GNU Linux-libre 5.19-rc6-gnu
[releases.git] / drivers / cpufreq / vexpress-spc-cpufreq.c
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Versatile Express SPC CPUFreq Interface driver
4  *
5  * Copyright (C) 2013 - 2019 ARM Ltd.
6  * Sudeep Holla <sudeep.holla@arm.com>
7  *
8  * Copyright (C) 2013 Linaro.
9  * Viresh Kumar <viresh.kumar@linaro.org>
10  */
11
12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
13
14 #include <linux/clk.h>
15 #include <linux/cpu.h>
16 #include <linux/cpufreq.h>
17 #include <linux/cpumask.h>
18 #include <linux/device.h>
19 #include <linux/module.h>
20 #include <linux/mutex.h>
21 #include <linux/of_platform.h>
22 #include <linux/platform_device.h>
23 #include <linux/pm_opp.h>
24 #include <linux/slab.h>
25 #include <linux/topology.h>
26 #include <linux/types.h>
27
28 /* Currently we support only two clusters */
29 #define A15_CLUSTER     0
30 #define A7_CLUSTER      1
31 #define MAX_CLUSTERS    2
32
33 #ifdef CONFIG_BL_SWITCHER
34 #include <asm/bL_switcher.h>
35 static bool bL_switching_enabled;
36 #define is_bL_switching_enabled()       bL_switching_enabled
37 #define set_switching_enabled(x)        (bL_switching_enabled = (x))
38 #else
39 #define is_bL_switching_enabled()       false
40 #define set_switching_enabled(x)        do { } while (0)
41 #define bL_switch_request(...)          do { } while (0)
42 #define bL_switcher_put_enabled()       do { } while (0)
43 #define bL_switcher_get_enabled()       do { } while (0)
44 #endif
45
46 #define ACTUAL_FREQ(cluster, freq)  ((cluster == A7_CLUSTER) ? freq << 1 : freq)
47 #define VIRT_FREQ(cluster, freq)    ((cluster == A7_CLUSTER) ? freq >> 1 : freq)
48
49 static struct clk *clk[MAX_CLUSTERS];
50 static struct cpufreq_frequency_table *freq_table[MAX_CLUSTERS + 1];
51 static atomic_t cluster_usage[MAX_CLUSTERS + 1];
52
53 static unsigned int clk_big_min;        /* (Big) clock frequencies */
54 static unsigned int clk_little_max;     /* Maximum clock frequency (Little) */
55
56 static DEFINE_PER_CPU(unsigned int, physical_cluster);
57 static DEFINE_PER_CPU(unsigned int, cpu_last_req_freq);
58
59 static struct mutex cluster_lock[MAX_CLUSTERS];
60
61 static inline int raw_cpu_to_cluster(int cpu)
62 {
63         return topology_physical_package_id(cpu);
64 }
65
66 static inline int cpu_to_cluster(int cpu)
67 {
68         return is_bL_switching_enabled() ?
69                 MAX_CLUSTERS : raw_cpu_to_cluster(cpu);
70 }
71
72 static unsigned int find_cluster_maxfreq(int cluster)
73 {
74         int j;
75         u32 max_freq = 0, cpu_freq;
76
77         for_each_online_cpu(j) {
78                 cpu_freq = per_cpu(cpu_last_req_freq, j);
79
80                 if (cluster == per_cpu(physical_cluster, j) &&
81                     max_freq < cpu_freq)
82                         max_freq = cpu_freq;
83         }
84
85         return max_freq;
86 }
87
88 static unsigned int clk_get_cpu_rate(unsigned int cpu)
89 {
90         u32 cur_cluster = per_cpu(physical_cluster, cpu);
91         u32 rate = clk_get_rate(clk[cur_cluster]) / 1000;
92
93         /* For switcher we use virtual A7 clock rates */
94         if (is_bL_switching_enabled())
95                 rate = VIRT_FREQ(cur_cluster, rate);
96
97         return rate;
98 }
99
100 static unsigned int ve_spc_cpufreq_get_rate(unsigned int cpu)
101 {
102         if (is_bL_switching_enabled())
103                 return per_cpu(cpu_last_req_freq, cpu);
104         else
105                 return clk_get_cpu_rate(cpu);
106 }
107
108 static unsigned int
109 ve_spc_cpufreq_set_rate(u32 cpu, u32 old_cluster, u32 new_cluster, u32 rate)
110 {
111         u32 new_rate, prev_rate;
112         int ret;
113         bool bLs = is_bL_switching_enabled();
114
115         mutex_lock(&cluster_lock[new_cluster]);
116
117         if (bLs) {
118                 prev_rate = per_cpu(cpu_last_req_freq, cpu);
119                 per_cpu(cpu_last_req_freq, cpu) = rate;
120                 per_cpu(physical_cluster, cpu) = new_cluster;
121
122                 new_rate = find_cluster_maxfreq(new_cluster);
123                 new_rate = ACTUAL_FREQ(new_cluster, new_rate);
124         } else {
125                 new_rate = rate;
126         }
127
128         ret = clk_set_rate(clk[new_cluster], new_rate * 1000);
129         if (!ret) {
130                 /*
131                  * FIXME: clk_set_rate hasn't returned an error here however it
132                  * may be that clk_change_rate failed due to hardware or
133                  * firmware issues and wasn't able to report that due to the
134                  * current design of the clk core layer. To work around this
135                  * problem we will read back the clock rate and check it is
136                  * correct. This needs to be removed once clk core is fixed.
137                  */
138                 if (clk_get_rate(clk[new_cluster]) != new_rate * 1000)
139                         ret = -EIO;
140         }
141
142         if (WARN_ON(ret)) {
143                 if (bLs) {
144                         per_cpu(cpu_last_req_freq, cpu) = prev_rate;
145                         per_cpu(physical_cluster, cpu) = old_cluster;
146                 }
147
148                 mutex_unlock(&cluster_lock[new_cluster]);
149
150                 return ret;
151         }
152
153         mutex_unlock(&cluster_lock[new_cluster]);
154
155         /* Recalc freq for old cluster when switching clusters */
156         if (old_cluster != new_cluster) {
157                 /* Switch cluster */
158                 bL_switch_request(cpu, new_cluster);
159
160                 mutex_lock(&cluster_lock[old_cluster]);
161
162                 /* Set freq of old cluster if there are cpus left on it */
163                 new_rate = find_cluster_maxfreq(old_cluster);
164                 new_rate = ACTUAL_FREQ(old_cluster, new_rate);
165
166                 if (new_rate &&
167                     clk_set_rate(clk[old_cluster], new_rate * 1000)) {
168                         pr_err("%s: clk_set_rate failed: %d, old cluster: %d\n",
169                                __func__, ret, old_cluster);
170                 }
171                 mutex_unlock(&cluster_lock[old_cluster]);
172         }
173
174         return 0;
175 }
176
177 /* Set clock frequency */
178 static int ve_spc_cpufreq_set_target(struct cpufreq_policy *policy,
179                                      unsigned int index)
180 {
181         u32 cpu = policy->cpu, cur_cluster, new_cluster, actual_cluster;
182         unsigned int freqs_new;
183
184         cur_cluster = cpu_to_cluster(cpu);
185         new_cluster = actual_cluster = per_cpu(physical_cluster, cpu);
186
187         freqs_new = freq_table[cur_cluster][index].frequency;
188
189         if (is_bL_switching_enabled()) {
190                 if (actual_cluster == A15_CLUSTER && freqs_new < clk_big_min)
191                         new_cluster = A7_CLUSTER;
192                 else if (actual_cluster == A7_CLUSTER &&
193                          freqs_new > clk_little_max)
194                         new_cluster = A15_CLUSTER;
195         }
196
197         return ve_spc_cpufreq_set_rate(cpu, actual_cluster, new_cluster,
198                                        freqs_new);
199 }
200
201 static inline u32 get_table_count(struct cpufreq_frequency_table *table)
202 {
203         int count;
204
205         for (count = 0; table[count].frequency != CPUFREQ_TABLE_END; count++)
206                 ;
207
208         return count;
209 }
210
211 /* get the minimum frequency in the cpufreq_frequency_table */
212 static inline u32 get_table_min(struct cpufreq_frequency_table *table)
213 {
214         struct cpufreq_frequency_table *pos;
215         u32 min_freq = ~0;
216
217         cpufreq_for_each_entry(pos, table)
218                 if (pos->frequency < min_freq)
219                         min_freq = pos->frequency;
220         return min_freq;
221 }
222
223 /* get the maximum frequency in the cpufreq_frequency_table */
224 static inline u32 get_table_max(struct cpufreq_frequency_table *table)
225 {
226         struct cpufreq_frequency_table *pos;
227         u32 max_freq = 0;
228
229         cpufreq_for_each_entry(pos, table)
230                 if (pos->frequency > max_freq)
231                         max_freq = pos->frequency;
232         return max_freq;
233 }
234
235 static bool search_frequency(struct cpufreq_frequency_table *table, int size,
236                              unsigned int freq)
237 {
238         int count;
239
240         for (count = 0; count < size; count++) {
241                 if (table[count].frequency == freq)
242                         return true;
243         }
244
245         return false;
246 }
247
248 static int merge_cluster_tables(void)
249 {
250         int i, j, k = 0, count = 1;
251         struct cpufreq_frequency_table *table;
252
253         for (i = 0; i < MAX_CLUSTERS; i++)
254                 count += get_table_count(freq_table[i]);
255
256         table = kcalloc(count, sizeof(*table), GFP_KERNEL);
257         if (!table)
258                 return -ENOMEM;
259
260         freq_table[MAX_CLUSTERS] = table;
261
262         /* Add in reverse order to get freqs in increasing order */
263         for (i = MAX_CLUSTERS - 1; i >= 0; i--, count = k) {
264                 for (j = 0; freq_table[i][j].frequency != CPUFREQ_TABLE_END;
265                      j++) {
266                         if (i == A15_CLUSTER &&
267                             search_frequency(table, count, freq_table[i][j].frequency))
268                                 continue; /* skip duplicates */
269                         table[k++].frequency =
270                                 VIRT_FREQ(i, freq_table[i][j].frequency);
271                 }
272         }
273
274         table[k].driver_data = k;
275         table[k].frequency = CPUFREQ_TABLE_END;
276
277         return 0;
278 }
279
280 static void _put_cluster_clk_and_freq_table(struct device *cpu_dev,
281                                             const struct cpumask *cpumask)
282 {
283         u32 cluster = raw_cpu_to_cluster(cpu_dev->id);
284
285         if (!freq_table[cluster])
286                 return;
287
288         clk_put(clk[cluster]);
289         dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table[cluster]);
290 }
291
292 static void put_cluster_clk_and_freq_table(struct device *cpu_dev,
293                                            const struct cpumask *cpumask)
294 {
295         u32 cluster = cpu_to_cluster(cpu_dev->id);
296         int i;
297
298         if (atomic_dec_return(&cluster_usage[cluster]))
299                 return;
300
301         if (cluster < MAX_CLUSTERS)
302                 return _put_cluster_clk_and_freq_table(cpu_dev, cpumask);
303
304         for_each_present_cpu(i) {
305                 struct device *cdev = get_cpu_device(i);
306
307                 if (!cdev)
308                         return;
309
310                 _put_cluster_clk_and_freq_table(cdev, cpumask);
311         }
312
313         /* free virtual table */
314         kfree(freq_table[cluster]);
315 }
316
317 static int _get_cluster_clk_and_freq_table(struct device *cpu_dev,
318                                            const struct cpumask *cpumask)
319 {
320         u32 cluster = raw_cpu_to_cluster(cpu_dev->id);
321         int ret;
322
323         if (freq_table[cluster])
324                 return 0;
325
326         /*
327          * platform specific SPC code must initialise the opp table
328          * so just check if the OPP count is non-zero
329          */
330         ret = dev_pm_opp_get_opp_count(cpu_dev) <= 0;
331         if (ret)
332                 goto out;
333
334         ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table[cluster]);
335         if (ret)
336                 goto out;
337
338         clk[cluster] = clk_get(cpu_dev, NULL);
339         if (!IS_ERR(clk[cluster]))
340                 return 0;
341
342         dev_err(cpu_dev, "%s: Failed to get clk for cpu: %d, cluster: %d\n",
343                 __func__, cpu_dev->id, cluster);
344         ret = PTR_ERR(clk[cluster]);
345         dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table[cluster]);
346
347 out:
348         dev_err(cpu_dev, "%s: Failed to get data for cluster: %d\n", __func__,
349                 cluster);
350         return ret;
351 }
352
353 static int get_cluster_clk_and_freq_table(struct device *cpu_dev,
354                                           const struct cpumask *cpumask)
355 {
356         u32 cluster = cpu_to_cluster(cpu_dev->id);
357         int i, ret;
358
359         if (atomic_inc_return(&cluster_usage[cluster]) != 1)
360                 return 0;
361
362         if (cluster < MAX_CLUSTERS) {
363                 ret = _get_cluster_clk_and_freq_table(cpu_dev, cpumask);
364                 if (ret)
365                         atomic_dec(&cluster_usage[cluster]);
366                 return ret;
367         }
368
369         /*
370          * Get data for all clusters and fill virtual cluster with a merge of
371          * both
372          */
373         for_each_present_cpu(i) {
374                 struct device *cdev = get_cpu_device(i);
375
376                 if (!cdev)
377                         return -ENODEV;
378
379                 ret = _get_cluster_clk_and_freq_table(cdev, cpumask);
380                 if (ret)
381                         goto put_clusters;
382         }
383
384         ret = merge_cluster_tables();
385         if (ret)
386                 goto put_clusters;
387
388         /* Assuming 2 cluster, set clk_big_min and clk_little_max */
389         clk_big_min = get_table_min(freq_table[A15_CLUSTER]);
390         clk_little_max = VIRT_FREQ(A7_CLUSTER,
391                                    get_table_max(freq_table[A7_CLUSTER]));
392
393         return 0;
394
395 put_clusters:
396         for_each_present_cpu(i) {
397                 struct device *cdev = get_cpu_device(i);
398
399                 if (!cdev)
400                         return -ENODEV;
401
402                 _put_cluster_clk_and_freq_table(cdev, cpumask);
403         }
404
405         atomic_dec(&cluster_usage[cluster]);
406
407         return ret;
408 }
409
410 /* Per-CPU initialization */
411 static int ve_spc_cpufreq_init(struct cpufreq_policy *policy)
412 {
413         u32 cur_cluster = cpu_to_cluster(policy->cpu);
414         struct device *cpu_dev;
415         int ret;
416
417         cpu_dev = get_cpu_device(policy->cpu);
418         if (!cpu_dev) {
419                 pr_err("%s: failed to get cpu%d device\n", __func__,
420                        policy->cpu);
421                 return -ENODEV;
422         }
423
424         if (cur_cluster < MAX_CLUSTERS) {
425                 int cpu;
426
427                 dev_pm_opp_get_sharing_cpus(cpu_dev, policy->cpus);
428
429                 for_each_cpu(cpu, policy->cpus)
430                         per_cpu(physical_cluster, cpu) = cur_cluster;
431         } else {
432                 /* Assumption: during init, we are always running on A15 */
433                 per_cpu(physical_cluster, policy->cpu) = A15_CLUSTER;
434         }
435
436         ret = get_cluster_clk_and_freq_table(cpu_dev, policy->cpus);
437         if (ret)
438                 return ret;
439
440         policy->freq_table = freq_table[cur_cluster];
441         policy->cpuinfo.transition_latency = 1000000; /* 1 ms */
442
443         if (is_bL_switching_enabled())
444                 per_cpu(cpu_last_req_freq, policy->cpu) =
445                                                 clk_get_cpu_rate(policy->cpu);
446
447         dev_info(cpu_dev, "%s: CPU %d initialized\n", __func__, policy->cpu);
448         return 0;
449 }
450
451 static int ve_spc_cpufreq_exit(struct cpufreq_policy *policy)
452 {
453         struct device *cpu_dev;
454
455         cpu_dev = get_cpu_device(policy->cpu);
456         if (!cpu_dev) {
457                 pr_err("%s: failed to get cpu%d device\n", __func__,
458                        policy->cpu);
459                 return -ENODEV;
460         }
461
462         put_cluster_clk_and_freq_table(cpu_dev, policy->related_cpus);
463         return 0;
464 }
465
466 static struct cpufreq_driver ve_spc_cpufreq_driver = {
467         .name                   = "vexpress-spc",
468         .flags                  = CPUFREQ_HAVE_GOVERNOR_PER_POLICY |
469                                         CPUFREQ_NEED_INITIAL_FREQ_CHECK,
470         .verify                 = cpufreq_generic_frequency_table_verify,
471         .target_index           = ve_spc_cpufreq_set_target,
472         .get                    = ve_spc_cpufreq_get_rate,
473         .init                   = ve_spc_cpufreq_init,
474         .exit                   = ve_spc_cpufreq_exit,
475         .register_em            = cpufreq_register_em_with_opp,
476         .attr                   = cpufreq_generic_attr,
477 };
478
479 #ifdef CONFIG_BL_SWITCHER
480 static int bL_cpufreq_switcher_notifier(struct notifier_block *nfb,
481                                         unsigned long action, void *_arg)
482 {
483         pr_debug("%s: action: %ld\n", __func__, action);
484
485         switch (action) {
486         case BL_NOTIFY_PRE_ENABLE:
487         case BL_NOTIFY_PRE_DISABLE:
488                 cpufreq_unregister_driver(&ve_spc_cpufreq_driver);
489                 break;
490
491         case BL_NOTIFY_POST_ENABLE:
492                 set_switching_enabled(true);
493                 cpufreq_register_driver(&ve_spc_cpufreq_driver);
494                 break;
495
496         case BL_NOTIFY_POST_DISABLE:
497                 set_switching_enabled(false);
498                 cpufreq_register_driver(&ve_spc_cpufreq_driver);
499                 break;
500
501         default:
502                 return NOTIFY_DONE;
503         }
504
505         return NOTIFY_OK;
506 }
507
508 static struct notifier_block bL_switcher_notifier = {
509         .notifier_call = bL_cpufreq_switcher_notifier,
510 };
511
512 static int __bLs_register_notifier(void)
513 {
514         return bL_switcher_register_notifier(&bL_switcher_notifier);
515 }
516
517 static int __bLs_unregister_notifier(void)
518 {
519         return bL_switcher_unregister_notifier(&bL_switcher_notifier);
520 }
521 #else
522 static int __bLs_register_notifier(void) { return 0; }
523 static int __bLs_unregister_notifier(void) { return 0; }
524 #endif
525
526 static int ve_spc_cpufreq_probe(struct platform_device *pdev)
527 {
528         int ret, i;
529
530         set_switching_enabled(bL_switcher_get_enabled());
531
532         for (i = 0; i < MAX_CLUSTERS; i++)
533                 mutex_init(&cluster_lock[i]);
534
535         if (!is_bL_switching_enabled())
536                 ve_spc_cpufreq_driver.flags |= CPUFREQ_IS_COOLING_DEV;
537
538         ret = cpufreq_register_driver(&ve_spc_cpufreq_driver);
539         if (ret) {
540                 pr_info("%s: Failed registering platform driver: %s, err: %d\n",
541                         __func__, ve_spc_cpufreq_driver.name, ret);
542         } else {
543                 ret = __bLs_register_notifier();
544                 if (ret)
545                         cpufreq_unregister_driver(&ve_spc_cpufreq_driver);
546                 else
547                         pr_info("%s: Registered platform driver: %s\n",
548                                 __func__, ve_spc_cpufreq_driver.name);
549         }
550
551         bL_switcher_put_enabled();
552         return ret;
553 }
554
555 static int ve_spc_cpufreq_remove(struct platform_device *pdev)
556 {
557         bL_switcher_get_enabled();
558         __bLs_unregister_notifier();
559         cpufreq_unregister_driver(&ve_spc_cpufreq_driver);
560         bL_switcher_put_enabled();
561         pr_info("%s: Un-registered platform driver: %s\n", __func__,
562                 ve_spc_cpufreq_driver.name);
563         return 0;
564 }
565
566 static struct platform_driver ve_spc_cpufreq_platdrv = {
567         .driver = {
568                 .name   = "vexpress-spc-cpufreq",
569         },
570         .probe          = ve_spc_cpufreq_probe,
571         .remove         = ve_spc_cpufreq_remove,
572 };
573 module_platform_driver(ve_spc_cpufreq_platdrv);
574
575 MODULE_ALIAS("platform:vexpress-spc-cpufreq");
576 MODULE_AUTHOR("Viresh Kumar <viresh.kumar@linaro.org>");
577 MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>");
578 MODULE_DESCRIPTION("Vexpress SPC ARM big LITTLE cpufreq driver");
579 MODULE_LICENSE("GPL v2");