On 07/29/2013 04:27 PM, Deepthi Dharwar wrote:
> 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.
Hi Deepthi,
ok may be there is some difference with the other platform but the
arch_cpu_idle function defined in the other archs do:
void arch_cpu_idle(void)
{
if (cpuidle_idle_call())
x86_idle();
else
local_irq_enable();
}
or
void arch_cpu_idle(void)
{
if (cpuidle_idle_call())
default_idle();
}
When the cpuidle driver is not compiled or not loaded, cpuidle_idle_call
fails, falling back to the default idle function.
The arch_cpu_idle function is called from the generic code in
kernel/cpu/idle.c.
Is there a particular reason to do it in a different way ?
Thanks
-- Daniel
>>
>>> Signed-off-by: Deepthi Dharwar <deepthi@xxxxxxxxxxxxxxxxxx>
>>> ---
>>> 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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>>
>>
>
--
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