qemu-devel
[Top][All Lists]
Advanced

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

[Qemu-devel] [PATCH 2/2] hpet: inverse polarity when pin above ISA_NUM_I


From: Liu Ping Fan
Subject: [Qemu-devel] [PATCH 2/2] hpet: inverse polarity when pin above ISA_NUM_IRQS
Date: Sun, 25 Aug 2013 10:16:24 +0800

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.(And this is observed on
bare metal).

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

Signed-off-by: Liu Ping Fan <address@hidden>
---
kernel has a bug with ioapic, refer to
   https://lkml.org/lkml/2013/8/23/98
With all these patch, linux-2.6/Documentation/timers/hpet_example.c can work
on qemu 
---
 hw/timer/hpet.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/hw/timer/hpet.c b/hw/timer/hpet.c
index cd95d39..a6626e2 100644
--- a/hw/timer/hpet.c
+++ b/hw/timer/hpet.c
@@ -200,13 +200,23 @@ 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]);
-- 
1.8.1.4




reply via email to

[Prev in Thread] Current Thread [Next in Thread]