[Qemu-devel] [PATCH v3 5/7] allwinner-a10-pit: implement prescaler and source selection

[Beniamino Galvani <b.galvani@gmail.com>]

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.galvani@gmail.com>
---
 hw/timer/allwinner-a10-pit.c         |   30 +++++++++++++++++++++++++++++-
 include/hw/timer/allwinner-a10-pit.h |    8 ++++++++
 2 files changed, 37 insertions(+), 1 deletion(-)

diff --git a/hw/timer/allwinner-a10-pit.c b/hw/timer/allwinner-a10-pit.c
index f8c9236..a448689 100644
--- a/hw/timer/allwinner-a10-pit.c
+++ b/hw/timer/allwinner-a10-pit.c
@@ -74,6 +74,34 @@ 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_freq = AW_A10_PIT_OSC24M_FREQ;
+
+    prescaler = 1 << extract32(s->control[index], 4, 3);
+    source = extract32(s->control[index], 2, 2);
+
+    switch (source) {
+    case AW_A10_PIT_SOURCE_LS_OSC:
+        source_freq = AW_A10_PIT_LS_OSC_FREQ;
+        break;
+    case AW_A10_PIT_SOURCE_OSC24M:
+        source_freq = AW_A10_PIT_OSC24M_FREQ;
+        break;
+    case AW_A10_PIT_SOURCE_PLL6:
+        qemu_log_mask(LOG_UNIMP, "%s: unimplemented clock source %u", __func__,
+                      source);
+        break;
+    case AW_A10_PIT_SOURCE_UNDEF:
+        qemu_log_mask(LOG_GUEST_ERROR, "%s: invalid clock source %u", __func__,
+                      source);
+        break;
+    }
+
+    ptimer_set_freq(s->timer[index], source_freq / prescaler);
+}
+
 static void a10_pit_write(void *opaque, hwaddr offset, uint64_t value,
                             unsigned size)
 {
@@ -96,6 +124,7 @@ 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]);
             }
@@ -239,7 +268,6 @@ 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);
     }
 }
 
diff --git a/include/hw/timer/allwinner-a10-pit.h b/include/hw/timer/allwinner-a10-pit.h
index a48d3c7..37a2662 100644
--- a/include/hw/timer/allwinner-a10-pit.h
+++ b/include/hw/timer/allwinner-a10-pit.h
@@ -33,6 +33,14 @@
 #define AW_A10_PIT_TIMER_BASE_END  \
     (AW_A10_PIT_TIMER_BASE * 6 + AW_A10_PIT_TIMER_COUNT)
 
+#define AW_A10_PIT_SOURCE_LS_OSC   0
+#define AW_A10_PIT_SOURCE_OSC24M   1
+#define AW_A10_PIT_SOURCE_PLL6     2
+#define AW_A10_PIT_SOURCE_UNDEF    3
+
+#define AW_A10_PIT_LS_OSC_FREQ     32768
+#define AW_A10_PIT_OSC24M_FREQ     24000000
+
 #define AW_A10_PIT_DEFAULT_CLOCK   0x4
 
 typedef struct AwA10PITState AwA10PITState;
-- 
1.7.10.4