Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
1/*
2 * cpufreq driver for the SuperH processors.
3 *
4 * Copyright (C) 2002 - 2012 Paul Mundt
5 * Copyright (C) 2002 M. R. Brown
6 *
7 * Clock framework bits from arch/avr32/mach-at32ap/cpufreq.c
8 *
9 * Copyright (C) 2004-2007 Atmel Corporation
10 *
11 * This file is subject to the terms and conditions of the GNU General Public
12 * License. See the file "COPYING" in the main directory of this archive
13 * for more details.
14 */
15#define pr_fmt(fmt) "cpufreq: " fmt
16
17#include <linux/types.h>
18#include <linux/cpufreq.h>
19#include <linux/kernel.h>
20#include <linux/module.h>
21#include <linux/init.h>
22#include <linux/err.h>
23#include <linux/cpumask.h>
24#include <linux/cpu.h>
25#include <linux/smp.h>
26#include <linux/clk.h>
27#include <linux/percpu.h>
28#include <linux/sh_clk.h>
29
30static DEFINE_PER_CPU(struct clk, sh_cpuclk);
31
32struct cpufreq_target {
33 struct cpufreq_policy *policy;
34 unsigned int freq;
35};
36
37static unsigned int sh_cpufreq_get(unsigned int cpu)
38{
39 return (clk_get_rate(&per_cpu(sh_cpuclk, cpu)) + 500) / 1000;
40}
41
42static long __sh_cpufreq_target(void *arg)
43{
44 struct cpufreq_target *target = arg;
45 struct cpufreq_policy *policy = target->policy;
46 int cpu = policy->cpu;
47 struct clk *cpuclk = &per_cpu(sh_cpuclk, cpu);
48 struct cpufreq_freqs freqs;
49 struct device *dev;
50 long freq;
51
52 if (smp_processor_id() != cpu)
53 return -ENODEV;
54
55 dev = get_cpu_device(cpu);
56
57 /* Convert target_freq from kHz to Hz */
58 freq = clk_round_rate(cpuclk, target->freq * 1000);
59
60 if (freq < (policy->min * 1000) || freq > (policy->max * 1000))
61 return -EINVAL;
62
63 dev_dbg(dev, "requested frequency %u Hz\n", target->freq * 1000);
64
65 freqs.old = sh_cpufreq_get(cpu);
66 freqs.new = (freq + 500) / 1000;
67 freqs.flags = 0;
68
69 cpufreq_freq_transition_begin(target->policy, &freqs);
70 clk_set_rate(cpuclk, freq);
71 cpufreq_freq_transition_end(target->policy, &freqs, 0);
72
73 dev_dbg(dev, "set frequency %lu Hz\n", freq);
74 return 0;
75}
76
77/*
78 * Here we notify other drivers of the proposed change and the final change.
79 */
80static int sh_cpufreq_target(struct cpufreq_policy *policy,
81 unsigned int target_freq,
82 unsigned int relation)
83{
84 struct cpufreq_target data = { .policy = policy, .freq = target_freq };
85
86 return work_on_cpu(policy->cpu, __sh_cpufreq_target, &data);
87}
88
89static int sh_cpufreq_verify(struct cpufreq_policy_data *policy)
90{
91 struct clk *cpuclk = &per_cpu(sh_cpuclk, policy->cpu);
92
93 if (policy->freq_table)
94 return cpufreq_frequency_table_verify(policy);
95
96 cpufreq_verify_within_cpu_limits(policy);
97
98 policy->min = (clk_round_rate(cpuclk, 1) + 500) / 1000;
99 policy->max = (clk_round_rate(cpuclk, ~0UL) + 500) / 1000;
100
101 cpufreq_verify_within_cpu_limits(policy);
102 return 0;
103}
104
105static int sh_cpufreq_cpu_init(struct cpufreq_policy *policy)
106{
107 unsigned int cpu = policy->cpu;
108 struct clk *cpuclk = &per_cpu(sh_cpuclk, cpu);
109 struct cpufreq_frequency_table *freq_table;
110 struct device *dev;
111
112 dev = get_cpu_device(cpu);
113
114 cpuclk = clk_get(dev, "cpu_clk");
115 if (IS_ERR(cpuclk)) {
116 dev_err(dev, "couldn't get CPU clk\n");
117 return PTR_ERR(cpuclk);
118 }
119
120 freq_table = cpuclk->nr_freqs ? cpuclk->freq_table : NULL;
121 if (freq_table) {
122 policy->freq_table = freq_table;
123 } else {
124 dev_notice(dev, "no frequency table found, falling back "
125 "to rate rounding.\n");
126
127 policy->min = policy->cpuinfo.min_freq =
128 (clk_round_rate(cpuclk, 1) + 500) / 1000;
129 policy->max = policy->cpuinfo.max_freq =
130 (clk_round_rate(cpuclk, ~0UL) + 500) / 1000;
131 }
132
133 return 0;
134}
135
136static void sh_cpufreq_cpu_exit(struct cpufreq_policy *policy)
137{
138 unsigned int cpu = policy->cpu;
139 struct clk *cpuclk = &per_cpu(sh_cpuclk, cpu);
140
141 clk_put(cpuclk);
142}
143
144static struct cpufreq_driver sh_cpufreq_driver = {
145 .name = "sh",
146 .flags = CPUFREQ_NO_AUTO_DYNAMIC_SWITCHING,
147 .get = sh_cpufreq_get,
148 .target = sh_cpufreq_target,
149 .verify = sh_cpufreq_verify,
150 .init = sh_cpufreq_cpu_init,
151 .exit = sh_cpufreq_cpu_exit,
152};
153
154static int __init sh_cpufreq_module_init(void)
155{
156 pr_notice("SuperH CPU frequency driver.\n");
157 return cpufreq_register_driver(&sh_cpufreq_driver);
158}
159
160static void __exit sh_cpufreq_module_exit(void)
161{
162 cpufreq_unregister_driver(&sh_cpufreq_driver);
163}
164
165module_init(sh_cpufreq_module_init);
166module_exit(sh_cpufreq_module_exit);
167
168MODULE_AUTHOR("Paul Mundt <lethal@linux-sh.org>");
169MODULE_DESCRIPTION("cpufreq driver for SuperH");
170MODULE_LICENSE("GPL");