[PATCH v4 02/13] drm/gem: Create infrastructure for GEM vmap_local

Thomas Zimmermann
2021-01-08T09:43:29Z

This patch adds vmap_local and vunmap_local to struct drm_gem_object_funcs;
including the PRIME helpers to connect with dma-buf's related interfaces.

Besides the generic DRM core, this will become relevant for fbdev emulation
with virtio, so we update it as well.

v4:
	* update documentation (Daniel)

Signed-off-by: Thomas Zimmermann <tzimmermann at suse.de>
Reviewed-by: Daniel Vetter <daniel.vetter at ffwll.ch>
---
 drivers/gpu/drm/drm_gem.c              | 28 ++++++++++++++++++
 drivers/gpu/drm/drm_internal.h         |  2 ++
 drivers/gpu/drm/drm_prime.c            | 39 ++++++++++++++++++++++++++
 drivers/gpu/drm/virtio/virtgpu_prime.c |  2 ++
 include/drm/drm_gem.h                  | 21 ++++++++++++++
 include/drm/drm_prime.h                |  2 ++
 6 files changed, 94 insertions(+)

diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c
index 92f89cee213e..6e131d9bb7bd 100644
--- a/drivers/gpu/drm/drm_gem.c
+++ b/drivers/gpu/drm/drm_gem.c
@@ -1234,6 +1234,34 @@ void drm_gem_vunmap(struct drm_gem_object *obj, struct
dma_buf_map *map)
 	dma_buf_map_clear(map);
 }

+int drm_gem_vmap_local(struct drm_gem_object *obj, struct dma_buf_map *map)
+{
+	int ret;
+
+	if (!obj->funcs->vmap_local)
+		return -EOPNOTSUPP;
+
+	ret = obj->funcs->vmap_local(obj, map);
+	if (ret)
+		return ret;
+	else if (dma_buf_map_is_null(map))
+		return -ENOMEM;
+
+	return 0;
+}
+
+void drm_gem_vunmap_local(struct drm_gem_object *obj, struct dma_buf_map *map)
+{
+	if (dma_buf_map_is_null(map))
+		return;
+
+	if (obj->funcs->vunmap_local)
+		obj->funcs->vunmap_local(obj, map);
+
+	/* Always set the mapping to NULL. Callers may rely on this. */
+	dma_buf_map_clear(map);
+}
+
 /**
  * drm_gem_lock_reservations - Sets up the ww context and acquires
  * the lock on an array of GEM objects.
diff --git a/drivers/gpu/drm/drm_internal.h b/drivers/gpu/drm/drm_internal.h
index 81d386b5b92a..b0bf6aba763a 100644
--- a/drivers/gpu/drm/drm_internal.h
+++ b/drivers/gpu/drm/drm_internal.h
@@ -190,6 +190,8 @@ int drm_gem_pin(struct drm_gem_object *obj);
 void drm_gem_unpin(struct drm_gem_object *obj);
 int drm_gem_vmap(struct drm_gem_object *obj, struct dma_buf_map *map);
 void drm_gem_vunmap(struct drm_gem_object *obj, struct dma_buf_map *map);
+int drm_gem_vmap_local(struct drm_gem_object *obj, struct dma_buf_map *map);
+void drm_gem_vunmap_local(struct drm_gem_object *obj, struct dma_buf_map *map);

 /* drm_debugfs.c drm_debugfs_crc.c */
 #if defined(CONFIG_DEBUG_FS)
diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c
index 683aa29ecd3b..633edea76985 100644
--- a/drivers/gpu/drm/drm_prime.c
+++ b/drivers/gpu/drm/drm_prime.c
@@ -695,6 +695,43 @@ void drm_gem_dmabuf_vunmap(struct dma_buf *dma_buf, struct
dma_buf_map *map)
 }
 EXPORT_SYMBOL(drm_gem_dmabuf_vunmap);

+/**
+ * drm_gem_dmabuf_vmap_local - dma_buf vmap_local implementation for GEM
+ * @dma_buf: buffer to be mapped
+ * @map: the virtual address of the buffer
+ *
+ * Sets up a kernel virtual mapping. This can be used as the
&dma_buf_ops.vmap_local
+ * callback. Calls into &drm_gem_object_funcs.vmap_local for device
specific handling.
+ * The kernel virtual address is returned in map.
+ *
+ * Returns:
+ * 0 on success or a negative errno code otherwise.
+ */
+int drm_gem_dmabuf_vmap_local(struct dma_buf *dma_buf, struct dma_buf_map *map)
+{
+	struct drm_gem_object *obj = dma_buf->priv;
+
+	return drm_gem_vmap_local(obj, map);
+}
+EXPORT_SYMBOL(drm_gem_dmabuf_vmap_local);
+
+/**
+ * drm_gem_dmabuf_vunmap_local - dma_buf vunmap_local implementation for GEM
+ * @dma_buf: buffer to be unmapped
+ * @map: the virtual address of the buffer
+ *
+ * Releases a kernel virtual mapping. This can be used as the
+ * &dma_buf_ops.vunmap_local callback. Calls into
&drm_gem_object_funcs.vunmap_local
+ * for device specific handling.
+ */
+void drm_gem_dmabuf_vunmap_local(struct dma_buf *dma_buf, struct dma_buf_map
*map)
+{
+	struct drm_gem_object *obj = dma_buf->priv;
+
+	drm_gem_vunmap_local(obj, map);
+}
+EXPORT_SYMBOL(drm_gem_dmabuf_vunmap_local);
+
 /**
  * drm_gem_prime_mmap - PRIME mmap function for GEM drivers
  * @obj: GEM object
@@ -787,6 +824,8 @@ static const struct dma_buf_ops drm_gem_prime_dmabuf_ops =
{
 	.mmap = drm_gem_dmabuf_mmap,
 	.vmap = drm_gem_dmabuf_vmap,
 	.vunmap = drm_gem_dmabuf_vunmap,
+	.vmap_local = drm_gem_dmabuf_vmap_local,
+	.vunmap_local = drm_gem_dmabuf_vunmap_local,
 };

 /**
diff --git a/drivers/gpu/drm/virtio/virtgpu_prime.c
b/drivers/gpu/drm/virtio/virtgpu_prime.c
index 807a27a16365..fea11a53d8fc 100644
--- a/drivers/gpu/drm/virtio/virtgpu_prime.c
+++ b/drivers/gpu/drm/virtio/virtgpu_prime.c
@@ -54,6 +54,8 @@ static const struct virtio_dma_buf_ops virtgpu_dmabuf_ops =  {
 		.mmap = drm_gem_dmabuf_mmap,
 		.vmap = drm_gem_dmabuf_vmap,
 		.vunmap = drm_gem_dmabuf_vunmap,
+		.vmap = drm_gem_dmabuf_vmap_local,
+		.vunmap = drm_gem_dmabuf_vunmap_local,
 	},
 	.device_attach = drm_gem_map_attach,
 	.get_uuid = virtgpu_virtio_get_uuid,
diff --git a/include/drm/drm_gem.h b/include/drm/drm_gem.h
index 5e6daa1c982f..1b4425dd1596 100644
--- a/include/drm/drm_gem.h
+++ b/include/drm/drm_gem.h
@@ -151,6 +151,27 @@ struct drm_gem_object_funcs {
 	 */
 	void (*vunmap)(struct drm_gem_object *obj, struct dma_buf_map *map);

+	/**
+	 * @vmap_local:
+	 *
+	 * Returns a virtual address for the buffer. Used by the
+	 * drm_gem_dmabuf_vmap_local() helper. Callers will hold
&drm_gem_object.resv
+	 * already and only release it after @vunmap_local has been called.
+	 *
+	 * This callback is optional.
+	 */
+	int (*vmap_local)(struct drm_gem_object *obj, struct dma_buf_map *map);
+
+	/**
+	 * @vunmap_local:
+	 *
+	 * Releases the address previously returned by @vmap. Used by the
+	 * drm_gem_dmabuf_vunmap_local() helper.
+	 *
+	 * This callback is optional.
+	 */
+	void (*vunmap_local)(struct drm_gem_object *obj, struct dma_buf_map *map);
+
 	/**
 	 * @mmap:
 	 *
diff --git a/include/drm/drm_prime.h b/include/drm/drm_prime.h
index 54f2c58305d2..fd2aef6966ef 100644
--- a/include/drm/drm_prime.h
+++ b/include/drm/drm_prime.h
@@ -85,6 +85,8 @@ void drm_gem_unmap_dma_buf(struct dma_buf_attachment *attach,
 			   enum dma_data_direction dir);
 int drm_gem_dmabuf_vmap(struct dma_buf *dma_buf, struct dma_buf_map *map);
 void drm_gem_dmabuf_vunmap(struct dma_buf *dma_buf, struct dma_buf_map *map);
+int drm_gem_dmabuf_vmap_local(struct dma_buf *dma_buf, struct dma_buf_map
*map);
+void drm_gem_dmabuf_vunmap_local(struct dma_buf *dma_buf, struct dma_buf_map
*map);

 int drm_gem_prime_mmap(struct drm_gem_object *obj, struct vm_area_struct *vma);
 int drm_gem_dmabuf_mmap(struct dma_buf *dma_buf, struct vm_area_struct *vma);
--
2.29.2