[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 <linux/clockchips.h>
#include <linux/of.h>

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

#define MAX_POWERNV_IDLE_STATES	8

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;
}

static int fastsleep_loop(struct cpuidle_device *dev,
				struct cpuidle_driver *drv,
				int index)
{
	unsigned long old_lpcr = mfspr(SPRN_LPCR);
	unsigned long new_lpcr;

	if (unlikely(system_state < SYSTEM_RUNNING))
		return index;

	new_lpcr = old_lpcr;
	/* Do not exit powersave upon decrementer as we've setup the timer
	 * offload.
	 */
	new_lpcr &= ~LPCR_PECE1;

	mtspr(SPRN_LPCR, new_lpcr);
	power7_sleep();

	mtspr(SPRN_LPCR, old_lpcr);

	return index;
}

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

static int powernv_add_idle_states(void)
{
	struct device_node *power_mgt;
	int nr_idle_states = 1; /* Snooze */
	int dt_idle_states;
	const __be32 *idle_state_flags;
	const __be32 *idle_state_latency;
	u32 len_flags, flags, latency_ns;
	int i;

	/* Currently we have snooze statically defined */

	power_mgt = of_find_node_by_path("/ibm,opal/power-mgt");
	if (!power_mgt) {
		pr_warn("opal: PowerMgmt Node not found\n");
		return nr_idle_states;
	}

	idle_state_flags = of_get_property(power_mgt, "ibm,cpu-idle-state-flags", &len_flags);
	if (!idle_state_flags) {
		pr_warn("DT-PowerMgmt: missing ibm,cpu-idle-state-flags\n");
		return nr_idle_states;
	}

	idle_state_latency = of_get_property(power_mgt,
			"ibm,cpu-idle-state-latencies-ns", NULL);
	if (!idle_state_latency) {
		pr_warn("DT-PowerMgmt: missing ibm,cpu-idle-state-latencies-ns\n");
		return nr_idle_states;
	}

	dt_idle_states = len_flags / sizeof(u32);

	for (i = 0; i < dt_idle_states; i++) {

		flags = be32_to_cpu(idle_state_flags[i]);

		/* Cpuidle accepts exit_latency in us and we estimate
		 * target residency to be 10x exit_latency
		 */
		latency_ns = be32_to_cpu(idle_state_latency[i]);
		if (flags & OPAL_PM_NAP_ENABLED) {
			/* Add NAP state */
			strcpy(powernv_states[nr_idle_states].name, "Nap");
			strcpy(powernv_states[nr_idle_states].desc, "Nap");
			powernv_states[nr_idle_states].flags = CPUIDLE_FLAG_TIME_VALID;
			powernv_states[nr_idle_states].exit_latency =
					((unsigned int)latency_ns) / 1000;
			powernv_states[nr_idle_states].target_residency =
					((unsigned int)latency_ns / 100);
			powernv_states[nr_idle_states].enter = &nap_loop;
			nr_idle_states++;
		}

		if (flags & OPAL_PM_SLEEP_ENABLED) {
			/* Add FASTSLEEP state */
			strcpy(powernv_states[nr_idle_states].name, "FastSleep");
			strcpy(powernv_states[nr_idle_states].desc, "FastSleep");
			powernv_states[nr_idle_states].flags =
				CPUIDLE_FLAG_TIME_VALID | CPUIDLE_FLAG_TIMER_STOP;
			powernv_states[nr_idle_states].exit_latency =
					((unsigned int)latency_ns) / 1000;
			powernv_states[nr_idle_states].target_residency =
					((unsigned int)latency_ns / 100);
			powernv_states[nr_idle_states].enter = &fastsleep_loop;
			nr_idle_states++;
		}
	}

	return nr_idle_states;
}

/*
 * 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;
		/* Device tree can indicate more idle states */
		max_idle_state = powernv_add_idle_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>
0d948730	14	#include <linux/clockchips.h>
0888839c	15	#include <linux/of.h>
2c2e6ecf DD	16
	17	#include <asm/machdep.h>
	18	#include <asm/firmware.h>
8eb8ac89	19	#include <asm/opal.h>
591ac0cb	20	#include <asm/runlatch.h>
2c2e6ecf	21
0888839c	22	#define MAX_POWERNV_IDLE_STATES 8
0888839c	23
2c2e6ecf DD	24	struct cpuidle_driver powernv_idle_driver = {
	25	.name = "powernv_idle",
	26	.owner = THIS_MODULE,
	27	};
	28
	29	static int max_idle_state;
	30	static struct cpuidle_state *cpuidle_state_table;
	31
	32	static int snooze_loop(struct cpuidle_device *dev,
	33	struct cpuidle_driver *drv,
	34	int index)
	35	{
	36	local_irq_enable();
	37	set_thread_flag(TIF_POLLING_NRFLAG);
	38
591ac0cb	39	ppc64_runlatch_off();
2c2e6ecf DD	40	while (!need_resched()) {
	41	HMT_low();
	42	HMT_very_low();
	43	}
	44
	45	HMT_medium();
591ac0cb	46	ppc64_runlatch_on();
2c2e6ecf DD	47	clear_thread_flag(TIF_POLLING_NRFLAG);
	48	smp_mb();
	49	return index;
	50	}
	51
	52	static int nap_loop(struct cpuidle_device *dev,
	53	struct cpuidle_driver *drv,
	54	int index)
	55	{
591ac0cb	56	ppc64_runlatch_off();
2c2e6ecf	57	power7_idle();
591ac0cb	58	ppc64_runlatch_on();
2c2e6ecf DD	59	return index;
	60	}
	61
0d948730 PM	62	static int fastsleep_loop(struct cpuidle_device *dev,
	63	struct cpuidle_driver *drv,
	64	int index)
	65	{
	66	unsigned long old_lpcr = mfspr(SPRN_LPCR);
	67	unsigned long new_lpcr;
	68
	69	if (unlikely(system_state < SYSTEM_RUNNING))
	70	return index;
	71
	72	new_lpcr = old_lpcr;
9b6a68d9 MN	73	/* Do not exit powersave upon decrementer as we've setup the timer
9b6a68d9 MN	74	* offload.
0d948730	75	*/
9b6a68d9	76	new_lpcr &= ~LPCR_PECE1;
0d948730 PM	77
	78	mtspr(SPRN_LPCR, new_lpcr);
	79	power7_sleep();
	80
	81	mtspr(SPRN_LPCR, old_lpcr);
	82
	83	return index;
	84	}
	85
2c2e6ecf DD	86	/*
	87	* States for dedicated partition case.
	88	*/
0888839c	89	static struct cpuidle_state powernv_states[MAX_POWERNV_IDLE_STATES] = {
2c2e6ecf DD	90	{ /* Snooze */
	91	.name = "snooze",
	92	.desc = "snooze",
	93	.flags = CPUIDLE_FLAG_TIME_VALID,
	94	.exit_latency = 0,
	95	.target_residency = 0,
	96	.enter = &snooze_loop },
2c2e6ecf DD	97	};
	98
	99	static int powernv_cpuidle_add_cpu_notifier(struct notifier_block *n,
	100	unsigned long action, void *hcpu)
	101	{
	102	int hotcpu = (unsigned long)hcpu;
	103	struct cpuidle_device *dev =
	104	per_cpu(cpuidle_devices, hotcpu);
	105
	106	if (dev && cpuidle_get_driver()) {
	107	switch (action) {
	108	case CPU_ONLINE:
	109	case CPU_ONLINE_FROZEN:
	110	cpuidle_pause_and_lock();
	111	cpuidle_enable_device(dev);
	112	cpuidle_resume_and_unlock();
	113	break;
	114
	115	case CPU_DEAD:
	116	case CPU_DEAD_FROZEN:
	117	cpuidle_pause_and_lock();
	118	cpuidle_disable_device(dev);
	119	cpuidle_resume_and_unlock();
	120	break;
	121
	122	default:
	123	return NOTIFY_DONE;
	124	}
	125	}
	126	return NOTIFY_OK;
	127	}
	128
	129	static struct notifier_block setup_hotplug_notifier = {
	130	.notifier_call = powernv_cpuidle_add_cpu_notifier,
	131	};
	132
	133	/*
	134	* powernv_cpuidle_driver_init()
	135	*/
	136	static int powernv_cpuidle_driver_init(void)
	137	{
	138	int idle_state;
	139	struct cpuidle_driver *drv = &powernv_idle_driver;
	140
	141	drv->state_count = 0;
	142
	143	for (idle_state = 0; idle_state < max_idle_state; ++idle_state) {
	144	/* Is the state not enabled? */
	145	if (cpuidle_state_table[idle_state].enter == NULL)
	146	continue;
	147
	148	drv->states[drv->state_count] = /* structure copy */
	149	cpuidle_state_table[idle_state];
	150
	151	drv->state_count += 1;
	152	}
	153
	154	return 0;
	155	}
	156
0888839c PM	157	static int powernv_add_idle_states(void)
	158	{
	159	struct device_node *power_mgt;
0888839c PM	160	int nr_idle_states = 1; /* Snooze */
0888839c PM	161	int dt_idle_states;
95707d85	162	const __be32 *idle_state_flags;
74aa51b5 PM	163	const __be32 *idle_state_latency;
74aa51b5 PM	164	u32 len_flags, flags, latency_ns;
0888839c PM	165	int i;
	166
	167	/* Currently we have snooze statically defined */
	168
	169	power_mgt = of_find_node_by_path("/ibm,opal/power-mgt");
	170	if (!power_mgt) {
	171	pr_warn("opal: PowerMgmt Node not found\n");
	172	return nr_idle_states;
	173	}
	174
95707d85 VS	175	idle_state_flags = of_get_property(power_mgt, "ibm,cpu-idle-state-flags", &len_flags);
95707d85 VS	176	if (!idle_state_flags) {
0888839c PM	177	pr_warn("DT-PowerMgmt: missing ibm,cpu-idle-state-flags\n");
	178	return nr_idle_states;
	179	}
	180
74aa51b5 PM	181	idle_state_latency = of_get_property(power_mgt,
	182	"ibm,cpu-idle-state-latencies-ns", NULL);
	183	if (!idle_state_latency) {
	184	pr_warn("DT-PowerMgmt: missing ibm,cpu-idle-state-latencies-ns\n");
	185	return nr_idle_states;
	186	}
	187
95707d85	188	dt_idle_states = len_flags / sizeof(u32);
0888839c PM	189
	190	for (i = 0; i < dt_idle_states; i++) {
	191
95707d85	192	flags = be32_to_cpu(idle_state_flags[i]);
74aa51b5 PM	193
	194	/* Cpuidle accepts exit_latency in us and we estimate
	195	* target residency to be 10x exit_latency
	196	*/
	197	latency_ns = be32_to_cpu(idle_state_latency[i]);
8eb8ac89	198	if (flags & OPAL_PM_NAP_ENABLED) {
0888839c PM	199	/* Add NAP state */
	200	strcpy(powernv_states[nr_idle_states].name, "Nap");
	201	strcpy(powernv_states[nr_idle_states].desc, "Nap");
	202	powernv_states[nr_idle_states].flags = CPUIDLE_FLAG_TIME_VALID;
74aa51b5 PM	203	powernv_states[nr_idle_states].exit_latency =
	204	((unsigned int)latency_ns) / 1000;
	205	powernv_states[nr_idle_states].target_residency =
	206	((unsigned int)latency_ns / 100);
0888839c PM	207	powernv_states[nr_idle_states].enter = &nap_loop;
	208	nr_idle_states++;
	209	}
	210
8eb8ac89	211	if (flags & OPAL_PM_SLEEP_ENABLED) {
0888839c PM	212	/* Add FASTSLEEP state */
	213	strcpy(powernv_states[nr_idle_states].name, "FastSleep");
	214	strcpy(powernv_states[nr_idle_states].desc, "FastSleep");
	215	powernv_states[nr_idle_states].flags =
	216	CPUIDLE_FLAG_TIME_VALID \| CPUIDLE_FLAG_TIMER_STOP;
74aa51b5 PM	217	powernv_states[nr_idle_states].exit_latency =
	218	((unsigned int)latency_ns) / 1000;
	219	powernv_states[nr_idle_states].target_residency =
	220	((unsigned int)latency_ns / 100);
0888839c PM	221	powernv_states[nr_idle_states].enter = &fastsleep_loop;
	222	nr_idle_states++;
	223	}
	224	}
	225
	226	return nr_idle_states;
	227	}
	228
2c2e6ecf DD	229	/*
	230	* powernv_idle_probe()
	231	* Choose state table for shared versus dedicated partition
	232	*/
	233	static int powernv_idle_probe(void)
	234	{
2c2e6ecf DD	235	if (cpuidle_disable != IDLE_NO_OVERRIDE)
	236	return -ENODEV;
	237
	238	if (firmware_has_feature(FW_FEATURE_OPALv3)) {
	239	cpuidle_state_table = powernv_states;
0888839c PM	240	/* Device tree can indicate more idle states */
0888839c PM	241	max_idle_state = powernv_add_idle_states();
2c2e6ecf DD	242	} else
	243	return -ENODEV;
	244
	245	return 0;
	246	}
	247
	248	static int __init powernv_processor_idle_init(void)
	249	{
	250	int retval;
	251
	252	retval = powernv_idle_probe();
	253	if (retval)
	254	return retval;
	255
	256	powernv_cpuidle_driver_init();
	257	retval = cpuidle_register(&powernv_idle_driver, NULL);
	258	if (retval) {
	259	printk(KERN_DEBUG "Registration of powernv driver failed.\n");
	260	return retval;
	261	}
	262
	263	register_cpu_notifier(&setup_hotplug_notifier);
	264	printk(KERN_DEBUG "powernv_idle_driver registered\n");
	265	return 0;
	266	}
	267
	268	device_initcall(powernv_processor_idle_init);