| Message ID | 20240325152827.73817-2-philmd@linaro.org |
|---|---|
| State | Superseded |
| Headers | show |
| Series | hw/clock: Propagate clock changes when STM32L4X5 MUX is updated | expand |
On Tue, Mar 26, 2024 at 1:29 AM Philippe Mathieu-Daudé <philmd@linaro.org> wrote: > > Let clock_set_mul_div() return a boolean value whether the > clock has been updated or not, similarly to clock_set(). > > Return early when clock_set_mul_div() is called with > same mul/div values the clock has. > > Acked-by: Luc Michel <luc@lmichel.fr> > Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org> Reviewed-by: Alistair Francis <alistair.francis@wdc.com> Alistair > --- > docs/devel/clocks.rst | 4 ++++ > include/hw/clock.h | 4 +++- > hw/core/clock.c | 8 +++++++- > 3 files changed, 14 insertions(+), 2 deletions(-) > > diff --git a/docs/devel/clocks.rst b/docs/devel/clocks.rst > index c4d14bde04..b2d1148cdb 100644 > --- a/docs/devel/clocks.rst > +++ b/docs/devel/clocks.rst > @@ -279,6 +279,10 @@ You can change the multiplier and divider of a clock at runtime, > so you can use this to model clock controller devices which > have guest-programmable frequency multipliers or dividers. > > +Similary to ``clock_set()``, ``clock_set_mul_div()`` returns ``true`` if > +the clock state was modified; that is, if the multiplier or the diviser > +or both were changed by the call. > + > Note that ``clock_set_mul_div()`` does not automatically call > ``clock_propagate()``. If you make a runtime change to the > multiplier or divider you must call clock_propagate() yourself. > diff --git a/include/hw/clock.h b/include/hw/clock.h > index bb12117f67..eb58599131 100644 > --- a/include/hw/clock.h > +++ b/include/hw/clock.h > @@ -357,6 +357,8 @@ char *clock_display_freq(Clock *clk); > * @multiplier: multiplier value > * @divider: divider value > * > + * @return: true if the clock is changed. > + * > * By default, a Clock's children will all run with the same period > * as their parent. This function allows you to adjust the multiplier > * and divider used to derive the child clock frequency. > @@ -374,6 +376,6 @@ char *clock_display_freq(Clock *clk); > * Note that this function does not call clock_propagate(); the > * caller should do that if necessary. > */ > -void clock_set_mul_div(Clock *clk, uint32_t multiplier, uint32_t divider); > +bool clock_set_mul_div(Clock *clk, uint32_t multiplier, uint32_t divider); > > #endif /* QEMU_HW_CLOCK_H */ > diff --git a/hw/core/clock.c b/hw/core/clock.c > index d82e44cd1a..a19c7db7df 100644 > --- a/hw/core/clock.c > +++ b/hw/core/clock.c > @@ -143,14 +143,20 @@ char *clock_display_freq(Clock *clk) > return freq_to_str(clock_get_hz(clk)); > } > > -void clock_set_mul_div(Clock *clk, uint32_t multiplier, uint32_t divider) > +bool clock_set_mul_div(Clock *clk, uint32_t multiplier, uint32_t divider) > { > assert(divider != 0); > > + if (clk->multiplier == multiplier && clk->divider == divider) { > + return false; > + } > + > trace_clock_set_mul_div(CLOCK_PATH(clk), clk->multiplier, multiplier, > clk->divider, divider); > clk->multiplier = multiplier; > clk->divider = divider; > + > + return true; > } > > static void clock_initfn(Object *obj) > -- > 2.41.0 > >
diff --git a/docs/devel/clocks.rst b/docs/devel/clocks.rst index c4d14bde04..b2d1148cdb 100644 --- a/docs/devel/clocks.rst +++ b/docs/devel/clocks.rst @@ -279,6 +279,10 @@ You can change the multiplier and divider of a clock at runtime, so you can use this to model clock controller devices which have guest-programmable frequency multipliers or dividers. +Similary to ``clock_set()``, ``clock_set_mul_div()`` returns ``true`` if +the clock state was modified; that is, if the multiplier or the diviser +or both were changed by the call. + Note that ``clock_set_mul_div()`` does not automatically call ``clock_propagate()``. If you make a runtime change to the multiplier or divider you must call clock_propagate() yourself. diff --git a/include/hw/clock.h b/include/hw/clock.h index bb12117f67..eb58599131 100644 --- a/include/hw/clock.h +++ b/include/hw/clock.h @@ -357,6 +357,8 @@ char *clock_display_freq(Clock *clk); * @multiplier: multiplier value * @divider: divider value * + * @return: true if the clock is changed. + * * By default, a Clock's children will all run with the same period * as their parent. This function allows you to adjust the multiplier * and divider used to derive the child clock frequency. @@ -374,6 +376,6 @@ char *clock_display_freq(Clock *clk); * Note that this function does not call clock_propagate(); the * caller should do that if necessary. */ -void clock_set_mul_div(Clock *clk, uint32_t multiplier, uint32_t divider); +bool clock_set_mul_div(Clock *clk, uint32_t multiplier, uint32_t divider); #endif /* QEMU_HW_CLOCK_H */ diff --git a/hw/core/clock.c b/hw/core/clock.c index d82e44cd1a..a19c7db7df 100644 --- a/hw/core/clock.c +++ b/hw/core/clock.c @@ -143,14 +143,20 @@ char *clock_display_freq(Clock *clk) return freq_to_str(clock_get_hz(clk)); } -void clock_set_mul_div(Clock *clk, uint32_t multiplier, uint32_t divider) +bool clock_set_mul_div(Clock *clk, uint32_t multiplier, uint32_t divider) { assert(divider != 0); + if (clk->multiplier == multiplier && clk->divider == divider) { + return false; + } + trace_clock_set_mul_div(CLOCK_PATH(clk), clk->multiplier, multiplier, clk->divider, divider); clk->multiplier = multiplier; clk->divider = divider; + + return true; } static void clock_initfn(Object *obj)