clock: Add ClockEvent parameter to callbacks

The Clock framework allows users to specify a callback which is
called after the clock's period has been updated.  Some users need to
also have a callback which is called before the clock period is
updated.

As the first step in adding support for notifying Clock users on
pre-update events, add an argument to the ClockCallback to specify
what event is being notified, and add an argument to the various
functions for registering a callback to specify which events are
of interest to that callback.

Note that the documentation update renders correct the previously
incorrect claim in 'Adding a new clock' that callbacks "will be
explained in a following section".

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Luc Michel <luc@lmichel.fr>
Tested-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210219144617.4782-2-peter.maydell@linaro.org

1 files changed, 3 insertions, 2 deletions

diff --git a/hw/timer/cmsdk-apb-dualtimer.c b/hw/timer/cmsdk-apb-dualtimer.c
index ef49f5852d..d4a509c798 100644
--- a/hw/timer/cmsdk-apb-dualtimer.c
+++ b/hw/timer/cmsdk-apb-dualtimer.c
@@ -449,7 +449,7 @@ static void cmsdk_apb_dualtimer_reset(DeviceState *dev)
     s->timeritop = 0;
 }
 
-static void cmsdk_apb_dualtimer_clk_update(void *opaque)
+static void cmsdk_apb_dualtimer_clk_update(void *opaque, ClockEvent event)
 {
     CMSDKAPBDualTimer *s = CMSDK_APB_DUALTIMER(opaque);
     int i;
@@ -478,7 +478,8 @@ static void cmsdk_apb_dualtimer_init(Object *obj)
         sysbus_init_irq(sbd, &s->timermod[i].timerint);
     }
     s->timclk = qdev_init_clock_in(DEVICE(s), "TIMCLK",
-                                   cmsdk_apb_dualtimer_clk_update, s);
+                                   cmsdk_apb_dualtimer_clk_update, s,
+                                   ClockUpdate);
 }
 
 static void cmsdk_apb_dualtimer_realize(DeviceState *dev, Error **errp)