linux/drivers/cpufreq/p4-clockmod.c
Thomas Gleixner 2874c5fd28 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152
Based on 1 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation either version 2 of the license or at
  your option any later version

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 3029 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-30 11:26:32 -07:00

274 lines
6.9 KiB
C

// 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);