[mirror_ubuntu-hirsute-kernel.git] / drivers / cpufreq / loongson2_cpufreq.c

/*
 * 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/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");
Commit	Line	Data
f8ede0f7 WZ	1	/*
	2	* Cpufreq driver for the loongson-2 processors
	3	*
	4	* The 2E revision of loongson processor not support this feature.
	5	*
0bb383a2	6	* Copyright (C) 2006 - 2008 Lemote Inc. & Institute of Computing Technology
f8ede0f7 WZ	7	* Author: Yanhua, yanh@lemote.com
	8	*
	9	* This file is subject to the terms and conditions of the GNU General Public
	10	* License. See the file "COPYING" in the main directory of this archive
	11	* for more details.
	12	*/
1c5864e2 JP	13
	14	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
	15
f8ede0f7 WZ	16	#include <linux/cpufreq.h>
	17	#include <linux/module.h>
	18	#include <linux/err.h>
	19	#include <linux/sched.h> /* set_cpus_allowed() */
	20	#include <linux/delay.h>
	21	#include <linux/platform_device.h>
	22
bdc92d74	23	#include <asm/idle.h>
f8ede0f7	24
71e2f4dd	25	#include <asm/mach-loongson2ef/loongson.h>
f8ede0f7 WZ	26
	27	static uint nowait;
	28
f8ede0f7 WZ	29	static void (*saved_cpu_wait) (void);
	30
	31	static int loongson2_cpu_freq_notifier(struct notifier_block *nb,
	32	unsigned long val, void *data);
	33
	34	static struct notifier_block loongson2_cpufreq_notifier_block = {
	35	.notifier_call = loongson2_cpu_freq_notifier
	36	};
	37
	38	static int loongson2_cpu_freq_notifier(struct notifier_block *nb,
	39	unsigned long val, void *data)
	40	{
	41	if (val == CPUFREQ_POSTCHANGE)
	42	current_cpu_data.udelay_val = loops_per_jiffy;
	43
	44	return 0;
	45	}
	46
f8ede0f7 WZ	47	/*
	48	* Here we notify other drivers of the proposed change and the final change.
	49	*/
	50	static int loongson2_cpufreq_target(struct cpufreq_policy *policy,
9c0ebcf7	51	unsigned int index)
f8ede0f7	52	{
f8ede0f7 WZ	53	unsigned int freq;
f8ede0f7 WZ	54
f8ede0f7 WZ	55	freq =
f8ede0f7 WZ	56	((cpu_clock_freq / 1000) *
9c0ebcf7	57	loongson2_clockmod_table[index].driver_data) / 8;
f8ede0f7	58
f8ede0f7	59	/* setting the cpu frequency */
c02e9630	60	loongson2_cpu_set_rate(freq);
f8ede0f7	61
f8ede0f7 WZ	62	return 0;
	63	}
	64
	65	static int loongson2_cpufreq_cpu_init(struct cpufreq_policy *policy)
	66	{
	67	int i;
42913c79 JL	68	unsigned long rate;
42913c79 JL	69	int ret;
f8ede0f7	70
42913c79	71	rate = cpu_clock_freq / 1000;
c02e9630	72	if (!rate)
f8ede0f7 WZ	73	return -EINVAL;
	74
	75	/* clock table init */
	76	for (i = 2;
	77	(loongson2_clockmod_table[i].frequency != CPUFREQ_TABLE_END);
	78	i++)
42913c79	79	loongson2_clockmod_table[i].frequency = (rate * i) / 8;
f8ede0f7	80
c02e9630 AB	81	ret = loongson2_cpu_set_rate(rate);
c02e9630 AB	82	if (ret)
f54fe64d	83	return ret;
f54fe64d	84
c4dcc8a1 VK	85	cpufreq_generic_init(policy, &loongson2_clockmod_table[0], 0);
c4dcc8a1 VK	86	return 0;
f8ede0f7 WZ	87	}
f8ede0f7 WZ	88
f8ede0f7 WZ	89	static int loongson2_cpufreq_exit(struct cpufreq_policy *policy)
f8ede0f7 WZ	90	{
f8ede0f7 WZ	91	return 0;
	92	}
	93
f8ede0f7	94	static struct cpufreq_driver loongson2_cpufreq_driver = {
f8ede0f7 WZ	95	.name = "loongson2",
f8ede0f7 WZ	96	.init = loongson2_cpufreq_cpu_init,
6b0f8d73	97	.verify = cpufreq_generic_frequency_table_verify,
9c0ebcf7	98	.target_index = loongson2_cpufreq_target,
652ed95d	99	.get = cpufreq_generic_get,
f8ede0f7	100	.exit = loongson2_cpufreq_exit,
6b0f8d73	101	.attr = cpufreq_generic_attr,
f8ede0f7 WZ	102	};
f8ede0f7 WZ	103
a804d510	104	static const struct platform_device_id platform_device_ids[] = {
f8ede0f7 WZ	105	{
	106	.name = "loongson2_cpufreq",
	107	},
	108	{}
	109	};
	110
	111	MODULE_DEVICE_TABLE(platform, platform_device_ids);
	112
	113	static struct platform_driver platform_driver = {
	114	.driver = {
	115	.name = "loongson2_cpufreq",
f8ede0f7 WZ	116	},
	117	.id_table = platform_device_ids,
	118	};
	119
95cf1468 RB	120	/*
	121	* This is the simple version of Loongson-2 wait, Maybe we need do this in
	122	* interrupt disabled context.
	123	*/
	124
	125	static DEFINE_SPINLOCK(loongson2_wait_lock);
	126
	127	static void loongson2_cpu_wait(void)
	128	{
	129	unsigned long flags;
	130	u32 cpu_freq;
	131
	132	spin_lock_irqsave(&loongson2_wait_lock, flags);
1250c1a5 AO	133	cpu_freq = readl(LOONGSON_CHIPCFG);
	134	/* Put CPU into wait mode */
	135	writel(readl(LOONGSON_CHIPCFG) & ~0x7, LOONGSON_CHIPCFG);
	136	/* Restore CPU state */
	137	writel(cpu_freq, LOONGSON_CHIPCFG);
95cf1468	138	spin_unlock_irqrestore(&loongson2_wait_lock, flags);
fb40bc3e	139	local_irq_enable();
95cf1468 RB	140	}
95cf1468 RB	141
f8ede0f7 WZ	142	static int __init cpufreq_init(void)
	143	{
	144	int ret;
	145
	146	/* Register platform stuff */
	147	ret = platform_driver_register(&platform_driver);
	148	if (ret)
	149	return ret;
	150
1c5864e2	151	pr_info("Loongson-2F CPU frequency driver\n");
f8ede0f7 WZ	152
	153	cpufreq_register_notifier(&loongson2_cpufreq_notifier_block,
	154	CPUFREQ_TRANSITION_NOTIFIER);
	155
	156	ret = cpufreq_register_driver(&loongson2_cpufreq_driver);
	157
	158	if (!ret && !nowait) {
	159	saved_cpu_wait = cpu_wait;
	160	cpu_wait = loongson2_cpu_wait;
	161	}
	162
	163	return ret;
	164	}
	165
	166	static void __exit cpufreq_exit(void)
	167	{
	168	if (!nowait && saved_cpu_wait)
	169	cpu_wait = saved_cpu_wait;
	170	cpufreq_unregister_driver(&loongson2_cpufreq_driver);
	171	cpufreq_unregister_notifier(&loongson2_cpufreq_notifier_block,
	172	CPUFREQ_TRANSITION_NOTIFIER);
	173
	174	platform_driver_unregister(&platform_driver);
	175	}
	176
	177	module_init(cpufreq_init);
	178	module_exit(cpufreq_exit);
	179
	180	module_param(nowait, uint, 0644);
	181	MODULE_PARM_DESC(nowait, "Disable Loongson-2F specific wait");
	182
	183	MODULE_AUTHOR("Yanhua <yanh@lemote.com>");
	184	MODULE_DESCRIPTION("cpufreq driver for Loongson2F");
	185	MODULE_LICENSE("GPL");