allwinner-a10-pit: implement prescaler and source selection

This implements the prescaler and source fields of the timer control
register. The source for each timer can be selected among 4 clock
inputs whose frequencies are set through model properties.

Signed-off-by: Beniamino Galvani <b.galvani@gmail.com>
Reviewed-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
Message-id: 1395771730-16882-6-git-send-email-b.galvani@gmail.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

hw/arm/cubieboard.c

@@ -43,6 +43,19 @@ static void cubieboard_init(QEMUMachineInitArgs *args)
         exit(1);
     }
 
+    object_property_set_int(OBJECT(&s->a10->timer), 32768, "clk0-freq", &err);
+    if (err != NULL) {
+        error_report("Couldn't set clk0 frequency: %s", error_get_pretty(err));
+        exit(1);
+    }
+
+    object_property_set_int(OBJECT(&s->a10->timer), 24000000, "clk1-freq",
+                            &err);
+    if (err != NULL) {
+        error_report("Couldn't set clk1 frequency: %s", error_get_pretty(err));
+        exit(1);
+    }
+
     object_property_set_bool(OBJECT(s->a10), true, "realized", &err);
     if (err != NULL) {
         error_report("Couldn't realize Allwinner A10: %s",

hw/timer/allwinner-a10-pit.c

@@ -74,6 +74,22 @@ static uint64_t a10_pit_read(void *opaque, hwaddr offset, unsigned size)
     return 0;
 }
 
+static void a10_pit_set_freq(AwA10PITState *s, int index)
+{
+    uint32_t prescaler, source, source_freq;
+
+    prescaler = 1 << extract32(s->control[index], 4, 3);
+    source = extract32(s->control[index], 2, 2);
+    source_freq = s->clk_freq[source];
+
+    if (source_freq) {
+        ptimer_set_freq(s->timer[index], source_freq / prescaler);
+    } else {
+        qemu_log_mask(LOG_GUEST_ERROR, "%s: Invalid clock source %u\n",
+                      __func__, source);
+    }
+}
+
 static void a10_pit_write(void *opaque, hwaddr offset, uint64_t value,
                             unsigned size)
 {
@@ -96,6 +112,7 @@ static void a10_pit_write(void *opaque, hwaddr offset, uint64_t value,
         switch (offset & 0x0f) {
         case AW_A10_PIT_TIMER_CONTROL:
             s->control[index] = value;
+            a10_pit_set_freq(s, index);
             if (s->control[index] & AW_A10_PIT_TIMER_RELOAD) {
                 ptimer_set_count(s->timer[index], s->interval[index]);
             }
@@ -161,6 +178,14 @@ static const MemoryRegionOps a10_pit_ops = {
     .endianness = DEVICE_NATIVE_ENDIAN,
 };
 
+static Property a10_pit_properties[] = {
+    DEFINE_PROP_UINT32("clk0-freq", AwA10PITState, clk_freq[0], 0),
+    DEFINE_PROP_UINT32("clk1-freq", AwA10PITState, clk_freq[1], 0),
+    DEFINE_PROP_UINT32("clk2-freq", AwA10PITState, clk_freq[2], 0),
+    DEFINE_PROP_UINT32("clk3-freq", AwA10PITState, clk_freq[3], 0),
+    DEFINE_PROP_END_OF_LIST(),
+};
+
 static const VMStateDescription vmstate_a10_pit = {
     .name = "a10.pit",
     .version_id = 1,
@@ -196,6 +221,7 @@ static void a10_pit_reset(DeviceState *dev)
         s->interval[i] = 0;
         s->count[i] = 0;
         ptimer_stop(s->timer[i]);
+        a10_pit_set_freq(s, i);
     }
     s->watch_dog_mode = 0;
     s->watch_dog_control = 0;
@@ -241,7 +267,6 @@ static void a10_pit_init(Object *obj)
         tc->index = i;
         bh[i] = qemu_bh_new(a10_pit_timer_cb, tc);
         s->timer[i] = ptimer_init(bh[i]);
-        ptimer_set_freq(s->timer[i], 240000);
     }
 }
 
@@ -250,6 +275,7 @@ static void a10_pit_class_init(ObjectClass *klass, void *data)
     DeviceClass *dc = DEVICE_CLASS(klass);
 
     dc->reset = a10_pit_reset;
+    dc->props = a10_pit_properties;
     dc->desc = "allwinner a10 timer";
     dc->vmsd = &vmstate_a10_pit;
 }

include/hw/timer/allwinner-a10-pit.h

@@ -50,6 +50,7 @@ struct AwA10PITState {
     ptimer_state * timer[AW_A10_PIT_TIMER_NR];
     AwA10TimerContext timer_context[AW_A10_PIT_TIMER_NR];
     MemoryRegion iomem;
+    uint32_t clk_freq[4];
 
     uint32_t irq_enable;
     uint32_t irq_status;