xref: /linux/drivers/hwmon/acpi_power_meter.c (revision 53597deca0e38c30e6cd4ba2114fa42d2bcd85bb)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * A hwmon driver for ACPI 4.0 power meters
4  * Copyright (C) 2009 IBM
5  *
6  * Author: Darrick J. Wong <darrick.wong@oracle.com>
7  */
8 
9 #include <linux/module.h>
10 #include <linux/hwmon.h>
11 #include <linux/hwmon-sysfs.h>
12 #include <linux/jiffies.h>
13 #include <linux/mutex.h>
14 #include <linux/dmi.h>
15 #include <linux/slab.h>
16 #include <linux/kdev_t.h>
17 #include <linux/sched.h>
18 #include <linux/time.h>
19 #include <linux/err.h>
20 #include <linux/acpi.h>
21 #include <linux/platform_device.h>
22 
23 #define ACPI_POWER_METER_NAME		"power_meter"
24 #define ACPI_POWER_METER_DEVICE_NAME	"Power Meter"
25 #define ACPI_POWER_METER_CLASS		"pwr_meter_resource"
26 
27 #define NUM_SENSORS			17
28 
29 #define POWER_METER_CAN_MEASURE	(1 << 0)
30 #define POWER_METER_CAN_TRIP	(1 << 1)
31 #define POWER_METER_CAN_CAP	(1 << 2)
32 #define POWER_METER_CAN_NOTIFY	(1 << 3)
33 #define POWER_METER_IS_BATTERY	(1 << 8)
34 #define UNKNOWN_HYSTERESIS	0xFFFFFFFF
35 #define UNKNOWN_POWER		0xFFFFFFFF
36 
37 #define METER_NOTIFY_CONFIG	0x80
38 #define METER_NOTIFY_TRIP	0x81
39 #define METER_NOTIFY_CAP	0x82
40 #define METER_NOTIFY_CAPPING	0x83
41 #define METER_NOTIFY_INTERVAL	0x84
42 
43 #define POWER_AVERAGE_NAME	"power1_average"
44 #define POWER_CAP_NAME		"power1_cap"
45 #define POWER_AVG_INTERVAL_NAME	"power1_average_interval"
46 #define POWER_ALARM_NAME	"power1_alarm"
47 
48 static int cap_in_hardware;
49 static bool force_cap_on;
50 
51 static DEFINE_MUTEX(acpi_notify_lock);
52 
53 static int can_cap_in_hardware(void)
54 {
55 	return force_cap_on || cap_in_hardware;
56 }
57 
58 static const struct acpi_device_id power_meter_ids[] = {
59 	{"ACPI000D", 0},
60 	{"", 0},
61 };
62 MODULE_DEVICE_TABLE(acpi, power_meter_ids);
63 
64 struct acpi_power_meter_capabilities {
65 	u64		flags;
66 	u64		units;
67 	u64		type;
68 	u64		accuracy;
69 	u64		sampling_time;
70 	u64		min_avg_interval;
71 	u64		max_avg_interval;
72 	u64		hysteresis;
73 	u64		configurable_cap;
74 	u64		min_cap;
75 	u64		max_cap;
76 };
77 
78 struct acpi_power_meter_resource {
79 	struct acpi_device	*acpi_dev;
80 	acpi_bus_id		name;
81 	struct mutex		lock;
82 	struct device		*hwmon_dev;
83 	struct acpi_power_meter_capabilities	caps;
84 	acpi_string		model_number;
85 	acpi_string		serial_number;
86 	acpi_string		oem_info;
87 	u64		power;
88 	u64		cap;
89 	u64		avg_interval;
90 	bool		power_alarm;
91 	int			sensors_valid;
92 	unsigned long		sensors_last_updated;
93 #define POWER_METER_TRIP_AVERAGE_MIN_IDX	0
94 #define POWER_METER_TRIP_AVERAGE_MAX_IDX	1
95 	s64			trip[2];
96 	int			num_domain_devices;
97 	struct acpi_device	**domain_devices;
98 	struct kobject		*holders_dir;
99 };
100 
101 /* Averaging interval */
102 static int update_avg_interval(struct acpi_power_meter_resource *resource)
103 {
104 	unsigned long long data;
105 	acpi_status status;
106 
107 	status = acpi_evaluate_integer(resource->acpi_dev->handle, "_GAI",
108 				       NULL, &data);
109 	if (ACPI_FAILURE(status)) {
110 		acpi_evaluation_failure_warn(resource->acpi_dev->handle, "_GAI",
111 					     status);
112 		return -ENODEV;
113 	}
114 
115 	resource->avg_interval = data;
116 	return 0;
117 }
118 
119 /* Cap functions */
120 static int update_cap(struct acpi_power_meter_resource *resource)
121 {
122 	unsigned long long data;
123 	acpi_status status;
124 
125 	status = acpi_evaluate_integer(resource->acpi_dev->handle, "_GHL",
126 				       NULL, &data);
127 	if (ACPI_FAILURE(status)) {
128 		acpi_evaluation_failure_warn(resource->acpi_dev->handle, "_GHL",
129 					     status);
130 		return -ENODEV;
131 	}
132 
133 	resource->cap = data;
134 	return 0;
135 }
136 
137 /* Power meter trip points */
138 static int set_acpi_trip(struct acpi_power_meter_resource *resource)
139 {
140 	union acpi_object arg_objs[] = {
141 		{ACPI_TYPE_INTEGER},
142 		{ACPI_TYPE_INTEGER}
143 	};
144 	struct acpi_object_list args = { 2, arg_objs };
145 	unsigned long long data;
146 	acpi_status status;
147 
148 	/* Both trip levels must be set */
149 	if (resource->trip[0] < 0 || resource->trip[1] < 0)
150 		return 0;
151 
152 	/* This driver stores min, max; ACPI wants max, min. */
153 	arg_objs[0].integer.value = resource->trip[1];
154 	arg_objs[1].integer.value = resource->trip[0];
155 
156 	status = acpi_evaluate_integer(resource->acpi_dev->handle, "_PTP",
157 				       &args, &data);
158 	if (ACPI_FAILURE(status)) {
159 		acpi_evaluation_failure_warn(resource->acpi_dev->handle, "_PTP",
160 					     status);
161 		return -EINVAL;
162 	}
163 
164 	/* _PTP returns 0 on success, nonzero otherwise */
165 	if (data)
166 		return -EINVAL;
167 
168 	return 0;
169 }
170 
171 /* Power meter */
172 static int update_meter(struct acpi_power_meter_resource *resource)
173 {
174 	unsigned long long data;
175 	acpi_status status;
176 	unsigned long local_jiffies = jiffies;
177 
178 	if (time_before(local_jiffies, resource->sensors_last_updated +
179 			msecs_to_jiffies(resource->caps.sampling_time)) &&
180 			resource->sensors_valid)
181 		return 0;
182 
183 	status = acpi_evaluate_integer(resource->acpi_dev->handle, "_PMM",
184 				       NULL, &data);
185 	if (ACPI_FAILURE(status)) {
186 		acpi_evaluation_failure_warn(resource->acpi_dev->handle, "_PMM",
187 					     status);
188 		return -ENODEV;
189 	}
190 
191 	resource->power = data;
192 	resource->sensors_valid = 1;
193 	resource->sensors_last_updated = jiffies;
194 	return 0;
195 }
196 
197 /* Read power domain data */
198 static void remove_domain_devices(struct acpi_power_meter_resource *resource)
199 {
200 	int i;
201 
202 	if (!resource->num_domain_devices)
203 		return;
204 
205 	for (i = 0; i < resource->num_domain_devices; i++) {
206 		struct acpi_device *obj = resource->domain_devices[i];
207 
208 		if (!obj)
209 			continue;
210 
211 		sysfs_remove_link(resource->holders_dir,
212 				  kobject_name(&obj->dev.kobj));
213 		acpi_dev_put(obj);
214 	}
215 
216 	kfree(resource->domain_devices);
217 	kobject_put(resource->holders_dir);
218 	resource->num_domain_devices = 0;
219 }
220 
221 static int read_domain_devices(struct acpi_power_meter_resource *resource)
222 {
223 	int res = 0;
224 	int i;
225 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
226 	union acpi_object *pss;
227 	acpi_status status;
228 
229 	status = acpi_evaluate_object(resource->acpi_dev->handle, "_PMD", NULL,
230 				      &buffer);
231 	if (ACPI_FAILURE(status)) {
232 		acpi_evaluation_failure_warn(resource->acpi_dev->handle, "_PMD",
233 					     status);
234 		return -ENODEV;
235 	}
236 
237 	pss = buffer.pointer;
238 	if (!pss ||
239 	    pss->type != ACPI_TYPE_PACKAGE) {
240 		dev_err(&resource->acpi_dev->dev, ACPI_POWER_METER_NAME
241 			"Invalid _PMD data\n");
242 		res = -EFAULT;
243 		goto end;
244 	}
245 
246 	if (!pss->package.count)
247 		goto end;
248 
249 	resource->domain_devices = kzalloc_objs(struct acpi_device *,
250 						pss->package.count);
251 	if (!resource->domain_devices) {
252 		res = -ENOMEM;
253 		goto end;
254 	}
255 
256 	resource->holders_dir = kobject_create_and_add("measures",
257 						       &resource->acpi_dev->dev.kobj);
258 	if (!resource->holders_dir) {
259 		res = -ENOMEM;
260 		goto exit_free;
261 	}
262 
263 	resource->num_domain_devices = pss->package.count;
264 
265 	for (i = 0; i < pss->package.count; i++) {
266 		struct acpi_device *obj;
267 		union acpi_object *element = &pss->package.elements[i];
268 
269 		/* Refuse non-references */
270 		if (element->type != ACPI_TYPE_LOCAL_REFERENCE)
271 			continue;
272 
273 		/* Create a symlink to domain objects */
274 		obj = acpi_get_acpi_dev(element->reference.handle);
275 		resource->domain_devices[i] = obj;
276 		if (!obj)
277 			continue;
278 
279 		res = sysfs_create_link(resource->holders_dir, &obj->dev.kobj,
280 					kobject_name(&obj->dev.kobj));
281 		if (res) {
282 			acpi_dev_put(obj);
283 			resource->domain_devices[i] = NULL;
284 		}
285 	}
286 
287 	res = 0;
288 	goto end;
289 
290 exit_free:
291 	kfree(resource->domain_devices);
292 end:
293 	kfree(buffer.pointer);
294 	return res;
295 }
296 
297 static int set_trip(struct acpi_power_meter_resource *resource, u16 trip_idx,
298 		    unsigned long trip)
299 {
300 	unsigned long trip_bk;
301 	int ret;
302 
303 	trip = DIV_ROUND_CLOSEST(trip, 1000);
304 	trip_bk = resource->trip[trip_idx];
305 
306 	resource->trip[trip_idx] = trip;
307 	ret = set_acpi_trip(resource);
308 	if (ret) {
309 		dev_err(&resource->acpi_dev->dev, "set %s failed.\n",
310 			(trip_idx == POWER_METER_TRIP_AVERAGE_MIN_IDX) ?
311 			 "power1_average_min" : "power1_average_max");
312 		resource->trip[trip_idx] = trip_bk;
313 	}
314 
315 	return ret;
316 }
317 
318 static int set_cap(struct acpi_power_meter_resource *resource,
319 		   unsigned long cap)
320 {
321 	union acpi_object arg0 = { ACPI_TYPE_INTEGER };
322 	struct acpi_object_list args = { 1, &arg0 };
323 	unsigned long long data;
324 	acpi_status status;
325 
326 	cap = DIV_ROUND_CLOSEST(cap, 1000);
327 	if (cap > resource->caps.max_cap || cap < resource->caps.min_cap)
328 		return -EINVAL;
329 
330 	arg0.integer.value = cap;
331 	status = acpi_evaluate_integer(resource->acpi_dev->handle, "_SHL",
332 				       &args, &data);
333 	if (ACPI_FAILURE(status)) {
334 		acpi_evaluation_failure_warn(resource->acpi_dev->handle, "_SHL",
335 					     status);
336 		return -EINVAL;
337 	}
338 	resource->cap = cap;
339 
340 	/* _SHL returns 0 on success, nonzero otherwise */
341 	if (data)
342 		return -EINVAL;
343 
344 	return 0;
345 }
346 
347 static int set_avg_interval(struct acpi_power_meter_resource *resource,
348 			    unsigned long val)
349 {
350 	union acpi_object arg0 = { ACPI_TYPE_INTEGER };
351 	struct acpi_object_list args = { 1, &arg0 };
352 	unsigned long long data;
353 	acpi_status status;
354 
355 	if (val > resource->caps.max_avg_interval ||
356 	    val < resource->caps.min_avg_interval)
357 		return -EINVAL;
358 
359 	arg0.integer.value = val;
360 	status = acpi_evaluate_integer(resource->acpi_dev->handle, "_PAI",
361 				       &args, &data);
362 	if (ACPI_FAILURE(status)) {
363 		acpi_evaluation_failure_warn(resource->acpi_dev->handle, "_PAI",
364 					     status);
365 		return -EINVAL;
366 	}
367 	resource->avg_interval = val;
368 
369 	/* _PAI returns 0 on success, nonzero otherwise */
370 	if (data)
371 		return -EINVAL;
372 
373 	return 0;
374 }
375 
376 static int get_power_alarm_state(struct acpi_power_meter_resource *resource,
377 				 long *val)
378 {
379 	int ret;
380 
381 	ret = update_meter(resource);
382 	if (ret)
383 		return ret;
384 
385 	/* need to update cap if not to support the notification. */
386 	if (!(resource->caps.flags & POWER_METER_CAN_NOTIFY)) {
387 		ret = update_cap(resource);
388 		if (ret)
389 			return ret;
390 		resource->power_alarm = resource->power > resource->cap;
391 		*val = resource->power_alarm;
392 	} else {
393 		*val = resource->power_alarm || resource->power > resource->cap;
394 		resource->power_alarm = resource->power > resource->cap;
395 	}
396 
397 	return 0;
398 }
399 
400 static umode_t power_meter_is_visible(const void *data,
401 				      enum hwmon_sensor_types type,
402 				      u32 attr, int channel)
403 {
404 	const struct acpi_power_meter_resource *res = data;
405 
406 	if (type != hwmon_power)
407 		return 0;
408 
409 	switch (attr) {
410 	case hwmon_power_average:
411 	case hwmon_power_average_interval_min:
412 	case hwmon_power_average_interval_max:
413 		if (res->caps.flags & POWER_METER_CAN_MEASURE)
414 			return 0444;
415 		break;
416 	case hwmon_power_average_interval:
417 		if (res->caps.flags & POWER_METER_CAN_MEASURE)
418 			return 0644;
419 		break;
420 	case hwmon_power_cap_min:
421 	case hwmon_power_cap_max:
422 	case hwmon_power_alarm:
423 		if (res->caps.flags & POWER_METER_CAN_CAP && can_cap_in_hardware())
424 			return 0444;
425 		break;
426 	case hwmon_power_cap:
427 		if (res->caps.flags & POWER_METER_CAN_CAP && can_cap_in_hardware()) {
428 			if (res->caps.configurable_cap)
429 				return 0644;
430 			else
431 				return 0444;
432 		}
433 		break;
434 	default:
435 		break;
436 	}
437 
438 	return 0;
439 }
440 
441 static int power_meter_read(struct device *dev, enum hwmon_sensor_types type,
442 			    u32 attr, int channel, long *val)
443 {
444 	struct acpi_power_meter_resource *res = dev_get_drvdata(dev);
445 	int ret = 0;
446 
447 	if (type != hwmon_power)
448 		return -EINVAL;
449 
450 	guard(mutex)(&res->lock);
451 
452 	switch (attr) {
453 	case hwmon_power_average:
454 		ret = update_meter(res);
455 		if (ret)
456 			return ret;
457 		if (res->power == UNKNOWN_POWER)
458 			return -ENODATA;
459 		*val = res->power * 1000;
460 		break;
461 	case hwmon_power_average_interval_min:
462 		*val = res->caps.min_avg_interval;
463 		break;
464 	case hwmon_power_average_interval_max:
465 		*val = res->caps.max_avg_interval;
466 		break;
467 	case hwmon_power_average_interval:
468 		ret = update_avg_interval(res);
469 		if (ret)
470 			return ret;
471 		*val = (res)->avg_interval;
472 		break;
473 	case hwmon_power_cap_min:
474 		*val = res->caps.min_cap * 1000;
475 		break;
476 	case hwmon_power_cap_max:
477 		*val = res->caps.max_cap * 1000;
478 		break;
479 	case hwmon_power_alarm:
480 		ret = get_power_alarm_state(res, val);
481 		if (ret)
482 			return ret;
483 		break;
484 	case hwmon_power_cap:
485 		ret = update_cap(res);
486 		if (ret)
487 			return ret;
488 		*val = res->cap * 1000;
489 		break;
490 	default:
491 		break;
492 	}
493 
494 	return 0;
495 }
496 
497 static int power_meter_write(struct device *dev, enum hwmon_sensor_types type,
498 			     u32 attr, int channel, long val)
499 {
500 	struct acpi_power_meter_resource *res = dev_get_drvdata(dev);
501 	int ret;
502 
503 	if (type != hwmon_power)
504 		return -EINVAL;
505 
506 	guard(mutex)(&res->lock);
507 	switch (attr) {
508 	case hwmon_power_cap:
509 		ret = set_cap(res, val);
510 		break;
511 	case hwmon_power_average_interval:
512 		ret = set_avg_interval(res, val);
513 		break;
514 	default:
515 		ret = -EOPNOTSUPP;
516 	}
517 
518 	return ret;
519 }
520 
521 static const struct hwmon_channel_info * const power_meter_info[] = {
522 	HWMON_CHANNEL_INFO(power, HWMON_P_AVERAGE |
523 		HWMON_P_AVERAGE_INTERVAL | HWMON_P_AVERAGE_INTERVAL_MIN |
524 		HWMON_P_AVERAGE_INTERVAL_MAX | HWMON_P_CAP | HWMON_P_CAP_MIN |
525 		HWMON_P_CAP_MAX | HWMON_P_ALARM),
526 	NULL
527 };
528 
529 static const struct hwmon_ops power_meter_ops = {
530 	.is_visible = power_meter_is_visible,
531 	.read = power_meter_read,
532 	.write = power_meter_write,
533 };
534 
535 static const struct hwmon_chip_info power_meter_chip_info = {
536 	.ops = &power_meter_ops,
537 	.info = power_meter_info,
538 };
539 
540 static ssize_t power1_average_max_store(struct device *dev,
541 					struct device_attribute *attr,
542 					const char *buf, size_t count)
543 {
544 	struct acpi_power_meter_resource *res = dev_get_drvdata(dev);
545 	unsigned long trip;
546 	int ret;
547 
548 	ret = kstrtoul(buf, 10, &trip);
549 	if (ret)
550 		return ret;
551 
552 	mutex_lock(&res->lock);
553 	ret = set_trip(res, POWER_METER_TRIP_AVERAGE_MAX_IDX, trip);
554 	mutex_unlock(&res->lock);
555 
556 	return ret == 0 ? count : ret;
557 }
558 
559 static ssize_t power1_average_min_store(struct device *dev,
560 					struct device_attribute *attr,
561 					const char *buf, size_t count)
562 {
563 	struct acpi_power_meter_resource *res = dev_get_drvdata(dev);
564 	unsigned long trip;
565 	int ret;
566 
567 	ret = kstrtoul(buf, 10, &trip);
568 	if (ret)
569 		return ret;
570 
571 	mutex_lock(&res->lock);
572 	ret = set_trip(res, POWER_METER_TRIP_AVERAGE_MIN_IDX, trip);
573 	mutex_unlock(&res->lock);
574 
575 	return ret == 0 ? count : ret;
576 }
577 
578 static ssize_t power1_average_min_show(struct device *dev,
579 				       struct device_attribute *attr, char *buf)
580 {
581 	struct acpi_power_meter_resource *res = dev_get_drvdata(dev);
582 
583 	if (res->trip[POWER_METER_TRIP_AVERAGE_MIN_IDX] < 0)
584 		return sysfs_emit(buf, "unknown\n");
585 
586 	return sysfs_emit(buf, "%lld\n",
587 			  res->trip[POWER_METER_TRIP_AVERAGE_MIN_IDX] * 1000);
588 }
589 
590 static ssize_t power1_average_max_show(struct device *dev,
591 				       struct device_attribute *attr, char *buf)
592 {
593 	struct acpi_power_meter_resource *res = dev_get_drvdata(dev);
594 
595 	if (res->trip[POWER_METER_TRIP_AVERAGE_MAX_IDX] < 0)
596 		return sysfs_emit(buf, "unknown\n");
597 
598 	return sysfs_emit(buf, "%lld\n",
599 			  res->trip[POWER_METER_TRIP_AVERAGE_MAX_IDX] * 1000);
600 }
601 
602 static ssize_t power1_cap_hyst_show(struct device *dev,
603 				    struct device_attribute *attr, char *buf)
604 {
605 	struct acpi_power_meter_resource *res = dev_get_drvdata(dev);
606 
607 	if (res->caps.hysteresis == UNKNOWN_HYSTERESIS)
608 		return sysfs_emit(buf, "unknown\n");
609 
610 	return sysfs_emit(buf, "%llu\n", res->caps.hysteresis * 1000);
611 }
612 
613 static ssize_t power1_accuracy_show(struct device *dev,
614 				    struct device_attribute *attr,
615 				    char *buf)
616 {
617 	struct acpi_power_meter_resource *res = dev_get_drvdata(dev);
618 	unsigned int acc = res->caps.accuracy;
619 
620 	return sysfs_emit(buf, "%u.%u%%\n", acc / 1000, acc % 1000);
621 }
622 
623 static ssize_t power1_is_battery_show(struct device *dev,
624 				      struct device_attribute *attr,
625 				      char *buf)
626 {
627 	struct acpi_power_meter_resource *res = dev_get_drvdata(dev);
628 
629 	return sysfs_emit(buf, "%u\n",
630 			  res->caps.flags & POWER_METER_IS_BATTERY ? 1 : 0);
631 }
632 
633 static ssize_t power1_model_number_show(struct device *dev,
634 					struct device_attribute *attr,
635 					char *buf)
636 {
637 	struct acpi_power_meter_resource *res = dev_get_drvdata(dev);
638 
639 	return sysfs_emit(buf, "%s\n", res->model_number);
640 }
641 
642 static ssize_t power1_oem_info_show(struct device *dev,
643 				    struct device_attribute *attr,
644 				    char *buf)
645 {
646 	struct acpi_power_meter_resource *res = dev_get_drvdata(dev);
647 
648 	return sysfs_emit(buf, "%s\n", res->oem_info);
649 }
650 
651 static ssize_t power1_serial_number_show(struct device *dev,
652 					 struct device_attribute *attr,
653 					 char *buf)
654 {
655 	struct acpi_power_meter_resource *res = dev_get_drvdata(dev);
656 
657 	return sysfs_emit(buf, "%s\n", res->serial_number);
658 }
659 
660 /* depend on POWER_METER_CAN_TRIP */
661 static DEVICE_ATTR_RW(power1_average_max);
662 static DEVICE_ATTR_RW(power1_average_min);
663 
664 /* depend on POWER_METER_CAN_CAP */
665 static DEVICE_ATTR_RO(power1_cap_hyst);
666 
667 /* depend on POWER_METER_CAN_MEASURE */
668 static DEVICE_ATTR_RO(power1_accuracy);
669 static DEVICE_ATTR_RO(power1_is_battery);
670 
671 static DEVICE_ATTR_RO(power1_model_number);
672 static DEVICE_ATTR_RO(power1_oem_info);
673 static DEVICE_ATTR_RO(power1_serial_number);
674 
675 static umode_t power_extra_is_visible(struct kobject *kobj,
676 				      struct attribute *attr, int idx)
677 {
678 	struct device *dev = kobj_to_dev(kobj);
679 	struct acpi_power_meter_resource *res = dev_get_drvdata(dev);
680 
681 	if (attr == &dev_attr_power1_is_battery.attr ||
682 	    attr == &dev_attr_power1_accuracy.attr) {
683 		if ((res->caps.flags & POWER_METER_CAN_MEASURE) == 0)
684 			return 0;
685 	}
686 
687 	if (attr == &dev_attr_power1_cap_hyst.attr) {
688 		if ((res->caps.flags & POWER_METER_CAN_CAP) == 0) {
689 			return 0;
690 		} else if (!can_cap_in_hardware()) {
691 			dev_warn(&res->acpi_dev->dev,
692 				 "Ignoring unsafe software power cap!\n");
693 			return 0;
694 		}
695 	}
696 
697 	if (attr == &dev_attr_power1_average_max.attr ||
698 	    attr == &dev_attr_power1_average_min.attr) {
699 		if ((res->caps.flags & POWER_METER_CAN_TRIP) == 0)
700 			return 0;
701 	}
702 
703 	return attr->mode;
704 }
705 
706 static struct attribute *power_extra_attrs[] = {
707 	&dev_attr_power1_average_max.attr,
708 	&dev_attr_power1_average_min.attr,
709 	&dev_attr_power1_cap_hyst.attr,
710 	&dev_attr_power1_accuracy.attr,
711 	&dev_attr_power1_is_battery.attr,
712 	&dev_attr_power1_model_number.attr,
713 	&dev_attr_power1_oem_info.attr,
714 	&dev_attr_power1_serial_number.attr,
715 	NULL
716 };
717 
718 static const struct attribute_group power_extra_group = {
719 	.attrs = power_extra_attrs,
720 	.is_visible = power_extra_is_visible,
721 };
722 
723 __ATTRIBUTE_GROUPS(power_extra);
724 
725 static void free_capabilities(struct acpi_power_meter_resource *resource)
726 {
727 	acpi_string *str;
728 	int i;
729 
730 	str = &resource->model_number;
731 	for (i = 0; i < 3; i++, str++) {
732 		kfree(*str);
733 		*str = NULL;
734 	}
735 }
736 
737 static int read_capabilities(struct acpi_power_meter_resource *resource)
738 {
739 	int res = 0;
740 	int i;
741 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
742 	struct acpi_buffer state = { 0, NULL };
743 	struct acpi_buffer format = { sizeof("NNNNNNNNNNN"), "NNNNNNNNNNN" };
744 	union acpi_object *pss;
745 	acpi_string *str;
746 	acpi_status status;
747 
748 	status = acpi_evaluate_object(resource->acpi_dev->handle, "_PMC", NULL,
749 				      &buffer);
750 	if (ACPI_FAILURE(status)) {
751 		acpi_evaluation_failure_warn(resource->acpi_dev->handle, "_PMC",
752 					     status);
753 		return -ENODEV;
754 	}
755 
756 	pss = buffer.pointer;
757 	if (!pss ||
758 	    pss->type != ACPI_TYPE_PACKAGE ||
759 	    pss->package.count != 14) {
760 		dev_err(&resource->acpi_dev->dev, ACPI_POWER_METER_NAME
761 			"Invalid _PMC data\n");
762 		res = -EFAULT;
763 		goto end;
764 	}
765 
766 	/* Grab all the integer data at once */
767 	state.length = sizeof(struct acpi_power_meter_capabilities);
768 	state.pointer = &resource->caps;
769 
770 	status = acpi_extract_package(pss, &format, &state);
771 	if (ACPI_FAILURE(status)) {
772 		dev_err(&resource->acpi_dev->dev, ACPI_POWER_METER_NAME
773 			"_PMC package parsing failed: %s\n",
774 			acpi_format_exception(status));
775 		res = -EFAULT;
776 		goto end;
777 	}
778 
779 	if (resource->caps.units) {
780 		dev_err(&resource->acpi_dev->dev, ACPI_POWER_METER_NAME
781 			"Unknown units %llu.\n",
782 			resource->caps.units);
783 		res = -EINVAL;
784 		goto end;
785 	}
786 
787 	/* Grab the string data */
788 	str = &resource->model_number;
789 
790 	for (i = 11; i < 14; i++) {
791 		union acpi_object *element = &pss->package.elements[i];
792 
793 		if (element->type != ACPI_TYPE_STRING) {
794 			res = -EINVAL;
795 			goto error;
796 		}
797 
798 		*str = kmemdup_nul(element->string.pointer, element->string.length,
799 				   GFP_KERNEL);
800 		if (!*str) {
801 			res = -ENOMEM;
802 			goto error;
803 		}
804 
805 		str++;
806 	}
807 
808 	dev_info(&resource->acpi_dev->dev, "Found ACPI power meter.\n");
809 	goto end;
810 error:
811 	free_capabilities(resource);
812 end:
813 	kfree(buffer.pointer);
814 	return res;
815 }
816 
817 /* Handle ACPI event notifications */
818 static void acpi_power_meter_notify(acpi_handle handle, u32 event, void *data)
819 {
820 	struct device *dev = data;
821 	struct acpi_power_meter_resource *resource = dev_get_drvdata(dev);
822 	int res;
823 
824 	guard(mutex)(&acpi_notify_lock);
825 
826 	switch (event) {
827 	case METER_NOTIFY_CONFIG:
828 		if (!IS_ERR(resource->hwmon_dev))
829 			hwmon_device_unregister(resource->hwmon_dev);
830 
831 		mutex_lock(&resource->lock);
832 
833 		free_capabilities(resource);
834 		remove_domain_devices(resource);
835 		res = read_capabilities(resource);
836 		if (res)
837 			dev_err_once(dev, "read capabilities failed.\n");
838 		res = read_domain_devices(resource);
839 		if (res && res != -ENODEV)
840 			dev_err_once(dev, "read domain devices failed.\n");
841 
842 		mutex_unlock(&resource->lock);
843 
844 		resource->hwmon_dev =
845 			hwmon_device_register_with_info(dev,
846 							ACPI_POWER_METER_NAME,
847 							resource,
848 							&power_meter_chip_info,
849 							power_extra_groups);
850 		if (IS_ERR(resource->hwmon_dev))
851 			dev_err_once(dev, "register hwmon device failed.\n");
852 
853 		break;
854 	case METER_NOTIFY_TRIP:
855 		sysfs_notify(&dev->kobj, NULL, POWER_AVERAGE_NAME);
856 		break;
857 	case METER_NOTIFY_CAP:
858 		mutex_lock(&resource->lock);
859 		res = update_cap(resource);
860 		if (res)
861 			dev_err_once(dev, "update cap failed when capping value is changed.\n");
862 		mutex_unlock(&resource->lock);
863 		sysfs_notify(&dev->kobj, NULL, POWER_CAP_NAME);
864 		break;
865 	case METER_NOTIFY_INTERVAL:
866 		sysfs_notify(&dev->kobj, NULL, POWER_AVG_INTERVAL_NAME);
867 		break;
868 	case METER_NOTIFY_CAPPING:
869 		mutex_lock(&resource->lock);
870 		resource->power_alarm = true;
871 		mutex_unlock(&resource->lock);
872 		sysfs_notify(&dev->kobj, NULL, POWER_ALARM_NAME);
873 		dev_info(dev, "Capping in progress.\n");
874 		break;
875 	default:
876 		WARN(1, "Unexpected event %d\n", event);
877 		break;
878 	}
879 
880 	acpi_bus_generate_netlink_event(ACPI_POWER_METER_CLASS,
881 					dev_name(&resource->acpi_dev->dev),
882 					event, 0);
883 }
884 
885 static int acpi_power_meter_probe(struct platform_device *pdev)
886 {
887 	struct acpi_device *device = ACPI_COMPANION(&pdev->dev);
888 	struct acpi_power_meter_resource *resource;
889 	int res;
890 
891 	resource = kzalloc_obj(*resource);
892 	if (!resource)
893 		return -ENOMEM;
894 
895 	resource->sensors_valid = 0;
896 	resource->acpi_dev = device;
897 	mutex_init(&resource->lock);
898 	strscpy(acpi_device_name(device), ACPI_POWER_METER_DEVICE_NAME);
899 	strscpy(acpi_device_class(device), ACPI_POWER_METER_CLASS);
900 
901 	platform_set_drvdata(pdev, resource);
902 
903 #if IS_REACHABLE(CONFIG_ACPI_IPMI)
904 	/*
905 	 * On Dell systems several methods of acpi_power_meter access
906 	 * variables in IPMI region, so wait until IPMI space handler is
907 	 * installed by acpi_ipmi and also wait until SMI is selected to make
908 	 * the space handler fully functional.
909 	 */
910 	if (dmi_match(DMI_SYS_VENDOR, "Dell Inc.")) {
911 		struct acpi_device *ipi_device = acpi_dev_get_first_match_dev("IPI0001", NULL, -1);
912 
913 		if (ipi_device && acpi_wait_for_acpi_ipmi())
914 			dev_warn(&pdev->dev, "Waiting for ACPI IPMI timeout");
915 		acpi_dev_put(ipi_device);
916 	}
917 #endif
918 
919 	res = read_capabilities(resource);
920 	if (res)
921 		goto exit_free;
922 
923 	resource->trip[0] = -1;
924 	resource->trip[1] = -1;
925 
926 	/* _PMD method is optional. */
927 	res = read_domain_devices(resource);
928 	if (res && res != -ENODEV)
929 		goto exit_free_capability;
930 
931 	resource->hwmon_dev =
932 		hwmon_device_register_with_info(&pdev->dev,
933 						ACPI_POWER_METER_NAME, resource,
934 						&power_meter_chip_info,
935 						power_extra_groups);
936 	if (IS_ERR(resource->hwmon_dev)) {
937 		res = PTR_ERR(resource->hwmon_dev);
938 		goto exit_remove;
939 	}
940 
941 	res = acpi_dev_install_notify_handler(device, ACPI_DEVICE_NOTIFY,
942 					      acpi_power_meter_notify, &pdev->dev);
943 	if (res)
944 		goto exit_hwmon;
945 
946 	res = 0;
947 	goto exit;
948 
949 exit_hwmon:
950 	hwmon_device_unregister(resource->hwmon_dev);
951 exit_remove:
952 	remove_domain_devices(resource);
953 exit_free_capability:
954 	free_capabilities(resource);
955 exit_free:
956 	kfree(resource);
957 exit:
958 	return res;
959 }
960 
961 static void acpi_power_meter_remove(struct platform_device *pdev)
962 {
963 	struct acpi_power_meter_resource *resource = platform_get_drvdata(pdev);
964 
965 	acpi_dev_remove_notify_handler(resource->acpi_dev, ACPI_DEVICE_NOTIFY,
966 				       acpi_power_meter_notify);
967 
968 	if (!IS_ERR(resource->hwmon_dev))
969 		hwmon_device_unregister(resource->hwmon_dev);
970 
971 	remove_domain_devices(resource);
972 	free_capabilities(resource);
973 
974 	kfree(resource);
975 }
976 
977 static int acpi_power_meter_resume(struct device *dev)
978 {
979 	struct acpi_power_meter_resource *resource = dev_get_drvdata(dev);
980 
981 	free_capabilities(resource);
982 	read_capabilities(resource);
983 
984 	return 0;
985 }
986 
987 static DEFINE_SIMPLE_DEV_PM_OPS(acpi_power_meter_pm, NULL,
988 				acpi_power_meter_resume);
989 
990 static struct platform_driver acpi_power_meter_driver = {
991 	.probe = acpi_power_meter_probe,
992 	.remove = acpi_power_meter_remove,
993 	.driver = {
994 		.name = "acpi-power-meter",
995 		.acpi_match_table = power_meter_ids,
996 		.pm = &acpi_power_meter_pm,
997 	},
998 };
999 
1000 /* Module init/exit routines */
1001 static int __init enable_cap_knobs(const struct dmi_system_id *d)
1002 {
1003 	cap_in_hardware = 1;
1004 	return 0;
1005 }
1006 
1007 static const struct dmi_system_id pm_dmi_table[] __initconst = {
1008 	{
1009 		enable_cap_knobs, "IBM Active Energy Manager",
1010 		{
1011 			DMI_MATCH(DMI_SYS_VENDOR, "IBM")
1012 		},
1013 	},
1014 	{}
1015 };
1016 
1017 static int __init acpi_power_meter_init(void)
1018 {
1019 	int result;
1020 
1021 	if (acpi_disabled)
1022 		return -ENODEV;
1023 
1024 	dmi_check_system(pm_dmi_table);
1025 
1026 	result = platform_driver_register(&acpi_power_meter_driver);
1027 	if (result < 0)
1028 		return result;
1029 
1030 	return 0;
1031 }
1032 
1033 static void __exit acpi_power_meter_exit(void)
1034 {
1035 	platform_driver_unregister(&acpi_power_meter_driver);
1036 }
1037 
1038 MODULE_AUTHOR("Darrick J. Wong <darrick.wong@oracle.com>");
1039 MODULE_DESCRIPTION("ACPI 4.0 power meter driver");
1040 MODULE_LICENSE("GPL");
1041 
1042 module_param(force_cap_on, bool, 0644);
1043 MODULE_PARM_DESC(force_cap_on, "Enable power cap even it is unsafe to do so.");
1044 
1045 module_init(acpi_power_meter_init);
1046 module_exit(acpi_power_meter_exit);
1047