hw/timer: Refactor NPCM7XX Timer to use CLK clock

This patch makes NPCM7XX Timer to use a the timer clock generated by the
CLK module instead of the magic number TIMER_REF_HZ.

Reviewed-by: Havard Skinnemoen <hskinnemoen@google.com>
Reviewed-by: Tyrone Ting <kfting@nuvoton.com>
Signed-off-by: Hao Wu <wuhaotsh@google.com>
Message-id: 20210108190945.949196-3-wuhaotsh@google.com
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

hw/arm/npcm7xx.c

@@ -22,6 +22,7 @@
 #include "hw/char/serial.h"
 #include "hw/loader.h"
 #include "hw/misc/unimp.h"
+#include "hw/qdev-clock.h"
 #include "hw/qdev-properties.h"
 #include "qapi/error.h"
 #include "qemu/units.h"
@@ -420,6 +421,10 @@ static void npcm7xx_realize(DeviceState *dev, Error **errp)
         int first_irq;
         int j;
 
+        /* Connect the timer clock. */
+        qdev_connect_clock_in(DEVICE(&s->tim[i]), "clock", qdev_get_clock_out(
+                    DEVICE(&s->clk), "timer-clock"));
+
         sysbus_realize(sbd, &error_abort);
         sysbus_mmio_map(sbd, 0, npcm7xx_tim_addr[i]);
 

hw/timer/npcm7xx_timer.c

@@ -17,8 +17,8 @@
 #include "qemu/osdep.h"
 
 #include "hw/irq.h"
+#include "hw/qdev-clock.h"
 #include "hw/qdev-properties.h"
-#include "hw/misc/npcm7xx_clk.h"
 #include "hw/timer/npcm7xx_timer.h"
 #include "migration/vmstate.h"
 #include "qemu/bitops.h"
@@ -128,23 +128,18 @@ static uint32_t npcm7xx_tcsr_prescaler(uint32_t tcsr)
 /* Convert a timer cycle count to a time interval in nanoseconds. */
 static int64_t npcm7xx_timer_count_to_ns(NPCM7xxTimer *t, uint32_t count)
 {
-    int64_t ns = count;
+    int64_t ticks = count;
 
-    ns *= NANOSECONDS_PER_SECOND / NPCM7XX_TIMER_REF_HZ;
+    ticks *= npcm7xx_tcsr_prescaler(t->tcsr);
-    ns *= npcm7xx_tcsr_prescaler(t->tcsr);
 
-    return ns;
+    return clock_ticks_to_ns(t->ctrl->clock, ticks);
 }
 
 /* Convert a time interval in nanoseconds to a timer cycle count. */
 static uint32_t npcm7xx_timer_ns_to_count(NPCM7xxTimer *t, int64_t ns)
 {
-    int64_t count;
+    return ns / clock_ticks_to_ns(t->ctrl->clock,
-
+                                  npcm7xx_tcsr_prescaler(t->tcsr));
-    count = ns / (NANOSECONDS_PER_SECOND / NPCM7XX_TIMER_REF_HZ);
-    count /= npcm7xx_tcsr_prescaler(t->tcsr);
-
-    return count;
 }
 
 static uint32_t npcm7xx_watchdog_timer_prescaler(const NPCM7xxWatchdogTimer *t)
@@ -166,8 +161,8 @@ static uint32_t npcm7xx_watchdog_timer_prescaler(const NPCM7xxWatchdogTimer *t)
 static void npcm7xx_watchdog_timer_reset_cycles(NPCM7xxWatchdogTimer *t,
         int64_t cycles)
 {
-    uint32_t prescaler = npcm7xx_watchdog_timer_prescaler(t);
+    int64_t ticks = cycles * npcm7xx_watchdog_timer_prescaler(t);
-    int64_t ns = (NANOSECONDS_PER_SECOND / NPCM7XX_TIMER_REF_HZ) * cycles;
+    int64_t ns = clock_ticks_to_ns(t->ctrl->clock, ticks);
 
     /*
      * The reset function always clears the current timer. The caller of the
@@ -176,7 +171,6 @@ static void npcm7xx_watchdog_timer_reset_cycles(NPCM7xxWatchdogTimer *t,
      */
     npcm7xx_timer_clear(&t->base_timer);
 
-    ns *= prescaler;
     t->base_timer.remaining_ns = ns;
 }
 
@@ -606,10 +600,11 @@ static void npcm7xx_timer_hold_reset(Object *obj)
     qemu_irq_lower(s->watchdog_timer.irq);
 }
 
-static void npcm7xx_timer_realize(DeviceState *dev, Error **errp)
+static void npcm7xx_timer_init(Object *obj)
 {
-    NPCM7xxTimerCtrlState *s = NPCM7XX_TIMER(dev);
+    NPCM7xxTimerCtrlState *s = NPCM7XX_TIMER(obj);
-    SysBusDevice *sbd = &s->parent;
+    DeviceState *dev = DEVICE(obj);
+    SysBusDevice *sbd = SYS_BUS_DEVICE(obj);
     int i;
     NPCM7xxWatchdogTimer *w;
 
@@ -627,11 +622,12 @@ static void npcm7xx_timer_realize(DeviceState *dev, Error **errp)
             npcm7xx_watchdog_timer_expired, w);
     sysbus_init_irq(sbd, &w->irq);
 
-    memory_region_init_io(&s->iomem, OBJECT(s), &npcm7xx_timer_ops, s,
+    memory_region_init_io(&s->iomem, obj, &npcm7xx_timer_ops, s,
                           TYPE_NPCM7XX_TIMER, 4 * KiB);
     sysbus_init_mmio(sbd, &s->iomem);
     qdev_init_gpio_out_named(dev, &w->reset_signal,
             NPCM7XX_WATCHDOG_RESET_GPIO_OUT, 1);
+    s->clock = qdev_init_clock_in(dev, "clock", NULL, NULL);
 }
 
 static const VMStateDescription vmstate_npcm7xx_base_timer = {
@@ -675,10 +671,11 @@ static const VMStateDescription vmstate_npcm7xx_watchdog_timer = {
 
 static const VMStateDescription vmstate_npcm7xx_timer_ctrl = {
     .name = "npcm7xx-timer-ctrl",
-    .version_id = 1,
+    .version_id = 2,
-    .minimum_version_id = 1,
+    .minimum_version_id = 2,
     .fields = (VMStateField[]) {
         VMSTATE_UINT32(tisr, NPCM7xxTimerCtrlState),
+        VMSTATE_CLOCK(clock, NPCM7xxTimerCtrlState),
         VMSTATE_STRUCT_ARRAY(timer, NPCM7xxTimerCtrlState,
                              NPCM7XX_TIMERS_PER_CTRL, 0, vmstate_npcm7xx_timer,
                              NPCM7xxTimer),
@@ -697,7 +694,6 @@ static void npcm7xx_timer_class_init(ObjectClass *klass, void *data)
     QEMU_BUILD_BUG_ON(NPCM7XX_TIMER_REGS_END > NPCM7XX_TIMER_NR_REGS);
 
     dc->desc = "NPCM7xx Timer Controller";
-    dc->realize = npcm7xx_timer_realize;
     dc->vmsd = &vmstate_npcm7xx_timer_ctrl;
     rc->phases.enter = npcm7xx_timer_enter_reset;
     rc->phases.hold = npcm7xx_timer_hold_reset;
@@ -708,6 +704,7 @@ static const TypeInfo npcm7xx_timer_info = {
     .parent             = TYPE_SYS_BUS_DEVICE,
     .instance_size      = sizeof(NPCM7xxTimerCtrlState),
     .class_init         = npcm7xx_timer_class_init,
+    .instance_init      = npcm7xx_timer_init,
 };
 
 static void npcm7xx_timer_register_type(void)

include/hw/misc/npcm7xx_clk.h

@@ -20,12 +20,6 @@
 #include "hw/clock.h"
 #include "hw/sysbus.h"
 
-/*
- * The reference clock frequency for the timer modules, and the SECCNT and
- * CNTR25M registers in this module, is always 25 MHz.
- */
-#define NPCM7XX_TIMER_REF_HZ            (25000000)
-
 /*
  * Number of registers in our device state structure. Don't change this without
  * incrementing the version_id in the vmstate.

include/hw/timer/npcm7xx_timer.h

@@ -101,6 +101,7 @@ struct NPCM7xxTimerCtrlState {
 
     uint32_t    tisr;
 
+    Clock       *clock;
     NPCM7xxTimer timer[NPCM7XX_TIMERS_PER_CTRL];
     NPCM7xxWatchdogTimer watchdog_timer;
 };