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/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 int cpu_to_cluster(int cpu)
45 return topology_physical_package_id(cpu);
48 static unsigned int bL_cpufreq_get(unsigned int cpu)
50 u32 cur_cluster = cpu_to_cluster(cpu);
52 return clk_get_rate(clk[cur_cluster]) / 1000;
55 /* Validate policy frequency range */
56 static int bL_cpufreq_verify_policy(struct cpufreq_policy *policy)
58 u32 cur_cluster = cpu_to_cluster(policy->cpu);
60 return cpufreq_frequency_table_verify(policy, freq_table[cur_cluster]);
63 /* Set clock frequency */
64 static int bL_cpufreq_set_target(struct cpufreq_policy *policy,
65 unsigned int target_freq, unsigned int relation)
67 struct cpufreq_freqs freqs;
68 u32 cpu = policy->cpu, freq_tab_idx, cur_cluster;
71 cur_cluster = cpu_to_cluster(policy->cpu);
73 freqs.old = bL_cpufreq_get(policy->cpu);
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;
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,
84 if (freqs.old == freqs.new)
87 cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);
89 ret = clk_set_rate(clk[cur_cluster], freqs.new * 1000);
91 pr_err("clk_set_rate failed: %d\n", ret);
95 policy->cur = freqs.new;
97 cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);
102 static void put_cluster_clk_and_freq_table(struct device *cpu_dev)
104 u32 cluster = cpu_to_cluster(cpu_dev->id);
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);
113 static int get_cluster_clk_and_freq_table(struct device *cpu_dev)
115 u32 cluster = cpu_to_cluster(cpu_dev->id);
116 char name[14] = "cpu-cluster.";
119 if (atomic_inc_return(&cluster_usage[cluster]) != 1)
122 ret = arm_bL_ops->init_opp_table(cpu_dev);
124 dev_err(cpu_dev, "%s: init_opp_table failed, cpu: %d, err: %d\n",
125 __func__, cpu_dev->id, ret);
129 ret = opp_init_cpufreq_table(cpu_dev, &freq_table[cluster]);
131 dev_err(cpu_dev, "%s: failed to init cpufreq table, cpu: %d, err: %d\n",
132 __func__, cpu_dev->id, ret);
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],
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]);
151 atomic_dec(&cluster_usage[cluster]);
152 dev_err(cpu_dev, "%s: Failed to get data for cluster: %d\n", __func__,
157 /* Per-CPU initialization */
158 static int bL_cpufreq_init(struct cpufreq_policy *policy)
160 u32 cur_cluster = cpu_to_cluster(policy->cpu);
161 struct device *cpu_dev;
164 cpu_dev = get_cpu_device(policy->cpu);
166 pr_err("%s: failed to get cpu%d device\n", __func__,
171 ret = get_cluster_clk_and_freq_table(cpu_dev);
175 ret = cpufreq_frequency_table_cpuinfo(policy, freq_table[cur_cluster]);
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);
183 cpufreq_frequency_table_get_attr(freq_table[cur_cluster], policy->cpu);
185 if (arm_bL_ops->get_transition_latency)
186 policy->cpuinfo.transition_latency =
187 arm_bL_ops->get_transition_latency(cpu_dev);
189 policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
191 policy->cur = bL_cpufreq_get(policy->cpu);
193 cpumask_copy(policy->cpus, topology_core_cpumask(policy->cpu));
195 dev_info(cpu_dev, "CPU %d initialized\n", policy->cpu);
199 static int bL_cpufreq_exit(struct cpufreq_policy *policy)
201 struct device *cpu_dev;
203 cpu_dev = get_cpu_device(policy->cpu);
205 pr_err("%s: failed to get cpu%d device\n", __func__,
210 put_cluster_clk_and_freq_table(cpu_dev);
211 dev_dbg(cpu_dev, "%s: Exited, cpu: %d\n", __func__, policy->cpu);
216 /* Export freq_table to sysfs */
217 static struct freq_attr *bL_cpufreq_attr[] = {
218 &cpufreq_freq_attr_scaling_available_freqs,
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,
234 int bL_cpufreq_register(struct cpufreq_arm_bL_ops *ops)
239 pr_debug("%s: Already registered: %s, exiting\n", __func__,
244 if (!ops || !strlen(ops->name) || !ops->init_opp_table) {
245 pr_err("%s: Invalid arm_bL_ops, exiting\n", __func__);
251 ret = cpufreq_register_driver(&bL_cpufreq_driver);
253 pr_info("%s: Failed registering platform driver: %s, err: %d\n",
254 __func__, ops->name, ret);
257 pr_info("%s: Registered platform driver: %s\n", __func__,
263 EXPORT_SYMBOL_GPL(bL_cpufreq_register);
265 void bL_cpufreq_unregister(struct cpufreq_arm_bL_ops *ops)
267 if (arm_bL_ops != ops) {
268 pr_err("%s: Registered with: %s, can't unregister, exiting\n",
269 __func__, arm_bL_ops->name);
273 cpufreq_unregister_driver(&bL_cpufreq_driver);
274 pr_info("%s: Un-registered platform driver: %s\n", __func__,
278 EXPORT_SYMBOL_GPL(bL_cpufreq_unregister);