[deliverable/linux.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/idle.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].driver_data) / 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;
	}

	/* 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);
	if (ret) {
		clk_put(cpuclk);
		return ret;
	}

	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 = {
	.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);
	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("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>
bdc92d74	21	#include <asm/idle.h>
f8ede0f7	22
95cf1468	23	#include <asm/mach-loongson/loongson.h>
f8ede0f7 WZ	24
	25	static uint nowait;
	26
	27	static struct clk *cpuclk;
	28
	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
	47	static unsigned int loongson2_cpufreq_get(unsigned int cpu)
	48	{
	49	return clk_get_rate(cpuclk);
	50	}
	51
	52	/*
	53	* Here we notify other drivers of the proposed change and the final change.
	54	*/
	55	static int loongson2_cpufreq_target(struct cpufreq_policy *policy,
	56	unsigned int target_freq,
	57	unsigned int relation)
	58	{
	59	unsigned int cpu = policy->cpu;
	60	unsigned int newstate = 0;
	61	cpumask_t cpus_allowed;
	62	struct cpufreq_freqs freqs;
	63	unsigned int freq;
	64
f8ede0f7	65	cpus_allowed = current->cpus_allowed;
ed1bbdef	66	set_cpus_allowed_ptr(current, cpumask_of(cpu));
f8ede0f7 WZ	67
	68	if (cpufreq_frequency_table_target
	69	(policy, &loongson2_clockmod_table[0], target_freq, relation,
	70	&newstate))
	71	return -EINVAL;
	72
	73	freq =
	74	((cpu_clock_freq / 1000) *
50701588	75	loongson2_clockmod_table[newstate].driver_data) / 8;
f8ede0f7 WZ	76	if (freq < policy->min \|\| freq > policy->max)
	77	return -EINVAL;
	78
	79	pr_debug("cpufreq: requested frequency %u Hz\n", target_freq * 1000);
	80
f8ede0f7 WZ	81	freqs.old = loongson2_cpufreq_get(cpu);
	82	freqs.new = freq;
	83	freqs.flags = 0;
	84
	85	if (freqs.new == freqs.old)
	86	return 0;
	87
	88	/* notifiers */
b43a7ffb	89	cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);
f8ede0f7	90
ed1bbdef	91	set_cpus_allowed_ptr(current, &cpus_allowed);
f8ede0f7 WZ	92
	93	/* setting the cpu frequency */
	94	clk_set_rate(cpuclk, freq);
	95
	96	/* notifiers */
b43a7ffb	97	cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);
f8ede0f7 WZ	98
	99	pr_debug("cpufreq: set frequency %u kHz\n", freq);
	100
	101	return 0;
	102	}
	103
	104	static int loongson2_cpufreq_cpu_init(struct cpufreq_policy *policy)
	105	{
	106	int i;
42913c79 JL	107	unsigned long rate;
42913c79 JL	108	int ret;
f8ede0f7	109
f8ede0f7 WZ	110	cpuclk = clk_get(NULL, "cpu_clk");
	111	if (IS_ERR(cpuclk)) {
	112	printk(KERN_ERR "cpufreq: couldn't get CPU clk\n");
	113	return PTR_ERR(cpuclk);
	114	}
	115
42913c79 JL	116	rate = cpu_clock_freq / 1000;
	117	if (!rate) {
	118	clk_put(cpuclk);
f8ede0f7	119	return -EINVAL;
42913c79	120	}
f8ede0f7 WZ	121
	122	/* clock table init */
	123	for (i = 2;
	124	(loongson2_clockmod_table[i].frequency != CPUFREQ_TABLE_END);
	125	i++)
42913c79	126	loongson2_clockmod_table[i].frequency = (rate * i) / 8;
f8ede0f7	127
f54fe64d AK	128	ret = clk_set_rate(cpuclk, rate);
	129	if (ret) {
	130	clk_put(cpuclk);
	131	return ret;
	132	}
	133
f8ede0f7 WZ	134	policy->cur = loongson2_cpufreq_get(policy->cpu);
	135
	136	cpufreq_frequency_table_get_attr(&loongson2_clockmod_table[0],
	137	policy->cpu);
	138
	139	return cpufreq_frequency_table_cpuinfo(policy,
	140	&loongson2_clockmod_table[0]);
	141	}
	142
	143	static int loongson2_cpufreq_verify(struct cpufreq_policy *policy)
	144	{
	145	return cpufreq_frequency_table_verify(policy,
	146	&loongson2_clockmod_table[0]);
	147	}
	148
	149	static int loongson2_cpufreq_exit(struct cpufreq_policy *policy)
	150	{
	151	clk_put(cpuclk);
	152	return 0;
	153	}
	154
	155	static struct freq_attr *loongson2_table_attr[] = {
	156	&cpufreq_freq_attr_scaling_available_freqs,
	157	NULL,
	158	};
	159
	160	static struct cpufreq_driver loongson2_cpufreq_driver = {
f8ede0f7 WZ	161	.name = "loongson2",
	162	.init = loongson2_cpufreq_cpu_init,
	163	.verify = loongson2_cpufreq_verify,
	164	.target = loongson2_cpufreq_target,
	165	.get = loongson2_cpufreq_get,
	166	.exit = loongson2_cpufreq_exit,
	167	.attr = loongson2_table_attr,
	168	};
	169
	170	static struct platform_device_id platform_device_ids[] = {
	171	{
	172	.name = "loongson2_cpufreq",
	173	},
	174	{}
	175	};
	176
	177	MODULE_DEVICE_TABLE(platform, platform_device_ids);
	178
	179	static struct platform_driver platform_driver = {
	180	.driver = {
	181	.name = "loongson2_cpufreq",
	182	.owner = THIS_MODULE,
	183	},
	184	.id_table = platform_device_ids,
	185	};
	186
95cf1468 RB	187	/*
	188	* This is the simple version of Loongson-2 wait, Maybe we need do this in
	189	* interrupt disabled context.
	190	*/
	191
	192	static DEFINE_SPINLOCK(loongson2_wait_lock);
	193
	194	static void loongson2_cpu_wait(void)
	195	{
	196	unsigned long flags;
	197	u32 cpu_freq;
	198
	199	spin_lock_irqsave(&loongson2_wait_lock, flags);
	200	cpu_freq = LOONGSON_CHIPCFG0;
70342287 RB	201	LOONGSON_CHIPCFG0 &= ~0x7; /* Put CPU into wait mode */
70342287 RB	202	LOONGSON_CHIPCFG0 = cpu_freq; /* Restore CPU state */
95cf1468	203	spin_unlock_irqrestore(&loongson2_wait_lock, flags);
fb40bc3e	204	local_irq_enable();
95cf1468 RB	205	}
95cf1468 RB	206
f8ede0f7 WZ	207	static int __init cpufreq_init(void)
	208	{
	209	int ret;
	210
	211	/* Register platform stuff */
	212	ret = platform_driver_register(&platform_driver);
	213	if (ret)
	214	return ret;
	215
	216	pr_info("cpufreq: Loongson-2F CPU frequency driver.\n");
	217
	218	cpufreq_register_notifier(&loongson2_cpufreq_notifier_block,
	219	CPUFREQ_TRANSITION_NOTIFIER);
	220
	221	ret = cpufreq_register_driver(&loongson2_cpufreq_driver);
	222
	223	if (!ret && !nowait) {
	224	saved_cpu_wait = cpu_wait;
	225	cpu_wait = loongson2_cpu_wait;
	226	}
	227
	228	return ret;
	229	}
	230
	231	static void __exit cpufreq_exit(void)
	232	{
	233	if (!nowait && saved_cpu_wait)
	234	cpu_wait = saved_cpu_wait;
	235	cpufreq_unregister_driver(&loongson2_cpufreq_driver);
	236	cpufreq_unregister_notifier(&loongson2_cpufreq_notifier_block,
	237	CPUFREQ_TRANSITION_NOTIFIER);
	238
	239	platform_driver_unregister(&platform_driver);
	240	}
	241
	242	module_init(cpufreq_init);
	243	module_exit(cpufreq_exit);
	244
	245	module_param(nowait, uint, 0644);
	246	MODULE_PARM_DESC(nowait, "Disable Loongson-2F specific wait");
	247
	248	MODULE_AUTHOR("Yanhua <yanh@lemote.com>");
	249	MODULE_DESCRIPTION("cpufreq driver for Loongson2F");
	250	MODULE_LICENSE("GPL");