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
|
/*
* 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 int at32_verify_speed(struct cpufreq_policy *policy)
{
if (policy->cpu != 0)
return -EINVAL;
cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq,
policy->cpuinfo.max_freq);
return 0;
}
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 target_freq,
unsigned int relation)
{
struct cpufreq_freqs freqs;
long freq;
/* Convert target_freq from kHz to Hz */
freq = clk_round_rate(cpuclk, target_freq * 1000);
/* Check if policy->min <= new_freq <= policy->max */
if(freq < (policy->min * 1000) || freq > (policy->max * 1000))
return -EINVAL;
pr_debug("cpufreq: requested frequency %u Hz\n", target_freq * 1000);
freqs.old = at32_get_speed(0);
freqs.new = (freq + 500) / 1000;
freqs.flags = 0;
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, freq);
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 %lu Hz\n", freq);
return 0;
}
static int __init at32_cpufreq_driver_init(struct cpufreq_policy *policy)
{
unsigned int frequency, rate;
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;
}
policy->cpuinfo.min_freq = (clk_round_rate(cpuclk, 1) + 500) / 1000;
policy->cpuinfo.max_freq = (clk_round_rate(cpuclk, ~0UL) + 500) / 1000;
policy->cpuinfo.transition_latency = 0;
policy->cur = at32_get_speed(0);
policy->min = policy->cpuinfo.min_freq;
policy->max = policy->cpuinfo.max_freq;
/*
* 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(policy->cpuinfo.max_freq / policy->cpuinfo.min_freq) + 1;
freq_table = kzalloc(steps * sizeof(struct cpufreq_frequency_table),
GFP_KERNEL);
if (!freq_table) {
retval = -ENOMEM;
goto out_err_put_clk;
}
frequency = policy->cpuinfo.max_freq;
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 = at32_verify_speed,
.target = 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);
|
