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Re: [PATCH] clocksource/drivers/pistachio: Fix wrong calculated clocksource read value

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Dear Daniel,

On Tue, 15 Dec 2015 21:59:30 +0100 Daniel Lezcano wrote:

> On 11/25/2015 04:42 PM, Jisheng Zhang wrote:
> > Let's assume the counter value is 0xf000000, the pistachio clocksource
> > read cycles function would return 0xffffffff0fffffff, but it should
> > return 0xfffffff.
> >
> > We fix this issue by calculating bitwise-not counter, then cast to
> > cycle_t.
> >
> > Signed-off-by: Jisheng Zhang <jszhang@marvell.com>  
> 
> Hi Jisheng,
> 
> I tried to reproduce this behavior on x86_64 but without success.
> 
> On which architecture did you produce this result ? Do you have a simple 
> test program to check with ?

I have no HW platforms with pistachio, just read the code and run the
following test code in x86_64 and x86_32:

#include <stdio.h>
unsigned long long pistachio_clocksource_read_cycles()
{
	unsigned int counter = 0xf000000;
	return ~(unsigned long long)counter;
}
int main()
{
	printf("%llx\n", pistachio_clocksource_read_cycles());
	return 0;
}

Thanks,
Jisheng
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Re: [PATCH] clocksource/drivers/pistachio: Fix wrong calculated  clocksource read value Daniel Lezcano <daniel.lezcano@linaro.org> - 2015-12-15 22:00 +0100
  Re: [PATCH] clocksource/drivers/pistachio: Fix wrong calculated  clocksource read value Jisheng Zhang <jszhang@marvell.com> - 2015-12-16 08:20 +0100
    Re: [PATCH] clocksource/drivers/pistachio: Fix wrong calculated  clocksource read value Jisheng Zhang <jszhang@marvell.com> - 2015-12-16 08:40 +0100
      Re: [PATCH] clocksource/drivers/pistachio: Fix wrong calculated  clocksource read value Jisheng Zhang <jszhang@marvell.com> - 2015-12-16 08:50 +0100
        Re: [PATCH] clocksource/drivers/pistachio: Fix wrong calculated  clocksource read value Jisheng Zhang <jszhang@marvell.com> - 2015-12-16 09:00 +0100
        Re: [PATCH] clocksource/drivers/pistachio: Fix wrong calculated  clocksource read value Daniel Lezcano <daniel.lezcano@linaro.org> - 2015-12-16 10:30 +0100
          Re: [PATCH] clocksource/drivers/pistachio: Fix wrong calculated  clocksource read value Russell King - ARM Linux <linux@arm.linux.org.uk> - 2015-12-16 10:40 +0100
            Re: [PATCH] clocksource/drivers/pistachio: Fix wrong calculated  clocksource read value Russell King - ARM Linux <linux@arm.linux.org.uk> - 2015-12-16 11:40 +0100
              Re: [PATCH] clocksource/drivers/pistachio: Fix wrong calculated  clocksource read value Daniel Lezcano <daniel.lezcano@linaro.org> - 2015-12-16 17:30 +0100
              Re: [PATCH] clocksource/drivers/pistachio: Fix wrong calculated  clocksource read value Jisheng Zhang <jszhang@marvell.com> - 2015-12-17 10:20 +0100
            Re: [PATCH] clocksource/drivers/pistachio: Fix wrong calculated  clocksource read value Daniel Lezcano <daniel.lezcano@linaro.org> - 2015-12-16 11:40 +0100
      Re: [PATCH] clocksource/drivers/pistachio: Fix wrong calculated  clocksource read value Daniel Lezcano <daniel.lezcano@linaro.org> - 2015-12-16 10:10 +0100
    Re: [PATCH] clocksource/drivers/pistachio: Fix wrong calculated  clocksource read value Daniel Lezcano <daniel.lezcano@linaro.org> - 2015-12-16 10:10 +0100

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