[GitHub/LineageOS/android_kernel_samsung_universal7580.git] / drivers / cpufreq / speedstep-smi.c

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


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

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

#include "speedstep-lib.h"

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

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

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

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

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

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

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

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

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

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

	return result;
}

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

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

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

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

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

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

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

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

	return result;
}

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

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

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

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

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

	return state & 1;
}


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

	if (state > 0x1)
		return;

	/* Disable IRQs */
	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
		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;

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

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

	return 0;
}


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


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

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

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

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

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

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

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

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

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

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

	cpufreq_frequency_table_get_attr(speedstep_freqs, policy->cpu);

	return 0;
}

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

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


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

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

	return result;
}

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

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

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

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

	speedstep_processor = speedstep_detect_processor();

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

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

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

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

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

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

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

	return cpufreq_register_driver(&speedstep_driver);
}


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

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

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

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

module_init(speedstep_init);
module_exit(speedstep_exit);
Commit	Line	Data
1da177e4 LT	1	/*
	2	* Intel SpeedStep SMI driver.
	3	*
	4	* (C) 2003 Hiroshi Miura <miura@da-cha.org>
	5	*
	6	* Licensed under the terms of the GNU GPL License version 2.
	7	*
	8	*/
	9
	10
	11	/*********************************************************************
	12	* SPEEDSTEP - DEFINITIONS *
	13	*********************************************************************/
	14
	15	#include <linux/kernel.h>
32ee8c3e DJ	16	#include <linux/module.h>
32ee8c3e DJ	17	#include <linux/moduleparam.h>
1da177e4 LT	18	#include <linux/init.h>
1da177e4 LT	19	#include <linux/cpufreq.h>
1da177e4	20	#include <linux/delay.h>
bbfebd66	21	#include <linux/io.h>
1da177e4	22	#include <asm/ist.h>
fa8031ae	23	#include <asm/cpu_device_id.h>
1da177e4 LT	24
	25	#include "speedstep-lib.h"
	26
	27	/* speedstep system management interface port/command.
	28	*
	29	* These parameters are got from IST-SMI BIOS call.
	30	* If user gives it, these are used.
32ee8c3e	31	*
1da177e4	32	*/
bbfebd66 DJ	33	static int smi_port;
	34	static int smi_cmd;
	35	static unsigned int smi_sig;
1da177e4 LT	36
1da177e4 LT	37	/* info about the processor */
1cce76c2	38	static enum speedstep_processor speedstep_processor;
1da177e4	39
32ee8c3e DJ	40	/*
32ee8c3e DJ	41	* There are only two frequency states for each processor. Values
1da177e4 LT	42	* are in kHz for the time being.
	43	*/
	44	static struct cpufreq_frequency_table speedstep_freqs[] = {
32ee8c3e	45	{SPEEDSTEP_HIGH, 0},
1da177e4 LT	46	{SPEEDSTEP_LOW, 0},
	47	{0, CPUFREQ_TABLE_END},
	48	};
	49
	50	#define GET_SPEEDSTEP_OWNER 0
	51	#define GET_SPEEDSTEP_STATE 1
	52	#define SET_SPEEDSTEP_STATE 2
	53	#define GET_SPEEDSTEP_FREQS 4
	54
	55	/* how often shall the SMI call be tried if it failed, e.g. because
	56	* of DMA activity going on? */
	57	#define SMI_TRIES 5
	58
1da177e4 LT	59	/**
	60	* speedstep_smi_ownership
	61	*/
bbfebd66	62	static int speedstep_smi_ownership(void)
1da177e4	63	{
c6e8256a	64	u32 command, result, magic, dummy;
1da177e4 LT	65	u32 function = GET_SPEEDSTEP_OWNER;
	66	unsigned char magic_data[] = "Copyright (c) 1999 Intel Corporation";
	67
	68	command = (smi_sig & 0xffffff00) \| (smi_cmd & 0xff);
	69	magic = virt_to_phys(magic_data);
	70
2d06d8c4	71	pr_debug("trying to obtain ownership with command %x at port %x\n",
bbfebd66	72	command, smi_port);
1da177e4 LT	73
1da177e4 LT	74	__asm__ __volatile__(
c6e8256a	75	"push %%ebp\n"
1da177e4	76	"out %%al, (%%dx)\n"
c6e8256a	77	"pop %%ebp\n"
bbfebd66 DJ	78	: "=D" (result),
	79	"=a" (dummy), "=b" (dummy), "=c" (dummy), "=d" (dummy),
	80	"=S" (dummy)
f081a529	81	: "a" (command), "b" (function), "c" (0), "d" (smi_port),
bbfebd66	82	"D" (0), "S" (magic)
f081a529	83	: "memory"
1da177e4 LT	84	);
1da177e4 LT	85
2d06d8c4	86	pr_debug("result is %x\n", result);
1da177e4 LT	87
	88	return result;
	89	}
	90
	91	/**
	92	* speedstep_smi_get_freqs - get SpeedStep preferred & current freq.
	93	* @low: the low frequency value is placed here
	94	* @high: the high frequency value is placed here
	95	*
	96	* Only available on later SpeedStep-enabled systems, returns false results or
	97	* even hangs [cf. bugme.osdl.org # 1422] on earlier systems. Empirical testing
	98	* shows that the latter occurs if !(ist_info.event & 0xFFFF).
	99	*/
bbfebd66	100	static int speedstep_smi_get_freqs(unsigned int low, unsigned int high)
1da177e4	101	{
c6e8256a	102	u32 command, result = 0, edi, high_mhz, low_mhz, dummy;
bbfebd66	103	u32 state = 0;
1da177e4 LT	104	u32 function = GET_SPEEDSTEP_FREQS;
	105
	106	if (!(ist_info.event & 0xFFFF)) {
2d06d8c4	107	pr_debug("bug #1422 -- can't read freqs from BIOS\n");
1da177e4 LT	108	return -ENODEV;
	109	}
	110
	111	command = (smi_sig & 0xffffff00) \| (smi_cmd & 0xff);
	112
2d06d8c4	113	pr_debug("trying to determine frequencies with command %x at port %x\n",
bbfebd66	114	command, smi_port);
1da177e4	115
c6e8256a SD	116	__asm__ __volatile__(
c6e8256a SD	117	"push %%ebp\n"
1da177e4	118	"out %%al, (%%dx)\n"
c6e8256a	119	"pop %%ebp"
bbfebd66 DJ	120	: "=a" (result),
	121	"=b" (high_mhz),
	122	"=c" (low_mhz),
	123	"=d" (state), "=D" (edi), "=S" (dummy)
	124	: "a" (command),
	125	"b" (function),
	126	"c" (state),
	127	"d" (smi_port), "S" (0), "D" (0)
1da177e4 LT	128	);
1da177e4 LT	129
2d06d8c4	130	pr_debug("result %x, low_freq %u, high_freq %u\n",
bbfebd66	131	result, low_mhz, high_mhz);
1da177e4 LT	132
	133	/* abort if results are obviously incorrect... */
	134	if ((high_mhz + low_mhz) < 600)
	135	return -EINVAL;
	136
	137	high = high_mhz 1000;
	138	low = low_mhz 1000;
	139
	140	return result;
32ee8c3e	141	}
1da177e4 LT	142
	143	/**
	144	* speedstep_get_state - set the SpeedStep state
	145	* @state: processor frequency state (SPEEDSTEP_LOW or SPEEDSTEP_HIGH)
	146	*
	147	*/
bbfebd66	148	static int speedstep_get_state(void)
1da177e4	149	{
bbfebd66	150	u32 function = GET_SPEEDSTEP_STATE;
c6e8256a	151	u32 result, state, edi, command, dummy;
1da177e4 LT	152
	153	command = (smi_sig & 0xffffff00) \| (smi_cmd & 0xff);
	154
2d06d8c4	155	pr_debug("trying to determine current setting with command %x "
bbfebd66	156	"at port %x\n", command, smi_port);
1da177e4	157
c6e8256a SD	158	__asm__ __volatile__(
c6e8256a SD	159	"push %%ebp\n"
1da177e4	160	"out %%al, (%%dx)\n"
c6e8256a	161	"pop %%ebp\n"
bbfebd66 DJ	162	: "=a" (result),
	163	"=b" (state), "=D" (edi),
	164	"=c" (dummy), "=d" (dummy), "=S" (dummy)
	165	: "a" (command), "b" (function), "c" (0),
	166	"d" (smi_port), "S" (0), "D" (0)
1da177e4 LT	167	);
1da177e4 LT	168
2d06d8c4	169	pr_debug("state is %x, result is %x\n", state, result);
1da177e4	170
bbfebd66	171	return state & 1;
1da177e4 LT	172	}
	173
	174
	175	/**
	176	* speedstep_set_state - set the SpeedStep state
	177	* @state: new processor frequency state (SPEEDSTEP_LOW or SPEEDSTEP_HIGH)
	178	*
	179	*/
bbfebd66	180	static void speedstep_set_state(unsigned int state)
1da177e4	181	{
c6e8256a	182	unsigned int result = 0, command, new_state, dummy;
1da177e4	183	unsigned long flags;
bbfebd66	184	unsigned int function = SET_SPEEDSTEP_STATE;
1da177e4 LT	185	unsigned int retry = 0;
	186
	187	if (state > 0x1)
	188	return;
	189
	190	/* Disable IRQs */
8dd242cd	191	preempt_disable();
1da177e4 LT	192	local_irq_save(flags);
	193
	194	command = (smi_sig & 0xffffff00) \| (smi_cmd & 0xff);
	195
2d06d8c4	196	pr_debug("trying to set frequency to state %u "
bbfebd66 DJ	197	"with command %x at port %x\n",
bbfebd66 DJ	198	state, command, smi_port);
1da177e4 LT	199
	200	do {
	201	if (retry) {
8dd242cd MP	202	/*
	203	* We need to enable interrupts, otherwise the blockage
	204	* won't resolve.
	205	*
	206	* We disable preemption so that other processes don't
	207	* run. If other processes were running, they could
	208	* submit more DMA requests, making the blockage worse.
	209	*/
2d06d8c4	210	pr_debug("retry %u, previous result %u, waiting...\n",
bbfebd66	211	retry, result);
8dd242cd	212	local_irq_enable();
1da177e4	213	mdelay(retry * 50);
8dd242cd	214	local_irq_disable();
1da177e4 LT	215	}
	216	retry++;
	217	__asm__ __volatile__(
c6e8256a	218	"push %%ebp\n"
1da177e4	219	"out %%al, (%%dx)\n"
c6e8256a	220	"pop %%ebp"
bbfebd66 DJ	221	: "=b" (new_state), "=D" (result),
	222	"=c" (dummy), "=a" (dummy),
	223	"=d" (dummy), "=S" (dummy)
	224	: "a" (command), "b" (function), "c" (state),
	225	"d" (smi_port), "S" (0), "D" (0)
1da177e4 LT	226	);
	227	} while ((new_state != state) && (retry <= SMI_TRIES));
	228
	229	/* enable IRQs */
	230	local_irq_restore(flags);
8dd242cd	231	preempt_enable();
1da177e4	232
bbfebd66	233	if (new_state == state)
2d06d8c4	234	pr_debug("change to %u MHz succeeded after %u tries "
bbfebd66 DJ	235	"with result %u\n",
	236	(speedstep_freqs[new_state].frequency / 1000),
	237	retry, result);
	238	else
	239	printk(KERN_ERR "cpufreq: change to state %u "
	240	"failed with new_state %u and result %u\n",
	241	state, new_state, result);
1da177e4 LT	242
	243	return;
	244	}
	245
	246
	247	/**
	248	* speedstep_target - set a new CPUFreq policy
	249	* @policy: new policy
	250	* @target_freq: new freq
32ee8c3e	251	* @relation:
1da177e4 LT	252	*
	253	* Sets a new CPUFreq policy/freq.
	254	*/
bbfebd66	255	static int speedstep_target(struct cpufreq_policy *policy,
1da177e4 LT	256	unsigned int target_freq, unsigned int relation)
	257	{
	258	unsigned int newstate = 0;
	259	struct cpufreq_freqs freqs;
	260
bbfebd66 DJ	261	if (cpufreq_frequency_table_target(policy, &speedstep_freqs[0],
bbfebd66 DJ	262	target_freq, relation, &newstate))
1da177e4 LT	263	return -EINVAL;
	264
	265	freqs.old = speedstep_freqs[speedstep_get_state()].frequency;
	266	freqs.new = speedstep_freqs[newstate].frequency;
1da177e4 LT	267
	268	if (freqs.old == freqs.new)
	269	return 0;
	270
b43a7ffb	271	cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);
1da177e4	272	speedstep_set_state(newstate);
b43a7ffb	273	cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);
1da177e4 LT	274
	275	return 0;
	276	}
	277
	278
	279	/**
	280	* speedstep_verify - verifies a new CPUFreq policy
	281	* @policy: new policy
	282	*
	283	* Limit must be within speedstep_low_freq and speedstep_high_freq, with
	284	* at least one border included.
	285	*/
bbfebd66	286	static int speedstep_verify(struct cpufreq_policy *policy)
1da177e4 LT	287	{
	288	return cpufreq_frequency_table_verify(policy, &speedstep_freqs[0]);
	289	}
	290
	291
	292	static int speedstep_cpu_init(struct cpufreq_policy *policy)
	293	{
	294	int result;
bbfebd66 DJ	295	unsigned int speed, state;
bbfebd66 DJ	296	unsigned int low, high;
1da177e4 LT	297
	298	/* capability check */
	299	if (policy->cpu != 0)
	300	return -ENODEV;
	301
	302	result = speedstep_smi_ownership();
	303	if (result) {
2d06d8c4	304	pr_debug("fails in acquiring ownership of a SMI interface.\n");
1da177e4 LT	305	return -EINVAL;
	306	}
	307
	308	/* detect low and high frequency */
bbfebd66 DJ	309	low = &speedstep_freqs[SPEEDSTEP_LOW].frequency;
	310	high = &speedstep_freqs[SPEEDSTEP_HIGH].frequency;
	311
	312	result = speedstep_smi_get_freqs(low, high);
1da177e4	313	if (result) {
bbfebd66 DJ	314	/* fall back to speedstep_lib.c dection mechanism:
bbfebd66 DJ	315	* try both states out */
2d06d8c4	316	pr_debug("could not detect low and high frequencies "
bbfebd66	317	"by SMI call.\n");
1da177e4	318	result = speedstep_get_freqs(speedstep_processor,
bbfebd66	319	low, high,
1a10760c	320	NULL,
1da177e4 LT	321	&speedstep_set_state);
	322
	323	if (result) {
2d06d8c4	324	pr_debug("could not detect two different speeds"
bbfebd66	325	" -- aborting.\n");
1da177e4 LT	326	return result;
1da177e4 LT	327	} else
2d06d8c4	328	pr_debug("workaround worked.\n");
1da177e4 LT	329	}
	330
	331	/* get current speed setting */
	332	state = speedstep_get_state();
	333	speed = speedstep_freqs[state].frequency;
	334
2d06d8c4	335	pr_debug("currently at %s speed setting - %i MHz\n",
bbfebd66 DJ	336	(speed == speedstep_freqs[SPEEDSTEP_LOW].frequency)
bbfebd66 DJ	337	? "low" : "high",
1da177e4 LT	338	(speed / 1000));
	339
	340	/* cpuinfo and default policy values */
1da177e4 LT	341	policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
	342	policy->cur = speed;
	343
	344	result = cpufreq_frequency_table_cpuinfo(policy, speedstep_freqs);
	345	if (result)
bbfebd66	346	return result;
1da177e4	347
32ee8c3e	348	cpufreq_frequency_table_get_attr(speedstep_freqs, policy->cpu);
1da177e4 LT	349
	350	return 0;
	351	}
	352
	353	static int speedstep_cpu_exit(struct cpufreq_policy *policy)
	354	{
	355	cpufreq_frequency_table_put_attr(policy->cpu);
	356	return 0;
	357	}
	358
	359	static unsigned int speedstep_get(unsigned int cpu)
	360	{
	361	if (cpu)
	362	return -ENODEV;
bbfebd66	363	return speedstep_get_frequency(speedstep_processor);
1da177e4 LT	364	}
	365
	366
	367	static int speedstep_resume(struct cpufreq_policy *policy)
	368	{
	369	int result = speedstep_smi_ownership();
	370
	371	if (result)
2d06d8c4	372	pr_debug("fails in re-acquiring ownership of a SMI interface.\n");
1da177e4 LT	373
	374	return result;
	375	}
	376
bbfebd66	377	static struct freq_attr *speedstep_attr[] = {
1da177e4 LT	378	&cpufreq_freq_attr_scaling_available_freqs,
	379	NULL,
	380	};
	381
221dee28	382	static struct cpufreq_driver speedstep_driver = {
1da177e4	383	.name = "speedstep-smi",
32ee8c3e DJ	384	.verify = speedstep_verify,
32ee8c3e DJ	385	.target = speedstep_target,
1da177e4 LT	386	.init = speedstep_cpu_init,
	387	.exit = speedstep_cpu_exit,
	388	.get = speedstep_get,
	389	.resume = speedstep_resume,
	390	.owner = THIS_MODULE,
	391	.attr = speedstep_attr,
	392	};
	393
fa8031ae AK	394	static const struct x86_cpu_id ss_smi_ids[] = {
	395	{ X86_VENDOR_INTEL, 6, 0xb, },
	396	{ X86_VENDOR_INTEL, 6, 0x8, },
	397	{ X86_VENDOR_INTEL, 15, 2 },
	398	{}
	399	};
	400	#if 0
	401	/* Not auto loaded currently */
	402	MODULE_DEVICE_TABLE(x86cpu, ss_smi_ids);
	403	#endif
	404
1da177e4 LT	405	/**
	406	* speedstep_init - initializes the SpeedStep CPUFreq driver
	407	*
	408	* Initializes the SpeedStep support. Returns -ENODEV on unsupported
	409	* BIOS, -EINVAL on problems during initiatization, and zero on
	410	* success.
	411	*/
	412	static int __init speedstep_init(void)
	413	{
fa8031ae AK	414	if (!x86_match_cpu(ss_smi_ids))
	415	return -ENODEV;
	416
1da177e4 LT	417	speedstep_processor = speedstep_detect_processor();
	418
	419	switch (speedstep_processor) {
bbfebd66 DJ	420	case SPEEDSTEP_CPU_PIII_T:
	421	case SPEEDSTEP_CPU_PIII_C:
	422	case SPEEDSTEP_CPU_PIII_C_EARLY:
1da177e4 LT	423	break;
	424	default:
	425	speedstep_processor = 0;
	426	}
	427
	428	if (!speedstep_processor) {
2d06d8c4	429	pr_debug("No supported Intel CPU detected.\n");
1da177e4 LT	430	return -ENODEV;
	431	}
	432
2d06d8c4 DB	433	pr_debug("signature:0x%.8ulx, command:0x%.8ulx, "
2d06d8c4 DB	434	"event:0x%.8ulx, perf_level:0x%.8ulx.\n",
bbfebd66 DJ	435	ist_info.signature, ist_info.command,
bbfebd66 DJ	436	ist_info.event, ist_info.perf_level);
1da177e4	437
32ee8c3e	438	/* Error if no IST-SMI BIOS or no PARM
1da177e4	439	sig= 'ISGE' aka 'Intel Speedstep Gate E' */
32ee8c3e	440	if ((ist_info.signature != 0x47534943) && (
1da177e4 LT	441	(smi_port == 0) \|\| (smi_cmd == 0)))
	442	return -ENODEV;
	443
	444	if (smi_sig == 1)
	445	smi_sig = 0x47534943;
	446	else
	447	smi_sig = ist_info.signature;
	448
	449	/* setup smi_port from MODLULE_PARM or BIOS */
32ee8c3e	450	if ((smi_port > 0xff) \|\| (smi_port < 0))
1da177e4	451	return -EINVAL;
32ee8c3e	452	else if (smi_port == 0)
1da177e4	453	smi_port = ist_info.command & 0xff;
1da177e4	454
32ee8c3e	455	if ((smi_cmd > 0xff) \|\| (smi_cmd < 0))
1da177e4	456	return -EINVAL;
32ee8c3e	457	else if (smi_cmd == 0)
1da177e4	458	smi_cmd = (ist_info.command >> 16) & 0xff;
1da177e4 LT	459
	460	return cpufreq_register_driver(&speedstep_driver);
	461	}
	462
	463
	464	/**
	465	* speedstep_exit - unregisters SpeedStep support
	466	*
	467	* Unregisters SpeedStep support.
	468	*/
	469	static void __exit speedstep_exit(void)
	470	{
	471	cpufreq_unregister_driver(&speedstep_driver);
	472	}
	473
bbfebd66 DJ	474	module_param(smi_port, int, 0444);
	475	module_param(smi_cmd, int, 0444);
	476	module_param(smi_sig, uint, 0444);
1da177e4	477
bbfebd66 DJ	478	MODULE_PARM_DESC(smi_port, "Override the BIOS-given IST port with this value "
	479	"-- Intel's default setting is 0xb2");
	480	MODULE_PARM_DESC(smi_cmd, "Override the BIOS-given IST command with this value "
	481	"-- Intel's default setting is 0x82");
	482	MODULE_PARM_DESC(smi_sig, "Set to 1 to fake the IST signature when using the "
	483	"SMI interface.");
1da177e4	484
bbfebd66 DJ	485	MODULE_AUTHOR("Hiroshi Miura");
	486	MODULE_DESCRIPTION("Speedstep driver for IST applet SMI interface.");
	487	MODULE_LICENSE("GPL");
1da177e4 LT	488
	489	module_init(speedstep_init);
	490	module_exit(speedstep_exit);