From: David Lechner <david@lechnology.com>
To: Bartosz Golaszewski <brgl@bgdev.pl>
Cc: Sekhar Nori <nsekhar@ti.com>,
Daniel Lezcano <daniel.lezcano@linaro.org>,
Thomas Gleixner <tglx@linutronix.de>,
Kevin Hilman <khilman@kernel.org>,
Linux ARM <linux-arm-kernel@lists.infradead.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Bartosz Golaszewski <bgolaszewski@baylibre.com>
Subject: Re: [PATCH 1/3] clocksource: davinci: work around a clocksource problem on dm365 SoC
Date: Tue, 17 Dec 2019 11:01:28 -0600 [thread overview]
Message-ID: <a68ca8a5-77c6-4aac-f3b6-67edbf42a9bf@lechnology.com> (raw)
In-Reply-To: <CAMRc=McRKwYkUcY9J8cEkwoMnGYxs7SkTnOnFsVMDZD2DkJ1Zw@mail.gmail.com>
On 12/17/19 2:00 AM, Bartosz Golaszewski wrote:
> pon., 16 gru 2019 o 18:58 David Lechner <david@lechnology.com> napisał(a):
>>
>>>
>>> +static unsigned int davinci_clocksource_tim32_mode;
>>
>> static unsigned bool davinci_clocksource_initialized;
>>
>>> +
>>> static struct davinci_clockevent *
>>> to_davinci_clockevent(struct clock_event_device *clockevent)
>>> {
>>> @@ -94,7 +96,7 @@ static void davinci_tim12_shutdown(void __iomem *base)
>>> * halves. In this case TIM34 runs in periodic mode and we must
>>> * not modify it.
>>> */
>>> - tcr |= DAVINCI_TIMER_ENAMODE_PERIODIC <<
>>> + tcr |= davinci_clocksource_tim32_mode <<
>>> DAVINCI_TIMER_ENAMODE_SHIFT_TIM34;
>>
>> if (davinci_clocksource_initialized)
>> tcr |= DAVINCI_TIMER_ENAMODE_PERIODIC <<
>> DAVINCI_TIMER_ENAMODE_SHIFT_TIM34;
>
> I thought about doing this initially, but then figured this code would
> be called a lot, so why not avoid branching and just store the right
> value? Alternatively we can do:
>
> if (likely(davinci_clocksource_initialized)
> ....
>
Unless there is a measurable performance difference, I think it
would be better with if/likely.
next prev parent reply other threads:[~2019-12-17 17:01 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-13 16:24 [PATCH 0/3] ARM: davinci: convert dm365 to using the new clocksource driver Bartosz Golaszewski
2019-12-13 16:24 ` [PATCH 1/3] clocksource: davinci: work around a clocksource problem on dm365 SoC Bartosz Golaszewski
2019-12-16 17:58 ` David Lechner
2019-12-17 8:00 ` Bartosz Golaszewski
2019-12-17 17:01 ` David Lechner [this message]
2019-12-18 9:28 ` Sekhar Nori
2019-12-19 8:59 ` Bartosz Golaszewski
2019-12-13 16:24 ` [PATCH 2/3] ARM: davinci: dm365: switch to using the clocksource driver Bartosz Golaszewski
2019-12-13 16:24 ` [PATCH 3/3] ARM: davinci: remove legacy timer support Bartosz Golaszewski
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