target-arm: Add trace events for the generic timers

Add some useful trace events for the ARM generic timers (notably
the various register writes and the resulting IRQ line state).

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
Message-id: 1476294876-12340-3-git-send-email-peter.maydell@linaro.org

2 files changed, 26 insertions, 4 deletions

diff --git a/target-arm/helper.c b/target-arm/helper.c
index a65f4f2..cb83ee2 100644
--- a/target-arm/helper.c
+++ b/target-arm/helper.c
@@ -1,4 +1,5 @@
 #include "qemu/osdep.h"
+#include "trace.h"
 #include "cpu.h"
 #include "internals.h"
 #include "exec/gdbstub.h"
@@ -1560,10 +1561,13 @@ static void gt_recalc_timer(ARMCPU *cpu, int timeridx)
         /* Note that this must be unsigned 64 bit arithmetic: */
         int istatus = count - offset >= gt->cval;
         uint64_t nexttick;
+        int irqstate;
 
         gt->ctl = deposit32(gt->ctl, 2, 1, istatus);
-        qemu_set_irq(cpu->gt_timer_outputs[timeridx],
-                     (istatus && !(gt->ctl & 2)));
+
+        irqstate = (istatus && !(gt->ctl & 2));
+        qemu_set_irq(cpu->gt_timer_outputs[timeridx], irqstate);
+
         if (istatus) {
             /* Next transition is when count rolls back over to zero */
             nexttick = UINT64_MAX;
@@ -1580,11 +1584,13 @@ static void gt_recalc_timer(ARMCPU *cpu, int timeridx)
             nexttick = INT64_MAX / GTIMER_SCALE;
         }
         timer_mod(cpu->gt_timer[timeridx], nexttick);
+        trace_arm_gt_recalc(timeridx, irqstate, nexttick);
     } else {
         /* Timer disabled: ISTATUS and timer output always clear */
         gt->ctl &= ~4;
         qemu_set_irq(cpu->gt_timer_outputs[timeridx], 0);
         timer_del(cpu->gt_timer[timeridx]);
+        trace_arm_gt_recalc_disabled(timeridx);
     }
 }
 
@@ -1610,6 +1616,7 @@ static void gt_cval_write(CPUARMState *env, const ARMCPRegInfo *ri,
                           int timeridx,
                           uint64_t value)
 {
+    trace_arm_gt_cval_write(timeridx, value);
     env->cp15.c14_timer[timeridx].cval = value;
     gt_recalc_timer(arm_env_get_cpu(env), timeridx);
 }
@@ -1629,6 +1636,7 @@ static void gt_tval_write(CPUARMState *env, const ARMCPRegInfo *ri,
 {
     uint64_t offset = timeridx == GTIMER_VIRT ? env->cp15.cntvoff_el2 : 0;
 
+    trace_arm_gt_tval_write(timeridx, value);
     env->cp15.c14_timer[timeridx].cval = gt_get_countervalue(env) - offset +
                                          sextract64(value, 0, 32);
     gt_recalc_timer(arm_env_get_cpu(env), timeridx);
@@ -1641,6 +1649,7 @@ static void gt_ctl_write(CPUARMState *env, const ARMCPRegInfo *ri,
     ARMCPU *cpu = arm_env_get_cpu(env);
     uint32_t oldval = env->cp15.c14_timer[timeridx].ctl;
 
+    trace_arm_gt_ctl_write(timeridx, value);
     env->cp15.c14_timer[timeridx].ctl = deposit64(oldval, 0, 2, value);
     if ((oldval ^ value) & 1) {
         /* Enable toggled */
@@ -1649,8 +1658,10 @@ static void gt_ctl_write(CPUARMState *env, const ARMCPRegInfo *ri,
         /* IMASK toggled: don't need to recalculate,
          * just set the interrupt line based on ISTATUS
          */
-        qemu_set_irq(cpu->gt_timer_outputs[timeridx],
-                     (oldval & 4) && !(value & 2));
+        int irqstate = (oldval & 4) && !(value & 2);
+
+        trace_arm_gt_imask_toggle(timeridx, irqstate);
+        qemu_set_irq(cpu->gt_timer_outputs[timeridx], irqstate);
     }
 }
 
@@ -1715,6 +1726,7 @@ static void gt_cntvoff_write(CPUARMState *env, const ARMCPRegInfo *ri,
 {
     ARMCPU *cpu = arm_env_get_cpu(env);
 
+    trace_arm_gt_cntvoff_write(value);
     raw_write(env, ri, value);
     gt_recalc_timer(cpu, GTIMER_VIRT);
 }
diff --git a/target-arm/trace-events b/target-arm/trace-events
new file mode 100644
index 0000000..9f726bd
--- /dev/null
+++ b/target-arm/trace-events
@@ -0,0 +1,10 @@
+# See docs/tracing.txt for syntax documentation.
+
+# target-arm/helper.c
+arm_gt_recalc(int timer, int irqstate, uint64_t nexttick) "gt recalc: timer %d irqstate %d next tick %" PRIx64
+arm_gt_recalc_disabled(int timer) "gt recalc: timer %d irqstate 0 timer disabled"
+arm_gt_cval_write(int timer, uint64_t value) "gt_cval_write: timer %d value %" PRIx64
+arm_gt_tval_write(int timer, uint64_t value) "gt_tval_write: timer %d value %" PRIx64
+arm_gt_ctl_write(int timer, uint64_t value) "gt_ctl_write: timer %d value %" PRIx64
+arm_gt_imask_toggle(int timer, int irqstate) "gt_ctl_write: timer %d IMASK toggle, new irqstate %d"
+arm_gt_cntvoff_write(uint64_t value) "gt_cntvoff_write: value %" PRIx64