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