def METHOD_NAME(self, fragment):
    Xilinx7SeriesPlatform.METHOD_NAME(self, fragment)
    self.add_period_constraint(self.lookup_request("clk200",        loose=True), 1e9/200e6)
    self.add_period_constraint(self.lookup_request("eth_clocks:rx", loose=True), 1e9/125e6)