1/* 2 * arch/sh/kernel/cpufreq.c 3 * 4 * cpufreq driver for the SuperH processors. 5 * 6 * Copyright (C) 2002 - 2007 Paul Mundt 7 * Copyright (C) 2002 M. R. Brown 8 * 9 * Clock framework bits from arch/avr32/mach-at32ap/cpufreq.c 10 * 11 * Copyright (C) 2004-2007 Atmel Corporation 12 * 13 * This file is subject to the terms and conditions of the GNU General Public 14 * License. See the file "COPYING" in the main directory of this archive 15 * for more details. 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/smp.h> 25#include <linux/sched.h> /* set_cpus_allowed() */ 26#include <linux/clk.h> 27 28static struct clk *cpuclk; 29 30static unsigned int sh_cpufreq_get(unsigned int cpu) 31{ 32 return (clk_get_rate(cpuclk) + 500) / 1000; 33} 34 35/* 36 * Here we notify other drivers of the proposed change and the final change. 37 */ 38static int sh_cpufreq_target(struct cpufreq_policy *policy, 39 unsigned int target_freq, 40 unsigned int relation) 41{ 42 unsigned int cpu = policy->cpu; 43 cpumask_t cpus_allowed; 44 struct cpufreq_freqs freqs; 45 long freq; 46 47 if (!cpu_online(cpu)) 48 return -ENODEV; 49 50 cpus_allowed = current->cpus_allowed; 51 set_cpus_allowed_ptr(current, cpumask_of(cpu)); 52 53 BUG_ON(smp_processor_id() != cpu); 54 55 /* Convert target_freq from kHz to Hz */ 56 freq = clk_round_rate(cpuclk, target_freq * 1000); 57 58 if (freq < (policy->min * 1000) || freq > (policy->max * 1000)) 59 return -EINVAL; 60 61 pr_debug("cpufreq: requested frequency %u Hz\n", target_freq * 1000); 62 63 freqs.cpu = cpu; 64 freqs.old = sh_cpufreq_get(cpu); 65 freqs.new = (freq + 500) / 1000; 66 freqs.flags = 0; 67 68 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE); 69 set_cpus_allowed_ptr(current, &cpus_allowed); 70 clk_set_rate(cpuclk, freq); 71 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE); 72 73 pr_debug("cpufreq: set frequency %lu Hz\n", freq); 74 75 return 0; 76} 77 78static int sh_cpufreq_cpu_init(struct cpufreq_policy *policy) 79{ 80 if (!cpu_online(policy->cpu)) 81 return -ENODEV; 82 83 cpuclk = clk_get(NULL, "cpu_clk"); 84 if (IS_ERR(cpuclk)) { 85 printk(KERN_ERR "cpufreq: couldn't get CPU#%d clk\n", 86 policy->cpu); 87 return PTR_ERR(cpuclk); 88 } 89 90 /* cpuinfo and default policy values */ 91 policy->cpuinfo.min_freq = (clk_round_rate(cpuclk, 1) + 500) / 1000; 92 policy->cpuinfo.max_freq = (clk_round_rate(cpuclk, ~0UL) + 500) / 1000; 93 policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL; 94 95 policy->cur = sh_cpufreq_get(policy->cpu); 96 policy->min = policy->cpuinfo.min_freq; 97 policy->max = policy->cpuinfo.max_freq; 98 99 /* 100 * Catch the cases where the clock framework hasn't been wired up 101 * properly to support scaling. 102 */ 103 if (unlikely(policy->min == policy->max)) { 104 printk(KERN_ERR "cpufreq: clock framework rate rounding " 105 "not supported on CPU#%d.\n", policy->cpu); 106 107 clk_put(cpuclk); 108 return -EINVAL; 109 } 110 111 printk(KERN_INFO "cpufreq: CPU#%d Frequencies - Minimum %u.%03u MHz, " 112 "Maximum %u.%03u MHz.\n", 113 policy->cpu, policy->min / 1000, policy->min % 1000, 114 policy->max / 1000, policy->max % 1000); 115 116 return 0; 117} 118 119static int sh_cpufreq_verify(struct cpufreq_policy *policy) 120{ 121 cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq, 122 policy->cpuinfo.max_freq); 123 return 0; 124} 125 126static int sh_cpufreq_exit(struct cpufreq_policy *policy) 127{ 128 clk_put(cpuclk); 129 return 0; 130} 131 132static struct cpufreq_driver sh_cpufreq_driver = { 133 .owner = THIS_MODULE, 134 .name = "sh", 135 .init = sh_cpufreq_cpu_init, 136 .verify = sh_cpufreq_verify, 137 .target = sh_cpufreq_target, 138 .get = sh_cpufreq_get, 139 .exit = sh_cpufreq_exit, 140}; 141 142static int __init sh_cpufreq_module_init(void) 143{ 144 printk(KERN_INFO "cpufreq: SuperH CPU frequency driver.\n"); 145 return cpufreq_register_driver(&sh_cpufreq_driver); 146} 147 148static void __exit sh_cpufreq_module_exit(void) 149{ 150 cpufreq_unregister_driver(&sh_cpufreq_driver); 151} 152 153module_init(sh_cpufreq_module_init); 154module_exit(sh_cpufreq_module_exit); 155 156MODULE_AUTHOR("Paul Mundt <lethal@linux-sh.org>"); 157MODULE_DESCRIPTION("cpufreq driver for SuperH"); 158MODULE_LICENSE("GPL"); 159