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                 freqs.new = freqs.old;
  88         }
  89
  90         cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);
  91
  92         return ret;
  93 }
  94
  95 static void put_cluster_clk_and_freq_table(struct device *cpu_dev)
  96 {
  97         u32 cluster = cpu_to_cluster(cpu_dev->id);
  98
  99         if (!atomic_dec_return(&cluster_usage[cluster])) {
 100                 clk_put(clk[cluster]);
 101                 opp_free_cpufreq_table(cpu_dev, &freq_table[cluster]);
 102                 dev_dbg(cpu_dev, "%s: cluster: %d\n", __func__, cluster);
 103         }
 104 }
 105
 106 static int get_cluster_clk_and_freq_table(struct device *cpu_dev)
 107 {
 108         u32 cluster = cpu_to_cluster(cpu_dev->id);
 109         char name[14] = "cpu-cluster.";
 110         int ret;
 111
 112         if (atomic_inc_return(&cluster_usage[cluster]) != 1)
 113                 return 0;
 114
 115         ret = arm_bL_ops->init_opp_table(cpu_dev);
 116         if (ret) {
 117                 dev_err(cpu_dev, "%s: init_opp_table failed, cpu: %d, err: %d\n",
 118                                 __func__, cpu_dev->id, ret);
 119                 goto atomic_dec;
 120         }
 121
 122         ret = opp_init_cpufreq_table(cpu_dev, &freq_table[cluster]);
 123         if (ret) {
 124                 dev_err(cpu_dev, "%s: failed to init cpufreq table, cpu: %d, err: %d\n",
 125                                 __func__, cpu_dev->id, ret);
 126                 goto atomic_dec;
 127         }
 128
 129         name[12] = cluster + '0';
 130         clk[cluster] = clk_get_sys(name, NULL);
 131         if (!IS_ERR(clk[cluster])) {
 132                 dev_dbg(cpu_dev, "%s: clk: %p & freq table: %p, cluster: %d\n",
 133                                 __func__, clk[cluster], freq_table[cluster],
 134                                 cluster);
 135                 return 0;
 136         }
 137
 138         dev_err(cpu_dev, "%s: Failed to get clk for cpu: %d, cluster: %d\n",
 139                         __func__, cpu_dev->id, cluster);
 140         ret = PTR_ERR(clk[cluster]);
 141         opp_free_cpufreq_table(cpu_dev, &freq_table[cluster]);
 142
 143 atomic_dec:
 144         atomic_dec(&cluster_usage[cluster]);
 145         dev_err(cpu_dev, "%s: Failed to get data for cluster: %d\n", __func__,
 146                         cluster);
 147         return ret;
 148 }
 149
 150 /* Per-CPU initialization */
 151 static int bL_cpufreq_init(struct cpufreq_policy *policy)
 152 {
 153         u32 cur_cluster = cpu_to_cluster(policy->cpu);
 154         struct device *cpu_dev;
 155         int ret;
 156
 157         cpu_dev = get_cpu_device(policy->cpu);
 158         if (!cpu_dev) {
 159                 pr_err("%s: failed to get cpu%d device\n", __func__,
 160                                 policy->cpu);
 161                 return -ENODEV;
 162         }
 163
 164         ret = get_cluster_clk_and_freq_table(cpu_dev);
 165         if (ret)
 166                 return ret;
 167
 168         ret = cpufreq_frequency_table_cpuinfo(policy, freq_table[cur_cluster]);
 169         if (ret) {
 170                 dev_err(cpu_dev, "CPU %d, cluster: %d invalid freq table\n",
 171                                 policy->cpu, cur_cluster);
 172                 put_cluster_clk_and_freq_table(cpu_dev);
 173                 return ret;
 174         }
 175
 176         cpufreq_frequency_table_get_attr(freq_table[cur_cluster], policy->cpu);
 177
 178         if (arm_bL_ops->get_transition_latency)
 179                 policy->cpuinfo.transition_latency =
 180                         arm_bL_ops->get_transition_latency(cpu_dev);
 181         else
 182                 policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
 183
 184         policy->cur = bL_cpufreq_get(policy->cpu);
 185
 186         cpumask_copy(policy->cpus, topology_core_cpumask(policy->cpu));
 187
 188         dev_info(cpu_dev, "%s: CPU %d initialized\n", __func__, policy->cpu);
 189         return 0;
 190 }
 191
 192 static int bL_cpufreq_exit(struct cpufreq_policy *policy)
 193 {
 194         struct device *cpu_dev;
 195
 196         cpu_dev = get_cpu_device(policy->cpu);
 197         if (!cpu_dev) {
 198                 pr_err("%s: failed to get cpu%d device\n", __func__,
 199                                 policy->cpu);
 200                 return -ENODEV;
 201         }
 202
 203         put_cluster_clk_and_freq_table(cpu_dev);
 204         dev_dbg(cpu_dev, "%s: Exited, cpu: %d\n", __func__, policy->cpu);
 205
 206         return 0;
 207 }
 208
 209 /* Export freq_table to sysfs */
 210 static struct freq_attr *bL_cpufreq_attr[] = {
 211         &cpufreq_freq_attr_scaling_available_freqs,
 212         NULL,
 213 };
 214
 215 static struct cpufreq_driver bL_cpufreq_driver = {
 216         .name                   = "arm-big-little",
 217         .flags                  = CPUFREQ_STICKY,
 218         .verify                 = bL_cpufreq_verify_policy,
 219         .target                 = bL_cpufreq_set_target,
 220         .get                    = bL_cpufreq_get,
 221         .init                   = bL_cpufreq_init,
 222         .exit                   = bL_cpufreq_exit,
 223         .have_governor_per_policy = true,
 224         .attr                   = bL_cpufreq_attr,
 225 };
 226
 227 int bL_cpufreq_register(struct cpufreq_arm_bL_ops *ops)
 228 {
 229         int ret;
 230
 231         if (arm_bL_ops) {
 232                 pr_debug("%s: Already registered: %s, exiting\n", __func__,
 233                                 arm_bL_ops->name);
 234                 return -EBUSY;
 235         }
 236
 237         if (!ops || !strlen(ops->name) || !ops->init_opp_table) {
 238                 pr_err("%s: Invalid arm_bL_ops, exiting\n", __func__);
 239                 return -ENODEV;
 240         }
 241
 242         arm_bL_ops = ops;
 243
 244         ret = cpufreq_register_driver(&bL_cpufreq_driver);
 245         if (ret) {
 246                 pr_info("%s: Failed registering platform driver: %s, err: %d\n",
 247                                 __func__, ops->name, ret);
 248                 arm_bL_ops = NULL;
 249         } else {
 250                 pr_info("%s: Registered platform driver: %s\n", __func__,
 251                                 ops->name);
 252         }
 253
 254         return ret;
 255 }
 256 EXPORT_SYMBOL_GPL(bL_cpufreq_register);
 257
 258 void bL_cpufreq_unregister(struct cpufreq_arm_bL_ops *ops)
 259 {
 260         if (arm_bL_ops != ops) {
 261                 pr_err("%s: Registered with: %s, can't unregister, exiting\n",
 262                                 __func__, arm_bL_ops->name);
 263                 return;
 264         }
 265
 266         cpufreq_unregister_driver(&bL_cpufreq_driver);
 267         pr_info("%s: Un-registered platform driver: %s\n", __func__,
 268                         arm_bL_ops->name);
 269         arm_bL_ops = NULL;
 270 }
 271 EXPORT_SYMBOL_GPL(bL_cpufreq_unregister);