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
  54 static int omap_verify_speed(struct cpufreq_policy *policy)
  55 {
  56         if (freq_table)
  57                 return cpufreq_frequency_table_verify(policy, freq_table);
  58
  59         if (policy->cpu)
  60                 return -EINVAL;
  61
  62         cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq,
  63                                      policy->cpuinfo.max_freq);
  64
  65         policy->min = clk_round_rate(mpu_clk, policy->min * 1000) / 1000;
  66         policy->max = clk_round_rate(mpu_clk, policy->max * 1000) / 1000;
  67         cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq,
  68                                      policy->cpuinfo.max_freq);
  69         return 0;
  70 }
  71
  72 static unsigned int omap_getspeed(unsigned int cpu)
  73 {
  74         unsigned long rate;
  75
  76         if (cpu >= NR_CPUS)
  77                 return 0;
  78
  79         rate = clk_get_rate(mpu_clk) / 1000;
  80         return rate;
  81 }
  82
  83 static int omap_target(struct cpufreq_policy *policy,
  84                        unsigned int target_freq,
  85                        unsigned int relation)
  86 {
  87         int i, ret = 0;
  88         struct cpufreq_freqs freqs;
  89
  90         /* Ensure desired rate is within allowed range.  Some govenors
  91          * (ondemand) will just pass target_freq=0 to get the minimum. */
  92         if (target_freq < policy->min)
  93                 target_freq = policy->min;
  94         if (target_freq > policy->max)
  95                 target_freq = policy->max;
  96
  97         freqs.old = omap_getspeed(policy->cpu);
  98         freqs.new = clk_round_rate(mpu_clk, target_freq * 1000) / 1000;
  99         freqs.cpu = policy->cpu;
 100
 101         if (freqs.old == freqs.new && policy->cur == freqs.new)
 102                 return ret;
 103
 104         /* notifiers */
 105         for_each_cpu(i, policy->cpus) {
 106                 freqs.cpu = i;
 107                 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
 108         }
 109
 110 #ifdef CONFIG_CPU_FREQ_DEBUG
 111         pr_info("cpufreq-omap: transition: %u --> %u\n", freqs.old, freqs.new);
 112 #endif
 113
 114         ret = clk_set_rate(mpu_clk, freqs.new * 1000);
 115         freqs.new = omap_getspeed(policy->cpu);
 116
 117 #ifdef CONFIG_SMP
 118         /*
 119          * Note that loops_per_jiffy is not updated on SMP systems in
 120          * cpufreq driver. So, update the per-CPU loops_per_jiffy value
 121          * on frequency transition. We need to update all dependent CPUs.
 122          */
 123         for_each_cpu(i, policy->cpus) {
 124                 struct lpj_info *lpj = &per_cpu(lpj_ref, i);
 125                 if (!lpj->freq) {
 126                         lpj->ref = per_cpu(cpu_data, i).loops_per_jiffy;
 127                         lpj->freq = freqs.old;
 128                 }
 129
 130                 per_cpu(cpu_data, i).loops_per_jiffy =
 131                         cpufreq_scale(lpj->ref, lpj->freq, freqs.new);
 132         }
 133
 134         /* And don't forget to adjust the global one */
 135         if (!global_lpj_ref.freq) {
 136                 global_lpj_ref.ref = loops_per_jiffy;
 137                 global_lpj_ref.freq = freqs.old;
 138         }
 139         loops_per_jiffy = cpufreq_scale(global_lpj_ref.ref, global_lpj_ref.freq,
 140                                         freqs.new);
 141 #endif
 142
 143         /* notifiers */
 144         for_each_cpu(i, policy->cpus) {
 145                 freqs.cpu = i;
 146                 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
 147         }
 148
 149         return ret;
 150 }
 151
 152 static int __cpuinit omap_cpu_init(struct cpufreq_policy *policy)
 153 {
 154         int result = 0;
 155         struct device *mpu_dev;
 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         mpu_dev = omap2_get_mpuss_device();
 166
 167         if (!mpu_dev) {
 168                 pr_warning("%s: unable to get the mpu device\n", __func__);
 169                 return -EINVAL;
 170         }
 171         opp_init_cpufreq_table(mpu_dev, &freq_table);
 172
 173         if (freq_table) {
 174                 result = cpufreq_frequency_table_cpuinfo(policy, freq_table);
 175                 if (!result)
 176                         cpufreq_frequency_table_get_attr(freq_table,
 177                                                         policy->cpu);
 178         } else {
 179                 policy->cpuinfo.min_freq = clk_round_rate(mpu_clk, 0) / 1000;
 180                 policy->cpuinfo.max_freq = clk_round_rate(mpu_clk,
 181                                                         VERY_HI_RATE) / 1000;
 182         }
 183
 184         policy->min = policy->cpuinfo.min_freq;
 185         policy->max = policy->cpuinfo.max_freq;
 186         policy->cur = omap_getspeed(policy->cpu);
 187
 188         /*
 189          * On OMAP SMP configuartion, both processors share the voltage
 190          * and clock. So both CPUs needs to be scaled together and hence
 191          * needs software co-ordination. Use cpufreq affected_cpus
 192          * interface to handle this scenario. Additional is_smp() check
 193          * is to keep SMP_ON_UP build working.
 194          */
 195         if (is_smp()) {
 196                 policy->shared_type = CPUFREQ_SHARED_TYPE_ANY;
 197                 cpumask_setall(policy->cpus);
 198         }
 199
 200         /* FIXME: what's the actual transition time? */
 201         policy->cpuinfo.transition_latency = 300 * 1000;
 202
 203         return 0;
 204 }
 205
 206 static int omap_cpu_exit(struct cpufreq_policy *policy)
 207 {
 208         clk_exit_cpufreq_table(&freq_table);
 209         clk_put(mpu_clk);
 210         return 0;
 211 }
 212
 213 static struct freq_attr *omap_cpufreq_attr[] = {
 214         &cpufreq_freq_attr_scaling_available_freqs,
 215         NULL,
 216 };
 217
 218 static struct cpufreq_driver omap_driver = {
 219         .flags          = CPUFREQ_STICKY,
 220         .verify         = omap_verify_speed,
 221         .target         = omap_target,
 222         .get            = omap_getspeed,
 223         .init           = omap_cpu_init,
 224         .exit           = omap_cpu_exit,
 225         .name           = "omap",
 226         .attr           = omap_cpufreq_attr,
 227 };
 228
 229 static int __init omap_cpufreq_init(void)
 230 {
 231         if (cpu_is_omap24xx())
 232                 mpu_clk_name = "virt_prcm_set";
 233         else if (cpu_is_omap34xx())
 234                 mpu_clk_name = "dpll1_ck";
 235         else if (cpu_is_omap44xx())
 236                 mpu_clk_name = "dpll_mpu_ck";
 237
 238         if (!mpu_clk_name) {
 239                 pr_err("%s: unsupported Silicon?\n", __func__);
 240                 return -EINVAL;
 241         }
 242         return cpufreq_register_driver(&omap_driver);
 243 }
 244
 245 static void __exit omap_cpufreq_exit(void)
 246 {
 247         cpufreq_unregister_driver(&omap_driver);
 248 }
 249
 250 MODULE_DESCRIPTION("cpufreq driver for OMAP SoCs");
 251 MODULE_LICENSE("GPL");
 252 module_init(omap_cpufreq_init);
 253 module_exit(omap_cpufreq_exit);