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Re: [PATCH v23 06/11] clocksource: arm_arch_timer: refactor MMIO timer probing.

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Hi Mark,

On 6 April 2017 at 02:42, Mark Rutland <mark.rutland@arm.com> wrote:
> On Sat, Apr 01, 2017 at 01:51:00AM +0800, fu.wei@linaro.org wrote:
>> +     arch_timer_mem_freq = arch_timer_mem_get_cntfrq(base);
>> +     if (!arch_timer_rate && arch_timer_mem_freq) {
>> +             arch_timer_rate = arch_timer_mem_freq;
>> +     } else if (!arch_timer_rate || arch_timer_rate != arch_timer_mem_freq) {
>> +             pr_err(FW_BUG "invalid MMIO frequency.\n");
>> +             iounmap(base);
>> +             return -EINVAL;
>> +     }
>
> I thought I had previously mentioned that this last check has the
> potential to break DT systems, which may be inadvertently relying on the
> probe order.
>
> I agree we must do this check for ACPI, but I think that for DT it needs
> to be relaxed.
>
> I'm happy to rework that locally, if you can address my comments on
> patch 9.

yes, you suggested that we keep the current frequency probing approach for DT,
and use the new approach for ACPI.

Because we try to merge the common code for MMIO timer. this become a little
problem, sorry for that.

I thinks for this code, maybe we can do :

arch_timer_mem_freq = arch_timer_mem_get_cntfrq(base);
if (!arch_timer_rate && arch_timer_mem_freq) {
arch_timer_rate = arch_timer_mem_freq;
} else if (!acpi_disabled && arch_timer_rate != arch_timer_mem_freq) {
pr_err(FW_BUG "invalid MMIO frequency.\n");
iounmap(base);
return -EINVAL;
}

Please correct me, if I miss something.

Thanks :-)

>
> Thanks,
> Mark.



-- 
Best regards,

Fu Wei
Software Engineer
Red Hat

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[PATCH v23 00/11] acpi, clocksource: add GTDT driver and GTDT support in arm_arch_timer fu.wei@linaro.org - 2017-03-31 20:00 +0200
  [PATCH v23 06/11] clocksource: arm_arch_timer: refactor MMIO timer probing. fu.wei@linaro.org - 2017-03-31 20:00 +0200
    Re: [PATCH v23 06/11] clocksource: arm_arch_timer: refactor MMIO  timer probing. Mark Rutland <mark.rutland@arm.com> - 2017-04-05 20:50 +0200
      Re: [PATCH v23 06/11] clocksource: arm_arch_timer: refactor MMIO  timer probing. Fu Wei <fu.wei@linaro.org> - 2017-04-06 12:50 +0200
  [PATCH v23 04/11] clocksource: arm_arch_timer: move arch_timer_needs_of_probing into DT init call fu.wei@linaro.org - 2017-03-31 20:00 +0200
  [PATCH v23 08/11] clocksource: arm_arch_timer: simplify ACPI support code. fu.wei@linaro.org - 2017-03-31 20:00 +0200
  [PATCH v23 09/11] acpi/arm64: Add memory-mapped timer support in GTDT driver fu.wei@linaro.org - 2017-03-31 20:00 +0200
    Re: [PATCH v23 09/11] acpi/arm64: Add memory-mapped timer support in  GTDT driver Will Deacon <will.deacon@arm.com> - 2017-04-03 11:50 +0200
    Re: [PATCH v23 09/11] acpi/arm64: Add memory-mapped timer support in  GTDT driver Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> - 2017-04-03 12:50 +0200
      Re: [PATCH v23 09/11] acpi/arm64: Add memory-mapped timer support in  GTDT driver Fu Wei <fu.wei@linaro.org> - 2017-04-06 19:20 +0200
    Re: [PATCH v23 09/11] acpi/arm64: Add memory-mapped timer support in  GTDT driver Mark Rutland <mark.rutland@arm.com> - 2017-04-05 20:40 +0200
      Re: [PATCH v23 09/11] acpi/arm64: Add memory-mapped timer support in  GTDT driver Mark Rutland <mark.rutland@arm.com> - 2017-04-06 12:10 +0200
      Re: [PATCH v23 09/11] acpi/arm64: Add memory-mapped timer support in  GTDT driver Fu Wei <fu.wei@linaro.org> - 2017-04-06 18:50 +0200
        Re: [PATCH v23 09/11] acpi/arm64: Add memory-mapped timer support in  GTDT driver Mark Rutland <mark.rutland@arm.com> - 2017-04-06 19:30 +0200
          Re: [PATCH v23 09/11] acpi/arm64: Add memory-mapped timer support in  GTDT driver Fu Wei <fu.wei@linaro.org> - 2017-04-06 19:50 +0200
            Re: [PATCH v23 09/11] acpi/arm64: Add memory-mapped timer support in  GTDT driver Mark Rutland <mark.rutland@arm.com> - 2017-04-06 20:00 +0200
              Re: [PATCH v23 09/11] acpi/arm64: Add memory-mapped timer support in  GTDT driver Fu Wei <fu.wei@linaro.org> - 2017-04-06 20:10 +0200
  [PATCH v23 07/11] acpi/arm64: Add GTDT table parse driver fu.wei@linaro.org - 2017-03-31 20:00 +0200
  [PATCH v23 05/11] clocksource: arm_arch_timer: add structs to describe MMIO timer fu.wei@linaro.org - 2017-03-31 20:00 +0200
  [PATCH v23 01/11] clocksource: arm_arch_timer: add MMIO CNTFRQ helper fu.wei@linaro.org - 2017-03-31 20:00 +0200
  [PATCH v23 11/11] acpi/arm64: Add SBSA Generic Watchdog support in GTDT driver fu.wei@linaro.org - 2017-03-31 20:00 +0200
  [PATCH v23 02/11] clocksource: arm_arch_timer: split dt-only rate handling fu.wei@linaro.org - 2017-03-31 20:00 +0200
  [PATCH v23 03/11] clocksource: arm_arch_timer: refactor arch_timer_needs_probing fu.wei@linaro.org - 2017-03-31 20:00 +0200
  Re: [PATCH v23 00/11] acpi, clocksource: add GTDT driver and GTDT  support in arm_arch_timer Xiongfeng Wang <wangxiongfeng2@huawei.com> - 2017-04-01 04:20 +0200
    Re: [PATCH v23 00/11] acpi, clocksource: add GTDT driver and GTDT  support in arm_arch_timer Fu Wei <fu.wei@linaro.org> - 2017-04-01 05:50 +0200
  Re: [PATCH v23 00/11] acpi, clocksource: add GTDT driver and GTDT  support in arm_arch_timer Timur Tabi <timur@codeaurora.org> - 2017-04-04 22:40 +0200

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