2 * ARM big.LITTLE Platforms CPUFreq support
4 * Copyright (C) 2013 ARM Ltd.
5 * Sudeep KarkadaNagesha <sudeep.karkadanagesha@arm.com>
7 * Copyright (C) 2013 Linaro.
8 * Viresh Kumar <viresh.kumar@linaro.org>
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.
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.
20 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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>
33 #include "arm_big_little.h"
35 /* Currently we support only two clusters */
36 #define MAX_CLUSTERS 2
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)};
43 static unsigned int bL_cpufreq_get(unsigned int cpu)
45 u32 cur_cluster = cpu_to_cluster(cpu);
47 return clk_get_rate(clk[cur_cluster]) / 1000;
50 /* Set clock frequency */
51 static int bL_cpufreq_set_target(struct cpufreq_policy *policy,
54 struct cpufreq_freqs freqs;
55 u32 cpu = policy->cpu, cur_cluster;
58 cur_cluster = cpu_to_cluster(policy->cpu);
60 freqs.old = bL_cpufreq_get(policy->cpu);
61 freqs.new = freq_table[cur_cluster][index].frequency;
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,
67 cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);
69 ret = clk_set_rate(clk[cur_cluster], freqs.new * 1000);
71 pr_err("clk_set_rate failed: %d\n", ret);
72 freqs.new = freqs.old;
75 cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);
80 static void put_cluster_clk_and_freq_table(struct device *cpu_dev)
82 u32 cluster = cpu_to_cluster(cpu_dev->id);
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);
91 static int get_cluster_clk_and_freq_table(struct device *cpu_dev)
93 u32 cluster = cpu_to_cluster(cpu_dev->id);
94 char name[14] = "cpu-cluster.";
97 if (atomic_inc_return(&cluster_usage[cluster]) != 1)
100 ret = arm_bL_ops->init_opp_table(cpu_dev);
102 dev_err(cpu_dev, "%s: init_opp_table failed, cpu: %d, err: %d\n",
103 __func__, cpu_dev->id, ret);
107 ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table[cluster]);
109 dev_err(cpu_dev, "%s: failed to init cpufreq table, cpu: %d, err: %d\n",
110 __func__, cpu_dev->id, ret);
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],
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]);
129 atomic_dec(&cluster_usage[cluster]);
130 dev_err(cpu_dev, "%s: Failed to get data for cluster: %d\n", __func__,
135 /* Per-CPU initialization */
136 static int bL_cpufreq_init(struct cpufreq_policy *policy)
138 u32 cur_cluster = cpu_to_cluster(policy->cpu);
139 struct device *cpu_dev;
142 cpu_dev = get_cpu_device(policy->cpu);
144 pr_err("%s: failed to get cpu%d device\n", __func__,
149 ret = get_cluster_clk_and_freq_table(cpu_dev);
153 ret = cpufreq_table_validate_and_show(policy, freq_table[cur_cluster]);
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);
161 if (arm_bL_ops->get_transition_latency)
162 policy->cpuinfo.transition_latency =
163 arm_bL_ops->get_transition_latency(cpu_dev);
165 policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
167 cpumask_copy(policy->cpus, topology_core_cpumask(policy->cpu));
169 dev_info(cpu_dev, "%s: CPU %d initialized\n", __func__, policy->cpu);
173 static int bL_cpufreq_exit(struct cpufreq_policy *policy)
175 struct device *cpu_dev;
177 cpu_dev = get_cpu_device(policy->cpu);
179 pr_err("%s: failed to get cpu%d device\n", __func__,
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);
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,
203 int bL_cpufreq_register(struct cpufreq_arm_bL_ops *ops)
208 pr_debug("%s: Already registered: %s, exiting\n", __func__,
213 if (!ops || !strlen(ops->name) || !ops->init_opp_table) {
214 pr_err("%s: Invalid arm_bL_ops, exiting\n", __func__);
220 ret = cpufreq_register_driver(&bL_cpufreq_driver);
222 pr_info("%s: Failed registering platform driver: %s, err: %d\n",
223 __func__, ops->name, ret);
226 pr_info("%s: Registered platform driver: %s\n", __func__,
232 EXPORT_SYMBOL_GPL(bL_cpufreq_register);
234 void bL_cpufreq_unregister(struct cpufreq_arm_bL_ops *ops)
236 if (arm_bL_ops != ops) {
237 pr_err("%s: Registered with: %s, can't unregister, exiting\n",
238 __func__, arm_bL_ops->name);
242 cpufreq_unregister_driver(&bL_cpufreq_driver);
243 pr_info("%s: Un-registered platform driver: %s\n", __func__,
247 EXPORT_SYMBOL_GPL(bL_cpufreq_unregister);