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 #define ACPI_POWER_METER_DEVICE_NAME	"Power Meter"
24 #define ACPI_POWER_METER_CLASS		"pwr_meter_resource"
25 
26 #define NUM_SENSORS			17
27 
28 #define POWER_METER_CAN_MEASURE	(1 << 0)
29 #define POWER_METER_CAN_TRIP	(1 << 1)
30 #define POWER_METER_CAN_CAP	(1 << 2)
31 #define POWER_METER_CAN_NOTIFY	(1 << 3)
32 #define POWER_METER_IS_BATTERY	(1 << 8)
33 #define UNKNOWN_HYSTERESIS	0xFFFFFFFF
34 #define UNKNOWN_POWER		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_evaluation_failure_warn(resource->acpi_dev->handle, "_GAI",
118 					     status);
119 		return -ENODEV;
120 	}
121 
122 	resource->avg_interval = data;
123 	return 0;
124 }
125 
126 static ssize_t show_avg_interval(struct device *dev,
127 				 struct device_attribute *devattr,
128 				 char *buf)
129 {
130 	struct acpi_device *acpi_dev = to_acpi_device(dev);
131 	struct acpi_power_meter_resource *resource = acpi_dev->driver_data;
132 
133 	mutex_lock(&resource->lock);
134 	update_avg_interval(resource);
135 	mutex_unlock(&resource->lock);
136 
137 	return sprintf(buf, "%llu\n", resource->avg_interval);
138 }
139 
140 static ssize_t set_avg_interval(struct device *dev,
141 				struct device_attribute *devattr,
142 				const char *buf, size_t count)
143 {
144 	struct acpi_device *acpi_dev = to_acpi_device(dev);
145 	struct acpi_power_meter_resource *resource = acpi_dev->driver_data;
146 	union acpi_object arg0 = { ACPI_TYPE_INTEGER };
147 	struct acpi_object_list args = { 1, &arg0 };
148 	int res;
149 	unsigned long temp;
150 	unsigned long long data;
151 	acpi_status status;
152 
153 	res = kstrtoul(buf, 10, &temp);
154 	if (res)
155 		return res;
156 
157 	if (temp > resource->caps.max_avg_interval ||
158 	    temp < resource->caps.min_avg_interval)
159 		return -EINVAL;
160 	arg0.integer.value = temp;
161 
162 	mutex_lock(&resource->lock);
163 	status = acpi_evaluate_integer(resource->acpi_dev->handle, "_PAI",
164 				       &args, &data);
165 	if (ACPI_SUCCESS(status))
166 		resource->avg_interval = temp;
167 	mutex_unlock(&resource->lock);
168 
169 	if (ACPI_FAILURE(status)) {
170 		acpi_evaluation_failure_warn(resource->acpi_dev->handle, "_PAI",
171 					     status);
172 		return -EINVAL;
173 	}
174 
175 	/* _PAI returns 0 on success, nonzero otherwise */
176 	if (data)
177 		return -EINVAL;
178 
179 	return count;
180 }
181 
182 /* Cap functions */
183 static int update_cap(struct acpi_power_meter_resource *resource)
184 {
185 	unsigned long long data;
186 	acpi_status status;
187 
188 	status = acpi_evaluate_integer(resource->acpi_dev->handle, "_GHL",
189 				       NULL, &data);
190 	if (ACPI_FAILURE(status)) {
191 		acpi_evaluation_failure_warn(resource->acpi_dev->handle, "_GHL",
192 					     status);
193 		return -ENODEV;
194 	}
195 
196 	resource->cap = data;
197 	return 0;
198 }
199 
200 static ssize_t show_cap(struct device *dev,
201 			struct device_attribute *devattr,
202 			char *buf)
203 {
204 	struct acpi_device *acpi_dev = to_acpi_device(dev);
205 	struct acpi_power_meter_resource *resource = acpi_dev->driver_data;
206 
207 	mutex_lock(&resource->lock);
208 	update_cap(resource);
209 	mutex_unlock(&resource->lock);
210 
211 	return sprintf(buf, "%llu\n", resource->cap * 1000);
212 }
213 
214 static ssize_t set_cap(struct device *dev, struct device_attribute *devattr,
215 		       const char *buf, size_t count)
216 {
217 	struct acpi_device *acpi_dev = to_acpi_device(dev);
218 	struct acpi_power_meter_resource *resource = acpi_dev->driver_data;
219 	union acpi_object arg0 = { ACPI_TYPE_INTEGER };
220 	struct acpi_object_list args = { 1, &arg0 };
221 	int res;
222 	unsigned long temp;
223 	unsigned long long data;
224 	acpi_status status;
225 
226 	res = kstrtoul(buf, 10, &temp);
227 	if (res)
228 		return res;
229 
230 	temp = DIV_ROUND_CLOSEST(temp, 1000);
231 	if (temp > resource->caps.max_cap || temp < resource->caps.min_cap)
232 		return -EINVAL;
233 	arg0.integer.value = temp;
234 
235 	mutex_lock(&resource->lock);
236 	status = acpi_evaluate_integer(resource->acpi_dev->handle, "_SHL",
237 				       &args, &data);
238 	if (ACPI_SUCCESS(status))
239 		resource->cap = temp;
240 	mutex_unlock(&resource->lock);
241 
242 	if (ACPI_FAILURE(status)) {
243 		acpi_evaluation_failure_warn(resource->acpi_dev->handle, "_SHL",
244 					     status);
245 		return -EINVAL;
246 	}
247 
248 	/* _SHL returns 0 on success, nonzero otherwise */
249 	if (data)
250 		return -EINVAL;
251 
252 	return count;
253 }
254 
255 /* Power meter trip points */
256 static int set_acpi_trip(struct acpi_power_meter_resource *resource)
257 {
258 	union acpi_object arg_objs[] = {
259 		{ACPI_TYPE_INTEGER},
260 		{ACPI_TYPE_INTEGER}
261 	};
262 	struct acpi_object_list args = { 2, arg_objs };
263 	unsigned long long data;
264 	acpi_status status;
265 
266 	/* Both trip levels must be set */
267 	if (resource->trip[0] < 0 || resource->trip[1] < 0)
268 		return 0;
269 
270 	/* This driver stores min, max; ACPI wants max, min. */
271 	arg_objs[0].integer.value = resource->trip[1];
272 	arg_objs[1].integer.value = resource->trip[0];
273 
274 	status = acpi_evaluate_integer(resource->acpi_dev->handle, "_PTP",
275 				       &args, &data);
276 	if (ACPI_FAILURE(status)) {
277 		acpi_evaluation_failure_warn(resource->acpi_dev->handle, "_PTP",
278 					     status);
279 		return -EINVAL;
280 	}
281 
282 	/* _PTP returns 0 on success, nonzero otherwise */
283 	if (data)
284 		return -EINVAL;
285 
286 	return 0;
287 }
288 
289 static ssize_t set_trip(struct device *dev, struct device_attribute *devattr,
290 			const char *buf, size_t count)
291 {
292 	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
293 	struct acpi_device *acpi_dev = to_acpi_device(dev);
294 	struct acpi_power_meter_resource *resource = acpi_dev->driver_data;
295 	int res;
296 	unsigned long temp;
297 
298 	res = kstrtoul(buf, 10, &temp);
299 	if (res)
300 		return res;
301 
302 	temp = DIV_ROUND_CLOSEST(temp, 1000);
303 
304 	mutex_lock(&resource->lock);
305 	resource->trip[attr->index - 7] = temp;
306 	res = set_acpi_trip(resource);
307 	mutex_unlock(&resource->lock);
308 
309 	if (res)
310 		return res;
311 
312 	return count;
313 }
314 
315 /* Power meter */
316 static int update_meter(struct acpi_power_meter_resource *resource)
317 {
318 	unsigned long long data;
319 	acpi_status status;
320 	unsigned long local_jiffies = jiffies;
321 
322 	if (time_before(local_jiffies, resource->sensors_last_updated +
323 			msecs_to_jiffies(resource->caps.sampling_time)) &&
324 			resource->sensors_valid)
325 		return 0;
326 
327 	status = acpi_evaluate_integer(resource->acpi_dev->handle, "_PMM",
328 				       NULL, &data);
329 	if (ACPI_FAILURE(status)) {
330 		acpi_evaluation_failure_warn(resource->acpi_dev->handle, "_PMM",
331 					     status);
332 		return -ENODEV;
333 	}
334 
335 	resource->power = data;
336 	resource->sensors_valid = 1;
337 	resource->sensors_last_updated = jiffies;
338 	return 0;
339 }
340 
341 static ssize_t show_power(struct device *dev,
342 			  struct device_attribute *devattr,
343 			  char *buf)
344 {
345 	struct acpi_device *acpi_dev = to_acpi_device(dev);
346 	struct acpi_power_meter_resource *resource = acpi_dev->driver_data;
347 
348 	mutex_lock(&resource->lock);
349 	update_meter(resource);
350 	mutex_unlock(&resource->lock);
351 
352 	if (resource->power == UNKNOWN_POWER)
353 		return -ENODATA;
354 
355 	return sprintf(buf, "%llu\n", resource->power * 1000);
356 }
357 
358 /* Miscellaneous */
359 static ssize_t show_str(struct device *dev,
360 			struct device_attribute *devattr,
361 			char *buf)
362 {
363 	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
364 	struct acpi_device *acpi_dev = to_acpi_device(dev);
365 	struct acpi_power_meter_resource *resource = acpi_dev->driver_data;
366 	acpi_string val;
367 	int ret;
368 
369 	mutex_lock(&resource->lock);
370 	switch (attr->index) {
371 	case 0:
372 		val = resource->model_number;
373 		break;
374 	case 1:
375 		val = resource->serial_number;
376 		break;
377 	case 2:
378 		val = resource->oem_info;
379 		break;
380 	default:
381 		WARN(1, "Implementation error: unexpected attribute index %d\n",
382 		     attr->index);
383 		val = "";
384 		break;
385 	}
386 	ret = sprintf(buf, "%s\n", val);
387 	mutex_unlock(&resource->lock);
388 	return ret;
389 }
390 
391 static ssize_t show_val(struct device *dev,
392 			struct device_attribute *devattr,
393 			char *buf)
394 {
395 	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
396 	struct acpi_device *acpi_dev = to_acpi_device(dev);
397 	struct acpi_power_meter_resource *resource = acpi_dev->driver_data;
398 	u64 val = 0;
399 
400 	switch (attr->index) {
401 	case 0:
402 		val = resource->caps.min_avg_interval;
403 		break;
404 	case 1:
405 		val = resource->caps.max_avg_interval;
406 		break;
407 	case 2:
408 		val = resource->caps.min_cap * 1000;
409 		break;
410 	case 3:
411 		val = resource->caps.max_cap * 1000;
412 		break;
413 	case 4:
414 		if (resource->caps.hysteresis == UNKNOWN_HYSTERESIS)
415 			return sprintf(buf, "unknown\n");
416 
417 		val = resource->caps.hysteresis * 1000;
418 		break;
419 	case 5:
420 		if (resource->caps.flags & POWER_METER_IS_BATTERY)
421 			val = 1;
422 		else
423 			val = 0;
424 		break;
425 	case 6:
426 		if (resource->power > resource->cap)
427 			val = 1;
428 		else
429 			val = 0;
430 		break;
431 	case 7:
432 	case 8:
433 		if (resource->trip[attr->index - 7] < 0)
434 			return sprintf(buf, "unknown\n");
435 
436 		val = resource->trip[attr->index - 7] * 1000;
437 		break;
438 	default:
439 		WARN(1, "Implementation error: unexpected attribute index %d\n",
440 		     attr->index);
441 		break;
442 	}
443 
444 	return sprintf(buf, "%llu\n", val);
445 }
446 
447 static ssize_t show_accuracy(struct device *dev,
448 			     struct device_attribute *devattr,
449 			     char *buf)
450 {
451 	struct acpi_device *acpi_dev = to_acpi_device(dev);
452 	struct acpi_power_meter_resource *resource = acpi_dev->driver_data;
453 	unsigned int acc = resource->caps.accuracy;
454 
455 	return sprintf(buf, "%u.%u%%\n", acc / 1000, acc % 1000);
456 }
457 
458 static ssize_t show_name(struct device *dev,
459 			 struct device_attribute *devattr,
460 			 char *buf)
461 {
462 	return sprintf(buf, "%s\n", ACPI_POWER_METER_NAME);
463 }
464 
465 #define RO_SENSOR_TEMPLATE(_label, _show, _index)	\
466 	{						\
467 		.label = _label,			\
468 		.show  = _show,				\
469 		.index = _index,			\
470 	}
471 
472 #define RW_SENSOR_TEMPLATE(_label, _show, _set, _index)	\
473 	{						\
474 		.label = _label,			\
475 		.show  = _show,				\
476 		.set   = _set,				\
477 		.index = _index,			\
478 	}
479 
480 /* Sensor descriptions.  If you add a sensor, update NUM_SENSORS above! */
481 static struct sensor_template meter_attrs[] = {
482 	RO_SENSOR_TEMPLATE(POWER_AVERAGE_NAME, show_power, 0),
483 	RO_SENSOR_TEMPLATE("power1_accuracy", show_accuracy, 0),
484 	RO_SENSOR_TEMPLATE("power1_average_interval_min", show_val, 0),
485 	RO_SENSOR_TEMPLATE("power1_average_interval_max", show_val, 1),
486 	RO_SENSOR_TEMPLATE("power1_is_battery", show_val, 5),
487 	RW_SENSOR_TEMPLATE(POWER_AVG_INTERVAL_NAME, show_avg_interval,
488 			   set_avg_interval, 0),
489 	{},
490 };
491 
492 static struct sensor_template misc_cap_attrs[] = {
493 	RO_SENSOR_TEMPLATE("power1_cap_min", show_val, 2),
494 	RO_SENSOR_TEMPLATE("power1_cap_max", show_val, 3),
495 	RO_SENSOR_TEMPLATE("power1_cap_hyst", show_val, 4),
496 	RO_SENSOR_TEMPLATE(POWER_ALARM_NAME, show_val, 6),
497 	{},
498 };
499 
500 static struct sensor_template ro_cap_attrs[] = {
501 	RO_SENSOR_TEMPLATE(POWER_CAP_NAME, show_cap, 0),
502 	{},
503 };
504 
505 static struct sensor_template rw_cap_attrs[] = {
506 	RW_SENSOR_TEMPLATE(POWER_CAP_NAME, show_cap, set_cap, 0),
507 	{},
508 };
509 
510 static struct sensor_template trip_attrs[] = {
511 	RW_SENSOR_TEMPLATE("power1_average_min", show_val, set_trip, 7),
512 	RW_SENSOR_TEMPLATE("power1_average_max", show_val, set_trip, 8),
513 	{},
514 };
515 
516 static struct sensor_template misc_attrs[] = {
517 	RO_SENSOR_TEMPLATE("name", show_name, 0),
518 	RO_SENSOR_TEMPLATE("power1_model_number", show_str, 0),
519 	RO_SENSOR_TEMPLATE("power1_oem_info", show_str, 2),
520 	RO_SENSOR_TEMPLATE("power1_serial_number", show_str, 1),
521 	{},
522 };
523 
524 #undef RO_SENSOR_TEMPLATE
525 #undef RW_SENSOR_TEMPLATE
526 
527 /* Read power domain data */
528 static void remove_domain_devices(struct acpi_power_meter_resource *resource)
529 {
530 	int i;
531 
532 	if (!resource->num_domain_devices)
533 		return;
534 
535 	for (i = 0; i < resource->num_domain_devices; i++) {
536 		struct acpi_device *obj = resource->domain_devices[i];
537 
538 		if (!obj)
539 			continue;
540 
541 		sysfs_remove_link(resource->holders_dir,
542 				  kobject_name(&obj->dev.kobj));
543 		acpi_dev_put(obj);
544 	}
545 
546 	kfree(resource->domain_devices);
547 	kobject_put(resource->holders_dir);
548 	resource->num_domain_devices = 0;
549 }
550 
551 static int read_domain_devices(struct acpi_power_meter_resource *resource)
552 {
553 	int res = 0;
554 	int i;
555 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
556 	union acpi_object *pss;
557 	acpi_status status;
558 
559 	status = acpi_evaluate_object(resource->acpi_dev->handle, "_PMD", NULL,
560 				      &buffer);
561 	if (ACPI_FAILURE(status)) {
562 		acpi_evaluation_failure_warn(resource->acpi_dev->handle, "_PMD",
563 					     status);
564 		return -ENODEV;
565 	}
566 
567 	pss = buffer.pointer;
568 	if (!pss ||
569 	    pss->type != ACPI_TYPE_PACKAGE) {
570 		dev_err(&resource->acpi_dev->dev, ACPI_POWER_METER_NAME
571 			"Invalid _PMD data\n");
572 		res = -EFAULT;
573 		goto end;
574 	}
575 
576 	if (!pss->package.count)
577 		goto end;
578 
579 	resource->domain_devices = kcalloc(pss->package.count,
580 					   sizeof(struct acpi_device *),
581 					   GFP_KERNEL);
582 	if (!resource->domain_devices) {
583 		res = -ENOMEM;
584 		goto end;
585 	}
586 
587 	resource->holders_dir = kobject_create_and_add("measures",
588 						       &resource->acpi_dev->dev.kobj);
589 	if (!resource->holders_dir) {
590 		res = -ENOMEM;
591 		goto exit_free;
592 	}
593 
594 	resource->num_domain_devices = pss->package.count;
595 
596 	for (i = 0; i < pss->package.count; i++) {
597 		struct acpi_device *obj;
598 		union acpi_object *element = &pss->package.elements[i];
599 
600 		/* Refuse non-references */
601 		if (element->type != ACPI_TYPE_LOCAL_REFERENCE)
602 			continue;
603 
604 		/* Create a symlink to domain objects */
605 		obj = acpi_get_acpi_dev(element->reference.handle);
606 		resource->domain_devices[i] = obj;
607 		if (!obj)
608 			continue;
609 
610 		res = sysfs_create_link(resource->holders_dir, &obj->dev.kobj,
611 					kobject_name(&obj->dev.kobj));
612 		if (res) {
613 			acpi_dev_put(obj);
614 			resource->domain_devices[i] = NULL;
615 		}
616 	}
617 
618 	res = 0;
619 	goto end;
620 
621 exit_free:
622 	kfree(resource->domain_devices);
623 end:
624 	kfree(buffer.pointer);
625 	return res;
626 }
627 
628 /* Registration and deregistration */
629 static int register_attrs(struct acpi_power_meter_resource *resource,
630 			  struct sensor_template *attrs)
631 {
632 	struct device *dev = &resource->acpi_dev->dev;
633 	struct sensor_device_attribute *sensors =
634 		&resource->sensors[resource->num_sensors];
635 	int res = 0;
636 
637 	while (attrs->label) {
638 		sensors->dev_attr.attr.name = attrs->label;
639 		sensors->dev_attr.attr.mode = 0444;
640 		sensors->dev_attr.show = attrs->show;
641 		sensors->index = attrs->index;
642 
643 		if (attrs->set) {
644 			sensors->dev_attr.attr.mode |= 0200;
645 			sensors->dev_attr.store = attrs->set;
646 		}
647 
648 		sysfs_attr_init(&sensors->dev_attr.attr);
649 		res = device_create_file(dev, &sensors->dev_attr);
650 		if (res) {
651 			sensors->dev_attr.attr.name = NULL;
652 			goto error;
653 		}
654 		sensors++;
655 		resource->num_sensors++;
656 		attrs++;
657 	}
658 
659 error:
660 	return res;
661 }
662 
663 static void remove_attrs(struct acpi_power_meter_resource *resource)
664 {
665 	int i;
666 
667 	for (i = 0; i < resource->num_sensors; i++) {
668 		if (!resource->sensors[i].dev_attr.attr.name)
669 			continue;
670 		device_remove_file(&resource->acpi_dev->dev,
671 				   &resource->sensors[i].dev_attr);
672 	}
673 
674 	remove_domain_devices(resource);
675 
676 	resource->num_sensors = 0;
677 }
678 
679 static int setup_attrs(struct acpi_power_meter_resource *resource)
680 {
681 	int res = 0;
682 
683 	res = read_domain_devices(resource);
684 	if (res)
685 		return res;
686 
687 	if (resource->caps.flags & POWER_METER_CAN_MEASURE) {
688 		res = register_attrs(resource, meter_attrs);
689 		if (res)
690 			goto error;
691 	}
692 
693 	if (resource->caps.flags & POWER_METER_CAN_CAP) {
694 		if (!can_cap_in_hardware()) {
695 			dev_warn(&resource->acpi_dev->dev,
696 				 "Ignoring unsafe software power cap!\n");
697 			goto skip_unsafe_cap;
698 		}
699 
700 		if (resource->caps.configurable_cap)
701 			res = register_attrs(resource, rw_cap_attrs);
702 		else
703 			res = register_attrs(resource, ro_cap_attrs);
704 
705 		if (res)
706 			goto error;
707 
708 		res = register_attrs(resource, misc_cap_attrs);
709 		if (res)
710 			goto error;
711 	}
712 
713 skip_unsafe_cap:
714 	if (resource->caps.flags & POWER_METER_CAN_TRIP) {
715 		res = register_attrs(resource, trip_attrs);
716 		if (res)
717 			goto error;
718 	}
719 
720 	res = register_attrs(resource, misc_attrs);
721 	if (res)
722 		goto error;
723 
724 	return res;
725 error:
726 	remove_attrs(resource);
727 	return res;
728 }
729 
730 static void free_capabilities(struct acpi_power_meter_resource *resource)
731 {
732 	acpi_string *str;
733 	int i;
734 
735 	str = &resource->model_number;
736 	for (i = 0; i < 3; i++, str++) {
737 		kfree(*str);
738 		*str = NULL;
739 	}
740 }
741 
742 static int read_capabilities(struct acpi_power_meter_resource *resource)
743 {
744 	int res = 0;
745 	int i;
746 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
747 	struct acpi_buffer state = { 0, NULL };
748 	struct acpi_buffer format = { sizeof("NNNNNNNNNNN"), "NNNNNNNNNNN" };
749 	union acpi_object *pss;
750 	acpi_string *str;
751 	acpi_status status;
752 
753 	status = acpi_evaluate_object(resource->acpi_dev->handle, "_PMC", NULL,
754 				      &buffer);
755 	if (ACPI_FAILURE(status)) {
756 		acpi_evaluation_failure_warn(resource->acpi_dev->handle, "_PMC",
757 					     status);
758 		return -ENODEV;
759 	}
760 
761 	pss = buffer.pointer;
762 	if (!pss ||
763 	    pss->type != ACPI_TYPE_PACKAGE ||
764 	    pss->package.count != 14) {
765 		dev_err(&resource->acpi_dev->dev, ACPI_POWER_METER_NAME
766 			"Invalid _PMC data\n");
767 		res = -EFAULT;
768 		goto end;
769 	}
770 
771 	/* Grab all the integer data at once */
772 	state.length = sizeof(struct acpi_power_meter_capabilities);
773 	state.pointer = &resource->caps;
774 
775 	status = acpi_extract_package(pss, &format, &state);
776 	if (ACPI_FAILURE(status)) {
777 		dev_err(&resource->acpi_dev->dev, ACPI_POWER_METER_NAME
778 			"_PMC package parsing failed: %s\n",
779 			acpi_format_exception(status));
780 		res = -EFAULT;
781 		goto end;
782 	}
783 
784 	if (resource->caps.units) {
785 		dev_err(&resource->acpi_dev->dev, ACPI_POWER_METER_NAME
786 			"Unknown units %llu.\n",
787 			resource->caps.units);
788 		res = -EINVAL;
789 		goto end;
790 	}
791 
792 	/* Grab the string data */
793 	str = &resource->model_number;
794 
795 	for (i = 11; i < 14; i++) {
796 		union acpi_object *element = &pss->package.elements[i];
797 
798 		if (element->type != ACPI_TYPE_STRING) {
799 			res = -EINVAL;
800 			goto error;
801 		}
802 
803 		*str = kcalloc(element->string.length + 1, sizeof(u8),
804 			       GFP_KERNEL);
805 		if (!*str) {
806 			res = -ENOMEM;
807 			goto error;
808 		}
809 
810 		strncpy(*str, element->string.pointer, element->string.length);
811 		str++;
812 	}
813 
814 	dev_info(&resource->acpi_dev->dev, "Found ACPI power meter.\n");
815 	goto end;
816 error:
817 	free_capabilities(resource);
818 end:
819 	kfree(buffer.pointer);
820 	return res;
821 }
822 
823 /* Handle ACPI event notifications */
824 static void acpi_power_meter_notify(struct acpi_device *device, u32 event)
825 {
826 	struct acpi_power_meter_resource *resource;
827 	int res;
828 
829 	if (!device || !acpi_driver_data(device))
830 		return;
831 
832 	resource = acpi_driver_data(device);
833 
834 	switch (event) {
835 	case METER_NOTIFY_CONFIG:
836 		mutex_lock(&resource->lock);
837 		free_capabilities(resource);
838 		res = read_capabilities(resource);
839 		mutex_unlock(&resource->lock);
840 		if (res)
841 			break;
842 
843 		remove_attrs(resource);
844 		setup_attrs(resource);
845 		break;
846 	case METER_NOTIFY_TRIP:
847 		sysfs_notify(&device->dev.kobj, NULL, POWER_AVERAGE_NAME);
848 		break;
849 	case METER_NOTIFY_CAP:
850 		sysfs_notify(&device->dev.kobj, NULL, POWER_CAP_NAME);
851 		break;
852 	case METER_NOTIFY_INTERVAL:
853 		sysfs_notify(&device->dev.kobj, NULL, POWER_AVG_INTERVAL_NAME);
854 		break;
855 	case METER_NOTIFY_CAPPING:
856 		sysfs_notify(&device->dev.kobj, NULL, POWER_ALARM_NAME);
857 		dev_info(&device->dev, "Capping in progress.\n");
858 		break;
859 	default:
860 		WARN(1, "Unexpected event %d\n", event);
861 		break;
862 	}
863 
864 	acpi_bus_generate_netlink_event(ACPI_POWER_METER_CLASS,
865 					dev_name(&device->dev), event, 0);
866 }
867 
868 static int acpi_power_meter_add(struct acpi_device *device)
869 {
870 	int res;
871 	struct acpi_power_meter_resource *resource;
872 
873 	if (!device)
874 		return -EINVAL;
875 
876 	resource = kzalloc(sizeof(*resource), GFP_KERNEL);
877 	if (!resource)
878 		return -ENOMEM;
879 
880 	resource->sensors_valid = 0;
881 	resource->acpi_dev = device;
882 	mutex_init(&resource->lock);
883 	strcpy(acpi_device_name(device), ACPI_POWER_METER_DEVICE_NAME);
884 	strcpy(acpi_device_class(device), ACPI_POWER_METER_CLASS);
885 	device->driver_data = resource;
886 
887 	res = read_capabilities(resource);
888 	if (res)
889 		goto exit_free;
890 
891 	resource->trip[0] = -1;
892 	resource->trip[1] = -1;
893 
894 	res = setup_attrs(resource);
895 	if (res)
896 		goto exit_free_capability;
897 
898 	resource->hwmon_dev = hwmon_device_register(&device->dev);
899 	if (IS_ERR(resource->hwmon_dev)) {
900 		res = PTR_ERR(resource->hwmon_dev);
901 		goto exit_remove;
902 	}
903 
904 	res = 0;
905 	goto exit;
906 
907 exit_remove:
908 	remove_attrs(resource);
909 exit_free_capability:
910 	free_capabilities(resource);
911 exit_free:
912 	kfree(resource);
913 exit:
914 	return res;
915 }
916 
917 static void acpi_power_meter_remove(struct acpi_device *device)
918 {
919 	struct acpi_power_meter_resource *resource;
920 
921 	if (!device || !acpi_driver_data(device))
922 		return;
923 
924 	resource = acpi_driver_data(device);
925 	hwmon_device_unregister(resource->hwmon_dev);
926 
927 	remove_attrs(resource);
928 	free_capabilities(resource);
929 
930 	kfree(resource);
931 }
932 
933 static int acpi_power_meter_resume(struct device *dev)
934 {
935 	struct acpi_power_meter_resource *resource;
936 
937 	if (!dev)
938 		return -EINVAL;
939 
940 	resource = acpi_driver_data(to_acpi_device(dev));
941 	if (!resource)
942 		return -EINVAL;
943 
944 	free_capabilities(resource);
945 	read_capabilities(resource);
946 
947 	return 0;
948 }
949 
950 static DEFINE_SIMPLE_DEV_PM_OPS(acpi_power_meter_pm, NULL,
951 				acpi_power_meter_resume);
952 
953 static struct acpi_driver acpi_power_meter_driver = {
954 	.name = "power_meter",
955 	.class = ACPI_POWER_METER_CLASS,
956 	.ids = power_meter_ids,
957 	.ops = {
958 		.add = acpi_power_meter_add,
959 		.remove = acpi_power_meter_remove,
960 		.notify = acpi_power_meter_notify,
961 		},
962 	.drv.pm = pm_sleep_ptr(&acpi_power_meter_pm),
963 };
964 
965 /* Module init/exit routines */
966 static int __init enable_cap_knobs(const struct dmi_system_id *d)
967 {
968 	cap_in_hardware = 1;
969 	return 0;
970 }
971 
972 static const struct dmi_system_id pm_dmi_table[] __initconst = {
973 	{
974 		enable_cap_knobs, "IBM Active Energy Manager",
975 		{
976 			DMI_MATCH(DMI_SYS_VENDOR, "IBM")
977 		},
978 	},
979 	{}
980 };
981 
982 static int __init acpi_power_meter_init(void)
983 {
984 	int result;
985 
986 	if (acpi_disabled)
987 		return -ENODEV;
988 
989 	dmi_check_system(pm_dmi_table);
990 
991 	result = acpi_bus_register_driver(&acpi_power_meter_driver);
992 	if (result < 0)
993 		return result;
994 
995 	return 0;
996 }
997 
998 static void __exit acpi_power_meter_exit(void)
999 {
1000 	acpi_bus_unregister_driver(&acpi_power_meter_driver);
1001 }
1002 
1003 MODULE_AUTHOR("Darrick J. Wong <darrick.wong@oracle.com>");
1004 MODULE_DESCRIPTION("ACPI 4.0 power meter driver");
1005 MODULE_LICENSE("GPL");
1006 
1007 module_param(force_cap_on, bool, 0644);
1008 MODULE_PARM_DESC(force_cap_on, "Enable power cap even it is unsafe to do so.");
1009 
1010 module_init(acpi_power_meter_init);
1011 module_exit(acpi_power_meter_exit);
1012