drivers/cpufreq/omap-cpufreq.c

   1 /*
   2  *  CPU frequency scaling for OMAP
   3  *
   4  *  Copyright (C) 2005 Nokia Corporation
   5  *  Written by Tony Lindgren <tony@atomide.com>
   6  *
   7  *  Based on cpu-sa1110.c, Copyright (C) 2001 Russell King
   8  *
   9  * Copyright (C) 2007-2011 Texas Instruments, Inc.
  10  * - OMAP3/4 support by Rajendra Nayak, Santosh Shilimkar
  11  *
  12  * This program is free software; you can redistribute it and/or modify
  13  * it under the terms of the GNU General Public License version 2 as
  14  * published by the Free Software Foundation.
  15  */
  16 #include <linux/types.h>
  17 #include <linux/kernel.h>
  18 #include <linux/sched.h>
  19 #include <linux/cpufreq.h>
  20 #include <linux/delay.h>
  21 #include <linux/init.h>
  22 #include <linux/err.h>
  23 #include <linux/clk.h>
  24 #include <linux/io.h>
  25 #include <linux/opp.h>
  26 #include <linux/cpu.h>
  27
  28 #include <asm/system.h>
  29 #include <asm/smp_plat.h>
  30 #include <asm/cpu.h>
  31
  32 #include <plat/clock.h>
  33 #include <plat/omap-pm.h>
  34 #include <plat/common.h>
  35
  36 #include <mach/hardware.h>
  37
  38 #define VERY_HI_RATE    900000000
  39
  40 #ifdef CONFIG_SMP
  41 struct lpj_info {
  42         unsigned long   ref;
  43         unsigned int    freq;
  44 };
  45
  46 static DEFINE_PER_CPU(struct lpj_info, lpj_ref);
  47 static struct lpj_info global_lpj_ref;
  48 #endif
  49
  50 static struct cpufreq_frequency_table *freq_table;
  51 static struct clk *mpu_clk;
  52 static char *mpu_clk_name;
  53 static struct device *mpu_dev;
  54
  55 static int omap_verify_speed(struct cpufreq_policy *policy)
  56 {
  57         if (freq_table)
  58                 return cpufreq_frequency_table_verify(policy, freq_table);
  59
  60         if (policy->cpu)
  61                 return -EINVAL;
  62
  63         cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq,
  64                                      policy->cpuinfo.max_freq);
  65
  66         policy->min = clk_round_rate(mpu_clk, policy->min * 1000) / 1000;
  67         policy->max = clk_round_rate(mpu_clk, policy->max * 1000) / 1000;
  68         cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq,
  69                                      policy->cpuinfo.max_freq);
  70         return 0;
  71 }
  72
  73 static unsigned int omap_getspeed(unsigned int cpu)
  74 {
  75         unsigned long rate;
  76
  77         if (cpu >= NR_CPUS)
  78                 return 0;
  79
  80         rate = clk_get_rate(mpu_clk) / 1000;
  81         return rate;
  82 }
  83
  84 static int omap_target(struct cpufreq_policy *policy,
  85                        unsigned int target_freq,
  86                        unsigned int relation)
  87 {
  88         int i, ret = 0;
  89         struct cpufreq_freqs freqs;
  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         freqs.old = omap_getspeed(policy->cpu);
  99         freqs.new = clk_round_rate(mpu_clk, target_freq * 1000) / 1000;
 100         freqs.cpu = policy->cpu;
 101
 102         if (freqs.old == freqs.new && policy->cur == freqs.new)
 103                 return ret;
 104
 105         /* notifiers */
 106         for_each_cpu(i, policy->cpus) {
 107                 freqs.cpu = i;
 108                 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
 109         }
 110
 111 #ifdef CONFIG_CPU_FREQ_DEBUG
 112         pr_info("cpufreq-omap: transition: %u --> %u\n", freqs.old, freqs.new);
 113 #endif
 114
 115         ret = clk_set_rate(mpu_clk, freqs.new * 1000);
 116         freqs.new = omap_getspeed(policy->cpu);
 117
 118 #ifdef CONFIG_SMP
 119         /*
 120          * Note that loops_per_jiffy is not updated on SMP systems in
 121          * cpufreq driver. So, update the per-CPU loops_per_jiffy value
 122          * on frequency transition. We need to update all dependent CPUs.
 123          */
 124         for_each_cpu(i, policy->cpus) {
 125                 struct lpj_info *lpj = &per_cpu(lpj_ref, i);
 126                 if (!lpj->freq) {
 127                         lpj->ref = per_cpu(cpu_data, i).loops_per_jiffy;
 128                         lpj->freq = freqs.old;
 129                 }
 130
 131                 per_cpu(cpu_data, i).loops_per_jiffy =
 132                         cpufreq_scale(lpj->ref, lpj->freq, freqs.new);
 133         }
 134
 135         /* And don't forget to adjust the global one */
 136         if (!global_lpj_ref.freq) {
 137                 global_lpj_ref.ref = loops_per_jiffy;
 138                 global_lpj_ref.freq = freqs.old;
 139         }
 140         loops_per_jiffy = cpufreq_scale(global_lpj_ref.ref, global_lpj_ref.freq,
 141                                         freqs.new);
 142 #endif
 143
 144         /* notifiers */
 145         for_each_cpu(i, policy->cpus) {
 146                 freqs.cpu = i;
 147                 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
 148         }
 149
 150         return ret;
 151 }
 152
 153 static int __cpuinit omap_cpu_init(struct cpufreq_policy *policy)
 154 {
 155         int result = 0;
 156
 157         mpu_clk = clk_get(NULL, mpu_clk_name);
 158         if (IS_ERR(mpu_clk))
 159                 return PTR_ERR(mpu_clk);
 160
 161         if (policy->cpu >= NR_CPUS)
 162                 return -EINVAL;
 163
 164         policy->cur = policy->min = policy->max = omap_getspeed(policy->cpu);
 165         opp_init_cpufreq_table(mpu_dev, &freq_table);
 166
 167         if (freq_table) {
 168                 result = cpufreq_frequency_table_cpuinfo(policy, freq_table);
 169                 if (!result)
 170                         cpufreq_frequency_table_get_attr(freq_table,
 171                                                         policy->cpu);
 172         } else {
 173                 policy->cpuinfo.min_freq = clk_round_rate(mpu_clk, 0) / 1000;
 174                 policy->cpuinfo.max_freq = clk_round_rate(mpu_clk,
 175                                                         VERY_HI_RATE) / 1000;
 176         }
 177
 178         policy->min = policy->cpuinfo.min_freq;
 179         policy->max = policy->cpuinfo.max_freq;
 180         policy->cur = omap_getspeed(policy->cpu);
 181
 182         /*
 183          * On OMAP SMP configuartion, both processors share the voltage
 184          * and clock. So both CPUs needs to be scaled together and hence
 185          * needs software co-ordination. Use cpufreq affected_cpus
 186          * interface to handle this scenario. Additional is_smp() check
 187          * is to keep SMP_ON_UP build working.
 188          */
 189         if (is_smp()) {
 190                 policy->shared_type = CPUFREQ_SHARED_TYPE_ANY;
 191                 cpumask_setall(policy->cpus);
 192         }
 193
 194         /* FIXME: what's the actual transition time? */
 195         policy->cpuinfo.transition_latency = 300 * 1000;
 196
 197         return 0;
 198 }
 199
 200 static int omap_cpu_exit(struct cpufreq_policy *policy)
 201 {
 202         clk_exit_cpufreq_table(&freq_table);
 203         clk_put(mpu_clk);
 204         return 0;
 205 }
 206
 207 static struct freq_attr *omap_cpufreq_attr[] = {
 208         &cpufreq_freq_attr_scaling_available_freqs,
 209         NULL,
 210 };
 211
 212 static struct cpufreq_driver omap_driver = {
 213         .flags          = CPUFREQ_STICKY,
 214         .verify         = omap_verify_speed,
 215         .target         = omap_target,
 216         .get            = omap_getspeed,
 217         .init           = omap_cpu_init,
 218         .exit           = omap_cpu_exit,
 219         .name           = "omap",
 220         .attr           = omap_cpufreq_attr,
 221 };
 222
 223 static int __init omap_cpufreq_init(void)
 224 {
 225         if (cpu_is_omap24xx())
 226                 mpu_clk_name = "virt_prcm_set";
 227         else if (cpu_is_omap34xx())
 228                 mpu_clk_name = "dpll1_ck";
 229         else if (cpu_is_omap44xx())
 230                 mpu_clk_name = "dpll_mpu_ck";
 231
 232         if (!mpu_clk_name) {
 233                 pr_err("%s: unsupported Silicon?\n", __func__);
 234                 return -EINVAL;
 235         }
 236
 237         mpu_dev = omap2_get_mpuss_device();
 238         if (!mpu_dev) {
 239                 pr_warning("%s: unable to get the mpu device\n", __func__);
 240                 return -EINVAL;
 241         }
 242
 243         return cpufreq_register_driver(&omap_driver);
 244 }
 245
 246 static void __exit omap_cpufreq_exit(void)
 247 {
 248         cpufreq_unregister_driver(&omap_driver);
 249 }
 250
 251 MODULE_DESCRIPTION("cpufreq driver for OMAP SoCs");
 252 MODULE_LICENSE("GPL");
 253 module_init(omap_cpufreq_init);
 254 module_exit(omap_cpufreq_exit);