drm: introduce sync objects (v4)

Sync objects are new toplevel drm object, that contain a
pointer to a fence. This fence can be updated via command
submission ioctls via drivers.

There is also a generic wait obj API modelled on the vulkan
wait API (with code modelled on some amdgpu code).

These objects can be converted to an opaque fd that can be
passes between processes.

v2: rename reference/unreference to put/get (Chris)
fix leaked reference (David Zhou)
drop mutex in favour of cmpxchg (Chris)
v3: cleanups from danvet, rebase on drm_fops rename
check fd_flags is 0 in ioctls.
v4: export find/free, change replace fence to take a
syncobj. In order to support lookup first, replace
later semantics which seem in the end to be cleaner.

Reviewed-by: Sean Paul <seanpaul@chromium.org>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 24 insertions, 0 deletions

diff --git a/include/uapi/drm/drm.h b/include/uapi/drm/drm.h
index 42d9f64ce416..96c5c789e73d 100644
--- a/include/uapi/drm/drm.h
+++ b/include/uapi/drm/drm.h
@@ -648,6 +648,7 @@ struct drm_gem_open {
 #define DRM_CAP_ADDFB2_MODIFIERS        0x10
 #define DRM_CAP_PAGE_FLIP_TARGET        0x11
 #define DRM_CAP_CRTC_IN_VBLANK_EVENT    0x12
+#define DRM_CAP_SYNCOBJ         0x13
 
 /** DRM_IOCTL_GET_CAP ioctl argument type */
 struct drm_get_cap {
@@ -697,6 +698,24 @@ struct drm_prime_handle {
         __s32 fd;
 };
 
+struct drm_syncobj_create {
+        __u32 handle;
+        __u32 flags;
+};
+
+struct drm_syncobj_destroy {
+        __u32 handle;
+        __u32 pad;
+};
+
+struct drm_syncobj_handle {
+        __u32 handle;
+        __u32 flags;
+
+        __s32 fd;
+        __u32 pad;
+};
+
 #if defined(__cplusplus)
 }
 #endif
@@ -815,6 +834,11 @@ extern "C" {
 #define DRM_IOCTL_MODE_CREATEPROPBLOB   DRM_IOWR(0xBD, struct drm_mode_create_blob)
 #define DRM_IOCTL_MODE_DESTROYPROPBLOB  DRM_IOWR(0xBE, struct drm_mode_destroy_blob)
 
+#define DRM_IOCTL_SYNCOBJ_CREATE        DRM_IOWR(0xBF, struct drm_syncobj_create)
+#define DRM_IOCTL_SYNCOBJ_DESTROY       DRM_IOWR(0xC0, struct drm_syncobj_destroy)
+#define DRM_IOCTL_SYNCOBJ_HANDLE_TO_FD  DRM_IOWR(0xC1, struct drm_syncobj_handle)
+#define DRM_IOCTL_SYNCOBJ_FD_TO_HANDLE  DRM_IOWR(0xC2, struct drm_syncobj_handle)
+
 /**
  * Device specific ioctls should only be in their respective headers
  * The device specific ioctl range is from 0x40 to 0x9f.