drivers/cpufreq/omap-cpufreq.c

   1 /*
   2  *  CPU frequency scaling for OMAP using OPP information
   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 #include <linux/module.h>
  28
  29 #include <asm/system.h>
  30 #include <asm/smp_plat.h>
  31 #include <asm/cpu.h>
  32
  33 #include <plat/clock.h>
  34 #include <plat/omap-pm.h>
  35 #include <plat/common.h>
  36 #include <plat/omap_device.h>
  37
  38 #include <mach/hardware.h>
  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 atomic_t freq_table_users = ATOMIC_INIT(0);
  52 static struct clk *mpu_clk;
  53 static char *mpu_clk_name;
  54 static struct device *mpu_dev;
  55
  56 static int omap_verify_speed(struct cpufreq_policy *policy)
  57 {
  58         if (!freq_table)
  59                 return -EINVAL;
  60         return cpufreq_frequency_table_verify(policy, freq_table);
  61 }
  62
  63 static unsigned int omap_getspeed(unsigned int cpu)
  64 {
  65         unsigned long rate;
  66
  67         if (cpu >= NR_CPUS)
  68                 return 0;
  69
  70         rate = clk_get_rate(mpu_clk) / 1000;
  71         return rate;
  72 }
  73
  74 static int omap_target(struct cpufreq_policy *policy,
  75                        unsigned int target_freq,
  76                        unsigned int relation)
  77 {
  78         unsigned int i;
  79         int ret = 0;
  80         struct cpufreq_freqs freqs;
  81
  82         if (!freq_table) {
  83                 dev_err(mpu_dev, "%s: cpu%d: no freq table!\n", __func__,
  84                                 policy->cpu);
  85                 return -EINVAL;
  86         }
  87
  88         ret = cpufreq_frequency_table_target(policy, freq_table, target_freq,
  89                         relation, &i);
  90         if (ret) {
  91                 dev_dbg(mpu_dev, "%s: cpu%d: no freq match for %d(ret=%d)\n",
  92                         __func__, policy->cpu, target_freq, ret);
  93                 return ret;
  94         }
  95         freqs.new = freq_table[i].frequency;
  96         if (!freqs.new) {
  97                 dev_err(mpu_dev, "%s: cpu%d: no match for freq %d\n", __func__,
  98                         policy->cpu, target_freq);
  99                 return -EINVAL;
 100         }
 101
 102         freqs.old = omap_getspeed(policy->cpu);
 103         freqs.cpu = policy->cpu;
 104
 105         if (freqs.old == freqs.new && policy->cur == freqs.new)
 106                 return ret;
 107
 108         /* notifiers */
 109         for_each_cpu(i, policy->cpus) {
 110                 freqs.cpu = i;
 111                 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
 112         }
 113
 114 #ifdef CONFIG_CPU_FREQ_DEBUG
 115         pr_info("cpufreq-omap: transition: %u --> %u\n", freqs.old, freqs.new);
 116 #endif
 117
 118         ret = clk_set_rate(mpu_clk, freqs.new * 1000);
 119         freqs.new = omap_getspeed(policy->cpu);
 120
 121 #ifdef CONFIG_SMP
 122         /*
 123          * Note that loops_per_jiffy is not updated on SMP systems in
 124          * cpufreq driver. So, update the per-CPU loops_per_jiffy value
 125          * on frequency transition. We need to update all dependent CPUs.
 126          */
 127         for_each_cpu(i, policy->cpus) {
 128                 struct lpj_info *lpj = &per_cpu(lpj_ref, i);
 129                 if (!lpj->freq) {
 130                         lpj->ref = per_cpu(cpu_data, i).loops_per_jiffy;
 131                         lpj->freq = freqs.old;
 132                 }
 133
 134                 per_cpu(cpu_data, i).loops_per_jiffy =
 135                         cpufreq_scale(lpj->ref, lpj->freq, freqs.new);
 136         }
 137
 138         /* And don't forget to adjust the global one */
 139         if (!global_lpj_ref.freq) {
 140                 global_lpj_ref.ref = loops_per_jiffy;
 141                 global_lpj_ref.freq = freqs.old;
 142         }
 143         loops_per_jiffy = cpufreq_scale(global_lpj_ref.ref, global_lpj_ref.freq,
 144                                         freqs.new);
 145 #endif
 146
 147         /* notifiers */
 148         for_each_cpu(i, policy->cpus) {
 149                 freqs.cpu = i;
 150                 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
 151         }
 152
 153         return ret;
 154 }
 155
 156 static inline void freq_table_free(void)
 157 {
 158         if (atomic_dec_and_test(&freq_table_users))
 159                 opp_free_cpufreq_table(mpu_dev, &freq_table);
 160 }
 161
 162 static int __cpuinit omap_cpu_init(struct cpufreq_policy *policy)
 163 {
 164         int result = 0;
 165
 166         mpu_clk = clk_get(NULL, mpu_clk_name);
 167         if (IS_ERR(mpu_clk))
 168                 return PTR_ERR(mpu_clk);
 169
 170         if (policy->cpu >= NR_CPUS) {
 171                 result = -EINVAL;
 172                 goto fail_ck;
 173         }
 174
 175         policy->cur = policy->min = policy->max = omap_getspeed(policy->cpu);
 176
 177         if (atomic_inc_return(&freq_table_users) == 1)
 178                 result = opp_init_cpufreq_table(mpu_dev, &freq_table);
 179
 180         if (result) {
 181                 dev_err(mpu_dev, "%s: cpu%d: failed creating freq table[%d]\n",
 182                                 __func__, policy->cpu, result);
 183                 goto fail_ck;
 184         }
 185
 186         result = cpufreq_frequency_table_cpuinfo(policy, freq_table);
 187         if (result)
 188                 goto fail_table;
 189
 190         cpufreq_frequency_table_get_attr(freq_table, policy->cpu);
 191
 192         policy->min = policy->cpuinfo.min_freq;
 193         policy->max = policy->cpuinfo.max_freq;
 194         policy->cur = omap_getspeed(policy->cpu);
 195
 196         /*
 197          * On OMAP SMP configuartion, both processors share the voltage
 198          * and clock. So both CPUs needs to be scaled together and hence
 199          * needs software co-ordination. Use cpufreq affected_cpus
 200          * interface to handle this scenario. Additional is_smp() check
 201          * is to keep SMP_ON_UP build working.
 202          */
 203         if (is_smp()) {
 204                 policy->shared_type = CPUFREQ_SHARED_TYPE_ANY;
 205                 cpumask_setall(policy->cpus);
 206         }
 207
 208         /* FIXME: what's the actual transition time? */
 209         policy->cpuinfo.transition_latency = 300 * 1000;
 210
 211         return 0;
 212
 213 fail_table:
 214         freq_table_free();
 215 fail_ck:
 216         clk_put(mpu_clk);
 217         return result;
 218 }
 219
 220 static int omap_cpu_exit(struct cpufreq_policy *policy)
 221 {
 222         freq_table_free();
 223         clk_put(mpu_clk);
 224         return 0;
 225 }
 226
 227 static struct freq_attr *omap_cpufreq_attr[] = {
 228         &cpufreq_freq_attr_scaling_available_freqs,
 229         NULL,
 230 };
 231
 232 static struct cpufreq_driver omap_driver = {
 233         .flags          = CPUFREQ_STICKY,
 234         .verify         = omap_verify_speed,
 235         .target         = omap_target,
 236         .get            = omap_getspeed,
 237         .init           = omap_cpu_init,
 238         .exit           = omap_cpu_exit,
 239         .name           = "omap",
 240         .attr           = omap_cpufreq_attr,
 241 };
 242
 243 static int __init omap_cpufreq_init(void)
 244 {
 245         if (cpu_is_omap24xx())
 246                 mpu_clk_name = "virt_prcm_set";
 247         else if (cpu_is_omap34xx())
 248                 mpu_clk_name = "dpll1_ck";
 249         else if (cpu_is_omap44xx())
 250                 mpu_clk_name = "dpll_mpu_ck";
 251
 252         if (!mpu_clk_name) {
 253                 pr_err("%s: unsupported Silicon?\n", __func__);
 254                 return -EINVAL;
 255         }
 256
 257         mpu_dev = omap_device_get_by_hwmod_name("mpu");
 258         if (!mpu_dev) {
 259                 pr_warning("%s: unable to get the mpu device\n", __func__);
 260                 return -EINVAL;
 261         }
 262
 263         return cpufreq_register_driver(&omap_driver);
 264 }
 265
 266 static void __exit omap_cpufreq_exit(void)
 267 {
 268         cpufreq_unregister_driver(&omap_driver);
 269 }
 270
 271 MODULE_DESCRIPTION("cpufreq driver for OMAP SoCs");
 272 MODULE_LICENSE("GPL");
 273 module_init(omap_cpufreq_init);
 274 module_exit(omap_cpufreq_exit);