[PATCH] cpuidle: add freescale e500 family porcessors idle support

[Dongsheng.Wang at freescale.com]

Hi Daniel,

Thanks for your review. I will fix your comments.

BTW, fix Rafael's email. :)

> > +#include <linux/cpu.h>
> > +#include <linux/cpuidle.h>
> > +#include <linux/init.h>
> > +#include <linux/kernel.h>
> > +#include <linux/notifier.h>
> > +
> > +#include <asm/cputable.h>
> > +#include <asm/machdep.h>
> > +#include <asm/mpc85xx.h>
> > +
> > +static unsigned int max_idle_state;
> > +static struct cpuidle_state *cpuidle_state_table;
> > +
> > +struct cpuidle_driver e500_idle_driver = {
> > +	.name = "e500_idle",
> > +	.owner = THIS_MODULE,
> > +};
> > +
> > +static void e500_cpuidle(void)
> > +{
> > +	if (cpuidle_idle_call())
> > +		cpuidle_wait();
> > +}
> 
> Nope, that has been changed. No more call to cpuidle_idle_call in a driver.
> 

Thanks.

> > +
> > +static int pw10_enter(struct cpuidle_device *dev,
> > +			struct cpuidle_driver *drv, int index)
> > +{
> > +	cpuidle_wait();
> > +	return index;
> > +}
> > +
> > +#define MAX_BIT	63
> > +#define MIN_BIT	1
> > +extern u32 cpuidle_entry_bit;
> > +static int pw20_enter(struct cpuidle_device *dev,
> > +		struct cpuidle_driver *drv, int index)
> > +{
> > +	u32 pw20_idle;
> > +	u32 entry_bit;
> > +	pw20_idle = mfspr(SPRN_PWRMGTCR0);
> > +	if ((pw20_idle & PWRMGTCR0_PW20_ENT) != PWRMGTCR0_PW20_ENT) {
> > +		pw20_idle &= ~PWRMGTCR0_PW20_ENT;
> > +		entry_bit = MAX_BIT - cpuidle_entry_bit;
> > +		pw20_idle |= (entry_bit << PWRMGTCR0_PW20_ENT_SHIFT);
> > +		mtspr(SPRN_PWRMGTCR0, pw20_idle);
> > +	}
> > +
> > +	cpuidle_wait();
> > +
> > +	pw20_idle &= ~PWRMGTCR0_PW20_ENT;
> > +	pw20_idle |= (MIN_BIT << PWRMGTCR0_PW20_ENT_SHIFT);
> > +	mtspr(SPRN_PWRMGTCR0, pw20_idle);
> > +
> > +	return index;
> > +}
> 
> Is it possible to give some comments and encapsulate the code with
> explicit function names to be implemented in an arch specific directory
> file (eg. pm.c) and export these functions in a linux/ header ? We try
> to prevent to include asm if possible.
> 

Yep, Looks better. Thanks.

> > +
> > +static struct cpuidle_state pw_idle_states[] = {
> > +	{
> > +		.name = "pw10",
> > +		.desc = "pw10",
> > +		.flags = CPUIDLE_FLAG_TIME_VALID,
> > +		.exit_latency = 0,
> > +		.target_residency = 0,
> > +		.enter = &pw10_enter
> > +	},
> > +
> > +	{
> > +		.name = "pw20",
> > +		.desc = "pw20-core-idle",
> > +		.flags = CPUIDLE_FLAG_TIME_VALID,
> > +		.exit_latency = 1,
> > +		.target_residency = 50,
> > +		.enter = &pw20_enter
> > +	},
> > +};
> 
> No need to define this intermediate structure here, you can directly
> initialize the cpuidle_driver:
> 

Thanks. :)

> > +static int cpu_hotplug_notify(struct notifier_block *n,
> > +			unsigned long action, void *hcpu)
> > +{
> > +	unsigned long hotcpu = (unsigned long)hcpu;
> > +	struct cpuidle_device *dev =
> > +			per_cpu_ptr(cpuidle_devices, hotcpu);
> > +
> > +	if (dev && cpuidle_get_driver()) {
> > +		switch (action) {
> > +		case CPU_ONLINE:
> > +		case CPU_ONLINE_FROZEN:
> > +			cpuidle_pause_and_lock();
> > +			cpuidle_enable_device(dev);
> > +			cpuidle_resume_and_unlock();
> > +			break;
> > +
> > +		case CPU_DEAD:
> > +		case CPU_DEAD_FROZEN:
> > +			cpuidle_pause_and_lock();
> > +			cpuidle_disable_device(dev);
> > +			cpuidle_resume_and_unlock();
> > +			break;
> > +
> > +		default:
> > +			return NOTIFY_DONE;
> > +		}
> > +	}
> > +
> > +	return NOTIFY_OK;
> > +}
> > +
> > +static struct notifier_block cpu_hotplug_notifier = {
> > +	.notifier_call = cpu_hotplug_notify,
> > +};
> 
> Can you explain why this is needed ?
> 

If a cpu will be plugged out/in, We should be let Cpuidle know to remove
corresponding sys interface and disable/enable cpudile-governor for current cpu.

> > +	err = register_cpu_notifier(&cpu_hotplug_notifier);
> > +	if (err)
> > +		pr_warn("Cpuidle driver: register cpu notifier failed.\n");
> > +
> > +	/* Replace the original way of idle after cpuidle registered. */
> > +	ppc_md.power_save = e500_cpuidle;
> > +	on_each_cpu(replace_orig_idle, NULL, 1);
> 
> Why ?
> 

I checked again, if we put cpuidle_idle_call in asm, this is not need.

Regards,
-Dongsheng

> > +	pr_info("e500_idle_driver registered.\n");
> > +
> > +	return 0;
> > +}
> > +late_initcall(e500_idle_init);
> >
> 
> Thanks
> 
>    -- Daniel
> 
> 
> --
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