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/pm_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 /* Set clock frequency */
  51 static int bL_cpufreq_set_target(struct cpufreq_policy *policy,
  52                 unsigned int index)
  53 {
  54         struct cpufreq_freqs freqs;
  55         u32 cpu = policy->cpu, cur_cluster;
  56         int ret = 0;
  57
  58         cur_cluster = cpu_to_cluster(policy->cpu);
  59
  60         freqs.old = bL_cpufreq_get(policy->cpu);
  61         freqs.new = freq_table[cur_cluster][index].frequency;
  62
  63         pr_debug("%s: cpu: %d, cluster: %d, oldfreq: %d, target freq: %d, new freq: %d\n",
  64                         __func__, cpu, cur_cluster, freqs.old, freqs.new,
  65                         freqs.new);
  66
  67         cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);
  68
  69         ret = clk_set_rate(clk[cur_cluster], freqs.new * 1000);
  70         if (ret) {
  71                 pr_err("clk_set_rate failed: %d\n", ret);
  72                 freqs.new = freqs.old;
  73         }
  74
  75         cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);
  76
  77         return ret;
  78 }
  79
  80 static void put_cluster_clk_and_freq_table(struct device *cpu_dev)
  81 {
  82         u32 cluster = cpu_to_cluster(cpu_dev->id);
  83
  84         if (!atomic_dec_return(&cluster_usage[cluster])) {
  85                 clk_put(clk[cluster]);
  86                 dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table[cluster]);
  87                 dev_dbg(cpu_dev, "%s: cluster: %d\n", __func__, cluster);
  88         }
  89 }
  90
  91 static int get_cluster_clk_and_freq_table(struct device *cpu_dev)
  92 {
  93         u32 cluster = cpu_to_cluster(cpu_dev->id);
  94         char name[14] = "cpu-cluster.";
  95         int ret;
  96
  97         if (atomic_inc_return(&cluster_usage[cluster]) != 1)
  98                 return 0;
  99
 100         ret = arm_bL_ops->init_opp_table(cpu_dev);
 101         if (ret) {
 102                 dev_err(cpu_dev, "%s: init_opp_table failed, cpu: %d, err: %d\n",
 103                                 __func__, cpu_dev->id, ret);
 104                 goto atomic_dec;
 105         }
 106
 107         ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table[cluster]);
 108         if (ret) {
 109                 dev_err(cpu_dev, "%s: failed to init cpufreq table, cpu: %d, err: %d\n",
 110                                 __func__, cpu_dev->id, ret);
 111                 goto atomic_dec;
 112         }
 113
 114         name[12] = cluster + '0';
 115         clk[cluster] = clk_get(cpu_dev, name);
 116         if (!IS_ERR(clk[cluster])) {
 117                 dev_dbg(cpu_dev, "%s: clk: %p & freq table: %p, cluster: %d\n",
 118                                 __func__, clk[cluster], freq_table[cluster],
 119                                 cluster);
 120                 return 0;
 121         }
 122
 123         dev_err(cpu_dev, "%s: Failed to get clk for cpu: %d, cluster: %d\n",
 124                         __func__, cpu_dev->id, cluster);
 125         ret = PTR_ERR(clk[cluster]);
 126         dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table[cluster]);
 127
 128 atomic_dec:
 129         atomic_dec(&cluster_usage[cluster]);
 130         dev_err(cpu_dev, "%s: Failed to get data for cluster: %d\n", __func__,
 131                         cluster);
 132         return ret;
 133 }
 134
 135 /* Per-CPU initialization */
 136 static int bL_cpufreq_init(struct cpufreq_policy *policy)
 137 {
 138         u32 cur_cluster = cpu_to_cluster(policy->cpu);
 139         struct device *cpu_dev;
 140         int ret;
 141
 142         cpu_dev = get_cpu_device(policy->cpu);
 143         if (!cpu_dev) {
 144                 pr_err("%s: failed to get cpu%d device\n", __func__,
 145                                 policy->cpu);
 146                 return -ENODEV;
 147         }
 148
 149         ret = get_cluster_clk_and_freq_table(cpu_dev);
 150         if (ret)
 151                 return ret;
 152
 153         ret = cpufreq_table_validate_and_show(policy, freq_table[cur_cluster]);
 154         if (ret) {
 155                 dev_err(cpu_dev, "CPU %d, cluster: %d invalid freq table\n",
 156                                 policy->cpu, cur_cluster);
 157                 put_cluster_clk_and_freq_table(cpu_dev);
 158                 return ret;
 159         }
 160
 161         if (arm_bL_ops->get_transition_latency)
 162                 policy->cpuinfo.transition_latency =
 163                         arm_bL_ops->get_transition_latency(cpu_dev);
 164         else
 165                 policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
 166
 167         cpumask_copy(policy->cpus, topology_core_cpumask(policy->cpu));
 168
 169         dev_info(cpu_dev, "%s: CPU %d initialized\n", __func__, policy->cpu);
 170         return 0;
 171 }
 172
 173 static int bL_cpufreq_exit(struct cpufreq_policy *policy)
 174 {
 175         struct device *cpu_dev;
 176
 177         cpu_dev = get_cpu_device(policy->cpu);
 178         if (!cpu_dev) {
 179                 pr_err("%s: failed to get cpu%d device\n", __func__,
 180                                 policy->cpu);
 181                 return -ENODEV;
 182         }
 183
 184         cpufreq_frequency_table_put_attr(policy->cpu);
 185         put_cluster_clk_and_freq_table(cpu_dev);
 186         dev_dbg(cpu_dev, "%s: Exited, cpu: %d\n", __func__, policy->cpu);
 187
 188         return 0;
 189 }
 190
 191 static struct cpufreq_driver bL_cpufreq_driver = {
 192         .name                   = "arm-big-little",
 193         .flags                  = CPUFREQ_STICKY |
 194                                         CPUFREQ_HAVE_GOVERNOR_PER_POLICY,
 195         .verify                 = cpufreq_generic_frequency_table_verify,
 196         .target_index           = bL_cpufreq_set_target,
 197         .get                    = bL_cpufreq_get,
 198         .init                   = bL_cpufreq_init,
 199         .exit                   = bL_cpufreq_exit,
 200         .attr                   = cpufreq_generic_attr,
 201 };
 202
 203 int bL_cpufreq_register(struct cpufreq_arm_bL_ops *ops)
 204 {
 205         int ret;
 206
 207         if (arm_bL_ops) {
 208                 pr_debug("%s: Already registered: %s, exiting\n", __func__,
 209                                 arm_bL_ops->name);
 210                 return -EBUSY;
 211         }
 212
 213         if (!ops || !strlen(ops->name) || !ops->init_opp_table) {
 214                 pr_err("%s: Invalid arm_bL_ops, exiting\n", __func__);
 215                 return -ENODEV;
 216         }
 217
 218         arm_bL_ops = ops;
 219
 220         ret = cpufreq_register_driver(&bL_cpufreq_driver);
 221         if (ret) {
 222                 pr_info("%s: Failed registering platform driver: %s, err: %d\n",
 223                                 __func__, ops->name, ret);
 224                 arm_bL_ops = NULL;
 225         } else {
 226                 pr_info("%s: Registered platform driver: %s\n", __func__,
 227                                 ops->name);
 228         }
 229
 230         return ret;
 231 }
 232 EXPORT_SYMBOL_GPL(bL_cpufreq_register);
 233
 234 void bL_cpufreq_unregister(struct cpufreq_arm_bL_ops *ops)
 235 {
 236         if (arm_bL_ops != ops) {
 237                 pr_err("%s: Registered with: %s, can't unregister, exiting\n",
 238                                 __func__, arm_bL_ops->name);
 239                 return;
 240         }
 241
 242         cpufreq_unregister_driver(&bL_cpufreq_driver);
 243         pr_info("%s: Un-registered platform driver: %s\n", __func__,
 244                         arm_bL_ops->name);
 245         arm_bL_ops = NULL;
 246 }
 247 EXPORT_SYMBOL_GPL(bL_cpufreq_unregister);