diff for udmabuf.py (https://github.com/ikwzm/FPGA-SoC-Linux-Example-1-ZYBO-Z7)

gistfile1.txt

+    def config_sync(self, size, direc):
+        with open(self.class_path + '/sync_size', mode='w') as f:
+            f.write(str(size))
+        with open(self.class_path + '/sync_direction', mode='w') as f:
+            f.write(str(direc))
+
+    def sync_for_cpu(self):
+        with open(self.class_path + '/sync_for_cpu', mode='w') as f:
+            f.write(str(1))
+
+    def sync_for_device(self):
+        with open(self.class_path + '/sync_for_device', mode='w') as f:
+            f.write(str(1))