From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bryan Wu Subject: [PATCH 1/2] netdev/fec: fix performance impact from mdio poll operation Date: Fri, 7 May 2010 10:27:18 +0800 Message-ID: <1273199239-11057-2-git-send-email-bryan.wu@canonical.com> References: <1273199239-11057-1-git-send-email-bryan.wu@canonical.com> To: davem@davemloft.net, Sascha Hauer , Greg Ungerer , Amit Kucheria , netdev@vger.kernel.org, linux-kernel@vger.kernel.org Return-path: Received: from adelie.canonical.com ([91.189.90.139]:51864 "EHLO adelie.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752688Ab0EGCaT (ORCPT ); Thu, 6 May 2010 22:30:19 -0400 In-Reply-To: <1273199239-11057-1-git-send-email-bryan.wu@canonical.com> Sender: netdev-owner@vger.kernel.org List-ID: BugLink: http://bugs.launchpad.net/bugs/546649 BugLink: http://bugs.launchpad.net/bugs/457878 After introducing phylib supporting, users experienced performace drop. That is because of the mdio polling operation of phylib. Use msleep to replace the busy waiting cpu_relax() and remove the warning message. Signed-off-by: Bryan Wu Acked-by: Andy Whitcroft --- drivers/net/fec.c | 45 +++++++++++++++++++++------------------------ 1 files changed, 21 insertions(+), 24 deletions(-) diff --git a/drivers/net/fec.c b/drivers/net/fec.c index 2b1651a..9c58f6b 100644 --- a/drivers/net/fec.c +++ b/drivers/net/fec.c @@ -203,7 +203,7 @@ 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 10 /* Transmitter timeout */ #define TX_TIMEOUT (2 * HZ) @@ -611,13 +611,29 @@ spin_unlock: /* * 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) +static int fec_enet_mdio_poll(struct fec_enet_private *fep) { - struct fec_enet_private *fep = bus->priv; int timeout = FEC_MII_TIMEOUT; fep->mii_timeout = 0; + /* wait for end of transfer */ + while (!(readl(fep->hwp + FEC_IEVENT) & FEC_ENET_MII)) { + msleep(1); + if (timeout-- < 0) { + fep->mii_timeout = 1; + break; + } + } + + return 0; +} + +static int fec_enet_mdio_read(struct mii_bus *bus, int mii_id, int regnum) +{ + struct fec_enet_private *fep = bus->priv; + + /* clear MII end of transfer bit*/ writel(FEC_ENET_MII, fep->hwp + FEC_IEVENT); @@ -626,15 +642,7 @@ static int fec_enet_mdio_read(struct mii_bus *bus, int mii_id, int regnum) FEC_MMFR_PA(mii_id) | FEC_MMFR_RA(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; - } - } + fec_enet_mdio_poll(fep); /* return value */ return FEC_MMFR_DATA(readl(fep->hwp + FEC_MII_DATA)); @@ -644,9 +652,6 @@ 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; - - fep->mii_timeout = 0; /* clear MII end of transfer bit*/ writel(FEC_ENET_MII, fep->hwp + FEC_IEVENT); @@ -657,15 +662,7 @@ static int fec_enet_mdio_write(struct mii_bus *bus, int mii_id, int regnum, FEC_MMFR_TA | FEC_MMFR_DATA(value), 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; - } - } + fec_enet_mdio_poll(fep); return 0; } -- 1.7.0.1