GNU Linux-libre 5.19-rc6-gnu
[releases.git] / drivers / cpufreq / sh-cpufreq.c
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
30 static DEFINE_PER_CPU(struct clk, sh_cpuclk);
31
32 struct cpufreq_target {
33         struct cpufreq_policy   *policy;
34         unsigned int            freq;
35 };
36
37 static unsigned int sh_cpufreq_get(unsigned int cpu)
38 {
39         return (clk_get_rate(&per_cpu(sh_cpuclk, cpu)) + 500) / 1000;
40 }
41
42 static 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  */
80 static 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
89 static int sh_cpufreq_verify(struct cpufreq_policy_data *policy)
90 {
91         struct clk *cpuclk = &per_cpu(sh_cpuclk, policy->cpu);
92         struct cpufreq_frequency_table *freq_table;
93
94         freq_table = cpuclk->nr_freqs ? cpuclk->freq_table : NULL;
95         if (freq_table)
96                 return cpufreq_frequency_table_verify(policy, freq_table);
97
98         cpufreq_verify_within_cpu_limits(policy);
99
100         policy->min = (clk_round_rate(cpuclk, 1) + 500) / 1000;
101         policy->max = (clk_round_rate(cpuclk, ~0UL) + 500) / 1000;
102
103         cpufreq_verify_within_cpu_limits(policy);
104         return 0;
105 }
106
107 static int sh_cpufreq_cpu_init(struct cpufreq_policy *policy)
108 {
109         unsigned int cpu = policy->cpu;
110         struct clk *cpuclk = &per_cpu(sh_cpuclk, cpu);
111         struct cpufreq_frequency_table *freq_table;
112         struct device *dev;
113
114         dev = get_cpu_device(cpu);
115
116         cpuclk = clk_get(dev, "cpu_clk");
117         if (IS_ERR(cpuclk)) {
118                 dev_err(dev, "couldn't get CPU clk\n");
119                 return PTR_ERR(cpuclk);
120         }
121
122         freq_table = cpuclk->nr_freqs ? cpuclk->freq_table : NULL;
123         if (freq_table) {
124                 policy->freq_table = freq_table;
125         } else {
126                 dev_notice(dev, "no frequency table found, falling back "
127                            "to rate rounding.\n");
128
129                 policy->min = policy->cpuinfo.min_freq =
130                         (clk_round_rate(cpuclk, 1) + 500) / 1000;
131                 policy->max = policy->cpuinfo.max_freq =
132                         (clk_round_rate(cpuclk, ~0UL) + 500) / 1000;
133         }
134
135         return 0;
136 }
137
138 static int sh_cpufreq_cpu_exit(struct cpufreq_policy *policy)
139 {
140         unsigned int cpu = policy->cpu;
141         struct clk *cpuclk = &per_cpu(sh_cpuclk, cpu);
142
143         clk_put(cpuclk);
144
145         return 0;
146 }
147
148 static struct cpufreq_driver sh_cpufreq_driver = {
149         .name           = "sh",
150         .flags          = CPUFREQ_NO_AUTO_DYNAMIC_SWITCHING,
151         .get            = sh_cpufreq_get,
152         .target         = sh_cpufreq_target,
153         .verify         = sh_cpufreq_verify,
154         .init           = sh_cpufreq_cpu_init,
155         .exit           = sh_cpufreq_cpu_exit,
156         .attr           = cpufreq_generic_attr,
157 };
158
159 static int __init sh_cpufreq_module_init(void)
160 {
161         pr_notice("SuperH CPU frequency driver.\n");
162         return cpufreq_register_driver(&sh_cpufreq_driver);
163 }
164
165 static void __exit sh_cpufreq_module_exit(void)
166 {
167         cpufreq_unregister_driver(&sh_cpufreq_driver);
168 }
169
170 module_init(sh_cpufreq_module_init);
171 module_exit(sh_cpufreq_module_exit);
172
173 MODULE_AUTHOR("Paul Mundt <lethal@linux-sh.org>");
174 MODULE_DESCRIPTION("cpufreq driver for SuperH");
175 MODULE_LICENSE("GPL");