[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/runlatch.h>

/* Flags and constants used in PowerNV platform */

#define MAX_POWERNV_IDLE_STATES	8
#define IDLE_USE_INST_NAP	0x00010000 /* Use nap instruction */
#define IDLE_USE_INST_SLEEP	0x00020000 /* Use sleep instruction */

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;
	new_lpcr &= ~(LPCR_MER | LPCR_PECE); /* lpcr[mer] must be 0 */

	/* exit powersave upon external interrupt, but not decrementer
	 * interrupt.
	 */
	new_lpcr |= LPCR_PECE0;

	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;
	struct property *prop;
	int nr_idle_states = 1; /* Snooze */
	int dt_idle_states;
	u32 *flags;
	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;
	}

	prop = of_find_property(power_mgt, "ibm,cpu-idle-state-flags", NULL);
	if (!prop) {
		pr_warn("DT-PowerMgmt: missing ibm,cpu-idle-state-flags\n");
		return nr_idle_states;
	}

	dt_idle_states = prop->length / sizeof(u32);
	flags = (u32 *) prop->value;

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

		if (flags[i] & IDLE_USE_INST_NAP) {
			/* 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 = 10;
			powernv_states[nr_idle_states].target_residency = 100;
			powernv_states[nr_idle_states].enter = &nap_loop;
			nr_idle_states++;
		}

		if (flags[i] & IDLE_USE_INST_SLEEP) {
			/* 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 = 300;
			powernv_states[nr_idle_states].target_residency = 1000000;
			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>
591ac0cb	19	#include <asm/runlatch.h>
2c2e6ecf	20
0888839c PM	21	/* Flags and constants used in PowerNV platform */
	22
	23	#define MAX_POWERNV_IDLE_STATES 8
	24	#define IDLE_USE_INST_NAP 0x00010000 /* Use nap instruction */
	25	#define IDLE_USE_INST_SLEEP 0x00020000 /* Use sleep instruction */
	26
2c2e6ecf DD	27	struct cpuidle_driver powernv_idle_driver = {
	28	.name = "powernv_idle",
	29	.owner = THIS_MODULE,
	30	};
	31
	32	static int max_idle_state;
	33	static struct cpuidle_state *cpuidle_state_table;
	34
	35	static int snooze_loop(struct cpuidle_device *dev,
	36	struct cpuidle_driver *drv,
	37	int index)
	38	{
	39	local_irq_enable();
	40	set_thread_flag(TIF_POLLING_NRFLAG);
	41
591ac0cb	42	ppc64_runlatch_off();
2c2e6ecf DD	43	while (!need_resched()) {
	44	HMT_low();
	45	HMT_very_low();
	46	}
	47
	48	HMT_medium();
591ac0cb	49	ppc64_runlatch_on();
2c2e6ecf DD	50	clear_thread_flag(TIF_POLLING_NRFLAG);
	51	smp_mb();
	52	return index;
	53	}
	54
	55	static int nap_loop(struct cpuidle_device *dev,
	56	struct cpuidle_driver *drv,
	57	int index)
	58	{
591ac0cb	59	ppc64_runlatch_off();
2c2e6ecf	60	power7_idle();
591ac0cb	61	ppc64_runlatch_on();
2c2e6ecf DD	62	return index;
	63	}
	64
0d948730 PM	65	static int fastsleep_loop(struct cpuidle_device *dev,
	66	struct cpuidle_driver *drv,
	67	int index)
	68	{
	69	unsigned long old_lpcr = mfspr(SPRN_LPCR);
	70	unsigned long new_lpcr;
	71
	72	if (unlikely(system_state < SYSTEM_RUNNING))
	73	return index;
	74
	75	new_lpcr = old_lpcr;
	76	new_lpcr &= ~(LPCR_MER \| LPCR_PECE); /* lpcr[mer] must be 0 */
	77
	78	/* exit powersave upon external interrupt, but not decrementer
	79	* interrupt.
	80	*/
	81	new_lpcr \|= LPCR_PECE0;
	82
	83	mtspr(SPRN_LPCR, new_lpcr);
	84	power7_sleep();
	85
	86	mtspr(SPRN_LPCR, old_lpcr);
	87
	88	return index;
	89	}
	90
2c2e6ecf DD	91	/*
	92	* States for dedicated partition case.
	93	*/
0888839c	94	static struct cpuidle_state powernv_states[MAX_POWERNV_IDLE_STATES] = {
2c2e6ecf DD	95	{ /* Snooze */
	96	.name = "snooze",
	97	.desc = "snooze",
	98	.flags = CPUIDLE_FLAG_TIME_VALID,
	99	.exit_latency = 0,
	100	.target_residency = 0,
	101	.enter = &snooze_loop },
2c2e6ecf DD	102	};
	103
	104	static int powernv_cpuidle_add_cpu_notifier(struct notifier_block *n,
	105	unsigned long action, void *hcpu)
	106	{
	107	int hotcpu = (unsigned long)hcpu;
	108	struct cpuidle_device *dev =
	109	per_cpu(cpuidle_devices, hotcpu);
	110
	111	if (dev && cpuidle_get_driver()) {
	112	switch (action) {
	113	case CPU_ONLINE:
	114	case CPU_ONLINE_FROZEN:
	115	cpuidle_pause_and_lock();
	116	cpuidle_enable_device(dev);
	117	cpuidle_resume_and_unlock();
	118	break;
	119
	120	case CPU_DEAD:
	121	case CPU_DEAD_FROZEN:
	122	cpuidle_pause_and_lock();
	123	cpuidle_disable_device(dev);
	124	cpuidle_resume_and_unlock();
	125	break;
	126
	127	default:
	128	return NOTIFY_DONE;
	129	}
	130	}
	131	return NOTIFY_OK;
	132	}
	133
	134	static struct notifier_block setup_hotplug_notifier = {
	135	.notifier_call = powernv_cpuidle_add_cpu_notifier,
	136	};
	137
	138	/*
	139	* powernv_cpuidle_driver_init()
	140	*/
	141	static int powernv_cpuidle_driver_init(void)
	142	{
	143	int idle_state;
	144	struct cpuidle_driver *drv = &powernv_idle_driver;
	145
	146	drv->state_count = 0;
	147
	148	for (idle_state = 0; idle_state < max_idle_state; ++idle_state) {
	149	/* Is the state not enabled? */
	150	if (cpuidle_state_table[idle_state].enter == NULL)
	151	continue;
	152
	153	drv->states[drv->state_count] = /* structure copy */
	154	cpuidle_state_table[idle_state];
	155
	156	drv->state_count += 1;
	157	}
	158
	159	return 0;
	160	}
	161
0888839c PM	162	static int powernv_add_idle_states(void)
	163	{
	164	struct device_node *power_mgt;
	165	struct property *prop;
	166	int nr_idle_states = 1; /* Snooze */
	167	int dt_idle_states;
	168	u32 *flags;
	169	int i;
	170
	171	/* Currently we have snooze statically defined */
	172
	173	power_mgt = of_find_node_by_path("/ibm,opal/power-mgt");
	174	if (!power_mgt) {
	175	pr_warn("opal: PowerMgmt Node not found\n");
	176	return nr_idle_states;
	177	}
	178
	179	prop = of_find_property(power_mgt, "ibm,cpu-idle-state-flags", NULL);
	180	if (!prop) {
	181	pr_warn("DT-PowerMgmt: missing ibm,cpu-idle-state-flags\n");
	182	return nr_idle_states;
	183	}
	184
	185	dt_idle_states = prop->length / sizeof(u32);
	186	flags = (u32 *) prop->value;
	187
	188	for (i = 0; i < dt_idle_states; i++) {
	189
	190	if (flags[i] & IDLE_USE_INST_NAP) {
	191	/* Add NAP state */
	192	strcpy(powernv_states[nr_idle_states].name, "Nap");
	193	strcpy(powernv_states[nr_idle_states].desc, "Nap");
	194	powernv_states[nr_idle_states].flags = CPUIDLE_FLAG_TIME_VALID;
	195	powernv_states[nr_idle_states].exit_latency = 10;
	196	powernv_states[nr_idle_states].target_residency = 100;
	197	powernv_states[nr_idle_states].enter = &nap_loop;
	198	nr_idle_states++;
	199	}
	200
	201	if (flags[i] & IDLE_USE_INST_SLEEP) {
	202	/* Add FASTSLEEP state */
	203	strcpy(powernv_states[nr_idle_states].name, "FastSleep");
	204	strcpy(powernv_states[nr_idle_states].desc, "FastSleep");
	205	powernv_states[nr_idle_states].flags =
	206	CPUIDLE_FLAG_TIME_VALID \| CPUIDLE_FLAG_TIMER_STOP;
	207	powernv_states[nr_idle_states].exit_latency = 300;
	208	powernv_states[nr_idle_states].target_residency = 1000000;
	209	powernv_states[nr_idle_states].enter = &fastsleep_loop;
	210	nr_idle_states++;
	211	}
	212	}
	213
	214	return nr_idle_states;
	215	}
	216
2c2e6ecf DD	217	/*
	218	* powernv_idle_probe()
	219	* Choose state table for shared versus dedicated partition
	220	*/
	221	static int powernv_idle_probe(void)
	222	{
2c2e6ecf DD	223	if (cpuidle_disable != IDLE_NO_OVERRIDE)
	224	return -ENODEV;
	225
	226	if (firmware_has_feature(FW_FEATURE_OPALv3)) {
	227	cpuidle_state_table = powernv_states;
0888839c PM	228	/* Device tree can indicate more idle states */
0888839c PM	229	max_idle_state = powernv_add_idle_states();
2c2e6ecf DD	230	} else
	231	return -ENODEV;
	232
	233	return 0;
	234	}
	235
	236	static int __init powernv_processor_idle_init(void)
	237	{
	238	int retval;
	239
	240	retval = powernv_idle_probe();
	241	if (retval)
	242	return retval;
	243
	244	powernv_cpuidle_driver_init();
	245	retval = cpuidle_register(&powernv_idle_driver, NULL);
	246	if (retval) {
	247	printk(KERN_DEBUG "Registration of powernv driver failed.\n");
	248	return retval;
	249	}
	250
	251	register_cpu_notifier(&setup_hotplug_notifier);
	252	printk(KERN_DEBUG "powernv_idle_driver registered\n");
	253	return 0;
	254	}
	255
	256	device_initcall(powernv_processor_idle_init);