[GitHub/mt8127/android_kernel_alcatel_ttab.git] / arch / x86 / kernel / cpu / 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

#define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_DRIVER, \
		"speedstep-smi", msg)

/**
 * 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);

	dprintk("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"
	);

	dprintk("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)) {
		dprintk("bug #1422 -- can't read freqs from BIOS\n");
		return -ENODEV;
	}

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

	dprintk("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)
	);

	dprintk("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);

	dprintk("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)
	);

	dprintk("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);

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

	do {
		if (retry) {
			dprintk("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)
		dprintk("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) {
		dprintk("fails in aquiring 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 */
		dprintk("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) {
			dprintk("could not detect two different speeds"
					" -- aborting.\n");
			return result;
		} else
			dprintk("workaround worked.\n");
	}

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

	dprintk("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)
		dprintk("fails in re-aquiring 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) {
		dprintk("No supported Intel CPU detected.\n");
		return -ENODEV;
	}

	dprintk("signature:0x%.8lx, command:0x%.8lx, "
		"event:0x%.8lx, perf_level:0x%.8lx.\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
bbfebd66 DJ	58	#define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_DRIVER, \
bbfebd66 DJ	59	"speedstep-smi", msg)
1da177e4 LT	60
	61	/**
	62	* speedstep_smi_ownership
	63	*/
bbfebd66	64	static int speedstep_smi_ownership(void)
1da177e4	65	{
c6e8256a	66	u32 command, result, magic, dummy;
1da177e4 LT	67	u32 function = GET_SPEEDSTEP_OWNER;
	68	unsigned char magic_data[] = "Copyright (c) 1999 Intel Corporation";
	69
	70	command = (smi_sig & 0xffffff00) \| (smi_cmd & 0xff);
	71	magic = virt_to_phys(magic_data);
	72
bbfebd66 DJ	73	dprintk("trying to obtain ownership with command %x at port %x\n",
bbfebd66 DJ	74	command, smi_port);
1da177e4 LT	75
1da177e4 LT	76	__asm__ __volatile__(
c6e8256a	77	"push %%ebp\n"
1da177e4	78	"out %%al, (%%dx)\n"
c6e8256a	79	"pop %%ebp\n"
bbfebd66 DJ	80	: "=D" (result),
	81	"=a" (dummy), "=b" (dummy), "=c" (dummy), "=d" (dummy),
	82	"=S" (dummy)
f081a529	83	: "a" (command), "b" (function), "c" (0), "d" (smi_port),
bbfebd66	84	"D" (0), "S" (magic)
f081a529	85	: "memory"
1da177e4 LT	86	);
	87
	88	dprintk("result is %x\n", result);
	89
	90	return result;
	91	}
	92
	93	/**
	94	* speedstep_smi_get_freqs - get SpeedStep preferred & current freq.
	95	* @low: the low frequency value is placed here
	96	* @high: the high frequency value is placed here
	97	*
	98	* Only available on later SpeedStep-enabled systems, returns false results or
	99	* even hangs [cf. bugme.osdl.org # 1422] on earlier systems. Empirical testing
	100	* shows that the latter occurs if !(ist_info.event & 0xFFFF).
	101	*/
bbfebd66	102	static int speedstep_smi_get_freqs(unsigned int low, unsigned int high)
1da177e4	103	{
c6e8256a	104	u32 command, result = 0, edi, high_mhz, low_mhz, dummy;
bbfebd66	105	u32 state = 0;
1da177e4 LT	106	u32 function = GET_SPEEDSTEP_FREQS;
	107
	108	if (!(ist_info.event & 0xFFFF)) {
ce38b51e	109	dprintk("bug #1422 -- can't read freqs from BIOS\n");
1da177e4 LT	110	return -ENODEV;
	111	}
	112
	113	command = (smi_sig & 0xffffff00) \| (smi_cmd & 0xff);
	114
bbfebd66 DJ	115	dprintk("trying to determine frequencies with command %x at port %x\n",
bbfebd66 DJ	116	command, smi_port);
1da177e4	117
c6e8256a SD	118	__asm__ __volatile__(
c6e8256a SD	119	"push %%ebp\n"
1da177e4	120	"out %%al, (%%dx)\n"
c6e8256a	121	"pop %%ebp"
bbfebd66 DJ	122	: "=a" (result),
	123	"=b" (high_mhz),
	124	"=c" (low_mhz),
	125	"=d" (state), "=D" (edi), "=S" (dummy)
	126	: "a" (command),
	127	"b" (function),
	128	"c" (state),
	129	"d" (smi_port), "S" (0), "D" (0)
1da177e4 LT	130	);
1da177e4 LT	131
bbfebd66 DJ	132	dprintk("result %x, low_freq %u, high_freq %u\n",
bbfebd66 DJ	133	result, low_mhz, high_mhz);
1da177e4 LT	134
	135	/* abort if results are obviously incorrect... */
	136	if ((high_mhz + low_mhz) < 600)
	137	return -EINVAL;
	138
	139	high = high_mhz 1000;
	140	low = low_mhz 1000;
	141
	142	return result;
32ee8c3e	143	}
1da177e4 LT	144
	145	/**
	146	* speedstep_get_state - set the SpeedStep state
	147	* @state: processor frequency state (SPEEDSTEP_LOW or SPEEDSTEP_HIGH)
	148	*
	149	*/
bbfebd66	150	static int speedstep_get_state(void)
1da177e4	151	{
bbfebd66	152	u32 function = GET_SPEEDSTEP_STATE;
c6e8256a	153	u32 result, state, edi, command, dummy;
1da177e4 LT	154
	155	command = (smi_sig & 0xffffff00) \| (smi_cmd & 0xff);
	156
bbfebd66 DJ	157	dprintk("trying to determine current setting with command %x "
bbfebd66 DJ	158	"at port %x\n", command, smi_port);
1da177e4	159
c6e8256a SD	160	__asm__ __volatile__(
c6e8256a SD	161	"push %%ebp\n"
1da177e4	162	"out %%al, (%%dx)\n"
c6e8256a	163	"pop %%ebp\n"
bbfebd66 DJ	164	: "=a" (result),
	165	"=b" (state), "=D" (edi),
	166	"=c" (dummy), "=d" (dummy), "=S" (dummy)
	167	: "a" (command), "b" (function), "c" (0),
	168	"d" (smi_port), "S" (0), "D" (0)
1da177e4 LT	169	);
	170
	171	dprintk("state is %x, result is %x\n", state, result);
	172
bbfebd66	173	return state & 1;
1da177e4 LT	174	}
	175
	176
	177	/**
	178	* speedstep_set_state - set the SpeedStep state
	179	* @state: new processor frequency state (SPEEDSTEP_LOW or SPEEDSTEP_HIGH)
	180	*
	181	*/
bbfebd66	182	static void speedstep_set_state(unsigned int state)
1da177e4	183	{
c6e8256a	184	unsigned int result = 0, command, new_state, dummy;
1da177e4	185	unsigned long flags;
bbfebd66	186	unsigned int function = SET_SPEEDSTEP_STATE;
1da177e4 LT	187	unsigned int retry = 0;
	188
	189	if (state > 0x1)
	190	return;
	191
	192	/* Disable IRQs */
	193	local_irq_save(flags);
	194
	195	command = (smi_sig & 0xffffff00) \| (smi_cmd & 0xff);
	196
bbfebd66 DJ	197	dprintk("trying to set frequency to state %u "
	198	"with command %x at port %x\n",
	199	state, command, smi_port);
1da177e4 LT	200
	201	do {
	202	if (retry) {
bbfebd66 DJ	203	dprintk("retry %u, previous result %u, waiting...\n",
bbfebd66 DJ	204	retry, result);
1da177e4 LT	205	mdelay(retry * 50);
	206	}
	207	retry++;
	208	__asm__ __volatile__(
c6e8256a	209	"push %%ebp\n"
1da177e4	210	"out %%al, (%%dx)\n"
c6e8256a	211	"pop %%ebp"
bbfebd66 DJ	212	: "=b" (new_state), "=D" (result),
	213	"=c" (dummy), "=a" (dummy),
	214	"=d" (dummy), "=S" (dummy)
	215	: "a" (command), "b" (function), "c" (state),
	216	"d" (smi_port), "S" (0), "D" (0)
1da177e4 LT	217	);
	218	} while ((new_state != state) && (retry <= SMI_TRIES));
	219
	220	/* enable IRQs */
	221	local_irq_restore(flags);
	222
bbfebd66 DJ	223	if (new_state == state)
	224	dprintk("change to %u MHz succeeded after %u tries "
	225	"with result %u\n",
	226	(speedstep_freqs[new_state].frequency / 1000),
	227	retry, result);
	228	else
	229	printk(KERN_ERR "cpufreq: change to state %u "
	230	"failed with new_state %u and result %u\n",
	231	state, new_state, result);
1da177e4 LT	232
	233	return;
	234	}
	235
	236
	237	/**
	238	* speedstep_target - set a new CPUFreq policy
	239	* @policy: new policy
	240	* @target_freq: new freq
32ee8c3e	241	* @relation:
1da177e4 LT	242	*
	243	* Sets a new CPUFreq policy/freq.
	244	*/
bbfebd66	245	static int speedstep_target(struct cpufreq_policy *policy,
1da177e4 LT	246	unsigned int target_freq, unsigned int relation)
	247	{
	248	unsigned int newstate = 0;
	249	struct cpufreq_freqs freqs;
	250
bbfebd66 DJ	251	if (cpufreq_frequency_table_target(policy, &speedstep_freqs[0],
bbfebd66 DJ	252	target_freq, relation, &newstate))
1da177e4 LT	253	return -EINVAL;
	254
	255	freqs.old = speedstep_freqs[speedstep_get_state()].frequency;
	256	freqs.new = speedstep_freqs[newstate].frequency;
	257	freqs.cpu = 0; /* speedstep.c is UP only driver */
	258
	259	if (freqs.old == freqs.new)
	260	return 0;
	261
	262	cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
	263	speedstep_set_state(newstate);
	264	cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
	265
	266	return 0;
	267	}
	268
	269
	270	/**
	271	* speedstep_verify - verifies a new CPUFreq policy
	272	* @policy: new policy
	273	*
	274	* Limit must be within speedstep_low_freq and speedstep_high_freq, with
	275	* at least one border included.
	276	*/
bbfebd66	277	static int speedstep_verify(struct cpufreq_policy *policy)
1da177e4 LT	278	{
	279	return cpufreq_frequency_table_verify(policy, &speedstep_freqs[0]);
	280	}
	281
	282
	283	static int speedstep_cpu_init(struct cpufreq_policy *policy)
	284	{
	285	int result;
bbfebd66 DJ	286	unsigned int speed, state;
bbfebd66 DJ	287	unsigned int low, high;
1da177e4 LT	288
	289	/* capability check */
	290	if (policy->cpu != 0)
	291	return -ENODEV;
	292
	293	result = speedstep_smi_ownership();
	294	if (result) {
	295	dprintk("fails in aquiring ownership of a SMI interface.\n");
	296	return -EINVAL;
	297	}
	298
	299	/* detect low and high frequency */
bbfebd66 DJ	300	low = &speedstep_freqs[SPEEDSTEP_LOW].frequency;
	301	high = &speedstep_freqs[SPEEDSTEP_HIGH].frequency;
	302
	303	result = speedstep_smi_get_freqs(low, high);
1da177e4	304	if (result) {
bbfebd66 DJ	305	/* fall back to speedstep_lib.c dection mechanism:
	306	* try both states out */
	307	dprintk("could not detect low and high frequencies "
	308	"by SMI call.\n");
1da177e4	309	result = speedstep_get_freqs(speedstep_processor,
bbfebd66	310	low, high,
1a10760c	311	NULL,
1da177e4 LT	312	&speedstep_set_state);
	313
	314	if (result) {
bbfebd66 DJ	315	dprintk("could not detect two different speeds"
bbfebd66 DJ	316	" -- aborting.\n");
1da177e4 LT	317	return result;
	318	} else
	319	dprintk("workaround worked.\n");
	320	}
	321
	322	/* get current speed setting */
	323	state = speedstep_get_state();
	324	speed = speedstep_freqs[state].frequency;
	325
32ee8c3e	326	dprintk("currently at %s speed setting - %i MHz\n",
bbfebd66 DJ	327	(speed == speedstep_freqs[SPEEDSTEP_LOW].frequency)
bbfebd66 DJ	328	? "low" : "high",
1da177e4 LT	329	(speed / 1000));
	330
	331	/* cpuinfo and default policy values */
1da177e4 LT	332	policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
	333	policy->cur = speed;
	334
	335	result = cpufreq_frequency_table_cpuinfo(policy, speedstep_freqs);
	336	if (result)
bbfebd66	337	return result;
1da177e4	338
32ee8c3e	339	cpufreq_frequency_table_get_attr(speedstep_freqs, policy->cpu);
1da177e4 LT	340
	341	return 0;
	342	}
	343
	344	static int speedstep_cpu_exit(struct cpufreq_policy *policy)
	345	{
	346	cpufreq_frequency_table_put_attr(policy->cpu);
	347	return 0;
	348	}
	349
	350	static unsigned int speedstep_get(unsigned int cpu)
	351	{
	352	if (cpu)
	353	return -ENODEV;
bbfebd66	354	return speedstep_get_frequency(speedstep_processor);
1da177e4 LT	355	}
	356
	357
	358	static int speedstep_resume(struct cpufreq_policy *policy)
	359	{
	360	int result = speedstep_smi_ownership();
	361
	362	if (result)
	363	dprintk("fails in re-aquiring ownership of a SMI interface.\n");
	364
	365	return result;
	366	}
	367
bbfebd66	368	static struct freq_attr *speedstep_attr[] = {
1da177e4 LT	369	&cpufreq_freq_attr_scaling_available_freqs,
	370	NULL,
	371	};
	372
221dee28	373	static struct cpufreq_driver speedstep_driver = {
1da177e4	374	.name = "speedstep-smi",
32ee8c3e DJ	375	.verify = speedstep_verify,
32ee8c3e DJ	376	.target = speedstep_target,
1da177e4 LT	377	.init = speedstep_cpu_init,
	378	.exit = speedstep_cpu_exit,
	379	.get = speedstep_get,
	380	.resume = speedstep_resume,
	381	.owner = THIS_MODULE,
	382	.attr = speedstep_attr,
	383	};
	384
	385	/**
	386	* speedstep_init - initializes the SpeedStep CPUFreq driver
	387	*
	388	* Initializes the SpeedStep support. Returns -ENODEV on unsupported
	389	* BIOS, -EINVAL on problems during initiatization, and zero on
	390	* success.
	391	*/
	392	static int __init speedstep_init(void)
	393	{
	394	speedstep_processor = speedstep_detect_processor();
	395
	396	switch (speedstep_processor) {
bbfebd66 DJ	397	case SPEEDSTEP_CPU_PIII_T:
	398	case SPEEDSTEP_CPU_PIII_C:
	399	case SPEEDSTEP_CPU_PIII_C_EARLY:
1da177e4 LT	400	break;
	401	default:
	402	speedstep_processor = 0;
	403	}
	404
	405	if (!speedstep_processor) {
bbfebd66	406	dprintk("No supported Intel CPU detected.\n");
1da177e4 LT	407	return -ENODEV;
	408	}
	409
bbfebd66 DJ	410	dprintk("signature:0x%.8lx, command:0x%.8lx, "
	411	"event:0x%.8lx, perf_level:0x%.8lx.\n",
	412	ist_info.signature, ist_info.command,
	413	ist_info.event, ist_info.perf_level);
1da177e4	414
32ee8c3e	415	/* Error if no IST-SMI BIOS or no PARM
1da177e4	416	sig= 'ISGE' aka 'Intel Speedstep Gate E' */
32ee8c3e	417	if ((ist_info.signature != 0x47534943) && (
1da177e4 LT	418	(smi_port == 0) \|\| (smi_cmd == 0)))
	419	return -ENODEV;
	420
	421	if (smi_sig == 1)
	422	smi_sig = 0x47534943;
	423	else
	424	smi_sig = ist_info.signature;
	425
	426	/* setup smi_port from MODLULE_PARM or BIOS */
32ee8c3e	427	if ((smi_port > 0xff) \|\| (smi_port < 0))
1da177e4	428	return -EINVAL;
32ee8c3e	429	else if (smi_port == 0)
1da177e4	430	smi_port = ist_info.command & 0xff;
1da177e4	431
32ee8c3e	432	if ((smi_cmd > 0xff) \|\| (smi_cmd < 0))
1da177e4	433	return -EINVAL;
32ee8c3e	434	else if (smi_cmd == 0)
1da177e4	435	smi_cmd = (ist_info.command >> 16) & 0xff;
1da177e4 LT	436
	437	return cpufreq_register_driver(&speedstep_driver);
	438	}
	439
	440
	441	/**
	442	* speedstep_exit - unregisters SpeedStep support
	443	*
	444	* Unregisters SpeedStep support.
	445	*/
	446	static void __exit speedstep_exit(void)
	447	{
	448	cpufreq_unregister_driver(&speedstep_driver);
	449	}
	450
bbfebd66 DJ	451	module_param(smi_port, int, 0444);
	452	module_param(smi_cmd, int, 0444);
	453	module_param(smi_sig, uint, 0444);
1da177e4	454
bbfebd66 DJ	455	MODULE_PARM_DESC(smi_port, "Override the BIOS-given IST port with this value "
	456	"-- Intel's default setting is 0xb2");
	457	MODULE_PARM_DESC(smi_cmd, "Override the BIOS-given IST command with this value "
	458	"-- Intel's default setting is 0x82");
	459	MODULE_PARM_DESC(smi_sig, "Set to 1 to fake the IST signature when using the "
	460	"SMI interface.");
1da177e4	461
bbfebd66 DJ	462	MODULE_AUTHOR("Hiroshi Miura");
	463	MODULE_DESCRIPTION("Speedstep driver for IST applet SMI interface.");
	464	MODULE_LICENSE("GPL");
1da177e4 LT	465
	466	module_init(speedstep_init);
	467	module_exit(speedstep_exit);