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-rw-r--r--target/arm/cpu.c31
1 files changed, 17 insertions, 14 deletions
diff --git a/target/arm/cpu.c b/target/arm/cpu.c
index a152def241..9f2ca6633a 100644
--- a/target/arm/cpu.c
+++ b/target/arm/cpu.c
@@ -1506,9 +1506,12 @@ static void arm_cpu_initfn(Object *obj)
     }
 }
 
+/*
+ * 0 means "unset, use the default value". That default might vary depending
+ * on the CPU type, and is set in the realize fn.
+ */
 static Property arm_cpu_gt_cntfrq_property =
-            DEFINE_PROP_UINT64("cntfrq", ARMCPU, gt_cntfrq_hz,
-                               NANOSECONDS_PER_SECOND / GTIMER_SCALE);
+            DEFINE_PROP_UINT64("cntfrq", ARMCPU, gt_cntfrq_hz, 0);
 
 static Property arm_cpu_reset_cbar_property =
             DEFINE_PROP_UINT64("reset-cbar", ARMCPU, reset_cbar, 0);
@@ -1954,6 +1957,17 @@ static void arm_cpu_realizefn(DeviceState *dev, Error **errp)
         return;
     }
 
+    if (!cpu->gt_cntfrq_hz) {
+        /*
+         * 0 means "the board didn't set a value, use the default".
+         * The default value of the generic timer frequency (as seen in
+         * CNTFRQ_EL0) is 62.5MHz, which corresponds to a period of 16ns.
+         * This is what you get (a) for a CONFIG_USER_ONLY CPU (b) if the
+         * board doesn't set it.
+         */
+        cpu->gt_cntfrq_hz = GTIMER_DEFAULT_HZ;
+    }
+
 #ifndef CONFIG_USER_ONLY
     /* The NVIC and M-profile CPU are two halves of a single piece of
      * hardware; trying to use one without the other is a command line
@@ -2002,18 +2016,7 @@ static void arm_cpu_realizefn(DeviceState *dev, Error **errp)
     }
 
     {
-        uint64_t scale;
-
-        if (arm_feature(env, ARM_FEATURE_GENERIC_TIMER)) {
-            if (!cpu->gt_cntfrq_hz) {
-                error_setg(errp, "Invalid CNTFRQ: %"PRId64"Hz",
-                           cpu->gt_cntfrq_hz);
-                return;
-            }
-            scale = gt_cntfrq_period_ns(cpu);
-        } else {
-            scale = GTIMER_SCALE;
-        }
+        uint64_t scale = gt_cntfrq_period_ns(cpu);
 
         cpu->gt_timer[GTIMER_PHYS] = timer_new(QEMU_CLOCK_VIRTUAL, scale,
                                                arm_gt_ptimer_cb, cpu);