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/mutex.h>
28 #include <linux/of_platform.h>
29 #include <linux/opp.h>
30 #include <linux/slab.h>
31 #include <linux/topology.h>
32 #include <linux/types.h>
33 #include <asm/bL_switcher.h>
35 #include "arm_big_little.h"
37 #ifdef CONFIG_BL_SWITCHER
38 bool bL_switching_enabled;
41 #define ACTUAL_FREQ(cluster, freq) ((cluster == A7_CLUSTER) ? freq << 1 : freq)
42 #define VIRT_FREQ(cluster, freq) ((cluster == A7_CLUSTER) ? freq >> 1 : freq)
44 static struct cpufreq_arm_bL_ops *arm_bL_ops;
45 static struct clk *clk[MAX_CLUSTERS];
46 static struct cpufreq_frequency_table *freq_table[MAX_CLUSTERS + 1];
47 static atomic_t cluster_usage[MAX_CLUSTERS + 1] = {ATOMIC_INIT(0),
50 static unsigned int clk_big_min; /* (Big) clock frequencies */
51 static unsigned int clk_little_max; /* Maximum clock frequency (Little) */
53 static DEFINE_PER_CPU(unsigned int, physical_cluster);
54 static DEFINE_PER_CPU(unsigned int, cpu_last_req_freq);
56 static struct mutex cluster_lock[MAX_CLUSTERS];
58 static unsigned int find_cluster_maxfreq(int cluster)
61 u32 max_freq = 0, cpu_freq;
63 for_each_online_cpu(j) {
64 cpu_freq = per_cpu(cpu_last_req_freq, j);
66 if ((cluster == per_cpu(physical_cluster, j)) &&
67 (max_freq < cpu_freq))
71 pr_debug("%s: cluster: %d, max freq: %d\n", __func__, cluster,
77 static unsigned int clk_get_cpu_rate(unsigned int cpu)
79 u32 cur_cluster = per_cpu(physical_cluster, cpu);
80 u32 rate = clk_get_rate(clk[cur_cluster]) / 1000;
82 /* For switcher we use virtual A15 clock rates */
83 if (is_bL_switching_enabled())
84 rate = VIRT_FREQ(cur_cluster, rate);
86 pr_debug("%s: cpu: %d, cluster: %d, freq: %u\n", __func__, cpu,
92 static unsigned int bL_cpufreq_get_rate(unsigned int cpu)
94 if (is_bL_switching_enabled()) {
95 pr_debug("%s: freq: %d\n", __func__, per_cpu(cpu_last_req_freq,
98 return per_cpu(cpu_last_req_freq, cpu);
100 return clk_get_cpu_rate(cpu);
105 bL_cpufreq_set_rate(u32 cpu, u32 old_cluster, u32 new_cluster, u32 rate)
107 u32 new_rate, prev_rate;
109 bool bLs = is_bL_switching_enabled();
111 mutex_lock(&cluster_lock[new_cluster]);
114 prev_rate = per_cpu(cpu_last_req_freq, cpu);
115 per_cpu(cpu_last_req_freq, cpu) = rate;
116 per_cpu(physical_cluster, cpu) = new_cluster;
118 new_rate = find_cluster_maxfreq(new_cluster);
119 new_rate = ACTUAL_FREQ(new_cluster, new_rate);
124 pr_debug("%s: cpu: %d, old cluster: %d, new cluster: %d, freq: %d\n",
125 __func__, cpu, old_cluster, new_cluster, new_rate);
127 ret = clk_set_rate(clk[new_cluster], new_rate * 1000);
129 pr_err("clk_set_rate failed: %d, new cluster: %d\n", ret,
132 per_cpu(cpu_last_req_freq, cpu) = prev_rate;
133 per_cpu(physical_cluster, cpu) = old_cluster;
136 mutex_unlock(&cluster_lock[new_cluster]);
141 mutex_unlock(&cluster_lock[new_cluster]);
143 /* Recalc freq for old cluster when switching clusters */
144 if (old_cluster != new_cluster) {
145 pr_debug("%s: cpu: %d, old cluster: %d, new cluster: %d\n",
146 __func__, cpu, old_cluster, new_cluster);
149 bL_switch_request(cpu, new_cluster);
151 mutex_lock(&cluster_lock[old_cluster]);
153 /* Set freq of old cluster if there are cpus left on it */
154 new_rate = find_cluster_maxfreq(old_cluster);
155 new_rate = ACTUAL_FREQ(old_cluster, new_rate);
158 pr_debug("%s: Updating rate of old cluster: %d, to freq: %d\n",
159 __func__, old_cluster, new_rate);
161 if (clk_set_rate(clk[old_cluster], new_rate * 1000))
162 pr_err("%s: clk_set_rate failed: %d, old cluster: %d\n",
163 __func__, ret, old_cluster);
165 mutex_unlock(&cluster_lock[old_cluster]);
171 /* Validate policy frequency range */
172 static int bL_cpufreq_verify_policy(struct cpufreq_policy *policy)
174 u32 cur_cluster = cpu_to_cluster(policy->cpu);
176 return cpufreq_frequency_table_verify(policy, freq_table[cur_cluster]);
179 /* Set clock frequency */
180 static int bL_cpufreq_set_target(struct cpufreq_policy *policy,
181 unsigned int target_freq, unsigned int relation)
183 struct cpufreq_freqs freqs;
184 u32 cpu = policy->cpu, freq_tab_idx, cur_cluster, new_cluster,
188 cur_cluster = cpu_to_cluster(cpu);
189 new_cluster = actual_cluster = per_cpu(physical_cluster, cpu);
191 freqs.old = bL_cpufreq_get_rate(cpu);
193 /* Determine valid target frequency using freq_table */
194 cpufreq_frequency_table_target(policy, freq_table[cur_cluster],
195 target_freq, relation, &freq_tab_idx);
196 freqs.new = freq_table[cur_cluster][freq_tab_idx].frequency;
198 pr_debug("%s: cpu: %d, cluster: %d, oldfreq: %d, target freq: %d, new freq: %d\n",
199 __func__, cpu, cur_cluster, freqs.old, target_freq,
202 if (freqs.old == freqs.new)
205 if (is_bL_switching_enabled()) {
206 if ((actual_cluster == A15_CLUSTER) &&
207 (freqs.new < clk_big_min)) {
208 new_cluster = A7_CLUSTER;
209 } else if ((actual_cluster == A7_CLUSTER) &&
210 (freqs.new > clk_little_max)) {
211 new_cluster = A15_CLUSTER;
215 cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);
217 ret = bL_cpufreq_set_rate(cpu, actual_cluster, new_cluster, freqs.new);
221 policy->cur = freqs.new;
223 cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);
228 static inline u32 get_table_count(struct cpufreq_frequency_table *table)
232 for (count = 0; table[count].frequency != CPUFREQ_TABLE_END; count++)
238 /* get the minimum frequency in the cpufreq_frequency_table */
239 static inline u32 get_table_min(struct cpufreq_frequency_table *table)
242 uint32_t min_freq = ~0;
243 for (i = 0; (table[i].frequency != CPUFREQ_TABLE_END); i++)
244 if (table[i].frequency < min_freq)
245 min_freq = table[i].frequency;
249 /* get the maximum frequency in the cpufreq_frequency_table */
250 static inline u32 get_table_max(struct cpufreq_frequency_table *table)
253 uint32_t max_freq = 0;
254 for (i = 0; (table[i].frequency != CPUFREQ_TABLE_END); i++)
255 if (table[i].frequency > max_freq)
256 max_freq = table[i].frequency;
260 static int merge_cluster_tables(void)
262 int i, j, k = 0, count = 1;
263 struct cpufreq_frequency_table *table;
265 for (i = 0; i < MAX_CLUSTERS; i++)
266 count += get_table_count(freq_table[i]);
268 table = kzalloc(sizeof(*table) * count, GFP_KERNEL);
272 freq_table[MAX_CLUSTERS] = table;
274 /* Add in reverse order to get freqs in increasing order */
275 for (i = MAX_CLUSTERS - 1; i >= 0; i--) {
276 for (j = 0; freq_table[i][j].frequency != CPUFREQ_TABLE_END;
278 table[k].frequency = VIRT_FREQ(i,
279 freq_table[i][j].frequency);
280 pr_debug("%s: index: %d, freq: %d\n", __func__, k,
287 table[k].frequency = CPUFREQ_TABLE_END;
289 pr_debug("%s: End, table: %p, count: %d\n", __func__, table, k);
294 static void _put_cluster_clk_and_freq_table(struct device *cpu_dev)
296 u32 cluster = cpu_to_cluster(cpu_dev->id);
298 if (!atomic_dec_return(&cluster_usage[cluster])) {
299 clk_put(clk[cluster]);
300 opp_free_cpufreq_table(cpu_dev, &freq_table[cluster]);
301 dev_dbg(cpu_dev, "%s: cluster: %d\n", __func__, cluster);
305 static void put_cluster_clk_and_freq_table(struct device *cpu_dev)
307 u32 cluster = cpu_to_cluster(cpu_dev->id);
310 if (cluster < MAX_CLUSTERS)
311 return _put_cluster_clk_and_freq_table(cpu_dev);
313 if (atomic_dec_return(&cluster_usage[MAX_CLUSTERS]))
316 for (i = 0; i < MAX_CLUSTERS; i++) {
317 struct device *cdev = get_cpu_device(i);
319 pr_err("%s: failed to get cpu%d device\n", __func__, i);
323 _put_cluster_clk_and_freq_table(cdev);
326 /* free virtual table */
327 kfree(freq_table[MAX_CLUSTERS]);
330 static int _get_cluster_clk_and_freq_table(struct device *cpu_dev)
332 u32 cluster = cpu_to_cluster(cpu_dev->id);
333 char name[14] = "cpu-cluster.X";
336 if (atomic_inc_return(&cluster_usage[cluster]) != 1)
339 ret = arm_bL_ops->init_opp_table(cpu_dev);
341 dev_err(cpu_dev, "%s: init_opp_table failed, cpu: %d, err: %d\n",
342 __func__, cpu_dev->id, ret);
346 ret = opp_init_cpufreq_table(cpu_dev, &freq_table[cluster]);
348 dev_err(cpu_dev, "%s: failed to init cpufreq table, cpu: %d, err: %d\n",
349 __func__, cpu_dev->id, ret);
353 name[12] = cluster + '0';
354 clk[cluster] = clk_get_sys(name, NULL);
355 if (!IS_ERR(clk[cluster])) {
356 dev_dbg(cpu_dev, "%s: clk: %p & freq table: %p, cluster: %d\n",
357 __func__, clk[cluster], freq_table[cluster],
362 dev_err(cpu_dev, "%s: Failed to get clk for cpu: %d, cluster: %d\n",
363 __func__, cpu_dev->id, cluster);
364 ret = PTR_ERR(clk[cluster]);
365 opp_free_cpufreq_table(cpu_dev, &freq_table[cluster]);
368 atomic_dec(&cluster_usage[cluster]);
369 dev_err(cpu_dev, "%s: Failed to get data for cluster: %d\n", __func__,
374 static int get_cluster_clk_and_freq_table(struct device *cpu_dev)
376 u32 cluster = cpu_to_cluster(cpu_dev->id);
379 if (cluster < MAX_CLUSTERS)
380 return _get_cluster_clk_and_freq_table(cpu_dev);
382 if (atomic_inc_return(&cluster_usage[MAX_CLUSTERS]) != 1)
386 * Get data for all clusters and fill virtual cluster with a merge of
389 for (i = 0; i < MAX_CLUSTERS; i++) {
390 struct device *cdev = get_cpu_device(i);
392 pr_err("%s: failed to get cpu%d device\n", __func__, i);
396 ret = _get_cluster_clk_and_freq_table(cdev);
401 ret = merge_cluster_tables();
405 /* Assuming 2 cluster, set clk_big_min and clk_little_max */
406 clk_big_min = get_table_min(freq_table[0]);
407 clk_little_max = VIRT_FREQ(1, get_table_max(freq_table[1]));
409 pr_debug("%s: cluster: %d, clk_big_min: %d, clk_little_max: %d\n",
410 __func__, cluster, clk_big_min, clk_little_max);
416 struct device *cdev = get_cpu_device(i);
418 pr_err("%s: failed to get cpu%d device\n", __func__, i);
422 _put_cluster_clk_and_freq_table(cdev);
425 atomic_dec(&cluster_usage[MAX_CLUSTERS]);
430 /* Per-CPU initialization */
431 static int bL_cpufreq_init(struct cpufreq_policy *policy)
433 u32 cur_cluster = cpu_to_cluster(policy->cpu);
434 struct device *cpu_dev;
437 cpu_dev = get_cpu_device(policy->cpu);
439 pr_err("%s: failed to get cpu%d device\n", __func__,
444 ret = get_cluster_clk_and_freq_table(cpu_dev);
448 ret = cpufreq_frequency_table_cpuinfo(policy, freq_table[cur_cluster]);
450 dev_err(cpu_dev, "CPU %d, cluster: %d invalid freq table\n",
451 policy->cpu, cur_cluster);
452 put_cluster_clk_and_freq_table(cpu_dev);
456 cpufreq_frequency_table_get_attr(freq_table[cur_cluster], policy->cpu);
458 if (cur_cluster < MAX_CLUSTERS) {
461 cpumask_copy(policy->cpus, topology_core_cpumask(policy->cpu));
463 for_each_cpu(cpu, policy->cpus)
464 per_cpu(physical_cluster, cpu) = cur_cluster;
466 /* Assumption: during init, we are always running on A15 */
467 per_cpu(physical_cluster, policy->cpu) = A15_CLUSTER;
470 if (arm_bL_ops->get_transition_latency)
471 policy->cpuinfo.transition_latency =
472 arm_bL_ops->get_transition_latency(cpu_dev);
474 policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
476 policy->cur = clk_get_cpu_rate(policy->cpu);
478 if (is_bL_switching_enabled())
479 per_cpu(cpu_last_req_freq, policy->cpu) = policy->cur;
481 dev_info(cpu_dev, "%s: CPU %d initialized\n", __func__, policy->cpu);
485 /* Export freq_table to sysfs */
486 static struct freq_attr *bL_cpufreq_attr[] = {
487 &cpufreq_freq_attr_scaling_available_freqs,
491 static struct cpufreq_driver bL_cpufreq_driver = {
492 .name = "arm-big-little",
493 .flags = CPUFREQ_STICKY,
494 .verify = bL_cpufreq_verify_policy,
495 .target = bL_cpufreq_set_target,
496 .get = bL_cpufreq_get_rate,
497 .init = bL_cpufreq_init,
498 .have_governor_per_policy = true,
499 .attr = bL_cpufreq_attr,
502 static int bL_cpufreq_switcher_notifier(struct notifier_block *nfb,
503 unsigned long action, void *_arg)
505 pr_debug("%s: action: %ld\n", __func__, action);
508 case BL_NOTIFY_PRE_ENABLE:
509 case BL_NOTIFY_PRE_DISABLE:
510 cpufreq_unregister_driver(&bL_cpufreq_driver);
513 case BL_NOTIFY_POST_ENABLE:
514 set_switching_enabled(true);
515 cpufreq_register_driver(&bL_cpufreq_driver);
518 case BL_NOTIFY_POST_DISABLE:
519 set_switching_enabled(false);
520 cpufreq_register_driver(&bL_cpufreq_driver);
530 static struct notifier_block bL_switcher_notifier = {
531 .notifier_call = bL_cpufreq_switcher_notifier,
534 int bL_cpufreq_register(struct cpufreq_arm_bL_ops *ops)
539 pr_debug("%s: Already registered: %s, exiting\n", __func__,
544 if (!ops || !strlen(ops->name) || !ops->init_opp_table) {
545 pr_err("%s: Invalid arm_bL_ops, exiting\n", __func__);
551 ret = bL_switcher_get_enabled();
552 set_switching_enabled(ret);
554 for (i = 0; i < MAX_CLUSTERS; i++)
555 mutex_init(&cluster_lock[i]);
557 ret = cpufreq_register_driver(&bL_cpufreq_driver);
559 pr_info("%s: Failed registering platform driver: %s, err: %d\n",
560 __func__, ops->name, ret);
563 ret = bL_switcher_register_notifier(&bL_switcher_notifier);
565 cpufreq_unregister_driver(&bL_cpufreq_driver);
568 pr_info("%s: Registered platform driver: %s\n",
569 __func__, ops->name);
573 bL_switcher_put_enabled();
576 EXPORT_SYMBOL_GPL(bL_cpufreq_register);
578 void bL_cpufreq_unregister(struct cpufreq_arm_bL_ops *ops)
580 if (arm_bL_ops != ops) {
581 pr_err("%s: Registered with: %s, can't unregister, exiting\n",
582 __func__, arm_bL_ops->name);
586 bL_switcher_get_enabled();
587 bL_switcher_unregister_notifier(&bL_switcher_notifier);
588 cpufreq_unregister_driver(&bL_cpufreq_driver);
589 bL_switcher_put_enabled();
590 pr_info("%s: Un-registered platform driver: %s\n", __func__,
593 /* For saving table get/put on every cpu in/out */
594 if (is_bL_switching_enabled()) {
595 put_cluster_clk_and_freq_table(get_cpu_device(0));
599 for (i = 0; i < MAX_CLUSTERS; i++) {
600 struct device *cdev = get_cpu_device(i);
602 pr_err("%s: failed to get cpu%d device\n",
607 put_cluster_clk_and_freq_table(cdev);
613 EXPORT_SYMBOL_GPL(bL_cpufreq_unregister);