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/char/pl011.c b/hw/char/pl011.c
index ea4a4e5235..c5621a195f 100644
--- a/hw/char/pl011.c
+++ b/hw/char/pl011.c
@@ -309,7 +309,7 @@ static void pl011_event(void *opaque, QEMUChrEvent event)
         pl011_put_fifo(opaque, 0x400);
 }
 
-static void pl011_clock_update(void *opaque)
+static void pl011_clock_update(void *opaque, ClockEvent event)
 {
     PL011State *s = PL011(opaque);
 
@@ -378,7 +378,8 @@ static void pl011_init(Object *obj)
         sysbus_init_irq(sbd, &s->irq[i]);
     }
 
-    s->clk = qdev_init_clock_in(DEVICE(obj), "clk", pl011_clock_update, s);
+    s->clk = qdev_init_clock_in(DEVICE(obj), "clk", pl011_clock_update, s,
+                                ClockUpdate);
 
     s->read_trigger = 1;
     s->ifl = 0x12;