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Date: Thu, 15 Jul 2010 11:31:56 +0800
From: Bryan Wu <bryan.wu@...onical.com>
To: Baruch Siach <baruch@...s.co.il>
CC: netdev@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
Sascha Hauer <kernel@...gutronix.de>,
Greg Ungerer <gerg@...inux.org>,
Wolfram Sang <w.sang@...gutronix.de>
Subject: Re: [PATCH] fec: use interrupt for MDIO completion indication
Baruch,
Thanks for this patch, we tested on our i.MX51 board with Ubuntu. It works fine.
Wolfram, you can pick up this, too. -;)
-Bryan
On 07/12/2010 03:12 PM, Baruch Siach wrote:
> 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@...s.co.il>
> ---
> drivers/net/fec.c | 55 ++++++++++++++++++++++++----------------------------
> 1 files changed, 25 insertions(+), 30 deletions(-)
>
> diff --git a/drivers/net/fec.c b/drivers/net/fec.c
> index edfff92..89f3393 100644
> --- a/drivers/net/fec.c
> +++ b/drivers/net/fec.c
> @@ -187,6 +187,7 @@ 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);
> @@ -205,7 +206,7 @@ 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)
> @@ -334,6 +335,11 @@ 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;
> @@ -608,18 +614,13 @@ 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 |
> @@ -627,13 +628,12 @@ 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 */
> @@ -644,12 +644,10 @@ 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 |
> @@ -658,13 +656,12 @@ 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;
> @@ -1222,7 +1219,8 @@ 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
> @@ -1242,9 +1240,6 @@ 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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