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Re: [PATCH 5/7] arm64: arch_timer: work around Hisilicon erratum 161010101

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On Tue, Jan 31, 2017 at 12:19:54PM +0000, Mark Rutland wrote:
> From: Ding Tianhong <dingtianhong@huawei.com>
> 
> Erratum Hisilicon-161010101 says that the ARM generic timer counter "has
> the potential to contain an erroneous value when the timer value
> changes". Accesses to TVAL (both read and write) are also affected due
> to the implicit counter read. Accesses to CVAL are not affected.
> 
> The workaround is to reread the system count registers until the value
> of the second read is larger than the first one by less than 32, the
> system counter can be guaranteed not to return wrong value twice by
> back-to-back read and the error value is always larger than the correct
> one by 32. Writes to TVAL are replaced with an equivalent write to CVAL.
> 
> Signed-off-by: Ding Tianhong <dingtianhong@huawei.com>
> [Mark: split patch, fix Kconfig, reword commit message]
> Signed-off-by: Mark Rutland <mark.rutland@arm.com>
> ---

Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>

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[PATCH 0/7] arm64: arch_timer: work around Hisilicon erratum 161010101 Mark Rutland <mark.rutland@arm.com> - 2017-01-31 13:30 +0100
  [PATCH 3/7] arm64: arm_arch_timer: remove fsl-a008585 parameter Mark Rutland <mark.rutland@arm.com> - 2017-01-31 13:30 +0100
    Re: [PATCH 3/7] arm64: arm_arch_timer: remove fsl-a008585 parameter Daniel Lezcano <daniel.lezcano@linaro.org> - 2017-02-01 11:10 +0100
  [PATCH 6/7] arm64: arch_timer: document Hisilicon erratum 161010101 Mark Rutland <mark.rutland@arm.com> - 2017-01-31 13:30 +0100
    Re: [PATCH 6/7] arm64: arch_timer: document Hisilicon erratum  161010101 Will Deacon <will.deacon@arm.com> - 2017-01-31 15:40 +0100
  [PATCH 5/7] arm64: arch_timer: work around Hisilicon erratum 161010101 Mark Rutland <mark.rutland@arm.com> - 2017-01-31 13:30 +0100
    Re: [PATCH 5/7] arm64: arch_timer: work around Hisilicon erratum  161010101 Mark Rutland <mark.rutland@arm.com> - 2017-02-02 19:50 +0100
    Re: [PATCH 5/7] arm64: arch_timer: work around Hisilicon erratum  161010101 Daniel Lezcano <daniel.lezcano@linaro.org> - 2017-02-02 20:30 +0100
  [PATCH 1/7] arm64: docs: widen silicon-errata kconfig column Mark Rutland <mark.rutland@arm.com> - 2017-01-31 13:30 +0100
  [PATCH 7/7] arm64: arch timer: Add timer erratum property for Hip05-d02 and Hip06-d03 Mark Rutland <mark.rutland@arm.com> - 2017-01-31 13:30 +0100
  [PATCH 4/7] arm64: arch_timer: introduce generic errata handling infrastructure Mark Rutland <mark.rutland@arm.com> - 2017-01-31 13:30 +0100
    Re: [PATCH 4/7] arm64: arch_timer: introduce generic errata handling  infrastructure Daniel Lezcano <daniel.lezcano@linaro.org> - 2017-02-01 11:20 +0100
    Re: [PATCH 4/7] arm64: arch_timer: introduce generic errata handling  infrastructure Daniel Lezcano <daniel.lezcano@linaro.org> - 2017-02-01 11:20 +0100
  [PATCH 2/7] arm64: arch_timer: add dt binding for hisilicon-161010101 erratum Mark Rutland <mark.rutland@arm.com> - 2017-01-31 13:30 +0100

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