drivers/cpufreq/speedstep-lib.c - linux/kernel/git/bpf/bpf - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * (C) 2002 - 2003 Dominik Brodowski <linux@brodo.de>
  *
  *  Library for common functions for Intel SpeedStep v.1 and v.2 support
  *
  *  BIG FAT DISCLAIMER: Work in progress code. Possibly *dangerous*
  */

 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

 #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 */
 	static const 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 */
 	static const 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:
 		pr_err("PCORE - MSR_FSB_FREQ undefined value\n");
 	}

 	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                *
  *********************************************************************/

 /* Keep in sync with the x86_cpu_id tables in the different modules */
 enum speedstep_processor 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_stepping is %x\n", ebx, c->x86_stepping);

 		switch (c->x86_stepping) {
 		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_stepping == 0x01) {
 				pr_debug("early PIII version\n");
 				return SPEEDSTEP_CPU_PIII_C_EARLY;
 			} else
 				return SPEEDSTEP_CPU_PIII_C;
 		}
 		fallthrough;
 	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;
 	ktime_t 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);

 	preempt_disable();
 	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)
 		tv1 = ktime_get();

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

 	/* end latency measurement */
 	if (transition_latency)
 		tv2 = ktime_get();

 	*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 = ktime_to_us(ktime_sub(tv2, tv1));
 		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) {
 			pr_warn("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);
 	preempt_enable();

 	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");
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* (C) 2002 - 2003 Dominik Brodowski <linux@brodo.de>
	*
	* Library for common functions for Intel SpeedStep v.1 and v.2 support
	*
	* BIG FAT DISCLAIMER: Work in progress code. Possibly dangerous
	*/

	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

	#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 */
	static const 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 */
	static const 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:
	pr_err("PCORE - MSR_FSB_FREQ undefined value\n");
	}

	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 *
	*********************************************************************/

	/* Keep in sync with the x86_cpu_id tables in the different modules */
	enum speedstep_processor 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_stepping is %x\n", ebx, c->x86_stepping);

	switch (c->x86_stepping) {
	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_stepping == 0x01) {
	pr_debug("early PIII version\n");
	return SPEEDSTEP_CPU_PIII_C_EARLY;
	} else
	return SPEEDSTEP_CPU_PIII_C;
	}
	fallthrough;
	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;
	ktime_t 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);

	preempt_disable();
	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)
	tv1 = ktime_get();

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

	/* end latency measurement */
	if (transition_latency)
	tv2 = ktime_get();

	*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 = ktime_to_us(ktime_sub(tv2, tv1));
	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) {
	pr_warn("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);
	preempt_enable();

	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");