[PATCH 5/5] ARM: exynos: enable/disable cpuidle when cpu1 is down/up
amit daniel kachhap
amit.daniel at samsung.com
Thu Jan 10 15:07:52 EST 2013
Hi 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 also which
is required. Other patches look good.
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
>
>
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