[Qemu-devel] [PATCH v15 12/15] hw/ptimer: Add "no immediate reload" policy

[Dmitry Osipenko]

Immediate counter re-load on setting (or on starting to run with)
counter = 0 is a wrong behaviour for some of the timers. Add "no
immediate reload" policy that provides correct behaviour for such timers.

Signed-off-by: Dmitry Osipenko <dig...@gmail.com>
---
 hw/core/ptimer.c    | 8 +++++---
 include/hw/ptimer.h | 2 ++
 2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/hw/core/ptimer.c b/hw/core/ptimer.c
index d37e8ab..7747c65 100644
--- a/hw/core/ptimer.c
+++ b/hw/core/ptimer.c
@@ -44,7 +44,7 @@ static void ptimer_reload(ptimer_state *s, int delta_adjust)
         ptimer_trigger(s);
     }
 
-    if (delta == 0) {
+    if (delta == 0 && !(s->policy_mask & PTIMER_POLICY_NO_IMMEDIATE_RELOAD)) {
         delta = s->delta = s->limit;
     }
 
@@ -102,11 +102,13 @@ static void ptimer_tick(void *opaque)
 {
     ptimer_state *s = (ptimer_state *)opaque;
     ptimer_trigger(s);
-    s->delta = 0;
     if (s->enabled == 2) {
+        s->delta = 0;
         s->enabled = 0;
     } else {
-        ptimer_reload(s, 1);
+        int delta_adjust = (s->delta != 0 && s->limit != 0) ? 1 : 0;
+        s->delta = s->limit;
+        ptimer_reload(s, delta_adjust);
     }
 }
 
diff --git a/include/hw/ptimer.h b/include/hw/ptimer.h
index ec76183..3e49550 100644
--- a/include/hw/ptimer.h
+++ b/include/hw/ptimer.h
@@ -22,6 +22,8 @@
 /* Starting to run with/setting counter = 0 won't perform immediate
  * trigger.  */
 #define PTIMER_POLICY_NO_IMMEDIATE_TRIGGER  (1 << 2)
+/* Starting to run with/setting counter = 0 won't re-load counter.  */
+#define PTIMER_POLICY_NO_IMMEDIATE_RELOAD   (1 << 3)
 
 /* ptimer.c */
 typedef struct ptimer_state ptimer_state;
-- 
2.9.2