1/* 2 * linux/arch/arm/plat-omap/cpu-omap.c 3 * 4 * CPU frequency scaling for OMAP 5 * 6 * Copyright (C) 2005 Nokia Corporation 7 * Written by Tony Lindgren <tony@atomide.com> 8 * 9 * Based on cpu-sa1110.c, Copyright (C) 2001 Russell King 10 * 11 * This program is free software; you can redistribute it and/or modify 12 * it under the terms of the GNU General Public License version 2 as 13 * published by the Free Software Foundation. 14 */ 15#include <linux/types.h> 16#include <linux/kernel.h> 17#include <linux/sched.h> 18#include <linux/cpufreq.h> 19#include <linux/delay.h> 20#include <linux/init.h> 21#include <linux/err.h> 22#include <linux/clk.h> 23#include <linux/io.h> 24 25#include <mach/hardware.h> 26#include <plat/clock.h> 27#include <asm/system.h> 28 29#define VERY_HI_RATE 900000000 30 31static struct cpufreq_frequency_table *freq_table; 32 33#ifdef CONFIG_ARCH_OMAP1 34#define MPU_CLK "mpu" 35#else 36#define MPU_CLK "virt_prcm_set" 37#endif 38 39static struct clk *mpu_clk; 40 41/* TODO: Add support for SDRAM timing changes */ 42 43int omap_verify_speed(struct cpufreq_policy *policy) 44{ 45 if (freq_table) 46 return cpufreq_frequency_table_verify(policy, freq_table); 47 48 if (policy->cpu) 49 return -EINVAL; 50 51 cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq, 52 policy->cpuinfo.max_freq); 53 54 policy->min = clk_round_rate(mpu_clk, policy->min * 1000) / 1000; 55 policy->max = clk_round_rate(mpu_clk, policy->max * 1000) / 1000; 56 cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq, 57 policy->cpuinfo.max_freq); 58 return 0; 59} 60 61unsigned int omap_getspeed(unsigned int cpu) 62{ 63 unsigned long rate; 64 65 if (cpu) 66 return 0; 67 68 rate = clk_get_rate(mpu_clk) / 1000; 69 return rate; 70} 71 72static int omap_target(struct cpufreq_policy *policy, 73 unsigned int target_freq, 74 unsigned int relation) 75{ 76 struct cpufreq_freqs freqs; 77 int ret = 0; 78 79 /* Ensure desired rate is within allowed range. Some govenors 80 * (ondemand) will just pass target_freq=0 to get the minimum. */ 81 if (target_freq < policy->min) 82 target_freq = policy->min; 83 if (target_freq > policy->max) 84 target_freq = policy->max; 85 86 freqs.old = omap_getspeed(0); 87 freqs.new = clk_round_rate(mpu_clk, target_freq * 1000) / 1000; 88 freqs.cpu = 0; 89 90 if (freqs.old == freqs.new) 91 return ret; 92 93 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE); 94#ifdef CONFIG_CPU_FREQ_DEBUG 95 printk(KERN_DEBUG "cpufreq-omap: transition: %u --> %u\n", 96 freqs.old, freqs.new); 97#endif 98 ret = clk_set_rate(mpu_clk, freqs.new * 1000); 99 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE); 100 101 return ret; 102} 103 104static int __init omap_cpu_init(struct cpufreq_policy *policy) 105{ 106 int result = 0; 107 108 mpu_clk = clk_get(NULL, MPU_CLK); 109 if (IS_ERR(mpu_clk)) 110 return PTR_ERR(mpu_clk); 111 112 if (policy->cpu != 0) 113 return -EINVAL; 114 115 policy->cur = policy->min = policy->max = omap_getspeed(0); 116 117 clk_init_cpufreq_table(&freq_table); 118 if (freq_table) { 119 result = cpufreq_frequency_table_cpuinfo(policy, freq_table); 120 if (!result) 121 cpufreq_frequency_table_get_attr(freq_table, 122 policy->cpu); 123 } else { 124 policy->cpuinfo.min_freq = clk_round_rate(mpu_clk, 0) / 1000; 125 policy->cpuinfo.max_freq = clk_round_rate(mpu_clk, 126 VERY_HI_RATE) / 1000; 127 } 128 129 policy->cpuinfo.transition_latency = 300 * 1000; 130 131 return 0; 132} 133 134static int omap_cpu_exit(struct cpufreq_policy *policy) 135{ 136 clk_exit_cpufreq_table(&freq_table); 137 clk_put(mpu_clk); 138 return 0; 139} 140 141static struct freq_attr *omap_cpufreq_attr[] = { 142 &cpufreq_freq_attr_scaling_available_freqs, 143 NULL, 144}; 145 146static struct cpufreq_driver omap_driver = { 147 .flags = CPUFREQ_STICKY, 148 .verify = omap_verify_speed, 149 .target = omap_target, 150 .get = omap_getspeed, 151 .init = omap_cpu_init, 152 .exit = omap_cpu_exit, 153 .name = "omap", 154 .attr = omap_cpufreq_attr, 155}; 156 157static int __init omap_cpufreq_init(void) 158{ 159 return cpufreq_register_driver(&omap_driver); 160} 161 162arch_initcall(omap_cpufreq_init); 163 164/* 165 * if ever we want to remove this, upon cleanup call: 166 * 167 * cpufreq_unregister_driver() 168 * cpufreq_frequency_table_put_attr() 169 */ 170