From: Dmitry Osipenko <digetx@gmail.com>
To: Peter De Schrijver <pdeschrijver@nvidia.com>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>,
Thomas Gleixner <tglx@linutronix.de>,
Joseph Lo <josephl@nvidia.com>,
Thierry Reding <thierry.reding@gmail.com>,
Jonathan Hunter <jonathanh@nvidia.com>,
linux-tegra@vger.kernel.org, linux-kernel@vger.kernel.org,
Nicolas Chauvet <kwizart@gmail.com>
Subject: Re: [PATCH v3 0/8] NVIDIA Tegra clocksource driver improvements
Date: Fri, 31 May 2019 15:33:41 +0300 [thread overview]
Message-ID: <c686aae8-3be0-805e-265b-a7f16f2a6c02@gmail.com> (raw)
In-Reply-To: <20190531082634.GA6070@pdeschrijver-desktop.Nvidia.com>
31.05.2019 11:26, Peter De Schrijver пишет:
> On Fri, May 24, 2019 at 06:32:45PM +0300, Dmitry Osipenko wrote:
>> Hello,
>>
>> This series primarily unifies the driver code across all Tegra SoC
>> generations. In a result the clocksources are allocated per-CPU on
>> older Tegra's and have a higher rating than the arch-timer, the newer
>> Tegra210 is getting support for microsecond clocksource and the driver's
>> code is getting much cleaner. Note that arch-timer usage is discouraged on
>> all Tegra's due to the time jitter caused by the CPU frequency scaling.
>
> I think the limitations are more as follows:
>
> Chip timer suffers cpu dvfs jitter can wakeup from cc7
> T20 us-timer No Yes
> T20 twd timer Yes No?
> T30 us-timer No Yes
> T30 twd timer Yes No?
> T114 us-timer No Yes
> T114 arch timer No Yes
> T124 us-timer No Yes
> T124 arch timer No Yes
> T210 us-timer No Yes
> T210 arch timer No No
> T210 clk_m timer No Yes
>
> right?
Doesn't arch timer run off the CPU clock? If yes (that's what I
assumed), then it should be affected by the DVFS. Otherwise I'll lower
the clocksource's rating for T114/124/132.
TWD can't wake CPU from the power-down state, so it's a solid "No" for
TWD in the "can wakeup from cc7" column.
next prev parent reply other threads:[~2019-05-31 12:33 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-24 15:32 [PATCH v3 0/8] NVIDIA Tegra clocksource driver improvements Dmitry Osipenko
2019-05-24 15:32 ` [PATCH v3 1/8] clocksource/drivers/tegra: Support per-CPU timers on all Tegra's Dmitry Osipenko
2019-05-24 15:32 ` [PATCH v3 2/8] clocksource/drivers/tegra: Unify timer code Dmitry Osipenko
2019-05-24 15:32 ` [PATCH v3 3/8] clocksource/drivers/tegra: Reset hardware state on init Dmitry Osipenko
2019-05-24 15:32 ` [PATCH v3 4/8] clocksource/drivers/tegra: Replace readl/writel with relaxed versions Dmitry Osipenko
2019-05-24 15:32 ` [PATCH v3 5/8] clocksource/drivers/tegra: Release all IRQ's on request_irq() error Dmitry Osipenko
2019-05-24 15:32 ` [PATCH v3 6/8] clocksource/drivers/tegra: Minor code clean up Dmitry Osipenko
2019-05-24 15:32 ` [PATCH v3 7/8] clocksource/drivers/tegra: Use SPDX identifier Dmitry Osipenko
2019-05-24 15:32 ` [PATCH v3 8/8] clocksource/drivers/tegra: Support COMPILE_TEST universally Dmitry Osipenko
2019-05-31 8:26 ` [PATCH v3 0/8] NVIDIA Tegra clocksource driver improvements Peter De Schrijver
2019-05-31 8:26 ` Peter De Schrijver
2019-05-31 12:33 ` Dmitry Osipenko [this message]
2019-05-31 20:31 ` Daniel Lezcano
2019-06-01 13:00 ` Dmitry Osipenko
2019-06-03 7:17 ` Peter De Schrijver
2019-06-03 7:17 ` Peter De Schrijver
2019-06-03 11:14 ` Dmitry Osipenko
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