xref: /openbmc/linux/drivers/hwmon/acpi_power_meter.c (revision ce932d0c5589e9766e089c22c66890dfc48fbd94)
1 /*
2  * A hwmon driver for ACPI 4.0 power meters
3  * Copyright (C) 2009 IBM
4  *
5  * Author: Darrick J. Wong <djwong@us.ibm.com>
6  *
7  * This program is free software; you can redistribute it and/or modify
8  * it under the terms of the GNU General Public License as published by
9  * the Free Software Foundation; either version 2 of the License, or
10  * (at your option) any later version.
11  *
12  * This program is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15  * GNU General Public License for more details.
16  *
17  * You should have received a copy of the GNU General Public License
18  * along with this program; if not, write to the Free Software
19  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
20  */
21 
22 #include <linux/module.h>
23 #include <linux/hwmon.h>
24 #include <linux/hwmon-sysfs.h>
25 #include <linux/jiffies.h>
26 #include <linux/mutex.h>
27 #include <linux/dmi.h>
28 #include <linux/slab.h>
29 #include <linux/kdev_t.h>
30 #include <linux/sched.h>
31 #include <linux/time.h>
32 #include <acpi/acpi_drivers.h>
33 #include <acpi/acpi_bus.h>
34 
35 #define ACPI_POWER_METER_NAME		"power_meter"
36 ACPI_MODULE_NAME(ACPI_POWER_METER_NAME);
37 #define ACPI_POWER_METER_DEVICE_NAME	"Power Meter"
38 #define ACPI_POWER_METER_CLASS		"pwr_meter_resource"
39 
40 #define NUM_SENSORS			17
41 
42 #define POWER_METER_CAN_MEASURE	(1 << 0)
43 #define POWER_METER_CAN_TRIP	(1 << 1)
44 #define POWER_METER_CAN_CAP	(1 << 2)
45 #define POWER_METER_CAN_NOTIFY	(1 << 3)
46 #define POWER_METER_IS_BATTERY	(1 << 8)
47 #define UNKNOWN_HYSTERESIS	0xFFFFFFFF
48 
49 #define METER_NOTIFY_CONFIG	0x80
50 #define METER_NOTIFY_TRIP	0x81
51 #define METER_NOTIFY_CAP	0x82
52 #define METER_NOTIFY_CAPPING	0x83
53 #define METER_NOTIFY_INTERVAL	0x84
54 
55 #define POWER_AVERAGE_NAME	"power1_average"
56 #define POWER_CAP_NAME		"power1_cap"
57 #define POWER_AVG_INTERVAL_NAME	"power1_average_interval"
58 #define POWER_ALARM_NAME	"power1_alarm"
59 
60 static int cap_in_hardware;
61 static bool force_cap_on;
62 
63 static int can_cap_in_hardware(void)
64 {
65 	return force_cap_on || cap_in_hardware;
66 }
67 
68 static const struct acpi_device_id power_meter_ids[] = {
69 	{"ACPI000D", 0},
70 	{"", 0},
71 };
72 MODULE_DEVICE_TABLE(acpi, power_meter_ids);
73 
74 struct acpi_power_meter_capabilities {
75 	u64		flags;
76 	u64		units;
77 	u64		type;
78 	u64		accuracy;
79 	u64		sampling_time;
80 	u64		min_avg_interval;
81 	u64		max_avg_interval;
82 	u64		hysteresis;
83 	u64		configurable_cap;
84 	u64		min_cap;
85 	u64		max_cap;
86 };
87 
88 struct acpi_power_meter_resource {
89 	struct acpi_device	*acpi_dev;
90 	acpi_bus_id		name;
91 	struct mutex		lock;
92 	struct device		*hwmon_dev;
93 	struct acpi_power_meter_capabilities	caps;
94 	acpi_string		model_number;
95 	acpi_string		serial_number;
96 	acpi_string		oem_info;
97 	u64		power;
98 	u64		cap;
99 	u64		avg_interval;
100 	int			sensors_valid;
101 	unsigned long		sensors_last_updated;
102 	struct sensor_device_attribute	sensors[NUM_SENSORS];
103 	int			num_sensors;
104 	int			trip[2];
105 	int			num_domain_devices;
106 	struct acpi_device	**domain_devices;
107 	struct kobject		*holders_dir;
108 };
109 
110 struct ro_sensor_template {
111 	char *label;
112 	ssize_t (*show)(struct device *dev,
113 			struct device_attribute *devattr,
114 			char *buf);
115 	int index;
116 };
117 
118 struct rw_sensor_template {
119 	char *label;
120 	ssize_t (*show)(struct device *dev,
121 			struct device_attribute *devattr,
122 			char *buf);
123 	ssize_t (*set)(struct device *dev,
124 		       struct device_attribute *devattr,
125 		       const char *buf, size_t count);
126 	int index;
127 };
128 
129 /* Averaging interval */
130 static int update_avg_interval(struct acpi_power_meter_resource *resource)
131 {
132 	unsigned long long data;
133 	acpi_status status;
134 
135 	status = acpi_evaluate_integer(resource->acpi_dev->handle, "_GAI",
136 				       NULL, &data);
137 	if (ACPI_FAILURE(status)) {
138 		ACPI_EXCEPTION((AE_INFO, status, "Evaluating _GAI"));
139 		return -ENODEV;
140 	}
141 
142 	resource->avg_interval = data;
143 	return 0;
144 }
145 
146 static ssize_t show_avg_interval(struct device *dev,
147 				 struct device_attribute *devattr,
148 				 char *buf)
149 {
150 	struct acpi_device *acpi_dev = to_acpi_device(dev);
151 	struct acpi_power_meter_resource *resource = acpi_dev->driver_data;
152 
153 	mutex_lock(&resource->lock);
154 	update_avg_interval(resource);
155 	mutex_unlock(&resource->lock);
156 
157 	return sprintf(buf, "%llu\n", resource->avg_interval);
158 }
159 
160 static ssize_t set_avg_interval(struct device *dev,
161 				struct device_attribute *devattr,
162 				const char *buf, size_t count)
163 {
164 	struct acpi_device *acpi_dev = to_acpi_device(dev);
165 	struct acpi_power_meter_resource *resource = acpi_dev->driver_data;
166 	union acpi_object arg0 = { ACPI_TYPE_INTEGER };
167 	struct acpi_object_list args = { 1, &arg0 };
168 	int res;
169 	unsigned long temp;
170 	unsigned long long data;
171 	acpi_status status;
172 
173 	res = kstrtoul(buf, 10, &temp);
174 	if (res)
175 		return res;
176 
177 	if (temp > resource->caps.max_avg_interval ||
178 	    temp < resource->caps.min_avg_interval)
179 		return -EINVAL;
180 	arg0.integer.value = temp;
181 
182 	mutex_lock(&resource->lock);
183 	status = acpi_evaluate_integer(resource->acpi_dev->handle, "_PAI",
184 				       &args, &data);
185 	if (!ACPI_FAILURE(status))
186 		resource->avg_interval = temp;
187 	mutex_unlock(&resource->lock);
188 
189 	if (ACPI_FAILURE(status)) {
190 		ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PAI"));
191 		return -EINVAL;
192 	}
193 
194 	/* _PAI returns 0 on success, nonzero otherwise */
195 	if (data)
196 		return -EINVAL;
197 
198 	return count;
199 }
200 
201 /* Cap functions */
202 static int update_cap(struct acpi_power_meter_resource *resource)
203 {
204 	unsigned long long data;
205 	acpi_status status;
206 
207 	status = acpi_evaluate_integer(resource->acpi_dev->handle, "_GHL",
208 				       NULL, &data);
209 	if (ACPI_FAILURE(status)) {
210 		ACPI_EXCEPTION((AE_INFO, status, "Evaluating _GHL"));
211 		return -ENODEV;
212 	}
213 
214 	resource->cap = data;
215 	return 0;
216 }
217 
218 static ssize_t show_cap(struct device *dev,
219 			struct device_attribute *devattr,
220 			char *buf)
221 {
222 	struct acpi_device *acpi_dev = to_acpi_device(dev);
223 	struct acpi_power_meter_resource *resource = acpi_dev->driver_data;
224 
225 	mutex_lock(&resource->lock);
226 	update_cap(resource);
227 	mutex_unlock(&resource->lock);
228 
229 	return sprintf(buf, "%llu\n", resource->cap * 1000);
230 }
231 
232 static ssize_t set_cap(struct device *dev, struct device_attribute *devattr,
233 		       const char *buf, size_t count)
234 {
235 	struct acpi_device *acpi_dev = to_acpi_device(dev);
236 	struct acpi_power_meter_resource *resource = acpi_dev->driver_data;
237 	union acpi_object arg0 = { ACPI_TYPE_INTEGER };
238 	struct acpi_object_list args = { 1, &arg0 };
239 	int res;
240 	unsigned long temp;
241 	unsigned long long data;
242 	acpi_status status;
243 
244 	res = kstrtoul(buf, 10, &temp);
245 	if (res)
246 		return res;
247 
248 	temp /= 1000;
249 	if (temp > resource->caps.max_cap || temp < resource->caps.min_cap)
250 		return -EINVAL;
251 	arg0.integer.value = temp;
252 
253 	mutex_lock(&resource->lock);
254 	status = acpi_evaluate_integer(resource->acpi_dev->handle, "_SHL",
255 				       &args, &data);
256 	if (!ACPI_FAILURE(status))
257 		resource->cap = temp;
258 	mutex_unlock(&resource->lock);
259 
260 	if (ACPI_FAILURE(status)) {
261 		ACPI_EXCEPTION((AE_INFO, status, "Evaluating _SHL"));
262 		return -EINVAL;
263 	}
264 
265 	/* _SHL returns 0 on success, nonzero otherwise */
266 	if (data)
267 		return -EINVAL;
268 
269 	return count;
270 }
271 
272 /* Power meter trip points */
273 static int set_acpi_trip(struct acpi_power_meter_resource *resource)
274 {
275 	union acpi_object arg_objs[] = {
276 		{ACPI_TYPE_INTEGER},
277 		{ACPI_TYPE_INTEGER}
278 	};
279 	struct acpi_object_list args = { 2, arg_objs };
280 	unsigned long long data;
281 	acpi_status status;
282 
283 	/* Both trip levels must be set */
284 	if (resource->trip[0] < 0 || resource->trip[1] < 0)
285 		return 0;
286 
287 	/* This driver stores min, max; ACPI wants max, min. */
288 	arg_objs[0].integer.value = resource->trip[1];
289 	arg_objs[1].integer.value = resource->trip[0];
290 
291 	status = acpi_evaluate_integer(resource->acpi_dev->handle, "_PTP",
292 				       &args, &data);
293 	if (ACPI_FAILURE(status)) {
294 		ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PTP"));
295 		return -EINVAL;
296 	}
297 
298 	/* _PTP returns 0 on success, nonzero otherwise */
299 	if (data)
300 		return -EINVAL;
301 
302 	return 0;
303 }
304 
305 static ssize_t set_trip(struct device *dev, struct device_attribute *devattr,
306 			const char *buf, size_t count)
307 {
308 	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
309 	struct acpi_device *acpi_dev = to_acpi_device(dev);
310 	struct acpi_power_meter_resource *resource = acpi_dev->driver_data;
311 	int res;
312 	unsigned long temp;
313 
314 	res = kstrtoul(buf, 10, &temp);
315 	if (res)
316 		return res;
317 
318 	temp /= 1000;
319 	if (temp < 0)
320 		return -EINVAL;
321 
322 	mutex_lock(&resource->lock);
323 	resource->trip[attr->index - 7] = temp;
324 	res = set_acpi_trip(resource);
325 	mutex_unlock(&resource->lock);
326 
327 	if (res)
328 		return res;
329 
330 	return count;
331 }
332 
333 /* Power meter */
334 static int update_meter(struct acpi_power_meter_resource *resource)
335 {
336 	unsigned long long data;
337 	acpi_status status;
338 	unsigned long local_jiffies = jiffies;
339 
340 	if (time_before(local_jiffies, resource->sensors_last_updated +
341 			msecs_to_jiffies(resource->caps.sampling_time)) &&
342 			resource->sensors_valid)
343 		return 0;
344 
345 	status = acpi_evaluate_integer(resource->acpi_dev->handle, "_PMM",
346 				       NULL, &data);
347 	if (ACPI_FAILURE(status)) {
348 		ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PMM"));
349 		return -ENODEV;
350 	}
351 
352 	resource->power = data;
353 	resource->sensors_valid = 1;
354 	resource->sensors_last_updated = jiffies;
355 	return 0;
356 }
357 
358 static ssize_t show_power(struct device *dev,
359 			  struct device_attribute *devattr,
360 			  char *buf)
361 {
362 	struct acpi_device *acpi_dev = to_acpi_device(dev);
363 	struct acpi_power_meter_resource *resource = acpi_dev->driver_data;
364 
365 	mutex_lock(&resource->lock);
366 	update_meter(resource);
367 	mutex_unlock(&resource->lock);
368 
369 	return sprintf(buf, "%llu\n", resource->power * 1000);
370 }
371 
372 /* Miscellaneous */
373 static ssize_t show_str(struct device *dev,
374 			struct device_attribute *devattr,
375 			char *buf)
376 {
377 	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
378 	struct acpi_device *acpi_dev = to_acpi_device(dev);
379 	struct acpi_power_meter_resource *resource = acpi_dev->driver_data;
380 	acpi_string val;
381 
382 	switch (attr->index) {
383 	case 0:
384 		val = resource->model_number;
385 		break;
386 	case 1:
387 		val = resource->serial_number;
388 		break;
389 	case 2:
390 		val = resource->oem_info;
391 		break;
392 	default:
393 		BUG();
394 		val = "";
395 	}
396 
397 	return sprintf(buf, "%s\n", val);
398 }
399 
400 static ssize_t show_val(struct device *dev,
401 			struct device_attribute *devattr,
402 			char *buf)
403 {
404 	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
405 	struct acpi_device *acpi_dev = to_acpi_device(dev);
406 	struct acpi_power_meter_resource *resource = acpi_dev->driver_data;
407 	u64 val = 0;
408 
409 	switch (attr->index) {
410 	case 0:
411 		val = resource->caps.min_avg_interval;
412 		break;
413 	case 1:
414 		val = resource->caps.max_avg_interval;
415 		break;
416 	case 2:
417 		val = resource->caps.min_cap * 1000;
418 		break;
419 	case 3:
420 		val = resource->caps.max_cap * 1000;
421 		break;
422 	case 4:
423 		if (resource->caps.hysteresis == UNKNOWN_HYSTERESIS)
424 			return sprintf(buf, "unknown\n");
425 
426 		val = resource->caps.hysteresis * 1000;
427 		break;
428 	case 5:
429 		if (resource->caps.flags & POWER_METER_IS_BATTERY)
430 			val = 1;
431 		else
432 			val = 0;
433 		break;
434 	case 6:
435 		if (resource->power > resource->cap)
436 			val = 1;
437 		else
438 			val = 0;
439 		break;
440 	case 7:
441 	case 8:
442 		if (resource->trip[attr->index - 7] < 0)
443 			return sprintf(buf, "unknown\n");
444 
445 		val = resource->trip[attr->index - 7] * 1000;
446 		break;
447 	default:
448 		BUG();
449 	}
450 
451 	return sprintf(buf, "%llu\n", val);
452 }
453 
454 static ssize_t show_accuracy(struct device *dev,
455 			     struct device_attribute *devattr,
456 			     char *buf)
457 {
458 	struct acpi_device *acpi_dev = to_acpi_device(dev);
459 	struct acpi_power_meter_resource *resource = acpi_dev->driver_data;
460 	unsigned int acc = resource->caps.accuracy;
461 
462 	return sprintf(buf, "%u.%u%%\n", acc / 1000, acc % 1000);
463 }
464 
465 static ssize_t show_name(struct device *dev,
466 			 struct device_attribute *devattr,
467 			 char *buf)
468 {
469 	return sprintf(buf, "%s\n", ACPI_POWER_METER_NAME);
470 }
471 
472 /* Sensor descriptions.  If you add a sensor, update NUM_SENSORS above! */
473 static struct ro_sensor_template meter_ro_attrs[] = {
474 {POWER_AVERAGE_NAME, show_power, 0},
475 {"power1_accuracy", show_accuracy, 0},
476 {"power1_average_interval_min", show_val, 0},
477 {"power1_average_interval_max", show_val, 1},
478 {"power1_is_battery", show_val, 5},
479 {NULL, NULL, 0},
480 };
481 
482 static struct rw_sensor_template meter_rw_attrs[] = {
483 {POWER_AVG_INTERVAL_NAME, show_avg_interval, set_avg_interval, 0},
484 {NULL, NULL, NULL, 0},
485 };
486 
487 static struct ro_sensor_template misc_cap_attrs[] = {
488 {"power1_cap_min", show_val, 2},
489 {"power1_cap_max", show_val, 3},
490 {"power1_cap_hyst", show_val, 4},
491 {POWER_ALARM_NAME, show_val, 6},
492 {NULL, NULL, 0},
493 };
494 
495 static struct ro_sensor_template ro_cap_attrs[] = {
496 {POWER_CAP_NAME, show_cap, 0},
497 {NULL, NULL, 0},
498 };
499 
500 static struct rw_sensor_template rw_cap_attrs[] = {
501 {POWER_CAP_NAME, show_cap, set_cap, 0},
502 {NULL, NULL, NULL, 0},
503 };
504 
505 static struct rw_sensor_template trip_attrs[] = {
506 {"power1_average_min", show_val, set_trip, 7},
507 {"power1_average_max", show_val, set_trip, 8},
508 {NULL, NULL, NULL, 0},
509 };
510 
511 static struct ro_sensor_template misc_attrs[] = {
512 {"name", show_name, 0},
513 {"power1_model_number", show_str, 0},
514 {"power1_oem_info", show_str, 2},
515 {"power1_serial_number", show_str, 1},
516 {NULL, NULL, 0},
517 };
518 
519 /* Read power domain data */
520 static void remove_domain_devices(struct acpi_power_meter_resource *resource)
521 {
522 	int i;
523 
524 	if (!resource->num_domain_devices)
525 		return;
526 
527 	for (i = 0; i < resource->num_domain_devices; i++) {
528 		struct acpi_device *obj = resource->domain_devices[i];
529 		if (!obj)
530 			continue;
531 
532 		sysfs_remove_link(resource->holders_dir,
533 				  kobject_name(&obj->dev.kobj));
534 		put_device(&obj->dev);
535 	}
536 
537 	kfree(resource->domain_devices);
538 	kobject_put(resource->holders_dir);
539 	resource->num_domain_devices = 0;
540 }
541 
542 static int read_domain_devices(struct acpi_power_meter_resource *resource)
543 {
544 	int res = 0;
545 	int i;
546 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
547 	union acpi_object *pss;
548 	acpi_status status;
549 
550 	status = acpi_evaluate_object(resource->acpi_dev->handle, "_PMD", NULL,
551 				      &buffer);
552 	if (ACPI_FAILURE(status)) {
553 		ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PMD"));
554 		return -ENODEV;
555 	}
556 
557 	pss = buffer.pointer;
558 	if (!pss ||
559 	    pss->type != ACPI_TYPE_PACKAGE) {
560 		dev_err(&resource->acpi_dev->dev, ACPI_POWER_METER_NAME
561 			"Invalid _PMD data\n");
562 		res = -EFAULT;
563 		goto end;
564 	}
565 
566 	if (!pss->package.count)
567 		goto end;
568 
569 	resource->domain_devices = kzalloc(sizeof(struct acpi_device *) *
570 					   pss->package.count, 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 		status = acpi_bus_get_device(element->reference.handle,
596 					     &resource->domain_devices[i]);
597 		if (ACPI_FAILURE(status))
598 			continue;
599 
600 		obj = resource->domain_devices[i];
601 		get_device(&obj->dev);
602 
603 		res = sysfs_create_link(resource->holders_dir, &obj->dev.kobj,
604 				      kobject_name(&obj->dev.kobj));
605 		if (res) {
606 			put_device(&obj->dev);
607 			resource->domain_devices[i] = NULL;
608 		}
609 	}
610 
611 	res = 0;
612 	goto end;
613 
614 exit_free:
615 	kfree(resource->domain_devices);
616 end:
617 	kfree(buffer.pointer);
618 	return res;
619 }
620 
621 /* Registration and deregistration */
622 static int register_ro_attrs(struct acpi_power_meter_resource *resource,
623 			     struct ro_sensor_template *ro)
624 {
625 	struct device *dev = &resource->acpi_dev->dev;
626 	struct sensor_device_attribute *sensors =
627 		&resource->sensors[resource->num_sensors];
628 	int res = 0;
629 
630 	while (ro->label) {
631 		sensors->dev_attr.attr.name = ro->label;
632 		sensors->dev_attr.attr.mode = S_IRUGO;
633 		sensors->dev_attr.show = ro->show;
634 		sensors->index = ro->index;
635 
636 		sysfs_attr_init(&sensors->dev_attr.attr);
637 		res = device_create_file(dev, &sensors->dev_attr);
638 		if (res) {
639 			sensors->dev_attr.attr.name = NULL;
640 			goto error;
641 		}
642 		sensors++;
643 		resource->num_sensors++;
644 		ro++;
645 	}
646 
647 error:
648 	return res;
649 }
650 
651 static int register_rw_attrs(struct acpi_power_meter_resource *resource,
652 			     struct rw_sensor_template *rw)
653 {
654 	struct device *dev = &resource->acpi_dev->dev;
655 	struct sensor_device_attribute *sensors =
656 		&resource->sensors[resource->num_sensors];
657 	int res = 0;
658 
659 	while (rw->label) {
660 		sensors->dev_attr.attr.name = rw->label;
661 		sensors->dev_attr.attr.mode = S_IRUGO | S_IWUSR;
662 		sensors->dev_attr.show = rw->show;
663 		sensors->dev_attr.store = rw->set;
664 		sensors->index = rw->index;
665 
666 		sysfs_attr_init(&sensors->dev_attr.attr);
667 		res = device_create_file(dev, &sensors->dev_attr);
668 		if (res) {
669 			sensors->dev_attr.attr.name = NULL;
670 			goto error;
671 		}
672 		sensors++;
673 		resource->num_sensors++;
674 		rw++;
675 	}
676 
677 error:
678 	return res;
679 }
680 
681 static void remove_attrs(struct acpi_power_meter_resource *resource)
682 {
683 	int i;
684 
685 	for (i = 0; i < resource->num_sensors; i++) {
686 		if (!resource->sensors[i].dev_attr.attr.name)
687 			continue;
688 		device_remove_file(&resource->acpi_dev->dev,
689 				   &resource->sensors[i].dev_attr);
690 	}
691 
692 	remove_domain_devices(resource);
693 
694 	resource->num_sensors = 0;
695 }
696 
697 static int setup_attrs(struct acpi_power_meter_resource *resource)
698 {
699 	int res = 0;
700 
701 	res = read_domain_devices(resource);
702 	if (res)
703 		return res;
704 
705 	if (resource->caps.flags & POWER_METER_CAN_MEASURE) {
706 		res = register_ro_attrs(resource, meter_ro_attrs);
707 		if (res)
708 			goto error;
709 		res = register_rw_attrs(resource, meter_rw_attrs);
710 		if (res)
711 			goto error;
712 	}
713 
714 	if (resource->caps.flags & POWER_METER_CAN_CAP) {
715 		if (!can_cap_in_hardware()) {
716 			dev_err(&resource->acpi_dev->dev,
717 				"Ignoring unsafe software power cap!\n");
718 			goto skip_unsafe_cap;
719 		}
720 
721 		if (resource->caps.configurable_cap) {
722 			res = register_rw_attrs(resource, rw_cap_attrs);
723 			if (res)
724 				goto error;
725 		} else {
726 			res = register_ro_attrs(resource, ro_cap_attrs);
727 			if (res)
728 				goto error;
729 		}
730 		res = register_ro_attrs(resource, misc_cap_attrs);
731 		if (res)
732 			goto error;
733 	}
734 skip_unsafe_cap:
735 
736 	if (resource->caps.flags & POWER_METER_CAN_TRIP) {
737 		res = register_rw_attrs(resource, trip_attrs);
738 		if (res)
739 			goto error;
740 	}
741 
742 	res = register_ro_attrs(resource, misc_attrs);
743 	if (res)
744 		goto error;
745 
746 	return res;
747 error:
748 	remove_attrs(resource);
749 	return res;
750 }
751 
752 static void free_capabilities(struct acpi_power_meter_resource *resource)
753 {
754 	acpi_string *str;
755 	int i;
756 
757 	str = &resource->model_number;
758 	for (i = 0; i < 3; i++, str++)
759 		kfree(*str);
760 }
761 
762 static int read_capabilities(struct acpi_power_meter_resource *resource)
763 {
764 	int res = 0;
765 	int i;
766 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
767 	struct acpi_buffer state = { 0, NULL };
768 	struct acpi_buffer format = { sizeof("NNNNNNNNNNN"), "NNNNNNNNNNN" };
769 	union acpi_object *pss;
770 	acpi_string *str;
771 	acpi_status status;
772 
773 	status = acpi_evaluate_object(resource->acpi_dev->handle, "_PMC", NULL,
774 				      &buffer);
775 	if (ACPI_FAILURE(status)) {
776 		ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PMC"));
777 		return -ENODEV;
778 	}
779 
780 	pss = buffer.pointer;
781 	if (!pss ||
782 	    pss->type != ACPI_TYPE_PACKAGE ||
783 	    pss->package.count != 14) {
784 		dev_err(&resource->acpi_dev->dev, ACPI_POWER_METER_NAME
785 			"Invalid _PMC data\n");
786 		res = -EFAULT;
787 		goto end;
788 	}
789 
790 	/* Grab all the integer data at once */
791 	state.length = sizeof(struct acpi_power_meter_capabilities);
792 	state.pointer = &resource->caps;
793 
794 	status = acpi_extract_package(pss, &format, &state);
795 	if (ACPI_FAILURE(status)) {
796 		ACPI_EXCEPTION((AE_INFO, status, "Invalid data"));
797 		res = -EFAULT;
798 		goto end;
799 	}
800 
801 	if (resource->caps.units) {
802 		dev_err(&resource->acpi_dev->dev, ACPI_POWER_METER_NAME
803 			"Unknown units %llu.\n",
804 			resource->caps.units);
805 		res = -EINVAL;
806 		goto end;
807 	}
808 
809 	/* Grab the string data */
810 	str = &resource->model_number;
811 
812 	for (i = 11; i < 14; i++) {
813 		union acpi_object *element = &(pss->package.elements[i]);
814 
815 		if (element->type != ACPI_TYPE_STRING) {
816 			res = -EINVAL;
817 			goto error;
818 		}
819 
820 		*str = kzalloc(sizeof(u8) * (element->string.length + 1),
821 			       GFP_KERNEL);
822 		if (!*str) {
823 			res = -ENOMEM;
824 			goto error;
825 		}
826 
827 		strncpy(*str, element->string.pointer, element->string.length);
828 		str++;
829 	}
830 
831 	dev_info(&resource->acpi_dev->dev, "Found ACPI power meter.\n");
832 	goto end;
833 error:
834 	str = &resource->model_number;
835 	for (i = 0; i < 3; i++, str++)
836 		kfree(*str);
837 end:
838 	kfree(buffer.pointer);
839 	return res;
840 }
841 
842 /* Handle ACPI event notifications */
843 static void acpi_power_meter_notify(struct acpi_device *device, u32 event)
844 {
845 	struct acpi_power_meter_resource *resource;
846 	int res;
847 
848 	if (!device || !acpi_driver_data(device))
849 		return;
850 
851 	resource = acpi_driver_data(device);
852 
853 	mutex_lock(&resource->lock);
854 	switch (event) {
855 	case METER_NOTIFY_CONFIG:
856 		free_capabilities(resource);
857 		res = read_capabilities(resource);
858 		if (res)
859 			break;
860 
861 		remove_attrs(resource);
862 		setup_attrs(resource);
863 		break;
864 	case METER_NOTIFY_TRIP:
865 		sysfs_notify(&device->dev.kobj, NULL, POWER_AVERAGE_NAME);
866 		update_meter(resource);
867 		break;
868 	case METER_NOTIFY_CAP:
869 		sysfs_notify(&device->dev.kobj, NULL, POWER_CAP_NAME);
870 		update_cap(resource);
871 		break;
872 	case METER_NOTIFY_INTERVAL:
873 		sysfs_notify(&device->dev.kobj, NULL, POWER_AVG_INTERVAL_NAME);
874 		update_avg_interval(resource);
875 		break;
876 	case METER_NOTIFY_CAPPING:
877 		sysfs_notify(&device->dev.kobj, NULL, POWER_ALARM_NAME);
878 		dev_info(&device->dev, "Capping in progress.\n");
879 		break;
880 	default:
881 		BUG();
882 	}
883 	mutex_unlock(&resource->lock);
884 
885 	acpi_bus_generate_netlink_event(ACPI_POWER_METER_CLASS,
886 					dev_name(&device->dev), event, 0);
887 }
888 
889 static int acpi_power_meter_add(struct acpi_device *device)
890 {
891 	int res;
892 	struct acpi_power_meter_resource *resource;
893 
894 	if (!device)
895 		return -EINVAL;
896 
897 	resource = kzalloc(sizeof(struct acpi_power_meter_resource),
898 			   GFP_KERNEL);
899 	if (!resource)
900 		return -ENOMEM;
901 
902 	resource->sensors_valid = 0;
903 	resource->acpi_dev = device;
904 	mutex_init(&resource->lock);
905 	strcpy(acpi_device_name(device), ACPI_POWER_METER_DEVICE_NAME);
906 	strcpy(acpi_device_class(device), ACPI_POWER_METER_CLASS);
907 	device->driver_data = resource;
908 
909 	free_capabilities(resource);
910 	res = read_capabilities(resource);
911 	if (res)
912 		goto exit_free;
913 
914 	resource->trip[0] = resource->trip[1] = -1;
915 
916 	res = setup_attrs(resource);
917 	if (res)
918 		goto exit_free;
919 
920 	resource->hwmon_dev = hwmon_device_register(&device->dev);
921 	if (IS_ERR(resource->hwmon_dev)) {
922 		res = PTR_ERR(resource->hwmon_dev);
923 		goto exit_remove;
924 	}
925 
926 	res = 0;
927 	goto exit;
928 
929 exit_remove:
930 	remove_attrs(resource);
931 exit_free:
932 	kfree(resource);
933 exit:
934 	return res;
935 }
936 
937 static int acpi_power_meter_remove(struct acpi_device *device, int type)
938 {
939 	struct acpi_power_meter_resource *resource;
940 
941 	if (!device || !acpi_driver_data(device))
942 		return -EINVAL;
943 
944 	resource = acpi_driver_data(device);
945 	hwmon_device_unregister(resource->hwmon_dev);
946 
947 	free_capabilities(resource);
948 	remove_attrs(resource);
949 
950 	kfree(resource);
951 	return 0;
952 }
953 
954 static int acpi_power_meter_resume(struct acpi_device *device)
955 {
956 	struct acpi_power_meter_resource *resource;
957 
958 	if (!device || !acpi_driver_data(device))
959 		return -EINVAL;
960 
961 	resource = acpi_driver_data(device);
962 	free_capabilities(resource);
963 	read_capabilities(resource);
964 
965 	return 0;
966 }
967 
968 static struct acpi_driver acpi_power_meter_driver = {
969 	.name = "power_meter",
970 	.class = ACPI_POWER_METER_CLASS,
971 	.ids = power_meter_ids,
972 	.ops = {
973 		.add = acpi_power_meter_add,
974 		.remove = acpi_power_meter_remove,
975 		.resume = acpi_power_meter_resume,
976 		.notify = acpi_power_meter_notify,
977 		},
978 };
979 
980 /* Module init/exit routines */
981 static int __init enable_cap_knobs(const struct dmi_system_id *d)
982 {
983 	cap_in_hardware = 1;
984 	return 0;
985 }
986 
987 static struct dmi_system_id __initdata pm_dmi_table[] = {
988 	{
989 		enable_cap_knobs, "IBM Active Energy Manager",
990 		{
991 			DMI_MATCH(DMI_SYS_VENDOR, "IBM")
992 		},
993 	},
994 	{}
995 };
996 
997 static int __init acpi_power_meter_init(void)
998 {
999 	int result;
1000 
1001 	if (acpi_disabled)
1002 		return -ENODEV;
1003 
1004 	dmi_check_system(pm_dmi_table);
1005 
1006 	result = acpi_bus_register_driver(&acpi_power_meter_driver);
1007 	if (result < 0)
1008 		return -ENODEV;
1009 
1010 	return 0;
1011 }
1012 
1013 static void __exit acpi_power_meter_exit(void)
1014 {
1015 	acpi_bus_unregister_driver(&acpi_power_meter_driver);
1016 }
1017 
1018 MODULE_AUTHOR("Darrick J. Wong <djwong@us.ibm.com>");
1019 MODULE_DESCRIPTION("ACPI 4.0 power meter driver");
1020 MODULE_LICENSE("GPL");
1021 
1022 module_param(force_cap_on, bool, 0644);
1023 MODULE_PARM_DESC(force_cap_on, "Enable power cap even it is unsafe to do so.");
1024 
1025 module_init(acpi_power_meter_init);
1026 module_exit(acpi_power_meter_exit);
1027