gpu: host1x: Implement job tracking using DMA fences

In anticipation of removal of the intr API, implement job tracking
using DMA fences instead. The main two things about this are
making cdma_update schedule the work since fence completion can
now be called from interrupt context, and some complication in
ensuring the callback is not running when we free the fence.

Signed-off-by: Mikko Perttunen <mperttunen@nvidia.com>
Change-Id: I25f7f5a6cad24a00563eed79e0e17b1df1eadcdc
Reviewed-on: https://git-master.nvidia.com/r/c/linux-nvidia/+/2786636
Reviewed-by: Jonathan Hunter <jonathanh@nvidia.com>
GVS: Gerrit_Virtual_Submit <buildbot_gerritrpt@nvidia.com>

drivers/gpu/host1x/include/linux/host1x-next.h

@@ -8,6 +8,7 @@
 
 #include <linux/device.h>
 #include <linux/dma-direction.h>
+#include <linux/dma-fence.h>
 #include <linux/spinlock.h>
 #include <linux/types.h>
 
@@ -296,8 +297,10 @@ struct host1x_job {
 	/* Non-job tracking related syncpoint */
 	struct host1x_syncpt *secondary_syncpt;
 
-	/* Completion waiter ref */
-	void *waiter;
+	/* Completion fence for job tracking */
+	struct dma_fence *fence;
+	struct dma_fence_cb fence_cb;
+	struct completion fence_cb_done;
 
 	/* Maximum time to wait for this job */
 	unsigned int timeout;