drm/nouveau/nvif: access PTIMER through usermode class, if available

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drivers/gpu/drm/nouveau/include/nvif/user.h

@@ -10,6 +10,7 @@ struct nvif_user {
 
 struct nvif_user_func {
 	void (*doorbell)(struct nvif_user *, u32 token);
+	u64 (*time)(struct nvif_user *);
 };
 
 int nvif_user_init(struct nvif_device *);

drivers/gpu/drm/nouveau/nvif/device.c

@@ -27,11 +27,15 @@
 u64
 nvif_device_time(struct nvif_device *device)
 {
+	if (!device->user.func) {
 		struct nv_device_time_v0 args = {};
 		int ret = nvif_object_mthd(&device->object, NV_DEVICE_V0_TIME,
 					   &args, sizeof(args));
 		WARN_ON_ONCE(ret != 0);
 		return args.time;
+	}
+
+	return device->user.func->time(&device->user);
 }
 
 void

drivers/gpu/drm/nouveau/nvif/userc361.c

@@ -21,6 +21,19 @@
  */
 #include <nvif/user.h>
 
+static u64
+nvif_userc361_time(struct nvif_user *user)
+{
+	u32 hi, lo;
+
+	do {
+		hi = nvif_rd32(&user->object, 0x084);
+		lo = nvif_rd32(&user->object, 0x080);
+	} while (hi != nvif_rd32(&user->object, 0x084));
+
+	return ((u64)hi << 32 | lo);
+}
+
 static void
 nvif_userc361_doorbell(struct nvif_user *user, u32 token)
 {
@@ -30,4 +43,5 @@ nvif_userc361_doorbell(struct nvif_user *user, u32 token)
 const struct nvif_user_func
 nvif_userc361 = {
 	.doorbell = nvif_userc361_doorbell,
+	.time = nvif_userc361_time,
 };