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Message-ID: <20090910214812.GA30564@oksana.dev.rtsoft.ru>
Date: Fri, 11 Sep 2009 01:48:12 +0400
From: Anton Vorontsov <avorontsov@...mvista.com>
To: Scott Wood <scottwood@...escale.com>
Cc: David Miller <davem@...emloft.net>, netdev@...r.kernel.org,
Andy Fleming <afleming@...escale.com>,
Timur Tabi <timur@...escale.com>, linuxppc-dev@...abs.org
Subject: [PATCH v3 3/3] ucc_geth: Fix hangs after switching from full to
half duplex
MPC8360 QE UCC ethernet controllers hang when changing link duplex
under a load (a bit of NFS activity is enough).
PHY: mdio@...02120:00 - Link is Up - 1000/Full
sh-3.00# ethtool -s eth0 speed 100 duplex half autoneg off
PHY: mdio@...02120:00 - Link is Down
PHY: mdio@...02120:00 - Link is Up - 100/Half
NETDEV WATCHDOG: eth0 (ucc_geth): transmit queue 0 timed out
------------[ cut here ]------------
Badness at c01fcbd0 [verbose debug info unavailable]
NIP: c01fcbd0 LR: c01fcbd0 CTR: c0194e44
...
The cure is to disable the controller before changing speed/duplex
and enable it afterwards.
Though, disabling the controller might take quite a while, so we
better not grab any spinlocks in adjust_link(). Instead, we quiesce
the driver's activity, and only then disable the controller.
Signed-off-by: Anton Vorontsov <avorontsov@...mvista.com>
---
On Fri, Sep 11, 2009 at 01:09:36AM +0400, Anton Vorontsov wrote:
> On Thu, Sep 10, 2009 at 11:40:53PM +0400, Anton Vorontsov wrote:
> > On Thu, Sep 10, 2009 at 01:04:32PM -0500, Scott Wood wrote:
> > > Anton Vorontsov wrote:
> > > >MPC8360 QE UCC ethernet controllers hang when changing link duplex
> > > >under a load (a bit of NFS activity is enough).
> > > >
> > > > PHY: mdio@...02120:00 - Link is Up - 1000/Full
> > > > sh-3.00# ethtool -s eth0 speed 100 duplex half autoneg off
> > > > PHY: mdio@...02120:00 - Link is Down
> > > > PHY: mdio@...02120:00 - Link is Up - 100/Half
> > > > NETDEV WATCHDOG: eth0 (ucc_geth): transmit queue 0 timed out
> > > > ------------[ cut here ]------------
> > > > Badness at c01fcbd0 [verbose debug info unavailable]
> > > > NIP: c01fcbd0 LR: c01fcbd0 CTR: c0194e44
> > > > ...
> > > >
> > > >The cure is to disable the controller before changing speed/duplex
> > > >and enable it afterwards.
> > > >
> > > >Since ugeth_graceful_stop_{tx,rx} now may be called from an atomic
> > > >context, switch the two functions from msleep() to mdelay().
> > >
> > > Ouch.
> >
> > Yeah, right... delaying for 10ms with irqs off isn't good.
> >
> > > Can we put this in a workqueue or something?
> >
> > adjust_link() itself isn't called from an atomic context.
>
> Oops. I though that phylib calls us from a workqueue, not a timer. Hm...
>
> Will be a little bit more work..
Ignore me. I'm working on two kernel versions in parallel (2.6.21 and
mainline), and it's 2.6.21 where phylib uses a timer. Mainline is OK.
How about this patch?
drivers/net/ucc_geth.c | 36 +++++++++++++++++++++++++++++++-----
1 files changed, 31 insertions(+), 5 deletions(-)
diff --git a/drivers/net/ucc_geth.c b/drivers/net/ucc_geth.c
index 2a2c973..232fef9 100644
--- a/drivers/net/ucc_geth.c
+++ b/drivers/net/ucc_geth.c
@@ -1560,6 +1560,25 @@ static int ugeth_disable(struct ucc_geth_private *ugeth, enum comm_dir mode)
return 0;
}
+static void ugeth_quiesce(struct ucc_geth_private *ugeth)
+{
+ /* Wait for and prevent any further xmits. */
+ netif_tx_disable(ugeth->ndev);
+
+ /* Disable the interrupt to avoid NAPI rescheduling. */
+ disable_irq(ugeth->ug_info->uf_info.irq);
+
+ /* Stop NAPI, and possibly wait for its completion. */
+ napi_disable(&ugeth->napi);
+}
+
+static void ugeth_activate(struct ucc_geth_private *ugeth)
+{
+ napi_enable(&ugeth->napi);
+ enable_irq(ugeth->ug_info->uf_info.irq);
+ netif_tx_wake_all_queues(ugeth->ndev);
+}
+
/* Called every time the controller might need to be made
* aware of new link state. The PHY code conveys this
* information through variables in the ugeth structure, and this
@@ -1573,14 +1592,11 @@ static void adjust_link(struct net_device *dev)
struct ucc_geth __iomem *ug_regs;
struct ucc_fast __iomem *uf_regs;
struct phy_device *phydev = ugeth->phydev;
- unsigned long flags;
int new_state = 0;
ug_regs = ugeth->ug_regs;
uf_regs = ugeth->uccf->uf_regs;
- spin_lock_irqsave(&ugeth->lock, flags);
-
if (phydev->link) {
u32 tempval = in_be32(&ug_regs->maccfg2);
u32 upsmr = in_be32(&uf_regs->upsmr);
@@ -1631,9 +1647,21 @@ static void adjust_link(struct net_device *dev)
ugeth->oldspeed = phydev->speed;
}
+ /*
+ * To change the MAC configuration we need to disable the
+ * controller. To do so, we have to either grab ugeth->lock,
+ * which is a bad idea since 'graceful stop' commands might
+ * take quite a while, or we can quiesce driver's activity.
+ */
+ ugeth_quiesce(ugeth);
+ ugeth_disable(ugeth, COMM_DIR_RX_AND_TX);
+
out_be32(&ug_regs->maccfg2, tempval);
out_be32(&uf_regs->upsmr, upsmr);
+ ugeth_enable(ugeth, COMM_DIR_RX_AND_TX);
+ ugeth_activate(ugeth);
+
if (!ugeth->oldlink) {
new_state = 1;
ugeth->oldlink = 1;
@@ -1647,8 +1675,6 @@ static void adjust_link(struct net_device *dev)
if (new_state && netif_msg_link(ugeth))
phy_print_status(phydev);
-
- spin_unlock_irqrestore(&ugeth->lock, flags);
}
/* Initialize TBI PHY interface for communicating with the
--
1.6.3.3
--
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