2 * cpufreq driver for the SuperH processors.
4 * Copyright (C) 2002 - 2012 Paul Mundt
5 * Copyright (C) 2002 M. R. Brown
7 * Clock framework bits from arch/avr32/mach-at32ap/cpufreq.c
9 * Copyright (C) 2004-2007 Atmel Corporation
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
15 #define pr_fmt(fmt) "cpufreq: " fmt
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/sched.h> /* set_cpus_allowed() */
27 #include <linux/clk.h>
28 #include <linux/percpu.h>
29 #include <linux/sh_clk.h>
31 static DEFINE_PER_CPU(struct clk, sh_cpuclk);
33 static unsigned int sh_cpufreq_get(unsigned int cpu)
35 return (clk_get_rate(&per_cpu(sh_cpuclk, cpu)) + 500) / 1000;
39 * Here we notify other drivers of the proposed change and the final change.
41 static int sh_cpufreq_target(struct cpufreq_policy *policy,
42 unsigned int target_freq,
43 unsigned int relation)
45 unsigned int cpu = policy->cpu;
46 struct clk *cpuclk = &per_cpu(sh_cpuclk, cpu);
47 cpumask_t cpus_allowed;
48 struct cpufreq_freqs freqs;
52 cpus_allowed = current->cpus_allowed;
53 set_cpus_allowed_ptr(current, cpumask_of(cpu));
55 BUG_ON(smp_processor_id() != cpu);
57 dev = get_cpu_device(cpu);
59 /* Convert target_freq from kHz to Hz */
60 freq = clk_round_rate(cpuclk, target_freq * 1000);
62 if (freq < (policy->min * 1000) || freq > (policy->max * 1000))
65 dev_dbg(dev, "requested frequency %u Hz\n", target_freq * 1000);
67 freqs.old = sh_cpufreq_get(cpu);
68 freqs.new = (freq + 500) / 1000;
71 cpufreq_freq_transition_begin(policy, &freqs);
72 set_cpus_allowed_ptr(current, &cpus_allowed);
73 clk_set_rate(cpuclk, freq);
74 cpufreq_freq_transition_end(policy, &freqs, 0);
76 dev_dbg(dev, "set frequency %lu Hz\n", freq);
81 static int sh_cpufreq_verify(struct cpufreq_policy *policy)
83 struct clk *cpuclk = &per_cpu(sh_cpuclk, policy->cpu);
84 struct cpufreq_frequency_table *freq_table;
86 freq_table = cpuclk->nr_freqs ? cpuclk->freq_table : NULL;
88 return cpufreq_frequency_table_verify(policy, freq_table);
90 cpufreq_verify_within_cpu_limits(policy);
92 policy->min = (clk_round_rate(cpuclk, 1) + 500) / 1000;
93 policy->max = (clk_round_rate(cpuclk, ~0UL) + 500) / 1000;
95 cpufreq_verify_within_cpu_limits(policy);
99 static int sh_cpufreq_cpu_init(struct cpufreq_policy *policy)
101 unsigned int cpu = policy->cpu;
102 struct clk *cpuclk = &per_cpu(sh_cpuclk, cpu);
103 struct cpufreq_frequency_table *freq_table;
106 dev = get_cpu_device(cpu);
108 cpuclk = clk_get(dev, "cpu_clk");
109 if (IS_ERR(cpuclk)) {
110 dev_err(dev, "couldn't get CPU clk\n");
111 return PTR_ERR(cpuclk);
114 freq_table = cpuclk->nr_freqs ? cpuclk->freq_table : NULL;
118 result = cpufreq_table_validate_and_show(policy, freq_table);
122 dev_notice(dev, "no frequency table found, falling back "
123 "to rate rounding.\n");
125 policy->min = policy->cpuinfo.min_freq =
126 (clk_round_rate(cpuclk, 1) + 500) / 1000;
127 policy->max = policy->cpuinfo.max_freq =
128 (clk_round_rate(cpuclk, ~0UL) + 500) / 1000;
131 policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
133 dev_info(dev, "CPU Frequencies - Minimum %u.%03u MHz, "
134 "Maximum %u.%03u MHz.\n",
135 policy->min / 1000, policy->min % 1000,
136 policy->max / 1000, policy->max % 1000);
141 static int sh_cpufreq_cpu_exit(struct cpufreq_policy *policy)
143 unsigned int cpu = policy->cpu;
144 struct clk *cpuclk = &per_cpu(sh_cpuclk, cpu);
151 static struct cpufreq_driver sh_cpufreq_driver = {
153 .get = sh_cpufreq_get,
154 .target = sh_cpufreq_target,
155 .verify = sh_cpufreq_verify,
156 .init = sh_cpufreq_cpu_init,
157 .exit = sh_cpufreq_cpu_exit,
158 .attr = cpufreq_generic_attr,
161 static int __init sh_cpufreq_module_init(void)
163 pr_notice("SuperH CPU frequency driver.\n");
164 return cpufreq_register_driver(&sh_cpufreq_driver);
167 static void __exit sh_cpufreq_module_exit(void)
169 cpufreq_unregister_driver(&sh_cpufreq_driver);
172 module_init(sh_cpufreq_module_init);
173 module_exit(sh_cpufreq_module_exit);
175 MODULE_AUTHOR("Paul Mundt <lethal@linux-sh.org>");
176 MODULE_DESCRIPTION("cpufreq driver for SuperH");
177 MODULE_LICENSE("GPL");