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1/*2 * cpufreq driver for the SuperH processors.3 *4 * Copyright (C) 2002 - 2012 Paul Mundt5 * Copyright (C) 2002 M. R. Brown6 *7 * Clock framework bits from arch/avr32/mach-at32ap/cpufreq.c8 *9 * Copyright (C) 2004-2007 Atmel Corporation10 *11 * This file is subject to the terms and conditions of the GNU General Public12 * License. See the file "COPYING" in the main directory of this archive13 * for more details.14 */15#define pr_fmt(fmt) "cpufreq: " fmt16 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 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 107static 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 138static void 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 146static struct cpufreq_driver sh_cpufreq_driver = {147 .name = "sh",148 .flags = CPUFREQ_NO_AUTO_DYNAMIC_SWITCHING,149 .get = sh_cpufreq_get,150 .target = sh_cpufreq_target,151 .verify = sh_cpufreq_verify,152 .init = sh_cpufreq_cpu_init,153 .exit = sh_cpufreq_cpu_exit,154 .attr = cpufreq_generic_attr,155};156 157static int __init sh_cpufreq_module_init(void)158{159 pr_notice("SuperH CPU frequency driver.\n");160 return cpufreq_register_driver(&sh_cpufreq_driver);161}162 163static void __exit sh_cpufreq_module_exit(void)164{165 cpufreq_unregister_driver(&sh_cpufreq_driver);166}167 168module_init(sh_cpufreq_module_init);169module_exit(sh_cpufreq_module_exit);170 171MODULE_AUTHOR("Paul Mundt <lethal@linux-sh.org>");172MODULE_DESCRIPTION("cpufreq driver for SuperH");173MODULE_LICENSE("GPL");174