1 /*
2 * arch/sh/kernel/cpufreq.c
3 *
4 * cpufreq driver for the SuperH processors.
5 *
6 * Copyright (C) 2002 - 2012 Paul Mundt
7 * Copyright (C) 2002 M. R. Brown
8 *
9 * Clock framework bits from arch/avr32/mach-at32ap/cpufreq.c
10 *
11 * Copyright (C) 2004-2007 Atmel Corporation
12 *
13 * This file is subject to the terms and conditions of the GNU General Public
14 * License. See the file "COPYING" in the main directory of this archive
15 * for more details.
16 */
17 #define pr_fmt(fmt) "cpufreq: " fmt
18
19 #include <linux/types.h>
20 #include <linux/cpufreq.h>
21 #include <linux/kernel.h>
22 #include <linux/module.h>
23 #include <linux/init.h>
24 #include <linux/err.h>
25 #include <linux/cpumask.h>
26 #include <linux/cpu.h>
27 #include <linux/smp.h>
28 #include <linux/sched.h> /* set_cpus_allowed() */
29 #include <linux/clk.h>
30 #include <linux/percpu.h>
31 #include <linux/sh_clk.h>
32
33 static DEFINE_PER_CPU(struct clk, sh_cpuclk);
34
sh_cpufreq_get(unsigned int cpu)35 static unsigned int sh_cpufreq_get(unsigned int cpu)
36 {
37 return (clk_get_rate(&per_cpu(sh_cpuclk, cpu)) + 500) / 1000;
38 }
39
40 /*
41 * Here we notify other drivers of the proposed change and the final change.
42 */
sh_cpufreq_target(struct cpufreq_policy * policy,unsigned int target_freq,unsigned int relation)43 static int sh_cpufreq_target(struct cpufreq_policy *policy,
44 unsigned int target_freq,
45 unsigned int relation)
46 {
47 unsigned int cpu = policy->cpu;
48 struct clk *cpuclk = &per_cpu(sh_cpuclk, cpu);
49 cpumask_t cpus_allowed;
50 struct cpufreq_freqs freqs;
51 struct device *dev;
52 long freq;
53
54 if (!cpu_online(cpu))
55 return -ENODEV;
56
57 cpus_allowed = current->cpus_allowed;
58 set_cpus_allowed_ptr(current, cpumask_of(cpu));
59
60 BUG_ON(smp_processor_id() != cpu);
61
62 dev = get_cpu_device(cpu);
63
64 /* Convert target_freq from kHz to Hz */
65 freq = clk_round_rate(cpuclk, target_freq * 1000);
66
67 if (freq < (policy->min * 1000) || freq > (policy->max * 1000))
68 return -EINVAL;
69
70 dev_dbg(dev, "requested frequency %u Hz\n", target_freq * 1000);
71
72 freqs.cpu = cpu;
73 freqs.old = sh_cpufreq_get(cpu);
74 freqs.new = (freq + 500) / 1000;
75 freqs.flags = 0;
76
77 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
78 set_cpus_allowed_ptr(current, &cpus_allowed);
79 clk_set_rate(cpuclk, freq);
80 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
81
82 dev_dbg(dev, "set frequency %lu Hz\n", freq);
83
84 return 0;
85 }
86
sh_cpufreq_verify(struct cpufreq_policy * policy)87 static int sh_cpufreq_verify(struct cpufreq_policy *policy)
88 {
89 struct clk *cpuclk = &per_cpu(sh_cpuclk, policy->cpu);
90 struct cpufreq_frequency_table *freq_table;
91
92 freq_table = cpuclk->nr_freqs ? cpuclk->freq_table : NULL;
93 if (freq_table)
94 return cpufreq_frequency_table_verify(policy, freq_table);
95
96 cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq,
97 policy->cpuinfo.max_freq);
98
99 policy->min = (clk_round_rate(cpuclk, 1) + 500) / 1000;
100 policy->max = (clk_round_rate(cpuclk, ~0UL) + 500) / 1000;
101
102 cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq,
103 policy->cpuinfo.max_freq);
104
105 return 0;
106 }
107
sh_cpufreq_cpu_init(struct cpufreq_policy * policy)108 static int sh_cpufreq_cpu_init(struct cpufreq_policy *policy)
109 {
110 unsigned int cpu = policy->cpu;
111 struct clk *cpuclk = &per_cpu(sh_cpuclk, cpu);
112 struct cpufreq_frequency_table *freq_table;
113 struct device *dev;
114
115 if (!cpu_online(cpu))
116 return -ENODEV;
117
118 dev = get_cpu_device(cpu);
119
120 cpuclk = clk_get(dev, "cpu_clk");
121 if (IS_ERR(cpuclk)) {
122 dev_err(dev, "couldn't get CPU clk\n");
123 return PTR_ERR(cpuclk);
124 }
125
126 policy->cur = policy->min = policy->max = sh_cpufreq_get(cpu);
127
128 freq_table = cpuclk->nr_freqs ? cpuclk->freq_table : NULL;
129 if (freq_table) {
130 int result;
131
132 result = cpufreq_frequency_table_cpuinfo(policy, freq_table);
133 if (!result)
134 cpufreq_frequency_table_get_attr(freq_table, cpu);
135 } else {
136 dev_notice(dev, "no frequency table found, falling back "
137 "to rate rounding.\n");
138
139 policy->cpuinfo.min_freq =
140 (clk_round_rate(cpuclk, 1) + 500) / 1000;
141 policy->cpuinfo.max_freq =
142 (clk_round_rate(cpuclk, ~0UL) + 500) / 1000;
143 }
144
145 policy->min = policy->cpuinfo.min_freq;
146 policy->max = policy->cpuinfo.max_freq;
147
148 policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
149
150 dev_info(dev, "CPU Frequencies - Minimum %u.%03u MHz, "
151 "Maximum %u.%03u MHz.\n",
152 policy->min / 1000, policy->min % 1000,
153 policy->max / 1000, policy->max % 1000);
154
155 return 0;
156 }
157
sh_cpufreq_cpu_exit(struct cpufreq_policy * policy)158 static int sh_cpufreq_cpu_exit(struct cpufreq_policy *policy)
159 {
160 unsigned int cpu = policy->cpu;
161 struct clk *cpuclk = &per_cpu(sh_cpuclk, cpu);
162
163 cpufreq_frequency_table_put_attr(cpu);
164 clk_put(cpuclk);
165
166 return 0;
167 }
168
169 static struct freq_attr *sh_freq_attr[] = {
170 &cpufreq_freq_attr_scaling_available_freqs,
171 NULL,
172 };
173
174 static struct cpufreq_driver sh_cpufreq_driver = {
175 .owner = THIS_MODULE,
176 .name = "sh",
177 .get = sh_cpufreq_get,
178 .target = sh_cpufreq_target,
179 .verify = sh_cpufreq_verify,
180 .init = sh_cpufreq_cpu_init,
181 .exit = sh_cpufreq_cpu_exit,
182 .attr = sh_freq_attr,
183 };
184
sh_cpufreq_module_init(void)185 static int __init sh_cpufreq_module_init(void)
186 {
187 pr_notice("SuperH CPU frequency driver.\n");
188 return cpufreq_register_driver(&sh_cpufreq_driver);
189 }
190
sh_cpufreq_module_exit(void)191 static void __exit sh_cpufreq_module_exit(void)
192 {
193 cpufreq_unregister_driver(&sh_cpufreq_driver);
194 }
195
196 module_init(sh_cpufreq_module_init);
197 module_exit(sh_cpufreq_module_exit);
198
199 MODULE_AUTHOR("Paul Mundt <lethal@linux-sh.org>");
200 MODULE_DESCRIPTION("cpufreq driver for SuperH");
201 MODULE_LICENSE("GPL");
202