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 target_freq, unsigned int relation)
  53 {
  54         struct cpufreq_freqs freqs;
  55         u32 cpu = policy->cpu, freq_tab_idx, 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
  62         /* Determine valid target frequency using freq_table */
  63         cpufreq_frequency_table_target(policy, freq_table[cur_cluster],
  64                         target_freq, relation, &freq_tab_idx);
  65         freqs.new = freq_table[cur_cluster][freq_tab_idx].frequency;
  66
  67         pr_debug("%s: cpu: %d, cluster: %d, oldfreq: %d, target freq: %d, new freq: %d\n",
  68                         __func__, cpu, cur_cluster, freqs.old, target_freq,
  69                         freqs.new);
  70
  71         if (freqs.old == freqs.new)
  72                 return 0;
  73
  74         cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);
  75
  76         ret = clk_set_rate(clk[cur_cluster], freqs.new * 1000);
  77         if (ret) {
  78                 pr_err("clk_set_rate failed: %d\n", ret);
  79                 freqs.new = freqs.old;
  80         }
  81
  82         cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);
  83
  84         return ret;
  85 }
  86
  87 static void put_cluster_clk_and_freq_table(struct device *cpu_dev)
  88 {
  89         u32 cluster = cpu_to_cluster(cpu_dev->id);
  90
  91         if (!atomic_dec_return(&cluster_usage[cluster])) {
  92                 clk_put(clk[cluster]);
  93                 dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table[cluster]);
  94                 dev_dbg(cpu_dev, "%s: cluster: %d\n", __func__, cluster);
  95         }
  96 }
  97
  98 static int get_cluster_clk_and_freq_table(struct device *cpu_dev)
  99 {
 100         u32 cluster = cpu_to_cluster(cpu_dev->id);
 101         char name[14] = "cpu-cluster.";
 102         int ret;
 103
 104         if (atomic_inc_return(&cluster_usage[cluster]) != 1)
 105                 return 0;
 106
 107         ret = arm_bL_ops->init_opp_table(cpu_dev);
 108         if (ret) {
 109                 dev_err(cpu_dev, "%s: init_opp_table failed, cpu: %d, err: %d\n",
 110                                 __func__, cpu_dev->id, ret);
 111                 goto atomic_dec;
 112         }
 113
 114         ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table[cluster]);
 115         if (ret) {
 116                 dev_err(cpu_dev, "%s: failed to init cpufreq table, cpu: %d, err: %d\n",
 117                                 __func__, cpu_dev->id, ret);
 118                 goto atomic_dec;
 119         }
 120
 121         name[12] = cluster + '0';
 122         clk[cluster] = clk_get(cpu_dev, name);
 123         if (!IS_ERR(clk[cluster])) {
 124                 dev_dbg(cpu_dev, "%s: clk: %p & freq table: %p, cluster: %d\n",
 125                                 __func__, clk[cluster], freq_table[cluster],
 126                                 cluster);
 127                 return 0;
 128         }
 129
 130         dev_err(cpu_dev, "%s: Failed to get clk for cpu: %d, cluster: %d\n",
 131                         __func__, cpu_dev->id, cluster);
 132         ret = PTR_ERR(clk[cluster]);
 133         dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table[cluster]);
 134
 135 atomic_dec:
 136         atomic_dec(&cluster_usage[cluster]);
 137         dev_err(cpu_dev, "%s: Failed to get data for cluster: %d\n", __func__,
 138                         cluster);
 139         return ret;
 140 }
 141
 142 /* Per-CPU initialization */
 143 static int bL_cpufreq_init(struct cpufreq_policy *policy)
 144 {
 145         u32 cur_cluster = cpu_to_cluster(policy->cpu);
 146         struct device *cpu_dev;
 147         int ret;
 148
 149         cpu_dev = get_cpu_device(policy->cpu);
 150         if (!cpu_dev) {
 151                 pr_err("%s: failed to get cpu%d device\n", __func__,
 152                                 policy->cpu);
 153                 return -ENODEV;
 154         }
 155
 156         ret = get_cluster_clk_and_freq_table(cpu_dev);
 157         if (ret)
 158                 return ret;
 159
 160         ret = cpufreq_table_validate_and_show(policy, freq_table[cur_cluster]);
 161         if (ret) {
 162                 dev_err(cpu_dev, "CPU %d, cluster: %d invalid freq table\n",
 163                                 policy->cpu, cur_cluster);
 164                 put_cluster_clk_and_freq_table(cpu_dev);
 165                 return ret;
 166         }
 167
 168         if (arm_bL_ops->get_transition_latency)
 169                 policy->cpuinfo.transition_latency =
 170                         arm_bL_ops->get_transition_latency(cpu_dev);
 171         else
 172                 policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
 173
 174         cpumask_copy(policy->cpus, topology_core_cpumask(policy->cpu));
 175
 176         dev_info(cpu_dev, "%s: CPU %d initialized\n", __func__, policy->cpu);
 177         return 0;
 178 }
 179
 180 static int bL_cpufreq_exit(struct cpufreq_policy *policy)
 181 {
 182         struct device *cpu_dev;
 183
 184         cpu_dev = get_cpu_device(policy->cpu);
 185         if (!cpu_dev) {
 186                 pr_err("%s: failed to get cpu%d device\n", __func__,
 187                                 policy->cpu);
 188                 return -ENODEV;
 189         }
 190
 191         cpufreq_frequency_table_put_attr(policy->cpu);
 192         put_cluster_clk_and_freq_table(cpu_dev);
 193         dev_dbg(cpu_dev, "%s: Exited, cpu: %d\n", __func__, policy->cpu);
 194
 195         return 0;
 196 }
 197
 198 static struct cpufreq_driver bL_cpufreq_driver = {
 199         .name                   = "arm-big-little",
 200         .flags                  = CPUFREQ_STICKY |
 201                                         CPUFREQ_HAVE_GOVERNOR_PER_POLICY,
 202         .verify                 = cpufreq_generic_frequency_table_verify,
 203         .target                 = bL_cpufreq_set_target,
 204         .get                    = bL_cpufreq_get,
 205         .init                   = bL_cpufreq_init,
 206         .exit                   = bL_cpufreq_exit,
 207         .attr                   = cpufreq_generic_attr,
 208 };
 209
 210 int bL_cpufreq_register(struct cpufreq_arm_bL_ops *ops)
 211 {
 212         int ret;
 213
 214         if (arm_bL_ops) {
 215                 pr_debug("%s: Already registered: %s, exiting\n", __func__,
 216                                 arm_bL_ops->name);
 217                 return -EBUSY;
 218         }
 219
 220         if (!ops || !strlen(ops->name) || !ops->init_opp_table) {
 221                 pr_err("%s: Invalid arm_bL_ops, exiting\n", __func__);
 222                 return -ENODEV;
 223         }
 224
 225         arm_bL_ops = ops;
 226
 227         ret = cpufreq_register_driver(&bL_cpufreq_driver);
 228         if (ret) {
 229                 pr_info("%s: Failed registering platform driver: %s, err: %d\n",
 230                                 __func__, ops->name, ret);
 231                 arm_bL_ops = NULL;
 232         } else {
 233                 pr_info("%s: Registered platform driver: %s\n", __func__,
 234                                 ops->name);
 235         }
 236
 237         return ret;
 238 }
 239 EXPORT_SYMBOL_GPL(bL_cpufreq_register);
 240
 241 void bL_cpufreq_unregister(struct cpufreq_arm_bL_ops *ops)
 242 {
 243         if (arm_bL_ops != ops) {
 244                 pr_err("%s: Registered with: %s, can't unregister, exiting\n",
 245                                 __func__, arm_bL_ops->name);
 246                 return;
 247         }
 248
 249         cpufreq_unregister_driver(&bL_cpufreq_driver);
 250         pr_info("%s: Un-registered platform driver: %s\n", __func__,
 251                         arm_bL_ops->name);
 252         arm_bL_ops = NULL;
 253 }
 254 EXPORT_SYMBOL_GPL(bL_cpufreq_unregister);