[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;
	/* 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 & 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 =
					((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 & 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 =
					((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>
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;
9b6a68d9 MN	76	/* Do not exit powersave upon decrementer as we've setup the timer
9b6a68d9 MN	77	* offload.
0d948730	78	*/
9b6a68d9	79	new_lpcr &= ~LPCR_PECE1;
0d948730 PM	80
	81	mtspr(SPRN_LPCR, new_lpcr);
	82	power7_sleep();
	83
	84	mtspr(SPRN_LPCR, old_lpcr);
	85
	86	return index;
	87	}
	88
2c2e6ecf DD	89	/*
	90	* States for dedicated partition case.
	91	*/
0888839c	92	static struct cpuidle_state powernv_states[MAX_POWERNV_IDLE_STATES] = {
2c2e6ecf DD	93	{ /* Snooze */
	94	.name = "snooze",
	95	.desc = "snooze",
	96	.flags = CPUIDLE_FLAG_TIME_VALID,
	97	.exit_latency = 0,
	98	.target_residency = 0,
	99	.enter = &snooze_loop },
2c2e6ecf DD	100	};
	101
	102	static int powernv_cpuidle_add_cpu_notifier(struct notifier_block *n,
	103	unsigned long action, void *hcpu)
	104	{
	105	int hotcpu = (unsigned long)hcpu;
	106	struct cpuidle_device *dev =
	107	per_cpu(cpuidle_devices, hotcpu);
	108
	109	if (dev && cpuidle_get_driver()) {
	110	switch (action) {
	111	case CPU_ONLINE:
	112	case CPU_ONLINE_FROZEN:
	113	cpuidle_pause_and_lock();
	114	cpuidle_enable_device(dev);
	115	cpuidle_resume_and_unlock();
	116	break;
	117
	118	case CPU_DEAD:
	119	case CPU_DEAD_FROZEN:
	120	cpuidle_pause_and_lock();
	121	cpuidle_disable_device(dev);
	122	cpuidle_resume_and_unlock();
	123	break;
	124
	125	default:
	126	return NOTIFY_DONE;
	127	}
	128	}
	129	return NOTIFY_OK;
	130	}
	131
	132	static struct notifier_block setup_hotplug_notifier = {
	133	.notifier_call = powernv_cpuidle_add_cpu_notifier,
	134	};
	135
	136	/*
	137	* powernv_cpuidle_driver_init()
	138	*/
	139	static int powernv_cpuidle_driver_init(void)
	140	{
	141	int idle_state;
	142	struct cpuidle_driver *drv = &powernv_idle_driver;
	143
	144	drv->state_count = 0;
	145
	146	for (idle_state = 0; idle_state < max_idle_state; ++idle_state) {
	147	/* Is the state not enabled? */
	148	if (cpuidle_state_table[idle_state].enter == NULL)
	149	continue;
	150
	151	drv->states[drv->state_count] = /* structure copy */
	152	cpuidle_state_table[idle_state];
	153
	154	drv->state_count += 1;
	155	}
	156
	157	return 0;
	158	}
	159
0888839c PM	160	static int powernv_add_idle_states(void)
	161	{
	162	struct device_node *power_mgt;
0888839c PM	163	int nr_idle_states = 1; /* Snooze */
0888839c PM	164	int dt_idle_states;
95707d85	165	const __be32 *idle_state_flags;
74aa51b5 PM	166	const __be32 *idle_state_latency;
74aa51b5 PM	167	u32 len_flags, flags, latency_ns;
0888839c PM	168	int i;
	169
	170	/* Currently we have snooze statically defined */
	171
	172	power_mgt = of_find_node_by_path("/ibm,opal/power-mgt");
	173	if (!power_mgt) {
	174	pr_warn("opal: PowerMgmt Node not found\n");
	175	return nr_idle_states;
	176	}
	177
95707d85 VS	178	idle_state_flags = of_get_property(power_mgt, "ibm,cpu-idle-state-flags", &len_flags);
95707d85 VS	179	if (!idle_state_flags) {
0888839c PM	180	pr_warn("DT-PowerMgmt: missing ibm,cpu-idle-state-flags\n");
	181	return nr_idle_states;
	182	}
	183
74aa51b5 PM	184	idle_state_latency = of_get_property(power_mgt,
	185	"ibm,cpu-idle-state-latencies-ns", NULL);
	186	if (!idle_state_latency) {
	187	pr_warn("DT-PowerMgmt: missing ibm,cpu-idle-state-latencies-ns\n");
	188	return nr_idle_states;
	189	}
	190
95707d85	191	dt_idle_states = len_flags / sizeof(u32);
0888839c PM	192
	193	for (i = 0; i < dt_idle_states; i++) {
	194
95707d85	195	flags = be32_to_cpu(idle_state_flags[i]);
74aa51b5 PM	196
	197	/* Cpuidle accepts exit_latency in us and we estimate
	198	* target residency to be 10x exit_latency
	199	*/
	200	latency_ns = be32_to_cpu(idle_state_latency[i]);
95707d85	201	if (flags & IDLE_USE_INST_NAP) {
0888839c PM	202	/* Add NAP state */
	203	strcpy(powernv_states[nr_idle_states].name, "Nap");
	204	strcpy(powernv_states[nr_idle_states].desc, "Nap");
	205	powernv_states[nr_idle_states].flags = CPUIDLE_FLAG_TIME_VALID;
74aa51b5 PM	206	powernv_states[nr_idle_states].exit_latency =
	207	((unsigned int)latency_ns) / 1000;
	208	powernv_states[nr_idle_states].target_residency =
	209	((unsigned int)latency_ns / 100);
0888839c PM	210	powernv_states[nr_idle_states].enter = &nap_loop;
	211	nr_idle_states++;
	212	}
	213
95707d85	214	if (flags & IDLE_USE_INST_SLEEP) {
0888839c PM	215	/* Add FASTSLEEP state */
	216	strcpy(powernv_states[nr_idle_states].name, "FastSleep");
	217	strcpy(powernv_states[nr_idle_states].desc, "FastSleep");
	218	powernv_states[nr_idle_states].flags =
	219	CPUIDLE_FLAG_TIME_VALID \| CPUIDLE_FLAG_TIMER_STOP;
74aa51b5 PM	220	powernv_states[nr_idle_states].exit_latency =
	221	((unsigned int)latency_ns) / 1000;
	222	powernv_states[nr_idle_states].target_residency =
	223	((unsigned int)latency_ns / 100);
0888839c PM	224	powernv_states[nr_idle_states].enter = &fastsleep_loop;
	225	nr_idle_states++;
	226	}
	227	}
	228
	229	return nr_idle_states;
	230	}
	231
2c2e6ecf DD	232	/*
	233	* powernv_idle_probe()
	234	* Choose state table for shared versus dedicated partition
	235	*/
	236	static int powernv_idle_probe(void)
	237	{
2c2e6ecf DD	238	if (cpuidle_disable != IDLE_NO_OVERRIDE)
	239	return -ENODEV;
	240
	241	if (firmware_has_feature(FW_FEATURE_OPALv3)) {
	242	cpuidle_state_table = powernv_states;
0888839c PM	243	/* Device tree can indicate more idle states */
0888839c PM	244	max_idle_state = powernv_add_idle_states();
2c2e6ecf DD	245	} else
	246	return -ENODEV;
	247
	248	return 0;
	249	}
	250
	251	static int __init powernv_processor_idle_init(void)
	252	{
	253	int retval;
	254
	255	retval = powernv_idle_probe();
	256	if (retval)
	257	return retval;
	258
	259	powernv_cpuidle_driver_init();
	260	retval = cpuidle_register(&powernv_idle_driver, NULL);
	261	if (retval) {
	262	printk(KERN_DEBUG "Registration of powernv driver failed.\n");
	263	return retval;
	264	}
	265
	266	register_cpu_notifier(&setup_hotplug_notifier);
	267	printk(KERN_DEBUG "powernv_idle_driver registered\n");
	268	return 0;
	269	}
	270
	271	device_initcall(powernv_processor_idle_init);