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[Qemu-arm] [PATCH v12 2/9] hw/ptimer: Perform counter wrap around if tim
From: |
Dmitry Osipenko |
Subject: |
[Qemu-arm] [PATCH v12 2/9] hw/ptimer: Perform counter wrap around if timer already expired |
Date: |
Sat, 30 Jan 2016 19:43:11 +0300 |
ptimer_get_count() might be called while QEMU timer already been expired.
In that case ptimer would return counter = 0, which might be undesirable
in case of polled timer. Do counter wrap around for periodic timer to keep
it distributed. In order to achieve more accurate emulation behaviour of
certain hardware, don't perform wrap around when in icount mode and return
counter = 0 in that case (that doesn't affect polled counter distribution).
Signed-off-by: Dmitry Osipenko <address@hidden>
Reviewed-by: Peter Crosthwaite <address@hidden>
---
hw/core/ptimer.c | 19 +++++++++++++------
1 file changed, 13 insertions(+), 6 deletions(-)
diff --git a/hw/core/ptimer.c b/hw/core/ptimer.c
index 5edcd71..d4452d3 100644
--- a/hw/core/ptimer.c
+++ b/hw/core/ptimer.c
@@ -83,14 +83,16 @@ static void ptimer_tick(void *opaque)
uint64_t ptimer_get_count(ptimer_state *s)
{
- int64_t now;
uint64_t counter;
if (s->enabled) {
- now = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
+ int64_t now = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
+ int64_t next = s->next_event;
+ bool expired = (now - next >= 0);
+ bool oneshot = (s->enabled == 2);
+
/* Figure out the current counter value. */
- if (now - s->next_event > 0
- || s->period == 0) {
+ if (s->period == 0 || (expired && (oneshot || use_icount))) {
/* Prevent timer underflowing if it should already have
triggered. */
counter = 0;
@@ -102,7 +104,7 @@ uint64_t ptimer_get_count(ptimer_state *s)
uint32_t period_frac = s->period_frac;
uint64_t period = s->period;
- if ((s->enabled == 1) && !use_icount && (s->delta * period <
10000)) {
+ if (!oneshot && (s->delta * period < 10000) && !use_icount) {
period = 10000 / s->delta;
period_frac = 0;
}
@@ -117,7 +119,7 @@ uint64_t ptimer_get_count(ptimer_state *s)
backwards.
*/
- rem = s->next_event - now;
+ rem = expired ? now - next : next - now;
div = period;
clz1 = clz64(rem);
@@ -137,6 +139,11 @@ uint64_t ptimer_get_count(ptimer_state *s)
div += 1;
}
counter = rem / div;
+
+ if (expired && counter != 0) {
+ /* Wrap around periodic counter. */
+ counter = s->limit - (counter - 1) % s->limit;
+ }
}
} else {
counter = s->delta;
--
2.7.0
- [Qemu-arm] [PATCH v12 0/9] PTimer fixes/features and ARM MPTimer conversion, Dmitry Osipenko, 2016/01/30
- [Qemu-arm] [PATCH v12 2/9] hw/ptimer: Perform counter wrap around if timer already expired,
Dmitry Osipenko <=
- [Qemu-arm] [PATCH v12 1/9] hw/ptimer: Fix issues caused by the adjusted timer limit value, Dmitry Osipenko, 2016/01/30
- [Qemu-arm] [PATCH v12 3/9] hw/ptimer: Update .delta on period/freq change, Dmitry Osipenko, 2016/01/30
- [Qemu-arm] [PATCH v12 4/9] hw/ptimer: Support "on the fly" timer mode switch, Dmitry Osipenko, 2016/01/30
- [Qemu-arm] [PATCH v12 5/9] hw/ptimer: Introduce ptimer_get_limit, Dmitry Osipenko, 2016/01/30
- [Qemu-arm] [PATCH v12 7/9] hw/ptimer: Fix counter - 1 returned by ptimer_get_count for the active timer, Dmitry Osipenko, 2016/01/30
- [Qemu-arm] [PATCH v12 6/9] hw/ptimer: Legalize running with delta = load = 0 and abort on period = 0, Dmitry Osipenko, 2016/01/30
- [Qemu-arm] [PATCH v12 8/9] hw/ptimer: Perform delayed tick instead of immediate if delta = 0, Dmitry Osipenko, 2016/01/30
- [Qemu-arm] [PATCH v12 9/9] arm_mptimer: Convert to use ptimer, Dmitry Osipenko, 2016/01/30