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 int cpu_to_cluster(int cpu)
  44 {
  45         return topology_physical_package_id(cpu);
  46 }
  47
  48 static unsigned int bL_cpufreq_get(unsigned int cpu)
  49 {
  50         u32 cur_cluster = cpu_to_cluster(cpu);
  51
  52         return clk_get_rate(clk[cur_cluster]) / 1000;
  53 }
  54
  55 /* Validate policy frequency range */
  56 static int bL_cpufreq_verify_policy(struct cpufreq_policy *policy)
  57 {
  58         u32 cur_cluster = cpu_to_cluster(policy->cpu);
  59
  60         return cpufreq_frequency_table_verify(policy, freq_table[cur_cluster]);
  61 }
  62
  63 /* Set clock frequency */
  64 static int bL_cpufreq_set_target(struct cpufreq_policy *policy,
  65                 unsigned int target_freq, unsigned int relation)
  66 {
  67         struct cpufreq_freqs freqs;
  68         u32 cpu = policy->cpu, freq_tab_idx, cur_cluster;
  69         int ret = 0;
  70
  71         cur_cluster = cpu_to_cluster(policy->cpu);
  72
  73         freqs.old = bL_cpufreq_get(policy->cpu);
  74
  75         /* Determine valid target frequency using freq_table */
  76         cpufreq_frequency_table_target(policy, freq_table[cur_cluster],
  77                         target_freq, relation, &freq_tab_idx);
  78         freqs.new = freq_table[cur_cluster][freq_tab_idx].frequency;
  79
  80         pr_debug("%s: cpu: %d, cluster: %d, oldfreq: %d, target freq: %d, new freq: %d\n",
  81                         __func__, cpu, cur_cluster, freqs.old, target_freq,
  82                         freqs.new);
  83
  84         if (freqs.old == freqs.new)
  85                 return 0;
  86
  87         cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);
  88
  89         ret = clk_set_rate(clk[cur_cluster], freqs.new * 1000);
  90         if (ret) {
  91                 pr_err("clk_set_rate failed: %d\n", ret);
  92                 return ret;
  93         }
  94
  95         policy->cur = freqs.new;
  96
  97         cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);
  98
  99         return ret;
 100 }
 101
 102 static void put_cluster_clk_and_freq_table(struct device *cpu_dev)
 103 {
 104         u32 cluster = cpu_to_cluster(cpu_dev->id);
 105
 106         if (!atomic_dec_return(&cluster_usage[cluster])) {
 107                 clk_put(clk[cluster]);
 108                 opp_free_cpufreq_table(cpu_dev, &freq_table[cluster]);
 109                 dev_dbg(cpu_dev, "%s: cluster: %d\n", __func__, cluster);
 110         }
 111 }
 112
 113 static int get_cluster_clk_and_freq_table(struct device *cpu_dev)
 114 {
 115         u32 cluster = cpu_to_cluster(cpu_dev->id);
 116         char name[14] = "cpu-cluster.";
 117         int ret;
 118
 119         if (atomic_inc_return(&cluster_usage[cluster]) != 1)
 120                 return 0;
 121
 122         ret = arm_bL_ops->init_opp_table(cpu_dev);
 123         if (ret) {
 124                 dev_err(cpu_dev, "%s: init_opp_table failed, cpu: %d, err: %d\n",
 125                                 __func__, cpu_dev->id, ret);
 126                 goto atomic_dec;
 127         }
 128
 129         ret = opp_init_cpufreq_table(cpu_dev, &freq_table[cluster]);
 130         if (ret) {
 131                 dev_err(cpu_dev, "%s: failed to init cpufreq table, cpu: %d, err: %d\n",
 132                                 __func__, cpu_dev->id, ret);
 133                 goto atomic_dec;
 134         }
 135
 136         name[12] = cluster + '0';
 137         clk[cluster] = clk_get_sys(name, NULL);
 138         if (!IS_ERR(clk[cluster])) {
 139                 dev_dbg(cpu_dev, "%s: clk: %p & freq table: %p, cluster: %d\n",
 140                                 __func__, clk[cluster], freq_table[cluster],
 141                                 cluster);
 142                 return 0;
 143         }
 144
 145         dev_err(cpu_dev, "%s: Failed to get clk for cpu: %d, cluster: %d\n",
 146                         __func__, cpu_dev->id, cluster);
 147         ret = PTR_ERR(clk[cluster]);
 148         opp_free_cpufreq_table(cpu_dev, &freq_table[cluster]);
 149
 150 atomic_dec:
 151         atomic_dec(&cluster_usage[cluster]);
 152         dev_err(cpu_dev, "%s: Failed to get data for cluster: %d\n", __func__,
 153                         cluster);
 154         return ret;
 155 }
 156
 157 /* Per-CPU initialization */
 158 static int bL_cpufreq_init(struct cpufreq_policy *policy)
 159 {
 160         u32 cur_cluster = cpu_to_cluster(policy->cpu);
 161         struct device *cpu_dev;
 162         int ret;
 163
 164         cpu_dev = get_cpu_device(policy->cpu);
 165         if (!cpu_dev) {
 166                 pr_err("%s: failed to get cpu%d device\n", __func__,
 167                                 policy->cpu);
 168                 return -ENODEV;
 169         }
 170
 171         ret = get_cluster_clk_and_freq_table(cpu_dev);
 172         if (ret)
 173                 return ret;
 174
 175         ret = cpufreq_frequency_table_cpuinfo(policy, freq_table[cur_cluster]);
 176         if (ret) {
 177                 dev_err(cpu_dev, "CPU %d, cluster: %d invalid freq table\n",
 178                                 policy->cpu, cur_cluster);
 179                 put_cluster_clk_and_freq_table(cpu_dev);
 180                 return ret;
 181         }
 182
 183         cpufreq_frequency_table_get_attr(freq_table[cur_cluster], policy->cpu);
 184
 185         if (arm_bL_ops->get_transition_latency)
 186                 policy->cpuinfo.transition_latency =
 187                         arm_bL_ops->get_transition_latency(cpu_dev);
 188         else
 189                 policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
 190
 191         policy->cur = bL_cpufreq_get(policy->cpu);
 192
 193         cpumask_copy(policy->cpus, topology_core_cpumask(policy->cpu));
 194
 195         dev_info(cpu_dev, "CPU %d initialized\n", policy->cpu);
 196         return 0;
 197 }
 198
 199 static int bL_cpufreq_exit(struct cpufreq_policy *policy)
 200 {
 201         struct device *cpu_dev;
 202
 203         cpu_dev = get_cpu_device(policy->cpu);
 204         if (!cpu_dev) {
 205                 pr_err("%s: failed to get cpu%d device\n", __func__,
 206                                 policy->cpu);
 207                 return -ENODEV;
 208         }
 209
 210         put_cluster_clk_and_freq_table(cpu_dev);
 211         dev_dbg(cpu_dev, "%s: Exited, cpu: %d\n", __func__, policy->cpu);
 212
 213         return 0;
 214 }
 215
 216 /* Export freq_table to sysfs */
 217 static struct freq_attr *bL_cpufreq_attr[] = {
 218         &cpufreq_freq_attr_scaling_available_freqs,
 219         NULL,
 220 };
 221
 222 static struct cpufreq_driver bL_cpufreq_driver = {
 223         .name                   = "arm-big-little",
 224         .flags                  = CPUFREQ_STICKY,
 225         .verify                 = bL_cpufreq_verify_policy,
 226         .target                 = bL_cpufreq_set_target,
 227         .get                    = bL_cpufreq_get,
 228         .init                   = bL_cpufreq_init,
 229         .exit                   = bL_cpufreq_exit,
 230         .have_governor_per_policy = true,
 231         .attr                   = bL_cpufreq_attr,
 232 };
 233
 234 int bL_cpufreq_register(struct cpufreq_arm_bL_ops *ops)
 235 {
 236         int ret;
 237
 238         if (arm_bL_ops) {
 239                 pr_debug("%s: Already registered: %s, exiting\n", __func__,
 240                                 arm_bL_ops->name);
 241                 return -EBUSY;
 242         }
 243
 244         if (!ops || !strlen(ops->name) || !ops->init_opp_table) {
 245                 pr_err("%s: Invalid arm_bL_ops, exiting\n", __func__);
 246                 return -ENODEV;
 247         }
 248
 249         arm_bL_ops = ops;
 250
 251         ret = cpufreq_register_driver(&bL_cpufreq_driver);
 252         if (ret) {
 253                 pr_info("%s: Failed registering platform driver: %s, err: %d\n",
 254                                 __func__, ops->name, ret);
 255                 arm_bL_ops = NULL;
 256         } else {
 257                 pr_info("%s: Registered platform driver: %s\n", __func__,
 258                                 ops->name);
 259         }
 260
 261         return ret;
 262 }
 263 EXPORT_SYMBOL_GPL(bL_cpufreq_register);
 264
 265 void bL_cpufreq_unregister(struct cpufreq_arm_bL_ops *ops)
 266 {
 267         if (arm_bL_ops != ops) {
 268                 pr_err("%s: Registered with: %s, can't unregister, exiting\n",
 269                                 __func__, arm_bL_ops->name);
 270                 return;
 271         }
 272
 273         cpufreq_unregister_driver(&bL_cpufreq_driver);
 274         pr_info("%s: Un-registered platform driver: %s\n", __func__,
 275                         arm_bL_ops->name);
 276         arm_bL_ops = NULL;
 277 }
 278 EXPORT_SYMBOL_GPL(bL_cpufreq_unregister);