From 2d0891e9d8ef7820f61c82ce294b964b7ece7b54 Mon Sep 17 00:00:00 2001
From: Baruch Siach <baruch@tkos.co.il>
Date: Tue, 13 Jul 2010 23:20:33 +0800
Subject: [PATCH] fec: use interrupt for MDIO completion indication
Queued for 2.6.36 in git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next-2.6.git
With the move to phylib (commit e6b043d) I was seeing sporadic "MDIO write
timeout" messages. Measure of the actual time spent showed latency times of
more than 1600us.
This patch uses the MII event indication of the FEC hardware to detect
completion of MDIO transactions.
BugLink: http://bugs.launchpad.net/bugs/546649
BugLink: http://bugs.launchpad.net/bugs/457878
Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Bryan Wu <bryan.wu@canonical.com>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
---
drivers/net/fec.c | 55 +++++++++++++++++++++--------------------------
1 file changed, 25 insertions(+), 30 deletions(-)
diff --git a/drivers/net/fec.c b/drivers/net/fec.c
index 14bcd1b6eef..e0851a803ba 100644
--- a/drivers/net/fec.c
+++ b/drivers/net/fec.c
@@ -198,6 +198,7 @@ struct fec_enet_private {
int index;
int link;
int full_duplex;
+ struct completion mdio_done;
};
static irqreturn_t fec_enet_interrupt(int irq, void * dev_id);
@@ -216,7 +217,7 @@ static void fec_stop(struct net_device *dev);
#define FEC_MMFR_TA (2 << 16)
#define FEC_MMFR_DATA(v) (v & 0xffff)
-#define FEC_MII_TIMEOUT 10000
+#define FEC_MII_TIMEOUT 1000 /* us */
/* Transmitter timeout */
#define TX_TIMEOUT (2 * HZ)
@@ -347,6 +348,11 @@ fec_enet_interrupt(int irq, void * dev_id)
ret = IRQ_HANDLED;
fec_enet_tx(dev);
}
+
+ if (int_events & FEC_ENET_MII) {
+ ret = IRQ_HANDLED;
+ complete(&fep->mdio_done);
+ }
} while (int_events);
return ret;
@@ -621,18 +627,13 @@ spin_unlock:
phy_print_status(phy_dev);
}
-/*
- * NOTE: a MII transaction is during around 25 us, so polling it...
- */
static int fec_enet_mdio_read(struct mii_bus *bus, int mii_id, int regnum)
{
struct fec_enet_private *fep = bus->priv;
- int timeout = FEC_MII_TIMEOUT;
+ unsigned long time_left;
fep->mii_timeout = 0;
-
- /* clear MII end of transfer bit*/
- writel(FEC_ENET_MII, fep->hwp + FEC_IEVENT);
+ init_completion(&fep->mdio_done);
/* start a read op */
writel(FEC_MMFR_ST | FEC_MMFR_OP_READ |
@@ -640,13 +641,12 @@ static int fec_enet_mdio_read(struct mii_bus *bus, int mii_id, int regnum)
FEC_MMFR_TA, fep->hwp + FEC_MII_DATA);
/* wait for end of transfer */
- while (!(readl(fep->hwp + FEC_IEVENT) & FEC_ENET_MII)) {
- cpu_relax();
- if (timeout-- < 0) {
- fep->mii_timeout = 1;
- printk(KERN_ERR "FEC: MDIO read timeout\n");
- return -ETIMEDOUT;
- }
+ time_left = wait_for_completion_timeout(&fep->mdio_done,
+ usecs_to_jiffies(FEC_MII_TIMEOUT));
+ if (time_left == 0) {
+ fep->mii_timeout = 1;
+ printk(KERN_ERR "FEC: MDIO read timeout\n");
+ return -ETIMEDOUT;
}
/* return value */
@@ -657,12 +657,10 @@ static int fec_enet_mdio_write(struct mii_bus *bus, int mii_id, int regnum,
u16 value)
{
struct fec_enet_private *fep = bus->priv;
- int timeout = FEC_MII_TIMEOUT;
+ unsigned long time_left;
fep->mii_timeout = 0;
-
- /* clear MII end of transfer bit*/
- writel(FEC_ENET_MII, fep->hwp + FEC_IEVENT);
+ init_completion(&fep->mdio_done);
/* start a read op */
writel(FEC_MMFR_ST | FEC_MMFR_OP_READ |
@@ -671,13 +669,12 @@ static int fec_enet_mdio_write(struct mii_bus *bus, int mii_id, int regnum,
fep->hwp + FEC_MII_DATA);
/* wait for end of transfer */
- while (!(readl(fep->hwp + FEC_IEVENT) & FEC_ENET_MII)) {
- cpu_relax();
- if (timeout-- < 0) {
- fep->mii_timeout = 1;
- printk(KERN_ERR "FEC: MDIO write timeout\n");
- return -ETIMEDOUT;
- }
+ time_left = wait_for_completion_timeout(&fep->mdio_done,
+ usecs_to_jiffies(FEC_MII_TIMEOUT));
+ if (time_left == 0) {
+ fep->mii_timeout = 1;
+ printk(KERN_ERR "FEC: MDIO write timeout\n");
+ return -ETIMEDOUT;
}
return 0;
@@ -1244,7 +1241,8 @@ fec_restart(struct net_device *dev, int duplex)
writel(0, fep->hwp + FEC_R_DES_ACTIVE);
/* Enable interrupts we wish to service */
- writel(FEC_ENET_TXF | FEC_ENET_RXF, fep->hwp + FEC_IMASK);
+ writel(FEC_ENET_TXF | FEC_ENET_RXF | FEC_ENET_MII,
+ fep->hwp + FEC_IMASK);
}
static void
@@ -1264,9 +1262,6 @@ fec_stop(struct net_device *dev)
writel(1, fep->hwp + FEC_ECNTRL);
udelay(10);
- /* Clear outstanding MII command interrupts. */
- writel(FEC_ENET_MII, fep->hwp + FEC_IEVENT);
-
writel(fep->phy_speed, fep->hwp + FEC_MII_SPEED);
}
--
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