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[Qemu-arm] [PATCH v11 2/7] hw/ptimer: Perform counter wrap around if tim
From: |
Dmitry Osipenko |
Subject: |
[Qemu-arm] [PATCH v11 2/7] hw/ptimer: Perform counter wrap around if timer already expired |
Date: |
Thu, 21 Jan 2016 22:03:45 +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>
---
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 6dc1677..cb50d30 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 % s->limit;
+ }
}
} else {
counter = s->delta;
--
2.7.0
- [Qemu-arm] [PATCH v11 0/7] PTimer fixes/features and ARM MPTimer conversion, Dmitry Osipenko, 2016/01/21
- [Qemu-arm] [PATCH v11 3/7] hw/ptimer: Update .delta on period/freq change, Dmitry Osipenko, 2016/01/21
- [Qemu-arm] [PATCH v11 4/7] hw/ptimer: Support "on the fly" timer mode switch, Dmitry Osipenko, 2016/01/21
- [Qemu-arm] [PATCH v11 2/7] hw/ptimer: Perform counter wrap around if timer already expired,
Dmitry Osipenko <=
- [Qemu-arm] [PATCH v11 1/7] hw/ptimer: Fix issues caused by the adjusted timer limit value, Dmitry Osipenko, 2016/01/21
- [Qemu-arm] [PATCH v11 6/7] hw/ptimer: Legalize running with delta = load = 0 and abort on period = 0, Dmitry Osipenko, 2016/01/21
- [Qemu-arm] [PATCH v11 7/7] arm_mptimer: Convert to use ptimer, Dmitry Osipenko, 2016/01/21