[deliverable/linux.git] / drivers / cpuidle / cpuidle-powernv.c

/*
 *  cpuidle-powernv - idle state cpuidle driver.
 *  Adapted from drivers/cpuidle/cpuidle-pseries
 *
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/moduleparam.h>
#include <linux/cpuidle.h>
#include <linux/cpu.h>
#include <linux/notifier.h>

#include <asm/machdep.h>
#include <asm/firmware.h>
#include <asm/runlatch.h>

struct cpuidle_driver powernv_idle_driver = {
	.name             = "powernv_idle",
	.owner            = THIS_MODULE,
};

static int max_idle_state;
static struct cpuidle_state *cpuidle_state_table;

static int snooze_loop(struct cpuidle_device *dev,
			struct cpuidle_driver *drv,
			int index)
{
	local_irq_enable();
	set_thread_flag(TIF_POLLING_NRFLAG);

	ppc64_runlatch_off();
	while (!need_resched()) {
		HMT_low();
		HMT_very_low();
	}

	HMT_medium();
	ppc64_runlatch_on();
	clear_thread_flag(TIF_POLLING_NRFLAG);
	smp_mb();
	return index;
}

static int nap_loop(struct cpuidle_device *dev,
			struct cpuidle_driver *drv,
			int index)
{
	ppc64_runlatch_off();
	power7_idle();
	ppc64_runlatch_on();
	return index;
}

/*
 * States for dedicated partition case.
 */
static struct cpuidle_state powernv_states[] = {
	{ /* Snooze */
		.name = "snooze",
		.desc = "snooze",
		.flags = CPUIDLE_FLAG_TIME_VALID,
		.exit_latency = 0,
		.target_residency = 0,
		.enter = &snooze_loop },
	{ /* NAP */
		.name = "NAP",
		.desc = "NAP",
		.flags = CPUIDLE_FLAG_TIME_VALID,
		.exit_latency = 10,
		.target_residency = 100,
		.enter = &nap_loop },
};

static int powernv_cpuidle_add_cpu_notifier(struct notifier_block *n,
			unsigned long action, void *hcpu)
{
	int hotcpu = (unsigned long)hcpu;
	struct cpuidle_device *dev =
				per_cpu(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 setup_hotplug_notifier = {
	.notifier_call = powernv_cpuidle_add_cpu_notifier,
};

/*
 * powernv_cpuidle_driver_init()
 */
static int powernv_cpuidle_driver_init(void)
{
	int idle_state;
	struct cpuidle_driver *drv = &powernv_idle_driver;

	drv->state_count = 0;

	for (idle_state = 0; idle_state < max_idle_state; ++idle_state) {
		/* Is the state not enabled? */
		if (cpuidle_state_table[idle_state].enter == NULL)
			continue;

		drv->states[drv->state_count] =	/* structure copy */
			cpuidle_state_table[idle_state];

		drv->state_count += 1;
	}

	return 0;
}

/*
 * powernv_idle_probe()
 * Choose state table for shared versus dedicated partition
 */
static int powernv_idle_probe(void)
{

	if (cpuidle_disable != IDLE_NO_OVERRIDE)
		return -ENODEV;

	if (firmware_has_feature(FW_FEATURE_OPALv3)) {
		cpuidle_state_table = powernv_states;
		max_idle_state = ARRAY_SIZE(powernv_states);
 	} else
 		return -ENODEV;

	return 0;
}

static int __init powernv_processor_idle_init(void)
{
	int retval;

	retval = powernv_idle_probe();
	if (retval)
		return retval;

	powernv_cpuidle_driver_init();
	retval = cpuidle_register(&powernv_idle_driver, NULL);
	if (retval) {
		printk(KERN_DEBUG "Registration of powernv driver failed.\n");
		return retval;
	}

	register_cpu_notifier(&setup_hotplug_notifier);
	printk(KERN_DEBUG "powernv_idle_driver registered\n");
	return 0;
}

device_initcall(powernv_processor_idle_init);
Commit	Line	Data
2c2e6ecf DD	1	/*
	2	* cpuidle-powernv - idle state cpuidle driver.
	3	* Adapted from drivers/cpuidle/cpuidle-pseries
	4	*
	5	*/
	6
	7	#include <linux/kernel.h>
	8	#include <linux/module.h>
	9	#include <linux/init.h>
	10	#include <linux/moduleparam.h>
	11	#include <linux/cpuidle.h>
	12	#include <linux/cpu.h>
	13	#include <linux/notifier.h>
	14
	15	#include <asm/machdep.h>
	16	#include <asm/firmware.h>
591ac0cb	17	#include <asm/runlatch.h>
2c2e6ecf DD	18
	19	struct cpuidle_driver powernv_idle_driver = {
	20	.name = "powernv_idle",
	21	.owner = THIS_MODULE,
	22	};
	23
	24	static int max_idle_state;
	25	static struct cpuidle_state *cpuidle_state_table;
	26
	27	static int snooze_loop(struct cpuidle_device *dev,
	28	struct cpuidle_driver *drv,
	29	int index)
	30	{
	31	local_irq_enable();
	32	set_thread_flag(TIF_POLLING_NRFLAG);
	33
591ac0cb	34	ppc64_runlatch_off();
2c2e6ecf DD	35	while (!need_resched()) {
	36	HMT_low();
	37	HMT_very_low();
	38	}
	39
	40	HMT_medium();
591ac0cb	41	ppc64_runlatch_on();
2c2e6ecf DD	42	clear_thread_flag(TIF_POLLING_NRFLAG);
	43	smp_mb();
	44	return index;
	45	}
	46
	47	static int nap_loop(struct cpuidle_device *dev,
	48	struct cpuidle_driver *drv,
	49	int index)
	50	{
591ac0cb	51	ppc64_runlatch_off();
2c2e6ecf	52	power7_idle();
591ac0cb	53	ppc64_runlatch_on();
2c2e6ecf DD	54	return index;
	55	}
	56
	57	/*
	58	* States for dedicated partition case.
	59	*/
	60	static struct cpuidle_state powernv_states[] = {
	61	{ /* Snooze */
	62	.name = "snooze",
	63	.desc = "snooze",
	64	.flags = CPUIDLE_FLAG_TIME_VALID,
	65	.exit_latency = 0,
	66	.target_residency = 0,
	67	.enter = &snooze_loop },
	68	{ /* NAP */
	69	.name = "NAP",
	70	.desc = "NAP",
	71	.flags = CPUIDLE_FLAG_TIME_VALID,
	72	.exit_latency = 10,
	73	.target_residency = 100,
	74	.enter = &nap_loop },
	75	};
	76
	77	static int powernv_cpuidle_add_cpu_notifier(struct notifier_block *n,
	78	unsigned long action, void *hcpu)
	79	{
	80	int hotcpu = (unsigned long)hcpu;
	81	struct cpuidle_device *dev =
	82	per_cpu(cpuidle_devices, hotcpu);
	83
	84	if (dev && cpuidle_get_driver()) {
	85	switch (action) {
	86	case CPU_ONLINE:
	87	case CPU_ONLINE_FROZEN:
	88	cpuidle_pause_and_lock();
	89	cpuidle_enable_device(dev);
	90	cpuidle_resume_and_unlock();
	91	break;
	92
	93	case CPU_DEAD:
	94	case CPU_DEAD_FROZEN:
	95	cpuidle_pause_and_lock();
	96	cpuidle_disable_device(dev);
	97	cpuidle_resume_and_unlock();
	98	break;
	99
	100	default:
	101	return NOTIFY_DONE;
	102	}
	103	}
	104	return NOTIFY_OK;
	105	}
	106
	107	static struct notifier_block setup_hotplug_notifier = {
	108	.notifier_call = powernv_cpuidle_add_cpu_notifier,
	109	};
	110
	111	/*
	112	* powernv_cpuidle_driver_init()
	113	*/
	114	static int powernv_cpuidle_driver_init(void)
	115	{
	116	int idle_state;
	117	struct cpuidle_driver *drv = &powernv_idle_driver;
118
119	drv->state_count = 0;
120
121	for (idle_state = 0; idle_state < max_idle_state; ++idle_state) {
122	/* Is the state not enabled? */
123	if (cpuidle_state_table[idle_state].enter == NULL)
124	continue;
125
126	drv->states[drv->state_count] = /* structure copy */
127	cpuidle_state_table[idle_state];
128
129	drv->state_count += 1;
130	}
131
132	return 0;
133	}
134
135	/*
136	* powernv_idle_probe()
137	* Choose state table for shared versus dedicated partition
138	*/
139	static int powernv_idle_probe(void)
140	{
141
142	if (cpuidle_disable != IDLE_NO_OVERRIDE)
143	return -ENODEV;
144
145	if (firmware_has_feature(FW_FEATURE_OPALv3)) {
146	cpuidle_state_table = powernv_states;
147	max_idle_state = ARRAY_SIZE(powernv_states);
148	} else
149	return -ENODEV;
150
151	return 0;
152	}
153
154	static int __init powernv_processor_idle_init(void)
155	{
156	int retval;
157
158	retval = powernv_idle_probe();
159	if (retval)
160	return retval;
161
162	powernv_cpuidle_driver_init();
163	retval = cpuidle_register(&powernv_idle_driver, NULL);
164	if (retval) {
165	printk(KERN_DEBUG "Registration of powernv driver failed.\n");
166	return retval;
167	}
168
169	register_cpu_notifier(&setup_hotplug_notifier);
170	printk(KERN_DEBUG "powernv_idle_driver registered\n");
171	return 0;
172	}
173
174	device_initcall(powernv_processor_idle_init);