drm: dumb scanout create/mmap for intel/radeon (v3)

This is just an idea that might or might not be a good idea,
it basically adds two ioctls to create a dumb and map a dumb buffer
suitable for scanout. The handle can be passed to the KMS ioctls to create
a framebuffer.

It looks to me like it would be useful in the following cases:
a) in development drivers - we can always provide a shadowfb fallback.
b) libkms users - we can clean up libkms a lot and avoid linking
to libdrm_*.
c) plymouth via libkms is a lot easier.

Userspace bits would be just calls + mmaps. We could probably
mark these handles somehow as not being suitable for acceleartion
so as top stop people who are dumber than dumb.

Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 13 insertions, 0 deletions

diff --git a/drivers/gpu/drm/radeon/radeon_drv.c b/drivers/gpu/drm/radeon/radeon_drv.c
index 275b26a708d6..ca1b7d4c1d83 100644
--- a/drivers/gpu/drm/radeon/radeon_drv.c
+++ b/drivers/gpu/drm/radeon/radeon_drv.c
@@ -84,6 +84,16 @@ extern int radeon_get_crtc_scanoutpos(struct drm_device *dev, int crtc,
 extern struct drm_ioctl_desc radeon_ioctls_kms[];
 extern int radeon_max_kms_ioctl;
 int radeon_mmap(struct file *filp, struct vm_area_struct *vma);
+int radeon_mode_dumb_mmap(struct drm_file *filp,
+                          struct drm_device *dev,
+                          uint32_t handle, uint64_t *offset_p);
+int radeon_mode_dumb_create(struct drm_file *file_priv,
+                            struct drm_device *dev,
+                            struct drm_mode_create_dumb *args);
+int radeon_mode_dumb_destroy(struct drm_file *file_priv,
+                             struct drm_device *dev,
+                             uint32_t handle);
+
 #if defined(CONFIG_DEBUG_FS)
 int radeon_debugfs_init(struct drm_minor *minor);
 void radeon_debugfs_cleanup(struct drm_minor *minor);
@@ -322,6 +332,9 @@ static struct drm_driver kms_driver = {
         .gem_init_object = radeon_gem_object_init,
         .gem_free_object = radeon_gem_object_free,
         .dma_ioctl = radeon_dma_ioctl_kms,
+        .dumb_create = radeon_mode_dumb_create,
+        .dumb_map_offset = radeon_mode_dumb_mmap,
+        .dumb_destroy = radeon_mode_dumb_destroy,
         .fops = {
                  .owner = THIS_MODULE,
                  .open = drm_open,