1 files changed, 43 insertions, 15 deletions

diff --git a/hw/core/ptimer.c b/hw/core/ptimer.c
index c45c835a17..1f4122da4e 100644
--- a/hw/core/ptimer.c
+++ b/hw/core/ptimer.c
@@ -13,6 +13,8 @@
 #include "sysemu/replay.h"
 #include "sysemu/qtest.h"
 
+#define DELTA_ADJUST    1
+
 struct ptimer_state
 {
     uint8_t enabled; /* 0 = disabled, 1 = periodic, 2 = oneshot.  */
@@ -35,16 +37,17 @@ static void ptimer_trigger(ptimer_state *s)
     }
 }
 
-static void ptimer_reload(ptimer_state *s)
+static void ptimer_reload(ptimer_state *s, int delta_adjust)
 {
     uint32_t period_frac = s->period_frac;
     uint64_t period = s->period;
+    uint64_t delta = s->delta;
 
-    if (s->delta == 0) {
+    if (delta == 0) {
         ptimer_trigger(s);
-        s->delta = s->limit;
+        delta = s->delta = s->limit;
     }
-    if (s->delta == 0 || s->period == 0) {
+    if (delta == 0 || s->period == 0) {
         if (!qtest_enabled()) {
             fprintf(stderr, "Timer with period zero, disabling\n");
         }
@@ -53,6 +56,10 @@ static void ptimer_reload(ptimer_state *s)
         return;
     }
 
+    if (s->policy_mask & PTIMER_POLICY_WRAP_AFTER_ONE_PERIOD) {
+        delta += delta_adjust;
+    }
+
     /*
      * Artificially limit timeout rate to something
      * achievable under QEMU.  Otherwise, QEMU spends all
@@ -62,15 +69,15 @@ static void ptimer_reload(ptimer_state *s)
      * on the current generation of host machines.
      */
 
-    if (s->enabled == 1 && (s->delta * period < 10000) && !use_icount) {
-        period = 10000 / s->delta;
+    if (s->enabled == 1 && (delta * period < 10000) && !use_icount) {
+        period = 10000 / delta;
         period_frac = 0;
     }
 
     s->last_event = s->next_event;
-    s->next_event = s->last_event + s->delta * period;
+    s->next_event = s->last_event + delta * period;
     if (period_frac) {
-        s->next_event += ((int64_t)period_frac * s->delta) >> 32;
+        s->next_event += ((int64_t)period_frac * delta) >> 32;
     }
     timer_mod(s->timer, s->next_event);
 }
@@ -83,7 +90,7 @@ static void ptimer_tick(void *opaque)
     if (s->enabled == 2) {
         s->enabled = 0;
     } else {
-        ptimer_reload(s);
+        ptimer_reload(s, DELTA_ADJUST);
     }
 }
 
@@ -94,6 +101,7 @@ 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);
 
@@ -118,7 +126,7 @@ uint64_t ptimer_get_count(ptimer_state *s)
             /* We need to divide time by period, where time is stored in
                rem (64-bit integer) and period is stored in period/period_frac
                (64.32 fixed point).
-              
+
                Doing full precision division is hard, so scale values and
                do a 64-bit division.  The result should be rounded down,
                so that the rounding error never causes the timer to go
@@ -145,6 +153,26 @@ uint64_t ptimer_get_count(ptimer_state *s)
                     div += 1;
             }
             counter = rem / div;
+
+            if (s->policy_mask & PTIMER_POLICY_WRAP_AFTER_ONE_PERIOD) {
+                /* Before wrapping around, timer should stay with counter = 0
+                   for a one period.  */
+                if (!oneshot && s->delta == s->limit) {
+                    if (now == last) {
+                        /* Counter == delta here, check whether it was
+                           adjusted and if it was, then right now it is
+                           that "one period".  */
+                        if (counter == s->limit + DELTA_ADJUST) {
+                            return 0;
+                        }
+                    } else if (counter == s->limit) {
+                        /* Since the counter is rounded down and now != last,
+                           the counter == limit means that delta was adjusted
+                           by +1 and right now it is that adjusted period.  */
+                        return 0;
+                    }
+                }
+            }
         }
     } else {
         counter = s->delta;
@@ -157,7 +185,7 @@ void ptimer_set_count(ptimer_state *s, uint64_t count)
     s->delta = count;
     if (s->enabled) {
         s->next_event = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
-        ptimer_reload(s);
+        ptimer_reload(s, 0);
     }
 }
 
@@ -174,7 +202,7 @@ void ptimer_run(ptimer_state *s, int oneshot)
     s->enabled = oneshot ? 2 : 1;
     if (was_disabled) {
         s->next_event = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
-        ptimer_reload(s);
+        ptimer_reload(s, 0);
     }
 }
 
@@ -198,7 +226,7 @@ void ptimer_set_period(ptimer_state *s, int64_t period)
     s->period_frac = 0;
     if (s->enabled) {
         s->next_event = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
-        ptimer_reload(s);
+        ptimer_reload(s, 0);
     }
 }
 
@@ -210,7 +238,7 @@ void ptimer_set_freq(ptimer_state *s, uint32_t freq)
     s->period_frac = (1000000000ll << 32) / freq;
     if (s->enabled) {
         s->next_event = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
-        ptimer_reload(s);
+        ptimer_reload(s, 0);
     }
 }
 
@@ -223,7 +251,7 @@ void ptimer_set_limit(ptimer_state *s, uint64_t limit, int reload)
         s->delta = limit;
     if (s->enabled && reload) {
         s->next_event = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
-        ptimer_reload(s);
+        ptimer_reload(s, 0);
     }
 }