aboutsummaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorPeter Maydell <peter.maydell@linaro.org>2018-07-09 14:51:34 +0100
committerPeter Maydell <peter.maydell@linaro.org>2018-07-09 14:51:34 +0100
commit1a9b30646edd8d10caaa9727611750bf57d08c74 (patch)
tree06d6df51b6baf6dcdefd48c8635cb535284b27d2
parent0e256833085cc9d292e59a5bda9b886fd09a5f83 (diff)
downloadqemu-arm-1a9b30646edd8d10caaa9727611750bf57d08c74.tar.gz
hw/timer/cmsdk-apb-timer: run or stop timer on writes to RELOAD and VALUE
If the CMSDK APB timer is set up with a zero RELOAD value then it will count down to zero, fire once and then stay at zero. From the point of view of the ptimer system, the timer is disabled; but the enable bit in the CTRL register is still set and if the guest subsequently writes to the RELOAD or VALUE registers this should cause the timer to start counting down again. Add code to the write paths for RELOAD and VALUE so that we correctly restart the timer in this situation. Conversely, if the new RELOAD and VALUE are both zero, we should stop the ptimer. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Tested-by: Guenter Roeck <linux@roeck-us.net> Message-id: 20180703171044.9503-5-peter.maydell@linaro.org
-rw-r--r--hw/timer/cmsdk-apb-timer.c16
1 files changed, 16 insertions, 0 deletions
diff --git a/hw/timer/cmsdk-apb-timer.c b/hw/timer/cmsdk-apb-timer.c
index 3ebdc7be40..801d1dba74 100644
--- a/hw/timer/cmsdk-apb-timer.c
+++ b/hw/timer/cmsdk-apb-timer.c
@@ -126,10 +126,26 @@ static void cmsdk_apb_timer_write(void *opaque, hwaddr offset, uint64_t value,
break;
case A_RELOAD:
/* Writing to reload also sets the current timer value */
+ if (!value) {
+ ptimer_stop(s->timer);
+ }
ptimer_set_limit(s->timer, value, 1);
+ if (value && (s->ctrl & R_CTRL_EN_MASK)) {
+ /*
+ * Make sure timer is running (it might have stopped if this
+ * was an expired one-shot timer)
+ */
+ ptimer_run(s->timer, 0);
+ }
break;
case A_VALUE:
+ if (!value && !ptimer_get_limit(s->timer)) {
+ ptimer_stop(s->timer);
+ }
ptimer_set_count(s->timer, value);
+ if (value && (s->ctrl & R_CTRL_EN_MASK)) {
+ ptimer_run(s->timer, ptimer_get_limit(s->timer) == 0);
+ }
break;
case A_INTSTATUS:
/* Just one bit, which is W1C. */