netdev - [PATCH] iMX: Fix for missed MII interrupts and MDIO timeouts when FEC is in STOP

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Date:	Fri, 22 Apr 2011 00:17:12 +0200
From:	Matteo Fortini <matteo.fortini@...il.com>
To:	netdev@...r.kernel.org
Subject: [PATCH] iMX: Fix for missed MII interrupts and MDIO timeouts when FEC
 is in STOP

We are experiencing unrecoverable timeouts if we disconnect a cable from the
FEC. This patch solves the issue by keeping the Ethernet enabled even in
STOP. The RM doesn't state it, but i seems that if disabled, the Ethernet is
not issuing interrupts to the core.
(See
http://forums.freescale.com/t5/i-MX-Microprocessors/iMX28-Network-MDIO-timeout-recovery-and-lost-IRQs/td-p/73309
)

The patch is against Freescale iMX tree from opensource.freescale.com/git

---
 drivers/net/fec.c |    7 ++++++-
 1 files changed, 6 insertions(+), 1 deletions(-)

diff --git a/drivers/net/fec.c b/drivers/net/fec.c
index d0e2e69..26ea72d 100644
--- a/drivers/net/fec.c
+++ b/drivers/net/fec.c
@@ -121,8 +121,10 @@
 #if defined(CONFIG_FEC_1588) && defined(CONFIG_ARCH_MX28)
 #define FEC_DEFAULT_IMASK (FEC_ENET_TXF | FEC_ENET_RXF | FEC_ENET_MII | \
                FEC_ENET_TS_AVAIL | FEC_ENET_TS_TIMER)
+#define FEC_STOP_IMASK (FEC_ENET_MII)
 #else
 #define FEC_DEFAULT_IMASK (FEC_ENET_TXF | FEC_ENET_RXF | FEC_ENET_MII)
+#define FEC_STOP_IMASK (FEC_ENET_MII)
 #endif

 /* The FEC stores dest/src/type, data, and checksum for receive packets.
@@ -1409,6 +1411,9 @@ fec_stop(struct net_device *dev)
    writel(1, fep->hwp + FEC_ECNTRL);
    udelay(10);

+    /* Reactivate the controller to get the IRQs */
+    writel(0x00000002, fep->hwp + FEC_ECNTRL);
+
 #ifdef CONFIG_ARCH_MXS
    /* Check MII or RMII */
    if (fep->phy_interface == PHY_INTERFACE_MODE_RMII)
@@ -1423,7 +1428,7 @@ fec_stop(struct net_device *dev)
    writel(fep->phy_speed, fep->hwp + FEC_MII_SPEED);
    if (fep->ptimer_present)
        fec_ptp_stop(fep->ptp_priv);
-    writel(FEC_DEFAULT_IMASK, fep->hwp + FEC_IMASK);
+    writel(FEC_STOP_IMASK, fep->hwp + FEC_IMASK);

    netif_stop_queue(dev);
    fep->link = 0;
--
1.7.4.2
--
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