drm/nouveau/fence: convert to exec engine, and improve channel sync

Now have a somewhat simpler semaphore sync implementation for nv17:nv84,
and a switched to using semaphores as fences on nv84+ and making use of
the hardware's >= acquire operation.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
diff --git a/drivers/gpu/drm/nouveau/nouveau_fence.h b/drivers/gpu/drm/nouveau/nouveau_fence.h
index 1337acb..ec9afa7 100644
--- a/drivers/gpu/drm/nouveau/nouveau_fence.h
+++ b/drivers/gpu/drm/nouveau/nouveau_fence.h
@@ -25,4 +25,27 @@
 void nouveau_fence_idle(struct nouveau_channel *);
 void nouveau_fence_update(struct nouveau_channel *);
 
+struct nouveau_fence_chan {
+	struct list_head pending;
+	spinlock_t lock;
+	u32 sequence;
+};
+
+struct nouveau_fence_priv {
+	struct nouveau_exec_engine engine;
+	int (*emit)(struct nouveau_fence *);
+	int (*sync)(struct nouveau_fence *, struct nouveau_channel *);
+	u32 (*read)(struct nouveau_channel *);
+};
+
+void nouveau_fence_context_new(struct nouveau_fence_chan *);
+void nouveau_fence_context_del(struct nouveau_fence_chan *);
+
+int nv04_fence_create(struct drm_device *dev);
+int nv04_fence_mthd(struct nouveau_channel *, u32, u32, u32);
+
+int nv10_fence_create(struct drm_device *dev);
+int nv84_fence_create(struct drm_device *dev);
+int nvc0_fence_create(struct drm_device *dev);
+
 #endif