linux-kernel - Re: [PATCH v3 0/2] Allwinner A64 timer workaround

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Date:   Tue, 15 Jan 2019 10:52:08 +0800
From:   Chen-Yu Tsai <wens@...e.org>
To:     Daniel Lezcano <daniel.lezcano@...aro.org>
Cc:     Samuel Holland <samuel@...lland.org>,
        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will.deacon@....com>,
        Maxime Ripard <maxime.ripard@...tlin.com>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <Mark.Rutland@....com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Marc Zyngier <marc.zyngier@....com>,
        devicetree <devicetree@...r.kernel.org>,
        linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>,
        linux-kernel <linux-kernel@...r.kernel.org>,
        linux-sunxi <linux-sunxi@...glegroups.com>
Subject: Re: [PATCH v3 0/2] Allwinner A64 timer workaround

On Mon, Jan 14, 2019 at 8:57 PM Daniel Lezcano
<daniel.lezcano@...aro.org> wrote:
>
> On 13/01/2019 03:17, Samuel Holland wrote:
> > This is the third version of a patch series to fix system clock jumps
> > and other timer instability on the Allwinner A64 SoC. It has now been
> > tested for a week, and I've received no reports of date jumps with this
> > version. So this is, as far as I can tell, a complete workaround.
> >
> > See the commit messages for a detailed description of the issue, but the
> > summary is that, when a high counter bit rolls over, indeterminance in
> > the low bits causes CNTPCT/CNTVCT and their respective TVAL registers to
> > jump forward or backward. Backward jumps (or the next read after forward
> > jumps) are sometimes seen by the kernel and interpreted as the timer
> > wrapping around after 2^56 cycles. This causes the system clock to jump
> > forward approximately 91 years.
> >
> > changes since v2;
> > - Reduced workaround threshold from 11 to 10 bits based on reports from
> >   other hardare and the U-Boot version of this workaround
> > - Added TVAL handling based on Marc's suggestion
> > - Added erratum documentation and renamed symbols to match
> > - Added Maxime's Acked-by
> >
> > changes since v1:
> > - Add an iteration limit like most other arch timer workarounds
> > - Added Andre's Tested-by
> >
> > Samuel Holland (2):
> >   arm64: arch_timer: Workaround for Allwinner A64 timer instability
> >   arm64: dts: allwinner: a64: Enable A64 timer workaround
> >
> >  Documentation/arm64/silicon-errata.txt        |  2 +
> >  arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi |  1 +
> >  drivers/clocksource/Kconfig                   | 10 ++++
> >  drivers/clocksource/arm_arch_timer.c          | 55 +++++++++++++++++++
> >  4 files changed, 68 insertions(+)
> >
>
> Applied. Took the opportunity to add the stable@ tag.

Not seeing it in tip just yet. Was it applied for -rc or -next?
Need to know which branch to apply the device tree patch to.

Thanks
ChenYu