linux-kernel - Re: [PATCH v3 0/6] clocksource: rework Atmel TCB timer driver

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Date:   Thu, 29 Mar 2018 14:07:34 +0200
From:   Daniel Lezcano <daniel.lezcano@...aro.org>
To:     Alexandre Belloni <alexandre.belloni@...tlin.com>,
        Alexander Dahl <ada@...rsis.com>
Cc:     linux-arm-kernel@...ts.infradead.org,
        Boris Brezillon <boris.brezillon@...tlin.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 0/6] clocksource: rework Atmel TCB timer driver

On 29/03/2018 13:42, Alexandre Belloni wrote:
> On 29/03/2018 at 13:31:18 +0200, Alexander Dahl wrote:
>> Pretty sure. I rebuilt the whole BSP and added another line to the kernel 
>> source to see if the tree I applied the patches to, was actually built:
>>
>>
>> diff --git a/drivers/clocksource/timer-atmel-tcb.c b/drivers/clocksource/timer-atmel-tcb.c
>> index 7fde9cfbf203..f85affc74a86 100644
>> --- a/drivers/clocksource/timer-atmel-tcb.c
>> +++ b/drivers/clocksource/timer-atmel-tcb.c
>> @@ -222,7 +222,8 @@ static int __init tc_clkevt_register(struct device_node *node,
>>                 goto err_slow;
>>         clk_disable(tce.clk);
>>  
>> -       clockevents_config_and_register(&tce.clkevt, 32768, 1, bits - 1);
>> +       pr_info( "*** bits: 0x%x, BIT(bits): 0x%lx\n", bits, BIT(bits) );
>> +       clockevents_config_and_register(&tce.clkevt, 32768, 1, BIT(bits) - 1);
>>  
>>         ret = request_irq(tce.irq, tc_clkevt2_irq, IRQF_TIMER | IRQF_SHARED,
>>                           tce.clkevt.name, &tce);
>>
>>
> 
> I've just tested on a g20, old driver:
> INT                NAME          RATE             MAX
>  16 [vel     at91_tick,]   175 Ints/s     (max:   231)
>  19 [ vel     tc_clkevt]   129 Ints/s     (max:   129)
> 
> 
> new driver:
> INT                NAME          RATE             MAX
>  17 [vel     timer@...a]   129 Ints/s     (max:   129)
>  18 [     vel     ttyS0]   175 Ints/s     (max:   231)

Can you give in both platforms how fast the clocksource wraps up ?

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