linux-kernel - Re: [PATCH] microblaze/timer: set ->min_delta_ticks and ->max_delta

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Message-ID: <87h91pkr0w.fsf@gmail.com>
Date:   Sun, 16 Apr 2017 04:47:11 +0200
From:   Nicolai Stange <nicstange@...il.com>
To:     Daniel Lezcano <daniel.lezcano@...aro.org>
Cc:     Nicolai Stange <nicstange@...il.com>,
        Michal Simek <monstr@...str.eu>,
        John Stultz <john.stultz@...aro.org>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] microblaze/timer: set ->min_delta_ticks and ->max_delta_ticks

Hello Daniel,

On Fri, Apr 07 2017, Daniel Lezcano wrote:

> On Thu, Mar 30, 2017 at 09:45:28PM +0200, Nicolai Stange wrote:
>> diff --git a/arch/microblaze/kernel/timer.c b/arch/microblaze/kernel/timer.c
>> index 999066192715..545ccd46edb3 100644
>> --- a/arch/microblaze/kernel/timer.c
>> +++ b/arch/microblaze/kernel/timer.c
>> @@ -178,8 +178,10 @@ static __init int xilinx_clockevent_init(void)
>>  				clockevent_xilinx_timer.shift);
>>  	clockevent_xilinx_timer.max_delta_ns =
>>  		clockevent_delta2ns((u32)~0, &clockevent_xilinx_timer);
>> +	clockevent_xilinx_timer.max_delta_ticks = (u32)~0;
>
> Can you take the opportunity to fix the type (unsigned long) ?

Hmm, I personally think that it'd be better to leave the u32 there as it
corresponds to the hardware's counter width?

clockevent_delta2ns()' latch argument has been of type unsigned long
from the beginning and this might indicate that at least this
driver's original author followed this line of reasoning...

OTOH, I think that u32 is equivalent to unsigned long on microblaze, so
it doesn't matter much.

Does the above convince you or do you still want the

  -	clockevent_xilinx_timer.max_delta_ticks = (u32)~0;
  +	clockevent_xilinx_timer.max_delta_ticks = ~0UL;

change?


Thanks,

Nicolai