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From: Tony Lindgren <tony@atomide.com>
To: Grygorii Strashko <grygorii.strashko@ti.com>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>,
	Thomas Gleixner <tglx@linutronix.de>, Keerthy <j-keerthy@ti.com>,
	linux-kernel@vger.kernel.org, linux-omap@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 1/3] clocksource/drivers/timer-ti-dm: Fix posted mode status check order
Date: Fri, 5 Mar 2021 09:53:35 +0200	[thread overview]
Message-ID: <YEHjf6dcTByVvwBX@atomide.com> (raw)
In-Reply-To: <bd551701-da42-8f9f-ad49-5d87baa9beec@ti.com>

* Grygorii Strashko <grygorii.strashko@ti.com> [210304 20:58]:
> On 04/03/2021 09:21, Tony Lindgren wrote:
> > When the timer is configured in posted mode, we need to check the write-
> > posted status register (TWPS) before writing to the register.
...

> > --- a/drivers/clocksource/timer-ti-dm-systimer.c
> > +++ b/drivers/clocksource/timer-ti-dm-systimer.c
> > @@ -449,13 +449,13 @@ static int dmtimer_set_next_event(unsigned long cycles,
> >   	struct dmtimer_systimer *t = &clkevt->t;
> >   	void __iomem *pend = t->base + t->pend;
> > -	writel_relaxed(0xffffffff - cycles, t->base + t->counter);
> >   	while (readl_relaxed(pend) & WP_TCRR)
> >   		cpu_relax();
> > +	writel_relaxed(0xffffffff - cycles, t->base + t->counter);
> > -	writel_relaxed(OMAP_TIMER_CTRL_ST, t->base + t->ctrl);
> >   	while (readl_relaxed(pend) & WP_TCLR)
> >   		cpu_relax();
> > +	writel_relaxed(OMAP_TIMER_CTRL_ST, t->base + t->ctrl);
> 
> It seems static [and inline] helper here could be better solution. no?

Well we wanted to get rid of the confusing macros. And in this case I
suspect we can eventually do just one read of the pending register for
the registers used mask rather than check the status separately multiple
times. But that needs to be carefully tested and is not a fix :)

Regards,

Tony

WARNING: multiple messages have this Message-ID (diff)
From: Tony Lindgren <tony@atomide.com>
To: Grygorii Strashko <grygorii.strashko@ti.com>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>,
	Thomas Gleixner <tglx@linutronix.de>, Keerthy <j-keerthy@ti.com>,
	linux-kernel@vger.kernel.org, linux-omap@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 1/3] clocksource/drivers/timer-ti-dm: Fix posted mode status check order
Date: Fri, 5 Mar 2021 09:53:35 +0200	[thread overview]
Message-ID: <YEHjf6dcTByVvwBX@atomide.com> (raw)
In-Reply-To: <bd551701-da42-8f9f-ad49-5d87baa9beec@ti.com>

* Grygorii Strashko <grygorii.strashko@ti.com> [210304 20:58]:
> On 04/03/2021 09:21, Tony Lindgren wrote:
> > When the timer is configured in posted mode, we need to check the write-
> > posted status register (TWPS) before writing to the register.
...

> > --- a/drivers/clocksource/timer-ti-dm-systimer.c
> > +++ b/drivers/clocksource/timer-ti-dm-systimer.c
> > @@ -449,13 +449,13 @@ static int dmtimer_set_next_event(unsigned long cycles,
> >   	struct dmtimer_systimer *t = &clkevt->t;
> >   	void __iomem *pend = t->base + t->pend;
> > -	writel_relaxed(0xffffffff - cycles, t->base + t->counter);
> >   	while (readl_relaxed(pend) & WP_TCRR)
> >   		cpu_relax();
> > +	writel_relaxed(0xffffffff - cycles, t->base + t->counter);
> > -	writel_relaxed(OMAP_TIMER_CTRL_ST, t->base + t->ctrl);
> >   	while (readl_relaxed(pend) & WP_TCLR)
> >   		cpu_relax();
> > +	writel_relaxed(OMAP_TIMER_CTRL_ST, t->base + t->ctrl);
> 
> It seems static [and inline] helper here could be better solution. no?

Well we wanted to get rid of the confusing macros. And in this case I
suspect we can eventually do just one read of the pending register for
the registers used mask rather than check the status separately multiple
times. But that needs to be carefully tested and is not a fix :)

Regards,

Tony

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linux-arm-kernel@lists.infradead.org
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  reply	other threads:[~2021-03-05  7:53 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-04  7:21 [PATCH 0/3] Fixes for timer-ti-dm systimer posted mode Tony Lindgren
2021-03-04  7:21 ` Tony Lindgren
2021-03-04  7:21 ` [PATCH 1/3] clocksource/drivers/timer-ti-dm: Fix posted mode status check order Tony Lindgren
2021-03-04  7:21   ` Tony Lindgren
2021-03-04 20:57   ` Grygorii Strashko
2021-03-04 20:57     ` Grygorii Strashko
2021-03-05  7:53     ` Tony Lindgren [this message]
2021-03-05  7:53       ` Tony Lindgren
2021-03-05 10:09       ` Grygorii Strashko
2021-03-05 10:09         ` Grygorii Strashko
2021-04-09 10:27   ` [tip: timers/core] " tip-bot2 for Tony Lindgren
2021-03-04  7:21 ` [PATCH 2/3] clocksource/drivers/timer-ti-dm: Remove extra of_node_put() Tony Lindgren
2021-03-04  7:21   ` Tony Lindgren
2021-03-04 20:55   ` Grygorii Strashko
2021-03-04 20:55     ` Grygorii Strashko
2021-03-05  7:49     ` Tony Lindgren
2021-03-05  7:49       ` Tony Lindgren
2021-03-08 15:26       ` Tony Lindgren
2021-03-08 15:26         ` Tony Lindgren
2021-03-20 22:13         ` Daniel Lezcano
2021-03-20 22:13           ` Daniel Lezcano
2021-03-04  7:21 ` [PATCH 3/3] clocksource/drivers/timer-ti-dm: Add missing set_state_oneshot_stopped Tony Lindgren
2021-03-04  7:21   ` Tony Lindgren
2021-04-09 10:27   ` [tip: timers/core] " tip-bot2 for Tony Lindgren

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