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 
22 #define ACPI_POWER_METER_NAME		"power_meter"
23 ACPI_MODULE_NAME(ACPI_POWER_METER_NAME);
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 
36 #define METER_NOTIFY_CONFIG	0x80
37 #define METER_NOTIFY_TRIP	0x81
38 #define METER_NOTIFY_CAP	0x82
39 #define METER_NOTIFY_CAPPING	0x83
40 #define METER_NOTIFY_INTERVAL	0x84
41 
42 #define POWER_AVERAGE_NAME	"power1_average"
43 #define POWER_CAP_NAME		"power1_cap"
44 #define POWER_AVG_INTERVAL_NAME	"power1_average_interval"
45 #define POWER_ALARM_NAME	"power1_alarm"
46 
47 static int cap_in_hardware;
48 static bool force_cap_on;
49 
50 static int can_cap_in_hardware(void)
51 {
52 	return force_cap_on || cap_in_hardware;
53 }
54 
55 static const struct acpi_device_id power_meter_ids[] = {
56 	{"ACPI000D", 0},
57 	{"", 0},
58 };
59 MODULE_DEVICE_TABLE(acpi, power_meter_ids);
60 
61 struct acpi_power_meter_capabilities {
62 	u64		flags;
63 	u64		units;
64 	u64		type;
65 	u64		accuracy;
66 	u64		sampling_time;
67 	u64		min_avg_interval;
68 	u64		max_avg_interval;
69 	u64		hysteresis;
70 	u64		configurable_cap;
71 	u64		min_cap;
72 	u64		max_cap;
73 };
74 
75 struct acpi_power_meter_resource {
76 	struct acpi_device	*acpi_dev;
77 	acpi_bus_id		name;
78 	struct mutex		lock;
79 	struct device		*hwmon_dev;
80 	struct acpi_power_meter_capabilities	caps;
81 	acpi_string		model_number;
82 	acpi_string		serial_number;
83 	acpi_string		oem_info;
84 	u64		power;
85 	u64		cap;
86 	u64		avg_interval;
87 	int			sensors_valid;
88 	unsigned long		sensors_last_updated;
89 	struct sensor_device_attribute	sensors[NUM_SENSORS];
90 	int			num_sensors;
91 	s64			trip[2];
92 	int			num_domain_devices;
93 	struct acpi_device	**domain_devices;
94 	struct kobject		*holders_dir;
95 };
96 
97 struct sensor_template {
98 	char *label;
99 	ssize_t (*show)(struct device *dev,
100 			struct device_attribute *devattr,
101 			char *buf);
102 	ssize_t (*set)(struct device *dev,
103 		       struct device_attribute *devattr,
104 		       const char *buf, size_t count);
105 	int index;
106 };
107 
108 /* Averaging interval */
109 static int update_avg_interval(struct acpi_power_meter_resource *resource)
110 {
111 	unsigned long long data;
112 	acpi_status status;
113 
114 	status = acpi_evaluate_integer(resource->acpi_dev->handle, "_GAI",
115 				       NULL, &data);
116 	if (ACPI_FAILURE(status)) {
117 		ACPI_EXCEPTION((AE_INFO, status, "Evaluating _GAI"));
118 		return -ENODEV;
119 	}
120 
121 	resource->avg_interval = data;
122 	return 0;
123 }
124 
125 static ssize_t show_avg_interval(struct device *dev,
126 				 struct device_attribute *devattr,
127 				 char *buf)
128 {
129 	struct acpi_device *acpi_dev = to_acpi_device(dev);
130 	struct acpi_power_meter_resource *resource = acpi_dev->driver_data;
131 
132 	mutex_lock(&resource->lock);
133 	update_avg_interval(resource);
134 	mutex_unlock(&resource->lock);
135 
136 	return sprintf(buf, "%llu\n", resource->avg_interval);
137 }
138 
139 static ssize_t set_avg_interval(struct device *dev,
140 				struct device_attribute *devattr,
141 				const char *buf, size_t count)
142 {
143 	struct acpi_device *acpi_dev = to_acpi_device(dev);
144 	struct acpi_power_meter_resource *resource = acpi_dev->driver_data;
145 	union acpi_object arg0 = { ACPI_TYPE_INTEGER };
146 	struct acpi_object_list args = { 1, &arg0 };
147 	int res;
148 	unsigned long temp;
149 	unsigned long long data;
150 	acpi_status status;
151 
152 	res = kstrtoul(buf, 10, &temp);
153 	if (res)
154 		return res;
155 
156 	if (temp > resource->caps.max_avg_interval ||
157 	    temp < resource->caps.min_avg_interval)
158 		return -EINVAL;
159 	arg0.integer.value = temp;
160 
161 	mutex_lock(&resource->lock);
162 	status = acpi_evaluate_integer(resource->acpi_dev->handle, "_PAI",
163 				       &args, &data);
164 	if (!ACPI_FAILURE(status))
165 		resource->avg_interval = temp;
166 	mutex_unlock(&resource->lock);
167 
168 	if (ACPI_FAILURE(status)) {
169 		ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PAI"));
170 		return -EINVAL;
171 	}
172 
173 	/* _PAI returns 0 on success, nonzero otherwise */
174 	if (data)
175 		return -EINVAL;
176 
177 	return count;
178 }
179 
180 /* Cap functions */
181 static int update_cap(struct acpi_power_meter_resource *resource)
182 {
183 	unsigned long long data;
184 	acpi_status status;
185 
186 	status = acpi_evaluate_integer(resource->acpi_dev->handle, "_GHL",
187 				       NULL, &data);
188 	if (ACPI_FAILURE(status)) {
189 		ACPI_EXCEPTION((AE_INFO, status, "Evaluating _GHL"));
190 		return -ENODEV;
191 	}
192 
193 	resource->cap = data;
194 	return 0;
195 }
196 
197 static ssize_t show_cap(struct device *dev,
198 			struct device_attribute *devattr,
199 			char *buf)
200 {
201 	struct acpi_device *acpi_dev = to_acpi_device(dev);
202 	struct acpi_power_meter_resource *resource = acpi_dev->driver_data;
203 
204 	mutex_lock(&resource->lock);
205 	update_cap(resource);
206 	mutex_unlock(&resource->lock);
207 
208 	return sprintf(buf, "%llu\n", resource->cap * 1000);
209 }
210 
211 static ssize_t set_cap(struct device *dev, struct device_attribute *devattr,
212 		       const char *buf, size_t count)
213 {
214 	struct acpi_device *acpi_dev = to_acpi_device(dev);
215 	struct acpi_power_meter_resource *resource = acpi_dev->driver_data;
216 	union acpi_object arg0 = { ACPI_TYPE_INTEGER };
217 	struct acpi_object_list args = { 1, &arg0 };
218 	int res;
219 	unsigned long temp;
220 	unsigned long long data;
221 	acpi_status status;
222 
223 	res = kstrtoul(buf, 10, &temp);
224 	if (res)
225 		return res;
226 
227 	temp = DIV_ROUND_CLOSEST(temp, 1000);
228 	if (temp > resource->caps.max_cap || temp < resource->caps.min_cap)
229 		return -EINVAL;
230 	arg0.integer.value = temp;
231 
232 	mutex_lock(&resource->lock);
233 	status = acpi_evaluate_integer(resource->acpi_dev->handle, "_SHL",
234 				       &args, &data);
235 	if (!ACPI_FAILURE(status))
236 		resource->cap = temp;
237 	mutex_unlock(&resource->lock);
238 
239 	if (ACPI_FAILURE(status)) {
240 		ACPI_EXCEPTION((AE_INFO, status, "Evaluating _SHL"));
241 		return -EINVAL;
242 	}
243 
244 	/* _SHL returns 0 on success, nonzero otherwise */
245 	if (data)
246 		return -EINVAL;
247 
248 	return count;
249 }
250 
251 /* Power meter trip points */
252 static int set_acpi_trip(struct acpi_power_meter_resource *resource)
253 {
254 	union acpi_object arg_objs[] = {
255 		{ACPI_TYPE_INTEGER},
256 		{ACPI_TYPE_INTEGER}
257 	};
258 	struct acpi_object_list args = { 2, arg_objs };
259 	unsigned long long data;
260 	acpi_status status;
261 
262 	/* Both trip levels must be set */
263 	if (resource->trip[0] < 0 || resource->trip[1] < 0)
264 		return 0;
265 
266 	/* This driver stores min, max; ACPI wants max, min. */
267 	arg_objs[0].integer.value = resource->trip[1];
268 	arg_objs[1].integer.value = resource->trip[0];
269 
270 	status = acpi_evaluate_integer(resource->acpi_dev->handle, "_PTP",
271 				       &args, &data);
272 	if (ACPI_FAILURE(status)) {
273 		ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PTP"));
274 		return -EINVAL;
275 	}
276 
277 	/* _PTP returns 0 on success, nonzero otherwise */
278 	if (data)
279 		return -EINVAL;
280 
281 	return 0;
282 }
283 
284 static ssize_t set_trip(struct device *dev, struct device_attribute *devattr,
285 			const char *buf, size_t count)
286 {
287 	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
288 	struct acpi_device *acpi_dev = to_acpi_device(dev);
289 	struct acpi_power_meter_resource *resource = acpi_dev->driver_data;
290 	int res;
291 	unsigned long temp;
292 
293 	res = kstrtoul(buf, 10, &temp);
294 	if (res)
295 		return res;
296 
297 	temp = DIV_ROUND_CLOSEST(temp, 1000);
298 
299 	mutex_lock(&resource->lock);
300 	resource->trip[attr->index - 7] = temp;
301 	res = set_acpi_trip(resource);
302 	mutex_unlock(&resource->lock);
303 
304 	if (res)
305 		return res;
306 
307 	return count;
308 }
309 
310 /* Power meter */
311 static int update_meter(struct acpi_power_meter_resource *resource)
312 {
313 	unsigned long long data;
314 	acpi_status status;
315 	unsigned long local_jiffies = jiffies;
316 
317 	if (time_before(local_jiffies, resource->sensors_last_updated +
318 			msecs_to_jiffies(resource->caps.sampling_time)) &&
319 			resource->sensors_valid)
320 		return 0;
321 
322 	status = acpi_evaluate_integer(resource->acpi_dev->handle, "_PMM",
323 				       NULL, &data);
324 	if (ACPI_FAILURE(status)) {
325 		ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PMM"));
326 		return -ENODEV;
327 	}
328 
329 	resource->power = data;
330 	resource->sensors_valid = 1;
331 	resource->sensors_last_updated = jiffies;
332 	return 0;
333 }
334 
335 static ssize_t show_power(struct device *dev,
336 			  struct device_attribute *devattr,
337 			  char *buf)
338 {
339 	struct acpi_device *acpi_dev = to_acpi_device(dev);
340 	struct acpi_power_meter_resource *resource = acpi_dev->driver_data;
341 
342 	mutex_lock(&resource->lock);
343 	update_meter(resource);
344 	mutex_unlock(&resource->lock);
345 
346 	return sprintf(buf, "%llu\n", resource->power * 1000);
347 }
348 
349 /* Miscellaneous */
350 static ssize_t show_str(struct device *dev,
351 			struct device_attribute *devattr,
352 			char *buf)
353 {
354 	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
355 	struct acpi_device *acpi_dev = to_acpi_device(dev);
356 	struct acpi_power_meter_resource *resource = acpi_dev->driver_data;
357 	acpi_string val;
358 
359 	switch (attr->index) {
360 	case 0:
361 		val = resource->model_number;
362 		break;
363 	case 1:
364 		val = resource->serial_number;
365 		break;
366 	case 2:
367 		val = resource->oem_info;
368 		break;
369 	default:
370 		WARN(1, "Implementation error: unexpected attribute index %d\n",
371 		     attr->index);
372 		val = "";
373 		break;
374 	}
375 
376 	return sprintf(buf, "%s\n", val);
377 }
378 
379 static ssize_t show_val(struct device *dev,
380 			struct device_attribute *devattr,
381 			char *buf)
382 {
383 	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
384 	struct acpi_device *acpi_dev = to_acpi_device(dev);
385 	struct acpi_power_meter_resource *resource = acpi_dev->driver_data;
386 	u64 val = 0;
387 
388 	switch (attr->index) {
389 	case 0:
390 		val = resource->caps.min_avg_interval;
391 		break;
392 	case 1:
393 		val = resource->caps.max_avg_interval;
394 		break;
395 	case 2:
396 		val = resource->caps.min_cap * 1000;
397 		break;
398 	case 3:
399 		val = resource->caps.max_cap * 1000;
400 		break;
401 	case 4:
402 		if (resource->caps.hysteresis == UNKNOWN_HYSTERESIS)
403 			return sprintf(buf, "unknown\n");
404 
405 		val = resource->caps.hysteresis * 1000;
406 		break;
407 	case 5:
408 		if (resource->caps.flags & POWER_METER_IS_BATTERY)
409 			val = 1;
410 		else
411 			val = 0;
412 		break;
413 	case 6:
414 		if (resource->power > resource->cap)
415 			val = 1;
416 		else
417 			val = 0;
418 		break;
419 	case 7:
420 	case 8:
421 		if (resource->trip[attr->index - 7] < 0)
422 			return sprintf(buf, "unknown\n");
423 
424 		val = resource->trip[attr->index - 7] * 1000;
425 		break;
426 	default:
427 		WARN(1, "Implementation error: unexpected attribute index %d\n",
428 		     attr->index);
429 		break;
430 	}
431 
432 	return sprintf(buf, "%llu\n", val);
433 }
434 
435 static ssize_t show_accuracy(struct device *dev,
436 			     struct device_attribute *devattr,
437 			     char *buf)
438 {
439 	struct acpi_device *acpi_dev = to_acpi_device(dev);
440 	struct acpi_power_meter_resource *resource = acpi_dev->driver_data;
441 	unsigned int acc = resource->caps.accuracy;
442 
443 	return sprintf(buf, "%u.%u%%\n", acc / 1000, acc % 1000);
444 }
445 
446 static ssize_t show_name(struct device *dev,
447 			 struct device_attribute *devattr,
448 			 char *buf)
449 {
450 	return sprintf(buf, "%s\n", ACPI_POWER_METER_NAME);
451 }
452 
453 #define RO_SENSOR_TEMPLATE(_label, _show, _index)	\
454 	{						\
455 		.label = _label,			\
456 		.show  = _show,				\
457 		.index = _index,			\
458 	}
459 
460 #define RW_SENSOR_TEMPLATE(_label, _show, _set, _index)	\
461 	{						\
462 		.label = _label,			\
463 		.show  = _show,				\
464 		.set   = _set,				\
465 		.index = _index,			\
466 	}
467 
468 /* Sensor descriptions.  If you add a sensor, update NUM_SENSORS above! */
469 static struct sensor_template meter_attrs[] = {
470 	RO_SENSOR_TEMPLATE(POWER_AVERAGE_NAME, show_power, 0),
471 	RO_SENSOR_TEMPLATE("power1_accuracy", show_accuracy, 0),
472 	RO_SENSOR_TEMPLATE("power1_average_interval_min", show_val, 0),
473 	RO_SENSOR_TEMPLATE("power1_average_interval_max", show_val, 1),
474 	RO_SENSOR_TEMPLATE("power1_is_battery", show_val, 5),
475 	RW_SENSOR_TEMPLATE(POWER_AVG_INTERVAL_NAME, show_avg_interval,
476 		set_avg_interval, 0),
477 	{},
478 };
479 
480 static struct sensor_template misc_cap_attrs[] = {
481 	RO_SENSOR_TEMPLATE("power1_cap_min", show_val, 2),
482 	RO_SENSOR_TEMPLATE("power1_cap_max", show_val, 3),
483 	RO_SENSOR_TEMPLATE("power1_cap_hyst", show_val, 4),
484 	RO_SENSOR_TEMPLATE(POWER_ALARM_NAME, show_val, 6),
485 	{},
486 };
487 
488 static struct sensor_template ro_cap_attrs[] = {
489 	RO_SENSOR_TEMPLATE(POWER_CAP_NAME, show_cap, 0),
490 	{},
491 };
492 
493 static struct sensor_template rw_cap_attrs[] = {
494 	RW_SENSOR_TEMPLATE(POWER_CAP_NAME, show_cap, set_cap, 0),
495 	{},
496 };
497 
498 static struct sensor_template trip_attrs[] = {
499 	RW_SENSOR_TEMPLATE("power1_average_min", show_val, set_trip, 7),
500 	RW_SENSOR_TEMPLATE("power1_average_max", show_val, set_trip, 8),
501 	{},
502 };
503 
504 static struct sensor_template misc_attrs[] = {
505 	RO_SENSOR_TEMPLATE("name", show_name, 0),
506 	RO_SENSOR_TEMPLATE("power1_model_number", show_str, 0),
507 	RO_SENSOR_TEMPLATE("power1_oem_info", show_str, 2),
508 	RO_SENSOR_TEMPLATE("power1_serial_number", show_str, 1),
509 	{},
510 };
511 
512 #undef RO_SENSOR_TEMPLATE
513 #undef RW_SENSOR_TEMPLATE
514 
515 /* Read power domain data */
516 static void remove_domain_devices(struct acpi_power_meter_resource *resource)
517 {
518 	int i;
519 
520 	if (!resource->num_domain_devices)
521 		return;
522 
523 	for (i = 0; i < resource->num_domain_devices; i++) {
524 		struct acpi_device *obj = resource->domain_devices[i];
525 		if (!obj)
526 			continue;
527 
528 		sysfs_remove_link(resource->holders_dir,
529 				  kobject_name(&obj->dev.kobj));
530 		put_device(&obj->dev);
531 	}
532 
533 	kfree(resource->domain_devices);
534 	kobject_put(resource->holders_dir);
535 	resource->num_domain_devices = 0;
536 }
537 
538 static int read_domain_devices(struct acpi_power_meter_resource *resource)
539 {
540 	int res = 0;
541 	int i;
542 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
543 	union acpi_object *pss;
544 	acpi_status status;
545 
546 	status = acpi_evaluate_object(resource->acpi_dev->handle, "_PMD", NULL,
547 				      &buffer);
548 	if (ACPI_FAILURE(status)) {
549 		ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PMD"));
550 		return -ENODEV;
551 	}
552 
553 	pss = buffer.pointer;
554 	if (!pss ||
555 	    pss->type != ACPI_TYPE_PACKAGE) {
556 		dev_err(&resource->acpi_dev->dev, ACPI_POWER_METER_NAME
557 			"Invalid _PMD data\n");
558 		res = -EFAULT;
559 		goto end;
560 	}
561 
562 	if (!pss->package.count)
563 		goto end;
564 
565 	resource->domain_devices = kcalloc(pss->package.count,
566 					   sizeof(struct acpi_device *),
567 					   GFP_KERNEL);
568 	if (!resource->domain_devices) {
569 		res = -ENOMEM;
570 		goto end;
571 	}
572 
573 	resource->holders_dir = kobject_create_and_add("measures",
574 					&resource->acpi_dev->dev.kobj);
575 	if (!resource->holders_dir) {
576 		res = -ENOMEM;
577 		goto exit_free;
578 	}
579 
580 	resource->num_domain_devices = pss->package.count;
581 
582 	for (i = 0; i < pss->package.count; i++) {
583 		struct acpi_device *obj;
584 		union acpi_object *element = &(pss->package.elements[i]);
585 
586 		/* Refuse non-references */
587 		if (element->type != ACPI_TYPE_LOCAL_REFERENCE)
588 			continue;
589 
590 		/* Create a symlink to domain objects */
591 		resource->domain_devices[i] = NULL;
592 		if (acpi_bus_get_device(element->reference.handle,
593 					&resource->domain_devices[i]))
594 			continue;
595 
596 		obj = resource->domain_devices[i];
597 		get_device(&obj->dev);
598 
599 		res = sysfs_create_link(resource->holders_dir, &obj->dev.kobj,
600 				      kobject_name(&obj->dev.kobj));
601 		if (res) {
602 			put_device(&obj->dev);
603 			resource->domain_devices[i] = NULL;
604 		}
605 	}
606 
607 	res = 0;
608 	goto end;
609 
610 exit_free:
611 	kfree(resource->domain_devices);
612 end:
613 	kfree(buffer.pointer);
614 	return res;
615 }
616 
617 /* Registration and deregistration */
618 static int register_attrs(struct acpi_power_meter_resource *resource,
619 			  struct sensor_template *attrs)
620 {
621 	struct device *dev = &resource->acpi_dev->dev;
622 	struct sensor_device_attribute *sensors =
623 		&resource->sensors[resource->num_sensors];
624 	int res = 0;
625 
626 	while (attrs->label) {
627 		sensors->dev_attr.attr.name = attrs->label;
628 		sensors->dev_attr.attr.mode = 0444;
629 		sensors->dev_attr.show = attrs->show;
630 		sensors->index = attrs->index;
631 
632 		if (attrs->set) {
633 			sensors->dev_attr.attr.mode |= 0200;
634 			sensors->dev_attr.store = attrs->set;
635 		}
636 
637 		sysfs_attr_init(&sensors->dev_attr.attr);
638 		res = device_create_file(dev, &sensors->dev_attr);
639 		if (res) {
640 			sensors->dev_attr.attr.name = NULL;
641 			goto error;
642 		}
643 		sensors++;
644 		resource->num_sensors++;
645 		attrs++;
646 	}
647 
648 error:
649 	return res;
650 }
651 
652 static void remove_attrs(struct acpi_power_meter_resource *resource)
653 {
654 	int i;
655 
656 	for (i = 0; i < resource->num_sensors; i++) {
657 		if (!resource->sensors[i].dev_attr.attr.name)
658 			continue;
659 		device_remove_file(&resource->acpi_dev->dev,
660 				   &resource->sensors[i].dev_attr);
661 	}
662 
663 	remove_domain_devices(resource);
664 
665 	resource->num_sensors = 0;
666 }
667 
668 static int setup_attrs(struct acpi_power_meter_resource *resource)
669 {
670 	int res = 0;
671 
672 	res = read_domain_devices(resource);
673 	if (res)
674 		return res;
675 
676 	if (resource->caps.flags & POWER_METER_CAN_MEASURE) {
677 		res = register_attrs(resource, meter_attrs);
678 		if (res)
679 			goto error;
680 	}
681 
682 	if (resource->caps.flags & POWER_METER_CAN_CAP) {
683 		if (!can_cap_in_hardware()) {
684 			dev_err(&resource->acpi_dev->dev,
685 				"Ignoring unsafe software power cap!\n");
686 			goto skip_unsafe_cap;
687 		}
688 
689 		if (resource->caps.configurable_cap)
690 			res = register_attrs(resource, rw_cap_attrs);
691 		else
692 			res = register_attrs(resource, ro_cap_attrs);
693 
694 		if (res)
695 			goto error;
696 
697 		res = register_attrs(resource, misc_cap_attrs);
698 		if (res)
699 			goto error;
700 	}
701 
702 skip_unsafe_cap:
703 	if (resource->caps.flags & POWER_METER_CAN_TRIP) {
704 		res = register_attrs(resource, trip_attrs);
705 		if (res)
706 			goto error;
707 	}
708 
709 	res = register_attrs(resource, misc_attrs);
710 	if (res)
711 		goto error;
712 
713 	return res;
714 error:
715 	remove_attrs(resource);
716 	return res;
717 }
718 
719 static void free_capabilities(struct acpi_power_meter_resource *resource)
720 {
721 	acpi_string *str;
722 	int i;
723 
724 	str = &resource->model_number;
725 	for (i = 0; i < 3; i++, str++)
726 		kfree(*str);
727 }
728 
729 static int read_capabilities(struct acpi_power_meter_resource *resource)
730 {
731 	int res = 0;
732 	int i;
733 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
734 	struct acpi_buffer state = { 0, NULL };
735 	struct acpi_buffer format = { sizeof("NNNNNNNNNNN"), "NNNNNNNNNNN" };
736 	union acpi_object *pss;
737 	acpi_string *str;
738 	acpi_status status;
739 
740 	status = acpi_evaluate_object(resource->acpi_dev->handle, "_PMC", NULL,
741 				      &buffer);
742 	if (ACPI_FAILURE(status)) {
743 		ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PMC"));
744 		return -ENODEV;
745 	}
746 
747 	pss = buffer.pointer;
748 	if (!pss ||
749 	    pss->type != ACPI_TYPE_PACKAGE ||
750 	    pss->package.count != 14) {
751 		dev_err(&resource->acpi_dev->dev, ACPI_POWER_METER_NAME
752 			"Invalid _PMC data\n");
753 		res = -EFAULT;
754 		goto end;
755 	}
756 
757 	/* Grab all the integer data at once */
758 	state.length = sizeof(struct acpi_power_meter_capabilities);
759 	state.pointer = &resource->caps;
760 
761 	status = acpi_extract_package(pss, &format, &state);
762 	if (ACPI_FAILURE(status)) {
763 		ACPI_EXCEPTION((AE_INFO, status, "Invalid data"));
764 		res = -EFAULT;
765 		goto end;
766 	}
767 
768 	if (resource->caps.units) {
769 		dev_err(&resource->acpi_dev->dev, ACPI_POWER_METER_NAME
770 			"Unknown units %llu.\n",
771 			resource->caps.units);
772 		res = -EINVAL;
773 		goto end;
774 	}
775 
776 	/* Grab the string data */
777 	str = &resource->model_number;
778 
779 	for (i = 11; i < 14; i++) {
780 		union acpi_object *element = &(pss->package.elements[i]);
781 
782 		if (element->type != ACPI_TYPE_STRING) {
783 			res = -EINVAL;
784 			goto error;
785 		}
786 
787 		*str = kcalloc(element->string.length + 1, sizeof(u8),
788 			       GFP_KERNEL);
789 		if (!*str) {
790 			res = -ENOMEM;
791 			goto error;
792 		}
793 
794 		strncpy(*str, element->string.pointer, element->string.length);
795 		str++;
796 	}
797 
798 	dev_info(&resource->acpi_dev->dev, "Found ACPI power meter.\n");
799 	goto end;
800 error:
801 	str = &resource->model_number;
802 	for (i = 0; i < 3; i++, str++)
803 		kfree(*str);
804 end:
805 	kfree(buffer.pointer);
806 	return res;
807 }
808 
809 /* Handle ACPI event notifications */
810 static void acpi_power_meter_notify(struct acpi_device *device, u32 event)
811 {
812 	struct acpi_power_meter_resource *resource;
813 	int res;
814 
815 	if (!device || !acpi_driver_data(device))
816 		return;
817 
818 	resource = acpi_driver_data(device);
819 
820 	mutex_lock(&resource->lock);
821 	switch (event) {
822 	case METER_NOTIFY_CONFIG:
823 		free_capabilities(resource);
824 		res = read_capabilities(resource);
825 		if (res)
826 			break;
827 
828 		remove_attrs(resource);
829 		setup_attrs(resource);
830 		break;
831 	case METER_NOTIFY_TRIP:
832 		sysfs_notify(&device->dev.kobj, NULL, POWER_AVERAGE_NAME);
833 		update_meter(resource);
834 		break;
835 	case METER_NOTIFY_CAP:
836 		sysfs_notify(&device->dev.kobj, NULL, POWER_CAP_NAME);
837 		update_cap(resource);
838 		break;
839 	case METER_NOTIFY_INTERVAL:
840 		sysfs_notify(&device->dev.kobj, NULL, POWER_AVG_INTERVAL_NAME);
841 		update_avg_interval(resource);
842 		break;
843 	case METER_NOTIFY_CAPPING:
844 		sysfs_notify(&device->dev.kobj, NULL, POWER_ALARM_NAME);
845 		dev_info(&device->dev, "Capping in progress.\n");
846 		break;
847 	default:
848 		WARN(1, "Unexpected event %d\n", event);
849 		break;
850 	}
851 	mutex_unlock(&resource->lock);
852 
853 	acpi_bus_generate_netlink_event(ACPI_POWER_METER_CLASS,
854 					dev_name(&device->dev), event, 0);
855 }
856 
857 static int acpi_power_meter_add(struct acpi_device *device)
858 {
859 	int res;
860 	struct acpi_power_meter_resource *resource;
861 
862 	if (!device)
863 		return -EINVAL;
864 
865 	resource = kzalloc(sizeof(struct acpi_power_meter_resource),
866 			   GFP_KERNEL);
867 	if (!resource)
868 		return -ENOMEM;
869 
870 	resource->sensors_valid = 0;
871 	resource->acpi_dev = device;
872 	mutex_init(&resource->lock);
873 	strcpy(acpi_device_name(device), ACPI_POWER_METER_DEVICE_NAME);
874 	strcpy(acpi_device_class(device), ACPI_POWER_METER_CLASS);
875 	device->driver_data = resource;
876 
877 	free_capabilities(resource);
878 	res = read_capabilities(resource);
879 	if (res)
880 		goto exit_free;
881 
882 	resource->trip[0] = resource->trip[1] = -1;
883 
884 	res = setup_attrs(resource);
885 	if (res)
886 		goto exit_free;
887 
888 	resource->hwmon_dev = hwmon_device_register(&device->dev);
889 	if (IS_ERR(resource->hwmon_dev)) {
890 		res = PTR_ERR(resource->hwmon_dev);
891 		goto exit_remove;
892 	}
893 
894 	res = 0;
895 	goto exit;
896 
897 exit_remove:
898 	remove_attrs(resource);
899 exit_free:
900 	kfree(resource);
901 exit:
902 	return res;
903 }
904 
905 static int acpi_power_meter_remove(struct acpi_device *device)
906 {
907 	struct acpi_power_meter_resource *resource;
908 
909 	if (!device || !acpi_driver_data(device))
910 		return -EINVAL;
911 
912 	resource = acpi_driver_data(device);
913 	hwmon_device_unregister(resource->hwmon_dev);
914 
915 	free_capabilities(resource);
916 	remove_attrs(resource);
917 
918 	kfree(resource);
919 	return 0;
920 }
921 
922 #ifdef CONFIG_PM_SLEEP
923 
924 static int acpi_power_meter_resume(struct device *dev)
925 {
926 	struct acpi_power_meter_resource *resource;
927 
928 	if (!dev)
929 		return -EINVAL;
930 
931 	resource = acpi_driver_data(to_acpi_device(dev));
932 	if (!resource)
933 		return -EINVAL;
934 
935 	free_capabilities(resource);
936 	read_capabilities(resource);
937 
938 	return 0;
939 }
940 
941 #endif /* CONFIG_PM_SLEEP */
942 
943 static SIMPLE_DEV_PM_OPS(acpi_power_meter_pm, NULL, acpi_power_meter_resume);
944 
945 static struct acpi_driver acpi_power_meter_driver = {
946 	.name = "power_meter",
947 	.class = ACPI_POWER_METER_CLASS,
948 	.ids = power_meter_ids,
949 	.ops = {
950 		.add = acpi_power_meter_add,
951 		.remove = acpi_power_meter_remove,
952 		.notify = acpi_power_meter_notify,
953 		},
954 	.drv.pm = &acpi_power_meter_pm,
955 };
956 
957 /* Module init/exit routines */
958 static int __init enable_cap_knobs(const struct dmi_system_id *d)
959 {
960 	cap_in_hardware = 1;
961 	return 0;
962 }
963 
964 static const struct dmi_system_id pm_dmi_table[] __initconst = {
965 	{
966 		enable_cap_knobs, "IBM Active Energy Manager",
967 		{
968 			DMI_MATCH(DMI_SYS_VENDOR, "IBM")
969 		},
970 	},
971 	{}
972 };
973 
974 static int __init acpi_power_meter_init(void)
975 {
976 	int result;
977 
978 	if (acpi_disabled)
979 		return -ENODEV;
980 
981 	dmi_check_system(pm_dmi_table);
982 
983 	result = acpi_bus_register_driver(&acpi_power_meter_driver);
984 	if (result < 0)
985 		return result;
986 
987 	return 0;
988 }
989 
990 static void __exit acpi_power_meter_exit(void)
991 {
992 	acpi_bus_unregister_driver(&acpi_power_meter_driver);
993 }
994 
995 MODULE_AUTHOR("Darrick J. Wong <darrick.wong@oracle.com>");
996 MODULE_DESCRIPTION("ACPI 4.0 power meter driver");
997 MODULE_LICENSE("GPL");
998 
999 module_param(force_cap_on, bool, 0644);
1000 MODULE_PARM_DESC(force_cap_on, "Enable power cap even it is unsafe to do so.");
1001 
1002 module_init(acpi_power_meter_init);
1003 module_exit(acpi_power_meter_exit);
1004