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[LS1046A] RGMII TX clock has incorrect frequency (5MHz)

Question asked by Łukasz Łaguna on Aug 9, 2019
Latest reply on Aug 19, 2019 by Łukasz Łaguna

Hello. We are bringing up the custom board based on the NXP LS1046A and we have a problem to get successful ping using RGMII interfaces (TI DP83867 PHY):


=> ping
Using FM1@DTSEC3 device


ARP Retry count exceeded; starting again
ping failed; host is not alive


PHYs are connected as 100Mb (SGMII connected as 1Gb with the same PHYs works fine).


We are debugging it on really low level using oscilloscope. Comparing the signals to the signals from the reference platform LS1046ARDB, we currently have the correct signals on RX_Data and RX_Clock lines (proper CLK frequency 25MHz, proper skew between data signals and clk signal), but the ping still fails, so we started examination of the TX lines and it turned out that TXC signal frequency is equal to 5MHz and we think this is the last problem, which blocks us from getting successful ping.


From what we were able to observe, SPEED_100 is selected in fm/memac.c driver.


Maybe you have an idea what can be wrong (PLLs configuration, MAC configuration?) and what can we do to fix this problem?