| /* |
| * sc520_freq.c: cpufreq driver for the AMD Elan sc520 |
| * |
| * Copyright (C) 2005 Sean Young <sean@mess.org> |
| * |
| * 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. |
| * |
| * Based on elanfreq.c |
| * |
| * 2005-03-30: - initial revision |
| */ |
| |
| #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; |
| |
| #define PFX "sc520_freq: " |
| |
| static struct cpufreq_frequency_table sc520_freq_table[] = { |
| {0x01, 100000}, |
| {0x02, 133000}, |
| {0, CPUFREQ_TABLE_END}, |
| }; |
| |
| static unsigned int sc520_freq_get_cpu_frequency(unsigned int cpu) |
| { |
| u8 clockspeed_reg = *cpuctl; |
| |
| switch (clockspeed_reg & 0x03) { |
| default: |
| printk(KERN_ERR PFX "error: cpuctl register has unexpected " |
| "value %02x\n", clockspeed_reg); |
| case 0x01: |
| return 100000; |
| case 0x02: |
| return 133000; |
| } |
| } |
| |
| static void sc520_freq_set_cpu_state(struct cpufreq_policy *policy, |
| unsigned int state) |
| { |
| |
| struct cpufreq_freqs freqs; |
| u8 clockspeed_reg; |
| |
| freqs.old = sc520_freq_get_cpu_frequency(0); |
| freqs.new = sc520_freq_table[state].frequency; |
| |
| cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE); |
| |
| pr_debug("attempting to set frequency to %i kHz\n", |
| sc520_freq_table[state].frequency); |
| |
| local_irq_disable(); |
| |
| clockspeed_reg = *cpuctl & ~0x03; |
| *cpuctl = clockspeed_reg | sc520_freq_table[state].driver_data; |
| |
| local_irq_enable(); |
| |
| cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE); |
| }; |
| |
| static int sc520_freq_target(struct cpufreq_policy *policy, |
| unsigned int target_freq, |
| unsigned int relation) |
| { |
| unsigned int newstate = 0; |
| |
| if (cpufreq_frequency_table_target(policy, sc520_freq_table, |
| target_freq, relation, &newstate)) |
| return -EINVAL; |
| |
| sc520_freq_set_cpu_state(policy, newstate); |
| |
| 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 */ |
| |
| return cpufreq_table_validate_and_show(policy, sc520_freq_table); |
| } |
| |
| |
| static struct cpufreq_driver sc520_freq_driver = { |
| .get = sc520_freq_get_cpu_frequency, |
| .verify = cpufreq_generic_frequency_table_verify, |
| .target = sc520_freq_target, |
| .init = sc520_freq_cpu_init, |
| .exit = cpufreq_generic_exit, |
| .name = "sc520_freq", |
| .attr = cpufreq_generic_attr, |
| }; |
| |
| static const struct x86_cpu_id sc520_ids[] = { |
| { X86_VENDOR_AMD, 4, 9 }, |
| {} |
| }; |
| 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) { |
| printk(KERN_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); |
| |