[PATCH 5/5] ARM: exynos: enable/disable cpuidle when cpu1 is down/up
amit daniel kachhap
amit.daniel at samsung.com
Thu Jan 10 17:33:21 EST 2013
On Thu, Jan 10, 2013 at 1:32 PM, Daniel Lezcano <daniel.lezcano at free.fr> wrote:
> On 01/10/2013 09:07 PM, amit daniel kachhap wrote:
>> Hi Daniel,
>
> Hi Amit Daniel,
>
>> This hotplug noifiers looks fine. I suppose it should add extra state
>> C1 in cpu0. If it is done like below than for normal cases(when all
>> cpu's are online) there wont be any statistics for C0 state
>
> I guess you meant state 0 which is WFI, right ?
> C0 state is the intel semantic for cpu fully turned on.
Yes I meant C0 as wfi
>
>> also which
>> is required. Other patches look good.
>
> Ok, that makes sense to have statistics even if they are only doing WFI.
>
> Then the patch 4/5 is not ok, no ?
yes I suppose patch 4 and patch 5 are related and depends how you
frame patch 5. I think it is better to create C0/C1 sysfs and other
things in the beginning because it is a filesystem call and may
increase the cpu hotplug time which is not worth. May be if cpuidle
framework exposes some API to enable/disable states then it is better.
For patch 1,2 and 3,
Acked-by: Amit Daniel Kachhap <amit.daniel at samsung.com>
Thanks,
Amit Daniel
>
> Thanks for review
> -- Daniel
>
>>
>> Thanks,
>> Amit
>>
>> On Fri, Jan 4, 2013 at 8:59 AM, Daniel Lezcano
>> <daniel.lezcano at linaro.org> wrote:
>>> What we have now is (1) cpu0 going always to WFI when cpu1 is up,
>>> (2) cpu0 going to all states when cpu1 is down.
>>>
>>> In other words, cpuidle is disabled when cpu1 is up and enabled
>>> when cpu1 is down.
>>>
>>> This patch use the cpu hotplug notifier to enable/disable cpuidle,
>>> when the cpu1 is plugged or unplugged. That clarifies the code and
>>> make it simpler.
>>>
>>> Signed-off: Daniel Lezcano <daniel.lezcano at linaro.org>
>>> ---
>>> arch/arm/mach-exynos/cpuidle.c | 117 +++++++++++++++++++++++-----------------
>>> 1 file changed, 69 insertions(+), 48 deletions(-)
>>>
>>> diff --git a/arch/arm/mach-exynos/cpuidle.c b/arch/arm/mach-exynos/cpuidle.c
>>> index e6f006b..d8f6f33 100644
>>> --- a/arch/arm/mach-exynos/cpuidle.c
>>> +++ b/arch/arm/mach-exynos/cpuidle.c
>>> @@ -12,6 +12,8 @@
>>> #include <linux/init.h>
>>> #include <linux/cpuidle.h>
>>> #include <linux/cpu_pm.h>
>>> +#include <linux/notifier.h>
>>> +#include <linux/cpu.h>
>>> #include <linux/io.h>
>>> #include <linux/export.h>
>>> #include <linux/time.h>
>>> @@ -36,31 +38,8 @@
>>>
>>> #define S5P_CHECK_AFTR 0xFCBA0D10
>>>
>>> -static int exynos4_enter_lowpower(struct cpuidle_device *dev,
>>> - struct cpuidle_driver *drv,
>>> - int index);
>>> -
>>> static struct cpuidle_device exynos4_cpuidle_device;
>>>
>>> -static struct cpuidle_driver exynos4_idle_driver = {
>>> - .name = "exynos4_idle",
>>> - .owner = THIS_MODULE,
>>> - .en_core_tk_irqen = 1,
>>> - .states = {
>>> - [0] = ARM_CPUIDLE_WFI_STATE,
>>> - [1] = {
>>> - .enter = exynos4_enter_lowpower,
>>> - .exit_latency = 300,
>>> - .target_residency = 100000,
>>> - .flags = CPUIDLE_FLAG_TIME_VALID,
>>> - .name = "C1",
>>> - .desc = "ARM power down",
>>> - },
>>> - },
>>> - .state_count = 2,
>>> - .safe_state_index = 0,
>>> -};
>>> -
>>> /* Ext-GIC nIRQ/nFIQ is the only wakeup source in AFTR */
>>> static void exynos4_set_wakeupmask(void)
>>> {
>>> @@ -93,9 +72,9 @@ static int idle_finisher(unsigned long flags)
>>> return 1;
>>> }
>>>
>>> -static int exynos4_enter_core0_aftr(struct cpuidle_device *dev,
>>> - struct cpuidle_driver *drv,
>>> - int index)
>>> +static int exynos4_enter_lowpower(struct cpuidle_device *dev,
>>> + struct cpuidle_driver *drv,
>>> + int index)
>>> {
>>> unsigned long tmp;
>>>
>>> @@ -143,22 +122,6 @@ static int exynos4_enter_core0_aftr(struct cpuidle_device *dev,
>>> return index;
>>> }
>>>
>>> -static int exynos4_enter_lowpower(struct cpuidle_device *dev,
>>> - struct cpuidle_driver *drv,
>>> - int index)
>>> -{
>>> - int new_index = index;
>>> -
>>> - /* This mode only can be entered when other core's are offline */
>>> - if (num_online_cpus() > 1)
>>> - new_index = drv->safe_state_index;
>>> -
>>> - if (new_index == 0)
>>> - return arm_cpuidle_simple_enter(dev, drv, new_index);
>>> - else
>>> - return exynos4_enter_core0_aftr(dev, drv, new_index);
>>> -}
>>> -
>>> static void __init exynos5_core_down_clk(void)
>>> {
>>> unsigned int tmp;
>>> @@ -191,6 +154,62 @@ static void __init exynos5_core_down_clk(void)
>>> __raw_writel(tmp, EXYNOS5_PWR_CTRL2);
>>> }
>>>
>>> +static int cpu_hotplug_notify(struct notifier_block *n,
>>> + unsigned long action, void *hcpu)
>>> +{
>>> + int ret;
>>> +
>>> + /*
>>> + * cpu0 can't be shutdown on Origen, so this routine is
>>> + * called only for cpu1.
>>> + */
>>> +
>>> + switch (action & 0xf) {
>>> +
>>> + case CPU_ONLINE:
>>> + cpuidle_pause_and_lock();
>>> + cpuidle_disable_device(&exynos4_cpuidle_device);
>>> + cpuidle_resume_and_unlock();
>>> + break;
>>> +
>>> + case CPU_DEAD:
>>> + if (!exynos4_cpuidle_device.registered) {
>>> + ret = cpuidle_register_device(&exynos4_cpuidle_device);
>>> + WARN_ONCE(ret, "Failed to register cpuidle device");
>>> + } else {
>>> + cpuidle_pause_and_lock();
>>> + cpuidle_enable_device(&exynos4_cpuidle_device);
>>> + cpuidle_resume_and_unlock();
>>> + }
>>> + break;
>>> + }
>>> +
>>> + return NOTIFY_OK;
>>> +}
>>> +
>>> +static struct notifier_block cpu_hotplug_notifier = {
>>> + .notifier_call = cpu_hotplug_notify,
>>> +};
>>> +
>>> +static struct cpuidle_driver exynos4_idle_driver = {
>>> + .name = "exynos4_idle",
>>> + .owner = THIS_MODULE,
>>> + .en_core_tk_irqen = 1,
>>> + .states = {
>>> + [0] = ARM_CPUIDLE_WFI_STATE,
>>> + [1] = {
>>> + .enter = exynos4_enter_lowpower,
>>> + .exit_latency = 300,
>>> + .target_residency = 100000,
>>> + .flags = CPUIDLE_FLAG_TIME_VALID,
>>> + .name = "C1",
>>> + .desc = "ARM power down",
>>> + },
>>> + },
>>> + .state_count = 2,
>>> + .safe_state_index = 0,
>>> +};
>>> +
>>> static int __init exynos4_init_cpuidle(void)
>>> {
>>> int ret;
>>> @@ -204,12 +223,14 @@ static int __init exynos4_init_cpuidle(void)
>>> return ret;
>>> }
>>>
>>> - ret = cpuidle_register_device(&exynos4_cpuidle_device);
>>> - if (ret) {
>>> - printk(KERN_ERR "CPUidle register device failed\n");
>>> - return ret;
>>> - }
>>> + ret = register_cpu_notifier(&cpu_hotplug_notifier);
>>> + if (ret)
>>> + goto out_unregister_driver;
>>> +out:
>>> + return ret;
>>>
>>> - return 0;
>>> +out_unregister_driver:
>>> + cpuidle_unregister_driver(&exynos4_idle_driver);
>>> + goto out;
>>> }
>>> device_initcall(exynos4_init_cpuidle);
>>> --
>>> 1.7.9.5
>>>
>>>
>>> _______________________________________________
>>> linaro-dev mailing list
>>> linaro-dev at lists.linaro.org
>>> http://lists.linaro.org/mailman/listinfo/linaro-dev
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>
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