Pileus Git - ~andy/linux/blob - 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
  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 #ifdef CONFIG_SMP
  39 struct lpj_info {
  40         unsigned long   ref;
  41         unsigned int    freq;
  42 };
  43
  44 static DEFINE_PER_CPU(struct lpj_info, lpj_ref);
  45 static struct lpj_info global_lpj_ref;
  46 #endif
  47
  48 static struct cpufreq_frequency_table *freq_table;
  49 static struct clk *mpu_clk;
  50 static char *mpu_clk_name;
  51 static struct device *mpu_dev;
  52
  53 static int omap_verify_speed(struct cpufreq_policy *policy)
  54 {
  55         if (!freq_table)
  56                 return -EINVAL;
  57         return cpufreq_frequency_table_verify(policy, freq_table);
  58 }
  59
  60 static unsigned int omap_getspeed(unsigned int cpu)
  61 {
  62         unsigned long rate;
  63
  64         if (cpu >= NR_CPUS)
  65                 return 0;
  66
  67         rate = clk_get_rate(mpu_clk) / 1000;
  68         return rate;
  69 }
  70
  71 static int omap_target(struct cpufreq_policy *policy,
  72                        unsigned int target_freq,
  73                        unsigned int relation)
  74 {
  75         unsigned int i;
  76         int ret = 0;
  77         struct cpufreq_freqs freqs;
  78
  79         if (!freq_table) {
  80                 dev_err(mpu_dev, "%s: cpu%d: no freq table!\n", __func__,
  81                                 policy->cpu);
  82                 return -EINVAL;
  83         }
  84
  85         ret = cpufreq_frequency_table_target(policy, freq_table, target_freq,
  86                         relation, &i);
  87         if (ret) {
  88                 dev_dbg(mpu_dev, "%s: cpu%d: no freq match for %d(ret=%d)\n",
  89                         __func__, policy->cpu, target_freq, ret);
  90                 return ret;
  91         }
  92         freqs.new = freq_table[i].frequency;
  93         if (!freqs.new) {
  94                 dev_err(mpu_dev, "%s: cpu%d: no match for freq %d\n", __func__,
  95                         policy->cpu, target_freq);
  96                 return -EINVAL;
  97         }
  98
  99         freqs.old = omap_getspeed(policy->cpu);
 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                 result = -EINVAL;
 163                 goto fail_ck;
 164         }
 165
 166         policy->cur = policy->min = policy->max = omap_getspeed(policy->cpu);
 167         result = opp_init_cpufreq_table(mpu_dev, &freq_table);
 168
 169         if (result) {
 170                 dev_err(mpu_dev, "%s: cpu%d: failed creating freq table[%d]\n",
 171                                 __func__, policy->cpu, result);
 172                 goto fail_ck;
 173         }
 174
 175         result = cpufreq_frequency_table_cpuinfo(policy, freq_table);
 176         if (!result)
 177                 cpufreq_frequency_table_get_attr(freq_table, policy->cpu);
 178         else
 179                 goto fail_ck;
 180
 181         policy->min = policy->cpuinfo.min_freq;
 182         policy->max = policy->cpuinfo.max_freq;
 183         policy->cur = omap_getspeed(policy->cpu);
 184
 185         /*
 186          * On OMAP SMP configuartion, both processors share the voltage
 187          * and clock. So both CPUs needs to be scaled together and hence
 188          * needs software co-ordination. Use cpufreq affected_cpus
 189          * interface to handle this scenario. Additional is_smp() check
 190          * is to keep SMP_ON_UP build working.
 191          */
 192         if (is_smp()) {
 193                 policy->shared_type = CPUFREQ_SHARED_TYPE_ANY;
 194                 cpumask_setall(policy->cpus);
 195         }
 196
 197         /* FIXME: what's the actual transition time? */
 198         policy->cpuinfo.transition_latency = 300 * 1000;
 199
 200         return 0;
 201
 202 fail_ck:
 203         clk_put(mpu_clk);
 204         return result;
 205 }
 206
 207 static int omap_cpu_exit(struct cpufreq_policy *policy)
 208 {
 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
 243         mpu_dev = omap2_get_mpuss_device();
 244         if (!mpu_dev) {
 245                 pr_warning("%s: unable to get the mpu device\n", __func__);
 246                 return -EINVAL;
 247         }
 248
 249         return cpufreq_register_driver(&omap_driver);
 250 }
 251
 252 static void __exit omap_cpufreq_exit(void)
 253 {
 254         cpufreq_unregister_driver(&omap_driver);
 255 }
 256
 257 MODULE_DESCRIPTION("cpufreq driver for OMAP SoCs");
 258 MODULE_LICENSE("GPL");
 259 module_init(omap_cpufreq_init);
 260 module_exit(omap_cpufreq_exit);