net: fec: Fix FEC_ECR_EN1588 being cleared on link-down

FEC_ECR_EN1588 bit gets cleared after MAC reset in `fec_stop()`, which
makes all 1588 functionality shut down, and all the extended registers
disappear, on link-down, making the adapter fall back to compatibility
"dumb mode". However, some functionality needs to be retained (e.g. PPS)
even without link.

Fixes: 6605b730c061 ("FEC: Add time stamping code and a PTP hardware clock")
Cc: Richard Cochran <richardcochran@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://lore.kernel.org/netdev/5fa9fadc-a89d-467a-aae9-c65469ff5fe1@lunn.ch/
Signed-off-by: Csókás, Bence <csokas.bence@prolan.hu>
Reviewed-by: Wei Fang <wei.fang@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/freescale/fec_main.c b/drivers/net/ethernet/freescale/fec_main.c
index 881ece735dcf1470fed863fdbb765e231ca2dbbf..fb19295529a218343d857656fb50d4516d5f8a1a 100644 (file)
--- a/drivers/net/ethernet/freescale/fec_main.c
+++ b/drivers/net/ethernet/freescale/fec_main.c
@@ -1361,6 +1361,12 @@ fec_stop(struct net_device *ndev)
                writel(FEC_ECR_ETHEREN, fep->hwp + FEC_ECNTRL);
                writel(rmii_mode, fep->hwp + FEC_R_CNTRL);
        }
+
+       if (fep->bufdesc_ex) {
+               val = readl(fep->hwp + FEC_ECNTRL);
+               val |= FEC_ECR_EN1588;
+               writel(val, fep->hwp + FEC_ECNTRL);
+       }
 }
 
 static void