[linux-2.6-block.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/slab.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 unsigned int 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 LT	20	#include <linux/slab.h>
1da177e4 LT	21	#include <linux/delay.h>
bbfebd66	22	#include <linux/io.h>
1da177e4 LT	23	#include <asm/ist.h>
	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 */
bbfebd66	38	static unsigned int 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
bbfebd66 DJ	59	#define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_DRIVER, \
bbfebd66 DJ	60	"speedstep-smi", msg)
1da177e4 LT	61
	62	/**
	63	* speedstep_smi_ownership
	64	*/
bbfebd66	65	static int speedstep_smi_ownership(void)
1da177e4	66	{
c6e8256a	67	u32 command, result, magic, dummy;
1da177e4 LT	68	u32 function = GET_SPEEDSTEP_OWNER;
	69	unsigned char magic_data[] = "Copyright (c) 1999 Intel Corporation";
	70
	71	command = (smi_sig & 0xffffff00) \| (smi_cmd & 0xff);
	72	magic = virt_to_phys(magic_data);
	73
bbfebd66 DJ	74	dprintk("trying to obtain ownership with command %x at port %x\n",
bbfebd66 DJ	75	command, smi_port);
1da177e4 LT	76
1da177e4 LT	77	__asm__ __volatile__(
c6e8256a	78	"push %%ebp\n"
1da177e4	79	"out %%al, (%%dx)\n"
c6e8256a	80	"pop %%ebp\n"
bbfebd66 DJ	81	: "=D" (result),
	82	"=a" (dummy), "=b" (dummy), "=c" (dummy), "=d" (dummy),
	83	"=S" (dummy)
f081a529	84	: "a" (command), "b" (function), "c" (0), "d" (smi_port),
bbfebd66	85	"D" (0), "S" (magic)
f081a529	86	: "memory"
1da177e4 LT	87	);
	88
	89	dprintk("result is %x\n", result);
	90
	91	return result;
	92	}
	93
	94	/**
	95	* speedstep_smi_get_freqs - get SpeedStep preferred & current freq.
	96	* @low: the low frequency value is placed here
	97	* @high: the high frequency value is placed here
	98	*
	99	* Only available on later SpeedStep-enabled systems, returns false results or
	100	* even hangs [cf. bugme.osdl.org # 1422] on earlier systems. Empirical testing
	101	* shows that the latter occurs if !(ist_info.event & 0xFFFF).
	102	*/
bbfebd66	103	static int speedstep_smi_get_freqs(unsigned int low, unsigned int high)
1da177e4	104	{
c6e8256a	105	u32 command, result = 0, edi, high_mhz, low_mhz, dummy;
bbfebd66	106	u32 state = 0;
1da177e4 LT	107	u32 function = GET_SPEEDSTEP_FREQS;
	108
	109	if (!(ist_info.event & 0xFFFF)) {
ce38b51e	110	dprintk("bug #1422 -- can't read freqs from BIOS\n");
1da177e4 LT	111	return -ENODEV;
	112	}
	113
	114	command = (smi_sig & 0xffffff00) \| (smi_cmd & 0xff);
	115
bbfebd66 DJ	116	dprintk("trying to determine frequencies with command %x at port %x\n",
bbfebd66 DJ	117	command, smi_port);
1da177e4	118
c6e8256a SD	119	__asm__ __volatile__(
c6e8256a SD	120	"push %%ebp\n"
1da177e4	121	"out %%al, (%%dx)\n"
c6e8256a	122	"pop %%ebp"
bbfebd66 DJ	123	: "=a" (result),
	124	"=b" (high_mhz),
	125	"=c" (low_mhz),
	126	"=d" (state), "=D" (edi), "=S" (dummy)
	127	: "a" (command),
	128	"b" (function),
	129	"c" (state),
	130	"d" (smi_port), "S" (0), "D" (0)
1da177e4 LT	131	);
1da177e4 LT	132
bbfebd66 DJ	133	dprintk("result %x, low_freq %u, high_freq %u\n",
bbfebd66 DJ	134	result, low_mhz, high_mhz);
1da177e4 LT	135
	136	/* abort if results are obviously incorrect... */
	137	if ((high_mhz + low_mhz) < 600)
	138	return -EINVAL;
	139
	140	high = high_mhz 1000;
	141	low = low_mhz 1000;
	142
	143	return result;
32ee8c3e	144	}
1da177e4 LT	145
	146	/**
	147	* speedstep_get_state - set the SpeedStep state
	148	* @state: processor frequency state (SPEEDSTEP_LOW or SPEEDSTEP_HIGH)
	149	*
	150	*/
bbfebd66	151	static int speedstep_get_state(void)
1da177e4	152	{
bbfebd66	153	u32 function = GET_SPEEDSTEP_STATE;
c6e8256a	154	u32 result, state, edi, command, dummy;
1da177e4 LT	155
	156	command = (smi_sig & 0xffffff00) \| (smi_cmd & 0xff);
	157
bbfebd66 DJ	158	dprintk("trying to determine current setting with command %x "
bbfebd66 DJ	159	"at port %x\n", command, smi_port);
1da177e4	160
c6e8256a SD	161	__asm__ __volatile__(
c6e8256a SD	162	"push %%ebp\n"
1da177e4	163	"out %%al, (%%dx)\n"
c6e8256a	164	"pop %%ebp\n"
bbfebd66 DJ	165	: "=a" (result),
	166	"=b" (state), "=D" (edi),
	167	"=c" (dummy), "=d" (dummy), "=S" (dummy)
	168	: "a" (command), "b" (function), "c" (0),
	169	"d" (smi_port), "S" (0), "D" (0)
1da177e4 LT	170	);
	171
	172	dprintk("state is %x, result is %x\n", state, result);
	173
bbfebd66	174	return state & 1;
1da177e4 LT	175	}
	176
	177
	178	/**
	179	* speedstep_set_state - set the SpeedStep state
	180	* @state: new processor frequency state (SPEEDSTEP_LOW or SPEEDSTEP_HIGH)
	181	*
	182	*/
bbfebd66	183	static void speedstep_set_state(unsigned int state)
1da177e4	184	{
c6e8256a	185	unsigned int result = 0, command, new_state, dummy;
1da177e4	186	unsigned long flags;
bbfebd66	187	unsigned int function = SET_SPEEDSTEP_STATE;
1da177e4 LT	188	unsigned int retry = 0;
	189
	190	if (state > 0x1)
	191	return;
	192
	193	/* Disable IRQs */
	194	local_irq_save(flags);
	195
	196	command = (smi_sig & 0xffffff00) \| (smi_cmd & 0xff);
	197
bbfebd66 DJ	198	dprintk("trying to set frequency to state %u "
	199	"with command %x at port %x\n",
	200	state, command, smi_port);
1da177e4 LT	201
	202	do {
	203	if (retry) {
bbfebd66 DJ	204	dprintk("retry %u, previous result %u, waiting...\n",
bbfebd66 DJ	205	retry, result);
1da177e4 LT	206	mdelay(retry * 50);
	207	}
	208	retry++;
	209	__asm__ __volatile__(
c6e8256a	210	"push %%ebp\n"
1da177e4	211	"out %%al, (%%dx)\n"
c6e8256a	212	"pop %%ebp"
bbfebd66 DJ	213	: "=b" (new_state), "=D" (result),
	214	"=c" (dummy), "=a" (dummy),
	215	"=d" (dummy), "=S" (dummy)
	216	: "a" (command), "b" (function), "c" (state),
	217	"d" (smi_port), "S" (0), "D" (0)
1da177e4 LT	218	);
	219	} while ((new_state != state) && (retry <= SMI_TRIES));
	220
	221	/* enable IRQs */
	222	local_irq_restore(flags);
	223
bbfebd66 DJ	224	if (new_state == state)
	225	dprintk("change to %u MHz succeeded after %u tries "
	226	"with result %u\n",
	227	(speedstep_freqs[new_state].frequency / 1000),
	228	retry, result);
	229	else
	230	printk(KERN_ERR "cpufreq: change to state %u "
	231	"failed with new_state %u and result %u\n",
	232	state, new_state, result);
1da177e4 LT	233
	234	return;
	235	}
	236
	237
	238	/**
	239	* speedstep_target - set a new CPUFreq policy
	240	* @policy: new policy
	241	* @target_freq: new freq
32ee8c3e	242	* @relation:
1da177e4 LT	243	*
	244	* Sets a new CPUFreq policy/freq.
	245	*/
bbfebd66	246	static int speedstep_target(struct cpufreq_policy *policy,
1da177e4 LT	247	unsigned int target_freq, unsigned int relation)
	248	{
	249	unsigned int newstate = 0;
	250	struct cpufreq_freqs freqs;
	251
bbfebd66 DJ	252	if (cpufreq_frequency_table_target(policy, &speedstep_freqs[0],
bbfebd66 DJ	253	target_freq, relation, &newstate))
1da177e4 LT	254	return -EINVAL;
	255
	256	freqs.old = speedstep_freqs[speedstep_get_state()].frequency;
	257	freqs.new = speedstep_freqs[newstate].frequency;
	258	freqs.cpu = 0; /* speedstep.c is UP only driver */
	259
	260	if (freqs.old == freqs.new)
	261	return 0;
	262
	263	cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
	264	speedstep_set_state(newstate);
	265	cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
	266
	267	return 0;
	268	}
	269
	270
	271	/**
	272	* speedstep_verify - verifies a new CPUFreq policy
	273	* @policy: new policy
	274	*
	275	* Limit must be within speedstep_low_freq and speedstep_high_freq, with
	276	* at least one border included.
	277	*/
bbfebd66	278	static int speedstep_verify(struct cpufreq_policy *policy)
1da177e4 LT	279	{
	280	return cpufreq_frequency_table_verify(policy, &speedstep_freqs[0]);
	281	}
	282
	283
	284	static int speedstep_cpu_init(struct cpufreq_policy *policy)
	285	{
	286	int result;
bbfebd66 DJ	287	unsigned int speed, state;
bbfebd66 DJ	288	unsigned int low, high;
1da177e4 LT	289
	290	/* capability check */
	291	if (policy->cpu != 0)
	292	return -ENODEV;
	293
	294	result = speedstep_smi_ownership();
	295	if (result) {
	296	dprintk("fails in aquiring ownership of a SMI interface.\n");
	297	return -EINVAL;
	298	}
	299
	300	/* detect low and high frequency */
bbfebd66 DJ	301	low = &speedstep_freqs[SPEEDSTEP_LOW].frequency;
	302	high = &speedstep_freqs[SPEEDSTEP_HIGH].frequency;
	303
	304	result = speedstep_smi_get_freqs(low, high);
1da177e4	305	if (result) {
bbfebd66 DJ	306	/* fall back to speedstep_lib.c dection mechanism:
	307	* try both states out */
	308	dprintk("could not detect low and high frequencies "
	309	"by SMI call.\n");
1da177e4	310	result = speedstep_get_freqs(speedstep_processor,
bbfebd66	311	low, high,
1a10760c	312	NULL,
1da177e4 LT	313	&speedstep_set_state);
	314
	315	if (result) {
bbfebd66 DJ	316	dprintk("could not detect two different speeds"
bbfebd66 DJ	317	" -- aborting.\n");
1da177e4 LT	318	return result;
	319	} else
	320	dprintk("workaround worked.\n");
	321	}
	322
	323	/* get current speed setting */
	324	state = speedstep_get_state();
	325	speed = speedstep_freqs[state].frequency;
	326
32ee8c3e	327	dprintk("currently at %s speed setting - %i MHz\n",
bbfebd66 DJ	328	(speed == speedstep_freqs[SPEEDSTEP_LOW].frequency)
bbfebd66 DJ	329	? "low" : "high",
1da177e4 LT	330	(speed / 1000));
	331
	332	/* cpuinfo and default policy values */
1da177e4 LT	333	policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
	334	policy->cur = speed;
	335
	336	result = cpufreq_frequency_table_cpuinfo(policy, speedstep_freqs);
	337	if (result)
bbfebd66	338	return result;
1da177e4	339
32ee8c3e	340	cpufreq_frequency_table_get_attr(speedstep_freqs, policy->cpu);
1da177e4 LT	341
	342	return 0;
	343	}
	344
	345	static int speedstep_cpu_exit(struct cpufreq_policy *policy)
	346	{
	347	cpufreq_frequency_table_put_attr(policy->cpu);
	348	return 0;
	349	}
	350
	351	static unsigned int speedstep_get(unsigned int cpu)
	352	{
	353	if (cpu)
	354	return -ENODEV;
bbfebd66	355	return speedstep_get_frequency(speedstep_processor);
1da177e4 LT	356	}
	357
	358
	359	static int speedstep_resume(struct cpufreq_policy *policy)
	360	{
	361	int result = speedstep_smi_ownership();
	362
	363	if (result)
	364	dprintk("fails in re-aquiring ownership of a SMI interface.\n");
	365
	366	return result;
	367	}
	368
bbfebd66	369	static struct freq_attr *speedstep_attr[] = {
1da177e4 LT	370	&cpufreq_freq_attr_scaling_available_freqs,
	371	NULL,
	372	};
	373
221dee28	374	static struct cpufreq_driver speedstep_driver = {
1da177e4	375	.name = "speedstep-smi",
32ee8c3e DJ	376	.verify = speedstep_verify,
32ee8c3e DJ	377	.target = speedstep_target,
1da177e4 LT	378	.init = speedstep_cpu_init,
	379	.exit = speedstep_cpu_exit,
	380	.get = speedstep_get,
	381	.resume = speedstep_resume,
	382	.owner = THIS_MODULE,
	383	.attr = speedstep_attr,
	384	};
	385
	386	/**
	387	* speedstep_init - initializes the SpeedStep CPUFreq driver
	388	*
	389	* Initializes the SpeedStep support. Returns -ENODEV on unsupported
	390	* BIOS, -EINVAL on problems during initiatization, and zero on
	391	* success.
	392	*/
	393	static int __init speedstep_init(void)
	394	{
	395	speedstep_processor = speedstep_detect_processor();
	396
	397	switch (speedstep_processor) {
bbfebd66 DJ	398	case SPEEDSTEP_CPU_PIII_T:
	399	case SPEEDSTEP_CPU_PIII_C:
	400	case SPEEDSTEP_CPU_PIII_C_EARLY:
1da177e4 LT	401	break;
	402	default:
	403	speedstep_processor = 0;
	404	}
	405
	406	if (!speedstep_processor) {
bbfebd66	407	dprintk("No supported Intel CPU detected.\n");
1da177e4 LT	408	return -ENODEV;
	409	}
	410
bbfebd66 DJ	411	dprintk("signature:0x%.8lx, command:0x%.8lx, "
	412	"event:0x%.8lx, perf_level:0x%.8lx.\n",
	413	ist_info.signature, ist_info.command,
	414	ist_info.event, ist_info.perf_level);
1da177e4	415
32ee8c3e	416	/* Error if no IST-SMI BIOS or no PARM
1da177e4	417	sig= 'ISGE' aka 'Intel Speedstep Gate E' */
32ee8c3e	418	if ((ist_info.signature != 0x47534943) && (
1da177e4 LT	419	(smi_port == 0) \|\| (smi_cmd == 0)))
	420	return -ENODEV;
	421
	422	if (smi_sig == 1)
	423	smi_sig = 0x47534943;
	424	else
	425	smi_sig = ist_info.signature;
	426
	427	/* setup smi_port from MODLULE_PARM or BIOS */
32ee8c3e	428	if ((smi_port > 0xff) \|\| (smi_port < 0))
1da177e4	429	return -EINVAL;
32ee8c3e	430	else if (smi_port == 0)
1da177e4	431	smi_port = ist_info.command & 0xff;
1da177e4	432
32ee8c3e	433	if ((smi_cmd > 0xff) \|\| (smi_cmd < 0))
1da177e4	434	return -EINVAL;
32ee8c3e	435	else if (smi_cmd == 0)
1da177e4	436	smi_cmd = (ist_info.command >> 16) & 0xff;
1da177e4 LT	437
	438	return cpufreq_register_driver(&speedstep_driver);
	439	}
	440
	441
	442	/**
	443	* speedstep_exit - unregisters SpeedStep support
	444	*
	445	* Unregisters SpeedStep support.
	446	*/
	447	static void __exit speedstep_exit(void)
	448	{
	449	cpufreq_unregister_driver(&speedstep_driver);
	450	}
	451
bbfebd66 DJ	452	module_param(smi_port, int, 0444);
	453	module_param(smi_cmd, int, 0444);
	454	module_param(smi_sig, uint, 0444);
1da177e4	455
bbfebd66 DJ	456	MODULE_PARM_DESC(smi_port, "Override the BIOS-given IST port with this value "
	457	"-- Intel's default setting is 0xb2");
	458	MODULE_PARM_DESC(smi_cmd, "Override the BIOS-given IST command with this value "
	459	"-- Intel's default setting is 0x82");
	460	MODULE_PARM_DESC(smi_sig, "Set to 1 to fake the IST signature when using the "
	461	"SMI interface.");
1da177e4	462
bbfebd66 DJ	463	MODULE_AUTHOR("Hiroshi Miura");
	464	MODULE_DESCRIPTION("Speedstep driver for IST applet SMI interface.");
	465	MODULE_LICENSE("GPL");
1da177e4 LT	466
	467	module_init(speedstep_init);
	468	module_exit(speedstep_exit);