138 строки
2.8 KiB
C
138 строки
2.8 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
|
|
/*
|
|
* sc520_freq.c: cpufreq driver for the AMD Elan sc520
|
|
*
|
|
* Copyright (C) 2005 Sean Young <sean@mess.org>
|
|
*
|
|
* Based on elanfreq.c
|
|
*
|
|
* 2005-03-30: - initial revision
|
|
*/
|
|
|
|
#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 <linux/timex.h>
|
|
#include <linux/io.h>
|
|
|
|
#include <asm/cpu_device_id.h>
|
|
#include <asm/msr.h>
|
|
|
|
#define MMCR_BASE 0xfffef000 /* The default base address */
|
|
#define OFFS_CPUCTL 0x2 /* CPU Control Register */
|
|
|
|
static __u8 __iomem *cpuctl;
|
|
|
|
static struct cpufreq_frequency_table sc520_freq_table[] = {
|
|
{0, 0x01, 100000},
|
|
{0, 0x02, 133000},
|
|
{0, 0, CPUFREQ_TABLE_END},
|
|
};
|
|
|
|
static unsigned int sc520_freq_get_cpu_frequency(unsigned int cpu)
|
|
{
|
|
u8 clockspeed_reg = *cpuctl;
|
|
|
|
switch (clockspeed_reg & 0x03) {
|
|
default:
|
|
pr_err("error: cpuctl register has unexpected value %02x\n",
|
|
clockspeed_reg);
|
|
case 0x01:
|
|
return 100000;
|
|
case 0x02:
|
|
return 133000;
|
|
}
|
|
}
|
|
|
|
static int sc520_freq_target(struct cpufreq_policy *policy, unsigned int state)
|
|
{
|
|
|
|
u8 clockspeed_reg;
|
|
|
|
local_irq_disable();
|
|
|
|
clockspeed_reg = *cpuctl & ~0x03;
|
|
*cpuctl = clockspeed_reg | sc520_freq_table[state].driver_data;
|
|
|
|
local_irq_enable();
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Module init and exit code
|
|
*/
|
|
|
|
static int sc520_freq_cpu_init(struct cpufreq_policy *policy)
|
|
{
|
|
struct cpuinfo_x86 *c = &cpu_data(0);
|
|
|
|
/* capability check */
|
|
if (c->x86_vendor != X86_VENDOR_AMD ||
|
|
c->x86 != 4 || c->x86_model != 9)
|
|
return -ENODEV;
|
|
|
|
/* cpuinfo and default policy values */
|
|
policy->cpuinfo.transition_latency = 1000000; /* 1ms */
|
|
policy->freq_table = sc520_freq_table;
|
|
|
|
return 0;
|
|
}
|
|
|
|
|
|
static struct cpufreq_driver sc520_freq_driver = {
|
|
.get = sc520_freq_get_cpu_frequency,
|
|
.verify = cpufreq_generic_frequency_table_verify,
|
|
.target_index = sc520_freq_target,
|
|
.init = sc520_freq_cpu_init,
|
|
.name = "sc520_freq",
|
|
.attr = cpufreq_generic_attr,
|
|
};
|
|
|
|
static const struct x86_cpu_id sc520_ids[] = {
|
|
X86_MATCH_VENDOR_FAM_MODEL(AMD, 4, 9, NULL),
|
|
{}
|
|
};
|
|
MODULE_DEVICE_TABLE(x86cpu, sc520_ids);
|
|
|
|
static int __init sc520_freq_init(void)
|
|
{
|
|
int err;
|
|
|
|
if (!x86_match_cpu(sc520_ids))
|
|
return -ENODEV;
|
|
|
|
cpuctl = ioremap((unsigned long)(MMCR_BASE + OFFS_CPUCTL), 1);
|
|
if (!cpuctl) {
|
|
pr_err("sc520_freq: error: failed to remap memory\n");
|
|
return -ENOMEM;
|
|
}
|
|
|
|
err = cpufreq_register_driver(&sc520_freq_driver);
|
|
if (err)
|
|
iounmap(cpuctl);
|
|
|
|
return err;
|
|
}
|
|
|
|
|
|
static void __exit sc520_freq_exit(void)
|
|
{
|
|
cpufreq_unregister_driver(&sc520_freq_driver);
|
|
iounmap(cpuctl);
|
|
}
|
|
|
|
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_AUTHOR("Sean Young <sean@mess.org>");
|
|
MODULE_DESCRIPTION("cpufreq driver for AMD's Elan sc520 CPU");
|
|
|
|
module_init(sc520_freq_init);
|
|
module_exit(sc520_freq_exit);
|
|
|