mm-drivers: hw_fence: move mem barrier before mem read

Move memory barriers to ensure data is available before
the read of indexes from the queues.

Change-Id: I3b5a7903f038cc62b461fbfc9cbeb143b862a1f1
Signed-off-by: Ingrid Gallardo <[email protected]>

hw_fence/src/hw_fence_drv_priv.c

@@ -166,13 +166,13 @@ int hw_fence_read_queue(struct msm_hw_fence_client *hw_fence_client,
 		return -EINVAL;
 	}
 
+	/* Make sure data is ready before read */
+	mb();
+
 	/* Get read and write index */
 	read_idx = readl_relaxed(&hfi_header->read_index);
 	write_idx = readl_relaxed(&hfi_header->write_index);
 
-	/* Make sure we read the values */
-	rmb();
-
 	HWFNC_DBG_Q("read client:%d rd_ptr:0x%pK wr_ptr:0x%pK rd_idx:%d wr_idx:%d queue:0x%pK\n",
 		hw_fence_client->client_id, &hfi_header->read_index, &hfi_header->write_index,
 		read_idx, write_idx, queue);
@@ -274,13 +274,13 @@ int hw_fence_update_queue(struct hw_fence_driver_data *drv_data,
 		GLOBAL_ATOMIC_STORE(&drv_data->client_lock_tbl[lock_idx], 1); /* lock */
 	}
 
+	/* Make sure data is ready before read */
+	mb();
+
 	/* Get read and write index */
 	read_idx = readl_relaxed(&hfi_header->read_index);
 	write_idx = readl_relaxed(&hfi_header->write_index);
 
-	/* Make sure we read the values */
-	rmb();
-
 	HWFNC_DBG_Q("wr client:%d rd_ptr:0x%pK wr_ptr:0x%pK rd_idx:%d wr_idx:%d q:0x%pK type:%d\n",
 		hw_fence_client->client_id, &hfi_header->read_index, &hfi_header->write_index,
 		read_idx, write_idx, queue, queue_type);