[linux-2.6-block.git] / drivers / cpufreq / speedstep-smi.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Intel SpeedStep SMI driver.
 *
 * (C) 2003  Hiroshi Miura <miura@da-cha.org>
 */


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

#define pr_fmt(fmt) "cpufreq: " fmt

#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[] = {
	{0, SPEEDSTEP_HIGH,	0},
	{0, SPEEDSTEP_LOW,	0},
	{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_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 */
	preempt_disable();
	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) {
			/*
			 * We need to enable interrupts, otherwise the blockage
			 * won't resolve.
			 *
			 * We disable preemption so that other processes don't
			 * run. If other processes were running, they could
			 * submit more DMA requests, making the blockage worse.
			 */
			pr_debug("retry %u, previous result %u, waiting...\n",
					retry, result);
			local_irq_enable();
			mdelay(retry * 50);
			local_irq_disable();
		}
		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);
	preempt_enable();

	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
		pr_err("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
 * @index: index of new freq
 *
 * Sets a new CPUFreq policy/freq.
 */
static int speedstep_target(struct cpufreq_policy *policy, unsigned int index)
{
	speedstep_set_state(index);

	return 0;
}


static int speedstep_cpu_init(struct cpufreq_policy *policy)
{
	int result;
	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");
	}

	policy->freq_table = speedstep_freqs;

	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 cpufreq_driver speedstep_driver = {
	.name		= "speedstep-smi",
	.flags		= CPUFREQ_NO_AUTO_DYNAMIC_SWITCHING,
	.verify		= cpufreq_generic_frequency_table_verify,
	.target_index	= speedstep_target,
	.init		= speedstep_cpu_init,
	.get		= speedstep_get,
	.resume		= speedstep_resume,
	.attr		= cpufreq_generic_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%.8x, command:0x%.8x, "
		"event:0x%.8x, perf_level:0x%.8x.\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_hw(smi_port, int, ioport, 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
4f19048f	1	// SPDX-License-Identifier: GPL-2.0-only
1da177e4 LT	2	/*
	3	* Intel SpeedStep SMI driver.
	4	*
	5	* (C) 2003 Hiroshi Miura <miura@da-cha.org>
1da177e4 LT	6	*/
	7
	8
	9	/*********************************************************************
	10	* SPEEDSTEP - DEFINITIONS *
	11	*********************************************************************/
	12
1c5864e2 JP	13	#define pr_fmt(fmt) "cpufreq: " fmt
1c5864e2 JP	14
1da177e4	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[] = {
7f4b0461 VK	45	{0, SPEEDSTEP_HIGH, 0},
	46	{0, SPEEDSTEP_LOW, 0},
	47	{0, 0, CPUFREQ_TABLE_END},
1da177e4 LT	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	142
1da177e4 LT	143	/**
	144	* speedstep_set_state - set the SpeedStep state
	145	* @state: new processor frequency state (SPEEDSTEP_LOW or SPEEDSTEP_HIGH)
	146	*
	147	*/
bbfebd66	148	static void speedstep_set_state(unsigned int state)
1da177e4	149	{
c6e8256a	150	unsigned int result = 0, command, new_state, dummy;
1da177e4	151	unsigned long flags;
bbfebd66	152	unsigned int function = SET_SPEEDSTEP_STATE;
1da177e4 LT	153	unsigned int retry = 0;
	154
	155	if (state > 0x1)
	156	return;
	157
	158	/* Disable IRQs */
d4d4eda2	159	preempt_disable();
1da177e4 LT	160	local_irq_save(flags);
	161
	162	command = (smi_sig & 0xffffff00) \| (smi_cmd & 0xff);
	163
2d06d8c4	164	pr_debug("trying to set frequency to state %u "
bbfebd66 DJ	165	"with command %x at port %x\n",
bbfebd66 DJ	166	state, command, smi_port);
1da177e4 LT	167
	168	do {
	169	if (retry) {
d4d4eda2 MP	170	/*
	171	* We need to enable interrupts, otherwise the blockage
	172	* won't resolve.
	173	*
	174	* We disable preemption so that other processes don't
	175	* run. If other processes were running, they could
	176	* submit more DMA requests, making the blockage worse.
	177	*/
2d06d8c4	178	pr_debug("retry %u, previous result %u, waiting...\n",
bbfebd66	179	retry, result);
d4d4eda2	180	local_irq_enable();
1da177e4	181	mdelay(retry * 50);
d4d4eda2	182	local_irq_disable();
1da177e4 LT	183	}
	184	retry++;
	185	__asm__ __volatile__(
c6e8256a	186	"push %%ebp\n"
1da177e4	187	"out %%al, (%%dx)\n"
c6e8256a	188	"pop %%ebp"
bbfebd66 DJ	189	: "=b" (new_state), "=D" (result),
	190	"=c" (dummy), "=a" (dummy),
	191	"=d" (dummy), "=S" (dummy)
	192	: "a" (command), "b" (function), "c" (state),
	193	"d" (smi_port), "S" (0), "D" (0)
1da177e4 LT	194	);
	195	} while ((new_state != state) && (retry <= SMI_TRIES));
	196
	197	/* enable IRQs */
	198	local_irq_restore(flags);
d4d4eda2	199	preempt_enable();
1da177e4	200
bbfebd66	201	if (new_state == state)
2d06d8c4	202	pr_debug("change to %u MHz succeeded after %u tries "
bbfebd66 DJ	203	"with result %u\n",
	204	(speedstep_freqs[new_state].frequency / 1000),
	205	retry, result);
	206	else
1c5864e2	207	pr_err("change to state %u failed with new_state %u and result %u\n",
b49c22a6	208	state, new_state, result);
1da177e4 LT	209
	210	return;
	211	}
	212
	213
	214	/**
	215	* speedstep_target - set a new CPUFreq policy
	216	* @policy: new policy
9c0ebcf7	217	* @index: index of new freq
1da177e4 LT	218	*
	219	* Sets a new CPUFreq policy/freq.
	220	*/
9c0ebcf7	221	static int speedstep_target(struct cpufreq_policy *policy, unsigned int index)
1da177e4	222	{
9c0ebcf7	223	speedstep_set_state(index);
1da177e4 LT	224
	225	return 0;
	226	}
	227
	228
1da177e4 LT	229	static int speedstep_cpu_init(struct cpufreq_policy *policy)
	230	{
	231	int result;
bbfebd66	232	unsigned int low, high;
1da177e4 LT	233
	234	/* capability check */
	235	if (policy->cpu != 0)
	236	return -ENODEV;
	237
	238	result = speedstep_smi_ownership();
	239	if (result) {
2d06d8c4	240	pr_debug("fails in acquiring ownership of a SMI interface.\n");
1da177e4 LT	241	return -EINVAL;
	242	}
	243
	244	/* detect low and high frequency */
bbfebd66 DJ	245	low = &speedstep_freqs[SPEEDSTEP_LOW].frequency;
	246	high = &speedstep_freqs[SPEEDSTEP_HIGH].frequency;
	247
	248	result = speedstep_smi_get_freqs(low, high);
1da177e4	249	if (result) {
bbfebd66 DJ	250	/* fall back to speedstep_lib.c dection mechanism:
bbfebd66 DJ	251	* try both states out */
2d06d8c4	252	pr_debug("could not detect low and high frequencies "
bbfebd66	253	"by SMI call.\n");
1da177e4	254	result = speedstep_get_freqs(speedstep_processor,
bbfebd66	255	low, high,
1a10760c	256	NULL,
1da177e4 LT	257	&speedstep_set_state);
	258
	259	if (result) {
2d06d8c4	260	pr_debug("could not detect two different speeds"
bbfebd66	261	" -- aborting.\n");
1da177e4 LT	262	return result;
1da177e4 LT	263	} else
2d06d8c4	264	pr_debug("workaround worked.\n");
1da177e4 LT	265	}
1da177e4 LT	266
2d28b036 VK	267	policy->freq_table = speedstep_freqs;
	268
	269	return 0;
1da177e4 LT	270	}
1da177e4 LT	271
1da177e4 LT	272	static unsigned int speedstep_get(unsigned int cpu)
	273	{
	274	if (cpu)
	275	return -ENODEV;
bbfebd66	276	return speedstep_get_frequency(speedstep_processor);
1da177e4 LT	277	}
	278
	279
	280	static int speedstep_resume(struct cpufreq_policy *policy)
	281	{
	282	int result = speedstep_smi_ownership();
	283
	284	if (result)
2d06d8c4	285	pr_debug("fails in re-acquiring ownership of a SMI interface.\n");
1da177e4 LT	286
	287	return result;
	288	}
	289
221dee28	290	static struct cpufreq_driver speedstep_driver = {
1da177e4	291	.name = "speedstep-smi",
fe829ed8	292	.flags = CPUFREQ_NO_AUTO_DYNAMIC_SWITCHING,
3be1394a	293	.verify = cpufreq_generic_frequency_table_verify,
9c0ebcf7	294	.target_index = speedstep_target,
1da177e4	295	.init = speedstep_cpu_init,
1da177e4 LT	296	.get = speedstep_get,
1da177e4 LT	297	.resume = speedstep_resume,
3be1394a	298	.attr = cpufreq_generic_attr,
1da177e4 LT	299	};
1da177e4 LT	300
fa8031ae AK	301	static const struct x86_cpu_id ss_smi_ids[] = {
	302	{ X86_VENDOR_INTEL, 6, 0xb, },
	303	{ X86_VENDOR_INTEL, 6, 0x8, },
	304	{ X86_VENDOR_INTEL, 15, 2 },
	305	{}
	306	};
	307	#if 0
	308	/* Not auto loaded currently */
	309	MODULE_DEVICE_TABLE(x86cpu, ss_smi_ids);
	310	#endif
	311
1da177e4 LT	312	/**
	313	* speedstep_init - initializes the SpeedStep CPUFreq driver
	314	*
	315	* Initializes the SpeedStep support. Returns -ENODEV on unsupported
	316	* BIOS, -EINVAL on problems during initiatization, and zero on
	317	* success.
	318	*/
	319	static int __init speedstep_init(void)
	320	{
fa8031ae AK	321	if (!x86_match_cpu(ss_smi_ids))
	322	return -ENODEV;
	323
1da177e4 LT	324	speedstep_processor = speedstep_detect_processor();
	325
	326	switch (speedstep_processor) {
bbfebd66 DJ	327	case SPEEDSTEP_CPU_PIII_T:
	328	case SPEEDSTEP_CPU_PIII_C:
	329	case SPEEDSTEP_CPU_PIII_C_EARLY:
1da177e4 LT	330	break;
	331	default:
	332	speedstep_processor = 0;
	333	}
	334
	335	if (!speedstep_processor) {
2d06d8c4	336	pr_debug("No supported Intel CPU detected.\n");
1da177e4 LT	337	return -ENODEV;
	338	}
	339
a5f30eba HW	340	pr_debug("signature:0x%.8x, command:0x%.8x, "
a5f30eba HW	341	"event:0x%.8x, perf_level:0x%.8x.\n",
bbfebd66 DJ	342	ist_info.signature, ist_info.command,
bbfebd66 DJ	343	ist_info.event, ist_info.perf_level);
1da177e4	344
32ee8c3e	345	/* Error if no IST-SMI BIOS or no PARM
1da177e4	346	sig= 'ISGE' aka 'Intel Speedstep Gate E' */
32ee8c3e	347	if ((ist_info.signature != 0x47534943) && (
1da177e4 LT	348	(smi_port == 0) \|\| (smi_cmd == 0)))
	349	return -ENODEV;
	350
	351	if (smi_sig == 1)
	352	smi_sig = 0x47534943;
	353	else
	354	smi_sig = ist_info.signature;
	355
	356	/* setup smi_port from MODLULE_PARM or BIOS */
32ee8c3e	357	if ((smi_port > 0xff) \|\| (smi_port < 0))
1da177e4	358	return -EINVAL;
32ee8c3e	359	else if (smi_port == 0)
1da177e4	360	smi_port = ist_info.command & 0xff;
1da177e4	361
32ee8c3e	362	if ((smi_cmd > 0xff) \|\| (smi_cmd < 0))
1da177e4	363	return -EINVAL;
32ee8c3e	364	else if (smi_cmd == 0)
1da177e4	365	smi_cmd = (ist_info.command >> 16) & 0xff;
1da177e4 LT	366
	367	return cpufreq_register_driver(&speedstep_driver);
	368	}
	369
	370
	371	/**
	372	* speedstep_exit - unregisters SpeedStep support
	373	*
	374	* Unregisters SpeedStep support.
	375	*/
	376	static void __exit speedstep_exit(void)
	377	{
	378	cpufreq_unregister_driver(&speedstep_driver);
	379	}
	380
40059ec6	381	module_param_hw(smi_port, int, ioport, 0444);
bbfebd66 DJ	382	module_param(smi_cmd, int, 0444);
bbfebd66 DJ	383	module_param(smi_sig, uint, 0444);
1da177e4	384
bbfebd66 DJ	385	MODULE_PARM_DESC(smi_port, "Override the BIOS-given IST port with this value "
	386	"-- Intel's default setting is 0xb2");
	387	MODULE_PARM_DESC(smi_cmd, "Override the BIOS-given IST command with this value "
	388	"-- Intel's default setting is 0x82");
	389	MODULE_PARM_DESC(smi_sig, "Set to 1 to fake the IST signature when using the "
	390	"SMI interface.");
1da177e4	391
bbfebd66 DJ	392	MODULE_AUTHOR("Hiroshi Miura");
	393	MODULE_DESCRIPTION("Speedstep driver for IST applet SMI interface.");
	394	MODULE_LICENSE("GPL");
1da177e4 LT	395
	396	module_init(speedstep_init);
	397	module_exit(speedstep_exit);