[mirror_ubuntu-artful-kernel.git] / drivers / cpufreq / speedstep-lib.c

/*
 * (C) 2002 - 2003 Dominik Brodowski <linux@brodo.de>
 *
 *  Licensed under the terms of the GNU GPL License version 2.
 *
 *  Library for common functions for Intel SpeedStep v.1 and v.2 support
 *
 *  BIG FAT DISCLAIMER: Work in progress code. Possibly *dangerous*
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/init.h>
#include <linux/cpufreq.h>

#include <asm/msr.h>
#include <asm/tsc.h>
#include "speedstep-lib.h"

#define PFX "speedstep-lib: "

#ifdef CONFIG_X86_SPEEDSTEP_RELAXED_CAP_CHECK
static int relaxed_check;
#else
#define relaxed_check 0
#endif

/*********************************************************************
 *                   GET PROCESSOR CORE SPEED IN KHZ                 *
 *********************************************************************/

static unsigned int pentium3_get_frequency(enum speedstep_processor processor)
{
	/* See table 14 of p3_ds.pdf and table 22 of 29834003.pdf */
	struct {
		unsigned int ratio;	/* Frequency Multiplier (x10) */
		u8 bitmap;		/* power on configuration bits
					[27, 25:22] (in MSR 0x2a) */
	} msr_decode_mult[] = {
		{ 30, 0x01 },
		{ 35, 0x05 },
		{ 40, 0x02 },
		{ 45, 0x06 },
		{ 50, 0x00 },
		{ 55, 0x04 },
		{ 60, 0x0b },
		{ 65, 0x0f },
		{ 70, 0x09 },
		{ 75, 0x0d },
		{ 80, 0x0a },
		{ 85, 0x26 },
		{ 90, 0x20 },
		{ 100, 0x2b },
		{ 0, 0xff }	/* error or unknown value */
	};

	/* PIII(-M) FSB settings: see table b1-b of 24547206.pdf */
	struct {
		unsigned int value;	/* Front Side Bus speed in MHz */
		u8 bitmap;		/* power on configuration bits [18: 19]
					(in MSR 0x2a) */
	} msr_decode_fsb[] = {
		{  66, 0x0 },
		{ 100, 0x2 },
		{ 133, 0x1 },
		{   0, 0xff}
	};

	u32 msr_lo, msr_tmp;
	int i = 0, j = 0;

	/* read MSR 0x2a - we only need the low 32 bits */
	rdmsr(MSR_IA32_EBL_CR_POWERON, msr_lo, msr_tmp);
	pr_debug("P3 - MSR_IA32_EBL_CR_POWERON: 0x%x 0x%x\n", msr_lo, msr_tmp);
	msr_tmp = msr_lo;

	/* decode the FSB */
	msr_tmp &= 0x00c0000;
	msr_tmp >>= 18;
	while (msr_tmp != msr_decode_fsb[i].bitmap) {
		if (msr_decode_fsb[i].bitmap == 0xff)
			return 0;
		i++;
	}

	/* decode the multiplier */
	if (processor == SPEEDSTEP_CPU_PIII_C_EARLY) {
		pr_debug("workaround for early PIIIs\n");
		msr_lo &= 0x03c00000;
	} else
		msr_lo &= 0x0bc00000;
	msr_lo >>= 22;
	while (msr_lo != msr_decode_mult[j].bitmap) {
		if (msr_decode_mult[j].bitmap == 0xff)
			return 0;
		j++;
	}

	pr_debug("speed is %u\n",
		(msr_decode_mult[j].ratio * msr_decode_fsb[i].value * 100));

	return msr_decode_mult[j].ratio * msr_decode_fsb[i].value * 100;
}


static unsigned int pentiumM_get_frequency(void)
{
	u32 msr_lo, msr_tmp;

	rdmsr(MSR_IA32_EBL_CR_POWERON, msr_lo, msr_tmp);
	pr_debug("PM - MSR_IA32_EBL_CR_POWERON: 0x%x 0x%x\n", msr_lo, msr_tmp);

	/* see table B-2 of 24547212.pdf */
	if (msr_lo & 0x00040000) {
		printk(KERN_DEBUG PFX "PM - invalid FSB: 0x%x 0x%x\n",
				msr_lo, msr_tmp);
		return 0;
	}

	msr_tmp = (msr_lo >> 22) & 0x1f;
	pr_debug("bits 22-26 are 0x%x, speed is %u\n",
			msr_tmp, (msr_tmp * 100 * 1000));

	return msr_tmp * 100 * 1000;
}

static unsigned int pentium_core_get_frequency(void)
{
	u32 fsb = 0;
	u32 msr_lo, msr_tmp;
	int ret;

	rdmsr(MSR_FSB_FREQ, msr_lo, msr_tmp);
	/* see table B-2 of 25366920.pdf */
	switch (msr_lo & 0x07) {
	case 5:
		fsb = 100000;
		break;
	case 1:
		fsb = 133333;
		break;
	case 3:
		fsb = 166667;
		break;
	case 2:
		fsb = 200000;
		break;
	case 0:
		fsb = 266667;
		break;
	case 4:
		fsb = 333333;
		break;
	default:
		printk(KERN_ERR "PCORE - MSR_FSB_FREQ undefined value");
	}

	rdmsr(MSR_IA32_EBL_CR_POWERON, msr_lo, msr_tmp);
	pr_debug("PCORE - MSR_IA32_EBL_CR_POWERON: 0x%x 0x%x\n",
			msr_lo, msr_tmp);

	msr_tmp = (msr_lo >> 22) & 0x1f;
	pr_debug("bits 22-26 are 0x%x, speed is %u\n",
			msr_tmp, (msr_tmp * fsb));

	ret = (msr_tmp * fsb);
	return ret;
}


static unsigned int pentium4_get_frequency(void)
{
	struct cpuinfo_x86 *c = &boot_cpu_data;
	u32 msr_lo, msr_hi, mult;
	unsigned int fsb = 0;
	unsigned int ret;
	u8 fsb_code;

	/* Pentium 4 Model 0 and 1 do not have the Core Clock Frequency
	 * to System Bus Frequency Ratio Field in the Processor Frequency
	 * Configuration Register of the MSR. Therefore the current
	 * frequency cannot be calculated and has to be measured.
	 */
	if (c->x86_model < 2)
		return cpu_khz;

	rdmsr(0x2c, msr_lo, msr_hi);

	pr_debug("P4 - MSR_EBC_FREQUENCY_ID: 0x%x 0x%x\n", msr_lo, msr_hi);

	/* decode the FSB: see IA-32 Intel (C) Architecture Software
	 * Developer's Manual, Volume 3: System Prgramming Guide,
	 * revision #12 in Table B-1: MSRs in the Pentium 4 and
	 * Intel Xeon Processors, on page B-4 and B-5.
	 */
	fsb_code = (msr_lo >> 16) & 0x7;
	switch (fsb_code) {
	case 0:
		fsb = 100 * 1000;
		break;
	case 1:
		fsb = 13333 * 10;
		break;
	case 2:
		fsb = 200 * 1000;
		break;
	}

	if (!fsb)
		printk(KERN_DEBUG PFX "couldn't detect FSB speed. "
				"Please send an e-mail to <linux@brodo.de>\n");

	/* Multiplier. */
	mult = msr_lo >> 24;

	pr_debug("P4 - FSB %u kHz; Multiplier %u; Speed %u kHz\n",
			fsb, mult, (fsb * mult));

	ret = (fsb * mult);
	return ret;
}


/* Warning: may get called from smp_call_function_single. */
unsigned int speedstep_get_frequency(enum speedstep_processor processor)
{
	switch (processor) {
	case SPEEDSTEP_CPU_PCORE:
		return pentium_core_get_frequency();
	case SPEEDSTEP_CPU_PM:
		return pentiumM_get_frequency();
	case SPEEDSTEP_CPU_P4D:
	case SPEEDSTEP_CPU_P4M:
		return pentium4_get_frequency();
	case SPEEDSTEP_CPU_PIII_T:
	case SPEEDSTEP_CPU_PIII_C:
	case SPEEDSTEP_CPU_PIII_C_EARLY:
		return pentium3_get_frequency(processor);
	default:
		return 0;
	};
	return 0;
}
EXPORT_SYMBOL_GPL(speedstep_get_frequency);


/*********************************************************************
 *                 DETECT SPEEDSTEP-CAPABLE PROCESSOR                *
 *********************************************************************/

unsigned int speedstep_detect_processor(void)
{
	struct cpuinfo_x86 *c = &cpu_data(0);
	u32 ebx, msr_lo, msr_hi;

	pr_debug("x86: %x, model: %x\n", c->x86, c->x86_model);

	if ((c->x86_vendor != X86_VENDOR_INTEL) ||
	    ((c->x86 != 6) && (c->x86 != 0xF)))
		return 0;

	if (c->x86 == 0xF) {
		/* Intel Mobile Pentium 4-M
		 * or Intel Mobile Pentium 4 with 533 MHz FSB */
		if (c->x86_model != 2)
			return 0;

		ebx = cpuid_ebx(0x00000001);
		ebx &= 0x000000FF;

		pr_debug("ebx value is %x, x86_mask is %x\n", ebx, c->x86_mask);

		switch (c->x86_mask) {
		case 4:
			/*
			 * B-stepping [M-P4-M]
			 * sample has ebx = 0x0f, production has 0x0e.
			 */
			if ((ebx == 0x0e) || (ebx == 0x0f))
				return SPEEDSTEP_CPU_P4M;
			break;
		case 7:
			/*
			 * C-stepping [M-P4-M]
			 * needs to have ebx=0x0e, else it's a celeron:
			 * cf. 25130917.pdf / page 7, footnote 5 even
			 * though 25072120.pdf / page 7 doesn't say
			 * samples are only of B-stepping...
			 */
			if (ebx == 0x0e)
				return SPEEDSTEP_CPU_P4M;
			break;
		case 9:
			/*
			 * D-stepping [M-P4-M or M-P4/533]
			 *
			 * this is totally strange: CPUID 0x0F29 is
			 * used by M-P4-M, M-P4/533 and(!) Celeron CPUs.
			 * The latter need to be sorted out as they don't
			 * support speedstep.
			 * Celerons with CPUID 0x0F29 may have either
			 * ebx=0x8 or 0xf -- 25130917.pdf doesn't say anything
			 * specific.
			 * M-P4-Ms may have either ebx=0xe or 0xf [see above]
			 * M-P4/533 have either ebx=0xe or 0xf. [25317607.pdf]
			 * also, M-P4M HTs have ebx=0x8, too
			 * For now, they are distinguished by the model_id
			 * string
			 */
			if ((ebx == 0x0e) ||
				(strstr(c->x86_model_id,
				    "Mobile Intel(R) Pentium(R) 4") != NULL))
				return SPEEDSTEP_CPU_P4M;
			break;
		default:
			break;
		}
		return 0;
	}

	switch (c->x86_model) {
	case 0x0B: /* Intel PIII [Tualatin] */
		/* cpuid_ebx(1) is 0x04 for desktop PIII,
		 * 0x06 for mobile PIII-M */
		ebx = cpuid_ebx(0x00000001);
		pr_debug("ebx is %x\n", ebx);

		ebx &= 0x000000FF;

		if (ebx != 0x06)
			return 0;

		/* So far all PIII-M processors support SpeedStep. See
		 * Intel's 24540640.pdf of June 2003
		 */
		return SPEEDSTEP_CPU_PIII_T;

	case 0x08: /* Intel PIII [Coppermine] */

		/* all mobile PIII Coppermines have FSB 100 MHz
		 * ==> sort out a few desktop PIIIs. */
		rdmsr(MSR_IA32_EBL_CR_POWERON, msr_lo, msr_hi);
		pr_debug("Coppermine: MSR_IA32_EBL_CR_POWERON is 0x%x, 0x%x\n",
				msr_lo, msr_hi);
		msr_lo &= 0x00c0000;
		if (msr_lo != 0x0080000)
			return 0;

		/*
		 * If the processor is a mobile version,
		 * platform ID has bit 50 set
		 * it has SpeedStep technology if either
		 * bit 56 or 57 is set
		 */
		rdmsr(MSR_IA32_PLATFORM_ID, msr_lo, msr_hi);
		pr_debug("Coppermine: MSR_IA32_PLATFORM ID is 0x%x, 0x%x\n",
				msr_lo, msr_hi);
		if ((msr_hi & (1<<18)) &&
		    (relaxed_check ? 1 : (msr_hi & (3<<24)))) {
			if (c->x86_mask == 0x01) {
				pr_debug("early PIII version\n");
				return SPEEDSTEP_CPU_PIII_C_EARLY;
			} else
				return SPEEDSTEP_CPU_PIII_C;
		}

	default:
		return 0;
	}
}
EXPORT_SYMBOL_GPL(speedstep_detect_processor);


/*********************************************************************
 *                     DETECT SPEEDSTEP SPEEDS                       *
 *********************************************************************/

unsigned int speedstep_get_freqs(enum speedstep_processor processor,
				  unsigned int *low_speed,
				  unsigned int *high_speed,
				  unsigned int *transition_latency,
				  void (*set_state) (unsigned int state))
{
	unsigned int prev_speed;
	unsigned int ret = 0;
	unsigned long flags;
	struct timeval tv1, tv2;

	if ((!processor) || (!low_speed) || (!high_speed) || (!set_state))
		return -EINVAL;

	pr_debug("trying to determine both speeds\n");

	/* get current speed */
	prev_speed = speedstep_get_frequency(processor);
	if (!prev_speed)
		return -EIO;

	pr_debug("previous speed is %u\n", prev_speed);

	local_irq_save(flags);

	/* switch to low state */
	set_state(SPEEDSTEP_LOW);
	*low_speed = speedstep_get_frequency(processor);
	if (!*low_speed) {
		ret = -EIO;
		goto out;
	}

	pr_debug("low speed is %u\n", *low_speed);

	/* start latency measurement */
	if (transition_latency)
		do_gettimeofday(&tv1);

	/* switch to high state */
	set_state(SPEEDSTEP_HIGH);

	/* end latency measurement */
	if (transition_latency)
		do_gettimeofday(&tv2);

	*high_speed = speedstep_get_frequency(processor);
	if (!*high_speed) {
		ret = -EIO;
		goto out;
	}

	pr_debug("high speed is %u\n", *high_speed);

	if (*low_speed == *high_speed) {
		ret = -ENODEV;
		goto out;
	}

	/* switch to previous state, if necessary */
	if (*high_speed != prev_speed)
		set_state(SPEEDSTEP_LOW);

	if (transition_latency) {
		*transition_latency = (tv2.tv_sec - tv1.tv_sec) * USEC_PER_SEC +
			tv2.tv_usec - tv1.tv_usec;
		pr_debug("transition latency is %u uSec\n", *transition_latency);

		/* convert uSec to nSec and add 20% for safety reasons */
		*transition_latency *= 1200;

		/* check if the latency measurement is too high or too low
		 * and set it to a safe value (500uSec) in that case
		 */
		if (*transition_latency > 10000000 ||
		    *transition_latency < 50000) {
			printk(KERN_WARNING PFX "frequency transition "
					"measured seems out of range (%u "
					"nSec), falling back to a safe one of"
					"%u nSec.\n",
					*transition_latency, 500000);
			*transition_latency = 500000;
		}
	}

out:
	local_irq_restore(flags);
	return ret;
}
EXPORT_SYMBOL_GPL(speedstep_get_freqs);

#ifdef CONFIG_X86_SPEEDSTEP_RELAXED_CAP_CHECK
module_param(relaxed_check, int, 0444);
MODULE_PARM_DESC(relaxed_check,
		"Don't do all checks for speedstep capability.");
#endif

MODULE_AUTHOR("Dominik Brodowski <linux@brodo.de>");
MODULE_DESCRIPTION("Library for Intel SpeedStep 1 or 2 cpufreq drivers.");
MODULE_LICENSE("GPL");
Commit	Line	Data
1da177e4 LT	1	/*
	2	* (C) 2002 - 2003 Dominik Brodowski <linux@brodo.de>
	3	*
	4	* Licensed under the terms of the GNU GPL License version 2.
	5	*
	6	* Library for common functions for Intel SpeedStep v.1 and v.2 support
	7	*
	8	* BIG FAT DISCLAIMER: Work in progress code. Possibly dangerous
	9	*/
	10
	11	#include <linux/kernel.h>
32ee8c3e	12	#include <linux/module.h>
1da177e4 LT	13	#include <linux/moduleparam.h>
	14	#include <linux/init.h>
	15	#include <linux/cpufreq.h>
1da177e4 LT	16
1da177e4 LT	17	#include <asm/msr.h>
199785ea	18	#include <asm/tsc.h>
1da177e4 LT	19	#include "speedstep-lib.h"
1da177e4 LT	20
bbfebd66	21	#define PFX "speedstep-lib: "
1da177e4 LT	22
1da177e4 LT	23	#ifdef CONFIG_X86_SPEEDSTEP_RELAXED_CAP_CHECK
bbfebd66	24	static int relaxed_check;
1da177e4 LT	25	#else
	26	#define relaxed_check 0
	27	#endif
	28
	29	/*********************************************************************
	30	* GET PROCESSOR CORE SPEED IN KHZ *
	31	*********************************************************************/
	32
1cce76c2	33	static unsigned int pentium3_get_frequency(enum speedstep_processor processor)
1da177e4	34	{
bbfebd66	35	/* See table 14 of p3_ds.pdf and table 22 of 29834003.pdf */
1da177e4 LT	36	struct {
1da177e4 LT	37	unsigned int ratio; /* Frequency Multiplier (x10) */
32ee8c3e DJ	38	u8 bitmap; /* power on configuration bits
32ee8c3e DJ	39	[27, 25:22] (in MSR 0x2a) */
bbfebd66	40	} msr_decode_mult[] = {
1da177e4 LT	41	{ 30, 0x01 },
	42	{ 35, 0x05 },
	43	{ 40, 0x02 },
	44	{ 45, 0x06 },
	45	{ 50, 0x00 },
	46	{ 55, 0x04 },
	47	{ 60, 0x0b },
	48	{ 65, 0x0f },
	49	{ 70, 0x09 },
	50	{ 75, 0x0d },
	51	{ 80, 0x0a },
	52	{ 85, 0x26 },
	53	{ 90, 0x20 },
	54	{ 100, 0x2b },
bbfebd66	55	{ 0, 0xff } /* error or unknown value */
1da177e4 LT	56	};
	57
	58	/* PIII(-M) FSB settings: see table b1-b of 24547206.pdf */
	59	struct {
32ee8c3e DJ	60	unsigned int value; /* Front Side Bus speed in MHz */
	61	u8 bitmap; /* power on configuration bits [18: 19]
	62	(in MSR 0x2a) */
bbfebd66	63	} msr_decode_fsb[] = {
1da177e4 LT	64	{ 66, 0x0 },
	65	{ 100, 0x2 },
	66	{ 133, 0x1 },
	67	{ 0, 0xff}
	68	};
	69
32ee8c3e DJ	70	u32 msr_lo, msr_tmp;
32ee8c3e DJ	71	int i = 0, j = 0;
1da177e4 LT	72
	73	/* read MSR 0x2a - we only need the low 32 bits */
	74	rdmsr(MSR_IA32_EBL_CR_POWERON, msr_lo, msr_tmp);
2d06d8c4	75	pr_debug("P3 - MSR_IA32_EBL_CR_POWERON: 0x%x 0x%x\n", msr_lo, msr_tmp);
1da177e4 LT	76	msr_tmp = msr_lo;
	77
	78	/* decode the FSB */
	79	msr_tmp &= 0x00c0000;
	80	msr_tmp >>= 18;
	81	while (msr_tmp != msr_decode_fsb[i].bitmap) {
	82	if (msr_decode_fsb[i].bitmap == 0xff)
	83	return 0;
	84	i++;
	85	}
	86
	87	/* decode the multiplier */
bbfebd66	88	if (processor == SPEEDSTEP_CPU_PIII_C_EARLY) {
2d06d8c4	89	pr_debug("workaround for early PIIIs\n");
1da177e4 LT	90	msr_lo &= 0x03c00000;
	91	} else
	92	msr_lo &= 0x0bc00000;
	93	msr_lo >>= 22;
	94	while (msr_lo != msr_decode_mult[j].bitmap) {
	95	if (msr_decode_mult[j].bitmap == 0xff)
	96	return 0;
	97	j++;
	98	}
	99
2d06d8c4	100	pr_debug("speed is %u\n",
bbfebd66	101	(msr_decode_mult[j].ratio * msr_decode_fsb[i].value * 100));
1da177e4	102
bbfebd66	103	return msr_decode_mult[j].ratio * msr_decode_fsb[i].value * 100;
1da177e4 LT	104	}
	105
	106
	107	static unsigned int pentiumM_get_frequency(void)
	108	{
32ee8c3e	109	u32 msr_lo, msr_tmp;
1da177e4 LT	110
1da177e4 LT	111	rdmsr(MSR_IA32_EBL_CR_POWERON, msr_lo, msr_tmp);
2d06d8c4	112	pr_debug("PM - MSR_IA32_EBL_CR_POWERON: 0x%x 0x%x\n", msr_lo, msr_tmp);
1da177e4 LT	113
	114	/* see table B-2 of 24547212.pdf */
	115	if (msr_lo & 0x00040000) {
bbfebd66 DJ	116	printk(KERN_DEBUG PFX "PM - invalid FSB: 0x%x 0x%x\n",
bbfebd66 DJ	117	msr_lo, msr_tmp);
1da177e4 LT	118	return 0;
	119	}
	120
	121	msr_tmp = (msr_lo >> 22) & 0x1f;
2d06d8c4	122	pr_debug("bits 22-26 are 0x%x, speed is %u\n",
bbfebd66	123	msr_tmp, (msr_tmp * 100 * 1000));
1da177e4	124
bbfebd66	125	return msr_tmp * 100 * 1000;
1da177e4 LT	126	}
1da177e4 LT	127
4e74663c DB	128	static unsigned int pentium_core_get_frequency(void)
	129	{
	130	u32 fsb = 0;
	131	u32 msr_lo, msr_tmp;
bbfebd66	132	int ret;
4e74663c DB	133
4e74663c DB	134	rdmsr(MSR_FSB_FREQ, msr_lo, msr_tmp);
e11952b9	135	/* see table B-2 of 25366920.pdf */
4e74663c DB	136	switch (msr_lo & 0x07) {
4e74663c DB	137	case 5:
e11952b9	138	fsb = 100000;
4e74663c DB	139	break;
4e74663c DB	140	case 1:
e11952b9	141	fsb = 133333;
4e74663c DB	142	break;
4e74663c DB	143	case 3:
e11952b9	144	fsb = 166667;
4e74663c	145	break;
c60e19eb HRK	146	case 2:
	147	fsb = 200000;
	148	break;
	149	case 0:
	150	fsb = 266667;
	151	break;
	152	case 4:
	153	fsb = 333333;
	154	break;
4e74663c DB	155	default:
	156	printk(KERN_ERR "PCORE - MSR_FSB_FREQ undefined value");
	157	}
	158
	159	rdmsr(MSR_IA32_EBL_CR_POWERON, msr_lo, msr_tmp);
2d06d8c4	160	pr_debug("PCORE - MSR_IA32_EBL_CR_POWERON: 0x%x 0x%x\n",
bbfebd66	161	msr_lo, msr_tmp);
4e74663c DB	162
4e74663c DB	163	msr_tmp = (msr_lo >> 22) & 0x1f;
2d06d8c4	164	pr_debug("bits 22-26 are 0x%x, speed is %u\n",
bbfebd66	165	msr_tmp, (msr_tmp * fsb));
4e74663c	166
bbfebd66 DJ	167	ret = (msr_tmp * fsb);
bbfebd66 DJ	168	return ret;
4e74663c	169	}
e11952b9	170
1da177e4 LT	171
	172	static unsigned int pentium4_get_frequency(void)
	173	{
	174	struct cpuinfo_x86 *c = &boot_cpu_data;
	175	u32 msr_lo, msr_hi, mult;
	176	unsigned int fsb = 0;
bbfebd66	177	unsigned int ret;
199785ea MCO	178	u8 fsb_code;
	179
	180	/* Pentium 4 Model 0 and 1 do not have the Core Clock Frequency
	181	* to System Bus Frequency Ratio Field in the Processor Frequency
	182	* Configuration Register of the MSR. Therefore the current
	183	* frequency cannot be calculated and has to be measured.
	184	*/
	185	if (c->x86_model < 2)
	186	return cpu_khz;
1da177e4 LT	187
	188	rdmsr(0x2c, msr_lo, msr_hi);
	189
2d06d8c4	190	pr_debug("P4 - MSR_EBC_FREQUENCY_ID: 0x%x 0x%x\n", msr_lo, msr_hi);
1da177e4	191
32ee8c3e	192	/* decode the FSB: see IA-32 Intel (C) Architecture Software
1da177e4 LT	193	* Developer's Manual, Volume 3: System Prgramming Guide,
	194	* revision #12 in Table B-1: MSRs in the Pentium 4 and
	195	* Intel Xeon Processors, on page B-4 and B-5.
	196	*/
199785ea MCO	197	fsb_code = (msr_lo >> 16) & 0x7;
	198	switch (fsb_code) {
	199	case 0:
1da177e4	200	fsb = 100 * 1000;
199785ea MCO	201	break;
	202	case 1:
	203	fsb = 13333 * 10;
	204	break;
	205	case 2:
	206	fsb = 200 * 1000;
	207	break;
1da177e4 LT	208	}
	209
	210	if (!fsb)
bbfebd66 DJ	211	printk(KERN_DEBUG PFX "couldn't detect FSB speed. "
bbfebd66 DJ	212	"Please send an e-mail to <linux@brodo.de>\n");
1da177e4 LT	213
1da177e4 LT	214	/* Multiplier. */
ed9cbcd4	215	mult = msr_lo >> 24;
1da177e4	216
2d06d8c4	217	pr_debug("P4 - FSB %u kHz; Multiplier %u; Speed %u kHz\n",
bbfebd66	218	fsb, mult, (fsb * mult));
1da177e4	219
bbfebd66 DJ	220	ret = (fsb * mult);
bbfebd66 DJ	221	return ret;
1da177e4 LT	222	}
1da177e4 LT	223
32ee8c3e	224
394122ab	225	/* Warning: may get called from smp_call_function_single. */
1cce76c2	226	unsigned int speedstep_get_frequency(enum speedstep_processor processor)
1da177e4 LT	227	{
1da177e4 LT	228	switch (processor) {
bbfebd66	229	case SPEEDSTEP_CPU_PCORE:
4e74663c	230	return pentium_core_get_frequency();
bbfebd66	231	case SPEEDSTEP_CPU_PM:
1da177e4	232	return pentiumM_get_frequency();
bbfebd66 DJ	233	case SPEEDSTEP_CPU_P4D:
bbfebd66 DJ	234	case SPEEDSTEP_CPU_P4M:
1da177e4	235	return pentium4_get_frequency();
bbfebd66 DJ	236	case SPEEDSTEP_CPU_PIII_T:
	237	case SPEEDSTEP_CPU_PIII_C:
	238	case SPEEDSTEP_CPU_PIII_C_EARLY:
1da177e4 LT	239	return pentium3_get_frequency(processor);
	240	default:
	241	return 0;
	242	};
	243	return 0;
	244	}
bbfebd66	245	EXPORT_SYMBOL_GPL(speedstep_get_frequency);
1da177e4 LT	246
	247
	248	/*********************************************************************
	249	* DETECT SPEEDSTEP-CAPABLE PROCESSOR *
	250	*********************************************************************/
	251
bbfebd66	252	unsigned int speedstep_detect_processor(void)
1da177e4	253	{
92cb7612	254	struct cpuinfo_x86 *c = &cpu_data(0);
32ee8c3e	255	u32 ebx, msr_lo, msr_hi;
1da177e4	256
2d06d8c4	257	pr_debug("x86: %x, model: %x\n", c->x86, c->x86_model);
1da177e4	258
32ee8c3e	259	if ((c->x86_vendor != X86_VENDOR_INTEL) \|\|
1da177e4 LT	260	((c->x86 != 6) && (c->x86 != 0xF)))
	261	return 0;
	262
	263	if (c->x86 == 0xF) {
	264	/* Intel Mobile Pentium 4-M
	265	* or Intel Mobile Pentium 4 with 533 MHz FSB */
	266	if (c->x86_model != 2)
	267	return 0;
	268
	269	ebx = cpuid_ebx(0x00000001);
	270	ebx &= 0x000000FF;
	271
2d06d8c4	272	pr_debug("ebx value is %x, x86_mask is %x\n", ebx, c->x86_mask);
1da177e4 LT	273
1da177e4 LT	274	switch (c->x86_mask) {
32ee8c3e	275	case 4:
1da177e4	276	/*
32ee8c3e	277	* B-stepping [M-P4-M]
1da177e4 LT	278	* sample has ebx = 0x0f, production has 0x0e.
	279	*/
	280	if ((ebx == 0x0e) \|\| (ebx == 0x0f))
bbfebd66	281	return SPEEDSTEP_CPU_P4M;
1da177e4	282	break;
32ee8c3e	283	case 7:
1da177e4 LT	284	/*
	285	* C-stepping [M-P4-M]
	286	* needs to have ebx=0x0e, else it's a celeron:
	287	* cf. 25130917.pdf / page 7, footnote 5 even
	288	* though 25072120.pdf / page 7 doesn't say
	289	* samples are only of B-stepping...
	290	*/
	291	if (ebx == 0x0e)
bbfebd66	292	return SPEEDSTEP_CPU_P4M;
1da177e4 LT	293	break;
	294	case 9:
	295	/*
	296	* D-stepping [M-P4-M or M-P4/533]
	297	*
	298	* this is totally strange: CPUID 0x0F29 is
	299	* used by M-P4-M, M-P4/533 and(!) Celeron CPUs.
	300	* The latter need to be sorted out as they don't
	301	* support speedstep.
	302	* Celerons with CPUID 0x0F29 may have either
	303	* ebx=0x8 or 0xf -- 25130917.pdf doesn't say anything
	304	* specific.
	305	* M-P4-Ms may have either ebx=0xe or 0xf [see above]
	306	* M-P4/533 have either ebx=0xe or 0xf. [25317607.pdf]
	307	* also, M-P4M HTs have ebx=0x8, too
bbfebd66 DJ	308	* For now, they are distinguished by the model_id
bbfebd66 DJ	309	* string
1da177e4	310	*/
bbfebd66 DJ	311	if ((ebx == 0x0e) \|\|
	312	(strstr(c->x86_model_id,
	313	"Mobile Intel(R) Pentium(R) 4") != NULL))
	314	return SPEEDSTEP_CPU_P4M;
1da177e4 LT	315	break;
	316	default:
	317	break;
	318	}
	319	return 0;
	320	}
	321
	322	switch (c->x86_model) {
	323	case 0x0B: /* Intel PIII [Tualatin] */
bbfebd66 DJ	324	/* cpuid_ebx(1) is 0x04 for desktop PIII,
bbfebd66 DJ	325	* 0x06 for mobile PIII-M */
1da177e4	326	ebx = cpuid_ebx(0x00000001);
2d06d8c4	327	pr_debug("ebx is %x\n", ebx);
1da177e4 LT	328
	329	ebx &= 0x000000FF;
	330
	331	if (ebx != 0x06)
	332	return 0;
	333
	334	/* So far all PIII-M processors support SpeedStep. See
32ee8c3e	335	* Intel's 24540640.pdf of June 2003
1da177e4	336	*/
bbfebd66	337	return SPEEDSTEP_CPU_PIII_T;
1da177e4 LT	338
	339	case 0x08: /* Intel PIII [Coppermine] */
	340
	341	/* all mobile PIII Coppermines have FSB 100 MHz
	342	* ==> sort out a few desktop PIIIs. */
	343	rdmsr(MSR_IA32_EBL_CR_POWERON, msr_lo, msr_hi);
2d06d8c4	344	pr_debug("Coppermine: MSR_IA32_EBL_CR_POWERON is 0x%x, 0x%x\n",
bbfebd66	345	msr_lo, msr_hi);
1da177e4 LT	346	msr_lo &= 0x00c0000;
	347	if (msr_lo != 0x0080000)
	348	return 0;
	349
	350	/*
	351	* If the processor is a mobile version,
	352	* platform ID has bit 50 set
	353	* it has SpeedStep technology if either
	354	* bit 56 or 57 is set
	355	*/
	356	rdmsr(MSR_IA32_PLATFORM_ID, msr_lo, msr_hi);
2d06d8c4	357	pr_debug("Coppermine: MSR_IA32_PLATFORM ID is 0x%x, 0x%x\n",
bbfebd66 DJ	358	msr_lo, msr_hi);
	359	if ((msr_hi & (1<<18)) &&
	360	(relaxed_check ? 1 : (msr_hi & (3<<24)))) {
1da177e4	361	if (c->x86_mask == 0x01) {
2d06d8c4	362	pr_debug("early PIII version\n");
bbfebd66	363	return SPEEDSTEP_CPU_PIII_C_EARLY;
1da177e4	364	} else
bbfebd66	365	return SPEEDSTEP_CPU_PIII_C;
1da177e4 LT	366	}
	367
	368	default:
	369	return 0;
	370	}
	371	}
	372	EXPORT_SYMBOL_GPL(speedstep_detect_processor);
	373
	374
	375	/*********************************************************************
	376	* DETECT SPEEDSTEP SPEEDS *
	377	*********************************************************************/
	378
1cce76c2	379	unsigned int speedstep_get_freqs(enum speedstep_processor processor,
1da177e4 LT	380	unsigned int *low_speed,
1da177e4 LT	381	unsigned int *high_speed,
1a10760c	382	unsigned int *transition_latency,
1da177e4 LT	383	void (*set_state) (unsigned int state))
	384	{
	385	unsigned int prev_speed;
	386	unsigned int ret = 0;
	387	unsigned long flags;
1a10760c	388	struct timeval tv1, tv2;
1da177e4 LT	389
	390	if ((!processor) \|\| (!low_speed) \|\| (!high_speed) \|\| (!set_state))
	391	return -EINVAL;
	392
2d06d8c4	393	pr_debug("trying to determine both speeds\n");
1da177e4 LT	394
1da177e4 LT	395	/* get current speed */
bbfebd66	396	prev_speed = speedstep_get_frequency(processor);
1da177e4 LT	397	if (!prev_speed)
	398	return -EIO;
	399
2d06d8c4	400	pr_debug("previous speed is %u\n", prev_speed);
1a10760c	401
1da177e4 LT	402	local_irq_save(flags);
	403
	404	/* switch to low state */
	405	set_state(SPEEDSTEP_LOW);
bbfebd66	406	*low_speed = speedstep_get_frequency(processor);
1da177e4 LT	407	if (!*low_speed) {
	408	ret = -EIO;
	409	goto out;
	410	}
	411
2d06d8c4	412	pr_debug("low speed is %u\n", *low_speed);
1da177e4	413
1a10760c MD	414	/* start latency measurement */
	415	if (transition_latency)
	416	do_gettimeofday(&tv1);
	417
1da177e4 LT	418	/* switch to high state */
1da177e4 LT	419	set_state(SPEEDSTEP_HIGH);
1a10760c MD	420
	421	/* end latency measurement */
	422	if (transition_latency)
	423	do_gettimeofday(&tv2);
	424
bbfebd66	425	*high_speed = speedstep_get_frequency(processor);
1da177e4 LT	426	if (!*high_speed) {
	427	ret = -EIO;
	428	goto out;
	429	}
	430
2d06d8c4	431	pr_debug("high speed is %u\n", *high_speed);
1da177e4 LT	432
	433	if (low_speed == high_speed) {
	434	ret = -ENODEV;
	435	goto out;
	436	}
	437
	438	/* switch to previous state, if necessary */
	439	if (*high_speed != prev_speed)
	440	set_state(SPEEDSTEP_LOW);
	441
1a10760c MD	442	if (transition_latency) {
	443	transition_latency = (tv2.tv_sec - tv1.tv_sec) USEC_PER_SEC +
	444	tv2.tv_usec - tv1.tv_usec;
2d06d8c4	445	pr_debug("transition latency is %u uSec\n", *transition_latency);
1a10760c MD	446
	447	/* convert uSec to nSec and add 20% for safety reasons */
	448	transition_latency = 1200;
	449
	450	/* check if the latency measurement is too high or too low
	451	* and set it to a safe value (500uSec) in that case
	452	*/
bbfebd66 DJ	453	if (*transition_latency > 10000000 \|\|
	454	*transition_latency < 50000) {
	455	printk(KERN_WARNING PFX "frequency transition "
	456	"measured seems out of range (%u "
	457	"nSec), falling back to a safe one of"
	458	"%u nSec.\n",
1a10760c MD	459	*transition_latency, 500000);
	460	*transition_latency = 500000;
	461	}
	462	}
	463
32ee8c3e	464	out:
1da177e4	465	local_irq_restore(flags);
bbfebd66	466	return ret;
1da177e4 LT	467	}
	468	EXPORT_SYMBOL_GPL(speedstep_get_freqs);
	469
	470	#ifdef CONFIG_X86_SPEEDSTEP_RELAXED_CAP_CHECK
	471	module_param(relaxed_check, int, 0444);
bbfebd66 DJ	472	MODULE_PARM_DESC(relaxed_check,
bbfebd66 DJ	473	"Don't do all checks for speedstep capability.");
1da177e4 LT	474	#endif
1da177e4 LT	475
bbfebd66 DJ	476	MODULE_AUTHOR("Dominik Brodowski <linux@brodo.de>");
	477	MODULE_DESCRIPTION("Library for Intel SpeedStep 1 or 2 cpufreq drivers.");
	478	MODULE_LICENSE("GPL");