linux/drivers/cpufreq/p4-clockmod.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *	Pentium 4/Xeon CPU on demand clock modulation/speed scaling
 *	(C) 2002 - 2003 Dominik Brodowski <[email protected]>
 *	(C) 2002 Zwane Mwaikambo <[email protected]>
 *	(C) 2002 Arjan van de Ven <[email protected]>
 *	(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) …

#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 { … };

#define DC_ENTRIES …


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)
{ … }


static struct cpufreq_frequency_table p4clockmod_table[] = …;


static int cpufreq_p4_target(struct cpufreq_policy *policy, unsigned int index)
{ … }


static unsigned int cpufreq_p4_get_frequency(struct cpuinfo_x86 *c)
{ … }



static int cpufreq_p4_cpu_init(struct cpufreq_policy *policy)
{ … }


static unsigned int cpufreq_p4_get(unsigned int cpu)
{ … }

static struct cpufreq_driver p4clockmod_driver = …;

static const struct x86_cpu_id cpufreq_p4_id[] = …;

/*
 * 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)
{ … }


static void __exit cpufreq_p4_exit(void)
{ … }


MODULE_AUTHOR(…) …;
MODULE_DESCRIPTION(…) …;
MODULE_LICENSE(…) …;

late_initcall(cpufreq_p4_init);
module_exit(cpufreq_p4_exit);