,
 			&bo->placement, page_align, 0, !kernel, NULL,
-			acc_size, &radeon_ttm_bo_destroy);
+			acc_size, NULL, &radeon_ttm_bo_destroy);
 	mutex_unlock(&rdev->vram_mutex);
 	if (unlikely(r != 0)) {
 		if (r != -ERESTARTSYS) {
diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
index 1f5c67c579c..36792bd4da7 100644
--- a/drivers/gpu/drm/ttm/ttm_bo.c
+++ b/drivers/gpu/drm/ttm/ttm_bo.c
@@ -343,6 +343,16 @@ static int ttm_bo_add_ttm(struct ttm_buffer_object *bo, bool zero_alloc)
 		if (unlikely(bo->ttm == NULL))
 			ret = -ENOMEM;
 		break;
+	case ttm_bo_type_sg:
+		bo->ttm = bdev->driver->ttm_tt_create(bdev, bo->num_pages << PAGE_SHIFT,
+						      page_flags | TTM_PAGE_FLAG_SG,
+						      glob->dummy_read_page);
+		if (unlikely(bo->ttm == NULL)) {
+			ret = -ENOMEM;
+			break;
+		}
+		bo->ttm->sg = bo->sg;
+		break;
 	default:
 		pr_err("Illegal buffer object type\n");
 		ret = -EINVAL;
@@ -1169,6 +1179,7 @@ int ttm_bo_init(struct ttm_bo_device *bdev,
 		bool interruptible,
 		struct file *persistent_swap_storage,
 		size_t acc_size,
+		struct sg_table *sg,
 		void (*destroy) (struct ttm_buffer_object *))
 {
 	int ret = 0;
@@ -1223,6 +1234,7 @@ int ttm_bo_init(struct ttm_bo_device *bdev,
 	bo->seq_valid = false;
 	bo->persistent_swap_storage = persistent_swap_storage;
 	bo->acc_size = acc_size;
+	bo->sg = sg;
 	atomic_inc(&bo->glob->bo_count);
 
 	ret = ttm_bo_check_placement(bo, placement);
@@ -1233,7 +1245,8 @@ int ttm_bo_init(struct ttm_bo_device *bdev,
 	 * For ttm_bo_type_device buffers, allocate
 	 * address space from the device.
 	 */
-	if (bo->type == ttm_bo_type_device) {
+	if (bo->type == ttm_bo_type_device ||
+	    bo->type == ttm_bo_type_sg) {
 		ret = ttm_bo_setup_vm(bo);
 		if (ret)
 			goto out_err;
@@ -1312,7 +1325,7 @@ int ttm_bo_create(struct ttm_bo_device *bdev,
 
 	ret = ttm_bo_init(bdev, bo, size, type, placement, page_alignment,
 				buffer_start, interruptible,
-				persistent_swap_storage, acc_size, NULL);
+			  persistent_swap_storage, acc_size, NULL, NULL);
 	if (likely(ret == 0))
 		*p_bo = bo;
 
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_resource.c b/drivers/gpu/drm/vmwgfx/vmwgfx_resource.c
index a37abb581cb..22bf9a21ec7 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_resource.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_resource.c
@@ -1567,7 +1567,7 @@ int vmw_dmabuf_init(struct vmw_private *dev_priv,
 	ret = ttm_bo_init(bdev, &vmw_bo->base, size,
 			  ttm_bo_type_device, placement,
 			  0, 0, interruptible,
-			  NULL, acc_size, bo_free);
+			  NULL, acc_size, NULL, bo_free);
 	return ret;
 }