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/sched.h> /* set_cpus_allowed() */ 27 #include <linux/clk.h> 28 #include <linux/percpu.h> 29 #include <linux/sh_clk.h> 30 31 static DEFINE_PER_CPU(struct clk, sh_cpuclk); 32 33 struct cpufreq_target { 34 struct cpufreq_policy *policy; 35 unsigned int freq; 36 }; 37 38 static unsigned int sh_cpufreq_get(unsigned int cpu) 39 { 40 return (clk_get_rate(&per_cpu(sh_cpuclk, cpu)) + 500) / 1000; 41 } 42 43 static long __sh_cpufreq_target(void *arg) 44 { 45 struct cpufreq_target *target = arg; 46 struct cpufreq_policy *policy = target->policy; 47 int cpu = policy->cpu; 48 struct clk *cpuclk = &per_cpu(sh_cpuclk, cpu); 49 struct cpufreq_freqs freqs; 50 struct device *dev; 51 long freq; 52 53 if (smp_processor_id() != cpu) 54 return -ENODEV; 55 56 dev = get_cpu_device(cpu); 57 58 /* Convert target_freq from kHz to Hz */ 59 freq = clk_round_rate(cpuclk, target->freq * 1000); 60 61 if (freq < (policy->min * 1000) || freq > (policy->max * 1000)) 62 return -EINVAL; 63 64 dev_dbg(dev, "requested frequency %u Hz\n", target->freq * 1000); 65 66 freqs.old = sh_cpufreq_get(cpu); 67 freqs.new = (freq + 500) / 1000; 68 freqs.flags = 0; 69 70 cpufreq_freq_transition_begin(target->policy, &freqs); 71 clk_set_rate(cpuclk, freq); 72 cpufreq_freq_transition_end(target->policy, &freqs, 0); 73 74 dev_dbg(dev, "set frequency %lu Hz\n", freq); 75 return 0; 76 } 77 78 /* 79 * Here we notify other drivers of the proposed change and the final change. 80 */ 81 static int sh_cpufreq_target(struct cpufreq_policy *policy, 82 unsigned int target_freq, 83 unsigned int relation) 84 { 85 struct cpufreq_target data = { .policy = policy, .freq = target_freq }; 86 87 return work_on_cpu(policy->cpu, __sh_cpufreq_target, &data); 88 } 89 90 static int sh_cpufreq_verify(struct cpufreq_policy *policy) 91 { 92 struct clk *cpuclk = &per_cpu(sh_cpuclk, policy->cpu); 93 struct cpufreq_frequency_table *freq_table; 94 95 freq_table = cpuclk->nr_freqs ? cpuclk->freq_table : NULL; 96 if (freq_table) 97 return cpufreq_frequency_table_verify(policy, freq_table); 98 99 cpufreq_verify_within_cpu_limits(policy); 100 101 policy->min = (clk_round_rate(cpuclk, 1) + 500) / 1000; 102 policy->max = (clk_round_rate(cpuclk, ~0UL) + 500) / 1000; 103 104 cpufreq_verify_within_cpu_limits(policy); 105 return 0; 106 } 107 108 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 dev = get_cpu_device(cpu); 116 117 cpuclk = clk_get(dev, "cpu_clk"); 118 if (IS_ERR(cpuclk)) { 119 dev_err(dev, "couldn't get CPU clk\n"); 120 return PTR_ERR(cpuclk); 121 } 122 123 freq_table = cpuclk->nr_freqs ? cpuclk->freq_table : NULL; 124 if (freq_table) { 125 policy->freq_table = freq_table; 126 } else { 127 dev_notice(dev, "no frequency table found, falling back " 128 "to rate rounding.\n"); 129 130 policy->min = policy->cpuinfo.min_freq = 131 (clk_round_rate(cpuclk, 1) + 500) / 1000; 132 policy->max = policy->cpuinfo.max_freq = 133 (clk_round_rate(cpuclk, ~0UL) + 500) / 1000; 134 } 135 136 return 0; 137 } 138 139 static int sh_cpufreq_cpu_exit(struct cpufreq_policy *policy) 140 { 141 unsigned int cpu = policy->cpu; 142 struct clk *cpuclk = &per_cpu(sh_cpuclk, cpu); 143 144 clk_put(cpuclk); 145 146 return 0; 147 } 148 149 static void sh_cpufreq_cpu_ready(struct cpufreq_policy *policy) 150 { 151 struct device *dev = get_cpu_device(policy->cpu); 152 153 dev_info(dev, "CPU Frequencies - Minimum %u.%03u MHz, " 154 "Maximum %u.%03u MHz.\n", 155 policy->min / 1000, policy->min % 1000, 156 policy->max / 1000, policy->max % 1000); 157 } 158 159 static struct cpufreq_driver sh_cpufreq_driver = { 160 .name = "sh", 161 .flags = CPUFREQ_NO_AUTO_DYNAMIC_SWITCHING, 162 .get = sh_cpufreq_get, 163 .target = sh_cpufreq_target, 164 .verify = sh_cpufreq_verify, 165 .init = sh_cpufreq_cpu_init, 166 .exit = sh_cpufreq_cpu_exit, 167 .ready = sh_cpufreq_cpu_ready, 168 .attr = cpufreq_generic_attr, 169 }; 170 171 static int __init sh_cpufreq_module_init(void) 172 { 173 pr_notice("SuperH CPU frequency driver.\n"); 174 return cpufreq_register_driver(&sh_cpufreq_driver); 175 } 176 177 static void __exit sh_cpufreq_module_exit(void) 178 { 179 cpufreq_unregister_driver(&sh_cpufreq_driver); 180 } 181 182 module_init(sh_cpufreq_module_init); 183 module_exit(sh_cpufreq_module_exit); 184 185 MODULE_AUTHOR("Paul Mundt <lethal@linux-sh.org>"); 186 MODULE_DESCRIPTION("cpufreq driver for SuperH"); 187 MODULE_LICENSE("GPL"); 188