[RFC PATCHv2 1/3] drm/vgem: Add a dummy platform device

[Laura Abbott <labbott@redhat.com>]

The vgem driver is currently registered independent of any actual
device. Some usage of the dmabuf APIs require an actual device structure
to do anything. Register a dummy platform device for use with dmabuf.

Signed-off-by: Laura Abbott <labbott@redhat.com>
---
v2: Store the platform device in the platformdev field instead of the
regular device structure.
---
 drivers/gpu/drm/vgem/vgem_drv.c | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/vgem/vgem_drv.c b/drivers/gpu/drm/vgem/vgem_drv.c
index a1f42d1..1b02e56 100644
--- a/drivers/gpu/drm/vgem/vgem_drv.c
+++ b/drivers/gpu/drm/vgem/vgem_drv.c
@@ -335,11 +335,20 @@ static int __init vgem_init(void)
 	int ret;
 
 	vgem_device = drm_dev_alloc(&vgem_driver, NULL);
-	if (IS_ERR(vgem_device)) {
-		ret = PTR_ERR(vgem_device);
+	if (IS_ERR(vgem_device))
+		return PTR_ERR(vgem_device);
+
+	vgem_device->platformdev = platform_device_register_simple("vgem",
+					-1, NULL, 0);
+
+	if (!vgem_device->platformdev) {
+		ret = -ENODEV;
 		goto out;
 	}
 
+	dma_coerce_mask_and_coherent(&vgem_device->platformdev->dev,
+					DMA_BIT_MASK(64));
+
 	ret  = drm_dev_register(vgem_device, 0);
 	if (ret)
 		goto out_unref;
@@ -347,13 +356,15 @@ static int __init vgem_init(void)
 	return 0;
 
 out_unref:
-	drm_dev_unref(vgem_device);
+	platform_device_unregister(vgem_device->platformdev);
 out:
+	drm_dev_unref(vgem_device);
 	return ret;
 }
 
 static void __exit vgem_exit(void)
 {
+	platform_device_unregister(vgem_device->platformdev);
 	drm_dev_unregister(vgem_device);
 	drm_dev_unref(vgem_device);
 }
-- 
2.7.4