Messages in this thread Patch in this message | | | Subject | Re: [PATCH] clocksource/drivers/timer-mediatek: optimize systimer irq clear flow on Mediatek Socs | From | Daniel Lezcano <> | Date | Mon, 22 Mar 2021 11:10:50 +0100 |
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On 02/03/2021 08:28, Fengquan Chen wrote: > 1)ensure systimer is enabled before clear and disable interrupt, which only > for systimer in Mediatek Socs. > > 2)clear any pending timer-irq when shutdown to keep suspend flow clean, > when use systimer as tick-broadcast timer > > Change-Id: Ia3eda83324af2fdaf5cbb3569a9bf020a11f8009
Remove the above.
Add a Fixes tag.
> Signed-off-by: Fengquan Chen <fengquan.chen@mediatek.com> > --- > drivers/clocksource/timer-mediatek.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/drivers/clocksource/timer-mediatek.c b/drivers/clocksource/timer-mediatek.c > index 9318edc..9f1f095dc 100644 > --- a/drivers/clocksource/timer-mediatek.c > +++ b/drivers/clocksource/timer-mediatek.c > @@ -75,6 +75,7 @@ > static void mtk_syst_ack_irq(struct timer_of *to) > { > /* Clear and disable interrupt */ > + writel(SYST_CON_EN, SYST_CON_REG(to));
SYST_CON_EN is set below, why do you have to do it before?
Is that a hw bug ?
It is confusing what the description of the SYST_CON_EN says:
/* * SYST_CON_EN: Clock enable. Shall be set to * - Start timer countdown. * - Allow timeout ticks being updated. * - Allow changing interrupt functions.
What means "interrupt functions" ?
Does writing writel(SYST_CON_EN, SYST_CON_REG(to)) before SYST_CON_IRQ_CLR allows to clear the interrupt flag?
Can you explain how the timer works regarding this part?
It sounds to me a bit strange.
* * SYST_CON_IRQ_EN: Set to allow interrupt. * * SYST_CON_IRQ_CLR: Set to clear interrupt. */
> writel(SYST_CON_IRQ_CLR | SYST_CON_EN, SYST_CON_REG(to)); > } > > @@ -111,6 +112,9 @@ static int mtk_syst_clkevt_next_event(unsigned long ticks, > > static int mtk_syst_clkevt_shutdown(struct clock_event_device *clkevt) > { > + /* Clear any irq */ > + mtk_syst_ack_irq(to_timer_of(clkevt)); > + > /* Disable timer */ > writel(0, SYST_CON_REG(to_timer_of(clkevt))); > >
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