drivers/cpufreq/p4-clockmod.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-or-later
 /*
  *	Pentium 4/Xeon CPU on demand clock modulation/speed scaling
  *	(C) 2002 - 2003 Dominik Brodowski <linux@brodo.de>
  *	(C) 2002 Zwane Mwaikambo <zwane@commfireservices.com>
  *	(C) 2002 Arjan van de Ven <arjanv@redhat.com>
  *	(C) 2002 Tora T. Engstad
  *	All Rights Reserved
  *
  *      The author(s) of this software shall not be held liable for damages
  *      of any nature resulting due to the use of this software. This
  *      software is provided AS-IS with no warranties.
  *
  *	Date		Errata			Description
  *	20020525	N44, O17	12.5% or 25% DC causes lockup
  */

 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/smp.h>
 #include <linux/cpufreq.h>
 #include <linux/cpumask.h>
 #include <linux/timex.h>

 #include <asm/processor.h>
 #include <asm/msr.h>
 #include <asm/timer.h>
 #include <asm/cpu_device_id.h>

 #include "speedstep-lib.h"

 /*
  * Duty Cycle (3bits), note DC_DISABLE is not specified in
  * intel docs i just use it to mean disable
  */
 enum {
 	DC_RESV, DC_DFLT, DC_25PT, DC_38PT, DC_50PT,
 	DC_64PT, DC_75PT, DC_88PT, DC_DISABLE
 };

 #define DC_ENTRIES	8


 static int has_N44_O17_errata[NR_CPUS];
 static unsigned int stock_freq;
 static struct cpufreq_driver p4clockmod_driver;
 static unsigned int cpufreq_p4_get(unsigned int cpu);

 static int cpufreq_p4_setdc(unsigned int cpu, unsigned int newstate)
 {
 	u32 l, h;

 	if ((newstate > DC_DISABLE) || (newstate == DC_RESV))
 		return -EINVAL;

 	rdmsr_on_cpu(cpu, MSR_IA32_THERM_STATUS, &l, &h);

 	if (l & 0x01)
 		pr_debug("CPU#%d currently thermal throttled\n", cpu);

 	if (has_N44_O17_errata[cpu] &&
 	    (newstate == DC_25PT || newstate == DC_DFLT))
 		newstate = DC_38PT;

 	rdmsr_on_cpu(cpu, MSR_IA32_THERM_CONTROL, &l, &h);
 	if (newstate == DC_DISABLE) {
 		pr_debug("CPU#%d disabling modulation\n", cpu);
 		wrmsr_on_cpu(cpu, MSR_IA32_THERM_CONTROL, l & ~(1<<4), h);
 	} else {
 		pr_debug("CPU#%d setting duty cycle to %d%%\n",
 			cpu, ((125 * newstate) / 10));
 		/* bits 63 - 5	: reserved
 		 * bit  4	: enable/disable
 		 * bits 3-1	: duty cycle
 		 * bit  0	: reserved
 		 */
 		l = (l & ~14);
 		l = l | (1<<4) | ((newstate & 0x7)<<1);
 		wrmsr_on_cpu(cpu, MSR_IA32_THERM_CONTROL, l, h);
 	}

 	return 0;
 }


 static struct cpufreq_frequency_table p4clockmod_table[] = {
 	{0, DC_RESV, CPUFREQ_ENTRY_INVALID},
 	{0, DC_DFLT, 0},
 	{0, DC_25PT, 0},
 	{0, DC_38PT, 0},
 	{0, DC_50PT, 0},
 	{0, DC_64PT, 0},
 	{0, DC_75PT, 0},
 	{0, DC_88PT, 0},
 	{0, DC_DISABLE, 0},
 	{0, DC_RESV, CPUFREQ_TABLE_END},
 };


 static int cpufreq_p4_target(struct cpufreq_policy *policy, unsigned int index)
 {
 	int i;

 	/* run on each logical CPU,
 	 * see section 13.15.3 of IA32 Intel Architecture Software
 	 * Developer's Manual, Volume 3
 	 */
 	for_each_cpu(i, policy->cpus)
 		cpufreq_p4_setdc(i, p4clockmod_table[index].driver_data);

 	return 0;
 }


 static unsigned int cpufreq_p4_get_frequency(struct cpuinfo_x86 *c)
 {
 	if (c->x86 == 0x06) {
 		if (cpu_has(c, X86_FEATURE_EST))
 			pr_warn_once("Warning: EST-capable CPU detected. The acpi-cpufreq module offers voltage scaling in addition to frequency scaling. You should use that instead of p4-clockmod, if possible.\n");
 		switch (c->x86_model) {
 		case 0x0E: /* Core */
 		case 0x0F: /* Core Duo */
 		case 0x16: /* Celeron Core */
 		case 0x1C: /* Atom */
 			p4clockmod_driver.flags |= CPUFREQ_CONST_LOOPS;
 			return speedstep_get_frequency(SPEEDSTEP_CPU_PCORE);
 		case 0x0D: /* Pentium M (Dothan) */
 			p4clockmod_driver.flags |= CPUFREQ_CONST_LOOPS;
 			/* fall through */
 		case 0x09: /* Pentium M (Banias) */
 			return speedstep_get_frequency(SPEEDSTEP_CPU_PM);
 		}
 	}

 	if (c->x86 != 0xF)
 		return 0;

 	/* on P-4s, the TSC runs with constant frequency independent whether
 	 * throttling is active or not. */
 	p4clockmod_driver.flags |= CPUFREQ_CONST_LOOPS;

 	if (speedstep_detect_processor() == SPEEDSTEP_CPU_P4M) {
 		pr_warn("Warning: Pentium 4-M detected. The speedstep-ich or acpi cpufreq modules offer voltage scaling in addition of frequency scaling. You should use either one instead of p4-clockmod, if possible.\n");
 		return speedstep_get_frequency(SPEEDSTEP_CPU_P4M);
 	}

 	return speedstep_get_frequency(SPEEDSTEP_CPU_P4D);
 }


 static int cpufreq_p4_cpu_init(struct cpufreq_policy *policy)
 {
 	struct cpuinfo_x86 *c = &cpu_data(policy->cpu);
 	int cpuid = 0;
 	unsigned int i;

 #ifdef CONFIG_SMP
 	cpumask_copy(policy->cpus, topology_sibling_cpumask(policy->cpu));
 #endif

 	/* Errata workaround */
 	cpuid = (c->x86 << 8) | (c->x86_model << 4) | c->x86_stepping;
 	switch (cpuid) {
 	case 0x0f07:
 	case 0x0f0a:
 	case 0x0f11:
 	case 0x0f12:
 		has_N44_O17_errata[policy->cpu] = 1;
 		pr_debug("has errata -- disabling low frequencies\n");
 	}

 	if (speedstep_detect_processor() == SPEEDSTEP_CPU_P4D &&
 	    c->x86_model < 2) {
 		/* switch to maximum frequency and measure result */
 		cpufreq_p4_setdc(policy->cpu, DC_DISABLE);
 		recalibrate_cpu_khz();
 	}
 	/* get max frequency */
 	stock_freq = cpufreq_p4_get_frequency(c);
 	if (!stock_freq)
 		return -EINVAL;

 	/* table init */
 	for (i = 1; (p4clockmod_table[i].frequency != CPUFREQ_TABLE_END); i++) {
 		if ((i < 2) && (has_N44_O17_errata[policy->cpu]))
 			p4clockmod_table[i].frequency = CPUFREQ_ENTRY_INVALID;
 		else
 			p4clockmod_table[i].frequency = (stock_freq * i)/8;
 	}

 	/* cpuinfo and default policy values */

 	/* the transition latency is set to be 1 higher than the maximum
 	 * transition latency of the ondemand governor */
 	policy->cpuinfo.transition_latency = 10000001;
 	policy->freq_table = &p4clockmod_table[0];

 	return 0;
 }


 static unsigned int cpufreq_p4_get(unsigned int cpu)
 {
 	u32 l, h;

 	rdmsr_on_cpu(cpu, MSR_IA32_THERM_CONTROL, &l, &h);

 	if (l & 0x10) {
 		l = l >> 1;
 		l &= 0x7;
 	} else
 		l = DC_DISABLE;

 	if (l != DC_DISABLE)
 		return stock_freq * l / 8;

 	return stock_freq;
 }

 static struct cpufreq_driver p4clockmod_driver = {
 	.verify		= cpufreq_generic_frequency_table_verify,
 	.target_index	= cpufreq_p4_target,
 	.init		= cpufreq_p4_cpu_init,
 	.get		= cpufreq_p4_get,
 	.name		= "p4-clockmod",
 	.attr		= cpufreq_generic_attr,
 };

 static const struct x86_cpu_id cpufreq_p4_id[] = {
 	{ X86_VENDOR_INTEL, X86_FAMILY_ANY, X86_MODEL_ANY, X86_FEATURE_ACC },
 	{}
 };

 /*
  * Intentionally no MODULE_DEVICE_TABLE here: this driver should not
  * be auto loaded.  Please don't add one.
  */

 static int __init cpufreq_p4_init(void)
 {
 	int ret;

 	/*
 	 * THERM_CONTROL is architectural for IA32 now, so
 	 * we can rely on the capability checks
 	 */
 	if (!x86_match_cpu(cpufreq_p4_id) || !boot_cpu_has(X86_FEATURE_ACPI))
 		return -ENODEV;

 	ret = cpufreq_register_driver(&p4clockmod_driver);
 	if (!ret)
 		pr_info("P4/Xeon(TM) CPU On-Demand Clock Modulation available\n");

 	return ret;
 }


 static void __exit cpufreq_p4_exit(void)
 {
 	cpufreq_unregister_driver(&p4clockmod_driver);
 }


 MODULE_AUTHOR("Zwane Mwaikambo <zwane@commfireservices.com>");
 MODULE_DESCRIPTION("cpufreq driver for Pentium(TM) 4/Xeon(TM)");
 MODULE_LICENSE("GPL");

 late_initcall(cpufreq_p4_init);
 module_exit(cpufreq_p4_exit);
	// SPDX-License-Identifier: GPL-2.0-or-later
	/*
	* Pentium 4/Xeon CPU on demand clock modulation/speed scaling
	* (C) 2002 - 2003 Dominik Brodowski <linux@brodo.de>
	* (C) 2002 Zwane Mwaikambo <zwane@commfireservices.com>
	* (C) 2002 Arjan van de Ven <arjanv@redhat.com>
	* (C) 2002 Tora T. Engstad
	* All Rights Reserved
	*
	* The author(s) of this software shall not be held liable for damages
	* of any nature resulting due to the use of this software. This
	* software is provided AS-IS with no warranties.
	*
	* Date Errata Description
	* 20020525 N44, O17 12.5% or 25% DC causes lockup
	*/

	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/init.h>
	#include <linux/smp.h>
	#include <linux/cpufreq.h>
	#include <linux/cpumask.h>
	#include <linux/timex.h>

	#include <asm/processor.h>
	#include <asm/msr.h>
	#include <asm/timer.h>
	#include <asm/cpu_device_id.h>

	#include "speedstep-lib.h"

	/*
	* Duty Cycle (3bits), note DC_DISABLE is not specified in
	* intel docs i just use it to mean disable
	*/
	enum {
	DC_RESV, DC_DFLT, DC_25PT, DC_38PT, DC_50PT,
	DC_64PT, DC_75PT, DC_88PT, DC_DISABLE
	};

	#define DC_ENTRIES 8


	static int has_N44_O17_errata[NR_CPUS];
	static unsigned int stock_freq;
	static struct cpufreq_driver p4clockmod_driver;
	static unsigned int cpufreq_p4_get(unsigned int cpu);

	static int cpufreq_p4_setdc(unsigned int cpu, unsigned int newstate)
	{
	u32 l, h;

	if ((newstate > DC_DISABLE) \|\| (newstate == DC_RESV))
	return -EINVAL;

	rdmsr_on_cpu(cpu, MSR_IA32_THERM_STATUS, &l, &h);

	if (l & 0x01)
	pr_debug("CPU#%d currently thermal throttled\n", cpu);

	if (has_N44_O17_errata[cpu] &&
	(newstate == DC_25PT \|\| newstate == DC_DFLT))
	newstate = DC_38PT;

	rdmsr_on_cpu(cpu, MSR_IA32_THERM_CONTROL, &l, &h);
	if (newstate == DC_DISABLE) {
	pr_debug("CPU#%d disabling modulation\n", cpu);
	wrmsr_on_cpu(cpu, MSR_IA32_THERM_CONTROL, l & ~(1<<4), h);
	} else {
	pr_debug("CPU#%d setting duty cycle to %d%%\n",
	cpu, ((125 * newstate) / 10));
	/* bits 63 - 5 : reserved
	* bit 4 : enable/disable
	* bits 3-1 : duty cycle
	* bit 0 : reserved
	*/
	l = (l & ~14);
	l = l \| (1<<4) \| ((newstate & 0x7)<<1);
	wrmsr_on_cpu(cpu, MSR_IA32_THERM_CONTROL, l, h);
	}

	return 0;
	}


	static struct cpufreq_frequency_table p4clockmod_table[] = {
	{0, DC_RESV, CPUFREQ_ENTRY_INVALID},
	{0, DC_DFLT, 0},
	{0, DC_25PT, 0},
	{0, DC_38PT, 0},
	{0, DC_50PT, 0},
	{0, DC_64PT, 0},
	{0, DC_75PT, 0},
	{0, DC_88PT, 0},
	{0, DC_DISABLE, 0},
	{0, DC_RESV, CPUFREQ_TABLE_END},
	};


	static int cpufreq_p4_target(struct cpufreq_policy *policy, unsigned int index)
	{
	int i;

	/* run on each logical CPU,
	* see section 13.15.3 of IA32 Intel Architecture Software
	* Developer's Manual, Volume 3
	*/
	for_each_cpu(i, policy->cpus)
	cpufreq_p4_setdc(i, p4clockmod_table[index].driver_data);

	return 0;
	}


	static unsigned int cpufreq_p4_get_frequency(struct cpuinfo_x86 *c)
	{
	if (c->x86 == 0x06) {
	if (cpu_has(c, X86_FEATURE_EST))
	pr_warn_once("Warning: EST-capable CPU detected. The acpi-cpufreq module offers voltage scaling in addition to frequency scaling. You should use that instead of p4-clockmod, if possible.\n");
	switch (c->x86_model) {
	case 0x0E: /* Core */
	case 0x0F: /* Core Duo */
	case 0x16: /* Celeron Core */
	case 0x1C: /* Atom */
	p4clockmod_driver.flags \|= CPUFREQ_CONST_LOOPS;
	return speedstep_get_frequency(SPEEDSTEP_CPU_PCORE);
	case 0x0D: /* Pentium M (Dothan) */
	p4clockmod_driver.flags \|= CPUFREQ_CONST_LOOPS;
	/* fall through */
	case 0x09: /* Pentium M (Banias) */
	return speedstep_get_frequency(SPEEDSTEP_CPU_PM);
	}
	}

	if (c->x86 != 0xF)
	return 0;

	/* on P-4s, the TSC runs with constant frequency independent whether
	* throttling is active or not. */
	p4clockmod_driver.flags \|= CPUFREQ_CONST_LOOPS;

	if (speedstep_detect_processor() == SPEEDSTEP_CPU_P4M) {
	pr_warn("Warning: Pentium 4-M detected. The speedstep-ich or acpi cpufreq modules offer voltage scaling in addition of frequency scaling. You should use either one instead of p4-clockmod, if possible.\n");
	return speedstep_get_frequency(SPEEDSTEP_CPU_P4M);
	}

	return speedstep_get_frequency(SPEEDSTEP_CPU_P4D);
	}



	static int cpufreq_p4_cpu_init(struct cpufreq_policy *policy)
	{
	struct cpuinfo_x86 *c = &cpu_data(policy->cpu);
	int cpuid = 0;
	unsigned int i;

	#ifdef CONFIG_SMP
	cpumask_copy(policy->cpus, topology_sibling_cpumask(policy->cpu));
	#endif

	/* Errata workaround */
	cpuid = (c->x86 << 8) \| (c->x86_model << 4) \| c->x86_stepping;
	switch (cpuid) {
	case 0x0f07:
	case 0x0f0a:
	case 0x0f11:
	case 0x0f12:
	has_N44_O17_errata[policy->cpu] = 1;
	pr_debug("has errata -- disabling low frequencies\n");
	}

	if (speedstep_detect_processor() == SPEEDSTEP_CPU_P4D &&
	c->x86_model < 2) {
	/* switch to maximum frequency and measure result */
	cpufreq_p4_setdc(policy->cpu, DC_DISABLE);
	recalibrate_cpu_khz();
	}
	/* get max frequency */
	stock_freq = cpufreq_p4_get_frequency(c);
	if (!stock_freq)
	return -EINVAL;

	/* table init */
	for (i = 1; (p4clockmod_table[i].frequency != CPUFREQ_TABLE_END); i++) {
	if ((i < 2) && (has_N44_O17_errata[policy->cpu]))
	p4clockmod_table[i].frequency = CPUFREQ_ENTRY_INVALID;
	else
	p4clockmod_table[i].frequency = (stock_freq * i)/8;
	}

	/* cpuinfo and default policy values */

	/* the transition latency is set to be 1 higher than the maximum
	* transition latency of the ondemand governor */
	policy->cpuinfo.transition_latency = 10000001;
	policy->freq_table = &p4clockmod_table[0];

	return 0;
	}


	static unsigned int cpufreq_p4_get(unsigned int cpu)
	{
	u32 l, h;

	rdmsr_on_cpu(cpu, MSR_IA32_THERM_CONTROL, &l, &h);

	if (l & 0x10) {
	l = l >> 1;
	l &= 0x7;
	} else
	l = DC_DISABLE;

	if (l != DC_DISABLE)
	return stock_freq * l / 8;

	return stock_freq;
	}

	static struct cpufreq_driver p4clockmod_driver = {
	.verify = cpufreq_generic_frequency_table_verify,
	.target_index = cpufreq_p4_target,
	.init = cpufreq_p4_cpu_init,
	.get = cpufreq_p4_get,
	.name = "p4-clockmod",
	.attr = cpufreq_generic_attr,
	};

	static const struct x86_cpu_id cpufreq_p4_id[] = {
	{ X86_VENDOR_INTEL, X86_FAMILY_ANY, X86_MODEL_ANY, X86_FEATURE_ACC },
	{}
	};

	/*
	* Intentionally no MODULE_DEVICE_TABLE here: this driver should not
	* be auto loaded. Please don't add one.
	*/

	static int __init cpufreq_p4_init(void)
	{
	int ret;

	/*
	* THERM_CONTROL is architectural for IA32 now, so
	* we can rely on the capability checks
	*/
	if (!x86_match_cpu(cpufreq_p4_id) \|\| !boot_cpu_has(X86_FEATURE_ACPI))
	return -ENODEV;

	ret = cpufreq_register_driver(&p4clockmod_driver);
	if (!ret)
	pr_info("P4/Xeon(TM) CPU On-Demand Clock Modulation available\n");

	return ret;
	}


	static void __exit cpufreq_p4_exit(void)
	{
	cpufreq_unregister_driver(&p4clockmod_driver);
	}


	MODULE_AUTHOR("Zwane Mwaikambo <zwane@commfireservices.com>");
	MODULE_DESCRIPTION("cpufreq driver for Pentium(TM) 4/Xeon(TM)");
	MODULE_LICENSE("GPL");

	late_initcall(cpufreq_p4_init);
	module_exit(cpufreq_p4_exit);