Re: [PATCH] x86: Get irq for hpet timer

[Kevin Hao]

On Fri, 2008-05-16 at 10:46 +0200, Clemens Ladisch wrote:
> Kevin Hao wrote:
> > HPET timer's IRQ is 0 by default, so we have to select which irq
> > will be used for these timers. We wait to set the timer's irq until
> > we really turn on interrupt in order to reduce the chance of
> > conflicting with some legacy device.
> >
> > +	for (irq = find_first_bit(&cap, HPET_MAX_IRQ); irq < HPET_MAX_IRQ;
> > +		irq = find_next_bit(&cap, HPET_MAX_IRQ, 1 + irq)) {
> > +		if (request_irq(irq, hpet_interrupt, irq_flags,
> > +				devp->hd_name, (void *)devp)) {
> > +			printk(KERN_WARNING "hpet: IRQ %d is not free\n", irq);
> > +			continue;
> 
> This warning message will be output for every interrupt that is in use
> by another device.  I think it would be better to postpone complaining
> until after the loop, if no interrupt has been found at all.
> 

Ok, I agree with you.
This is the revised version.

Best Regards,
Kevin
---
 drivers/char/hpet.c  |   63 ++++++++++++++++++++++++++++++++++++++------------
 include/linux/hpet.h |    3 +-
 2 files changed, 50 insertions(+), 16 deletions(-)

diff --git a/drivers/char/hpet.c b/drivers/char/hpet.c
index e7fb0bc..0fdc627 100644
--- a/drivers/char/hpet.c
+++ b/drivers/char/hpet.c
@@ -383,6 +383,52 @@ hpet_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
 	return hpet_ioctl_common(devp, cmd, arg, 0);
 }
 
+static int hpet_timer_get_irq(struct hpet_dev *devp)
+{
+	struct hpet_timer __iomem *timer;
+	struct hpet __iomem *hpet;
+	struct hpets *hpetp;
+	unsigned long cap, irq_flags;
+	int irq;
+
+	timer = devp->hd_timer;
+	hpet = devp->hd_hpet;
+	hpetp = devp->hd_hpets;
+
+	irq = devp->hd_hdwirq;
+
+	sprintf(devp->hd_name, "hpet%d", (int)(devp - hpetp->hp_dev));
+	irq_flags = devp->hd_flags & HPET_SHARED_IRQ
+					? IRQF_SHARED : IRQF_DISABLED;
+	if (irq) {
+		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;
+		}
+		return irq;
+	}
+
+	cap = (readq(&timer->hpet_config) & Tn_INT_ROUTE_CAP_MASK)
+				 >> Tn_INT_ROUTE_CAP_SHIFT;
+
+	for (irq = find_first_bit(&cap, HPET_MAX_IRQ); irq < HPET_MAX_IRQ;
+		irq = find_next_bit(&cap, HPET_MAX_IRQ, 1 + irq)) {
+		if (request_irq(irq, hpet_interrupt, irq_flags,
+				devp->hd_name, (void *)devp))
+			continue;
+		break;
+	}
+
+	if  (irq >= HPET_MAX_IRQ) {
+		printk(KERN_WARNING "hpet: No available IRQ for %s timer\n",
+			devp->hd_name);
+		irq = 0;
+	}
+
+	return irq;
+}
+
 static int hpet_ioctl_ieon(struct hpet_dev *devp)
 {
 	struct hpet_timer __iomem *timer;
@@ -412,21 +458,7 @@ static int hpet_ioctl_ieon(struct hpet_dev *devp)
 		devp->hd_flags |= HPET_SHARED_IRQ;
 	spin_unlock_irq(&hpet_lock);
 
-	irq = devp->hd_hdwirq;
-
-	if (irq) {
-		unsigned long irq_flags;
-
-		sprintf(devp->hd_name, "hpet%d", (int)(devp - hpetp->hp_dev));
-		irq_flags = devp->hd_flags & HPET_SHARED_IRQ
-						? IRQF_SHARED : IRQF_DISABLED;
-		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;
-		}
-	}
-
+	irq = hpet_timer_get_irq(devp);
 	if (irq == 0) {
 		spin_lock_irq(&hpet_lock);
 		devp->hd_flags ^= HPET_IE;
@@ -438,6 +470,7 @@ static int hpet_ioctl_ieon(struct hpet_dev *devp)
 	t = devp->hd_ireqfreq;
 	v = readq(&timer->hpet_config);
 	g = v | Tn_INT_ENB_CNF_MASK;
+	g |= irq << Tn_INT_ROUTE_CNF_SHIFT;
 
 	if (devp->hd_flags & HPET_PERIODIC) {
 		write_counter(t, &timer->hpet_compare);
diff --git a/include/linux/hpet.h b/include/linux/hpet.h
index 2dc29ce..440ca72 100644
--- a/include/linux/hpet.h
+++ b/include/linux/hpet.h
@@ -37,6 +37,7 @@ struct hpet {
 #define	hpet_compare	_u1._hpet_compare
 
 #define	HPET_MAX_TIMERS	(32)
+#define HPET_MAX_IRQ	(32)
 
 /*
  * HPET general capabilities register
@@ -64,7 +65,7 @@ struct hpet {
  */
 
 #define	Tn_INT_ROUTE_CAP_MASK		(0xffffffff00000000ULL)
-#define	Tn_INI_ROUTE_CAP_SHIFT		(32UL)
+#define	Tn_INT_ROUTE_CAP_SHIFT		(32UL)
 #define	Tn_FSB_INT_DELCAP_MASK		(0x8000UL)
 #define	Tn_FSB_INT_DELCAP_SHIFT		(15)
 #define	Tn_FSB_EN_CNF_MASK		(0x4000UL)

> 
> Regards,
> Clemens
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