[PATCH 1/2] ARM: EXYNOS4: convert MCT to percpu interrupt API

[MyungJoo Ham]

On Thu, Nov 10, 2011 at 6:43 PM, Marc Zyngier <marc.zyngier at arm.com> wrote:
> On 10/11/11 02:40, MyungJoo Ham wrote:
>> On Thu, Nov 3, 2011 at 2:30 AM, Marc Zyngier <marc.zyngier at arm.com> wrote:
>>> MCT recently gained per cpu interrupts, and missed the fact that
>>> ARM has moved to a genirq based implementation.
>>>
>>> This patch converts the driver to the new API.
>>>
>>> Boot tested on Origen.
>>>
>>> Cc: Kukjin Kim <kgene.kim at samsung.com>
>>> Signed-off-by: Marc Zyngier <marc.zyngier at arm.com>
>>
>> There is one concern regarding the CONFIG_LOCAL_TIMER.
>>
>> []
>>>  #endif /* CONFIG_LOCAL_TIMERS */
>>>
>>>  static void __init exynos4_timer_resources(void)
>>> @@ -438,6 +442,16 @@ static void __init exynos4_timer_resources(void)
>>>        mct_clk = clk_get(NULL, "xtal");
>>>
>>>        clk_rate = clk_get_rate(mct_clk);
>>> +
>>> +       if (mct_int_type == MCT_INT_PPI) {
>>> +               int err;
>>> +
>>> +               err = request_percpu_irq(IRQ_MCT_LOCALTIMER,
>>> +                                        exynos4_mct_tick_isr, "MCT",
>>> +                                        &percpu_mct_tick);
>>> +               WARN(err, "MCT: can't request IRQ %d (%d)\n",
>>> +                    IRQ_MCT_LOCALTIMER, err);
>>> +       }
>>>  }
>>>
>>
>> You've added exynos4_mct_tick_isr, which is defined in
>> CONFIG_LOCAL_TIMER section, in the place that is compiled without
>> CONFIG_LOCAL_TIMER.
>> I guess we are going to stop supporting LOCAL_TIMER in Exynos later
>> and this could be a problem with it.
>
> Yup, this is a problem. It probably means we need to #ifdef that chink
> as well. I'm not sure I get your remark about not supporting LOCAL_TIMER
> though. Are you planning to move away from the LOCAL_TIMER infrastructure?

Yes, we may need to #ifdef that block.
And yes, for the Exynos series, I'll need to double check; however, I
think we are planning to move away from the LOCAL_TIMER for MCT.

>
> If that's the case, you might as well know that my pet plan is to get
> rid of the LOCAL_TIMER option altogether, and move to a model where each
> timer driver is (sort of) autonomous, instead of being driven by the SMP
> code.
>
>        M.
> --
> Jazz is not dead. It just smells funny...
>
>

Cheers!
MyungJoo

-- 
MyungJoo Ham, Ph.D.
Mobile Software Platform Lab, DMC Business, Samsung Electronics