[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 "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,
};

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