freedreno: add fd_pipe refcounting

In mesa/gallium, a pipe_fence can outlive the pipe_context it was
created from.  But to wait on the fence we need to know the submit-
queue (ie. the fd_pipe).

The most straightforward way to fix this is to add reference counting
to the fd_pipe and let the fence hold a reference to the pipe (rather
than hanging on to the context, which might have been destroyed before
the fence).

Signed-off-by: Rob Clark <robclark@freedesktop.org>

freedreno/freedreno-symbol-check

@@ -36,6 +36,7 @@ fd_pipe_del
 fd_pipe_get_param
 fd_pipe_new
 fd_pipe_new2
+fd_pipe_ref
 fd_pipe_wait
 fd_pipe_wait_timeout
 fd_ringbuffer_cmd_count

freedreno/freedreno_drmif.h

@@ -104,6 +104,7 @@ enum fd_version fd_device_version(struct fd_device *dev);
 
 struct fd_pipe * fd_pipe_new(struct fd_device *dev, enum fd_pipe_id id);
 struct fd_pipe * fd_pipe_new2(struct fd_device *dev, enum fd_pipe_id id, uint32_t prio);
+struct fd_pipe * fd_pipe_ref(struct fd_pipe *pipe);
 void fd_pipe_del(struct fd_pipe *pipe);
 int fd_pipe_get_param(struct fd_pipe *pipe, enum fd_param_id param,
 		uint64_t *value);

freedreno/freedreno_pipe.c

@@ -57,6 +57,7 @@ fd_pipe_new2(struct fd_device *dev, enum fd_pipe_id id, uint32_t prio)
 
 	pipe->dev = dev;
 	pipe->id = id;
+	atomic_set(&pipe->refcnt, 1);
 
 	fd_pipe_get_param(pipe, FD_GPU_ID, &val);
 	pipe->gpu_id = val;
@@ -70,8 +71,16 @@ fd_pipe_new(struct fd_device *dev, enum fd_pipe_id id)
 	return fd_pipe_new2(dev, id, 1);
 }
 
+struct fd_pipe * fd_pipe_ref(struct fd_pipe *pipe)
+{
+	atomic_inc(&pipe->refcnt);
+	return pipe;
+}
+
 void fd_pipe_del(struct fd_pipe *pipe)
 {
+	if (!atomic_dec_and_test(&pipe->refcnt))
+		return;
 	pipe->funcs->destroy(pipe);
 }
 

freedreno/freedreno_priv.h

@@ -125,6 +125,7 @@ struct fd_pipe {
 	struct fd_device *dev;
 	enum fd_pipe_id id;
 	uint32_t gpu_id;
+	atomic_t refcnt;
 	const struct fd_pipe_funcs *funcs;
 };