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 #include <linux/regulator/consumer.h>
  29
  30 #include <asm/system.h>
  31 #include <asm/smp_plat.h>
  32 #include <asm/cpu.h>
  33
  34 #include <plat/clock.h>
  35 #include <plat/omap-pm.h>
  36 #include <plat/common.h>
  37 #include <plat/omap_device.h>
  38
  39 #include <mach/hardware.h>
  40
  41 /* OPP tolerance in percentage */
  42 #define OPP_TOLERANCE   4
  43
  44 #ifdef CONFIG_SMP
  45 struct lpj_info {
  46         unsigned long   ref;
  47         unsigned int    freq;
  48 };
  49
  50 static DEFINE_PER_CPU(struct lpj_info, lpj_ref);
  51 static struct lpj_info global_lpj_ref;
  52 #endif
  53
  54 static struct cpufreq_frequency_table *freq_table;
  55 static atomic_t freq_table_users = ATOMIC_INIT(0);
  56 static struct clk *mpu_clk;
  57 static char *mpu_clk_name;
  58 static struct device *mpu_dev;
  59 static struct regulator *mpu_reg;
  60
  61 static int omap_verify_speed(struct cpufreq_policy *policy)
  62 {
  63         if (!freq_table)
  64                 return -EINVAL;
  65         return cpufreq_frequency_table_verify(policy, freq_table);
  66 }
  67
  68 static unsigned int omap_getspeed(unsigned int cpu)
  69 {
  70         unsigned long rate;
  71
  72         if (cpu >= NR_CPUS)
  73                 return 0;
  74
  75         rate = clk_get_rate(mpu_clk) / 1000;
  76         return rate;
  77 }
  78
  79 static int omap_target(struct cpufreq_policy *policy,
  80                        unsigned int target_freq,
  81                        unsigned int relation)
  82 {
  83         unsigned int i;
  84         int r, ret = 0;
  85         struct cpufreq_freqs freqs;
  86         struct opp *opp;
  87         unsigned long freq, volt = 0, volt_old = 0, tol = 0;
  88
  89         if (!freq_table) {
  90                 dev_err(mpu_dev, "%s: cpu%d: no freq table!\n", __func__,
  91                                 policy->cpu);
  92                 return -EINVAL;
  93         }
  94
  95         ret = cpufreq_frequency_table_target(policy, freq_table, target_freq,
  96                         relation, &i);
  97         if (ret) {
  98                 dev_dbg(mpu_dev, "%s: cpu%d: no freq match for %d(ret=%d)\n",
  99                         __func__, policy->cpu, target_freq, ret);
 100                 return ret;
 101         }
 102         freqs.new = freq_table[i].frequency;
 103         if (!freqs.new) {
 104                 dev_err(mpu_dev, "%s: cpu%d: no match for freq %d\n", __func__,
 105                         policy->cpu, target_freq);
 106                 return -EINVAL;
 107         }
 108
 109         freqs.old = omap_getspeed(policy->cpu);
 110         freqs.cpu = policy->cpu;
 111
 112         if (freqs.old == freqs.new && policy->cur == freqs.new)
 113                 return ret;
 114
 115         /* notifiers */
 116         for_each_cpu(i, policy->cpus) {
 117                 freqs.cpu = i;
 118                 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
 119         }
 120
 121         freq = freqs.new * 1000;
 122
 123         if (mpu_reg) {
 124                 opp = opp_find_freq_ceil(mpu_dev, &freq);
 125                 if (IS_ERR(opp)) {
 126                         dev_err(mpu_dev, "%s: unable to find MPU OPP for %d\n",
 127                                 __func__, freqs.new);
 128                         return -EINVAL;
 129                 }
 130                 volt = opp_get_voltage(opp);
 131                 tol = volt * OPP_TOLERANCE / 100;
 132                 volt_old = regulator_get_voltage(mpu_reg);
 133         }
 134
 135         dev_dbg(mpu_dev, "cpufreq-omap: %u MHz, %ld mV --> %u MHz, %ld mV\n",
 136                 freqs.old / 1000, volt_old ? volt_old / 1000 : -1,
 137                 freqs.new / 1000, volt ? volt / 1000 : -1);
 138
 139         /* scaling up?  scale voltage before frequency */
 140         if (mpu_reg && (freqs.new > freqs.old)) {
 141                 r = regulator_set_voltage(mpu_reg, volt - tol, volt + tol);
 142                 if (r < 0) {
 143                         dev_warn(mpu_dev, "%s: unable to scale voltage up.\n",
 144                                  __func__);
 145                         freqs.new = freqs.old;
 146                         goto done;
 147                 }
 148         }
 149
 150         ret = clk_set_rate(mpu_clk, freqs.new * 1000);
 151
 152         /* scaling down?  scale voltage after frequency */
 153         if (mpu_reg && (freqs.new < freqs.old)) {
 154                 r = regulator_set_voltage(mpu_reg, volt - tol, volt + tol);
 155                 if (r < 0) {
 156                         dev_warn(mpu_dev, "%s: unable to scale voltage down.\n",
 157                                  __func__);
 158                         ret = clk_set_rate(mpu_clk, freqs.old * 1000);
 159                         freqs.new = freqs.old;
 160                         goto done;
 161                 }
 162         }
 163
 164         freqs.new = omap_getspeed(policy->cpu);
 165 #ifdef CONFIG_SMP
 166         /*
 167          * Note that loops_per_jiffy is not updated on SMP systems in
 168          * cpufreq driver. So, update the per-CPU loops_per_jiffy value
 169          * on frequency transition. We need to update all dependent CPUs.
 170          */
 171         for_each_cpu(i, policy->cpus) {
 172                 struct lpj_info *lpj = &per_cpu(lpj_ref, i);
 173                 if (!lpj->freq) {
 174                         lpj->ref = per_cpu(cpu_data, i).loops_per_jiffy;
 175                         lpj->freq = freqs.old;
 176                 }
 177
 178                 per_cpu(cpu_data, i).loops_per_jiffy =
 179                         cpufreq_scale(lpj->ref, lpj->freq, freqs.new);
 180         }
 181
 182         /* And don't forget to adjust the global one */
 183         if (!global_lpj_ref.freq) {
 184                 global_lpj_ref.ref = loops_per_jiffy;
 185                 global_lpj_ref.freq = freqs.old;
 186         }
 187         loops_per_jiffy = cpufreq_scale(global_lpj_ref.ref, global_lpj_ref.freq,
 188                                         freqs.new);
 189 #endif
 190
 191 done:
 192         /* notifiers */
 193         for_each_cpu(i, policy->cpus) {
 194                 freqs.cpu = i;
 195                 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
 196         }
 197
 198         return ret;
 199 }
 200
 201 static inline void freq_table_free(void)
 202 {
 203         if (atomic_dec_and_test(&freq_table_users))
 204                 opp_free_cpufreq_table(mpu_dev, &freq_table);
 205 }
 206
 207 static int __cpuinit omap_cpu_init(struct cpufreq_policy *policy)
 208 {
 209         int result = 0;
 210
 211         mpu_clk = clk_get(NULL, mpu_clk_name);
 212         if (IS_ERR(mpu_clk))
 213                 return PTR_ERR(mpu_clk);
 214
 215         if (policy->cpu >= NR_CPUS) {
 216                 result = -EINVAL;
 217                 goto fail_ck;
 218         }
 219
 220         policy->cur = policy->min = policy->max = omap_getspeed(policy->cpu);
 221
 222         if (atomic_inc_return(&freq_table_users) == 1)
 223                 result = opp_init_cpufreq_table(mpu_dev, &freq_table);
 224
 225         if (result) {
 226                 dev_err(mpu_dev, "%s: cpu%d: failed creating freq table[%d]\n",
 227                                 __func__, policy->cpu, result);
 228                 goto fail_ck;
 229         }
 230
 231         result = cpufreq_frequency_table_cpuinfo(policy, freq_table);
 232         if (result)
 233                 goto fail_table;
 234
 235         cpufreq_frequency_table_get_attr(freq_table, policy->cpu);
 236
 237         policy->min = policy->cpuinfo.min_freq;
 238         policy->max = policy->cpuinfo.max_freq;
 239         policy->cur = omap_getspeed(policy->cpu);
 240
 241         /*
 242          * On OMAP SMP configuartion, both processors share the voltage
 243          * and clock. So both CPUs needs to be scaled together and hence
 244          * needs software co-ordination. Use cpufreq affected_cpus
 245          * interface to handle this scenario. Additional is_smp() check
 246          * is to keep SMP_ON_UP build working.
 247          */
 248         if (is_smp()) {
 249                 policy->shared_type = CPUFREQ_SHARED_TYPE_ANY;
 250                 cpumask_setall(policy->cpus);
 251         }
 252
 253         /* FIXME: what's the actual transition time? */
 254         policy->cpuinfo.transition_latency = 300 * 1000;
 255
 256         return 0;
 257
 258 fail_table:
 259         freq_table_free();
 260 fail_ck:
 261         clk_put(mpu_clk);
 262         return result;
 263 }
 264
 265 static int omap_cpu_exit(struct cpufreq_policy *policy)
 266 {
 267         freq_table_free();
 268         clk_put(mpu_clk);
 269         return 0;
 270 }
 271
 272 static struct freq_attr *omap_cpufreq_attr[] = {
 273         &cpufreq_freq_attr_scaling_available_freqs,
 274         NULL,
 275 };
 276
 277 static struct cpufreq_driver omap_driver = {
 278         .flags          = CPUFREQ_STICKY,
 279         .verify         = omap_verify_speed,
 280         .target         = omap_target,
 281         .get            = omap_getspeed,
 282         .init           = omap_cpu_init,
 283         .exit           = omap_cpu_exit,
 284         .name           = "omap",
 285         .attr           = omap_cpufreq_attr,
 286 };
 287
 288 static int __init omap_cpufreq_init(void)
 289 {
 290         if (cpu_is_omap24xx())
 291                 mpu_clk_name = "virt_prcm_set";
 292         else if (cpu_is_omap34xx())
 293                 mpu_clk_name = "dpll1_ck";
 294         else if (cpu_is_omap44xx())
 295                 mpu_clk_name = "dpll_mpu_ck";
 296
 297         if (!mpu_clk_name) {
 298                 pr_err("%s: unsupported Silicon?\n", __func__);
 299                 return -EINVAL;
 300         }
 301
 302         mpu_dev = omap_device_get_by_hwmod_name("mpu");
 303         if (!mpu_dev) {
 304                 pr_warning("%s: unable to get the mpu device\n", __func__);
 305                 return -EINVAL;
 306         }
 307
 308         mpu_reg = regulator_get(mpu_dev, "vcc");
 309         if (IS_ERR(mpu_reg)) {
 310                 pr_warning("%s: unable to get MPU regulator\n", __func__);
 311                 mpu_reg = NULL;
 312         } else {
 313                 /*
 314                  * Ensure physical regulator is present.
 315                  * (e.g. could be dummy regulator.)
 316                  */
 317                 if (regulator_get_voltage(mpu_reg) < 0) {
 318                         pr_warn("%s: physical regulator not present for MPU\n",
 319                                 __func__);
 320                         regulator_put(mpu_reg);
 321                         mpu_reg = NULL;
 322                 }
 323         }
 324
 325         return cpufreq_register_driver(&omap_driver);
 326 }
 327
 328 static void __exit omap_cpufreq_exit(void)
 329 {
 330         cpufreq_unregister_driver(&omap_driver);
 331 }
 332
 333 MODULE_DESCRIPTION("cpufreq driver for OMAP SoCs");
 334 MODULE_LICENSE("GPL");
 335 module_init(omap_cpufreq_init);
 336 module_exit(omap_cpufreq_exit);