/* * Cpufreq driver for the loongson-2 processors * * The 2E revision of loongson processor not support this feature. * * Copyright (C) 2006 - 2008 Lemote Inc. & Institute of Computing Technology * Author: Yanhua, yanh@lemote.com * * This file is subject to the terms and conditions of the GNU General Public * License. See the file "COPYING" in the main directory of this archive * for more details. */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include <linux/cpufreq.h> #include <linux/module.h> #include <linux/err.h> #include <linux/sched.h> /* set_cpus_allowed() */ #include <linux/delay.h> #include <linux/platform_device.h> #include <asm/clock.h> #include <asm/idle.h> #include <asm/mach-loongson64/loongson.h> static uint nowait; static void (*saved_cpu_wait) (void); static int loongson2_cpu_freq_notifier(struct notifier_block *nb, unsigned long val, void *data); static struct notifier_block loongson2_cpufreq_notifier_block = { .notifier_call = loongson2_cpu_freq_notifier }; static int loongson2_cpu_freq_notifier(struct notifier_block *nb, unsigned long val, void *data) { if (val == CPUFREQ_POSTCHANGE) current_cpu_data.udelay_val = loops_per_jiffy; return 0; } /* * Here we notify other drivers of the proposed change and the final change. */ static int loongson2_cpufreq_target(struct cpufreq_policy *policy, unsigned int index) { unsigned int freq; freq = ((cpu_clock_freq / 1000) * loongson2_clockmod_table[index].driver_data) / 8; /* setting the cpu frequency */ clk_set_rate(policy->clk, freq * 1000); return 0; } static int loongson2_cpufreq_cpu_init(struct cpufreq_policy *policy) { struct clk *cpuclk; int i; unsigned long rate; int ret; cpuclk = clk_get(NULL, "cpu_clk"); if (IS_ERR(cpuclk)) { pr_err("couldn't get CPU clk\n"); return PTR_ERR(cpuclk); } rate = cpu_clock_freq / 1000; if (!rate) { clk_put(cpuclk); return -EINVAL; } /* clock table init */ for (i = 2; (loongson2_clockmod_table[i].frequency != CPUFREQ_TABLE_END); i++) loongson2_clockmod_table[i].frequency = (rate * i) / 8; ret = clk_set_rate(cpuclk, rate * 1000); if (ret) { clk_put(cpuclk); return ret; } policy->clk = cpuclk; return cpufreq_generic_init(policy, &loongson2_clockmod_table[0], 0); } static int loongson2_cpufreq_exit(struct cpufreq_policy *policy) { clk_put(policy->clk); return 0; } static struct cpufreq_driver loongson2_cpufreq_driver = { .name = "loongson2", .init = loongson2_cpufreq_cpu_init, .verify = cpufreq_generic_frequency_table_verify, .target_index = loongson2_cpufreq_target, .get = cpufreq_generic_get, .exit = loongson2_cpufreq_exit, .attr = cpufreq_generic_attr, }; static struct platform_device_id platform_device_ids[] = { { .name = "loongson2_cpufreq", }, {} }; MODULE_DEVICE_TABLE(platform, platform_device_ids); static struct platform_driver platform_driver = { .driver = { .name = "loongson2_cpufreq", }, .id_table = platform_device_ids, }; /* * This is the simple version of Loongson-2 wait, Maybe we need do this in * interrupt disabled context. */ static DEFINE_SPINLOCK(loongson2_wait_lock); static void loongson2_cpu_wait(void) { unsigned long flags; u32 cpu_freq; spin_lock_irqsave(&loongson2_wait_lock, flags); cpu_freq = LOONGSON_CHIPCFG(0); LOONGSON_CHIPCFG(0) &= ~0x7; /* Put CPU into wait mode */ LOONGSON_CHIPCFG(0) = cpu_freq; /* Restore CPU state */ spin_unlock_irqrestore(&loongson2_wait_lock, flags); local_irq_enable(); } static int __init cpufreq_init(void) { int ret; /* Register platform stuff */ ret = platform_driver_register(&platform_driver); if (ret) return ret; pr_info("Loongson-2F CPU frequency driver\n"); cpufreq_register_notifier(&loongson2_cpufreq_notifier_block, CPUFREQ_TRANSITION_NOTIFIER); ret = cpufreq_register_driver(&loongson2_cpufreq_driver); if (!ret && !nowait) { saved_cpu_wait = cpu_wait; cpu_wait = loongson2_cpu_wait; } return ret; } static void __exit cpufreq_exit(void) { if (!nowait && saved_cpu_wait) cpu_wait = saved_cpu_wait; cpufreq_unregister_driver(&loongson2_cpufreq_driver); cpufreq_unregister_notifier(&loongson2_cpufreq_notifier_block, CPUFREQ_TRANSITION_NOTIFIER); platform_driver_unregister(&platform_driver); } module_init(cpufreq_init); module_exit(cpufreq_exit); module_param(nowait, uint, 0644); MODULE_PARM_DESC(nowait, "Disable Loongson-2F specific wait"); MODULE_AUTHOR("Yanhua <yanh@lemote.com>"); MODULE_DESCRIPTION("cpufreq driver for Loongson2F"); MODULE_LICENSE("GPL");