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_SUCCESS(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_SUCCESS(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 	int ret;
359 
360 	mutex_lock(&resource->lock);
361 	switch (attr->index) {
362 	case 0:
363 		val = resource->model_number;
364 		break;
365 	case 1:
366 		val = resource->serial_number;
367 		break;
368 	case 2:
369 		val = resource->oem_info;
370 		break;
371 	default:
372 		WARN(1, "Implementation error: unexpected attribute index %d\n",
373 		     attr->index);
374 		val = "";
375 		break;
376 	}
377 	ret = sprintf(buf, "%s\n", val);
378 	mutex_unlock(&resource->lock);
379 	return ret;
380 }
381 
382 static ssize_t show_val(struct device *dev,
383 			struct device_attribute *devattr,
384 			char *buf)
385 {
386 	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
387 	struct acpi_device *acpi_dev = to_acpi_device(dev);
388 	struct acpi_power_meter_resource *resource = acpi_dev->driver_data;
389 	u64 val = 0;
390 
391 	switch (attr->index) {
392 	case 0:
393 		val = resource->caps.min_avg_interval;
394 		break;
395 	case 1:
396 		val = resource->caps.max_avg_interval;
397 		break;
398 	case 2:
399 		val = resource->caps.min_cap * 1000;
400 		break;
401 	case 3:
402 		val = resource->caps.max_cap * 1000;
403 		break;
404 	case 4:
405 		if (resource->caps.hysteresis == UNKNOWN_HYSTERESIS)
406 			return sprintf(buf, "unknown\n");
407 
408 		val = resource->caps.hysteresis * 1000;
409 		break;
410 	case 5:
411 		if (resource->caps.flags & POWER_METER_IS_BATTERY)
412 			val = 1;
413 		else
414 			val = 0;
415 		break;
416 	case 6:
417 		if (resource->power > resource->cap)
418 			val = 1;
419 		else
420 			val = 0;
421 		break;
422 	case 7:
423 	case 8:
424 		if (resource->trip[attr->index - 7] < 0)
425 			return sprintf(buf, "unknown\n");
426 
427 		val = resource->trip[attr->index - 7] * 1000;
428 		break;
429 	default:
430 		WARN(1, "Implementation error: unexpected attribute index %d\n",
431 		     attr->index);
432 		break;
433 	}
434 
435 	return sprintf(buf, "%llu\n", val);
436 }
437 
438 static ssize_t show_accuracy(struct device *dev,
439 			     struct device_attribute *devattr,
440 			     char *buf)
441 {
442 	struct acpi_device *acpi_dev = to_acpi_device(dev);
443 	struct acpi_power_meter_resource *resource = acpi_dev->driver_data;
444 	unsigned int acc = resource->caps.accuracy;
445 
446 	return sprintf(buf, "%u.%u%%\n", acc / 1000, acc % 1000);
447 }
448 
449 static ssize_t show_name(struct device *dev,
450 			 struct device_attribute *devattr,
451 			 char *buf)
452 {
453 	return sprintf(buf, "%s\n", ACPI_POWER_METER_NAME);
454 }
455 
456 #define RO_SENSOR_TEMPLATE(_label, _show, _index)	\
457 	{						\
458 		.label = _label,			\
459 		.show  = _show,				\
460 		.index = _index,			\
461 	}
462 
463 #define RW_SENSOR_TEMPLATE(_label, _show, _set, _index)	\
464 	{						\
465 		.label = _label,			\
466 		.show  = _show,				\
467 		.set   = _set,				\
468 		.index = _index,			\
469 	}
470 
471 /* Sensor descriptions.  If you add a sensor, update NUM_SENSORS above! */
472 static struct sensor_template meter_attrs[] = {
473 	RO_SENSOR_TEMPLATE(POWER_AVERAGE_NAME, show_power, 0),
474 	RO_SENSOR_TEMPLATE("power1_accuracy", show_accuracy, 0),
475 	RO_SENSOR_TEMPLATE("power1_average_interval_min", show_val, 0),
476 	RO_SENSOR_TEMPLATE("power1_average_interval_max", show_val, 1),
477 	RO_SENSOR_TEMPLATE("power1_is_battery", show_val, 5),
478 	RW_SENSOR_TEMPLATE(POWER_AVG_INTERVAL_NAME, show_avg_interval,
479 		set_avg_interval, 0),
480 	{},
481 };
482 
483 static struct sensor_template misc_cap_attrs[] = {
484 	RO_SENSOR_TEMPLATE("power1_cap_min", show_val, 2),
485 	RO_SENSOR_TEMPLATE("power1_cap_max", show_val, 3),
486 	RO_SENSOR_TEMPLATE("power1_cap_hyst", show_val, 4),
487 	RO_SENSOR_TEMPLATE(POWER_ALARM_NAME, show_val, 6),
488 	{},
489 };
490 
491 static struct sensor_template ro_cap_attrs[] = {
492 	RO_SENSOR_TEMPLATE(POWER_CAP_NAME, show_cap, 0),
493 	{},
494 };
495 
496 static struct sensor_template rw_cap_attrs[] = {
497 	RW_SENSOR_TEMPLATE(POWER_CAP_NAME, show_cap, set_cap, 0),
498 	{},
499 };
500 
501 static struct sensor_template trip_attrs[] = {
502 	RW_SENSOR_TEMPLATE("power1_average_min", show_val, set_trip, 7),
503 	RW_SENSOR_TEMPLATE("power1_average_max", show_val, set_trip, 8),
504 	{},
505 };
506 
507 static struct sensor_template misc_attrs[] = {
508 	RO_SENSOR_TEMPLATE("name", show_name, 0),
509 	RO_SENSOR_TEMPLATE("power1_model_number", show_str, 0),
510 	RO_SENSOR_TEMPLATE("power1_oem_info", show_str, 2),
511 	RO_SENSOR_TEMPLATE("power1_serial_number", show_str, 1),
512 	{},
513 };
514 
515 #undef RO_SENSOR_TEMPLATE
516 #undef RW_SENSOR_TEMPLATE
517 
518 /* Read power domain data */
519 static void remove_domain_devices(struct acpi_power_meter_resource *resource)
520 {
521 	int i;
522 
523 	if (!resource->num_domain_devices)
524 		return;
525 
526 	for (i = 0; i < resource->num_domain_devices; i++) {
527 		struct acpi_device *obj = resource->domain_devices[i];
528 		if (!obj)
529 			continue;
530 
531 		sysfs_remove_link(resource->holders_dir,
532 				  kobject_name(&obj->dev.kobj));
533 		put_device(&obj->dev);
534 	}
535 
536 	kfree(resource->domain_devices);
537 	kobject_put(resource->holders_dir);
538 	resource->num_domain_devices = 0;
539 }
540 
541 static int read_domain_devices(struct acpi_power_meter_resource *resource)
542 {
543 	int res = 0;
544 	int i;
545 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
546 	union acpi_object *pss;
547 	acpi_status status;
548 
549 	status = acpi_evaluate_object(resource->acpi_dev->handle, "_PMD", NULL,
550 				      &buffer);
551 	if (ACPI_FAILURE(status)) {
552 		ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PMD"));
553 		return -ENODEV;
554 	}
555 
556 	pss = buffer.pointer;
557 	if (!pss ||
558 	    pss->type != ACPI_TYPE_PACKAGE) {
559 		dev_err(&resource->acpi_dev->dev, ACPI_POWER_METER_NAME
560 			"Invalid _PMD data\n");
561 		res = -EFAULT;
562 		goto end;
563 	}
564 
565 	if (!pss->package.count)
566 		goto end;
567 
568 	resource->domain_devices = kcalloc(pss->package.count,
569 					   sizeof(struct acpi_device *),
570 					   GFP_KERNEL);
571 	if (!resource->domain_devices) {
572 		res = -ENOMEM;
573 		goto end;
574 	}
575 
576 	resource->holders_dir = kobject_create_and_add("measures",
577 					&resource->acpi_dev->dev.kobj);
578 	if (!resource->holders_dir) {
579 		res = -ENOMEM;
580 		goto exit_free;
581 	}
582 
583 	resource->num_domain_devices = pss->package.count;
584 
585 	for (i = 0; i < pss->package.count; i++) {
586 		struct acpi_device *obj;
587 		union acpi_object *element = &(pss->package.elements[i]);
588 
589 		/* Refuse non-references */
590 		if (element->type != ACPI_TYPE_LOCAL_REFERENCE)
591 			continue;
592 
593 		/* Create a symlink to domain objects */
594 		resource->domain_devices[i] = NULL;
595 		if (acpi_bus_get_device(element->reference.handle,
596 					&resource->domain_devices[i]))
597 			continue;
598 
599 		obj = resource->domain_devices[i];
600 		get_device(&obj->dev);
601 
602 		res = sysfs_create_link(resource->holders_dir, &obj->dev.kobj,
603 				      kobject_name(&obj->dev.kobj));
604 		if (res) {
605 			put_device(&obj->dev);
606 			resource->domain_devices[i] = NULL;
607 		}
608 	}
609 
610 	res = 0;
611 	goto end;
612 
613 exit_free:
614 	kfree(resource->domain_devices);
615 end:
616 	kfree(buffer.pointer);
617 	return res;
618 }
619 
620 /* Registration and deregistration */
621 static int register_attrs(struct acpi_power_meter_resource *resource,
622 			  struct sensor_template *attrs)
623 {
624 	struct device *dev = &resource->acpi_dev->dev;
625 	struct sensor_device_attribute *sensors =
626 		&resource->sensors[resource->num_sensors];
627 	int res = 0;
628 
629 	while (attrs->label) {
630 		sensors->dev_attr.attr.name = attrs->label;
631 		sensors->dev_attr.attr.mode = 0444;
632 		sensors->dev_attr.show = attrs->show;
633 		sensors->index = attrs->index;
634 
635 		if (attrs->set) {
636 			sensors->dev_attr.attr.mode |= 0200;
637 			sensors->dev_attr.store = attrs->set;
638 		}
639 
640 		sysfs_attr_init(&sensors->dev_attr.attr);
641 		res = device_create_file(dev, &sensors->dev_attr);
642 		if (res) {
643 			sensors->dev_attr.attr.name = NULL;
644 			goto error;
645 		}
646 		sensors++;
647 		resource->num_sensors++;
648 		attrs++;
649 	}
650 
651 error:
652 	return res;
653 }
654 
655 static void remove_attrs(struct acpi_power_meter_resource *resource)
656 {
657 	int i;
658 
659 	for (i = 0; i < resource->num_sensors; i++) {
660 		if (!resource->sensors[i].dev_attr.attr.name)
661 			continue;
662 		device_remove_file(&resource->acpi_dev->dev,
663 				   &resource->sensors[i].dev_attr);
664 	}
665 
666 	remove_domain_devices(resource);
667 
668 	resource->num_sensors = 0;
669 }
670 
671 static int setup_attrs(struct acpi_power_meter_resource *resource)
672 {
673 	int res = 0;
674 
675 	res = read_domain_devices(resource);
676 	if (res)
677 		return res;
678 
679 	if (resource->caps.flags & POWER_METER_CAN_MEASURE) {
680 		res = register_attrs(resource, meter_attrs);
681 		if (res)
682 			goto error;
683 	}
684 
685 	if (resource->caps.flags & POWER_METER_CAN_CAP) {
686 		if (!can_cap_in_hardware()) {
687 			dev_warn(&resource->acpi_dev->dev,
688 				 "Ignoring unsafe software power cap!\n");
689 			goto skip_unsafe_cap;
690 		}
691 
692 		if (resource->caps.configurable_cap)
693 			res = register_attrs(resource, rw_cap_attrs);
694 		else
695 			res = register_attrs(resource, ro_cap_attrs);
696 
697 		if (res)
698 			goto error;
699 
700 		res = register_attrs(resource, misc_cap_attrs);
701 		if (res)
702 			goto error;
703 	}
704 
705 skip_unsafe_cap:
706 	if (resource->caps.flags & POWER_METER_CAN_TRIP) {
707 		res = register_attrs(resource, trip_attrs);
708 		if (res)
709 			goto error;
710 	}
711 
712 	res = register_attrs(resource, misc_attrs);
713 	if (res)
714 		goto error;
715 
716 	return res;
717 error:
718 	remove_attrs(resource);
719 	return res;
720 }
721 
722 static void free_capabilities(struct acpi_power_meter_resource *resource)
723 {
724 	acpi_string *str;
725 	int i;
726 
727 	str = &resource->model_number;
728 	for (i = 0; i < 3; i++, str++) {
729 		kfree(*str);
730 		*str = NULL;
731 	}
732 }
733 
734 static int read_capabilities(struct acpi_power_meter_resource *resource)
735 {
736 	int res = 0;
737 	int i;
738 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
739 	struct acpi_buffer state = { 0, NULL };
740 	struct acpi_buffer format = { sizeof("NNNNNNNNNNN"), "NNNNNNNNNNN" };
741 	union acpi_object *pss;
742 	acpi_string *str;
743 	acpi_status status;
744 
745 	status = acpi_evaluate_object(resource->acpi_dev->handle, "_PMC", NULL,
746 				      &buffer);
747 	if (ACPI_FAILURE(status)) {
748 		ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PMC"));
749 		return -ENODEV;
750 	}
751 
752 	pss = buffer.pointer;
753 	if (!pss ||
754 	    pss->type != ACPI_TYPE_PACKAGE ||
755 	    pss->package.count != 14) {
756 		dev_err(&resource->acpi_dev->dev, ACPI_POWER_METER_NAME
757 			"Invalid _PMC data\n");
758 		res = -EFAULT;
759 		goto end;
760 	}
761 
762 	/* Grab all the integer data at once */
763 	state.length = sizeof(struct acpi_power_meter_capabilities);
764 	state.pointer = &resource->caps;
765 
766 	status = acpi_extract_package(pss, &format, &state);
767 	if (ACPI_FAILURE(status)) {
768 		ACPI_EXCEPTION((AE_INFO, status, "Invalid data"));
769 		res = -EFAULT;
770 		goto end;
771 	}
772 
773 	if (resource->caps.units) {
774 		dev_err(&resource->acpi_dev->dev, ACPI_POWER_METER_NAME
775 			"Unknown units %llu.\n",
776 			resource->caps.units);
777 		res = -EINVAL;
778 		goto end;
779 	}
780 
781 	/* Grab the string data */
782 	str = &resource->model_number;
783 
784 	for (i = 11; i < 14; i++) {
785 		union acpi_object *element = &(pss->package.elements[i]);
786 
787 		if (element->type != ACPI_TYPE_STRING) {
788 			res = -EINVAL;
789 			goto error;
790 		}
791 
792 		*str = kcalloc(element->string.length + 1, sizeof(u8),
793 			       GFP_KERNEL);
794 		if (!*str) {
795 			res = -ENOMEM;
796 			goto error;
797 		}
798 
799 		strncpy(*str, element->string.pointer, element->string.length);
800 		str++;
801 	}
802 
803 	dev_info(&resource->acpi_dev->dev, "Found ACPI power meter.\n");
804 	goto end;
805 error:
806 	free_capabilities(resource);
807 end:
808 	kfree(buffer.pointer);
809 	return res;
810 }
811 
812 /* Handle ACPI event notifications */
813 static void acpi_power_meter_notify(struct acpi_device *device, u32 event)
814 {
815 	struct acpi_power_meter_resource *resource;
816 	int res;
817 
818 	if (!device || !acpi_driver_data(device))
819 		return;
820 
821 	resource = acpi_driver_data(device);
822 
823 	switch (event) {
824 	case METER_NOTIFY_CONFIG:
825 		mutex_lock(&resource->lock);
826 		free_capabilities(resource);
827 		res = read_capabilities(resource);
828 		mutex_unlock(&resource->lock);
829 		if (res)
830 			break;
831 
832 		remove_attrs(resource);
833 		setup_attrs(resource);
834 		break;
835 	case METER_NOTIFY_TRIP:
836 		sysfs_notify(&device->dev.kobj, NULL, POWER_AVERAGE_NAME);
837 		break;
838 	case METER_NOTIFY_CAP:
839 		sysfs_notify(&device->dev.kobj, NULL, POWER_CAP_NAME);
840 		break;
841 	case METER_NOTIFY_INTERVAL:
842 		sysfs_notify(&device->dev.kobj, NULL, POWER_AVG_INTERVAL_NAME);
843 		break;
844 	case METER_NOTIFY_CAPPING:
845 		sysfs_notify(&device->dev.kobj, NULL, POWER_ALARM_NAME);
846 		dev_info(&device->dev, "Capping in progress.\n");
847 		break;
848 	default:
849 		WARN(1, "Unexpected event %d\n", event);
850 		break;
851 	}
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 	res = read_capabilities(resource);
878 	if (res)
879 		goto exit_free;
880 
881 	resource->trip[0] = resource->trip[1] = -1;
882 
883 	res = setup_attrs(resource);
884 	if (res)
885 		goto exit_free_capability;
886 
887 	resource->hwmon_dev = hwmon_device_register(&device->dev);
888 	if (IS_ERR(resource->hwmon_dev)) {
889 		res = PTR_ERR(resource->hwmon_dev);
890 		goto exit_remove;
891 	}
892 
893 	res = 0;
894 	goto exit;
895 
896 exit_remove:
897 	remove_attrs(resource);
898 exit_free_capability:
899 	free_capabilities(resource);
900 exit_free:
901 	kfree(resource);
902 exit:
903 	return res;
904 }
905 
906 static int acpi_power_meter_remove(struct acpi_device *device)
907 {
908 	struct acpi_power_meter_resource *resource;
909 
910 	if (!device || !acpi_driver_data(device))
911 		return -EINVAL;
912 
913 	resource = acpi_driver_data(device);
914 	hwmon_device_unregister(resource->hwmon_dev);
915 
916 	remove_attrs(resource);
917 	free_capabilities(resource);
918 
919 	kfree(resource);
920 	return 0;
921 }
922 
923 #ifdef CONFIG_PM_SLEEP
924 
925 static int acpi_power_meter_resume(struct device *dev)
926 {
927 	struct acpi_power_meter_resource *resource;
928 
929 	if (!dev)
930 		return -EINVAL;
931 
932 	resource = acpi_driver_data(to_acpi_device(dev));
933 	if (!resource)
934 		return -EINVAL;
935 
936 	free_capabilities(resource);
937 	read_capabilities(resource);
938 
939 	return 0;
940 }
941 
942 #endif /* CONFIG_PM_SLEEP */
943 
944 static SIMPLE_DEV_PM_OPS(acpi_power_meter_pm, NULL, acpi_power_meter_resume);
945 
946 static struct acpi_driver acpi_power_meter_driver = {
947 	.name = "power_meter",
948 	.class = ACPI_POWER_METER_CLASS,
949 	.ids = power_meter_ids,
950 	.ops = {
951 		.add = acpi_power_meter_add,
952 		.remove = acpi_power_meter_remove,
953 		.notify = acpi_power_meter_notify,
954 		},
955 	.drv.pm = &acpi_power_meter_pm,
956 };
957 
958 /* Module init/exit routines */
959 static int __init enable_cap_knobs(const struct dmi_system_id *d)
960 {
961 	cap_in_hardware = 1;
962 	return 0;
963 }
964 
965 static const struct dmi_system_id pm_dmi_table[] __initconst = {
966 	{
967 		enable_cap_knobs, "IBM Active Energy Manager",
968 		{
969 			DMI_MATCH(DMI_SYS_VENDOR, "IBM")
970 		},
971 	},
972 	{}
973 };
974 
975 static int __init acpi_power_meter_init(void)
976 {
977 	int result;
978 
979 	if (acpi_disabled)
980 		return -ENODEV;
981 
982 	dmi_check_system(pm_dmi_table);
983 
984 	result = acpi_bus_register_driver(&acpi_power_meter_driver);
985 	if (result < 0)
986 		return result;
987 
988 	return 0;
989 }
990 
991 static void __exit acpi_power_meter_exit(void)
992 {
993 	acpi_bus_unregister_driver(&acpi_power_meter_driver);
994 }
995 
996 MODULE_AUTHOR("Darrick J. Wong <darrick.wong@oracle.com>");
997 MODULE_DESCRIPTION("ACPI 4.0 power meter driver");
998 MODULE_LICENSE("GPL");
999 
1000 module_param(force_cap_on, bool, 0644);
1001 MODULE_PARM_DESC(force_cap_on, "Enable power cap even it is unsafe to do so.");
1002 
1003 module_init(acpi_power_meter_init);
1004 module_exit(acpi_power_meter_exit);
1005