186 lines
4.3 KiB
C
186 lines
4.3 KiB
C
/*
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* Cpufreq driver for the loongson-2 processors
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*
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* The 2E revision of loongson processor not support this feature.
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*
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* Copyright (C) 2006 - 2008 Lemote Inc. & Institute of Computing Technology
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* Author: Yanhua, yanh@lemote.com
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*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file "COPYING" in the main directory of this archive
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* for more details.
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/cpufreq.h>
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#include <linux/module.h>
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#include <linux/err.h>
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#include <linux/sched.h> /* set_cpus_allowed() */
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#include <linux/delay.h>
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#include <linux/platform_device.h>
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#include <asm/idle.h>
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#include <asm/mach-loongson2ef/loongson.h>
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static uint nowait;
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static void (*saved_cpu_wait) (void);
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static int loongson2_cpu_freq_notifier(struct notifier_block *nb,
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unsigned long val, void *data);
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static struct notifier_block loongson2_cpufreq_notifier_block = {
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.notifier_call = loongson2_cpu_freq_notifier
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};
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static int loongson2_cpu_freq_notifier(struct notifier_block *nb,
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unsigned long val, void *data)
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{
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if (val == CPUFREQ_POSTCHANGE)
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current_cpu_data.udelay_val = loops_per_jiffy;
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return 0;
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}
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/*
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* Here we notify other drivers of the proposed change and the final change.
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*/
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static int loongson2_cpufreq_target(struct cpufreq_policy *policy,
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unsigned int index)
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{
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unsigned int freq;
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freq =
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((cpu_clock_freq / 1000) *
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loongson2_clockmod_table[index].driver_data) / 8;
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/* setting the cpu frequency */
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loongson2_cpu_set_rate(freq);
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return 0;
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}
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static int loongson2_cpufreq_cpu_init(struct cpufreq_policy *policy)
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{
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int i;
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unsigned long rate;
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int ret;
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rate = cpu_clock_freq / 1000;
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if (!rate)
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return -EINVAL;
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/* clock table init */
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for (i = 2;
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(loongson2_clockmod_table[i].frequency != CPUFREQ_TABLE_END);
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i++)
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loongson2_clockmod_table[i].frequency = (rate * i) / 8;
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ret = loongson2_cpu_set_rate(rate);
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if (ret)
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return ret;
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cpufreq_generic_init(policy, &loongson2_clockmod_table[0], 0);
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return 0;
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}
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static int loongson2_cpufreq_exit(struct cpufreq_policy *policy)
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{
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return 0;
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}
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static struct cpufreq_driver loongson2_cpufreq_driver = {
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.name = "loongson2",
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.init = loongson2_cpufreq_cpu_init,
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.verify = cpufreq_generic_frequency_table_verify,
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.target_index = loongson2_cpufreq_target,
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.get = cpufreq_generic_get,
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.exit = loongson2_cpufreq_exit,
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.attr = cpufreq_generic_attr,
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};
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static const struct platform_device_id platform_device_ids[] = {
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{
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.name = "loongson2_cpufreq",
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},
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{}
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};
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MODULE_DEVICE_TABLE(platform, platform_device_ids);
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static struct platform_driver platform_driver = {
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.driver = {
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.name = "loongson2_cpufreq",
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},
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.id_table = platform_device_ids,
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};
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/*
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* This is the simple version of Loongson-2 wait, Maybe we need do this in
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* interrupt disabled context.
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*/
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static DEFINE_SPINLOCK(loongson2_wait_lock);
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static void loongson2_cpu_wait(void)
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{
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unsigned long flags;
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u32 cpu_freq;
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spin_lock_irqsave(&loongson2_wait_lock, flags);
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cpu_freq = readl(LOONGSON_CHIPCFG);
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/* Put CPU into wait mode */
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writel(readl(LOONGSON_CHIPCFG) & ~0x7, LOONGSON_CHIPCFG);
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/* Restore CPU state */
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writel(cpu_freq, LOONGSON_CHIPCFG);
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spin_unlock_irqrestore(&loongson2_wait_lock, flags);
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local_irq_enable();
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}
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static int __init cpufreq_init(void)
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{
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int ret;
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/* Register platform stuff */
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ret = platform_driver_register(&platform_driver);
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if (ret)
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return ret;
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pr_info("Loongson-2F CPU frequency driver\n");
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cpufreq_register_notifier(&loongson2_cpufreq_notifier_block,
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CPUFREQ_TRANSITION_NOTIFIER);
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ret = cpufreq_register_driver(&loongson2_cpufreq_driver);
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if (!ret && !nowait) {
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saved_cpu_wait = cpu_wait;
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cpu_wait = loongson2_cpu_wait;
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}
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return ret;
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}
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static void __exit cpufreq_exit(void)
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{
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if (!nowait && saved_cpu_wait)
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cpu_wait = saved_cpu_wait;
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cpufreq_unregister_driver(&loongson2_cpufreq_driver);
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cpufreq_unregister_notifier(&loongson2_cpufreq_notifier_block,
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CPUFREQ_TRANSITION_NOTIFIER);
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platform_driver_unregister(&platform_driver);
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}
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module_init(cpufreq_init);
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module_exit(cpufreq_exit);
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module_param(nowait, uint, 0644);
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MODULE_PARM_DESC(nowait, "Disable Loongson-2F specific wait");
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MODULE_AUTHOR("Yanhua <yanh@lemote.com>");
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MODULE_DESCRIPTION("cpufreq driver for Loongson2F");
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MODULE_LICENSE("GPL");
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