diff --git a/Documentation/DocBook/drm.tmpl b/Documentation/DocBook/drm.tmpl
index 6c11d77c8d0225c512c1e4e6ecd35cfee0c86287..b26de523ab70ff492e40d9b956724a7a3d44c8c1 100644
--- a/Documentation/DocBook/drm.tmpl
+++ b/Documentation/DocBook/drm.tmpl
@@ -743,6 +743,10 @@ char *date;</synopsis>
These two operations are mandatory for GEM drivers that support DRM
PRIME.
</para>
+ <sect4>
+ <title>DRM PRIME Helper Functions Reference</title>
+!Pdrivers/gpu/drm/drm_prime.c PRIME Helpers
+ </sect4>
</sect3>
<sect3 id="drm-gem-objects-mapping">
<title>GEM Objects Mapping</title>
diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c
index 7f125738f44e78dc37439fe13b9bc0868e9d4baf..366910ddcfcb3cd96b33c2dcd9c1d122b01990b5 100644
--- a/drivers/gpu/drm/drm_prime.c
+++ b/drivers/gpu/drm/drm_prime.c
@@ -53,7 +53,8 @@
* Self-importing: if userspace is using PRIME as a replacement for flink
* then it will get a fd->handle request for a GEM object that it created.
* Drivers should detect this situation and return back the gem object
- * from the dma-buf private.
+ * from the dma-buf private. Prime will do this automatically for drivers that
+ * use the drm_gem_prime_{import,export} helpers.
*/
struct drm_prime_member {
@@ -62,6 +63,137 @@ struct drm_prime_member {
uint32_t handle;
};
+static struct sg_table *drm_gem_map_dma_buf(struct dma_buf_attachment *attach,
+ enum dma_data_direction dir)
+{
+ struct drm_gem_object *obj = attach->dmabuf->priv;
+ struct sg_table *sgt;
+
+ mutex_lock(&obj->dev->struct_mutex);
+
+ sgt = obj->dev->driver->gem_prime_get_sg_table(obj);
+
+ if (!IS_ERR_OR_NULL(sgt))
+ dma_map_sg(attach->dev, sgt->sgl, sgt->nents, dir);
+
+ mutex_unlock(&obj->dev->struct_mutex);
+ return sgt;
+}
+
+static void drm_gem_unmap_dma_buf(struct dma_buf_attachment *attach,
+ struct sg_table *sgt, enum dma_data_direction dir)
+{
+ dma_unmap_sg(attach->dev, sgt->sgl, sgt->nents, dir);
+ sg_free_table(sgt);
+ kfree(sgt);
+}
+
+static void drm_gem_dmabuf_release(struct dma_buf *dma_buf)
+{
+ struct drm_gem_object *obj = dma_buf->priv;
+
+ if (obj->export_dma_buf == dma_buf) {
+ /* drop the reference on the export fd holds */
+ obj->export_dma_buf = NULL;
+ drm_gem_object_unreference_unlocked(obj);
+ }
+}
+
+static void *drm_gem_dmabuf_vmap(struct dma_buf *dma_buf)
+{
+ struct drm_gem_object *obj = dma_buf->priv;
+ struct drm_device *dev = obj->dev;
+
+ return dev->driver->gem_prime_vmap(obj);
+}
+
+static void drm_gem_dmabuf_vunmap(struct dma_buf *dma_buf, void *vaddr)
+{
+ struct drm_gem_object *obj = dma_buf->priv;
+ struct drm_device *dev = obj->dev;
+
+ dev->driver->gem_prime_vunmap(obj, vaddr);
+}
+
+static void *drm_gem_dmabuf_kmap_atomic(struct dma_buf *dma_buf,
+ unsigned long page_num)
+{
+ return NULL;
+}
+
+static void drm_gem_dmabuf_kunmap_atomic(struct dma_buf *dma_buf,
+ unsigned long page_num, void *addr)
+{
+
+}
+static void *drm_gem_dmabuf_kmap(struct dma_buf *dma_buf,
+ unsigned long page_num)
+{
+ return NULL;
+}
+
+static void drm_gem_dmabuf_kunmap(struct dma_buf *dma_buf,
+ unsigned long page_num, void *addr)
+{
+
+}
+
+static int drm_gem_dmabuf_mmap(struct dma_buf *dma_buf,
+ struct vm_area_struct *vma)
+{
+ return -EINVAL;
+}
+
+static const struct dma_buf_ops drm_gem_prime_dmabuf_ops = {
+ .map_dma_buf = drm_gem_map_dma_buf,
+ .unmap_dma_buf = drm_gem_unmap_dma_buf,
+ .release = drm_gem_dmabuf_release,
+ .kmap = drm_gem_dmabuf_kmap,
+ .kmap_atomic = drm_gem_dmabuf_kmap_atomic,
+ .kunmap = drm_gem_dmabuf_kunmap,
+ .kunmap_atomic = drm_gem_dmabuf_kunmap_atomic,
+ .mmap = drm_gem_dmabuf_mmap,
+ .vmap = drm_gem_dmabuf_vmap,
+ .vunmap = drm_gem_dmabuf_vunmap,
+};
+
+/**
+ * DOC: PRIME Helpers
+ *
+ * Drivers can implement @gem_prime_export and @gem_prime_import in terms of
+ * simpler APIs by using the helper functions @drm_gem_prime_export and
+ * @drm_gem_prime_import. These functions implement dma-buf support in terms of
+ * five lower-level driver callbacks:
+ *
+ * Export callbacks:
+ *
+ * - @gem_prime_pin (optional): prepare a GEM object for exporting
+ *
+ * - @gem_prime_get_sg_table: provide a scatter/gather table of pinned pages
+ *
+ * - @gem_prime_vmap: vmap a buffer exported by your driver
+ *
+ * - @gem_prime_vunmap: vunmap a buffer exported by your driver
+ *
+ * Import callback:
+ *
+ * - @gem_prime_import_sg_table (import): produce a GEM object from another
+ * driver's scatter/gather table
+ */
+
+struct dma_buf *drm_gem_prime_export(struct drm_device *dev,
+ struct drm_gem_object *obj, int flags)
+{
+ if (dev->driver->gem_prime_pin) {
+ int ret = dev->driver->gem_prime_pin(obj);
+ if (ret)
+ return ERR_PTR(ret);
+ }
+ return dma_buf_export(obj, &drm_gem_prime_dmabuf_ops, obj->size,
+ 0600);
+}
+EXPORT_SYMBOL(drm_gem_prime_export);
+
int drm_gem_prime_handle_to_fd(struct drm_device *dev,
struct drm_file *file_priv, uint32_t handle, uint32_t flags,
int *prime_fd)
@@ -117,6 +249,58 @@ int drm_gem_prime_handle_to_fd(struct drm_device *dev,
}
EXPORT_SYMBOL(drm_gem_prime_handle_to_fd);
+struct drm_gem_object *drm_gem_prime_import(struct drm_device *dev,
+ struct dma_buf *dma_buf)
+{
+ struct dma_buf_attachment *attach;
+ struct sg_table *sgt;
+ struct drm_gem_object *obj;
+ int ret;
+
+ if (!dev->driver->gem_prime_import_sg_table)
+ return ERR_PTR(-EINVAL);
+
+ if (dma_buf->ops == &drm_gem_prime_dmabuf_ops) {
+ obj = dma_buf->priv;
+ if (obj->dev == dev) {
+ /*
+ * Importing dmabuf exported from out own gem increases
+ * refcount on gem itself instead of f_count of dmabuf.
+ */
+ drm_gem_object_reference(obj);
+ dma_buf_put(dma_buf);
+ return obj;
+ }
+ }
+
+ attach = dma_buf_attach(dma_buf, dev->dev);
+ if (IS_ERR(attach))
+ return ERR_PTR(PTR_ERR(attach));
+
+ sgt = dma_buf_map_attachment(attach, DMA_BIDIRECTIONAL);
+ if (IS_ERR_OR_NULL(sgt)) {
+ ret = PTR_ERR(sgt);
+ goto fail_detach;
+ }
+
+ obj = dev->driver->gem_prime_import_sg_table(dev, dma_buf->size, sgt);
+ if (IS_ERR(obj)) {
+ ret = PTR_ERR(obj);
+ goto fail_unmap;
+ }
+
+ obj->import_attach = attach;
+
+ return obj;
+
+fail_unmap:
+ dma_buf_unmap_attachment(attach, sgt, DMA_BIDIRECTIONAL);
+fail_detach:
+ dma_buf_detach(dma_buf, attach);
+ return ERR_PTR(ret);
+}
+EXPORT_SYMBOL(drm_gem_prime_import);
+
int drm_gem_prime_fd_to_handle(struct drm_device *dev,
struct drm_file *file_priv, int prime_fd, uint32_t *handle)
{
diff --git a/include/drm/drmP.h b/include/drm/drmP.h
index 3aaa50d64451f717c65473bfd365eeaa06a2c96e..2d94d7413d71cc02483bae57219007bb6f30dd28 100644
--- a/include/drm/drmP.h
+++ b/include/drm/drmP.h
@@ -930,6 +930,14 @@ struct drm_driver {
/* import dmabuf -> GEM */
struct drm_gem_object * (*gem_prime_import)(struct drm_device *dev,
struct dma_buf *dma_buf);
+ /* low-level interface used by drm_gem_prime_{import,export} */
+ int (*gem_prime_pin)(struct drm_gem_object *obj);
+ struct sg_table *(*gem_prime_get_sg_table)(struct drm_gem_object *obj);
+ struct drm_gem_object *(*gem_prime_import_sg_table)(
+ struct drm_device *dev, size_t size,
+ struct sg_table *sgt);
+ void *(*gem_prime_vmap)(struct drm_gem_object *obj);
+ void (*gem_prime_vunmap)(struct drm_gem_object *obj, void *vaddr);
/* vga arb irq handler */
void (*vgaarb_irq)(struct drm_device *dev, bool state);
@@ -1562,9 +1570,13 @@ extern int drm_clients_info(struct seq_file *m, void* data);
extern int drm_gem_name_info(struct seq_file *m, void *data);
+extern struct dma_buf *drm_gem_prime_export(struct drm_device *dev,
+ struct drm_gem_object *obj, int flags);
extern int drm_gem_prime_handle_to_fd(struct drm_device *dev,
struct drm_file *file_priv, uint32_t handle, uint32_t flags,
int *prime_fd);
+extern struct drm_gem_object *drm_gem_prime_import(struct drm_device *dev,
+ struct dma_buf *dma_buf);
extern int drm_gem_prime_fd_to_handle(struct drm_device *dev,
struct drm_file *file_priv, int prime_fd, uint32_t *handle);