net: fsl: fec: handle 10Mbps speed in RMII mode

when the link is 10 Mbps and the mode is RMII, it's necessary
to set FRCONT to 1 in MIIGSK_CFGR to divide the RMII source
clock by 10 in order to support 10 Mbps operations.

Signed-off-by: Eric Bénard <eric@eukrea.com>
Acked-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 10 insertions, 3 deletions

diff --git a/drivers/net/ethernet/freescale/fec.c b/drivers/net/ethernet/freescale/fec.c
index 236cc892ec3e..7b25e9cf13f6 100644
--- a/drivers/net/ethernet/freescale/fec.c
+++ b/drivers/net/ethernet/freescale/fec.c
@@ -476,6 +476,7 @@ fec_restart(struct net_device *ndev, int duplex)
         } else {
 #ifdef FEC_MIIGSK_ENR
                 if (id_entry->driver_data & FEC_QUIRK_USE_GASKET) {
+                        u32 cfgr;
                         /* disable the gasket and wait */
                         writel(0, fep->hwp + FEC_MIIGSK_ENR);
                         while (readl(fep->hwp + FEC_MIIGSK_ENR) & 4)
@@ -486,9 +487,11 @@ fec_restart(struct net_device *ndev, int duplex)
                          *   RMII, 50 MHz, no loopback, no echo
                          *   MII, 25 MHz, no loopback, no echo
                          */
-                        writel((fep->phy_interface == PHY_INTERFACE_MODE_RMII) ?
-                                        1 : 0, fep->hwp + FEC_MIIGSK_CFGR);
-
+                        cfgr = (fep->phy_interface == PHY_INTERFACE_MODE_RMII)
+                                ? BM_MIIGSK_CFGR_RMII : BM_MIIGSK_CFGR_MII;
+                        if (fep->phy_dev && fep->phy_dev->speed == SPEED_10)
+                                cfgr |= BM_MIIGSK_CFGR_FRCONT_10M;
+                        writel(cfgr, fep->hwp + FEC_MIIGSK_CFGR);
 
                         /* re-enable the gasket */
                         writel(2, fep->hwp + FEC_MIIGSK_ENR);
diff --git a/drivers/net/ethernet/freescale/fec.h b/drivers/net/ethernet/freescale/fec.h
index 8b2c6d797e6d..8408c627b195 100644
--- a/drivers/net/ethernet/freescale/fec.h
+++ b/drivers/net/ethernet/freescale/fec.h
@@ -47,6 +47,10 @@
 #define FEC_MIIGSK_CFGR         0x300 /* MIIGSK Configuration reg */
 #define FEC_MIIGSK_ENR          0x308 /* MIIGSK Enable reg */
 
+#define BM_MIIGSK_CFGR_MII              0x00
+#define BM_MIIGSK_CFGR_RMII             0x01
+#define BM_MIIGSK_CFGR_FRCONT_10M       0x40
+
 #else
 
 #define FEC_ECNTRL              0x000 /* Ethernet control reg */