[v15,02/15] hw/ptimer: Fix counter - 1 returned by ptimer_get_count for the active timer

Commit Message

Dmitry Osipenko July 21, 2016, 2:31 p.m. UTC

Due to rounding down performed by ptimer_get_count, it returns counter - 1 for
the enabled timer. That's incorrect because counter should decrement only after
period been expired, not before. I.e. if running timer has been loaded with
value X, then timer counter should stay with X until period expired.
Fix this by adding 1 to the counter value.

Signed-off-by: Dmitry Osipenko <[e-mail]>
---
 hw/core/ptimer.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

Patch

diff --git a/hw/core/ptimer.c b/hw/core/ptimer.c
index 9dc2bb0..461b91c 100644
--- a/hw/core/ptimer.c
+++ b/hw/core/ptimer.c
@@ -89,6 +89,7 @@  uint64_t ptimer_get_count(ptimer_state *s)
     if (s->enabled) {
         int64_t now = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
         int64_t next = s->next_event;
+        int64_t last = s->last_event;
         bool expired = (now - next >= 0);
         bool oneshot = (s->enabled == 2);
 
@@ -97,6 +98,8 @@  uint64_t ptimer_get_count(ptimer_state *s)
             /* Prevent timer underflowing if it should already have
                triggered.  */
             counter = 1;
+        } else if (now == last) {
+            counter = s->delta;
         } else {
             uint64_t rem;
             uint64_t div;
@@ -139,7 +142,7 @@  uint64_t ptimer_get_count(ptimer_state *s)
                 if ((uint32_t)(period_frac << shift))
                     div += 1;
             }
-            counter = rem / div;
+            counter = rem / div + 1;
         }
     } else {
         counter = s->delta;