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1/*2 * Cpufreq driver for the loongson-2 processors3 *4 * The 2E revision of loongson processor not support this feature.5 *6 * Copyright (C) 2006 - 2008 Lemote Inc. & Institute of Computing Technology7 * Author: Yanhua, yanh@lemote.com8 *9 * This file is subject to the terms and conditions of the GNU General Public10 * License. See the file "COPYING" in the main directory of this archive11 * for more details.12 */13 14#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt15 16#include <linux/cpufreq.h>17#include <linux/module.h>18#include <linux/err.h>19#include <linux/delay.h>20#include <linux/platform_device.h>21 22#include <asm/idle.h>23 24#include <asm/mach-loongson2ef/loongson.h>25 26static uint nowait;27 28static void (*saved_cpu_wait) (void);29 30static int loongson2_cpu_freq_notifier(struct notifier_block *nb,31 unsigned long val, void *data);32 33static struct notifier_block loongson2_cpufreq_notifier_block = {34 .notifier_call = loongson2_cpu_freq_notifier35};36 37static int loongson2_cpu_freq_notifier(struct notifier_block *nb,38 unsigned long val, void *data)39{40 if (val == CPUFREQ_POSTCHANGE)41 current_cpu_data.udelay_val = loops_per_jiffy;42 43 return 0;44}45 46/*47 * Here we notify other drivers of the proposed change and the final change.48 */49static int loongson2_cpufreq_target(struct cpufreq_policy *policy,50 unsigned int index)51{52 unsigned int freq;53 54 freq =55 ((cpu_clock_freq / 1000) *56 loongson2_clockmod_table[index].driver_data) / 8;57 58 /* setting the cpu frequency */59 loongson2_cpu_set_rate(freq);60 61 return 0;62}63 64static int loongson2_cpufreq_cpu_init(struct cpufreq_policy *policy)65{66 int i;67 unsigned long rate;68 int ret;69 70 rate = cpu_clock_freq / 1000;71 if (!rate)72 return -EINVAL;73 74 /* clock table init */75 for (i = 2;76 (loongson2_clockmod_table[i].frequency != CPUFREQ_TABLE_END);77 i++)78 loongson2_clockmod_table[i].frequency = (rate * i) / 8;79 80 ret = loongson2_cpu_set_rate(rate);81 if (ret)82 return ret;83 84 cpufreq_generic_init(policy, &loongson2_clockmod_table[0], 0);85 return 0;86}87 88static struct cpufreq_driver loongson2_cpufreq_driver = {89 .name = "loongson2",90 .init = loongson2_cpufreq_cpu_init,91 .verify = cpufreq_generic_frequency_table_verify,92 .target_index = loongson2_cpufreq_target,93 .get = cpufreq_generic_get,94 .attr = cpufreq_generic_attr,95};96 97static const struct platform_device_id platform_device_ids[] = {98 {99 .name = "loongson2_cpufreq",100 },101 {}102};103 104MODULE_DEVICE_TABLE(platform, platform_device_ids);105 106static struct platform_driver platform_driver = {107 .driver = {108 .name = "loongson2_cpufreq",109 },110 .id_table = platform_device_ids,111};112 113/*114 * This is the simple version of Loongson-2 wait, Maybe we need do this in115 * interrupt disabled context.116 */117 118static DEFINE_SPINLOCK(loongson2_wait_lock);119 120static void loongson2_cpu_wait(void)121{122 unsigned long flags;123 u32 cpu_freq;124 125 spin_lock_irqsave(&loongson2_wait_lock, flags);126 cpu_freq = readl(LOONGSON_CHIPCFG);127 /* Put CPU into wait mode */128 writel(readl(LOONGSON_CHIPCFG) & ~0x7, LOONGSON_CHIPCFG);129 /* Restore CPU state */130 writel(cpu_freq, LOONGSON_CHIPCFG);131 spin_unlock_irqrestore(&loongson2_wait_lock, flags);132 local_irq_enable();133}134 135static int __init cpufreq_init(void)136{137 int ret;138 139 /* Register platform stuff */140 ret = platform_driver_register(&platform_driver);141 if (ret)142 return ret;143 144 pr_info("Loongson-2F CPU frequency driver\n");145 146 cpufreq_register_notifier(&loongson2_cpufreq_notifier_block,147 CPUFREQ_TRANSITION_NOTIFIER);148 149 ret = cpufreq_register_driver(&loongson2_cpufreq_driver);150 151 if (!ret && !nowait) {152 saved_cpu_wait = cpu_wait;153 cpu_wait = loongson2_cpu_wait;154 }155 156 return ret;157}158 159static void __exit cpufreq_exit(void)160{161 if (!nowait && saved_cpu_wait)162 cpu_wait = saved_cpu_wait;163 cpufreq_unregister_driver(&loongson2_cpufreq_driver);164 cpufreq_unregister_notifier(&loongson2_cpufreq_notifier_block,165 CPUFREQ_TRANSITION_NOTIFIER);166 167 platform_driver_unregister(&platform_driver);168}169 170module_init(cpufreq_init);171module_exit(cpufreq_exit);172 173module_param(nowait, uint, 0644);174MODULE_PARM_DESC(nowait, "Disable Loongson-2F specific wait");175 176MODULE_AUTHOR("Yanhua <yanh@lemote.com>");177MODULE_DESCRIPTION("cpufreq driver for Loongson2F");178MODULE_LICENSE("GPL");179