[Qemu-devel] [PATCH v16 07/16] hw/ptimer: Add "continuous trigger" policy

[Dmitry Osipenko]

Currently, periodic timer that has load = delta = 0 performs trigger
on timer reload and stops, printing a "period zero" error message.
Introduce new policy that makes periodic timer to continuously trigger
with a period interval in case of load = 0.

Signed-off-by: Dmitry Osipenko <address@hidden>
---
 hw/core/ptimer.c    | 18 +++++++++++++++++-
 include/hw/ptimer.h |  4 ++++
 2 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/hw/core/ptimer.c b/hw/core/ptimer.c
index e9b2e15..97ce8ae 100644
--- a/hw/core/ptimer.c
+++ b/hw/core/ptimer.c
@@ -45,7 +45,8 @@ static void ptimer_reload(ptimer_state *s, int delta_adjust)
         ptimer_trigger(s);
         delta = s->delta = s->limit;
     }
-    if (delta == 0 || s->period == 0) {
+
+    if (s->period == 0) {
         if (!qtest_enabled()) {
             fprintf(stderr, "Timer with period zero, disabling\n");
         }
@@ -58,6 +59,21 @@ static void ptimer_reload(ptimer_state *s, int delta_adjust)
         delta += delta_adjust;
     }
 
+    if (delta == 0 && (s->policy_mask & PTIMER_POLICY_CONTINUOUS_TRIGGER)) {
+        if (s->enabled == 1) {
+            delta = 1;
+        }
+    }
+
+    if (delta == 0) {
+        if (!qtest_enabled()) {
+            fprintf(stderr, "Timer with delta zero, disabling\n");
+        }
+        timer_del(s->timer);
+        s->enabled = 0;
+        return;
+    }
+
     /*
      * Artificially limit timeout rate to something
      * achievable under QEMU.  Otherwise, QEMU spends all
diff --git a/include/hw/ptimer.h b/include/hw/ptimer.h
index a13a12e..4c9c700 100644
--- a/include/hw/ptimer.h
+++ b/include/hw/ptimer.h
@@ -38,6 +38,10 @@
  * around.  */
 #define PTIMER_POLICY_WRAP_AFTER_ONE_PERIOD (1 << 0)
 
+/* Periodic timer that has load = 0 would continuously re-trigger every
+ * period.  */
+#define PTIMER_POLICY_CONTINUOUS_TRIGGER    (1 << 1)
+
 /* ptimer.c */
 typedef struct ptimer_state ptimer_state;
 typedef void (*ptimer_cb)(void *opaque);
-- 
2.9.3