[Qemu-devel] [PATCH 5/7] allwinner-a10-pit: implement prescaler and source selection

[Beniamino Galvani]

This implements the prescaler and source fields of the timer control
register as described in the A10 user manual.

Signed-off-by: Beniamino Galvani <b.galv...@gmail.com>
---
 hw/timer/allwinner-a10-pit.c |   19 ++++++++++++++++++-
 1 file changed, 18 insertions(+), 1 deletion(-)

diff --git a/hw/timer/allwinner-a10-pit.c b/hw/timer/allwinner-a10-pit.c
index 4723b25..f2f2567 100644
--- a/hw/timer/allwinner-a10-pit.c
+++ b/hw/timer/allwinner-a10-pit.c
@@ -79,6 +79,23 @@ 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;
+    uint32_t source_freqs[] = {32768, 24000000};
+
+    prescaler = 1 << extract32(s->control[index], 4, 3);
+    source = extract32(s->control[index], 2, 2);
+
+    if (source > 1) {
+        qemu_log_mask(LOG_UNIMP, "%s: unimplemented clock source %d",
+                      __func__, source);
+        source = 0;
+    }
+
+    ptimer_set_freq(s->timer[index], source_freqs[source] / prescaler);
+}
+
 static void a10_pit_write(void *opaque, hwaddr offset, uint64_t value,
                             unsigned size)
 {
@@ -101,6 +118,7 @@ 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]);
             }
@@ -244,7 +262,6 @@ 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);
     }
 }
 
-- 
1.7.10.4