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Message-Id: <1232460114-13469-1-git-send-email-steve.glendinning@smsc.com>
Date: Tue, 20 Jan 2009 14:01:54 +0000
From: Steve Glendinning <steve.glendinning@...c.com>
To: netdev@...r.kernel.org
Cc: David Miller <davem@...emloft.net>,
Ian Saturley <ian.saturley@...c.com>,
Steve Glendinning <steve.glendinning@...c.com>
Subject: [RFC PATCH] smsc911x: protect INT_EN read-modify-write with spinlock
This patch adds a new spinlock to protect read-modify-writes to the
INT_EN register when enabling and disabling interrupt sources.
I haven't actually seen any devices lock up, but I think there's a
possibility and I'd like to eliminate it.
Should I add this new spinlock, or should I extend the mac_lock
to also cover these sections (renaming it to simply "lock")?
Signed-off-by: Steve Glendinning <steve.glendinning@...c.com>
---
drivers/net/smsc911x.c | 22 ++++++++++++++++++++++
1 files changed, 22 insertions(+), 0 deletions(-)
diff --git a/drivers/net/smsc911x.c b/drivers/net/smsc911x.c
index f513bdf..3f52d23 100644
--- a/drivers/net/smsc911x.c
+++ b/drivers/net/smsc911x.c
@@ -88,6 +88,9 @@ struct smsc911x_data {
* unused with a 32-bit bus */
spinlock_t dev_lock;
+ /* spinlock to protect INT_EN read-modify-writes */
+ spinlock_t int_lock;
+
struct phy_device *phy_dev;
struct mii_bus *mii_bus;
int phy_irq[PHY_MAX_ADDR];
@@ -981,13 +984,16 @@ static int smsc911x_poll(struct napi_struct *napi, int budget)
if (!rxstat) {
unsigned int temp;
+ unsigned long flags;
/* We processed all packets available. Tell NAPI it can
* stop polling then re-enable rx interrupts */
smsc911x_reg_write(pdata, INT_STS, INT_STS_RSFL_);
netif_rx_complete(napi);
+ spin_lock_irqsave(&pdata->int_lock, flags);
temp = smsc911x_reg_read(pdata, INT_EN);
temp |= INT_EN_RSFL_EN_;
smsc911x_reg_write(pdata, INT_EN, temp);
+ spin_unlock_irqrestore(&pdata->int_lock, flags);
break;
}
@@ -1178,7 +1184,9 @@ static int smsc911x_open(struct net_device *dev)
spin_unlock_irq(&pdata->mac_lock);
/* Initialise irqs, but leave all sources disabled */
+ spin_lock_irq(&pdata->int_lock);
smsc911x_reg_write(pdata, INT_EN, 0);
+ spin_unlock_irq(&pdata->int_lock);
smsc911x_reg_write(pdata, INT_STS, 0xFFFFFFFF);
/* Set interrupt deassertion to 100uS */
@@ -1204,9 +1212,11 @@ static int smsc911x_open(struct net_device *dev)
pdata->software_irq_signal = 0;
smp_wmb();
+ spin_lock_irq(&pdata->int_lock);
temp = smsc911x_reg_read(pdata, INT_EN);
temp |= INT_EN_SW_INT_EN_;
smsc911x_reg_write(pdata, INT_EN, temp);
+ spin_unlock_irq(&pdata->int_lock);
timeout = 1000;
while (timeout--) {
@@ -1245,9 +1255,11 @@ static int smsc911x_open(struct net_device *dev)
/* enable NAPI polling before enabling RX interrupts */
napi_enable(&pdata->napi);
+ spin_lock_irq(&pdata->int_lock);
temp = smsc911x_reg_read(pdata, INT_EN);
temp |= (INT_EN_TDFA_EN_ | INT_EN_RSFL_EN_);
smsc911x_reg_write(pdata, INT_EN, temp);
+ spin_unlock_irq(&pdata->int_lock);
spin_lock_irq(&pdata->mac_lock);
temp = smsc911x_mac_read(pdata, MAC_CR);
@@ -1419,9 +1431,11 @@ static void smsc911x_set_multicast_list(struct net_device *dev)
/* Request the hardware to stop, then perform the
* update when we get an RX_STOP interrupt */
smsc911x_reg_write(pdata, INT_STS, INT_STS_RXSTOP_INT_);
+ spin_lock(&pdata->int_lock);
temp = smsc911x_reg_read(pdata, INT_EN);
temp |= INT_EN_RXSTOP_INT_EN_;
smsc911x_reg_write(pdata, INT_EN, temp);
+ spin_unlock(&pdata->int_lock);
temp = smsc911x_mac_read(pdata, MAC_CR);
temp &= ~(MAC_CR_RXEN_);
@@ -1445,12 +1459,15 @@ static irqreturn_t smsc911x_irqhandler(int irq, void *dev_id)
u32 intsts = smsc911x_reg_read(pdata, INT_STS);
u32 inten = smsc911x_reg_read(pdata, INT_EN);
int serviced = IRQ_NONE;
+ unsigned long flags;
u32 temp;
if (unlikely(intsts & inten & INT_STS_SW_INT_)) {
+ spin_lock_irqsave(&pdata->int_lock, flags);
temp = smsc911x_reg_read(pdata, INT_EN);
temp &= (~INT_EN_SW_INT_EN_);
smsc911x_reg_write(pdata, INT_EN, temp);
+ spin_unlock_irqrestore(&pdata->int_lock, flags);
smsc911x_reg_write(pdata, INT_STS, INT_STS_SW_INT_);
pdata->software_irq_signal = 1;
smp_wmb();
@@ -1461,9 +1478,11 @@ static irqreturn_t smsc911x_irqhandler(int irq, void *dev_id)
/* Called when there is a multicast update scheduled and
* it is now safe to complete the update */
SMSC_TRACE(INTR, "RX Stop interrupt");
+ spin_lock_irqsave(&pdata->int_lock, flags);
temp = smsc911x_reg_read(pdata, INT_EN);
temp &= (~INT_EN_RXSTOP_INT_EN_);
smsc911x_reg_write(pdata, INT_EN, temp);
+ spin_unlock_irqrestore(&pdata->int_lock, flags);
smsc911x_reg_write(pdata, INT_STS, INT_STS_RXSTOP_INT_);
smsc911x_rx_multicast_update_workaround(pdata);
serviced = IRQ_HANDLED;
@@ -1487,9 +1506,11 @@ static irqreturn_t smsc911x_irqhandler(int irq, void *dev_id)
if (likely(intsts & inten & INT_STS_RSFL_)) {
if (likely(netif_rx_schedule_prep(&pdata->napi))) {
/* Disable Rx interrupts */
+ spin_lock_irqsave(&pdata->int_lock, flags);
temp = smsc911x_reg_read(pdata, INT_EN);
temp &= (~INT_EN_RSFL_EN_);
smsc911x_reg_write(pdata, INT_EN, temp);
+ spin_unlock_irqrestore(&pdata->int_lock, flags);
/* Schedule a NAPI poll */
__netif_rx_schedule(&pdata->napi);
} else {
@@ -1760,6 +1781,7 @@ static int __devinit smsc911x_init(struct net_device *dev)
SMSC_TRACE(PROBE, "PHY will be autodetected.");
spin_lock_init(&pdata->dev_lock);
+ spin_lock_init(&pdata->int_lock);
if (pdata->ioaddr == 0) {
SMSC_WARNING(PROBE, "pdata->ioaddr: 0x00000000");
--
1.6.0.6
--
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