drivers/cpufreq/arm_big_little.c

   1 /*
   2  * ARM big.LITTLE Platforms CPUFreq support
   3  *
   4  * Copyright (C) 2013 ARM Ltd.
   5  * Sudeep KarkadaNagesha <sudeep.karkadanagesha@arm.com>
   6  *
   7  * Copyright (C) 2013 Linaro.
   8  * Viresh Kumar <viresh.kumar@linaro.org>
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License version 2 as
  12  * published by the Free Software Foundation.
  13  *
  14  * This program is distributed "as is" WITHOUT ANY WARRANTY of any
  15  * kind, whether express or implied; without even the implied warranty
  16  * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  17  * GNU General Public License for more details.
  18  */
  19
  20 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  21
  22 #include <linux/clk.h>
  23 #include <linux/cpu.h>
  24 #include <linux/cpufreq.h>
  25 #include <linux/cpumask.h>
  26 #include <linux/export.h>
  27 #include <linux/of_platform.h>
  28 #include <linux/opp.h>
  29 #include <linux/slab.h>
  30 #include <linux/topology.h>
  31 #include <linux/types.h>
  32
  33 #include "arm_big_little.h"
  34
  35 /* Currently we support only two clusters */
  36 #define MAX_CLUSTERS    2
  37
  38 static struct cpufreq_arm_bL_ops *arm_bL_ops;
  39 static struct clk *clk[MAX_CLUSTERS];
  40 static struct cpufreq_frequency_table *freq_table[MAX_CLUSTERS];
  41 static atomic_t cluster_usage[MAX_CLUSTERS] = {ATOMIC_INIT(0), ATOMIC_INIT(0)};
  42
  43 static unsigned int bL_cpufreq_get(unsigned int cpu)
  44 {
  45         u32 cur_cluster = cpu_to_cluster(cpu);
  46
  47         return clk_get_rate(clk[cur_cluster]) / 1000;
  48 }
  49
  50 /* Validate policy frequency range */
  51 static int bL_cpufreq_verify_policy(struct cpufreq_policy *policy)
  52 {
  53         u32 cur_cluster = cpu_to_cluster(policy->cpu);
  54
  55         return cpufreq_frequency_table_verify(policy, freq_table[cur_cluster]);
  56 }
  57
  58 /* Set clock frequency */
  59 static int bL_cpufreq_set_target(struct cpufreq_policy *policy,
  60                 unsigned int target_freq, unsigned int relation)
  61 {
  62         struct cpufreq_freqs freqs;
  63         u32 cpu = policy->cpu, freq_tab_idx, cur_cluster;
  64         int ret = 0;
  65
  66         cur_cluster = cpu_to_cluster(policy->cpu);
  67
  68         freqs.old = bL_cpufreq_get(policy->cpu);
  69
  70         /* Determine valid target frequency using freq_table */
  71         cpufreq_frequency_table_target(policy, freq_table[cur_cluster],
  72                         target_freq, relation, &freq_tab_idx);
  73         freqs.new = freq_table[cur_cluster][freq_tab_idx].frequency;
  74
  75         pr_debug("%s: cpu: %d, cluster: %d, oldfreq: %d, target freq: %d, new freq: %d\n",
  76                         __func__, cpu, cur_cluster, freqs.old, target_freq,
  77                         freqs.new);
  78
  79         if (freqs.old == freqs.new)
  80                 return 0;
  81
  82         cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);
  83
  84         ret = clk_set_rate(clk[cur_cluster], freqs.new * 1000);
  85         if (ret) {
  86                 pr_err("clk_set_rate failed: %d\n", ret);
  87                 return ret;
  88         }
  89
  90         policy->cur = freqs.new;
  91
  92         cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);
  93
  94         return ret;
  95 }
  96
  97 static void put_cluster_clk_and_freq_table(struct device *cpu_dev)
  98 {
  99         u32 cluster = cpu_to_cluster(cpu_dev->id);
 100
 101         if (!atomic_dec_return(&cluster_usage[cluster])) {
 102                 clk_put(clk[cluster]);
 103                 opp_free_cpufreq_table(cpu_dev, &freq_table[cluster]);
 104                 dev_dbg(cpu_dev, "%s: cluster: %d\n", __func__, cluster);
 105         }
 106 }
 107
 108 static int get_cluster_clk_and_freq_table(struct device *cpu_dev)
 109 {
 110         u32 cluster = cpu_to_cluster(cpu_dev->id);
 111         char name[14] = "cpu-cluster.";
 112         int ret;
 113
 114         if (atomic_inc_return(&cluster_usage[cluster]) != 1)
 115                 return 0;
 116
 117         ret = arm_bL_ops->init_opp_table(cpu_dev);
 118         if (ret) {
 119                 dev_err(cpu_dev, "%s: init_opp_table failed, cpu: %d, err: %d\n",
 120                                 __func__, cpu_dev->id, ret);
 121                 goto atomic_dec;
 122         }
 123
 124         ret = opp_init_cpufreq_table(cpu_dev, &freq_table[cluster]);
 125         if (ret) {
 126                 dev_err(cpu_dev, "%s: failed to init cpufreq table, cpu: %d, err: %d\n",
 127                                 __func__, cpu_dev->id, ret);
 128                 goto atomic_dec;
 129         }
 130
 131         name[12] = cluster + '0';
 132         clk[cluster] = clk_get_sys(name, NULL);
 133         if (!IS_ERR(clk[cluster])) {
 134                 dev_dbg(cpu_dev, "%s: clk: %p & freq table: %p, cluster: %d\n",
 135                                 __func__, clk[cluster], freq_table[cluster],
 136                                 cluster);
 137                 return 0;
 138         }
 139
 140         dev_err(cpu_dev, "%s: Failed to get clk for cpu: %d, cluster: %d\n",
 141                         __func__, cpu_dev->id, cluster);
 142         ret = PTR_ERR(clk[cluster]);
 143         opp_free_cpufreq_table(cpu_dev, &freq_table[cluster]);
 144
 145 atomic_dec:
 146         atomic_dec(&cluster_usage[cluster]);
 147         dev_err(cpu_dev, "%s: Failed to get data for cluster: %d\n", __func__,
 148                         cluster);
 149         return ret;
 150 }
 151
 152 /* Per-CPU initialization */
 153 static int bL_cpufreq_init(struct cpufreq_policy *policy)
 154 {
 155         u32 cur_cluster = cpu_to_cluster(policy->cpu);
 156         struct device *cpu_dev;
 157         int ret;
 158
 159         cpu_dev = get_cpu_device(policy->cpu);
 160         if (!cpu_dev) {
 161                 pr_err("%s: failed to get cpu%d device\n", __func__,
 162                                 policy->cpu);
 163                 return -ENODEV;
 164         }
 165
 166         ret = get_cluster_clk_and_freq_table(cpu_dev);
 167         if (ret)
 168                 return ret;
 169
 170         ret = cpufreq_frequency_table_cpuinfo(policy, freq_table[cur_cluster]);
 171         if (ret) {
 172                 dev_err(cpu_dev, "CPU %d, cluster: %d invalid freq table\n",
 173                                 policy->cpu, cur_cluster);
 174                 put_cluster_clk_and_freq_table(cpu_dev);
 175                 return ret;
 176         }
 177
 178         cpufreq_frequency_table_get_attr(freq_table[cur_cluster], policy->cpu);
 179
 180         if (arm_bL_ops->get_transition_latency)
 181                 policy->cpuinfo.transition_latency =
 182                         arm_bL_ops->get_transition_latency(cpu_dev);
 183         else
 184                 policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
 185
 186         policy->cur = bL_cpufreq_get(policy->cpu);
 187
 188         cpumask_copy(policy->cpus, topology_core_cpumask(policy->cpu));
 189
 190         dev_info(cpu_dev, "%s: CPU %d initialized\n", __func__, policy->cpu);
 191         return 0;
 192 }
 193
 194 static int bL_cpufreq_exit(struct cpufreq_policy *policy)
 195 {
 196         struct device *cpu_dev;
 197
 198         cpu_dev = get_cpu_device(policy->cpu);
 199         if (!cpu_dev) {
 200                 pr_err("%s: failed to get cpu%d device\n", __func__,
 201                                 policy->cpu);
 202                 return -ENODEV;
 203         }
 204
 205         put_cluster_clk_and_freq_table(cpu_dev);
 206         dev_dbg(cpu_dev, "%s: Exited, cpu: %d\n", __func__, policy->cpu);
 207
 208         return 0;
 209 }
 210
 211 /* Export freq_table to sysfs */
 212 static struct freq_attr *bL_cpufreq_attr[] = {
 213         &cpufreq_freq_attr_scaling_available_freqs,
 214         NULL,
 215 };
 216
 217 static struct cpufreq_driver bL_cpufreq_driver = {
 218         .name                   = "arm-big-little",
 219         .flags                  = CPUFREQ_STICKY,
 220         .verify                 = bL_cpufreq_verify_policy,
 221         .target                 = bL_cpufreq_set_target,
 222         .get                    = bL_cpufreq_get,
 223         .init                   = bL_cpufreq_init,
 224         .exit                   = bL_cpufreq_exit,
 225         .have_governor_per_policy = true,
 226         .attr                   = bL_cpufreq_attr,
 227 };
 228
 229 int bL_cpufreq_register(struct cpufreq_arm_bL_ops *ops)
 230 {
 231         int ret;
 232
 233         if (arm_bL_ops) {
 234                 pr_debug("%s: Already registered: %s, exiting\n", __func__,
 235                                 arm_bL_ops->name);
 236                 return -EBUSY;
 237         }
 238
 239         if (!ops || !strlen(ops->name) || !ops->init_opp_table) {
 240                 pr_err("%s: Invalid arm_bL_ops, exiting\n", __func__);
 241                 return -ENODEV;
 242         }
 243
 244         arm_bL_ops = ops;
 245
 246         ret = cpufreq_register_driver(&bL_cpufreq_driver);
 247         if (ret) {
 248                 pr_info("%s: Failed registering platform driver: %s, err: %d\n",
 249                                 __func__, ops->name, ret);
 250                 arm_bL_ops = NULL;
 251         } else {
 252                 pr_info("%s: Registered platform driver: %s\n", __func__,
 253                                 ops->name);
 254         }
 255
 256         return ret;
 257 }
 258 EXPORT_SYMBOL_GPL(bL_cpufreq_register);
 259
 260 void bL_cpufreq_unregister(struct cpufreq_arm_bL_ops *ops)
 261 {
 262         if (arm_bL_ops != ops) {
 263                 pr_err("%s: Registered with: %s, can't unregister, exiting\n",
 264                                 __func__, arm_bL_ops->name);
 265                 return;
 266         }
 267
 268         cpufreq_unregister_driver(&bL_cpufreq_driver);
 269         pr_info("%s: Un-registered platform driver: %s\n", __func__,
 270                         arm_bL_ops->name);
 271         arm_bL_ops = NULL;
 272 }
 273 EXPORT_SYMBOL_GPL(bL_cpufreq_unregister);