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