[RFC PATCHv2 2/3] drm/prime: Introduce drm_gem_prime_import_platform

[Laura Abbott <labbott@redhat.com>]

The existing drm_gem_prime_import function uses the underlying
struct device of a drm_device for attaching to a dma_buf. Some drivers
(notably vgem) may not have an underlying device structure. Offer
an alternate function to attach using a platform device associated
with drm_device.

Signed-off-by: Laura Abbott <labbott@redhat.com>
---
New approach for v2
---
 drivers/gpu/drm/drm_prime.c | 23 ++++++++++++++++++++---
 include/drm/drmP.h          |  5 +++++
 2 files changed, 25 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c
index 25aa455..5486248 100644
--- a/drivers/gpu/drm/drm_prime.c
+++ b/drivers/gpu/drm/drm_prime.c
@@ -601,8 +601,9 @@ EXPORT_SYMBOL(drm_gem_prime_handle_to_fd);
  * This is the implementation of the gem_prime_import functions for GEM drivers
  * using the PRIME helpers.
  */
-struct drm_gem_object *drm_gem_prime_import(struct drm_device *dev,
-					    struct dma_buf *dma_buf)
+static struct drm_gem_object *__drm_gem_prime_import(struct drm_device *dev,
+					    struct dma_buf *dma_buf,
+					    struct device *attach_dev)
 {
 	struct dma_buf_attachment *attach;
 	struct sg_table *sgt;
@@ -624,7 +625,7 @@ struct drm_gem_object *drm_gem_prime_import(struct drm_device *dev,
 	if (!dev->driver->gem_prime_import_sg_table)
 		return ERR_PTR(-EINVAL);
 
-	attach = dma_buf_attach(dma_buf, dev->dev);
+	attach = dma_buf_attach(dma_buf, attach_dev);
 	if (IS_ERR(attach))
 		return ERR_CAST(attach);
 
@@ -654,8 +655,24 @@ struct drm_gem_object *drm_gem_prime_import(struct drm_device *dev,
 
 	return ERR_PTR(ret);
 }
+
+struct drm_gem_object *drm_gem_prime_import(struct drm_device *dev,
+					    struct dma_buf *dma_buf)
+{
+	return __drm_gem_prime_import(dev, dma_buf, dev->dev);
+}
 EXPORT_SYMBOL(drm_gem_prime_import);
 
+struct drm_gem_object *drm_gem_prime_import_platform(struct drm_device *dev,
+					    struct dma_buf *dma_buf)
+{
+	if (WARN_ON_ONCE(!dev->platformdev))
+		return NULL;
+
+	return __drm_gem_prime_import(dev, dma_buf, &dev->platformdev->dev);
+}
+EXPORT_SYMBOL(drm_gem_prime_import_platform);
+
 /**
  * drm_gem_prime_fd_to_handle - PRIME import function for GEM drivers
  * @dev: dev to export the buffer from
diff --git a/include/drm/drmP.h b/include/drm/drmP.h
index 6105c05..f4ac30f 100644
--- a/include/drm/drmP.h
+++ b/include/drm/drmP.h
@@ -769,6 +769,11 @@ extern int drm_gem_prime_handle_to_fd(struct drm_device *dev,
 		int *prime_fd);
 extern struct drm_gem_object *drm_gem_prime_import(struct drm_device *dev,
 		struct dma_buf *dma_buf);
+
+extern struct drm_gem_object *drm_gem_prime_import_platform(
+		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);
 struct dma_buf *drm_gem_dmabuf_export(struct drm_device *dev,
-- 
2.7.4