| /* |
| * 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 <asm/msr.h> |
| #include <asm/timex.h> |
| #include <asm/io.h> |
| |
| #define MMCR_BASE 0xfffef000 /* The default base address */ |
| #define OFFS_CPUCTL 0x2 /* CPU Control Register */ |
| |
| static __u8 __iomem *cpuctl; |
| |
| #define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_DRIVER, "sc520_freq", msg) |
| |
| 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 "sc520_freq: 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 (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; |
| freqs.cpu = 0; /* AMD Elan is UP */ |
| |
| cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE); |
| |
| dprintk("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].index; |
| |
| local_irq_enable(); |
| |
| cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE); |
| }; |
| |
| static int sc520_freq_verify (struct cpufreq_policy *policy) |
| { |
| return cpufreq_frequency_table_verify(policy, &sc520_freq_table[0]); |
| } |
| |
| 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(newstate); |
| |
| return 0; |
| } |
| |
| |
| /* |
| * Module init and exit code |
| */ |
| |
| static int sc520_freq_cpu_init(struct cpufreq_policy *policy) |
| { |
| struct cpuinfo_x86 *c = cpu_data; |
| int result; |
| |
| /* capability check */ |
| if (c->x86_vendor != X86_VENDOR_AMD || |
| c->x86 != 4 || c->x86_model != 9) |
| return -ENODEV; |
| |
| /* cpuinfo and default policy values */ |
| policy->governor = CPUFREQ_DEFAULT_GOVERNOR; |
| policy->cpuinfo.transition_latency = 1000000; /* 1ms */ |
| policy->cur = sc520_freq_get_cpu_frequency(0); |
| |
| result = cpufreq_frequency_table_cpuinfo(policy, sc520_freq_table); |
| if (result) |
| return (result); |
| |
| cpufreq_frequency_table_get_attr(sc520_freq_table, policy->cpu); |
| |
| return 0; |
| } |
| |
| |
| static int sc520_freq_cpu_exit(struct cpufreq_policy *policy) |
| { |
| cpufreq_frequency_table_put_attr(policy->cpu); |
| return 0; |
| } |
| |
| |
| static struct freq_attr* sc520_freq_attr[] = { |
| &cpufreq_freq_attr_scaling_available_freqs, |
| NULL, |
| }; |
| |
| |
| static struct cpufreq_driver sc520_freq_driver = { |
| .get = sc520_freq_get_cpu_frequency, |
| .verify = sc520_freq_verify, |
| .target = sc520_freq_target, |
| .init = sc520_freq_cpu_init, |
| .exit = sc520_freq_cpu_exit, |
| .name = "sc520_freq", |
| .owner = THIS_MODULE, |
| .attr = sc520_freq_attr, |
| }; |
| |
| |
| static int __init sc520_freq_init(void) |
| { |
| struct cpuinfo_x86 *c = cpu_data; |
| |
| /* Test if we have the right hardware */ |
| if(c->x86_vendor != X86_VENDOR_AMD || |
| c->x86 != 4 || c->x86_model != 9) { |
| dprintk("no Elan SC520 processor found!\n"); |
| 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; |
| } |
| |
| return cpufreq_register_driver(&sc520_freq_driver); |
| } |
| |
| |
| 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); |
| |