[net-next-2.6.git] / drivers / idle / intel_idle.c

/*
 * intel_idle.c - native hardware idle loop for modern Intel processors
 *
 * Copyright (c) 2010, Intel Corporation.
 * Len Brown <len.brown@intel.com>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
 */

/*
 * intel_idle is a cpuidle driver that loads on specific Intel processors
 * in lieu of the legacy ACPI processor_idle driver.  The intent is to
 * make Linux more efficient on these processors, as intel_idle knows
 * more than ACPI, as well as make Linux more immune to ACPI BIOS bugs.
 */

/*
 * Design Assumptions
 *
 * All CPUs have same idle states as boot CPU
 *
 * Chipset BM_STS (bus master status) bit is a NOP
 *	for preventing entry into deep C-stats
 */

/*
 * Known limitations
 *
 * The driver currently initializes for_each_online_cpu() upon modprobe.
 * It it unaware of subsequent processors hot-added to the system.
 * This means that if you boot with maxcpus=n and later online
 * processors above n, those processors will use C1 only.
 *
 * ACPI has a .suspend hack to turn off deep c-statees during suspend
 * to avoid complications with the lapic timer workaround.
 * Have not seen issues with suspend, but may need same workaround here.
 *
 * There is currently no kernel-based automatic probing/loading mechanism
 * if the driver is built as a module.
 */

/* un-comment DEBUG to enable pr_debug() statements */
#define DEBUG

#include <linux/kernel.h>
#include <linux/cpuidle.h>
#include <linux/clockchips.h>
#include <linux/hrtimer.h>	/* ktime_get_real() */
#include <trace/events/power.h>
#include <linux/sched.h>
#include <asm/mwait.h>

#define INTEL_IDLE_VERSION "0.4"
#define PREFIX "intel_idle: "

static struct cpuidle_driver intel_idle_driver = {
	.name = "intel_idle",
	.owner = THIS_MODULE,
};
/* intel_idle.max_cstate=0 disables driver */
static int max_cstate = MWAIT_MAX_NUM_CSTATES - 1;

static unsigned int mwait_substates;

/* Reliable LAPIC Timer States, bit 1 for C1 etc.  */
static unsigned int lapic_timer_reliable_states;

static struct cpuidle_device __percpu *intel_idle_cpuidle_devices;
static int intel_idle(struct cpuidle_device *dev, struct cpuidle_state *state);

static struct cpuidle_state *cpuidle_state_table;

/*
 * States are indexed by the cstate number,
 * which is also the index into the MWAIT hint array.
 * Thus C0 is a dummy.
 */
static struct cpuidle_state nehalem_cstates[MWAIT_MAX_NUM_CSTATES] = {
	{ /* MWAIT C0 */ },
	{ /* MWAIT C1 */
		.name = "NHM-C1",
		.desc = "MWAIT 0x00",
		.driver_data = (void *) 0x00,
		.flags = CPUIDLE_FLAG_TIME_VALID,
		.exit_latency = 3,
		.power_usage = 1000,
		.target_residency = 6,
		.enter = &intel_idle },
	{ /* MWAIT C2 */
		.name = "NHM-C3",
		.desc = "MWAIT 0x10",
		.driver_data = (void *) 0x10,
		.flags = CPUIDLE_FLAG_TIME_VALID | CPUIDLE_FLAG_TLB_FLUSHED,
		.exit_latency = 20,
		.power_usage = 500,
		.target_residency = 80,
		.enter = &intel_idle },
	{ /* MWAIT C3 */
		.name = "NHM-C6",
		.desc = "MWAIT 0x20",
		.driver_data = (void *) 0x20,
		.flags = CPUIDLE_FLAG_TIME_VALID | CPUIDLE_FLAG_TLB_FLUSHED,
		.exit_latency = 200,
		.power_usage = 350,
		.target_residency = 800,
		.enter = &intel_idle },
};

static struct cpuidle_state atom_cstates[MWAIT_MAX_NUM_CSTATES] = {
	{ /* MWAIT C0 */ },
	{ /* MWAIT C1 */
		.name = "ATM-C1",
		.desc = "MWAIT 0x00",
		.driver_data = (void *) 0x00,
		.flags = CPUIDLE_FLAG_TIME_VALID,
		.exit_latency = 1,
		.power_usage = 1000,
		.target_residency = 4,
		.enter = &intel_idle },
	{ /* MWAIT C2 */
		.name = "ATM-C2",
		.desc = "MWAIT 0x10",
		.driver_data = (void *) 0x10,
		.flags = CPUIDLE_FLAG_TIME_VALID,
		.exit_latency = 20,
		.power_usage = 500,
		.target_residency = 80,
		.enter = &intel_idle },
	{ /* MWAIT C3 */ },
	{ /* MWAIT C4 */
		.name = "ATM-C4",
		.desc = "MWAIT 0x30",
		.driver_data = (void *) 0x30,
		.flags = CPUIDLE_FLAG_TIME_VALID | CPUIDLE_FLAG_TLB_FLUSHED,
		.exit_latency = 100,
		.power_usage = 250,
		.target_residency = 400,
		.enter = &intel_idle },
	{ /* MWAIT C5 */ },
	{ /* MWAIT C6 */
		.name = "ATM-C6",
		.desc = "MWAIT 0x52",
		.driver_data = (void *) 0x52,
		.flags = CPUIDLE_FLAG_TIME_VALID | CPUIDLE_FLAG_TLB_FLUSHED,
		.exit_latency = 140,
		.power_usage = 150,
		.target_residency = 560,
		.enter = &intel_idle },
};

/**
 * intel_idle
 * @dev: cpuidle_device
 * @state: cpuidle state
 *
 */
static int intel_idle(struct cpuidle_device *dev, struct cpuidle_state *state)
{
	unsigned long ecx = 1; /* break on interrupt flag */
	unsigned long eax = (unsigned long)cpuidle_get_statedata(state);
	unsigned int cstate;
	ktime_t kt_before, kt_after;
	s64 usec_delta;
	int cpu = smp_processor_id();

	cstate = (((eax) >> MWAIT_SUBSTATE_SIZE) & MWAIT_CSTATE_MASK) + 1;

	local_irq_disable();

	/*
	 * If the state flag indicates that the TLB will be flushed or if this
	 * is the deepest c-state supported, do a voluntary leave mm to avoid
	 * costly and mostly unnecessary wakeups for flushing the user TLB's
	 * associated with the active mm.
	 */
	if (state->flags & CPUIDLE_FLAG_TLB_FLUSHED ||
	    (&dev->states[dev->state_count - 1] == state))
		leave_mm(cpu);

	if (!(lapic_timer_reliable_states & (1 << (cstate))))
		clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER, &cpu);

	kt_before = ktime_get_real();

	stop_critical_timings();
#ifndef MODULE
	trace_power_start(POWER_CSTATE, (eax >> 4) + 1, cpu);
#endif
	if (!need_resched()) {

		__monitor((void *)&current_thread_info()->flags, 0, 0);
		smp_mb();
		if (!need_resched())
			__mwait(eax, ecx);
	}

	start_critical_timings();

	kt_after = ktime_get_real();
	usec_delta = ktime_to_us(ktime_sub(kt_after, kt_before));

	local_irq_enable();

	if (!(lapic_timer_reliable_states & (1 << (cstate))))
		clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_EXIT, &cpu);

	return usec_delta;
}

/*
 * intel_idle_probe()
 */
static int intel_idle_probe(void)
{
	unsigned int eax, ebx, ecx;

	if (max_cstate == 0) {
		pr_debug(PREFIX "disabled\n");
		return -EPERM;
	}

	if (boot_cpu_data.x86_vendor != X86_VENDOR_INTEL)
		return -ENODEV;

	if (!boot_cpu_has(X86_FEATURE_MWAIT))
		return -ENODEV;

	if (boot_cpu_data.cpuid_level < CPUID_MWAIT_LEAF)
		return -ENODEV;

	cpuid(CPUID_MWAIT_LEAF, &eax, &ebx, &ecx, &mwait_substates);

	if (!(ecx & CPUID5_ECX_EXTENSIONS_SUPPORTED) ||
		!(ecx & CPUID5_ECX_INTERRUPT_BREAK))
			return -ENODEV;

	pr_debug(PREFIX "MWAIT substates: 0x%x\n", mwait_substates);

	if (boot_cpu_has(X86_FEATURE_ARAT))	/* Always Reliable APIC Timer */
		lapic_timer_reliable_states = 0xFFFFFFFF;

	if (boot_cpu_data.x86 != 6)	/* family 6 */
		return -ENODEV;

	switch (boot_cpu_data.x86_model) {

	case 0x1A:	/* Core i7, Xeon 5500 series */
	case 0x1E:	/* Core i7 and i5 Processor - Lynnfield Jasper Forest */
	case 0x1F:	/* Core i7 and i5 Processor - Nehalem */
	case 0x2E:	/* Nehalem-EX Xeon */
	case 0x2F:	/* Westmere-EX Xeon */
		lapic_timer_reliable_states = (1 << 1);	 /* C1 */

	case 0x25:	/* Westmere */
	case 0x2C:	/* Westmere */
		cpuidle_state_table = nehalem_cstates;
		break;

	case 0x1C:	/* 28 - Atom Processor */
	case 0x26:	/* 38 - Lincroft Atom Processor */
		lapic_timer_reliable_states = (1 << 2) | (1 << 1); /* C2, C1 */
		cpuidle_state_table = atom_cstates;
		break;
#ifdef FUTURE_USE
	case 0x17:	/* 23 - Core 2 Duo */
		lapic_timer_reliable_states = (1 << 2) | (1 << 1); /* C2, C1 */
#endif

	default:
		pr_debug(PREFIX "does not run on family %d model %d\n",
			boot_cpu_data.x86, boot_cpu_data.x86_model);
		return -ENODEV;
	}

	pr_debug(PREFIX "v" INTEL_IDLE_VERSION
		" model 0x%X\n", boot_cpu_data.x86_model);

	pr_debug(PREFIX "lapic_timer_reliable_states 0x%x\n",
		lapic_timer_reliable_states);
	return 0;
}

/*
 * intel_idle_cpuidle_devices_uninit()
 * unregister, free cpuidle_devices
 */
static void intel_idle_cpuidle_devices_uninit(void)
{
	int i;
	struct cpuidle_device *dev;

	for_each_online_cpu(i) {
		dev = per_cpu_ptr(intel_idle_cpuidle_devices, i);
		cpuidle_unregister_device(dev);
	}

	free_percpu(intel_idle_cpuidle_devices);
	return;
}
/*
 * intel_idle_cpuidle_devices_init()
 * allocate, initialize, register cpuidle_devices
 */
static int intel_idle_cpuidle_devices_init(void)
{
	int i, cstate;
	struct cpuidle_device *dev;

	intel_idle_cpuidle_devices = alloc_percpu(struct cpuidle_device);
	if (intel_idle_cpuidle_devices == NULL)
		return -ENOMEM;

	for_each_online_cpu(i) {
		dev = per_cpu_ptr(intel_idle_cpuidle_devices, i);

		dev->state_count = 1;

		for (cstate = 1; cstate < MWAIT_MAX_NUM_CSTATES; ++cstate) {
			int num_substates;

			if (cstate > max_cstate) {
				printk(PREFIX "max_cstate %d reached\n",
					max_cstate);
				break;
			}

			/* does the state exist in CPUID.MWAIT? */
			num_substates = (mwait_substates >> ((cstate) * 4))
						& MWAIT_SUBSTATE_MASK;
			if (num_substates == 0)
				continue;
			/* is the state not enabled? */
			if (cpuidle_state_table[cstate].enter == NULL) {
				/* does the driver not know about the state? */
				if (*cpuidle_state_table[cstate].name == '\0')
					pr_debug(PREFIX "unaware of model 0x%x"
						" MWAIT %d please"
						" contact lenb@kernel.org",
					boot_cpu_data.x86_model, cstate);
				continue;
			}

			if ((cstate > 2) &&
				!boot_cpu_has(X86_FEATURE_NONSTOP_TSC))
				mark_tsc_unstable("TSC halts in idle"
					" states deeper than C2");

			dev->states[dev->state_count] =	/* structure copy */
				cpuidle_state_table[cstate];

			dev->state_count += 1;
		}

		dev->cpu = i;
		if (cpuidle_register_device(dev)) {
			pr_debug(PREFIX "cpuidle_register_device %d failed!\n",
				 i);
			intel_idle_cpuidle_devices_uninit();
			return -EIO;
		}
	}

	return 0;
}


static int __init intel_idle_init(void)
{
	int retval;

	retval = intel_idle_probe();
	if (retval)
		return retval;

	retval = cpuidle_register_driver(&intel_idle_driver);
	if (retval) {
		printk(KERN_DEBUG PREFIX "intel_idle yielding to %s",
			cpuidle_get_driver()->name);
		return retval;
	}

	retval = intel_idle_cpuidle_devices_init();
	if (retval) {
		cpuidle_unregister_driver(&intel_idle_driver);
		return retval;
	}

	return 0;
}

static void __exit intel_idle_exit(void)
{
	intel_idle_cpuidle_devices_uninit();
	cpuidle_unregister_driver(&intel_idle_driver);

	return;
}

module_init(intel_idle_init);
module_exit(intel_idle_exit);

module_param(max_cstate, int, 0444);

MODULE_AUTHOR("Len Brown <len.brown@intel.com>");
MODULE_DESCRIPTION("Cpuidle driver for Intel Hardware v" INTEL_IDLE_VERSION);
MODULE_LICENSE("GPL");
Commit	Line	Data
26717172 LB	1	/*
	2	* intel_idle.c - native hardware idle loop for modern Intel processors
	3	*
	4	* Copyright (c) 2010, Intel Corporation.
	5	* Len Brown <len.brown@intel.com>
	6	*
	7	* This program is free software; you can redistribute it and/or modify it
	8	* under the terms and conditions of the GNU General Public License,
	9	* version 2, as published by the Free Software Foundation.
	10	*
	11	* This program is distributed in the hope it will be useful, but WITHOUT
	12	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	13	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
	14	* more details.
	15	*
	16	* You should have received a copy of the GNU General Public License along with
	17	* this program; if not, write to the Free Software Foundation, Inc.,
	18	* 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
	19	*/
	20
	21	/*
	22	* intel_idle is a cpuidle driver that loads on specific Intel processors
	23	* in lieu of the legacy ACPI processor_idle driver. The intent is to
	24	* make Linux more efficient on these processors, as intel_idle knows
	25	* more than ACPI, as well as make Linux more immune to ACPI BIOS bugs.
	26	*/
	27
	28	/*
	29	* Design Assumptions
	30	*
	31	* All CPUs have same idle states as boot CPU
	32	*
	33	* Chipset BM_STS (bus master status) bit is a NOP
	34	* for preventing entry into deep C-stats
	35	*/
	36
	37	/*
	38	* Known limitations
	39	*
	40	* The driver currently initializes for_each_online_cpu() upon modprobe.
	41	* It it unaware of subsequent processors hot-added to the system.
	42	* This means that if you boot with maxcpus=n and later online
	43	* processors above n, those processors will use C1 only.
	44	*
	45	* ACPI has a .suspend hack to turn off deep c-statees during suspend
	46	* to avoid complications with the lapic timer workaround.
	47	* Have not seen issues with suspend, but may need same workaround here.
	48	*
	49	* There is currently no kernel-based automatic probing/loading mechanism
	50	* if the driver is built as a module.
	51	*/
	52
	53	/* un-comment DEBUG to enable pr_debug() statements */
	54	#define DEBUG
	55
	56	#include <linux/kernel.h>
	57	#include <linux/cpuidle.h>
	58	#include <linux/clockchips.h>
	59	#include <linux/hrtimer.h> /* ktime_get_real() */
	60	#include <trace/events/power.h>
	61	#include <linux/sched.h>
bc83cccc	62	#include <asm/mwait.h>
26717172 LB	63
	64	#define INTEL_IDLE_VERSION "0.4"
	65	#define PREFIX "intel_idle: "
	66
26717172 LB	67	static struct cpuidle_driver intel_idle_driver = {
	68	.name = "intel_idle",
	69	.owner = THIS_MODULE,
	70	};
	71	/* intel_idle.max_cstate=0 disables driver */
	72	static int max_cstate = MWAIT_MAX_NUM_CSTATES - 1;
26717172	73
c4236282	74	static unsigned int mwait_substates;
26717172 LB	75
	76	/* Reliable LAPIC Timer States, bit 1 for C1 etc. */
	77	static unsigned int lapic_timer_reliable_states;
	78
3265eba0	79	static struct cpuidle_device __percpu *intel_idle_cpuidle_devices;
26717172 LB	80	static int intel_idle(struct cpuidle_device dev, struct cpuidle_state state);
	81
	82	static struct cpuidle_state *cpuidle_state_table;
	83
	84	/*
	85	* States are indexed by the cstate number,
	86	* which is also the index into the MWAIT hint array.
	87	* Thus C0 is a dummy.
	88	*/
	89	static struct cpuidle_state nehalem_cstates[MWAIT_MAX_NUM_CSTATES] = {
	90	{ /* MWAIT C0 */ },
	91	{ /* MWAIT C1 */
	92	.name = "NHM-C1",
	93	.desc = "MWAIT 0x00",
	94	.driver_data = (void *) 0x00,
	95	.flags = CPUIDLE_FLAG_TIME_VALID,
	96	.exit_latency = 3,
	97	.power_usage = 1000,
	98	.target_residency = 6,
	99	.enter = &intel_idle },
	100	{ /* MWAIT C2 */
	101	.name = "NHM-C3",
	102	.desc = "MWAIT 0x10",
	103	.driver_data = (void *) 0x10,
6110a1f4	104	.flags = CPUIDLE_FLAG_TIME_VALID \| CPUIDLE_FLAG_TLB_FLUSHED,
26717172 LB	105	.exit_latency = 20,
	106	.power_usage = 500,
	107	.target_residency = 80,
	108	.enter = &intel_idle },
	109	{ /* MWAIT C3 */
	110	.name = "NHM-C6",
	111	.desc = "MWAIT 0x20",
	112	.driver_data = (void *) 0x20,
6110a1f4	113	.flags = CPUIDLE_FLAG_TIME_VALID \| CPUIDLE_FLAG_TLB_FLUSHED,
26717172 LB	114	.exit_latency = 200,
	115	.power_usage = 350,
	116	.target_residency = 800,
	117	.enter = &intel_idle },
	118	};
	119
	120	static struct cpuidle_state atom_cstates[MWAIT_MAX_NUM_CSTATES] = {
	121	{ /* MWAIT C0 */ },
	122	{ /* MWAIT C1 */
	123	.name = "ATM-C1",
	124	.desc = "MWAIT 0x00",
	125	.driver_data = (void *) 0x00,
	126	.flags = CPUIDLE_FLAG_TIME_VALID,
	127	.exit_latency = 1,
	128	.power_usage = 1000,
	129	.target_residency = 4,
	130	.enter = &intel_idle },
	131	{ /* MWAIT C2 */
	132	.name = "ATM-C2",
	133	.desc = "MWAIT 0x10",
	134	.driver_data = (void *) 0x10,
	135	.flags = CPUIDLE_FLAG_TIME_VALID,
	136	.exit_latency = 20,
	137	.power_usage = 500,
	138	.target_residency = 80,
	139	.enter = &intel_idle },
	140	{ /* MWAIT C3 */ },
	141	{ /* MWAIT C4 */
	142	.name = "ATM-C4",
	143	.desc = "MWAIT 0x30",
	144	.driver_data = (void *) 0x30,
6110a1f4	145	.flags = CPUIDLE_FLAG_TIME_VALID \| CPUIDLE_FLAG_TLB_FLUSHED,
26717172 LB	146	.exit_latency = 100,
	147	.power_usage = 250,
	148	.target_residency = 400,
	149	.enter = &intel_idle },
	150	{ /* MWAIT C5 */ },
	151	{ /* MWAIT C6 */
	152	.name = "ATM-C6",
7fcca7d9 LB	153	.desc = "MWAIT 0x52",
7fcca7d9 LB	154	.driver_data = (void *) 0x52,
6110a1f4	155	.flags = CPUIDLE_FLAG_TIME_VALID \| CPUIDLE_FLAG_TLB_FLUSHED,
7fcca7d9	156	.exit_latency = 140,
26717172	157	.power_usage = 150,
7fcca7d9 LB	158	.target_residency = 560,
7fcca7d9 LB	159	.enter = &intel_idle },
26717172 LB	160	};
26717172 LB	161
26717172 LB	162	/**
	163	* intel_idle
	164	* @dev: cpuidle_device
	165	* @state: cpuidle state
	166	*
	167	*/
	168	static int intel_idle(struct cpuidle_device dev, struct cpuidle_state state)
	169	{
	170	unsigned long ecx = 1; /* break on interrupt flag */
	171	unsigned long eax = (unsigned long)cpuidle_get_statedata(state);
	172	unsigned int cstate;
	173	ktime_t kt_before, kt_after;
	174	s64 usec_delta;
	175	int cpu = smp_processor_id();
	176
	177	cstate = (((eax) >> MWAIT_SUBSTATE_SIZE) & MWAIT_CSTATE_MASK) + 1;
	178
26717172 LB	179	local_irq_disable();
26717172 LB	180
6110a1f4 SS	181	/*
	182	* If the state flag indicates that the TLB will be flushed or if this
	183	* is the deepest c-state supported, do a voluntary leave mm to avoid
	184	* costly and mostly unnecessary wakeups for flushing the user TLB's
	185	* associated with the active mm.
	186	*/
	187	if (state->flags & CPUIDLE_FLAG_TLB_FLUSHED \|\|
	188	(&dev->states[dev->state_count - 1] == state))
	189	leave_mm(cpu);
	190
26717172 LB	191	if (!(lapic_timer_reliable_states & (1 << (cstate))))
	192	clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER, &cpu);
	193
	194	kt_before = ktime_get_real();
	195
	196	stop_critical_timings();
	197	#ifndef MODULE
8d91530c	198	trace_power_start(POWER_CSTATE, (eax >> 4) + 1, cpu);
26717172 LB	199	#endif
	200	if (!need_resched()) {
	201
	202	__monitor((void *)&current_thread_info()->flags, 0, 0);
	203	smp_mb();
	204	if (!need_resched())
	205	__mwait(eax, ecx);
	206	}
	207
	208	start_critical_timings();
	209
	210	kt_after = ktime_get_real();
	211	usec_delta = ktime_to_us(ktime_sub(kt_after, kt_before));
	212
	213	local_irq_enable();
	214
	215	if (!(lapic_timer_reliable_states & (1 << (cstate))))
	216	clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_EXIT, &cpu);
	217
	218	return usec_delta;
	219	}
	220
	221	/*
	222	* intel_idle_probe()
	223	*/
	224	static int intel_idle_probe(void)
	225	{
c4236282	226	unsigned int eax, ebx, ecx;
26717172 LB	227
	228	if (max_cstate == 0) {
	229	pr_debug(PREFIX "disabled\n");
	230	return -EPERM;
	231	}
	232
	233	if (boot_cpu_data.x86_vendor != X86_VENDOR_INTEL)
	234	return -ENODEV;
	235
	236	if (!boot_cpu_has(X86_FEATURE_MWAIT))
	237	return -ENODEV;
	238
	239	if (boot_cpu_data.cpuid_level < CPUID_MWAIT_LEAF)
	240	return -ENODEV;
	241
c4236282	242	cpuid(CPUID_MWAIT_LEAF, &eax, &ebx, &ecx, &mwait_substates);
26717172 LB	243
	244	if (!(ecx & CPUID5_ECX_EXTENSIONS_SUPPORTED) \|\|
	245	!(ecx & CPUID5_ECX_INTERRUPT_BREAK))
	246	return -ENODEV;
26717172	247
c4236282	248	pr_debug(PREFIX "MWAIT substates: 0x%x\n", mwait_substates);
26717172 LB	249
	250	if (boot_cpu_has(X86_FEATURE_ARAT)) /* Always Reliable APIC Timer */
	251	lapic_timer_reliable_states = 0xFFFFFFFF;
	252
	253	if (boot_cpu_data.x86 != 6) /* family 6 */
	254	return -ENODEV;
	255
	256	switch (boot_cpu_data.x86_model) {
	257
	258	case 0x1A: /* Core i7, Xeon 5500 series */
	259	case 0x1E: /* Core i7 and i5 Processor - Lynnfield Jasper Forest */
	260	case 0x1F: /* Core i7 and i5 Processor - Nehalem */
	261	case 0x2E: /* Nehalem-EX Xeon */
ec67a2ba	262	case 0x2F: /* Westmere-EX Xeon */
26717172 LB	263	lapic_timer_reliable_states = (1 << 1); /* C1 */
	264
	265	case 0x25: /* Westmere */
	266	case 0x2C: /* Westmere */
	267	cpuidle_state_table = nehalem_cstates;
26717172 LB	268	break;
	269
	270	case 0x1C: /* 28 - Atom Processor */
4725fd3c	271	case 0x26: /* 38 - Lincroft Atom Processor */
26717172 LB	272	lapic_timer_reliable_states = (1 << 2) \| (1 << 1); /* C2, C1 */
26717172 LB	273	cpuidle_state_table = atom_cstates;
26717172 LB	274	break;
	275	#ifdef FUTURE_USE
	276	case 0x17: /* 23 - Core 2 Duo */
	277	lapic_timer_reliable_states = (1 << 2) \| (1 << 1); /* C2, C1 */
	278	#endif
	279
	280	default:
	281	pr_debug(PREFIX "does not run on family %d model %d\n",
	282	boot_cpu_data.x86, boot_cpu_data.x86_model);
	283	return -ENODEV;
	284	}
	285
	286	pr_debug(PREFIX "v" INTEL_IDLE_VERSION
	287	" model 0x%X\n", boot_cpu_data.x86_model);
	288
	289	pr_debug(PREFIX "lapic_timer_reliable_states 0x%x\n",
	290	lapic_timer_reliable_states);
	291	return 0;
	292	}
	293
	294	/*
	295	* intel_idle_cpuidle_devices_uninit()
	296	* unregister, free cpuidle_devices
	297	*/
	298	static void intel_idle_cpuidle_devices_uninit(void)
	299	{
	300	int i;
	301	struct cpuidle_device *dev;
	302
	303	for_each_online_cpu(i) {
	304	dev = per_cpu_ptr(intel_idle_cpuidle_devices, i);
	305	cpuidle_unregister_device(dev);
	306	}
	307
	308	free_percpu(intel_idle_cpuidle_devices);
	309	return;
	310	}
	311	/*
	312	* intel_idle_cpuidle_devices_init()
	313	* allocate, initialize, register cpuidle_devices
	314	*/
	315	static int intel_idle_cpuidle_devices_init(void)
	316	{
	317	int i, cstate;
	318	struct cpuidle_device *dev;
	319
	320	intel_idle_cpuidle_devices = alloc_percpu(struct cpuidle_device);
	321	if (intel_idle_cpuidle_devices == NULL)
	322	return -ENOMEM;
	323
	324	for_each_online_cpu(i) {
	325	dev = per_cpu_ptr(intel_idle_cpuidle_devices, i);
	326
	327	dev->state_count = 1;
	328
	329	for (cstate = 1; cstate < MWAIT_MAX_NUM_CSTATES; ++cstate) {
	330	int num_substates;
	331
	332	if (cstate > max_cstate) {
	333	printk(PREFIX "max_cstate %d reached\n",
	334	max_cstate);
	335	break;
	336	}
	337
338	/* does the state exist in CPUID.MWAIT? */
c4236282	339	num_substates = (mwait_substates >> ((cstate) * 4))
26717172 LB	340	& MWAIT_SUBSTATE_MASK;
	341	if (num_substates == 0)
	342	continue;
	343	/* is the state not enabled? */
	344	if (cpuidle_state_table[cstate].enter == NULL) {
	345	/* does the driver not know about the state? */
	346	if (*cpuidle_state_table[cstate].name == '\0')
	347	pr_debug(PREFIX "unaware of model 0x%x"
	348	" MWAIT %d please"
	349	" contact lenb@kernel.org",
	350	boot_cpu_data.x86_model, cstate);
	351	continue;
	352	}
	353
	354	if ((cstate > 2) &&
	355	!boot_cpu_has(X86_FEATURE_NONSTOP_TSC))
	356	mark_tsc_unstable("TSC halts in idle"
	357	" states deeper than C2");
	358
	359	dev->states[dev->state_count] = /* structure copy */
	360	cpuidle_state_table[cstate];
	361
	362	dev->state_count += 1;
	363	}
	364
	365	dev->cpu = i;
	366	if (cpuidle_register_device(dev)) {
	367	pr_debug(PREFIX "cpuidle_register_device %d failed!\n",
	368	i);
	369	intel_idle_cpuidle_devices_uninit();
	370	return -EIO;
	371	}
	372	}
	373
	374	return 0;
	375	}
	376
	377
	378	static int __init intel_idle_init(void)
	379	{
	380	int retval;
	381
	382	retval = intel_idle_probe();
	383	if (retval)
	384	return retval;
	385
	386	retval = cpuidle_register_driver(&intel_idle_driver);
	387	if (retval) {
	388	printk(KERN_DEBUG PREFIX "intel_idle yielding to %s",
	389	cpuidle_get_driver()->name);
	390	return retval;
	391	}
	392
	393	retval = intel_idle_cpuidle_devices_init();
	394	if (retval) {
	395	cpuidle_unregister_driver(&intel_idle_driver);
	396	return retval;
	397	}
	398
	399	return 0;
	400	}
	401
	402	static void __exit intel_idle_exit(void)
	403	{
404	intel_idle_cpuidle_devices_uninit();
405	cpuidle_unregister_driver(&intel_idle_driver);
406
407	return;
408	}
409
410	module_init(intel_idle_init);
411	module_exit(intel_idle_exit);
412
26717172	413	module_param(max_cstate, int, 0444);
26717172 LB	414
	415	MODULE_AUTHOR("Len Brown <len.brown@intel.com>");
	416	MODULE_DESCRIPTION("Cpuidle driver for Intel Hardware v" INTEL_IDLE_VERSION);
	417	MODULE_LICENSE("GPL");