Subject: Re: [PATCH 2/3] cpuidle/powernv: Enable idle powernv cpu to call into the cpuidle framework.

From: Deepthi Dharwar <[email-masked]>
Date: Mon, 29 Jul 2013 19:57:49 +0530

On 07/27/2013 10:59 AM, Daniel Lezcano wrote:
> On 07/23/2013 11:01 AM, Deepthi Dharwar wrote:
>> This patch enables idle powernv cpu to hook on to the cpuidle
>> framework, if available, else call on to default idle platform
>> code.
> 
> Why do you need to do that ?
> 

Hi Daniel,

Well, this is needed in case when one does not compile with CPU_IDLE
config option.

When CPUIDLE is not configured, idle cpus are needed to be running some
sort of default idle code or loop ( in the worst case) if cpuidle driver
is not registered or if one decides not to have that config enabled.

Regards,
Deepthi

> 
>> Signed-off-by: Deepthi Dharwar <[email-masked]>
>> ---
>>  arch/powerpc/platforms/powernv/setup.c |   12 +++++++++++-
>>  1 file changed, 11 insertions(+), 1 deletion(-)
>>
>> diff --git a/arch/powerpc/platforms/powernv/setup.c b/arch/powerpc/platforms/powernv/setup.c
>> index 84438af..97d0951 100644
>> --- a/arch/powerpc/platforms/powernv/setup.c
>> +++ b/arch/powerpc/platforms/powernv/setup.c
>> @@ -25,6 +25,7 @@
>>  #include <linux/of.h>
>>  #include <linux/interrupt.h>
>>  #include <linux/bug.h>
>> +#include <linux/cpuidle.h>
>>  
>>  #include <asm/machdep.h>
>>  #include <asm/firmware.h>
>> @@ -196,6 +197,15 @@ static int __init pnv_probe(void)
>>  	return 1;
>>  }
>>  
>> +void powernv_idle(void)
>> +{
>> +	/* Hook to cpuidle framework if available, else
>> +	 * call on default platform idle code
>> +	 */
>> +	if (cpuidle_idle_call())
>> +		power7_idle();
>> +}
>> +
>>  define_machine(powernv) {
>>  	.name			= "PowerNV",
>>  	.probe			= pnv_probe,
>> @@ -205,7 +215,7 @@ define_machine(powernv) {
>>  	.show_cpuinfo		= pnv_show_cpuinfo,
>>  	.progress		= pnv_progress,
>>  	.machine_shutdown	= pnv_shutdown,
>> -	.power_save             = power7_idle,
>> +	.power_save             = powernv_idle,
>>  	.calibrate_decr		= generic_calibrate_decr,
>>  #ifdef CONFIG_KEXEC
>>  	.kexec_cpu_down		= pnv_kexec_cpu_down,
>>
>> --
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> 
>