aboutsummaryrefslogtreecommitdiff
path: root/arch/arm/plat-omap/cpu-omap.c
blob: 341235c278acbdcffe93a61387832a2f3e74e053 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
/*
 *  linux/arch/arm/plat-omap/cpu-omap.c
 *
 *  CPU frequency scaling for OMAP
 *
 *  Copyright (C) 2005 Nokia Corporation
 *  Written by Tony Lindgren <tony@atomide.com>
 *
 *  Based on cpu-sa1110.c, Copyright (C) 2001 Russell King
 *
 * 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.
 */
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/cpufreq.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/err.h>
#include <linux/clk.h>
#include <linux/io.h>

#include <mach/hardware.h>
#include <mach/clock.h>
#include <asm/system.h>

#define VERY_HI_RATE	900000000

static struct cpufreq_frequency_table *freq_table;

#ifdef CONFIG_ARCH_OMAP1
#define MPU_CLK		"mpu"
#else
#define MPU_CLK		"virt_prcm_set"
#endif

static struct clk *mpu_clk;

/* TODO: Add support for SDRAM timing changes */

int omap_verify_speed(struct cpufreq_policy *policy)
{
	if (freq_table)
		return cpufreq_frequency_table_verify(policy, freq_table);

	if (policy->cpu)
		return -EINVAL;

	cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq,
				     policy->cpuinfo.max_freq);

	policy->min = clk_round_rate(mpu_clk, policy->min * 1000) / 1000;
	policy->max = clk_round_rate(mpu_clk, policy->max * 1000) / 1000;
	cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq,
				     policy->cpuinfo.max_freq);
	return 0;
}

unsigned int omap_getspeed(unsigned int cpu)
{
	unsigned long rate;

	if (cpu)
		return 0;

	rate = clk_get_rate(mpu_clk) / 1000;
	return rate;
}

static int omap_target(struct cpufreq_policy *policy,
		       unsigned int target_freq,
		       unsigned int relation)
{
	struct cpufreq_freqs freqs;
	int ret = 0;

	/* Ensure desired rate is within allowed range.  Some govenors
	 * (ondemand) will just pass target_freq=0 to get the minimum. */
	if (target_freq < policy->min)
		target_freq = policy->min;
	if (target_freq > policy->max)
		target_freq = policy->max;

	freqs.old = omap_getspeed(0);
	freqs.new = clk_round_rate(mpu_clk, target_freq * 1000) / 1000;
	freqs.cpu = 0;

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

	cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
#ifdef CONFIG_CPU_FREQ_DEBUG
	printk(KERN_DEBUG "cpufreq-omap: transition: %u --> %u\n",
	       freqs.old, freqs.new);
#endif
	ret = clk_set_rate(mpu_clk, freqs.new * 1000);
	cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);

	return ret;
}

static int __init omap_cpu_init(struct cpufreq_policy *policy)
{
	int result = 0;

	mpu_clk = clk_get(NULL, MPU_CLK);
	if (IS_ERR(mpu_clk))
		return PTR_ERR(mpu_clk);

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

	policy->cur = policy->min = policy->max = omap_getspeed(0);

	clk_init_cpufreq_table(&freq_table);
	if (freq_table) {
		result = cpufreq_frequency_table_cpuinfo(policy, freq_table);
		if (!result)
			cpufreq_frequency_table_get_attr(freq_table,
							policy->cpu);
	} else {
		policy->cpuinfo.min_freq = clk_round_rate(mpu_clk, 0) / 1000;
		policy->cpuinfo.max_freq = clk_round_rate(mpu_clk,
							VERY_HI_RATE) / 1000;
	}

	/* FIXME: what's the actual transition time? */
	policy->cpuinfo.transition_latency = 300 * 1000;

	return 0;
}

static int omap_cpu_exit(struct cpufreq_policy *policy)
{
	clk_put(mpu_clk);
	return 0;
}

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

static struct cpufreq_driver omap_driver = {
	.flags		= CPUFREQ_STICKY,
	.verify		= omap_verify_speed,
	.target		= omap_target,
	.get		= omap_getspeed,
	.init		= omap_cpu_init,
	.exit		= omap_cpu_exit,
	.name		= "omap",
	.attr		= omap_cpufreq_attr,
};

static int __init omap_cpufreq_init(void)
{
	return cpufreq_register_driver(&omap_driver);
}

arch_initcall(omap_cpufreq_init);

/*
 * if ever we want to remove this, upon cleanup call:
 *
 * cpufreq_unregister_driver()
 * cpufreq_frequency_table_put_attr()
 */