1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* |
3 | * SCMI Powercap support. |
4 | * |
5 | * Copyright (C) 2022 ARM Ltd. |
6 | */ |
7 | |
8 | #include <linux/device.h> |
9 | #include <linux/math.h> |
10 | #include <linux/limits.h> |
11 | #include <linux/list.h> |
12 | #include <linux/module.h> |
13 | #include <linux/powercap.h> |
14 | #include <linux/scmi_protocol.h> |
15 | #include <linux/slab.h> |
16 | |
17 | #define to_scmi_powercap_zone(z) \ |
18 | container_of(z, struct scmi_powercap_zone, zone) |
19 | |
20 | static const struct scmi_powercap_proto_ops *powercap_ops; |
21 | |
22 | struct scmi_powercap_zone { |
23 | bool registered; |
24 | bool invalid; |
25 | unsigned int height; |
26 | struct device *dev; |
27 | struct scmi_protocol_handle *ph; |
28 | const struct scmi_powercap_info *info; |
29 | struct scmi_powercap_zone *spzones; |
30 | struct powercap_zone zone; |
31 | struct list_head node; |
32 | }; |
33 | |
34 | struct scmi_powercap_root { |
35 | unsigned int num_zones; |
36 | struct scmi_powercap_zone *spzones; |
37 | struct list_head *registered_zones; |
38 | struct list_head scmi_zones; |
39 | }; |
40 | |
41 | static struct powercap_control_type *scmi_top_pcntrl; |
42 | |
43 | static int scmi_powercap_zone_release(struct powercap_zone *pz) |
44 | { |
45 | return 0; |
46 | } |
47 | |
48 | static int scmi_powercap_get_max_power_range_uw(struct powercap_zone *pz, |
49 | u64 *max_power_range_uw) |
50 | { |
51 | *max_power_range_uw = U32_MAX; |
52 | return 0; |
53 | } |
54 | |
55 | static int scmi_powercap_get_power_uw(struct powercap_zone *pz, |
56 | u64 *power_uw) |
57 | { |
58 | struct scmi_powercap_zone *spz = to_scmi_powercap_zone(pz); |
59 | u32 avg_power, pai; |
60 | int ret; |
61 | |
62 | if (!spz->info->powercap_monitoring) |
63 | return -EINVAL; |
64 | |
65 | ret = powercap_ops->measurements_get(spz->ph, spz->info->id, &avg_power, |
66 | &pai); |
67 | if (ret) |
68 | return ret; |
69 | |
70 | *power_uw = avg_power; |
71 | if (spz->info->powercap_scale_mw) |
72 | *power_uw *= 1000; |
73 | |
74 | return 0; |
75 | } |
76 | |
77 | static int scmi_powercap_zone_enable_set(struct powercap_zone *pz, bool mode) |
78 | { |
79 | struct scmi_powercap_zone *spz = to_scmi_powercap_zone(pz); |
80 | |
81 | return powercap_ops->cap_enable_set(spz->ph, spz->info->id, mode); |
82 | } |
83 | |
84 | static int scmi_powercap_zone_enable_get(struct powercap_zone *pz, bool *mode) |
85 | { |
86 | struct scmi_powercap_zone *spz = to_scmi_powercap_zone(pz); |
87 | |
88 | return powercap_ops->cap_enable_get(spz->ph, spz->info->id, mode); |
89 | } |
90 | |
91 | static const struct powercap_zone_ops zone_ops = { |
92 | .get_max_power_range_uw = scmi_powercap_get_max_power_range_uw, |
93 | .get_power_uw = scmi_powercap_get_power_uw, |
94 | .release = scmi_powercap_zone_release, |
95 | .set_enable = scmi_powercap_zone_enable_set, |
96 | .get_enable = scmi_powercap_zone_enable_get, |
97 | }; |
98 | |
99 | static void scmi_powercap_normalize_cap(const struct scmi_powercap_zone *spz, |
100 | u64 power_limit_uw, u32 *norm) |
101 | { |
102 | bool scale_mw = spz->info->powercap_scale_mw; |
103 | u64 val; |
104 | |
105 | val = scale_mw ? DIV_ROUND_UP_ULL(power_limit_uw, 1000) : power_limit_uw; |
106 | /* |
107 | * This cast is lossless since here @req_power is certain to be within |
108 | * the range [min_power_cap, max_power_cap] whose bounds are assured to |
109 | * be two unsigned 32bits quantities. |
110 | */ |
111 | *norm = clamp_t(u32, val, spz->info->min_power_cap, |
112 | spz->info->max_power_cap); |
113 | *norm = rounddown(*norm, spz->info->power_cap_step); |
114 | |
115 | val = (scale_mw) ? *norm * 1000 : *norm; |
116 | if (power_limit_uw != val) |
117 | dev_dbg(spz->dev, |
118 | "Normalized %s:CAP - requested:%llu - normalized:%llu\n" , |
119 | spz->info->name, power_limit_uw, val); |
120 | } |
121 | |
122 | static int scmi_powercap_set_power_limit_uw(struct powercap_zone *pz, int cid, |
123 | u64 power_uw) |
124 | { |
125 | struct scmi_powercap_zone *spz = to_scmi_powercap_zone(pz); |
126 | u32 norm_power; |
127 | |
128 | if (!spz->info->powercap_cap_config) |
129 | return -EINVAL; |
130 | |
131 | scmi_powercap_normalize_cap(spz, power_limit_uw: power_uw, norm: &norm_power); |
132 | |
133 | return powercap_ops->cap_set(spz->ph, spz->info->id, norm_power, false); |
134 | } |
135 | |
136 | static int scmi_powercap_get_power_limit_uw(struct powercap_zone *pz, int cid, |
137 | u64 *power_limit_uw) |
138 | { |
139 | struct scmi_powercap_zone *spz = to_scmi_powercap_zone(pz); |
140 | u32 power; |
141 | int ret; |
142 | |
143 | ret = powercap_ops->cap_get(spz->ph, spz->info->id, &power); |
144 | if (ret) |
145 | return ret; |
146 | |
147 | *power_limit_uw = power; |
148 | if (spz->info->powercap_scale_mw) |
149 | *power_limit_uw *= 1000; |
150 | |
151 | return 0; |
152 | } |
153 | |
154 | static void scmi_powercap_normalize_time(const struct scmi_powercap_zone *spz, |
155 | u64 time_us, u32 *norm) |
156 | { |
157 | /* |
158 | * This cast is lossless since here @time_us is certain to be within the |
159 | * range [min_pai, max_pai] whose bounds are assured to be two unsigned |
160 | * 32bits quantities. |
161 | */ |
162 | *norm = clamp_t(u32, time_us, spz->info->min_pai, spz->info->max_pai); |
163 | *norm = rounddown(*norm, spz->info->pai_step); |
164 | |
165 | if (time_us != *norm) |
166 | dev_dbg(spz->dev, |
167 | "Normalized %s:PAI - requested:%llu - normalized:%u\n" , |
168 | spz->info->name, time_us, *norm); |
169 | } |
170 | |
171 | static int scmi_powercap_set_time_window_us(struct powercap_zone *pz, int cid, |
172 | u64 time_window_us) |
173 | { |
174 | struct scmi_powercap_zone *spz = to_scmi_powercap_zone(pz); |
175 | u32 norm_pai; |
176 | |
177 | if (!spz->info->powercap_pai_config) |
178 | return -EINVAL; |
179 | |
180 | scmi_powercap_normalize_time(spz, time_us: time_window_us, norm: &norm_pai); |
181 | |
182 | return powercap_ops->pai_set(spz->ph, spz->info->id, norm_pai); |
183 | } |
184 | |
185 | static int scmi_powercap_get_time_window_us(struct powercap_zone *pz, int cid, |
186 | u64 *time_window_us) |
187 | { |
188 | struct scmi_powercap_zone *spz = to_scmi_powercap_zone(pz); |
189 | int ret; |
190 | u32 pai; |
191 | |
192 | ret = powercap_ops->pai_get(spz->ph, spz->info->id, &pai); |
193 | if (ret) |
194 | return ret; |
195 | |
196 | *time_window_us = pai; |
197 | |
198 | return 0; |
199 | } |
200 | |
201 | static int scmi_powercap_get_max_power_uw(struct powercap_zone *pz, int cid, |
202 | u64 *max_power_uw) |
203 | { |
204 | struct scmi_powercap_zone *spz = to_scmi_powercap_zone(pz); |
205 | |
206 | *max_power_uw = spz->info->max_power_cap; |
207 | if (spz->info->powercap_scale_mw) |
208 | *max_power_uw *= 1000; |
209 | |
210 | return 0; |
211 | } |
212 | |
213 | static int scmi_powercap_get_min_power_uw(struct powercap_zone *pz, int cid, |
214 | u64 *min_power_uw) |
215 | { |
216 | struct scmi_powercap_zone *spz = to_scmi_powercap_zone(pz); |
217 | |
218 | *min_power_uw = spz->info->min_power_cap; |
219 | if (spz->info->powercap_scale_mw) |
220 | *min_power_uw *= 1000; |
221 | |
222 | return 0; |
223 | } |
224 | |
225 | static int scmi_powercap_get_max_time_window_us(struct powercap_zone *pz, |
226 | int cid, u64 *time_window_us) |
227 | { |
228 | struct scmi_powercap_zone *spz = to_scmi_powercap_zone(pz); |
229 | |
230 | *time_window_us = spz->info->max_pai; |
231 | |
232 | return 0; |
233 | } |
234 | |
235 | static int scmi_powercap_get_min_time_window_us(struct powercap_zone *pz, |
236 | int cid, u64 *time_window_us) |
237 | { |
238 | struct scmi_powercap_zone *spz = to_scmi_powercap_zone(pz); |
239 | |
240 | *time_window_us = (u64)spz->info->min_pai; |
241 | |
242 | return 0; |
243 | } |
244 | |
245 | static const char *scmi_powercap_get_name(struct powercap_zone *pz, int cid) |
246 | { |
247 | return "SCMI power-cap" ; |
248 | } |
249 | |
250 | static const struct powercap_zone_constraint_ops constraint_ops = { |
251 | .set_power_limit_uw = scmi_powercap_set_power_limit_uw, |
252 | .get_power_limit_uw = scmi_powercap_get_power_limit_uw, |
253 | .set_time_window_us = scmi_powercap_set_time_window_us, |
254 | .get_time_window_us = scmi_powercap_get_time_window_us, |
255 | .get_max_power_uw = scmi_powercap_get_max_power_uw, |
256 | .get_min_power_uw = scmi_powercap_get_min_power_uw, |
257 | .get_max_time_window_us = scmi_powercap_get_max_time_window_us, |
258 | .get_min_time_window_us = scmi_powercap_get_min_time_window_us, |
259 | .get_name = scmi_powercap_get_name, |
260 | }; |
261 | |
262 | static void scmi_powercap_unregister_all_zones(struct scmi_powercap_root *pr) |
263 | { |
264 | int i; |
265 | |
266 | /* Un-register children zones first starting from the leaves */ |
267 | for (i = pr->num_zones - 1; i >= 0; i--) { |
268 | if (!list_empty(head: &pr->registered_zones[i])) { |
269 | struct scmi_powercap_zone *spz; |
270 | |
271 | list_for_each_entry(spz, &pr->registered_zones[i], node) |
272 | powercap_unregister_zone(control_type: scmi_top_pcntrl, |
273 | power_zone: &spz->zone); |
274 | } |
275 | } |
276 | } |
277 | |
278 | static inline unsigned int |
279 | scmi_powercap_get_zone_height(struct scmi_powercap_zone *spz) |
280 | { |
281 | if (spz->info->parent_id == SCMI_POWERCAP_ROOT_ZONE_ID) |
282 | return 0; |
283 | |
284 | return spz->spzones[spz->info->parent_id].height + 1; |
285 | } |
286 | |
287 | static inline struct scmi_powercap_zone * |
288 | scmi_powercap_get_parent_zone(struct scmi_powercap_zone *spz) |
289 | { |
290 | if (spz->info->parent_id == SCMI_POWERCAP_ROOT_ZONE_ID) |
291 | return NULL; |
292 | |
293 | return &spz->spzones[spz->info->parent_id]; |
294 | } |
295 | |
296 | static int scmi_powercap_register_zone(struct scmi_powercap_root *pr, |
297 | struct scmi_powercap_zone *spz, |
298 | struct scmi_powercap_zone *parent) |
299 | { |
300 | int ret = 0; |
301 | struct powercap_zone *z; |
302 | |
303 | if (spz->invalid) { |
304 | list_del(entry: &spz->node); |
305 | return -EINVAL; |
306 | } |
307 | |
308 | z = powercap_register_zone(power_zone: &spz->zone, control_type: scmi_top_pcntrl, name: spz->info->name, |
309 | parent: parent ? &parent->zone : NULL, |
310 | ops: &zone_ops, nr_constraints: 1, const_ops: &constraint_ops); |
311 | if (!IS_ERR(ptr: z)) { |
312 | spz->height = scmi_powercap_get_zone_height(spz); |
313 | spz->registered = true; |
314 | list_move(list: &spz->node, head: &pr->registered_zones[spz->height]); |
315 | dev_dbg(spz->dev, "Registered node %s - parent %s - height:%d\n" , |
316 | spz->info->name, parent ? parent->info->name : "ROOT" , |
317 | spz->height); |
318 | } else { |
319 | list_del(entry: &spz->node); |
320 | ret = PTR_ERR(ptr: z); |
321 | dev_err(spz->dev, |
322 | "Error registering node:%s - parent:%s - h:%d - ret:%d\n" , |
323 | spz->info->name, |
324 | parent ? parent->info->name : "ROOT" , |
325 | spz->height, ret); |
326 | } |
327 | |
328 | return ret; |
329 | } |
330 | |
331 | /** |
332 | * scmi_zones_register- Register SCMI powercap zones starting from parent zones |
333 | * |
334 | * @dev: A reference to the SCMI device |
335 | * @pr: A reference to the root powercap zones descriptors |
336 | * |
337 | * When registering SCMI powercap zones with the powercap framework we should |
338 | * take care to always register zones starting from the root ones and to |
339 | * deregister starting from the leaves. |
340 | * |
341 | * Unfortunately we cannot assume that the array of available SCMI powercap |
342 | * zones provided by the SCMI platform firmware is built to comply with such |
343 | * requirement. |
344 | * |
345 | * This function, given the set of SCMI powercap zones to register, takes care |
346 | * to walk the SCMI powercap zones trees up to the root registering any |
347 | * unregistered parent zone before registering the child zones; at the same |
348 | * time each registered-zone height in such a tree is accounted for and each |
349 | * zone, once registered, is stored in the @registered_zones array that is |
350 | * indexed by zone height: this way will be trivial, at unregister time, to walk |
351 | * the @registered_zones array backward and unregister all the zones starting |
352 | * from the leaves, removing children zones before parents. |
353 | * |
354 | * While doing this, we prune away any zone marked as invalid (like the ones |
355 | * sporting an SCMI abstract power scale) as long as they are positioned as |
356 | * leaves in the SCMI powercap zones hierarchy: any non-leaf invalid zone causes |
357 | * the entire process to fail since we cannot assume the correctness of an SCMI |
358 | * powercap zones hierarchy if some of the internal nodes are missing. |
359 | * |
360 | * Note that the array of SCMI powercap zones as returned by the SCMI platform |
361 | * is known to be sane, i.e. zones relationships have been validated at the |
362 | * protocol layer. |
363 | * |
364 | * Return: 0 on Success |
365 | */ |
366 | static int scmi_zones_register(struct device *dev, |
367 | struct scmi_powercap_root *pr) |
368 | { |
369 | int ret = 0; |
370 | unsigned int sp = 0, reg_zones = 0; |
371 | struct scmi_powercap_zone *spz, **zones_stack; |
372 | |
373 | zones_stack = kcalloc(n: pr->num_zones, size: sizeof(spz), GFP_KERNEL); |
374 | if (!zones_stack) |
375 | return -ENOMEM; |
376 | |
377 | spz = list_first_entry_or_null(&pr->scmi_zones, |
378 | struct scmi_powercap_zone, node); |
379 | while (spz) { |
380 | struct scmi_powercap_zone *parent; |
381 | |
382 | parent = scmi_powercap_get_parent_zone(spz); |
383 | if (parent && !parent->registered) { |
384 | zones_stack[sp++] = spz; |
385 | spz = parent; |
386 | } else { |
387 | ret = scmi_powercap_register_zone(pr, spz, parent); |
388 | if (!ret) { |
389 | reg_zones++; |
390 | } else if (sp) { |
391 | /* Failed to register a non-leaf zone. |
392 | * Bail-out. |
393 | */ |
394 | dev_err(dev, |
395 | "Failed to register non-leaf zone - ret:%d\n" , |
396 | ret); |
397 | scmi_powercap_unregister_all_zones(pr); |
398 | reg_zones = 0; |
399 | goto out; |
400 | } |
401 | /* Pick next zone to process */ |
402 | if (sp) |
403 | spz = zones_stack[--sp]; |
404 | else |
405 | spz = list_first_entry_or_null(&pr->scmi_zones, |
406 | struct scmi_powercap_zone, |
407 | node); |
408 | } |
409 | } |
410 | |
411 | out: |
412 | kfree(objp: zones_stack); |
413 | dev_info(dev, "Registered %d SCMI Powercap domains !\n" , reg_zones); |
414 | |
415 | return ret; |
416 | } |
417 | |
418 | static int scmi_powercap_probe(struct scmi_device *sdev) |
419 | { |
420 | int ret, i; |
421 | struct scmi_powercap_root *pr; |
422 | struct scmi_powercap_zone *spz; |
423 | struct scmi_protocol_handle *ph; |
424 | struct device *dev = &sdev->dev; |
425 | |
426 | if (!sdev->handle) |
427 | return -ENODEV; |
428 | |
429 | powercap_ops = sdev->handle->devm_protocol_get(sdev, |
430 | SCMI_PROTOCOL_POWERCAP, |
431 | &ph); |
432 | if (IS_ERR(ptr: powercap_ops)) |
433 | return PTR_ERR(ptr: powercap_ops); |
434 | |
435 | pr = devm_kzalloc(dev, size: sizeof(*pr), GFP_KERNEL); |
436 | if (!pr) |
437 | return -ENOMEM; |
438 | |
439 | ret = powercap_ops->num_domains_get(ph); |
440 | if (ret < 0) { |
441 | dev_err(dev, "number of powercap domains not found\n" ); |
442 | return ret; |
443 | } |
444 | pr->num_zones = ret; |
445 | |
446 | pr->spzones = devm_kcalloc(dev, n: pr->num_zones, |
447 | size: sizeof(*pr->spzones), GFP_KERNEL); |
448 | if (!pr->spzones) |
449 | return -ENOMEM; |
450 | |
451 | /* Allocate for worst possible scenario of maximum tree height. */ |
452 | pr->registered_zones = devm_kcalloc(dev, n: pr->num_zones, |
453 | size: sizeof(*pr->registered_zones), |
454 | GFP_KERNEL); |
455 | if (!pr->registered_zones) |
456 | return -ENOMEM; |
457 | |
458 | INIT_LIST_HEAD(list: &pr->scmi_zones); |
459 | |
460 | for (i = 0, spz = pr->spzones; i < pr->num_zones; i++, spz++) { |
461 | /* |
462 | * Powercap domains are validate by the protocol layer, i.e. |
463 | * when only non-NULL domains are returned here, whose |
464 | * parent_id is assured to point to another valid domain. |
465 | */ |
466 | spz->info = powercap_ops->info_get(ph, i); |
467 | |
468 | spz->dev = dev; |
469 | spz->ph = ph; |
470 | spz->spzones = pr->spzones; |
471 | INIT_LIST_HEAD(list: &spz->node); |
472 | INIT_LIST_HEAD(list: &pr->registered_zones[i]); |
473 | |
474 | list_add_tail(new: &spz->node, head: &pr->scmi_zones); |
475 | /* |
476 | * Forcibly skip powercap domains using an abstract scale. |
477 | * Note that only leaves domains can be skipped, so this could |
478 | * lead later to a global failure. |
479 | */ |
480 | if (!spz->info->powercap_scale_uw && |
481 | !spz->info->powercap_scale_mw) { |
482 | dev_warn(dev, |
483 | "Abstract power scale not supported. Skip %s.\n" , |
484 | spz->info->name); |
485 | spz->invalid = true; |
486 | continue; |
487 | } |
488 | } |
489 | |
490 | /* |
491 | * Scan array of retrieved SCMI powercap domains and register them |
492 | * recursively starting from the root domains. |
493 | */ |
494 | ret = scmi_zones_register(dev, pr); |
495 | if (ret) |
496 | return ret; |
497 | |
498 | dev_set_drvdata(dev, data: pr); |
499 | |
500 | return ret; |
501 | } |
502 | |
503 | static void scmi_powercap_remove(struct scmi_device *sdev) |
504 | { |
505 | struct device *dev = &sdev->dev; |
506 | struct scmi_powercap_root *pr = dev_get_drvdata(dev); |
507 | |
508 | scmi_powercap_unregister_all_zones(pr); |
509 | } |
510 | |
511 | static const struct scmi_device_id scmi_id_table[] = { |
512 | { SCMI_PROTOCOL_POWERCAP, "powercap" }, |
513 | { }, |
514 | }; |
515 | MODULE_DEVICE_TABLE(scmi, scmi_id_table); |
516 | |
517 | static struct scmi_driver scmi_powercap_driver = { |
518 | .name = "scmi-powercap" , |
519 | .probe = scmi_powercap_probe, |
520 | .remove = scmi_powercap_remove, |
521 | .id_table = scmi_id_table, |
522 | }; |
523 | |
524 | static int __init scmi_powercap_init(void) |
525 | { |
526 | int ret; |
527 | |
528 | scmi_top_pcntrl = powercap_register_control_type(NULL, name: "arm-scmi" , NULL); |
529 | if (IS_ERR(ptr: scmi_top_pcntrl)) |
530 | return PTR_ERR(ptr: scmi_top_pcntrl); |
531 | |
532 | ret = scmi_register(&scmi_powercap_driver); |
533 | if (ret) |
534 | powercap_unregister_control_type(instance: scmi_top_pcntrl); |
535 | |
536 | return ret; |
537 | } |
538 | module_init(scmi_powercap_init); |
539 | |
540 | static void __exit scmi_powercap_exit(void) |
541 | { |
542 | scmi_unregister(&scmi_powercap_driver); |
543 | |
544 | powercap_unregister_control_type(instance: scmi_top_pcntrl); |
545 | } |
546 | module_exit(scmi_powercap_exit); |
547 | |
548 | MODULE_AUTHOR("Cristian Marussi <cristian.marussi@arm.com>" ); |
549 | MODULE_DESCRIPTION("ARM SCMI Powercap driver" ); |
550 | MODULE_LICENSE("GPL" ); |
551 | |