fec: use interrupt for MDIO completion indication
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.
Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/fec.c b/drivers/net/fec.c
index b4afd7a..937f1b4 100644
--- a/drivers/net/fec.c
+++ b/drivers/net/fec.c
@@ -187,6 +187,7 @@
int index;
int link;
int full_duplex;
+ struct completion mdio_done;
};
static irqreturn_t fec_enet_interrupt(int irq, void * dev_id);
@@ -205,7 +206,7 @@
#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)
@@ -334,6 +335,11 @@
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;
@@ -608,18 +614,13 @@
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 |
@@ -627,13 +628,12 @@
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 */
@@ -644,12 +644,10 @@
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 |
@@ -658,13 +656,12 @@
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;
@@ -1216,7 +1213,8 @@
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
@@ -1236,9 +1234,6 @@
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);
}