[linux-block.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. & Insititute 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.
 */
#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/mach-loongson/loongson.h>

static uint nowait;

static struct clk *cpuclk;

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;
}

static unsigned int loongson2_cpufreq_get(unsigned int cpu)
{
	return clk_get_rate(cpuclk);
}

/*
 * Here we notify other drivers of the proposed change and the final change.
 */
static int loongson2_cpufreq_target(struct cpufreq_policy *policy,
				     unsigned int target_freq,
				     unsigned int relation)
{
	unsigned int cpu = policy->cpu;
	unsigned int newstate = 0;
	cpumask_t cpus_allowed;
	struct cpufreq_freqs freqs;
	unsigned int freq;

	cpus_allowed = current->cpus_allowed;
	set_cpus_allowed_ptr(current, cpumask_of(cpu));

	if (cpufreq_frequency_table_target
	    (policy, &loongson2_clockmod_table[0], target_freq, relation,
	     &newstate))
		return -EINVAL;

	freq =
	    ((cpu_clock_freq / 1000) *
	     loongson2_clockmod_table[newstate].index) / 8;
	if (freq < policy->min || freq > policy->max)
		return -EINVAL;

	pr_debug("cpufreq: requested frequency %u Hz\n", target_freq * 1000);

	freqs.old = loongson2_cpufreq_get(cpu);
	freqs.new = freq;
	freqs.flags = 0;

	if (freqs.new == freqs.old)
		return 0;

	/* notifiers */
	cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);

	set_cpus_allowed_ptr(current, &cpus_allowed);

	/* setting the cpu frequency */
	clk_set_rate(cpuclk, freq);

	/* notifiers */
	cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);

	pr_debug("cpufreq: set frequency %u kHz\n", freq);

	return 0;
}

static int loongson2_cpufreq_cpu_init(struct cpufreq_policy *policy)
{
	int i;
	unsigned long rate;
	int ret;

	cpuclk = clk_get(NULL, "cpu_clk");
	if (IS_ERR(cpuclk)) {
		printk(KERN_ERR "cpufreq: couldn't get CPU clk\n");
		return PTR_ERR(cpuclk);
	}

	rate = cpu_clock_freq / 1000;
	if (!rate) {
		clk_put(cpuclk);
		return -EINVAL;
	}
	ret = clk_set_rate(cpuclk, rate);
	if (ret) {
		clk_put(cpuclk);
		return ret;
	}

	/* clock table init */
	for (i = 2;
	     (loongson2_clockmod_table[i].frequency != CPUFREQ_TABLE_END);
	     i++)
		loongson2_clockmod_table[i].frequency = (rate * i) / 8;

	policy->cur = loongson2_cpufreq_get(policy->cpu);

	cpufreq_frequency_table_get_attr(&loongson2_clockmod_table[0],
					 policy->cpu);

	return cpufreq_frequency_table_cpuinfo(policy,
					    &loongson2_clockmod_table[0]);
}

static int loongson2_cpufreq_verify(struct cpufreq_policy *policy)
{
	return cpufreq_frequency_table_verify(policy,
					      &loongson2_clockmod_table[0]);
}

static int loongson2_cpufreq_exit(struct cpufreq_policy *policy)
{
	clk_put(cpuclk);
	return 0;
}

static struct freq_attr *loongson2_table_attr[] = {
	&cpufreq_freq_attr_scaling_available_freqs,
	NULL,
};

static struct cpufreq_driver loongson2_cpufreq_driver = {
	.owner = THIS_MODULE,
	.name = "loongson2",
	.init = loongson2_cpufreq_cpu_init,
	.verify = loongson2_cpufreq_verify,
	.target = loongson2_cpufreq_target,
	.get = loongson2_cpufreq_get,
	.exit = loongson2_cpufreq_exit,
	.attr = loongson2_table_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",
		.owner = THIS_MODULE,
	},
	.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_CHIPCFG0;
	LOONGSON_CHIPCFG0 &= ~0x7;	/* Put CPU into wait mode */
	LOONGSON_CHIPCFG0 = cpu_freq;	/* Restore CPU state */
	spin_unlock_irqrestore(&loongson2_wait_lock, flags);
}

static int __init cpufreq_init(void)
{
	int ret;

	/* Register platform stuff */
	ret = platform_driver_register(&platform_driver);
	if (ret)
		return ret;

	pr_info("cpufreq: 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	*
	6	* Copyright (C) 2006 - 2008 Lemote Inc. & Insititute of Computing Technology
	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	*/
	13	#include <linux/cpufreq.h>
	14	#include <linux/module.h>
	15	#include <linux/err.h>
	16	#include <linux/sched.h> /* set_cpus_allowed() */
	17	#include <linux/delay.h>
	18	#include <linux/platform_device.h>
	19
	20	#include <asm/clock.h>
	21
95cf1468	22	#include <asm/mach-loongson/loongson.h>
f8ede0f7 WZ	23
	24	static uint nowait;
	25
	26	static struct clk *cpuclk;
	27
	28	static void (*saved_cpu_wait) (void);
	29
	30	static int loongson2_cpu_freq_notifier(struct notifier_block *nb,
	31	unsigned long val, void *data);
	32
	33	static struct notifier_block loongson2_cpufreq_notifier_block = {
	34	.notifier_call = loongson2_cpu_freq_notifier
	35	};
	36
	37	static 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	static unsigned int loongson2_cpufreq_get(unsigned int cpu)
	47	{
	48	return clk_get_rate(cpuclk);
	49	}
	50
	51	/*
	52	* Here we notify other drivers of the proposed change and the final change.
	53	*/
	54	static int loongson2_cpufreq_target(struct cpufreq_policy *policy,
	55	unsigned int target_freq,
	56	unsigned int relation)
	57	{
	58	unsigned int cpu = policy->cpu;
	59	unsigned int newstate = 0;
	60	cpumask_t cpus_allowed;
	61	struct cpufreq_freqs freqs;
	62	unsigned int freq;
	63
f8ede0f7	64	cpus_allowed = current->cpus_allowed;
ed1bbdef	65	set_cpus_allowed_ptr(current, cpumask_of(cpu));
f8ede0f7 WZ	66
	67	if (cpufreq_frequency_table_target
	68	(policy, &loongson2_clockmod_table[0], target_freq, relation,
	69	&newstate))
	70	return -EINVAL;
	71
	72	freq =
	73	((cpu_clock_freq / 1000) *
	74	loongson2_clockmod_table[newstate].index) / 8;
	75	if (freq < policy->min \|\| freq > policy->max)
	76	return -EINVAL;
	77
	78	pr_debug("cpufreq: requested frequency %u Hz\n", target_freq * 1000);
	79
f8ede0f7 WZ	80	freqs.old = loongson2_cpufreq_get(cpu);
	81	freqs.new = freq;
	82	freqs.flags = 0;
	83
	84	if (freqs.new == freqs.old)
	85	return 0;
	86
	87	/* notifiers */
b43a7ffb	88	cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);
f8ede0f7	89
ed1bbdef	90	set_cpus_allowed_ptr(current, &cpus_allowed);
f8ede0f7 WZ	91
	92	/* setting the cpu frequency */
	93	clk_set_rate(cpuclk, freq);
	94
	95	/* notifiers */
b43a7ffb	96	cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);
f8ede0f7 WZ	97
	98	pr_debug("cpufreq: set frequency %u kHz\n", freq);
	99
	100	return 0;
	101	}
	102
	103	static int loongson2_cpufreq_cpu_init(struct cpufreq_policy *policy)
	104	{
	105	int i;
42913c79 JL	106	unsigned long rate;
42913c79 JL	107	int ret;
f8ede0f7	108
f8ede0f7 WZ	109	cpuclk = clk_get(NULL, "cpu_clk");
	110	if (IS_ERR(cpuclk)) {
	111	printk(KERN_ERR "cpufreq: couldn't get CPU clk\n");
	112	return PTR_ERR(cpuclk);
	113	}
	114
42913c79 JL	115	rate = cpu_clock_freq / 1000;
	116	if (!rate) {
	117	clk_put(cpuclk);
f8ede0f7	118	return -EINVAL;
42913c79 JL	119	}
	120	ret = clk_set_rate(cpuclk, rate);
	121	if (ret) {
	122	clk_put(cpuclk);
	123	return ret;
	124	}
f8ede0f7 WZ	125
	126	/* clock table init */
	127	for (i = 2;
	128	(loongson2_clockmod_table[i].frequency != CPUFREQ_TABLE_END);
	129	i++)
42913c79	130	loongson2_clockmod_table[i].frequency = (rate * i) / 8;
f8ede0f7 WZ	131
	132	policy->cur = loongson2_cpufreq_get(policy->cpu);
	133
	134	cpufreq_frequency_table_get_attr(&loongson2_clockmod_table[0],
	135	policy->cpu);
	136
	137	return cpufreq_frequency_table_cpuinfo(policy,
	138	&loongson2_clockmod_table[0]);
	139	}
	140
	141	static int loongson2_cpufreq_verify(struct cpufreq_policy *policy)
	142	{
	143	return cpufreq_frequency_table_verify(policy,
	144	&loongson2_clockmod_table[0]);
	145	}
	146
	147	static int loongson2_cpufreq_exit(struct cpufreq_policy *policy)
	148	{
	149	clk_put(cpuclk);
	150	return 0;
	151	}
	152
	153	static struct freq_attr *loongson2_table_attr[] = {
	154	&cpufreq_freq_attr_scaling_available_freqs,
	155	NULL,
	156	};
	157
	158	static struct cpufreq_driver loongson2_cpufreq_driver = {
	159	.owner = THIS_MODULE,
	160	.name = "loongson2",
	161	.init = loongson2_cpufreq_cpu_init,
	162	.verify = loongson2_cpufreq_verify,
	163	.target = loongson2_cpufreq_target,
	164	.get = loongson2_cpufreq_get,
	165	.exit = loongson2_cpufreq_exit,
	166	.attr = loongson2_table_attr,
	167	};
	168
	169	static struct platform_device_id platform_device_ids[] = {
	170	{
	171	.name = "loongson2_cpufreq",
	172	},
	173	{}
	174	};
	175
	176	MODULE_DEVICE_TABLE(platform, platform_device_ids);
	177
	178	static struct platform_driver platform_driver = {
	179	.driver = {
	180	.name = "loongson2_cpufreq",
	181	.owner = THIS_MODULE,
	182	},
	183	.id_table = platform_device_ids,
	184	};
	185
95cf1468 RB	186	/*
	187	* This is the simple version of Loongson-2 wait, Maybe we need do this in
	188	* interrupt disabled context.
	189	*/
	190
	191	static DEFINE_SPINLOCK(loongson2_wait_lock);
	192
	193	static void loongson2_cpu_wait(void)
	194	{
	195	unsigned long flags;
	196	u32 cpu_freq;
	197
	198	spin_lock_irqsave(&loongson2_wait_lock, flags);
	199	cpu_freq = LOONGSON_CHIPCFG0;
70342287 RB	200	LOONGSON_CHIPCFG0 &= ~0x7; /* Put CPU into wait mode */
70342287 RB	201	LOONGSON_CHIPCFG0 = cpu_freq; /* Restore CPU state */
95cf1468 RB	202	spin_unlock_irqrestore(&loongson2_wait_lock, flags);
	203	}
	204
f8ede0f7 WZ	205	static int __init cpufreq_init(void)
	206	{
	207	int ret;
	208
	209	/* Register platform stuff */
	210	ret = platform_driver_register(&platform_driver);
	211	if (ret)
	212	return ret;
	213
	214	pr_info("cpufreq: Loongson-2F CPU frequency driver.\n");
	215
	216	cpufreq_register_notifier(&loongson2_cpufreq_notifier_block,
	217	CPUFREQ_TRANSITION_NOTIFIER);
	218
	219	ret = cpufreq_register_driver(&loongson2_cpufreq_driver);
	220
	221	if (!ret && !nowait) {
	222	saved_cpu_wait = cpu_wait;
	223	cpu_wait = loongson2_cpu_wait;
	224	}
	225
	226	return ret;
	227	}
	228
	229	static void __exit cpufreq_exit(void)
	230	{
	231	if (!nowait && saved_cpu_wait)
	232	cpu_wait = saved_cpu_wait;
	233	cpufreq_unregister_driver(&loongson2_cpufreq_driver);
	234	cpufreq_unregister_notifier(&loongson2_cpufreq_notifier_block,
	235	CPUFREQ_TRANSITION_NOTIFIER);
	236
	237	platform_driver_unregister(&platform_driver);
	238	}
	239
	240	module_init(cpufreq_init);
	241	module_exit(cpufreq_exit);
	242
	243	module_param(nowait, uint, 0644);
	244	MODULE_PARM_DESC(nowait, "Disable Loongson-2F specific wait");
	245
	246	MODULE_AUTHOR("Yanhua <yanh@lemote.com>");
	247	MODULE_DESCRIPTION("cpufreq driver for Loongson2F");
	248	MODULE_LICENSE("GPL");