linux/drivers/cpufreq/elanfreq.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

229 lines
5.5 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* elanfreq: cpufreq driver for the AMD ELAN family
*
* (c) Copyright 2002 Robert Schwebel <r.schwebel@pengutronix.de>
*
* Parts of this code are (c) Sven Geggus <sven@geggus.net>
*
* All Rights Reserved.
*
* 2002-02-13: - initial revision for 2.4.18-pre9 by Robert Schwebel
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/cpufreq.h>
#include <asm/cpu_device_id.h>
#include <asm/msr.h>
#include <linux/timex.h>
#include <linux/io.h>
#define REG_CSCIR 0x22 /* Chip Setup and Control Index Register */
#define REG_CSCDR 0x23 /* Chip Setup and Control Data Register */
/* Module parameter */
static int max_freq;
struct s_elan_multiplier {
int clock; /* frequency in kHz */
int val40h; /* PMU Force Mode register */
int val80h; /* CPU Clock Speed Register */
};
/*
* It is important that the frequencies
* are listed in ascending order here!
*/
static struct s_elan_multiplier elan_multiplier[] = {
{1000, 0x02, 0x18},
{2000, 0x02, 0x10},
{4000, 0x02, 0x08},
{8000, 0x00, 0x00},
{16000, 0x00, 0x02},
{33000, 0x00, 0x04},
{66000, 0x01, 0x04},
{99000, 0x01, 0x05}
};
static struct cpufreq_frequency_table elanfreq_table[] = {
{0, 0, 1000},
{0, 1, 2000},
{0, 2, 4000},
{0, 3, 8000},
{0, 4, 16000},
{0, 5, 33000},
{0, 6, 66000},
{0, 7, 99000},
{0, 0, CPUFREQ_TABLE_END},
};
/**
* elanfreq_get_cpu_frequency: determine current cpu speed
*
* Finds out at which frequency the CPU of the Elan SOC runs
* at the moment. Frequencies from 1 to 33 MHz are generated
* the normal way, 66 and 99 MHz are called "Hyperspeed Mode"
* and have the rest of the chip running with 33 MHz.
*/
static unsigned int elanfreq_get_cpu_frequency(unsigned int cpu)
{
u8 clockspeed_reg; /* Clock Speed Register */
local_irq_disable();
outb_p(0x80, REG_CSCIR);
clockspeed_reg = inb_p(REG_CSCDR);
local_irq_enable();
if ((clockspeed_reg & 0xE0) == 0xE0)
return 0;
/* Are we in CPU clock multiplied mode (66/99 MHz)? */
if ((clockspeed_reg & 0xE0) == 0xC0) {
if ((clockspeed_reg & 0x01) == 0)
return 66000;
else
return 99000;
}
/* 33 MHz is not 32 MHz... */
if ((clockspeed_reg & 0xE0) == 0xA0)
return 33000;
return (1<<((clockspeed_reg & 0xE0) >> 5)) * 1000;
}
static int elanfreq_target(struct cpufreq_policy *policy,
unsigned int state)
{
/*
* Access to the Elan's internal registers is indexed via
* 0x22: Chip Setup & Control Register Index Register (CSCI)
* 0x23: Chip Setup & Control Register Data Register (CSCD)
*
*/
/*
* 0x40 is the Power Management Unit's Force Mode Register.
* Bit 6 enables Hyperspeed Mode (66/100 MHz core frequency)
*/
local_irq_disable();
outb_p(0x40, REG_CSCIR); /* Disable hyperspeed mode */
outb_p(0x00, REG_CSCDR);
local_irq_enable(); /* wait till internal pipelines and */
udelay(1000); /* buffers have cleaned up */
local_irq_disable();
/* now, set the CPU clock speed register (0x80) */
outb_p(0x80, REG_CSCIR);
outb_p(elan_multiplier[state].val80h, REG_CSCDR);
/* now, the hyperspeed bit in PMU Force Mode Register (0x40) */
outb_p(0x40, REG_CSCIR);
outb_p(elan_multiplier[state].val40h, REG_CSCDR);
udelay(10000);
local_irq_enable();
return 0;
}
/*
* Module init and exit code
*/
static int elanfreq_cpu_init(struct cpufreq_policy *policy)
{
struct cpuinfo_x86 *c = &cpu_data(0);
struct cpufreq_frequency_table *pos;
/* capability check */
if ((c->x86_vendor != X86_VENDOR_AMD) ||
(c->x86 != 4) || (c->x86_model != 10))
return -ENODEV;
/* max freq */
if (!max_freq)
max_freq = elanfreq_get_cpu_frequency(0);
/* table init */
cpufreq_for_each_entry(pos, elanfreq_table)
if (pos->frequency > max_freq)
pos->frequency = CPUFREQ_ENTRY_INVALID;
policy->freq_table = elanfreq_table;
return 0;
}
#ifndef MODULE
/**
* elanfreq_setup - elanfreq command line parameter parsing
*
* elanfreq command line parameter. Use:
* elanfreq=66000
* to set the maximum CPU frequency to 66 MHz. Note that in
* case you do not give this boot parameter, the maximum
* frequency will fall back to _current_ CPU frequency which
* might be lower. If you build this as a module, use the
* max_freq module parameter instead.
*/
static int __init elanfreq_setup(char *str)
{
max_freq = simple_strtoul(str, &str, 0);
pr_warn("You're using the deprecated elanfreq command line option. Use elanfreq.max_freq instead, please!\n");
return 1;
}
__setup("elanfreq=", elanfreq_setup);
#endif
static struct cpufreq_driver elanfreq_driver = {
.get = elanfreq_get_cpu_frequency,
.flags = CPUFREQ_NO_AUTO_DYNAMIC_SWITCHING,
.verify = cpufreq_generic_frequency_table_verify,
.target_index = elanfreq_target,
.init = elanfreq_cpu_init,
.name = "elanfreq",
.attr = cpufreq_generic_attr,
};
static const struct x86_cpu_id elan_id[] = {
{ X86_VENDOR_AMD, 4, 10, },
{}
};
MODULE_DEVICE_TABLE(x86cpu, elan_id);
static int __init elanfreq_init(void)
{
if (!x86_match_cpu(elan_id))
return -ENODEV;
return cpufreq_register_driver(&elanfreq_driver);
}
static void __exit elanfreq_exit(void)
{
cpufreq_unregister_driver(&elanfreq_driver);
}
module_param(max_freq, int, 0444);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Robert Schwebel <r.schwebel@pengutronix.de>, "
"Sven Geggus <sven@geggus.net>");
MODULE_DESCRIPTION("cpufreq driver for AMD's Elan CPUs");
module_init(elanfreq_init);
module_exit(elanfreq_exit);