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, 5 insertions, 3 deletions

diff --git a/hw/core/qdev-clock.c b/hw/core/qdev-clock.c
index eb05f2a..117f4c6 100644
--- a/hw/core/qdev-clock.c
+++ b/hw/core/qdev-clock.c
@@ -111,7 +111,8 @@ Clock *qdev_init_clock_out(DeviceState *dev, const char *name)
 }
 
 Clock *qdev_init_clock_in(DeviceState *dev, const char *name,
-                            ClockCallback *callback, void *opaque)
+                          ClockCallback *callback, void *opaque,
+                          unsigned int events)
 {
     NamedClockList *ncl;
 
@@ -120,7 +121,7 @@ Clock *qdev_init_clock_in(DeviceState *dev, const char *name,
     ncl = qdev_init_clocklist(dev, name, false, NULL);
 
     if (callback) {
-        clock_set_callback(ncl->clock, callback, opaque);
+        clock_set_callback(ncl->clock, callback, opaque, events);
     }
     return ncl->clock;
 }
@@ -137,7 +138,8 @@ void qdev_init_clocks(DeviceState *dev, const ClockPortInitArray clocks)
         if (elem->is_output) {
             *clkp = qdev_init_clock_out(dev, elem->name);
         } else {
-            *clkp = qdev_init_clock_in(dev, elem->name, elem->callback, dev);
+            *clkp = qdev_init_clock_in(dev, elem->name, elem->callback, dev,
+                                       elem->callback_events);
         }
     }
 }