1 files changed, 63 insertions, 0 deletions

diff --git a/drivers/char/hpet.c b/drivers/char/hpet.c
index e7fb0bca3667..c9bf5d44402d 100644
--- a/drivers/char/hpet.c
+++ b/drivers/char/hpet.c
@@ -184,6 +184,67 @@ static irqreturn_t hpet_interrupt(int irq, void *data)
         return IRQ_HANDLED;
 }
 
+static void hpet_timer_set_irq(struct hpet_dev *devp)
+{
+        unsigned long v;
+        int irq, gsi;
+        struct hpet_timer __iomem *timer;
+
+        spin_lock_irq(&hpet_lock);
+        if (devp->hd_hdwirq) {
+                spin_unlock_irq(&hpet_lock);
+                return;
+        }
+
+        timer = devp->hd_timer;
+
+        /* we prefer level triggered mode */
+        v = readl(&timer->hpet_config);
+        if (!(v & Tn_INT_TYPE_CNF_MASK)) {
+                v |= Tn_INT_TYPE_CNF_MASK;
+                writel(v, &timer->hpet_config);
+        }
+        spin_unlock_irq(&hpet_lock);
+
+        v = (readq(&timer->hpet_config) & Tn_INT_ROUTE_CAP_MASK) >>
+                                 Tn_INT_ROUTE_CAP_SHIFT;
+
+        /*
+         * In PIC mode, skip IRQ0-4, IRQ6-9, IRQ12-15 which is always used by
+         * legacy device. In IO APIC mode, we skip all the legacy IRQS.
+         */
+        if (acpi_irq_model == ACPI_IRQ_MODEL_PIC)
+                v &= ~0xf3df;
+        else
+                v &= ~0xffff;
+
+        for (irq = find_first_bit(&v, HPET_MAX_IRQ); irq < HPET_MAX_IRQ;
+                irq = find_next_bit(&v, HPET_MAX_IRQ, 1 + irq)) {
+
+                if (irq >= NR_IRQS) {
+                        irq = HPET_MAX_IRQ;
+                        break;
+                }
+
+                gsi = acpi_register_gsi(irq, ACPI_LEVEL_SENSITIVE,
+                                        ACPI_ACTIVE_LOW);
+                if (gsi > 0)
+                        break;
+
+                /* FIXME: Setup interrupt source table */
+        }
+
+        if (irq < HPET_MAX_IRQ) {
+                spin_lock_irq(&hpet_lock);
+                v = readl(&timer->hpet_config);
+                v |= irq << Tn_INT_ROUTE_CNF_SHIFT;
+                writel(v, &timer->hpet_config);
+                devp->hd_hdwirq = gsi;
+                spin_unlock_irq(&hpet_lock);
+        }
+        return;
+}
+
 static int hpet_open(struct inode *inode, struct file *file)
 {
         struct hpet_dev *devp;
@@ -215,6 +276,8 @@ static int hpet_open(struct inode *inode, struct file *file)
         devp->hd_flags |= HPET_OPEN;
         spin_unlock_irq(&hpet_lock);
 
+        hpet_timer_set_irq(devp);
+
         return 0;
 }