aspeed/timer: Add AST2600 support

The AST2600 timer has a third control register that is used to
implement a set-to-clear feature for the main control register.

On the AST2600, it is not configurable via 0x38 (control register 3)
as it is on the AST2500.

Based on previous work from Joel Stanley.

Signed-off-by: Cédric Le Goater <clg@kaod.org>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Message-id: 20190925143248.10000-7-clg@kaod.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

hw/timer/aspeed_timer.c

@@ -538,6 +538,40 @@ static void aspeed_2500_timer_write(AspeedTimerCtrlState *s, hwaddr offset,
     }
 }
 
+static uint64_t aspeed_2600_timer_read(AspeedTimerCtrlState *s, hwaddr offset)
+{
+    uint64_t value;
+
+    switch (offset) {
+    case 0x38:
+    case 0x3C:
+    default:
+        qemu_log_mask(LOG_GUEST_ERROR, "%s: Bad offset 0x%" HWADDR_PRIx "\n",
+                __func__, offset);
+        value = 0;
+        break;
+    }
+    return value;
+}
+
+static void aspeed_2600_timer_write(AspeedTimerCtrlState *s, hwaddr offset,
+                                    uint64_t value)
+{
+    const uint32_t tv = (uint32_t)(value & 0xFFFFFFFF);
+
+    switch (offset) {
+    case 0x3C:
+        aspeed_timer_set_ctrl(s, s->ctrl & ~tv);
+        break;
+
+    case 0x38:
+    default:
+        qemu_log_mask(LOG_GUEST_ERROR, "%s: Bad offset 0x%" HWADDR_PRIx "\n",
+                __func__, offset);
+        break;
+    }
+}
+
 static void aspeed_init_one_timer(AspeedTimerCtrlState *s, uint8_t id)
 {
     AspeedTimer *t = &s->timers[id];
@@ -674,11 +708,28 @@ static const TypeInfo aspeed_2500_timer_info = {
     .class_init = aspeed_2500_timer_class_init,
 };
 
+static void aspeed_2600_timer_class_init(ObjectClass *klass, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(klass);
+    AspeedTimerClass *awc = ASPEED_TIMER_CLASS(klass);
+
+    dc->desc = "ASPEED 2600 Timer";
+    awc->read = aspeed_2600_timer_read;
+    awc->write = aspeed_2600_timer_write;
+}
+
+static const TypeInfo aspeed_2600_timer_info = {
+    .name = TYPE_ASPEED_2600_TIMER,
+    .parent = TYPE_ASPEED_TIMER,
+    .class_init = aspeed_2600_timer_class_init,
+};
+
 static void aspeed_timer_register_types(void)
 {
     type_register_static(&aspeed_timer_info);
     type_register_static(&aspeed_2400_timer_info);
     type_register_static(&aspeed_2500_timer_info);
+    type_register_static(&aspeed_2600_timer_info);
 }
 
 type_init(aspeed_timer_register_types)

include/hw/timer/aspeed_timer.h

@@ -30,6 +30,7 @@
 #define TYPE_ASPEED_TIMER "aspeed.timer"
 #define TYPE_ASPEED_2400_TIMER TYPE_ASPEED_TIMER "-ast2400"
 #define TYPE_ASPEED_2500_TIMER TYPE_ASPEED_TIMER "-ast2500"
+#define TYPE_ASPEED_2600_TIMER TYPE_ASPEED_TIMER "-ast2600"
 
 #define ASPEED_TIMER_NR_TIMERS 8