diff mbox

[PULL,21/28] hpet: inverse polarity when pin above ISA_NUM_IRQS

Message ID 1386786509-29966-21-git-send-email-mst@redhat.com
State New
Headers show

Commit Message

Michael S. Tsirkin Dec. 11, 2013, 6:31 p.m. UTC 
From: Liu Ping Fan <qemulist@gmail.com>

According to hpet spec, hpet irq is high active. But according to
ICH spec, there is inversion before the input of ioapic. So the OS
will expect low active on this IRQ line. (On bare metal, if OS driver
claims high active on this line, spurious irq is generated)

We fold the emulation of this inversion inside the hpet logic.

Signed-off-by: Liu Ping Fan <pingfank@linux.vnet.ibm.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 hw/timer/hpet.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)
diff mbox

Patch

diff --git a/hw/timer/hpet.c b/hw/timer/hpet.c
index 2eb75ea..0aee2c1 100644
--- a/hw/timer/hpet.c
+++ b/hw/timer/hpet.c
@@ -198,13 +198,23 @@  static void update_irq(struct HPETTimer *timer, int set)
     if (!set || !timer_enabled(timer) || !hpet_enabled(timer->state)) {
         s->isr &= ~mask;
         if (!timer_fsb_route(timer)) {
-            qemu_irq_lower(s->irqs[route]);
+            /* fold the ICH PIRQ# pin's internal inversion logic into hpet */
+            if (route >= ISA_NUM_IRQS) {
+                qemu_irq_raise(s->irqs[route]);
+            } else {
+                qemu_irq_lower(s->irqs[route]);
+            }
         }
     } else if (timer_fsb_route(timer)) {
         stl_le_phys(timer->fsb >> 32, timer->fsb & 0xffffffff);
     } else if (timer->config & HPET_TN_TYPE_LEVEL) {
         s->isr |= mask;
-        qemu_irq_raise(s->irqs[route]);
+        /* fold the ICH PIRQ# pin's internal inversion logic into hpet */
+        if (route >= ISA_NUM_IRQS) {
+            qemu_irq_lower(s->irqs[route]);
+        } else {
+            qemu_irq_raise(s->irqs[route]);
+        }
     } else {
         s->isr &= ~mask;
         qemu_irq_pulse(s->irqs[route]);