88c8feedf785d45eb80fb7a522e2cfd2048cae49
[linux-3.10.git] / arch / sh / kernel / cpufreq.c
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
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  */
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         cpus_allowed = current->cpus_allowed;
55         set_cpus_allowed_ptr(current, cpumask_of(cpu));
56
57         BUG_ON(smp_processor_id() != cpu);
58
59         dev = get_cpu_device(cpu);
60
61         /* Convert target_freq from kHz to Hz */
62         freq = clk_round_rate(cpuclk, target_freq * 1000);
63
64         if (freq < (policy->min * 1000) || freq > (policy->max * 1000))
65                 return -EINVAL;
66
67         dev_dbg(dev, "requested frequency %u Hz\n", target_freq * 1000);
68
69         freqs.old       = sh_cpufreq_get(cpu);
70         freqs.new       = (freq + 500) / 1000;
71         freqs.flags     = 0;
72
73         cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);
74         set_cpus_allowed_ptr(current, &cpus_allowed);
75         clk_set_rate(cpuclk, freq);
76         cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);
77
78         dev_dbg(dev, "set frequency %lu Hz\n", freq);
79
80         return 0;
81 }
82
83 static int sh_cpufreq_verify(struct cpufreq_policy *policy)
84 {
85         struct clk *cpuclk = &per_cpu(sh_cpuclk, policy->cpu);
86         struct cpufreq_frequency_table *freq_table;
87
88         freq_table = cpuclk->nr_freqs ? cpuclk->freq_table : NULL;
89         if (freq_table)
90                 return cpufreq_frequency_table_verify(policy, freq_table);
91
92         cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq,
93                                      policy->cpuinfo.max_freq);
94
95         policy->min = (clk_round_rate(cpuclk, 1) + 500) / 1000;
96         policy->max = (clk_round_rate(cpuclk, ~0UL) + 500) / 1000;
97
98         cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq,
99                                      policy->cpuinfo.max_freq);
100
101         return 0;
102 }
103
104 static int sh_cpufreq_cpu_init(struct cpufreq_policy *policy)
105 {
106         unsigned int cpu = policy->cpu;
107         struct clk *cpuclk = &per_cpu(sh_cpuclk, cpu);
108         struct cpufreq_frequency_table *freq_table;
109         struct device *dev;
110
111         dev = get_cpu_device(cpu);
112
113         cpuclk = clk_get(dev, "cpu_clk");
114         if (IS_ERR(cpuclk)) {
115                 dev_err(dev, "couldn't get CPU clk\n");
116                 return PTR_ERR(cpuclk);
117         }
118
119         policy->cur = sh_cpufreq_get(cpu);
120
121         freq_table = cpuclk->nr_freqs ? cpuclk->freq_table : NULL;
122         if (freq_table) {
123                 int result;
124
125                 result = cpufreq_frequency_table_cpuinfo(policy, freq_table);
126                 if (!result)
127                         cpufreq_frequency_table_get_attr(freq_table, cpu);
128         } else {
129                 dev_notice(dev, "no frequency table found, falling back "
130                            "to rate rounding.\n");
131
132                 policy->min = policy->cpuinfo.min_freq =
133                         (clk_round_rate(cpuclk, 1) + 500) / 1000;
134                 policy->max = policy->cpuinfo.max_freq =
135                         (clk_round_rate(cpuclk, ~0UL) + 500) / 1000;
136         }
137
138         policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
139
140         dev_info(dev, "CPU Frequencies - Minimum %u.%03u MHz, "
141                "Maximum %u.%03u MHz.\n",
142                policy->min / 1000, policy->min % 1000,
143                policy->max / 1000, policy->max % 1000);
144
145         return 0;
146 }
147
148 static int sh_cpufreq_cpu_exit(struct cpufreq_policy *policy)
149 {
150         unsigned int cpu = policy->cpu;
151         struct clk *cpuclk = &per_cpu(sh_cpuclk, cpu);
152
153         cpufreq_frequency_table_put_attr(cpu);
154         clk_put(cpuclk);
155
156         return 0;
157 }
158
159 static struct freq_attr *sh_freq_attr[] = {
160         &cpufreq_freq_attr_scaling_available_freqs,
161         NULL,
162 };
163
164 static struct cpufreq_driver sh_cpufreq_driver = {
165         .owner          = THIS_MODULE,
166         .name           = "sh",
167         .get            = sh_cpufreq_get,
168         .target         = sh_cpufreq_target,
169         .verify         = sh_cpufreq_verify,
170         .init           = sh_cpufreq_cpu_init,
171         .exit           = sh_cpufreq_cpu_exit,
172         .attr           = sh_freq_attr,
173 };
174
175 static int __init sh_cpufreq_module_init(void)
176 {
177         pr_notice("SuperH CPU frequency driver.\n");
178         return cpufreq_register_driver(&sh_cpufreq_driver);
179 }
180
181 static void __exit sh_cpufreq_module_exit(void)
182 {
183         cpufreq_unregister_driver(&sh_cpufreq_driver);
184 }
185
186 module_init(sh_cpufreq_module_init);
187 module_exit(sh_cpufreq_module_exit);
188
189 MODULE_AUTHOR("Paul Mundt <lethal@linux-sh.org>");
190 MODULE_DESCRIPTION("cpufreq driver for SuperH");
191 MODULE_LICENSE("GPL");