summaryrefslogtreecommitdiffstats
path: root/drivers/cpufreq/db8500-cpufreq.c
blob: d90456a809f9cb8cf92d7daf11e3efbf25f18917 (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
/*
 * Copyright (C) STMicroelectronics 2009
 * Copyright (C) ST-Ericsson SA 2010
 *
 * License Terms: GNU General Public License v2
 * Author: Sundar Iyer <sundar.iyer@stericsson.com>
 * Author: Martin Persson <martin.persson@stericsson.com>
 * Author: Jonas Aaberg <jonas.aberg@stericsson.com>
 *
 */
#include <linux/kernel.h>
#include <linux/cpufreq.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/mfd/db8500-prcmu.h>
#include <mach/id.h>

static struct cpufreq_frequency_table freq_table[] = {
	[0] = {
		.index = 0,
		.frequency = 300000,
	},
	[1] = {
		.index = 1,
		.frequency = 600000,
	},
	[2] = {
		/* Used for MAX_OPP, if available */
		.index = 2,
		.frequency = CPUFREQ_TABLE_END,
	},
	[3] = {
		.index = 3,
		.frequency = CPUFREQ_TABLE_END,
	},
};

static enum arm_opp idx2opp[] = {
	ARM_50_OPP,
	ARM_100_OPP,
	ARM_MAX_OPP
};

static struct freq_attr *db8500_cpufreq_attr[] = {
	&cpufreq_freq_attr_scaling_available_freqs,
	NULL,
};

static int db8500_cpufreq_verify_speed(struct cpufreq_policy *policy)
{
	return cpufreq_frequency_table_verify(policy, freq_table);
}

static int db8500_cpufreq_target(struct cpufreq_policy *policy,
				unsigned int target_freq,
				unsigned int relation)
{
	struct cpufreq_freqs freqs;
	unsigned int idx;

	/* scale the target frequency to one of the extremes supported */
	if (target_freq < policy->cpuinfo.min_freq)
		target_freq = policy->cpuinfo.min_freq;
	if (target_freq > policy->cpuinfo.max_freq)
		target_freq = policy->cpuinfo.max_freq;

	/* Lookup the next frequency */
	if (cpufreq_frequency_table_target
	    (policy, freq_table, target_freq, relation, &idx)) {
		return -EINVAL;
	}

	freqs.old = policy->cur;
	freqs.new = freq_table[idx].frequency;
	freqs.cpu = policy->cpu;

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

	/* pre-change notification */
	cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);

	/* request the PRCM unit for opp change */
	if (prcmu_set_arm_opp(idx2opp[idx])) {
		pr_err("db8500-cpufreq:  Failed to set OPP level\n");
		return -EINVAL;
	}

	/* post change notification */
	cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);

	return 0;
}

static unsigned int db8500_cpufreq_getspeed(unsigned int cpu)
{
	int i;
	/* request the prcm to get the current ARM opp */
	for (i = 0; prcmu_get_arm_opp() != idx2opp[i]; i++)
		;
	return freq_table[i].frequency;
}

static int __cpuinit db8500_cpufreq_init(struct cpufreq_policy *policy)
{
	int res;
	int i;

	BUILD_BUG_ON(ARRAY_SIZE(idx2opp) + 1 != ARRAY_SIZE(freq_table));

	if (cpu_is_u8500v2() && !prcmu_is_u8400()) {
		freq_table[0].frequency = 400000;
		freq_table[1].frequency = 800000;
		if (prcmu_has_arm_maxopp())
			freq_table[2].frequency = 1000000;
	}

	/* get policy fields based on the table */
	res = cpufreq_frequency_table_cpuinfo(policy, freq_table);
	if (!res)
		cpufreq_frequency_table_get_attr(freq_table, policy->cpu);
	else {
		pr_err("db8500-cpufreq : Failed to read policy table\n");
		return res;
	}

	policy->min = policy->cpuinfo.min_freq;
	policy->max = policy->cpuinfo.max_freq;
	policy->cur = db8500_cpufreq_getspeed(policy->cpu);

	for (i = 0; freq_table[i].frequency != policy->cur; i++)
		;

	policy->governor = CPUFREQ_DEFAULT_GOVERNOR;

	/*
	 * FIXME : Need to take time measurement across the target()
	 *	   function with no/some/all drivers in the notification
	 *	   list.
	 */
	policy->cpuinfo.transition_latency = 20 * 1000; /* in ns */

	/* policy sharing between dual CPUs */
	cpumask_copy(policy->cpus, &cpu_present_map);

	policy->shared_type = CPUFREQ_SHARED_TYPE_ALL;

	return 0;
}

static struct cpufreq_driver db8500_cpufreq_driver = {
	.flags  = CPUFREQ_STICKY,
	.verify = db8500_cpufreq_verify_speed,
	.target = db8500_cpufreq_target,
	.get    = db8500_cpufreq_getspeed,
	.init   = db8500_cpufreq_init,
	.name   = "DB8500",
	.attr   = db8500_cpufreq_attr,
};

static int __init db8500_cpufreq_register(void)
{
	if (!cpu_is_u8500v20_or_later())
		return -ENODEV;

	pr_info("cpufreq for DB8500 started\n");
	return cpufreq_register_driver(&db8500_cpufreq_driver);
}
device_initcall(db8500_cpufreq_register);
OpenPOWER on IntegriCloud