LiteX: driver for MMCM
[linux/fpc-iii.git] / drivers / cpufreq / vexpress-spc-cpufreq.c
blobf711d8eaea6a25793080a27f2de1b27f539f347e
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Versatile Express SPC CPUFreq Interface driver
5 * Copyright (C) 2013 - 2019 ARM Ltd.
6 * Sudeep Holla <sudeep.holla@arm.com>
8 * Copyright (C) 2013 Linaro.
9 * Viresh Kumar <viresh.kumar@linaro.org>
12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
14 #include <linux/clk.h>
15 #include <linux/cpu.h>
16 #include <linux/cpufreq.h>
17 #include <linux/cpumask.h>
18 #include <linux/cpu_cooling.h>
19 #include <linux/device.h>
20 #include <linux/module.h>
21 #include <linux/mutex.h>
22 #include <linux/of_platform.h>
23 #include <linux/platform_device.h>
24 #include <linux/pm_opp.h>
25 #include <linux/slab.h>
26 #include <linux/topology.h>
27 #include <linux/types.h>
29 /* Currently we support only two clusters */
30 #define A15_CLUSTER 0
31 #define A7_CLUSTER 1
32 #define MAX_CLUSTERS 2
34 #ifdef CONFIG_BL_SWITCHER
35 #include <asm/bL_switcher.h>
36 static bool bL_switching_enabled;
37 #define is_bL_switching_enabled() bL_switching_enabled
38 #define set_switching_enabled(x) (bL_switching_enabled = (x))
39 #else
40 #define is_bL_switching_enabled() false
41 #define set_switching_enabled(x) do { } while (0)
42 #define bL_switch_request(...) do { } while (0)
43 #define bL_switcher_put_enabled() do { } while (0)
44 #define bL_switcher_get_enabled() do { } while (0)
45 #endif
47 #define ACTUAL_FREQ(cluster, freq) ((cluster == A7_CLUSTER) ? freq << 1 : freq)
48 #define VIRT_FREQ(cluster, freq) ((cluster == A7_CLUSTER) ? freq >> 1 : freq)
50 static struct thermal_cooling_device *cdev[MAX_CLUSTERS];
51 static struct clk *clk[MAX_CLUSTERS];
52 static struct cpufreq_frequency_table *freq_table[MAX_CLUSTERS + 1];
53 static atomic_t cluster_usage[MAX_CLUSTERS + 1];
55 static unsigned int clk_big_min; /* (Big) clock frequencies */
56 static unsigned int clk_little_max; /* Maximum clock frequency (Little) */
58 static DEFINE_PER_CPU(unsigned int, physical_cluster);
59 static DEFINE_PER_CPU(unsigned int, cpu_last_req_freq);
61 static struct mutex cluster_lock[MAX_CLUSTERS];
63 static inline int raw_cpu_to_cluster(int cpu)
65 return topology_physical_package_id(cpu);
68 static inline int cpu_to_cluster(int cpu)
70 return is_bL_switching_enabled() ?
71 MAX_CLUSTERS : raw_cpu_to_cluster(cpu);
74 static unsigned int find_cluster_maxfreq(int cluster)
76 int j;
77 u32 max_freq = 0, cpu_freq;
79 for_each_online_cpu(j) {
80 cpu_freq = per_cpu(cpu_last_req_freq, j);
82 if (cluster == per_cpu(physical_cluster, j) &&
83 max_freq < cpu_freq)
84 max_freq = cpu_freq;
87 return max_freq;
90 static unsigned int clk_get_cpu_rate(unsigned int cpu)
92 u32 cur_cluster = per_cpu(physical_cluster, cpu);
93 u32 rate = clk_get_rate(clk[cur_cluster]) / 1000;
95 /* For switcher we use virtual A7 clock rates */
96 if (is_bL_switching_enabled())
97 rate = VIRT_FREQ(cur_cluster, rate);
99 return rate;
102 static unsigned int ve_spc_cpufreq_get_rate(unsigned int cpu)
104 if (is_bL_switching_enabled())
105 return per_cpu(cpu_last_req_freq, cpu);
106 else
107 return clk_get_cpu_rate(cpu);
110 static unsigned int
111 ve_spc_cpufreq_set_rate(u32 cpu, u32 old_cluster, u32 new_cluster, u32 rate)
113 u32 new_rate, prev_rate;
114 int ret;
115 bool bLs = is_bL_switching_enabled();
117 mutex_lock(&cluster_lock[new_cluster]);
119 if (bLs) {
120 prev_rate = per_cpu(cpu_last_req_freq, cpu);
121 per_cpu(cpu_last_req_freq, cpu) = rate;
122 per_cpu(physical_cluster, cpu) = new_cluster;
124 new_rate = find_cluster_maxfreq(new_cluster);
125 new_rate = ACTUAL_FREQ(new_cluster, new_rate);
126 } else {
127 new_rate = rate;
130 ret = clk_set_rate(clk[new_cluster], new_rate * 1000);
131 if (!ret) {
133 * FIXME: clk_set_rate hasn't returned an error here however it
134 * may be that clk_change_rate failed due to hardware or
135 * firmware issues and wasn't able to report that due to the
136 * current design of the clk core layer. To work around this
137 * problem we will read back the clock rate and check it is
138 * correct. This needs to be removed once clk core is fixed.
140 if (clk_get_rate(clk[new_cluster]) != new_rate * 1000)
141 ret = -EIO;
144 if (WARN_ON(ret)) {
145 if (bLs) {
146 per_cpu(cpu_last_req_freq, cpu) = prev_rate;
147 per_cpu(physical_cluster, cpu) = old_cluster;
150 mutex_unlock(&cluster_lock[new_cluster]);
152 return ret;
155 mutex_unlock(&cluster_lock[new_cluster]);
157 /* Recalc freq for old cluster when switching clusters */
158 if (old_cluster != new_cluster) {
159 /* Switch cluster */
160 bL_switch_request(cpu, new_cluster);
162 mutex_lock(&cluster_lock[old_cluster]);
164 /* Set freq of old cluster if there are cpus left on it */
165 new_rate = find_cluster_maxfreq(old_cluster);
166 new_rate = ACTUAL_FREQ(old_cluster, new_rate);
168 if (new_rate &&
169 clk_set_rate(clk[old_cluster], new_rate * 1000)) {
170 pr_err("%s: clk_set_rate failed: %d, old cluster: %d\n",
171 __func__, ret, old_cluster);
173 mutex_unlock(&cluster_lock[old_cluster]);
176 return 0;
179 /* Set clock frequency */
180 static int ve_spc_cpufreq_set_target(struct cpufreq_policy *policy,
181 unsigned int index)
183 u32 cpu = policy->cpu, cur_cluster, new_cluster, actual_cluster;
184 unsigned int freqs_new;
186 cur_cluster = cpu_to_cluster(cpu);
187 new_cluster = actual_cluster = per_cpu(physical_cluster, cpu);
189 freqs_new = freq_table[cur_cluster][index].frequency;
191 if (is_bL_switching_enabled()) {
192 if (actual_cluster == A15_CLUSTER && freqs_new < clk_big_min)
193 new_cluster = A7_CLUSTER;
194 else if (actual_cluster == A7_CLUSTER &&
195 freqs_new > clk_little_max)
196 new_cluster = A15_CLUSTER;
199 return ve_spc_cpufreq_set_rate(cpu, actual_cluster, new_cluster,
200 freqs_new);
203 static inline u32 get_table_count(struct cpufreq_frequency_table *table)
205 int count;
207 for (count = 0; table[count].frequency != CPUFREQ_TABLE_END; count++)
210 return count;
213 /* get the minimum frequency in the cpufreq_frequency_table */
214 static inline u32 get_table_min(struct cpufreq_frequency_table *table)
216 struct cpufreq_frequency_table *pos;
217 u32 min_freq = ~0;
219 cpufreq_for_each_entry(pos, table)
220 if (pos->frequency < min_freq)
221 min_freq = pos->frequency;
222 return min_freq;
225 /* get the maximum frequency in the cpufreq_frequency_table */
226 static inline u32 get_table_max(struct cpufreq_frequency_table *table)
228 struct cpufreq_frequency_table *pos;
229 u32 max_freq = 0;
231 cpufreq_for_each_entry(pos, table)
232 if (pos->frequency > max_freq)
233 max_freq = pos->frequency;
234 return max_freq;
237 static bool search_frequency(struct cpufreq_frequency_table *table, int size,
238 unsigned int freq)
240 int count;
242 for (count = 0; count < size; count++) {
243 if (table[count].frequency == freq)
244 return true;
247 return false;
250 static int merge_cluster_tables(void)
252 int i, j, k = 0, count = 1;
253 struct cpufreq_frequency_table *table;
255 for (i = 0; i < MAX_CLUSTERS; i++)
256 count += get_table_count(freq_table[i]);
258 table = kcalloc(count, sizeof(*table), GFP_KERNEL);
259 if (!table)
260 return -ENOMEM;
262 freq_table[MAX_CLUSTERS] = table;
264 /* Add in reverse order to get freqs in increasing order */
265 for (i = MAX_CLUSTERS - 1; i >= 0; i--, count = k) {
266 for (j = 0; freq_table[i][j].frequency != CPUFREQ_TABLE_END;
267 j++) {
268 if (i == A15_CLUSTER &&
269 search_frequency(table, count, freq_table[i][j].frequency))
270 continue; /* skip duplicates */
271 table[k++].frequency =
272 VIRT_FREQ(i, freq_table[i][j].frequency);
276 table[k].driver_data = k;
277 table[k].frequency = CPUFREQ_TABLE_END;
279 return 0;
282 static void _put_cluster_clk_and_freq_table(struct device *cpu_dev,
283 const struct cpumask *cpumask)
285 u32 cluster = raw_cpu_to_cluster(cpu_dev->id);
287 if (!freq_table[cluster])
288 return;
290 clk_put(clk[cluster]);
291 dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table[cluster]);
294 static void put_cluster_clk_and_freq_table(struct device *cpu_dev,
295 const struct cpumask *cpumask)
297 u32 cluster = cpu_to_cluster(cpu_dev->id);
298 int i;
300 if (atomic_dec_return(&cluster_usage[cluster]))
301 return;
303 if (cluster < MAX_CLUSTERS)
304 return _put_cluster_clk_and_freq_table(cpu_dev, cpumask);
306 for_each_present_cpu(i) {
307 struct device *cdev = get_cpu_device(i);
309 if (!cdev)
310 return;
312 _put_cluster_clk_and_freq_table(cdev, cpumask);
315 /* free virtual table */
316 kfree(freq_table[cluster]);
319 static int _get_cluster_clk_and_freq_table(struct device *cpu_dev,
320 const struct cpumask *cpumask)
322 u32 cluster = raw_cpu_to_cluster(cpu_dev->id);
323 int ret;
325 if (freq_table[cluster])
326 return 0;
329 * platform specific SPC code must initialise the opp table
330 * so just check if the OPP count is non-zero
332 ret = dev_pm_opp_get_opp_count(cpu_dev) <= 0;
333 if (ret)
334 goto out;
336 ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table[cluster]);
337 if (ret)
338 goto out;
340 clk[cluster] = clk_get(cpu_dev, NULL);
341 if (!IS_ERR(clk[cluster]))
342 return 0;
344 dev_err(cpu_dev, "%s: Failed to get clk for cpu: %d, cluster: %d\n",
345 __func__, cpu_dev->id, cluster);
346 ret = PTR_ERR(clk[cluster]);
347 dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table[cluster]);
349 out:
350 dev_err(cpu_dev, "%s: Failed to get data for cluster: %d\n", __func__,
351 cluster);
352 return ret;
355 static int get_cluster_clk_and_freq_table(struct device *cpu_dev,
356 const struct cpumask *cpumask)
358 u32 cluster = cpu_to_cluster(cpu_dev->id);
359 int i, ret;
361 if (atomic_inc_return(&cluster_usage[cluster]) != 1)
362 return 0;
364 if (cluster < MAX_CLUSTERS) {
365 ret = _get_cluster_clk_and_freq_table(cpu_dev, cpumask);
366 if (ret)
367 atomic_dec(&cluster_usage[cluster]);
368 return ret;
372 * Get data for all clusters and fill virtual cluster with a merge of
373 * both
375 for_each_present_cpu(i) {
376 struct device *cdev = get_cpu_device(i);
378 if (!cdev)
379 return -ENODEV;
381 ret = _get_cluster_clk_and_freq_table(cdev, cpumask);
382 if (ret)
383 goto put_clusters;
386 ret = merge_cluster_tables();
387 if (ret)
388 goto put_clusters;
390 /* Assuming 2 cluster, set clk_big_min and clk_little_max */
391 clk_big_min = get_table_min(freq_table[A15_CLUSTER]);
392 clk_little_max = VIRT_FREQ(A7_CLUSTER,
393 get_table_max(freq_table[A7_CLUSTER]));
395 return 0;
397 put_clusters:
398 for_each_present_cpu(i) {
399 struct device *cdev = get_cpu_device(i);
401 if (!cdev)
402 return -ENODEV;
404 _put_cluster_clk_and_freq_table(cdev, cpumask);
407 atomic_dec(&cluster_usage[cluster]);
409 return ret;
412 /* Per-CPU initialization */
413 static int ve_spc_cpufreq_init(struct cpufreq_policy *policy)
415 u32 cur_cluster = cpu_to_cluster(policy->cpu);
416 struct device *cpu_dev;
417 int ret;
419 cpu_dev = get_cpu_device(policy->cpu);
420 if (!cpu_dev) {
421 pr_err("%s: failed to get cpu%d device\n", __func__,
422 policy->cpu);
423 return -ENODEV;
426 if (cur_cluster < MAX_CLUSTERS) {
427 int cpu;
429 dev_pm_opp_get_sharing_cpus(cpu_dev, policy->cpus);
431 for_each_cpu(cpu, policy->cpus)
432 per_cpu(physical_cluster, cpu) = cur_cluster;
433 } else {
434 /* Assumption: during init, we are always running on A15 */
435 per_cpu(physical_cluster, policy->cpu) = A15_CLUSTER;
438 ret = get_cluster_clk_and_freq_table(cpu_dev, policy->cpus);
439 if (ret)
440 return ret;
442 policy->freq_table = freq_table[cur_cluster];
443 policy->cpuinfo.transition_latency = 1000000; /* 1 ms */
445 dev_pm_opp_of_register_em(cpu_dev, policy->cpus);
447 if (is_bL_switching_enabled())
448 per_cpu(cpu_last_req_freq, policy->cpu) =
449 clk_get_cpu_rate(policy->cpu);
451 dev_info(cpu_dev, "%s: CPU %d initialized\n", __func__, policy->cpu);
452 return 0;
455 static int ve_spc_cpufreq_exit(struct cpufreq_policy *policy)
457 struct device *cpu_dev;
458 int cur_cluster = cpu_to_cluster(policy->cpu);
460 if (cur_cluster < MAX_CLUSTERS) {
461 cpufreq_cooling_unregister(cdev[cur_cluster]);
462 cdev[cur_cluster] = NULL;
465 cpu_dev = get_cpu_device(policy->cpu);
466 if (!cpu_dev) {
467 pr_err("%s: failed to get cpu%d device\n", __func__,
468 policy->cpu);
469 return -ENODEV;
472 put_cluster_clk_and_freq_table(cpu_dev, policy->related_cpus);
473 return 0;
476 static void ve_spc_cpufreq_ready(struct cpufreq_policy *policy)
478 int cur_cluster = cpu_to_cluster(policy->cpu);
480 /* Do not register a cpu_cooling device if we are in IKS mode */
481 if (cur_cluster >= MAX_CLUSTERS)
482 return;
484 cdev[cur_cluster] = of_cpufreq_cooling_register(policy);
487 static struct cpufreq_driver ve_spc_cpufreq_driver = {
488 .name = "vexpress-spc",
489 .flags = CPUFREQ_STICKY |
490 CPUFREQ_HAVE_GOVERNOR_PER_POLICY |
491 CPUFREQ_NEED_INITIAL_FREQ_CHECK,
492 .verify = cpufreq_generic_frequency_table_verify,
493 .target_index = ve_spc_cpufreq_set_target,
494 .get = ve_spc_cpufreq_get_rate,
495 .init = ve_spc_cpufreq_init,
496 .exit = ve_spc_cpufreq_exit,
497 .ready = ve_spc_cpufreq_ready,
498 .attr = cpufreq_generic_attr,
501 #ifdef CONFIG_BL_SWITCHER
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);
507 switch (action) {
508 case BL_NOTIFY_PRE_ENABLE:
509 case BL_NOTIFY_PRE_DISABLE:
510 cpufreq_unregister_driver(&ve_spc_cpufreq_driver);
511 break;
513 case BL_NOTIFY_POST_ENABLE:
514 set_switching_enabled(true);
515 cpufreq_register_driver(&ve_spc_cpufreq_driver);
516 break;
518 case BL_NOTIFY_POST_DISABLE:
519 set_switching_enabled(false);
520 cpufreq_register_driver(&ve_spc_cpufreq_driver);
521 break;
523 default:
524 return NOTIFY_DONE;
527 return NOTIFY_OK;
530 static struct notifier_block bL_switcher_notifier = {
531 .notifier_call = bL_cpufreq_switcher_notifier,
534 static int __bLs_register_notifier(void)
536 return bL_switcher_register_notifier(&bL_switcher_notifier);
539 static int __bLs_unregister_notifier(void)
541 return bL_switcher_unregister_notifier(&bL_switcher_notifier);
543 #else
544 static int __bLs_register_notifier(void) { return 0; }
545 static int __bLs_unregister_notifier(void) { return 0; }
546 #endif
548 static int ve_spc_cpufreq_probe(struct platform_device *pdev)
550 int ret, i;
552 set_switching_enabled(bL_switcher_get_enabled());
554 for (i = 0; i < MAX_CLUSTERS; i++)
555 mutex_init(&cluster_lock[i]);
557 ret = cpufreq_register_driver(&ve_spc_cpufreq_driver);
558 if (ret) {
559 pr_info("%s: Failed registering platform driver: %s, err: %d\n",
560 __func__, ve_spc_cpufreq_driver.name, ret);
561 } else {
562 ret = __bLs_register_notifier();
563 if (ret)
564 cpufreq_unregister_driver(&ve_spc_cpufreq_driver);
565 else
566 pr_info("%s: Registered platform driver: %s\n",
567 __func__, ve_spc_cpufreq_driver.name);
570 bL_switcher_put_enabled();
571 return ret;
574 static int ve_spc_cpufreq_remove(struct platform_device *pdev)
576 bL_switcher_get_enabled();
577 __bLs_unregister_notifier();
578 cpufreq_unregister_driver(&ve_spc_cpufreq_driver);
579 bL_switcher_put_enabled();
580 pr_info("%s: Un-registered platform driver: %s\n", __func__,
581 ve_spc_cpufreq_driver.name);
582 return 0;
585 static struct platform_driver ve_spc_cpufreq_platdrv = {
586 .driver = {
587 .name = "vexpress-spc-cpufreq",
589 .probe = ve_spc_cpufreq_probe,
590 .remove = ve_spc_cpufreq_remove,
592 module_platform_driver(ve_spc_cpufreq_platdrv);
594 MODULE_ALIAS("platform:vexpress-spc-cpufreq");
595 MODULE_AUTHOR("Viresh Kumar <viresh.kumar@linaro.org>");
596 MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>");
597 MODULE_DESCRIPTION("Vexpress SPC ARM big LITTLE cpufreq driver");
598 MODULE_LICENSE("GPL v2");