diff options
Diffstat (limited to 'drivers/cpufreq/loongson2_cpufreq.c')
| -rw-r--r-- | drivers/cpufreq/loongson2_cpufreq.c | 184 |
1 files changed, 184 insertions, 0 deletions
diff --git a/drivers/cpufreq/loongson2_cpufreq.c b/drivers/cpufreq/loongson2_cpufreq.c new file mode 100644 index 0000000000..afc59b2921 --- /dev/null +++ b/drivers/cpufreq/loongson2_cpufreq.c @@ -0,0 +1,184 @@ +/* + * 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/delay.h> +#include <linux/platform_device.h> + +#include <asm/idle.h> + +#include <asm/mach-loongson2ef/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 */ + loongson2_cpu_set_rate(freq); + + return 0; +} + +static int loongson2_cpufreq_cpu_init(struct cpufreq_policy *policy) +{ + int i; + unsigned long rate; + int ret; + + rate = cpu_clock_freq / 1000; + if (!rate) + 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 = loongson2_cpu_set_rate(rate); + if (ret) + return ret; + + cpufreq_generic_init(policy, &loongson2_clockmod_table[0], 0); + return 0; +} + +static int loongson2_cpufreq_exit(struct cpufreq_policy *policy) +{ + 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 const 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 = readl(LOONGSON_CHIPCFG); + /* Put CPU into wait mode */ + writel(readl(LOONGSON_CHIPCFG) & ~0x7, LOONGSON_CHIPCFG); + /* Restore CPU state */ + writel(cpu_freq, LOONGSON_CHIPCFG); + 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"); |