[Qemu-devel] [PATCH] Sun4m : Timer RUN/STOP bit.

[Olivier Danet <odanet@caramail.com>]

The Sun4m architecture has one 'system' timer and one timer per CPU.
The CPU timers can be configured in two modes :
* 22bits Counter/Timer. Periodic interrupts.
* 54bits User timer. For profiling. In this mode, the Run/Stop bit
   controls the timer.

The run/stop bit controls the timer only when it is in "User" mode, but
its state shall be persistent.

Signed-off-by: Olivier Danet <odanet@caramail.com>
---
  hw/timer/slavio_timer.c | 25 ++++++++++---------------
  1 file changed, 10 insertions(+), 15 deletions(-)

diff --git a/hw/timer/slavio_timer.c b/hw/timer/slavio_timer.c
index f75b914..e4dccea 100644
--- a/hw/timer/slavio_timer.c
+++ b/hw/timer/slavio_timer.c
@@ -51,7 +51,7 @@ typedef struct CPUTimerState {
      ptimer_state *timer;
      uint32_t count, counthigh, reached;
      /* processor only */
-    uint32_t running;
+    uint32_t run;
      uint64_t limit;
  } CPUTimerState;

@@ -177,7 +177,7 @@ static uint64_t slavio_timer_mem_readl(void *opaque, 
hwaddr addr,
          // only available in processor counter/timer
          // read start/stop status
          if (timer_index > 0) {
-            ret = t->running;
+            ret = t->run;
          } else {
              ret = 0;
          }
@@ -260,16 +260,15 @@ static void slavio_timer_mem_writel(void *opaque, 
hwaddr addr,
      case TIMER_STATUS:
          if (slavio_timer_is_user(tc)) {
              // start/stop user counter
-            if ((val & 1) && !t->running) {
+            if (val & 1) {
trace_slavio_timer_mem_writel_status_start(timer_index);
                  ptimer_run(t->timer, 0);
-                t->running = 1;
-            } else if (!(val & 1) && t->running) {
+            } else {
trace_slavio_timer_mem_writel_status_stop(timer_index);
                  ptimer_stop(t->timer);
-                t->running = 0;
              }
          }
+        t->run = val & 1;
          break;
      case TIMER_MODE:
          if (timer_index == 0) {
@@ -284,8 +283,9 @@ static void slavio_timer_mem_writel(void *opaque, 
hwaddr addr,
                      if (val & processor) { // counter -> user timer
                          qemu_irq_lower(curr_timer->irq);
                          // counters are always running
-                        ptimer_stop(curr_timer->timer);
-                        curr_timer->running = 0;
+                        if (!curr_timer->run) {
+                            ptimer_stop(curr_timer->timer);
+                        }
                          // user timer limit is always the same
                          curr_timer->limit = TIMER_MAX_COUNT64;
                          ptimer_set_limit(curr_timer->timer,
@@ -296,13 +296,8 @@ static void slavio_timer_mem_writel(void *opaque, 
hwaddr addr,
                          s->cputimer_mode |= processor;
trace_slavio_timer_mem_writel_mode_user(timer_index);
                      } else { // user timer -> counter
-                        // stop the user timer if it is running
-                        if (curr_timer->running) {
-                            ptimer_stop(curr_timer->timer);
-                        }
                          // start the counter
                          ptimer_run(curr_timer->timer, 0);
-                        curr_timer->running = 1;
                          // clear this processors user timer bit in config
                          // register
                          s->cputimer_mode &= ~processor;
@@ -340,7 +335,7 @@ static const VMStateDescription vmstate_timer = {
          VMSTATE_UINT32(count, CPUTimerState),
          VMSTATE_UINT32(counthigh, CPUTimerState),
          VMSTATE_UINT32(reached, CPUTimerState),
-        VMSTATE_UINT32(running, CPUTimerState),
+        VMSTATE_UINT32(run    , CPUTimerState),
          VMSTATE_PTIMER(timer, CPUTimerState),
          VMSTATE_END_OF_LIST()
      }
@@ -373,7 +368,7 @@ static void slavio_timer_reset(DeviceState *d)
              ptimer_set_limit(curr_timer->timer,
                               LIMIT_TO_PERIODS(TIMER_MAX_COUNT32), 1);
              ptimer_run(curr_timer->timer, 0);
-            curr_timer->running = 1;
+            curr_timer->run = 1;
          }
      }
      s->cputimer_mode = 0;
-- 
1.8.1.5