arch/arm/plat-omap/cpu-omap.c

   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  * Copyright (C) 2007-2008 Texas Instruments, Inc.
  12  * Updated to support OMAP3
  13  * Rajendra Nayak <rnayak@ti.com>
  14  *
  15  * This program is free software; you can redistribute it and/or modify
  16  * it under the terms of the GNU General Public License version 2 as
  17  * published by the Free Software Foundation.
  18  */
  19 #include <linux/types.h>
  20 #include <linux/kernel.h>
  21 #include <linux/sched.h>
  22 #include <linux/cpufreq.h>
  23 #include <linux/delay.h>
  24 #include <linux/init.h>
  25 #include <linux/err.h>
  26 #include <linux/clk.h>
  27 #include <linux/io.h>
  28
  29 #include <mach/hardware.h>
  30 #include <plat/clock.h>
  31 #include <asm/system.h>
  32
  33 #if defined(CONFIG_ARCH_OMAP3) && !defined(CONFIG_OMAP_PM_NONE)
  34 #include <plat/omap-pm.h>
  35 #endif
  36
  37 #define VERY_HI_RATE    900000000
  38
  39 static struct cpufreq_frequency_table *freq_table;
  40
  41 #ifdef CONFIG_ARCH_OMAP1
  42 #define MPU_CLK         "mpu"
  43 #elif CONFIG_ARCH_OMAP3
  44 #define MPU_CLK         "arm_fck"
  45 #else
  46 #define MPU_CLK         "virt_prcm_set"
  47 #endif
  48
  49 static struct clk *mpu_clk;
  50
  51 /* TODO: Add support for SDRAM timing changes */
  52
  53 int omap_verify_speed(struct cpufreq_policy *policy)
  54 {
  55         if (freq_table)
  56                 return cpufreq_frequency_table_verify(policy, freq_table);
  57
  58         if (policy->cpu)
  59                 return -EINVAL;
  60
  61         cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq,
  62                                      policy->cpuinfo.max_freq);
  63
  64         policy->min = clk_round_rate(mpu_clk, policy->min * 1000) / 1000;
  65         policy->max = clk_round_rate(mpu_clk, policy->max * 1000) / 1000;
  66         cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq,
  67                                      policy->cpuinfo.max_freq);
  68         return 0;
  69 }
  70
  71 unsigned int omap_getspeed(unsigned int cpu)
  72 {
  73         unsigned long rate;
  74
  75         if (cpu)
  76                 return 0;
  77
  78         rate = clk_get_rate(mpu_clk) / 1000;
  79         return rate;
  80 }
  81
  82 static int omap_target(struct cpufreq_policy *policy,
  83                        unsigned int target_freq,
  84                        unsigned int relation)
  85 {
  86 #ifdef CONFIG_ARCH_OMAP1
  87         struct cpufreq_freqs freqs;
  88 #endif
  89         int ret = 0;
  90
  91         /* Ensure desired rate is within allowed range.  Some govenors
  92          * (ondemand) will just pass target_freq=0 to get the minimum. */
  93         if (target_freq < policy->min)
  94                 target_freq = policy->min;
  95         if (target_freq > policy->max)
  96                 target_freq = policy->max;
  97
  98 #ifdef CONFIG_ARCH_OMAP1
  99         freqs.old = omap_getspeed(0);
 100         freqs.new = clk_round_rate(mpu_clk, target_freq * 1000) / 1000;
 101         freqs.cpu = 0;
 102
 103         if (freqs.old == freqs.new)
 104                 return ret;
 105         cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
 106 #ifdef CONFIG_CPU_FREQ_DEBUG
 107         printk(KERN_DEBUG "cpufreq-omap: transition: %u --> %u\n",
 108                freqs.old, freqs.new);
 109 #endif
 110         ret = clk_set_rate(mpu_clk, freqs.new * 1000);
 111         cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
 112 #elif defined(CONFIG_ARCH_OMAP3) && !defined(CONFIG_OMAP_PM_NONE)
 113         if (mpu_opps) {
 114                 int ind;
 115                 for (ind = 1; ind <= MAX_VDD1_OPP; ind++) {
 116                         if (mpu_opps[ind].rate/1000 >= target_freq) {
 117                                 omap_pm_cpu_set_freq
 118                                         (mpu_opps[ind].rate);
 119                                 break;
 120                         }
 121                 }
 122         }
 123 #endif
 124         return ret;
 125 }
 126
 127 static int __init omap_cpu_init(struct cpufreq_policy *policy)
 128 {
 129         int result = 0;
 130
 131         mpu_clk = clk_get(NULL, MPU_CLK);
 132         if (IS_ERR(mpu_clk))
 133                 return PTR_ERR(mpu_clk);
 134
 135         if (policy->cpu != 0)
 136                 return -EINVAL;
 137
 138         policy->cur = policy->min = policy->max = omap_getspeed(0);
 139
 140         clk_init_cpufreq_table(&freq_table);
 141         if (freq_table) {
 142                 result = cpufreq_frequency_table_cpuinfo(policy, freq_table);
 143                 if (!result)
 144                         cpufreq_frequency_table_get_attr(freq_table,
 145                                                         policy->cpu);
 146         } else {
 147                 policy->cpuinfo.min_freq = clk_round_rate(mpu_clk, 0) / 1000;
 148                 policy->cpuinfo.max_freq = clk_round_rate(mpu_clk,
 149                                                         VERY_HI_RATE) / 1000;
 150         }
 151
 152         clk_set_rate(mpu_clk, policy->cpuinfo.max_freq * 1000);
 153
 154         policy->min = policy->cpuinfo.min_freq;
 155         policy->max = policy->cpuinfo.max_freq;
 156         policy->cur = omap_getspeed(0);
 157
 158         /* FIXME: what's the actual transition time? */
 159         policy->cpuinfo.transition_latency = 10 * 1000 * 1000;
 160         return 0;
 161 }
 162
 163 static int omap_cpu_exit(struct cpufreq_policy *policy)
 164 {
 165         clk_put(mpu_clk);
 166         return 0;
 167 }
 168
 169 static struct freq_attr *omap_cpufreq_attr[] = {
 170         &cpufreq_freq_attr_scaling_available_freqs,
 171         NULL,
 172 };
 173
 174 static struct cpufreq_driver omap_driver = {
 175         .flags          = CPUFREQ_STICKY,
 176         .verify         = omap_verify_speed,
 177         .target         = omap_target,
 178         .get            = omap_getspeed,
 179         .init           = omap_cpu_init,
 180         .exit           = omap_cpu_exit,
 181         .name           = "omap",
 182         .attr           = omap_cpufreq_attr,
 183 };
 184
 185 static int __init omap_cpufreq_init(void)
 186 {
 187         return cpufreq_register_driver(&omap_driver);
 188 }
 189
 190 late_initcall(omap_cpufreq_init);
 191
 192 /*
 193  * if ever we want to remove this, upon cleanup call:
 194  *
 195  * cpufreq_unregister_driver()
 196  * cpufreq_frequency_table_put_attr()
 197  */
 198