[deliverable/linux.git] / drivers / cpufreq / speedstep-smi.c

/*
 * Intel SpeedStep SMI driver.
 *
 * (C) 2003  Hiroshi Miura <miura@da-cha.org>
 *
 *  Licensed under the terms of the GNU GPL License version 2.
 *
 */


/*********************************************************************
 *                        SPEEDSTEP - DEFINITIONS                    *
 *********************************************************************/

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/init.h>
#include <linux/cpufreq.h>
#include <linux/delay.h>
#include <linux/io.h>
#include <asm/ist.h>
#include <asm/cpu_device_id.h>

#include "speedstep-lib.h"

/* speedstep system management interface port/command.
 *
 * These parameters are got from IST-SMI BIOS call.
 * If user gives it, these are used.
 *
 */
static int smi_port;
static int smi_cmd;
static unsigned int smi_sig;

/* info about the processor */
static enum speedstep_processor speedstep_processor;

/*
 * There are only two frequency states for each processor. Values
 * are in kHz for the time being.
 */
static struct cpufreq_frequency_table speedstep_freqs[] = {
	{SPEEDSTEP_HIGH,	0},
	{SPEEDSTEP_LOW,		0},
	{0,			CPUFREQ_TABLE_END},
};

#define GET_SPEEDSTEP_OWNER 0
#define GET_SPEEDSTEP_STATE 1
#define SET_SPEEDSTEP_STATE 2
#define GET_SPEEDSTEP_FREQS 4

/* how often shall the SMI call be tried if it failed, e.g. because
 * of DMA activity going on? */
#define SMI_TRIES 5

/**
 * speedstep_smi_ownership
 */
static int speedstep_smi_ownership(void)
{
	u32 command, result, magic, dummy;
	u32 function = GET_SPEEDSTEP_OWNER;
	unsigned char magic_data[] = "Copyright (c) 1999 Intel Corporation";

	command = (smi_sig & 0xffffff00) | (smi_cmd & 0xff);
	magic = virt_to_phys(magic_data);

	pr_debug("trying to obtain ownership with command %x at port %x\n",
			command, smi_port);

	__asm__ __volatile__(
		"push %%ebp\n"
		"out %%al, (%%dx)\n"
		"pop %%ebp\n"
		: "=D" (result),
		  "=a" (dummy), "=b" (dummy), "=c" (dummy), "=d" (dummy),
		  "=S" (dummy)
		: "a" (command), "b" (function), "c" (0), "d" (smi_port),
		  "D" (0), "S" (magic)
		: "memory"
	);

	pr_debug("result is %x\n", result);

	return result;
}

/**
 * speedstep_smi_get_freqs - get SpeedStep preferred & current freq.
 * @low: the low frequency value is placed here
 * @high: the high frequency value is placed here
 *
 * Only available on later SpeedStep-enabled systems, returns false results or
 * even hangs [cf. bugme.osdl.org # 1422] on earlier systems. Empirical testing
 * shows that the latter occurs if !(ist_info.event & 0xFFFF).
 */
static int speedstep_smi_get_freqs(unsigned int *low, unsigned int *high)
{
	u32 command, result = 0, edi, high_mhz, low_mhz, dummy;
	u32 state = 0;
	u32 function = GET_SPEEDSTEP_FREQS;

	if (!(ist_info.event & 0xFFFF)) {
		pr_debug("bug #1422 -- can't read freqs from BIOS\n");
		return -ENODEV;
	}

	command = (smi_sig & 0xffffff00) | (smi_cmd & 0xff);

	pr_debug("trying to determine frequencies with command %x at port %x\n",
			command, smi_port);

	__asm__ __volatile__(
		"push %%ebp\n"
		"out %%al, (%%dx)\n"
		"pop %%ebp"
		: "=a" (result),
		  "=b" (high_mhz),
		  "=c" (low_mhz),
		  "=d" (state), "=D" (edi), "=S" (dummy)
		: "a" (command),
		  "b" (function),
		  "c" (state),
		  "d" (smi_port), "S" (0), "D" (0)
	);

	pr_debug("result %x, low_freq %u, high_freq %u\n",
			result, low_mhz, high_mhz);

	/* abort if results are obviously incorrect... */
	if ((high_mhz + low_mhz) < 600)
		return -EINVAL;

	*high = high_mhz * 1000;
	*low  = low_mhz  * 1000;

	return result;
}

/**
 * speedstep_get_state - set the SpeedStep state
 * @state: processor frequency state (SPEEDSTEP_LOW or SPEEDSTEP_HIGH)
 *
 */
static int speedstep_get_state(void)
{
	u32 function = GET_SPEEDSTEP_STATE;
	u32 result, state, edi, command, dummy;

	command = (smi_sig & 0xffffff00) | (smi_cmd & 0xff);

	pr_debug("trying to determine current setting with command %x "
		"at port %x\n", command, smi_port);

	__asm__ __volatile__(
		"push %%ebp\n"
		"out %%al, (%%dx)\n"
		"pop %%ebp\n"
		: "=a" (result),
		  "=b" (state), "=D" (edi),
		  "=c" (dummy), "=d" (dummy), "=S" (dummy)
		: "a" (command), "b" (function), "c" (0),
		  "d" (smi_port), "S" (0), "D" (0)
	);

	pr_debug("state is %x, result is %x\n", state, result);

	return state & 1;
}


/**
 * speedstep_set_state - set the SpeedStep state
 * @state: new processor frequency state (SPEEDSTEP_LOW or SPEEDSTEP_HIGH)
 *
 */
static void speedstep_set_state(unsigned int state)
{
	unsigned int result = 0, command, new_state, dummy;
	unsigned long flags;
	unsigned int function = SET_SPEEDSTEP_STATE;
	unsigned int retry = 0;

	if (state > 0x1)
		return;

	/* Disable IRQs */
	local_irq_save(flags);

	command = (smi_sig & 0xffffff00) | (smi_cmd & 0xff);

	pr_debug("trying to set frequency to state %u "
		"with command %x at port %x\n",
		state, command, smi_port);

	do {
		if (retry) {
			pr_debug("retry %u, previous result %u, waiting...\n",
					retry, result);
			mdelay(retry * 50);
		}
		retry++;
		__asm__ __volatile__(
			"push %%ebp\n"
			"out %%al, (%%dx)\n"
			"pop %%ebp"
			: "=b" (new_state), "=D" (result),
			  "=c" (dummy), "=a" (dummy),
			  "=d" (dummy), "=S" (dummy)
			: "a" (command), "b" (function), "c" (state),
			  "d" (smi_port), "S" (0), "D" (0)
			);
	} while ((new_state != state) && (retry <= SMI_TRIES));

	/* enable IRQs */
	local_irq_restore(flags);

	if (new_state == state)
		pr_debug("change to %u MHz succeeded after %u tries "
			"with result %u\n",
			(speedstep_freqs[new_state].frequency / 1000),
			retry, result);
	else
		printk(KERN_ERR "cpufreq: change to state %u "
			"failed with new_state %u and result %u\n",
			state, new_state, result);

	return;
}


/**
 * speedstep_target - set a new CPUFreq policy
 * @policy: new policy
 * @target_freq: new freq
 * @relation:
 *
 * Sets a new CPUFreq policy/freq.
 */
static int speedstep_target(struct cpufreq_policy *policy,
			unsigned int target_freq, unsigned int relation)
{
	unsigned int newstate = 0;
	struct cpufreq_freqs freqs;

	if (cpufreq_frequency_table_target(policy, &speedstep_freqs[0],
				target_freq, relation, &newstate))
		return -EINVAL;

	freqs.old = speedstep_freqs[speedstep_get_state()].frequency;
	freqs.new = speedstep_freqs[newstate].frequency;
	freqs.cpu = 0; /* speedstep.c is UP only driver */

	if (freqs.old == freqs.new)
		return 0;

	cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
	speedstep_set_state(newstate);
	cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);

	return 0;
}


/**
 * speedstep_verify - verifies a new CPUFreq policy
 * @policy: new policy
 *
 * Limit must be within speedstep_low_freq and speedstep_high_freq, with
 * at least one border included.
 */
static int speedstep_verify(struct cpufreq_policy *policy)
{
	return cpufreq_frequency_table_verify(policy, &speedstep_freqs[0]);
}


static int speedstep_cpu_init(struct cpufreq_policy *policy)
{
	int result;
	unsigned int speed, state;
	unsigned int *low, *high;

	/* capability check */
	if (policy->cpu != 0)
		return -ENODEV;

	result = speedstep_smi_ownership();
	if (result) {
		pr_debug("fails in acquiring ownership of a SMI interface.\n");
		return -EINVAL;
	}

	/* detect low and high frequency */
	low = &speedstep_freqs[SPEEDSTEP_LOW].frequency;
	high = &speedstep_freqs[SPEEDSTEP_HIGH].frequency;

	result = speedstep_smi_get_freqs(low, high);
	if (result) {
		/* fall back to speedstep_lib.c dection mechanism:
		 * try both states out */
		pr_debug("could not detect low and high frequencies "
				"by SMI call.\n");
		result = speedstep_get_freqs(speedstep_processor,
				low, high,
				NULL,
				&speedstep_set_state);

		if (result) {
			pr_debug("could not detect two different speeds"
					" -- aborting.\n");
			return result;
		} else
			pr_debug("workaround worked.\n");
	}

	/* get current speed setting */
	state = speedstep_get_state();
	speed = speedstep_freqs[state].frequency;

	pr_debug("currently at %s speed setting - %i MHz\n",
		(speed == speedstep_freqs[SPEEDSTEP_LOW].frequency)
		? "low" : "high",
		(speed / 1000));

	/* cpuinfo and default policy values */
	policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
	policy->cur = speed;

	result = cpufreq_frequency_table_cpuinfo(policy, speedstep_freqs);
	if (result)
		return result;

	cpufreq_frequency_table_get_attr(speedstep_freqs, policy->cpu);

	return 0;
}

static int speedstep_cpu_exit(struct cpufreq_policy *policy)
{
	cpufreq_frequency_table_put_attr(policy->cpu);
	return 0;
}

static unsigned int speedstep_get(unsigned int cpu)
{
	if (cpu)
		return -ENODEV;
	return speedstep_get_frequency(speedstep_processor);
}


static int speedstep_resume(struct cpufreq_policy *policy)
{
	int result = speedstep_smi_ownership();

	if (result)
		pr_debug("fails in re-acquiring ownership of a SMI interface.\n");

	return result;
}

static struct freq_attr *speedstep_attr[] = {
	&cpufreq_freq_attr_scaling_available_freqs,
	NULL,
};

static struct cpufreq_driver speedstep_driver = {
	.name		= "speedstep-smi",
	.verify		= speedstep_verify,
	.target		= speedstep_target,
	.init		= speedstep_cpu_init,
	.exit		= speedstep_cpu_exit,
	.get		= speedstep_get,
	.resume		= speedstep_resume,
	.owner		= THIS_MODULE,
	.attr		= speedstep_attr,
};

static const struct x86_cpu_id ss_smi_ids[] = {
	{ X86_VENDOR_INTEL, 6, 0xb, },
	{ X86_VENDOR_INTEL, 6, 0x8, },
	{ X86_VENDOR_INTEL, 15, 2 },
	{}
};
#if 0
/* Not auto loaded currently */
MODULE_DEVICE_TABLE(x86cpu, ss_smi_ids);
#endif

/**
 * speedstep_init - initializes the SpeedStep CPUFreq driver
 *
 *   Initializes the SpeedStep support. Returns -ENODEV on unsupported
 * BIOS, -EINVAL on problems during initiatization, and zero on
 * success.
 */
static int __init speedstep_init(void)
{
	if (!x86_match_cpu(ss_smi_ids))
		return -ENODEV;

	speedstep_processor = speedstep_detect_processor();

	switch (speedstep_processor) {
	case SPEEDSTEP_CPU_PIII_T:
	case SPEEDSTEP_CPU_PIII_C:
	case SPEEDSTEP_CPU_PIII_C_EARLY:
		break;
	default:
		speedstep_processor = 0;
	}

	if (!speedstep_processor) {
		pr_debug("No supported Intel CPU detected.\n");
		return -ENODEV;
	}

	pr_debug("signature:0x%.8ulx, command:0x%.8ulx, "
		"event:0x%.8ulx, perf_level:0x%.8ulx.\n",
		ist_info.signature, ist_info.command,
		ist_info.event, ist_info.perf_level);

	/* Error if no IST-SMI BIOS or no PARM
		 sig= 'ISGE' aka 'Intel Speedstep Gate E' */
	if ((ist_info.signature !=  0x47534943) && (
	    (smi_port == 0) || (smi_cmd == 0)))
		return -ENODEV;

	if (smi_sig == 1)
		smi_sig = 0x47534943;
	else
		smi_sig = ist_info.signature;

	/* setup smi_port from MODLULE_PARM or BIOS */
	if ((smi_port > 0xff) || (smi_port < 0))
		return -EINVAL;
	else if (smi_port == 0)
		smi_port = ist_info.command & 0xff;

	if ((smi_cmd > 0xff) || (smi_cmd < 0))
		return -EINVAL;
	else if (smi_cmd == 0)
		smi_cmd = (ist_info.command >> 16) & 0xff;

	return cpufreq_register_driver(&speedstep_driver);
}


/**
 * speedstep_exit - unregisters SpeedStep support
 *
 *   Unregisters SpeedStep support.
 */
static void __exit speedstep_exit(void)
{
	cpufreq_unregister_driver(&speedstep_driver);
}

module_param(smi_port, int, 0444);
module_param(smi_cmd,  int, 0444);
module_param(smi_sig, uint, 0444);

MODULE_PARM_DESC(smi_port, "Override the BIOS-given IST port with this value "
		"-- Intel's default setting is 0xb2");
MODULE_PARM_DESC(smi_cmd, "Override the BIOS-given IST command with this value "
		"-- Intel's default setting is 0x82");
MODULE_PARM_DESC(smi_sig, "Set to 1 to fake the IST signature when using the "
		"SMI interface.");

MODULE_AUTHOR("Hiroshi Miura");
MODULE_DESCRIPTION("Speedstep driver for IST applet SMI interface.");
MODULE_LICENSE("GPL");

module_init(speedstep_init);
module_exit(speedstep_exit);
Commit	Line	Data
1da177e4 LT	1	/*
	2	* Intel SpeedStep SMI driver.
	3	*
	4	* (C) 2003 Hiroshi Miura <miura@da-cha.org>
	5	*
	6	* Licensed under the terms of the GNU GPL License version 2.
	7	*
	8	*/
	9
	10
	11	/*********************************************************************
	12	* SPEEDSTEP - DEFINITIONS *
	13	*********************************************************************/
	14
	15	#include <linux/kernel.h>
32ee8c3e DJ	16	#include <linux/module.h>
32ee8c3e DJ	17	#include <linux/moduleparam.h>
1da177e4 LT	18	#include <linux/init.h>
1da177e4 LT	19	#include <linux/cpufreq.h>
1da177e4	20	#include <linux/delay.h>
bbfebd66	21	#include <linux/io.h>
1da177e4	22	#include <asm/ist.h>
fa8031ae	23	#include <asm/cpu_device_id.h>
1da177e4 LT	24
	25	#include "speedstep-lib.h"
	26
	27	/* speedstep system management interface port/command.
	28	*
	29	* These parameters are got from IST-SMI BIOS call.
	30	* If user gives it, these are used.
32ee8c3e	31	*
1da177e4	32	*/
bbfebd66 DJ	33	static int smi_port;
	34	static int smi_cmd;
	35	static unsigned int smi_sig;
1da177e4 LT	36
1da177e4 LT	37	/* info about the processor */
1cce76c2	38	static enum speedstep_processor speedstep_processor;
1da177e4	39
32ee8c3e DJ	40	/*
32ee8c3e DJ	41	* There are only two frequency states for each processor. Values
1da177e4 LT	42	* are in kHz for the time being.
	43	*/
	44	static struct cpufreq_frequency_table speedstep_freqs[] = {
32ee8c3e	45	{SPEEDSTEP_HIGH, 0},
1da177e4 LT	46	{SPEEDSTEP_LOW, 0},
	47	{0, CPUFREQ_TABLE_END},
	48	};
	49
	50	#define GET_SPEEDSTEP_OWNER 0
	51	#define GET_SPEEDSTEP_STATE 1
	52	#define SET_SPEEDSTEP_STATE 2
	53	#define GET_SPEEDSTEP_FREQS 4
	54
	55	/* how often shall the SMI call be tried if it failed, e.g. because
	56	* of DMA activity going on? */
	57	#define SMI_TRIES 5
	58
1da177e4 LT	59	/**
	60	* speedstep_smi_ownership
	61	*/
bbfebd66	62	static int speedstep_smi_ownership(void)
1da177e4	63	{
c6e8256a	64	u32 command, result, magic, dummy;
1da177e4 LT	65	u32 function = GET_SPEEDSTEP_OWNER;
	66	unsigned char magic_data[] = "Copyright (c) 1999 Intel Corporation";
	67
	68	command = (smi_sig & 0xffffff00) \| (smi_cmd & 0xff);
	69	magic = virt_to_phys(magic_data);
	70
2d06d8c4	71	pr_debug("trying to obtain ownership with command %x at port %x\n",
bbfebd66	72	command, smi_port);
1da177e4 LT	73
1da177e4 LT	74	__asm__ __volatile__(
c6e8256a	75	"push %%ebp\n"
1da177e4	76	"out %%al, (%%dx)\n"
c6e8256a	77	"pop %%ebp\n"
bbfebd66 DJ	78	: "=D" (result),
	79	"=a" (dummy), "=b" (dummy), "=c" (dummy), "=d" (dummy),
	80	"=S" (dummy)
f081a529	81	: "a" (command), "b" (function), "c" (0), "d" (smi_port),
bbfebd66	82	"D" (0), "S" (magic)
f081a529	83	: "memory"
1da177e4 LT	84	);
1da177e4 LT	85
2d06d8c4	86	pr_debug("result is %x\n", result);
1da177e4 LT	87
	88	return result;
	89	}
	90
	91	/**
	92	* speedstep_smi_get_freqs - get SpeedStep preferred & current freq.
	93	* @low: the low frequency value is placed here
	94	* @high: the high frequency value is placed here
	95	*
	96	* Only available on later SpeedStep-enabled systems, returns false results or
	97	* even hangs [cf. bugme.osdl.org # 1422] on earlier systems. Empirical testing
	98	* shows that the latter occurs if !(ist_info.event & 0xFFFF).
	99	*/
bbfebd66	100	static int speedstep_smi_get_freqs(unsigned int low, unsigned int high)
1da177e4	101	{
c6e8256a	102	u32 command, result = 0, edi, high_mhz, low_mhz, dummy;
bbfebd66	103	u32 state = 0;
1da177e4 LT	104	u32 function = GET_SPEEDSTEP_FREQS;
	105
	106	if (!(ist_info.event & 0xFFFF)) {
2d06d8c4	107	pr_debug("bug #1422 -- can't read freqs from BIOS\n");
1da177e4 LT	108	return -ENODEV;
	109	}
	110
	111	command = (smi_sig & 0xffffff00) \| (smi_cmd & 0xff);
	112
2d06d8c4	113	pr_debug("trying to determine frequencies with command %x at port %x\n",
bbfebd66	114	command, smi_port);
1da177e4	115
c6e8256a SD	116	__asm__ __volatile__(
c6e8256a SD	117	"push %%ebp\n"
1da177e4	118	"out %%al, (%%dx)\n"
c6e8256a	119	"pop %%ebp"
bbfebd66 DJ	120	: "=a" (result),
	121	"=b" (high_mhz),
	122	"=c" (low_mhz),
	123	"=d" (state), "=D" (edi), "=S" (dummy)
	124	: "a" (command),
	125	"b" (function),
	126	"c" (state),
	127	"d" (smi_port), "S" (0), "D" (0)
1da177e4 LT	128	);
1da177e4 LT	129
2d06d8c4	130	pr_debug("result %x, low_freq %u, high_freq %u\n",
bbfebd66	131	result, low_mhz, high_mhz);
1da177e4 LT	132
	133	/* abort if results are obviously incorrect... */
	134	if ((high_mhz + low_mhz) < 600)
	135	return -EINVAL;
	136
	137	high = high_mhz 1000;
	138	low = low_mhz 1000;
	139
	140	return result;
32ee8c3e	141	}
1da177e4 LT	142
	143	/**
	144	* speedstep_get_state - set the SpeedStep state
	145	* @state: processor frequency state (SPEEDSTEP_LOW or SPEEDSTEP_HIGH)
	146	*
	147	*/
bbfebd66	148	static int speedstep_get_state(void)
1da177e4	149	{
bbfebd66	150	u32 function = GET_SPEEDSTEP_STATE;
c6e8256a	151	u32 result, state, edi, command, dummy;
1da177e4 LT	152
	153	command = (smi_sig & 0xffffff00) \| (smi_cmd & 0xff);
	154
2d06d8c4	155	pr_debug("trying to determine current setting with command %x "
bbfebd66	156	"at port %x\n", command, smi_port);
1da177e4	157
c6e8256a SD	158	__asm__ __volatile__(
c6e8256a SD	159	"push %%ebp\n"
1da177e4	160	"out %%al, (%%dx)\n"
c6e8256a	161	"pop %%ebp\n"
bbfebd66 DJ	162	: "=a" (result),
	163	"=b" (state), "=D" (edi),
	164	"=c" (dummy), "=d" (dummy), "=S" (dummy)
	165	: "a" (command), "b" (function), "c" (0),
	166	"d" (smi_port), "S" (0), "D" (0)
1da177e4 LT	167	);
1da177e4 LT	168
2d06d8c4	169	pr_debug("state is %x, result is %x\n", state, result);
1da177e4	170
bbfebd66	171	return state & 1;
1da177e4 LT	172	}
	173
	174
	175	/**
	176	* speedstep_set_state - set the SpeedStep state
	177	* @state: new processor frequency state (SPEEDSTEP_LOW or SPEEDSTEP_HIGH)
	178	*
	179	*/
bbfebd66	180	static void speedstep_set_state(unsigned int state)
1da177e4	181	{
c6e8256a	182	unsigned int result = 0, command, new_state, dummy;
1da177e4	183	unsigned long flags;
bbfebd66	184	unsigned int function = SET_SPEEDSTEP_STATE;
1da177e4 LT	185	unsigned int retry = 0;
	186
	187	if (state > 0x1)
	188	return;
	189
	190	/* Disable IRQs */
	191	local_irq_save(flags);
	192
	193	command = (smi_sig & 0xffffff00) \| (smi_cmd & 0xff);
	194
2d06d8c4	195	pr_debug("trying to set frequency to state %u "
bbfebd66 DJ	196	"with command %x at port %x\n",
bbfebd66 DJ	197	state, command, smi_port);
1da177e4 LT	198
	199	do {
	200	if (retry) {
2d06d8c4	201	pr_debug("retry %u, previous result %u, waiting...\n",
bbfebd66	202	retry, result);
1da177e4 LT	203	mdelay(retry * 50);
	204	}
	205	retry++;
	206	__asm__ __volatile__(
c6e8256a	207	"push %%ebp\n"
1da177e4	208	"out %%al, (%%dx)\n"
c6e8256a	209	"pop %%ebp"
bbfebd66 DJ	210	: "=b" (new_state), "=D" (result),
	211	"=c" (dummy), "=a" (dummy),
	212	"=d" (dummy), "=S" (dummy)
	213	: "a" (command), "b" (function), "c" (state),
	214	"d" (smi_port), "S" (0), "D" (0)
1da177e4 LT	215	);
	216	} while ((new_state != state) && (retry <= SMI_TRIES));
	217
	218	/* enable IRQs */
	219	local_irq_restore(flags);
	220
bbfebd66	221	if (new_state == state)
2d06d8c4	222	pr_debug("change to %u MHz succeeded after %u tries "
bbfebd66 DJ	223	"with result %u\n",
	224	(speedstep_freqs[new_state].frequency / 1000),
	225	retry, result);
	226	else
	227	printk(KERN_ERR "cpufreq: change to state %u "
	228	"failed with new_state %u and result %u\n",
	229	state, new_state, result);
1da177e4 LT	230
	231	return;
	232	}
	233
	234
	235	/**
	236	* speedstep_target - set a new CPUFreq policy
	237	* @policy: new policy
	238	* @target_freq: new freq
32ee8c3e	239	* @relation:
1da177e4 LT	240	*
	241	* Sets a new CPUFreq policy/freq.
	242	*/
bbfebd66	243	static int speedstep_target(struct cpufreq_policy *policy,
1da177e4 LT	244	unsigned int target_freq, unsigned int relation)
	245	{
	246	unsigned int newstate = 0;
	247	struct cpufreq_freqs freqs;
	248
bbfebd66 DJ	249	if (cpufreq_frequency_table_target(policy, &speedstep_freqs[0],
bbfebd66 DJ	250	target_freq, relation, &newstate))
1da177e4 LT	251	return -EINVAL;
	252
	253	freqs.old = speedstep_freqs[speedstep_get_state()].frequency;
	254	freqs.new = speedstep_freqs[newstate].frequency;
	255	freqs.cpu = 0; /* speedstep.c is UP only driver */
	256
	257	if (freqs.old == freqs.new)
	258	return 0;
	259
	260	cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
	261	speedstep_set_state(newstate);
	262	cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
	263
	264	return 0;
	265	}
	266
	267
	268	/**
	269	* speedstep_verify - verifies a new CPUFreq policy
	270	* @policy: new policy
	271	*
	272	* Limit must be within speedstep_low_freq and speedstep_high_freq, with
	273	* at least one border included.
	274	*/
bbfebd66	275	static int speedstep_verify(struct cpufreq_policy *policy)
1da177e4 LT	276	{
	277	return cpufreq_frequency_table_verify(policy, &speedstep_freqs[0]);
	278	}
	279
	280
	281	static int speedstep_cpu_init(struct cpufreq_policy *policy)
	282	{
	283	int result;
bbfebd66 DJ	284	unsigned int speed, state;
bbfebd66 DJ	285	unsigned int low, high;
1da177e4 LT	286
	287	/* capability check */
	288	if (policy->cpu != 0)
	289	return -ENODEV;
	290
	291	result = speedstep_smi_ownership();
	292	if (result) {
2d06d8c4	293	pr_debug("fails in acquiring ownership of a SMI interface.\n");
1da177e4 LT	294	return -EINVAL;
	295	}
	296
	297	/* detect low and high frequency */
bbfebd66 DJ	298	low = &speedstep_freqs[SPEEDSTEP_LOW].frequency;
	299	high = &speedstep_freqs[SPEEDSTEP_HIGH].frequency;
	300
	301	result = speedstep_smi_get_freqs(low, high);
1da177e4	302	if (result) {
bbfebd66 DJ	303	/* fall back to speedstep_lib.c dection mechanism:
bbfebd66 DJ	304	* try both states out */
2d06d8c4	305	pr_debug("could not detect low and high frequencies "
bbfebd66	306	"by SMI call.\n");
1da177e4	307	result = speedstep_get_freqs(speedstep_processor,
bbfebd66	308	low, high,
1a10760c	309	NULL,
1da177e4 LT	310	&speedstep_set_state);
	311
	312	if (result) {
2d06d8c4	313	pr_debug("could not detect two different speeds"
bbfebd66	314	" -- aborting.\n");
1da177e4 LT	315	return result;
1da177e4 LT	316	} else
2d06d8c4	317	pr_debug("workaround worked.\n");
1da177e4 LT	318	}
	319
	320	/* get current speed setting */
	321	state = speedstep_get_state();
	322	speed = speedstep_freqs[state].frequency;
	323
2d06d8c4	324	pr_debug("currently at %s speed setting - %i MHz\n",
bbfebd66 DJ	325	(speed == speedstep_freqs[SPEEDSTEP_LOW].frequency)
bbfebd66 DJ	326	? "low" : "high",
1da177e4 LT	327	(speed / 1000));
	328
	329	/* cpuinfo and default policy values */
1da177e4 LT	330	policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
	331	policy->cur = speed;
	332
	333	result = cpufreq_frequency_table_cpuinfo(policy, speedstep_freqs);
	334	if (result)
bbfebd66	335	return result;
1da177e4	336
32ee8c3e	337	cpufreq_frequency_table_get_attr(speedstep_freqs, policy->cpu);
1da177e4 LT	338
	339	return 0;
	340	}
	341
	342	static int speedstep_cpu_exit(struct cpufreq_policy *policy)
	343	{
	344	cpufreq_frequency_table_put_attr(policy->cpu);
	345	return 0;
	346	}
	347
	348	static unsigned int speedstep_get(unsigned int cpu)
	349	{
	350	if (cpu)
	351	return -ENODEV;
bbfebd66	352	return speedstep_get_frequency(speedstep_processor);
1da177e4 LT	353	}
	354
	355
	356	static int speedstep_resume(struct cpufreq_policy *policy)
	357	{
	358	int result = speedstep_smi_ownership();
	359
	360	if (result)
2d06d8c4	361	pr_debug("fails in re-acquiring ownership of a SMI interface.\n");
1da177e4 LT	362
	363	return result;
	364	}
	365
bbfebd66	366	static struct freq_attr *speedstep_attr[] = {
1da177e4 LT	367	&cpufreq_freq_attr_scaling_available_freqs,
	368	NULL,
	369	};
	370
221dee28	371	static struct cpufreq_driver speedstep_driver = {
1da177e4	372	.name = "speedstep-smi",
32ee8c3e DJ	373	.verify = speedstep_verify,
32ee8c3e DJ	374	.target = speedstep_target,
1da177e4 LT	375	.init = speedstep_cpu_init,
	376	.exit = speedstep_cpu_exit,
	377	.get = speedstep_get,
	378	.resume = speedstep_resume,
	379	.owner = THIS_MODULE,
	380	.attr = speedstep_attr,
	381	};
	382
fa8031ae AK	383	static const struct x86_cpu_id ss_smi_ids[] = {
	384	{ X86_VENDOR_INTEL, 6, 0xb, },
	385	{ X86_VENDOR_INTEL, 6, 0x8, },
	386	{ X86_VENDOR_INTEL, 15, 2 },
	387	{}
	388	};
	389	#if 0
	390	/* Not auto loaded currently */
	391	MODULE_DEVICE_TABLE(x86cpu, ss_smi_ids);
	392	#endif
	393
1da177e4 LT	394	/**
	395	* speedstep_init - initializes the SpeedStep CPUFreq driver
	396	*
	397	* Initializes the SpeedStep support. Returns -ENODEV on unsupported
	398	* BIOS, -EINVAL on problems during initiatization, and zero on
	399	* success.
	400	*/
	401	static int __init speedstep_init(void)
	402	{
fa8031ae AK	403	if (!x86_match_cpu(ss_smi_ids))
	404	return -ENODEV;
	405
1da177e4 LT	406	speedstep_processor = speedstep_detect_processor();
	407
	408	switch (speedstep_processor) {
bbfebd66 DJ	409	case SPEEDSTEP_CPU_PIII_T:
	410	case SPEEDSTEP_CPU_PIII_C:
	411	case SPEEDSTEP_CPU_PIII_C_EARLY:
1da177e4 LT	412	break;
	413	default:
	414	speedstep_processor = 0;
	415	}
	416
	417	if (!speedstep_processor) {
2d06d8c4	418	pr_debug("No supported Intel CPU detected.\n");
1da177e4 LT	419	return -ENODEV;
	420	}
	421
2d06d8c4 DB	422	pr_debug("signature:0x%.8ulx, command:0x%.8ulx, "
2d06d8c4 DB	423	"event:0x%.8ulx, perf_level:0x%.8ulx.\n",
bbfebd66 DJ	424	ist_info.signature, ist_info.command,
bbfebd66 DJ	425	ist_info.event, ist_info.perf_level);
1da177e4	426
32ee8c3e	427	/* Error if no IST-SMI BIOS or no PARM
1da177e4	428	sig= 'ISGE' aka 'Intel Speedstep Gate E' */
32ee8c3e	429	if ((ist_info.signature != 0x47534943) && (
1da177e4 LT	430	(smi_port == 0) \|\| (smi_cmd == 0)))
	431	return -ENODEV;
	432
	433	if (smi_sig == 1)
	434	smi_sig = 0x47534943;
	435	else
	436	smi_sig = ist_info.signature;
	437
	438	/* setup smi_port from MODLULE_PARM or BIOS */
32ee8c3e	439	if ((smi_port > 0xff) \|\| (smi_port < 0))
1da177e4	440	return -EINVAL;
32ee8c3e	441	else if (smi_port == 0)
1da177e4	442	smi_port = ist_info.command & 0xff;
1da177e4	443
32ee8c3e	444	if ((smi_cmd > 0xff) \|\| (smi_cmd < 0))
1da177e4	445	return -EINVAL;
32ee8c3e	446	else if (smi_cmd == 0)
1da177e4	447	smi_cmd = (ist_info.command >> 16) & 0xff;
1da177e4 LT	448
	449	return cpufreq_register_driver(&speedstep_driver);
	450	}
	451
	452
	453	/**
	454	* speedstep_exit - unregisters SpeedStep support
	455	*
	456	* Unregisters SpeedStep support.
	457	*/
	458	static void __exit speedstep_exit(void)
	459	{
	460	cpufreq_unregister_driver(&speedstep_driver);
	461	}
	462
bbfebd66 DJ	463	module_param(smi_port, int, 0444);
	464	module_param(smi_cmd, int, 0444);
	465	module_param(smi_sig, uint, 0444);
1da177e4	466
bbfebd66 DJ	467	MODULE_PARM_DESC(smi_port, "Override the BIOS-given IST port with this value "
	468	"-- Intel's default setting is 0xb2");
	469	MODULE_PARM_DESC(smi_cmd, "Override the BIOS-given IST command with this value "
	470	"-- Intel's default setting is 0x82");
	471	MODULE_PARM_DESC(smi_sig, "Set to 1 to fake the IST signature when using the "
	472	"SMI interface.");
1da177e4	473
bbfebd66 DJ	474	MODULE_AUTHOR("Hiroshi Miura");
	475	MODULE_DESCRIPTION("Speedstep driver for IST applet SMI interface.");
	476	MODULE_LICENSE("GPL");
1da177e4 LT	477
	478	module_init(speedstep_init);
	479	module_exit(speedstep_exit);