hw/timer/cmsdk-apb-dualtimer: Convert to use Clock input

Switch the CMSDK APB dualtimer device over to using its Clock input;
the pclk-frq property is now ignored.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Luc Michel <luc@lmichel.fr>
Tested-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-id: 20210128114145.20536-20-peter.maydell@linaro.org
Message-id: 20210121190622.22000-20-peter.maydell@linaro.org
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>

hw/timer/cmsdk-apb-dualtimer.c

@@ -106,6 +106,22 @@ static void cmsdk_apb_dualtimer_update(CMSDKAPBDualTimer *s)
     qemu_set_irq(s->timerintc, timintc);
 }
 
+static int cmsdk_dualtimermod_divisor(CMSDKAPBDualTimerModule *m)
+{
+    /* Return the divisor set by the current CONTROL.PRESCALE value */
+    switch (FIELD_EX32(m->control, CONTROL, PRESCALE)) {
+    case 0:
+        return 1;
+    case 1:
+        return 16;
+    case 2:
+    case 3: /* UNDEFINED, we treat like 2 (and complained when it was set) */
+        return 256;
+    default:
+        g_assert_not_reached();
+    }
+}
+
 static void cmsdk_dualtimermod_write_control(CMSDKAPBDualTimerModule *m,
                                              uint32_t newctrl)
 {
@@ -146,7 +162,7 @@ static void cmsdk_dualtimermod_write_control(CMSDKAPBDualTimerModule *m,
         default:
             g_assert_not_reached();
         }
-        ptimer_set_freq(m->timer, m->parent->pclk_frq / divisor);
+        ptimer_set_period_from_clock(m->timer, m->parent->timclk, divisor);
     }
 
     if (changed & R_CONTROL_MODE_MASK) {
@@ -414,7 +430,8 @@ static void cmsdk_dualtimermod_reset(CMSDKAPBDualTimerModule *m)
      * limit must both be set to 0xffff, so we wrap at 16 bits.
      */
     ptimer_set_limit(m->timer, 0xffff, 1);
-    ptimer_set_freq(m->timer, m->parent->pclk_frq);
+    ptimer_set_period_from_clock(m->timer, m->parent->timclk,
+                                 cmsdk_dualtimermod_divisor(m));
     ptimer_transaction_commit(m->timer);
 }
 
@@ -432,6 +449,20 @@ static void cmsdk_apb_dualtimer_reset(DeviceState *dev)
     s->timeritop = 0;
 }
 
+static void cmsdk_apb_dualtimer_clk_update(void *opaque)
+{
+    CMSDKAPBDualTimer *s = CMSDK_APB_DUALTIMER(opaque);
+    int i;
+
+    for (i = 0; i < ARRAY_SIZE(s->timermod); i++) {
+        CMSDKAPBDualTimerModule *m = &s->timermod[i];
+        ptimer_transaction_begin(m->timer);
+        ptimer_set_period_from_clock(m->timer, m->parent->timclk,
+                                     cmsdk_dualtimermod_divisor(m));
+        ptimer_transaction_commit(m->timer);
+    }
+}
+
 static void cmsdk_apb_dualtimer_init(Object *obj)
 {
     SysBusDevice *sbd = SYS_BUS_DEVICE(obj);
@@ -446,16 +477,17 @@ static void cmsdk_apb_dualtimer_init(Object *obj)
     for (i = 0; i < ARRAY_SIZE(s->timermod); i++) {
         sysbus_init_irq(sbd, &s->timermod[i].timerint);
     }
-    s->timclk = qdev_init_clock_in(DEVICE(s), "TIMCLK", NULL, NULL);
+    s->timclk = qdev_init_clock_in(DEVICE(s), "TIMCLK",
+                                   cmsdk_apb_dualtimer_clk_update, s);
 }
 
 static void cmsdk_apb_dualtimer_realize(DeviceState *dev, Error **errp)
 {
     CMSDKAPBDualTimer *s = CMSDK_APB_DUALTIMER(dev);
     int i;
 
-    if (s->pclk_frq == 0) {
-        error_setg(errp, "CMSDK APB timer: pclk-frq property must be set");
+    if (!clock_has_source(s->timclk)) {
+        error_setg(errp, "CMSDK APB dualtimer: TIMCLK clock must be connected");
         return;
     }