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 static unsigned int sh_cpufreq_get(unsigned int cpu) 34 { 35 return (clk_get_rate(&per_cpu(sh_cpuclk, cpu)) + 500) / 1000; 36 } 37 38 /* 39 * Here we notify other drivers of the proposed change and the final change. 40 */ 41 static int sh_cpufreq_target(struct cpufreq_policy *policy, 42 unsigned int target_freq, 43 unsigned int relation) 44 { 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; 49 struct device *dev; 50 long freq; 51 52 cpus_allowed = current->cpus_allowed; 53 set_cpus_allowed_ptr(current, cpumask_of(cpu)); 54 55 BUG_ON(smp_processor_id() != cpu); 56 57 dev = get_cpu_device(cpu); 58 59 /* Convert target_freq from kHz to Hz */ 60 freq = clk_round_rate(cpuclk, target_freq * 1000); 61 62 if (freq < (policy->min * 1000) || freq > (policy->max * 1000)) 63 return -EINVAL; 64 65 dev_dbg(dev, "requested frequency %u Hz\n", target_freq * 1000); 66 67 freqs.old = sh_cpufreq_get(cpu); 68 freqs.new = (freq + 500) / 1000; 69 freqs.flags = 0; 70 71 cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE); 72 set_cpus_allowed_ptr(current, &cpus_allowed); 73 clk_set_rate(cpuclk, freq); 74 cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE); 75 76 dev_dbg(dev, "set frequency %lu Hz\n", freq); 77 78 return 0; 79 } 80 81 static int sh_cpufreq_verify(struct cpufreq_policy *policy) 82 { 83 struct clk *cpuclk = &per_cpu(sh_cpuclk, policy->cpu); 84 struct cpufreq_frequency_table *freq_table; 85 86 freq_table = cpuclk->nr_freqs ? cpuclk->freq_table : NULL; 87 if (freq_table) 88 return cpufreq_frequency_table_verify(policy, freq_table); 89 90 cpufreq_verify_within_cpu_limits(policy); 91 92 policy->min = (clk_round_rate(cpuclk, 1) + 500) / 1000; 93 policy->max = (clk_round_rate(cpuclk, ~0UL) + 500) / 1000; 94 95 cpufreq_verify_within_cpu_limits(policy); 96 return 0; 97 } 98 99 static int sh_cpufreq_cpu_init(struct cpufreq_policy *policy) 100 { 101 unsigned int cpu = policy->cpu; 102 struct clk *cpuclk = &per_cpu(sh_cpuclk, cpu); 103 struct cpufreq_frequency_table *freq_table; 104 struct device *dev; 105 106 dev = get_cpu_device(cpu); 107 108 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); 112 } 113 114 freq_table = cpuclk->nr_freqs ? cpuclk->freq_table : NULL; 115 if (freq_table) { 116 int result; 117 118 result = cpufreq_table_validate_and_show(policy, freq_table); 119 if (result) 120 return result; 121 } else { 122 dev_notice(dev, "no frequency table found, falling back " 123 "to rate rounding.\n"); 124 125 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; 129 } 130 131 policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL; 132 133 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); 137 138 return 0; 139 } 140 141 static int sh_cpufreq_cpu_exit(struct cpufreq_policy *policy) 142 { 143 unsigned int cpu = policy->cpu; 144 struct clk *cpuclk = &per_cpu(sh_cpuclk, cpu); 145 146 cpufreq_frequency_table_put_attr(cpu); 147 clk_put(cpuclk); 148 149 return 0; 150 } 151 152 static struct cpufreq_driver sh_cpufreq_driver = { 153 .name = "sh", 154 .get = sh_cpufreq_get, 155 .target = sh_cpufreq_target, 156 .verify = sh_cpufreq_verify, 157 .init = sh_cpufreq_cpu_init, 158 .exit = sh_cpufreq_cpu_exit, 159 .attr = cpufreq_generic_attr, 160 }; 161 162 static int __init sh_cpufreq_module_init(void) 163 { 164 pr_notice("SuperH CPU frequency driver.\n"); 165 return cpufreq_register_driver(&sh_cpufreq_driver); 166 } 167 168 static void __exit sh_cpufreq_module_exit(void) 169 { 170 cpufreq_unregister_driver(&sh_cpufreq_driver); 171 } 172 173 module_init(sh_cpufreq_module_init); 174 module_exit(sh_cpufreq_module_exit); 175 176 MODULE_AUTHOR("Paul Mundt <lethal@linux-sh.org>"); 177 MODULE_DESCRIPTION("cpufreq driver for SuperH"); 178 MODULE_LICENSE("GPL"); 179