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 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 } 145 146 static 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 }; 156 157 static 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 } 162 163 static void __exit sh_cpufreq_module_exit(void) 164 { 165 cpufreq_unregister_driver(&sh_cpufreq_driver); 166 } 167 168 module_init(sh_cpufreq_module_init); 169 module_exit(sh_cpufreq_module_exit); 170 171 MODULE_AUTHOR("Paul Mundt <lethal@linux-sh.org>"); 172 MODULE_DESCRIPTION("cpufreq driver for SuperH"); 173 MODULE_LICENSE("GPL"); 174