[mirror_ubuntu-zesty-kernel.git] / drivers / cpufreq / at32ap-cpufreq.c

/*
 * Copyright (C) 2004-2007 Atmel Corporation
 *
 * Based on MIPS implementation arch/mips/kernel/time.c
 *   Copyright 2001 MontaVista Software Inc.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

/*#define DEBUG*/

#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/init.h>
#include <linux/cpufreq.h>
#include <linux/io.h>
#include <linux/clk.h>
#include <linux/err.h>
#include <linux/export.h>
#include <linux/slab.h>

static struct clk *cpuclk;
static struct cpufreq_frequency_table *freq_table;

static unsigned int at32_get_speed(unsigned int cpu)
{
	/* No SMP support */
	if (cpu)
		return 0;
	return (unsigned int)((clk_get_rate(cpuclk) + 500) / 1000);
}

static unsigned int	ref_freq;
static unsigned long	loops_per_jiffy_ref;

static int at32_set_target(struct cpufreq_policy *policy, unsigned int index)
{
	struct cpufreq_freqs freqs;

	freqs.old = at32_get_speed(0);
	freqs.new = freq_table[index].frequency;

	if (!ref_freq) {
		ref_freq = freqs.old;
		loops_per_jiffy_ref = boot_cpu_data.loops_per_jiffy;
	}

	cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);
	if (freqs.old < freqs.new)
		boot_cpu_data.loops_per_jiffy = cpufreq_scale(
				loops_per_jiffy_ref, ref_freq, freqs.new);
	clk_set_rate(cpuclk, freqs.new * 1000);
	if (freqs.new < freqs.old)
		boot_cpu_data.loops_per_jiffy = cpufreq_scale(
				loops_per_jiffy_ref, ref_freq, freqs.new);
	cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);

	pr_debug("cpufreq: set frequency %u Hz\n", freqs.new * 1000);

	return 0;
}

static int __init at32_cpufreq_driver_init(struct cpufreq_policy *policy)
{
	unsigned int frequency, rate, min_freq;
	int retval, steps, i;

	if (policy->cpu != 0)
		return -EINVAL;

	cpuclk = clk_get(NULL, "cpu");
	if (IS_ERR(cpuclk)) {
		pr_debug("cpufreq: could not get CPU clk\n");
		retval = PTR_ERR(cpuclk);
		goto out_err;
	}

	min_freq = (clk_round_rate(cpuclk, 1) + 500) / 1000;
	frequency = (clk_round_rate(cpuclk, ~0UL) + 500) / 1000;
	policy->cpuinfo.transition_latency = 0;

	/*
	 * AVR32 CPU frequency rate scales in power of two between maximum and
	 * minimum, also add space for the table end marker.
	 *
	 * Further validate that the frequency is usable, and append it to the
	 * frequency table.
	 */
	steps = fls(frequency / min_freq) + 1;
	freq_table = kzalloc(steps * sizeof(struct cpufreq_frequency_table),
			GFP_KERNEL);
	if (!freq_table) {
		retval = -ENOMEM;
		goto out_err_put_clk;
	}

	for (i = 0; i < (steps - 1); i++) {
		rate = clk_round_rate(cpuclk, frequency * 1000) / 1000;

		if (rate != frequency)
			freq_table[i].frequency = CPUFREQ_ENTRY_INVALID;
		else
			freq_table[i].frequency = frequency;

		frequency /= 2;
	}

	freq_table[steps - 1].frequency = CPUFREQ_TABLE_END;

	retval = cpufreq_table_validate_and_show(policy, freq_table);
	if (!retval) {
		printk("cpufreq: AT32AP CPU frequency driver\n");
		return 0;
	}

	kfree(freq_table);
out_err_put_clk:
	clk_put(cpuclk);
out_err:
	return retval;
}

static struct cpufreq_driver at32_driver = {
	.name		= "at32ap",
	.init		= at32_cpufreq_driver_init,
	.verify		= cpufreq_generic_frequency_table_verify,
	.target_index	= at32_set_target,
	.get		= at32_get_speed,
	.flags		= CPUFREQ_STICKY,
};

static int __init at32_cpufreq_init(void)
{
	return cpufreq_register_driver(&at32_driver);
}
late_initcall(at32_cpufreq_init);
Commit	Line	Data
9e58e185 HCE	1	/*
	2	* Copyright (C) 2004-2007 Atmel Corporation
	3	*
	4	* Based on MIPS implementation arch/mips/kernel/time.c
	5	* Copyright 2001 MontaVista Software Inc.
	6	*
	7	* This program is free software; you can redistribute it and/or modify
	8	* it under the terms of the GNU General Public License version 2 as
	9	* published by the Free Software Foundation.
	10	*/
	11
	12	/#define DEBUG/
	13
	14	#include <linux/kernel.h>
	15	#include <linux/types.h>
	16	#include <linux/init.h>
	17	#include <linux/cpufreq.h>
	18	#include <linux/io.h>
	19	#include <linux/clk.h>
	20	#include <linux/err.h>
09cf6a29	21	#include <linux/export.h>
848cb944	22	#include <linux/slab.h>
9e58e185 HCE	23
9e58e185 HCE	24	static struct clk *cpuclk;
848cb944	25	static struct cpufreq_frequency_table *freq_table;
9e58e185	26
9e58e185 HCE	27	static unsigned int at32_get_speed(unsigned int cpu)
	28	{
	29	/* No SMP support */
	30	if (cpu)
	31	return 0;
	32	return (unsigned int)((clk_get_rate(cpuclk) + 500) / 1000);
	33	}
	34
e3f91ca4 HS	35	static unsigned int ref_freq;
	36	static unsigned long loops_per_jiffy_ref;
	37
9c0ebcf7	38	static int at32_set_target(struct cpufreq_policy *policy, unsigned int index)
9e58e185 HCE	39	{
9e58e185 HCE	40	struct cpufreq_freqs freqs;
9e58e185 HCE	41
9e58e185 HCE	42	freqs.old = at32_get_speed(0);
9c0ebcf7	43	freqs.new = freq_table[index].frequency;
9e58e185	44
e3f91ca4 HS	45	if (!ref_freq) {
	46	ref_freq = freqs.old;
	47	loops_per_jiffy_ref = boot_cpu_data.loops_per_jiffy;
	48	}
	49
b43a7ffb	50	cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);
e3f91ca4 HS	51	if (freqs.old < freqs.new)
	52	boot_cpu_data.loops_per_jiffy = cpufreq_scale(
	53	loops_per_jiffy_ref, ref_freq, freqs.new);
9c0ebcf7	54	clk_set_rate(cpuclk, freqs.new * 1000);
e3f91ca4 HS	55	if (freqs.new < freqs.old)
	56	boot_cpu_data.loops_per_jiffy = cpufreq_scale(
	57	loops_per_jiffy_ref, ref_freq, freqs.new);
b43a7ffb	58	cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);
9e58e185	59
9c0ebcf7	60	pr_debug("cpufreq: set frequency %u Hz\n", freqs.new * 1000);
9e58e185 HCE	61
	62	return 0;
	63	}
	64
	65	static int __init at32_cpufreq_driver_init(struct cpufreq_policy *policy)
	66	{
017189b5	67	unsigned int frequency, rate, min_freq;
848cb944 HCE	68	int retval, steps, i;
848cb944 HCE	69
9e58e185 HCE	70	if (policy->cpu != 0)
	71	return -EINVAL;
	72
	73	cpuclk = clk_get(NULL, "cpu");
	74	if (IS_ERR(cpuclk)) {
	75	pr_debug("cpufreq: could not get CPU clk\n");
848cb944 HCE	76	retval = PTR_ERR(cpuclk);
848cb944 HCE	77	goto out_err;
9e58e185 HCE	78	}
9e58e185 HCE	79
017189b5 VK	80	min_freq = (clk_round_rate(cpuclk, 1) + 500) / 1000;
017189b5 VK	81	frequency = (clk_round_rate(cpuclk, ~0UL) + 500) / 1000;
9e58e185	82	policy->cpuinfo.transition_latency = 0;
9e58e185	83
848cb944 HCE	84	/*
	85	* AVR32 CPU frequency rate scales in power of two between maximum and
	86	* minimum, also add space for the table end marker.
	87	*
	88	* Further validate that the frequency is usable, and append it to the
	89	* frequency table.
	90	*/
017189b5	91	steps = fls(frequency / min_freq) + 1;
848cb944 HCE	92	freq_table = kzalloc(steps * sizeof(struct cpufreq_frequency_table),
	93	GFP_KERNEL);
	94	if (!freq_table) {
	95	retval = -ENOMEM;
	96	goto out_err_put_clk;
	97	}
9e58e185	98
848cb944 HCE	99	for (i = 0; i < (steps - 1); i++) {
	100	rate = clk_round_rate(cpuclk, frequency * 1000) / 1000;
	101
	102	if (rate != frequency)
	103	freq_table[i].frequency = CPUFREQ_ENTRY_INVALID;
	104	else
	105	freq_table[i].frequency = frequency;
	106
	107	frequency /= 2;
	108	}
	109
	110	freq_table[steps - 1].frequency = CPUFREQ_TABLE_END;
	111
	112	retval = cpufreq_table_validate_and_show(policy, freq_table);
	113	if (!retval) {
	114	printk("cpufreq: AT32AP CPU frequency driver\n");
	115	return 0;
	116	}
	117
	118	kfree(freq_table);
	119	out_err_put_clk:
	120	clk_put(cpuclk);
	121	out_err:
	122	return retval;
9e58e185 HCE	123	}
	124
	125	static struct cpufreq_driver at32_driver = {
	126	.name = "at32ap",
9e58e185	127	.init = at32_cpufreq_driver_init,
5ae68f47	128	.verify = cpufreq_generic_frequency_table_verify,
9c0ebcf7	129	.target_index = at32_set_target,
9e58e185 HCE	130	.get = at32_get_speed,
	131	.flags = CPUFREQ_STICKY,
	132	};
	133
	134	static int __init at32_cpufreq_init(void)
	135	{
	136	return cpufreq_register_driver(&at32_driver);
	137	}
f04d264a	138	late_initcall(at32_cpufreq_init);