[PATCH] hpet: allow shared interrupts
This patch adds support for shared HPET interrupts.
The driver previously acknowledged interrupts for both edge and level
interrupts, but didn't actually allow a shared interrupt in the latter case.
We use a new per-timer flag to save whether the timer's interrupt might be
shared, and use it to do the processing required for level interrupts only if
necessary.
Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Acked-by: Bob Picco <bob.picco@hp.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/drivers/char/hpet.c b/drivers/char/hpet.c
index 85d39ff..8e59639f 100644
--- a/drivers/char/hpet.c
+++ b/drivers/char/hpet.c
@@ -90,6 +90,7 @@
#define HPET_OPEN 0x0001
#define HPET_IE 0x0002 /* interrupt enabled */
#define HPET_PERIODIC 0x0004
+#define HPET_SHARED_IRQ 0x0008
#if BITS_PER_LONG == 64
#define write_counter(V, MC) writeq(V, MC)
@@ -120,6 +121,11 @@
unsigned long isr;
devp = data;
+ isr = 1 << (devp - devp->hd_hpets->hp_dev);
+
+ if ((devp->hd_flags & HPET_SHARED_IRQ) &&
+ !(isr & readl(&devp->hd_hpet->hpet_isr)))
+ return IRQ_NONE;
spin_lock(&hpet_lock);
devp->hd_irqdata++;
@@ -137,8 +143,8 @@
&devp->hd_timer->hpet_compare);
}
- isr = (1 << (devp - devp->hd_hpets->hp_dev));
- writeq(isr, &devp->hd_hpet->hpet_isr);
+ if (devp->hd_flags & HPET_SHARED_IRQ)
+ writel(isr, &devp->hd_hpet->hpet_isr);
spin_unlock(&hpet_lock);
spin_lock(&hpet_task_lock);
@@ -375,15 +381,21 @@
}
devp->hd_flags |= HPET_IE;
+
+ if (readl(&timer->hpet_config) & Tn_INT_TYPE_CNF_MASK)
+ devp->hd_flags |= HPET_SHARED_IRQ;
spin_unlock_irq(&hpet_lock);
irq = devp->hd_hdwirq;
if (irq) {
- sprintf(devp->hd_name, "hpet%d", (int)(devp - hpetp->hp_dev));
+ unsigned long irq_flags;
- if (request_irq
- (irq, hpet_interrupt, SA_INTERRUPT, devp->hd_name, (void *)devp)) {
+ sprintf(devp->hd_name, "hpet%d", (int)(devp - hpetp->hp_dev));
+ irq_flags = devp->hd_flags & HPET_SHARED_IRQ
+ ? SA_SHIRQ : SA_INTERRUPT;
+ if (request_irq(irq, hpet_interrupt, irq_flags,
+ devp->hd_name, (void *)devp)) {
printk(KERN_ERR "hpet: IRQ %d is not free\n", irq);
irq = 0;
}
@@ -417,8 +429,10 @@
write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
}
- isr = (1 << (devp - hpets->hp_dev));
- writeq(isr, &hpet->hpet_isr);
+ if (devp->hd_flags & HPET_SHARED_IRQ) {
+ isr = 1 << (devp - hpets->hp_dev);
+ writel(isr, &hpet->hpet_isr);
+ }
writeq(g, &timer->hpet_config);
local_irq_restore(flags);