This patch is supposed to heavily increase overall system
vitality. It reduces the time periodic work in the bcm43xx driver
is run, with IRQs disabled, from several msecs to a few usecs.
I am not sure, if we still want to have this in 2.6.17, as
it is not a crash fix or something. But it fixes "lost interrupt"
problems for some people.
I would like to get this into wireless-2.6, but before that
happens I would like to have a few regression tests by people.
Please apply this and run high network traffic for 10-15 minutes.
Please enable kernel spinlock lockup and recursion detection
while testing.
--
Enable local CPU IRQs while executing periodic work handlers.
Periodic work handlers may take a long time to execute,
so disabling IRQs for the whole time is a bad idea.
This patch disables and synchronizes all bcm43xx IRQs on
periodic work entry and re-enables CPU IRQs afterwards.
It still tempoarly disables CPU IRQs while measuring the
deviation value, as I have the feeling that this is time
critical and may not be interrupted. This causes IRQs to be
disabled for about 35usecs. I hope that does not hurt.
This is an attempt to reduce system IRQ pressure and avoid
lost IRQs in other devices.
Signed-off-by: Michael Buesch <[EMAIL PROTECTED]>
Index: wireless-dev/drivers/net/wireless/bcm43xx/bcm43xx.h
===================================================================
--- wireless-dev.orig/drivers/net/wireless/bcm43xx/bcm43xx.h 2006-05-22
13:32:34.000000000 +0200
+++ wireless-dev/drivers/net/wireless/bcm43xx/bcm43xx.h 2006-05-22
14:14:18.000000000 +0200
@@ -647,9 +647,7 @@
void __iomem *mmio_addr;
unsigned int mmio_len;
- /* Do not use the lock directly. Use the bcm43xx_lock* helper
- * functions, to be MMIO-safe. */
- spinlock_t _lock;
+ spinlock_t lock;
/* Driver status flags. */
u32 initialized:1, /* init_board() succeed */
@@ -753,8 +751,8 @@
* the *_mmio lock functions.
* MMIO read-access is allowed, though.
*/
-#define bcm43xx_lock(bcm, flags) spin_lock_irqsave(&(bcm)->_lock, flags)
-#define bcm43xx_unlock(bcm, flags) spin_unlock_irqrestore(&(bcm)->_lock,
flags)
+#define bcm43xx_lock(bcm, flags) spin_lock_irqsave(&(bcm)->lock, flags)
+#define bcm43xx_unlock(bcm, flags) spin_unlock_irqrestore(&(bcm)->lock,
flags)
/* bcm43xx_(un)lock_mmio() protect struct bcm43xx_private and MMIO.
* MMIO write-access to the device is allowed.
* All MMIO writes are flushed on unlock, so it is guaranteed to not
Index: wireless-dev/drivers/net/wireless/bcm43xx/bcm43xx_main.c
===================================================================
--- wireless-dev.orig/drivers/net/wireless/bcm43xx/bcm43xx_main.c
2006-05-22 13:32:34.000000000 +0200
+++ wireless-dev/drivers/net/wireless/bcm43xx/bcm43xx_main.c 2006-05-22
14:40:08.000000000 +0200
@@ -496,20 +496,34 @@
return old_mask;
}
-/* Make sure we don't receive more data from the device. */
+/* Disable IRQs on the device and make sure no IRQ handler
+ * (or tasklet) is running on return.
+ */
static int bcm43xx_disable_interrupts_sync(struct bcm43xx_private *bcm, u32
*oldstate)
{
u32 old;
unsigned long flags;
+ unsigned int irq;
bcm43xx_lock_mmio(bcm, flags);
- if (bcm43xx_is_initializing(bcm) || bcm->shutting_down) {
+ if (unlikely(bcm43xx_is_initializing(bcm) ||
+ bcm->shutting_down)) {
bcm43xx_unlock_mmio(bcm, flags);
return -EBUSY;
}
+ irq = bcm->irq;
old = bcm43xx_interrupt_disable(bcm, BCM43xx_IRQ_ALL);
- tasklet_disable(&bcm->isr_tasklet);
+
+ /* Unlock, so running IRQ handlers or tasklets can return
+ * and don't deadlock.
+ * The access of isr_tasklet after unlocking is Ok, because
+ * it can not race after synchronizing IRQ.
+ */
bcm43xx_unlock_mmio(bcm, flags);
+
+ synchronize_irq(irq);
+ tasklet_disable(&bcm->isr_tasklet);
+
if (oldstate)
*oldstate = old;
@@ -1860,7 +1874,7 @@
if (!bcm)
return IRQ_NONE;
- spin_lock(&bcm->_lock);
+ spin_lock(&bcm->lock);
reason = bcm43xx_read32(bcm, BCM43xx_MMIO_GEN_IRQ_REASON);
if (reason == 0xffffffff) {
@@ -1899,7 +1913,7 @@
out:
mmiowb();
- spin_unlock(&bcm->_lock);
+ spin_unlock(&bcm->lock);
return ret;
}
@@ -3101,8 +3115,19 @@
struct bcm43xx_private *bcm = (struct bcm43xx_private *)d;
unsigned long flags;
unsigned int state;
+ u32 savedirqs;
+ int err;
- bcm43xx_lock_mmio(bcm, flags);
+ err = bcm43xx_disable_interrupts_sync(bcm, &savedirqs);
+ assert(!err);
+ /* Periodic work can take a long time so we don't want
+ * to disable IRQs on the CPU.
+ * spin_lock() is deadlock safe here, because we previously
+ * disabled and synced IRQs on the device. No IRQ is supposed
+ * to happen before bcm43xx_interrupt_enable(), so it
+ * can't deadlock with the spin_lock in the IRQ handler.
+ */
+ spin_lock(&bcm->lock);
assert(bcm->initialized);
state = bcm->periodic_state;
@@ -3117,7 +3142,12 @@
mod_timer(&bcm->periodic_tasks, jiffies + (HZ * 15));
- bcm43xx_unlock_mmio(bcm, flags);
+ local_irq_save(flags);
+ bcm43xx_interrupt_enable(bcm, savedirqs);
+ tasklet_enable(&bcm->isr_tasklet);
+ mmiowb();
+ spin_unlock(&bcm->lock);
+ local_irq_restore(flags);
}
static void bcm43xx_periodic_tasks_delete(struct bcm43xx_private *bcm)
@@ -3678,9 +3708,11 @@
static int bcm43xx_net_stop(struct net_device *net_dev)
{
struct bcm43xx_private *bcm = bcm43xx_priv(net_dev);
+ int err;
ieee80211softmac_stop(net_dev);
- bcm43xx_disable_interrupts_sync(bcm, NULL);
+ err = bcm43xx_disable_interrupts_sync(bcm, NULL);
+ assert(!err);
bcm43xx_free_board(bcm);
return 0;
@@ -3700,7 +3732,7 @@
bcm->pci_dev = pci_dev;
bcm->net_dev = net_dev;
bcm->bad_frames_preempt = modparam_bad_frames_preempt;
- spin_lock_init(&bcm->_lock);
+ spin_lock_init(&bcm->lock);
tasklet_init(&bcm->isr_tasklet,
(void (*)(unsigned long))bcm43xx_interrupt_tasklet,
(unsigned long)bcm);
Index: wireless-dev/drivers/net/wireless/bcm43xx/bcm43xx_phy.c
===================================================================
--- wireless-dev.orig/drivers/net/wireless/bcm43xx/bcm43xx_phy.c
2006-05-22 13:32:34.000000000 +0200
+++ wireless-dev/drivers/net/wireless/bcm43xx/bcm43xx_phy.c 2006-05-22
14:20:57.000000000 +0200
@@ -1410,7 +1410,10 @@
u16 bcm43xx_phy_lo_g_deviation_subval(struct bcm43xx_private *bcm, u16 control)
{
struct bcm43xx_phyinfo *phy = bcm43xx_current_phy(bcm);
+ u16 ret;
+ unsigned long flags;
+ local_irq_save(flags);
if (phy->connected) {
bcm43xx_phy_write(bcm, 0x15, 0xE300);
control <<= 8;
@@ -1430,8 +1433,10 @@
bcm43xx_phy_write(bcm, 0x0015, control | 0xFFE0);
udelay(8);
}
+ ret = bcm43xx_phy_read(bcm, 0x002D);
+ local_irq_restore(flags);
- return bcm43xx_phy_read(bcm, 0x002D);
+ return ret;
}
static u32 bcm43xx_phy_lo_g_singledeviation(struct bcm43xx_private *bcm, u16
control)
-
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