Re: [PATCH v5 21/29] nios2: Time keeping

From: Ley Foon Tan
Date: Thu Oct 30 2014 - 05:04:07 EST


On Tue, Oct 28, 2014 at 11:15 PM, Thomas Gleixner <tglx@xxxxxxxxxxxxx> wrote:
> On Tue, 28 Oct 2014, Ley Foon Tan wrote:
>> On Sel, 2014-10-28 at 10:23 +0100, Arnd Bergmann wrote:
>> > On Tuesday 28 October 2014 10:46:29 Ley Foon Tan wrote:
>> > > On Sun, Oct 26, 2014 at 5:10 AM, Thomas Gleixner <tglx@xxxxxxxxxxxxx> wrote:
>> > > > On Fri, 24 Oct 2014, Ley Foon Tan wrote:
>> > > >> +#ifndef _ASM_NIOS2_TIMEX_H
>> > > >> +#define _ASM_NIOS2_TIMEX_H
>> > > >> +
>> > > >> +typedef unsigned long cycles_t;
>> > > >> +
>> > > >> +extern cycles_t get_cycles(void);
>> > > >> +
>> > > >> +#define ARCH_HAS_READ_CURRENT_TIMER
>> > > >
>> > > > Why does NIOS need that? Does it have a hardware implementation
>> > > > dependent clock frequency which needs to be calibrated at boot time?
>> > > This is suggestion from Arnd to use read_current_timer instead of using
>> > > expensive delay loop calibration during boot.
>> >
>> > My mistake, sorry. I think the right way is to define
>> > calibrate_delay_is_known() rather than read_current_timer(), I was
>> > getting confused by the ARM implementation that does both.
>> Hi Arnd,
>> No problem, I can change that. But, seem that we don't need to have
>> calibrate_delay_is_known() as well. We can just set "lpj_fine" variable,
>> arm64 uses this.
>
> Please do so and resend the result so I can have another look and add
> my reviewed tag then.
Sure, I will send another revision.

Thanks for reviewing.

Regards
Ley Foon
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