Re: [PATCH v9 4/9] clocksource/drivers/arm_arch_timer: use readq to get 64-bit CNTVCT

From	Timur Tabi <timur@codeaurora.org>
Newsgroups	linux.kernel
Subject	Re: [PATCH v9 4/9] clocksource/drivers/arm_arch_timer: use readq to get 64-bit CNTVCT
Date	2016-07-25 18:00 +0200
Message-ID	<rYQsq-6og-29@gated-at.bofh.it> (permalink)
References	<rYPZo-6e9-11@gated-at.bofh.it> <rYPZo-6e9-41@gated-at.bofh.it> <rYQ93-6hx-15@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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Will Deacon wrote:
>> >  {
>> >-	u32 vct_lo, vct_hi, tmp_hi;
>> >-
>> >-	do {
>> >-		vct_hi = readl_relaxed(arch_counter_base + CNTVCT_HI);
>> >-		vct_lo = readl_relaxed(arch_counter_base + CNTVCT_LO);
>> >-		tmp_hi = readl_relaxed(arch_counter_base + CNTVCT_HI);
>> >-	} while (vct_hi != tmp_hi);
>> >-
>> >-	return ((u64) vct_hi << 32) | vct_lo;
>> >+	return readq(arch_counter_base + CNTVCT_LO);
> Please drop this patch. It doesn't work.

On systems where readq() does work, wouldn't it be more optimal than the 
above while-loop?

-- 
Sent by an employee of the Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the
Code Aurora Forum, hosted by The Linux Foundation.

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[PATCH v9 4/9] clocksource/drivers/arm_arch_timer: use readq to get 64-bit CNTVCT fu.wei@linaro.org - 2016-07-25 17:30 +0200
  Re: [PATCH v9 4/9] clocksource/drivers/arm_arch_timer: use readq to  get 64-bit CNTVCT Will Deacon <will.deacon@arm.com> - 2016-07-25 17:40 +0200
    Re: [PATCH v9 4/9] clocksource/drivers/arm_arch_timer: use readq to  get 64-bit CNTVCT Fu Wei <fu.wei@linaro.org> - 2016-07-25 18:00 +0200
      Re: [PATCH v9 4/9] clocksource/drivers/arm_arch_timer: use readq to  get 64-bit CNTVCT Will Deacon <will.deacon@arm.com> - 2016-07-25 18:40 +0200
        Re: [PATCH v9 4/9] clocksource/drivers/arm_arch_timer: use readq to  get 64-bit CNTVCT Russell King - ARM Linux <linux@armlinux.org.uk> - 2016-07-26 01:00 +0200
          Re: [PATCH v9 4/9] clocksource/drivers/arm_arch_timer: use readq to  get 64-bit CNTVCT Fu Wei <fu.wei@linaro.org> - 2016-07-26 11:30 +0200
        Re: [PATCH v9 4/9] clocksource/drivers/arm_arch_timer: use readq to  get 64-bit CNTVCT Timur Tabi <timur@codeaurora.org> - 2016-07-26 16:20 +0200
          Re: [PATCH v9 4/9] clocksource/drivers/arm_arch_timer: use readq to  get 64-bit CNTVCT Jisheng Zhang <jszhang@marvell.com> - 2016-07-27 05:40 +0200
            Re: [PATCH v9 4/9] clocksource/drivers/arm_arch_timer: use readq to  get 64-bit CNTVCT Fu Wei <fu.wei@linaro.org> - 2016-07-27 06:20 +0200
          Re: [PATCH v9 4/9] clocksource/drivers/arm_arch_timer: use readq to  get 64-bit CNTVCT Will Deacon <will.deacon@arm.com> - 2016-07-28 16:00 +0200
    Re: [PATCH v9 4/9] clocksource/drivers/arm_arch_timer: use readq to  get 64-bit CNTVCT Timur Tabi <timur@codeaurora.org> - 2016-07-25 18:00 +0200

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