acpi_power_meter.c

   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
  47static int cap_in_hardware;
  48static bool force_cap_on;
  49
  50static DEFINE_MUTEX(acpi_notify_lock);
  51
  52static int can_cap_in_hardware(void)
  53{
  54	return force_cap_on || cap_in_hardware;
  55}
  56
  57static const struct acpi_device_id power_meter_ids[] = {
  58	{"ACPI000D", 0},
  59	{"", 0},
  60};
  61MODULE_DEVICE_TABLE(acpi, power_meter_ids);
  62
  63struct acpi_power_meter_capabilities {
  64	u64		flags;
  65	u64		units;
  66	u64		type;
  67	u64		accuracy;
  68	u64		sampling_time;
  69	u64		min_avg_interval;
  70	u64		max_avg_interval;
  71	u64		hysteresis;
  72	u64		configurable_cap;
  73	u64		min_cap;
  74	u64		max_cap;
  75};
  76
  77struct acpi_power_meter_resource {
  78	struct acpi_device	*acpi_dev;
  79	acpi_bus_id		name;
  80	struct mutex		lock;
  81	struct device		*hwmon_dev;
  82	struct acpi_power_meter_capabilities	caps;
  83	acpi_string		model_number;
  84	acpi_string		serial_number;
  85	acpi_string		oem_info;
  86	u64		power;
  87	u64		cap;
  88	u64		avg_interval;
  89	bool		power_alarm;
  90	int			sensors_valid;
  91	unsigned long		sensors_last_updated;
  92#define POWER_METER_TRIP_AVERAGE_MIN_IDX	0
  93#define POWER_METER_TRIP_AVERAGE_MAX_IDX	1
  94	s64			trip[2];
  95	int			num_domain_devices;
  96	struct acpi_device	**domain_devices;
  97	struct kobject		*holders_dir;
  98};
  99
 100/* Averaging interval */
 101static int update_avg_interval(struct acpi_power_meter_resource *resource)
 102{
 103	unsigned long long data;
 104	acpi_status status;
 105
 106	status = acpi_evaluate_integer(resource->acpi_dev->handle, "_GAI",
 107				       NULL, &data);
 108	if (ACPI_FAILURE(status)) {
 109		acpi_evaluation_failure_warn(resource->acpi_dev->handle, "_GAI",
 110					     status);
 111		return -ENODEV;
 112	}
 113
 114	resource->avg_interval = data;
 115	return 0;
 116}
 117
 118/* Cap functions */
 119static int update_cap(struct acpi_power_meter_resource *resource)
 120{
 121	unsigned long long data;
 122	acpi_status status;
 123
 124	status = acpi_evaluate_integer(resource->acpi_dev->handle, "_GHL",
 125				       NULL, &data);
 126	if (ACPI_FAILURE(status)) {
 127		acpi_evaluation_failure_warn(resource->acpi_dev->handle, "_GHL",
 128					     status);
 129		return -ENODEV;
 130	}
 131
 132	resource->cap = data;
 133	return 0;
 134}
 135
 136/* Power meter trip points */
 137static int set_acpi_trip(struct acpi_power_meter_resource *resource)
 138{
 139	union acpi_object arg_objs[] = {
 140		{ACPI_TYPE_INTEGER},
 141		{ACPI_TYPE_INTEGER}
 142	};
 143	struct acpi_object_list args = { 2, arg_objs };
 144	unsigned long long data;
 145	acpi_status status;
 146
 147	/* Both trip levels must be set */
 148	if (resource->trip[0] < 0 || resource->trip[1] < 0)
 149		return 0;
 150
 151	/* This driver stores min, max; ACPI wants max, min. */
 152	arg_objs[0].integer.value = resource->trip[1];
 153	arg_objs[1].integer.value = resource->trip[0];
 154
 155	status = acpi_evaluate_integer(resource->acpi_dev->handle, "_PTP",
 156				       &args, &data);
 157	if (ACPI_FAILURE(status)) {
 158		acpi_evaluation_failure_warn(resource->acpi_dev->handle, "_PTP",
 159					     status);
 160		return -EINVAL;
 161	}
 162
 163	/* _PTP returns 0 on success, nonzero otherwise */
 164	if (data)
 165		return -EINVAL;
 166
 167	return 0;
 168}
 169
 170/* Power meter */
 171static int update_meter(struct acpi_power_meter_resource *resource)
 172{
 173	unsigned long long data;
 174	acpi_status status;
 175	unsigned long local_jiffies = jiffies;
 176
 177	if (time_before(local_jiffies, resource->sensors_last_updated +
 178			msecs_to_jiffies(resource->caps.sampling_time)) &&
 179			resource->sensors_valid)
 180		return 0;
 181
 182	status = acpi_evaluate_integer(resource->acpi_dev->handle, "_PMM",
 183				       NULL, &data);
 184	if (ACPI_FAILURE(status)) {
 185		acpi_evaluation_failure_warn(resource->acpi_dev->handle, "_PMM",
 186					     status);
 187		return -ENODEV;
 188	}
 189
 190	resource->power = data;
 191	resource->sensors_valid = 1;
 192	resource->sensors_last_updated = jiffies;
 193	return 0;
 194}
 195
 196/* Read power domain data */
 197static void remove_domain_devices(struct acpi_power_meter_resource *resource)
 198{
 199	int i;
 200
 201	if (!resource->num_domain_devices)
 202		return;
 203
 204	for (i = 0; i < resource->num_domain_devices; i++) {
 205		struct acpi_device *obj = resource->domain_devices[i];
 206
 207		if (!obj)
 208			continue;
 209
 210		sysfs_remove_link(resource->holders_dir,
 211				  kobject_name(&obj->dev.kobj));
 212		acpi_dev_put(obj);
 213	}
 214
 215	kfree(resource->domain_devices);
 216	kobject_put(resource->holders_dir);
 217	resource->num_domain_devices = 0;
 218}
 219
 220static int read_domain_devices(struct acpi_power_meter_resource *resource)
 221{
 222	int res = 0;
 223	int i;
 224	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 225	union acpi_object *pss;
 226	acpi_status status;
 227
 228	status = acpi_evaluate_object(resource->acpi_dev->handle, "_PMD", NULL,
 229				      &buffer);
 230	if (ACPI_FAILURE(status)) {
 231		acpi_evaluation_failure_warn(resource->acpi_dev->handle, "_PMD",
 232					     status);
 233		return -ENODEV;
 234	}
 235
 236	pss = buffer.pointer;
 237	if (!pss ||
 238	    pss->type != ACPI_TYPE_PACKAGE) {
 239		dev_err(&resource->acpi_dev->dev, ACPI_POWER_METER_NAME
 240			"Invalid _PMD data\n");
 241		res = -EFAULT;
 242		goto end;
 243	}
 244
 245	if (!pss->package.count)
 246		goto end;
 247
 248	resource->domain_devices = kcalloc(pss->package.count,
 249					   sizeof(struct acpi_device *),
 250					   GFP_KERNEL);
 251	if (!resource->domain_devices) {
 252		res = -ENOMEM;
 253		goto end;
 254	}
 255
 256	resource->holders_dir = kobject_create_and_add("measures",
 257						       &resource->acpi_dev->dev.kobj);
 258	if (!resource->holders_dir) {
 259		res = -ENOMEM;
 260		goto exit_free;
 261	}
 262
 263	resource->num_domain_devices = pss->package.count;
 264
 265	for (i = 0; i < pss->package.count; i++) {
 266		struct acpi_device *obj;
 267		union acpi_object *element = &pss->package.elements[i];
 268
 269		/* Refuse non-references */
 270		if (element->type != ACPI_TYPE_LOCAL_REFERENCE)
 271			continue;
 272
 273		/* Create a symlink to domain objects */
 274		obj = acpi_get_acpi_dev(element->reference.handle);
 275		resource->domain_devices[i] = obj;
 276		if (!obj)
 277			continue;
 278
 279		res = sysfs_create_link(resource->holders_dir, &obj->dev.kobj,
 280					kobject_name(&obj->dev.kobj));
 281		if (res) {
 282			acpi_dev_put(obj);
 283			resource->domain_devices[i] = NULL;
 284		}
 285	}
 286
 287	res = 0;
 288	goto end;
 289
 290exit_free:
 291	kfree(resource->domain_devices);
 292end:
 293	kfree(buffer.pointer);
 294	return res;
 295}
 296
 297static int set_trip(struct acpi_power_meter_resource *resource, u16 trip_idx,
 298		    unsigned long trip)
 299{
 300	unsigned long trip_bk;
 301	int ret;
 302
 303	trip = DIV_ROUND_CLOSEST(trip, 1000);
 304	trip_bk = resource->trip[trip_idx];
 305
 306	resource->trip[trip_idx] = trip;
 307	ret = set_acpi_trip(resource);
 308	if (ret) {
 309		dev_err(&resource->acpi_dev->dev, "set %s failed.\n",
 310			(trip_idx == POWER_METER_TRIP_AVERAGE_MIN_IDX) ?
 311			 "power1_average_min" : "power1_average_max");
 312		resource->trip[trip_idx] = trip_bk;
 313	}
 314
 315	return ret;
 316}
 317
 318static int set_cap(struct acpi_power_meter_resource *resource,
 319		   unsigned long cap)
 320{
 321	union acpi_object arg0 = { ACPI_TYPE_INTEGER };
 322	struct acpi_object_list args = { 1, &arg0 };
 323	unsigned long long data;
 324	acpi_status status;
 325
 326	cap = DIV_ROUND_CLOSEST(cap, 1000);
 327	if (cap > resource->caps.max_cap || cap < resource->caps.min_cap)
 328		return -EINVAL;
 329
 330	arg0.integer.value = cap;
 331	status = acpi_evaluate_integer(resource->acpi_dev->handle, "_SHL",
 332				       &args, &data);
 333	if (ACPI_FAILURE(status)) {
 334		acpi_evaluation_failure_warn(resource->acpi_dev->handle, "_SHL",
 335					     status);
 336		return -EINVAL;
 337	}
 338	resource->cap = cap;
 339
 340	/* _SHL returns 0 on success, nonzero otherwise */
 341	if (data)
 342		return -EINVAL;
 343
 344	return 0;
 345}
 346
 347static int set_avg_interval(struct acpi_power_meter_resource *resource,
 348			    unsigned long val)
 349{
 350	union acpi_object arg0 = { ACPI_TYPE_INTEGER };
 351	struct acpi_object_list args = { 1, &arg0 };
 352	unsigned long long data;
 353	acpi_status status;
 354
 355	if (val > resource->caps.max_avg_interval ||
 356	    val < resource->caps.min_avg_interval)
 357		return -EINVAL;
 358
 359	arg0.integer.value = val;
 360	status = acpi_evaluate_integer(resource->acpi_dev->handle, "_PAI",
 361				       &args, &data);
 362	if (ACPI_FAILURE(status)) {
 363		acpi_evaluation_failure_warn(resource->acpi_dev->handle, "_PAI",
 364					     status);
 365		return -EINVAL;
 366	}
 367	resource->avg_interval = val;
 368
 369	/* _PAI returns 0 on success, nonzero otherwise */
 370	if (data)
 371		return -EINVAL;
 372
 373	return 0;
 374}
 375
 376static int get_power_alarm_state(struct acpi_power_meter_resource *resource,
 377				 long *val)
 378{
 379	int ret;
 380
 381	ret = update_meter(resource);
 382	if (ret)
 383		return ret;
 384
 385	/* need to update cap if not to support the notification. */
 386	if (!(resource->caps.flags & POWER_METER_CAN_NOTIFY)) {
 387		ret = update_cap(resource);
 388		if (ret)
 389			return ret;
 390		resource->power_alarm = resource->power > resource->cap;
 391		*val = resource->power_alarm;
 392	} else {
 393		*val = resource->power_alarm || resource->power > resource->cap;
 394		resource->power_alarm = resource->power > resource->cap;
 395	}
 396
 397	return 0;
 398}
 399
 400static umode_t power_meter_is_visible(const void *data,
 401				      enum hwmon_sensor_types type,
 402				      u32 attr, int channel)
 403{
 404	const struct acpi_power_meter_resource *res = data;
 405
 406	if (type != hwmon_power)
 407		return 0;
 408
 409	switch (attr) {
 410	case hwmon_power_average:
 411	case hwmon_power_average_interval_min:
 412	case hwmon_power_average_interval_max:
 413		if (res->caps.flags & POWER_METER_CAN_MEASURE)
 414			return 0444;
 415		break;
 416	case hwmon_power_average_interval:
 417		if (res->caps.flags & POWER_METER_CAN_MEASURE)
 418			return 0644;
 419		break;
 420	case hwmon_power_cap_min:
 421	case hwmon_power_cap_max:
 422	case hwmon_power_alarm:
 423		if (res->caps.flags & POWER_METER_CAN_CAP && can_cap_in_hardware())
 424			return 0444;
 425		break;
 426	case hwmon_power_cap:
 427		if (res->caps.flags & POWER_METER_CAN_CAP && can_cap_in_hardware()) {
 428			if (res->caps.configurable_cap)
 429				return 0644;
 430			else
 431				return 0444;
 432		}
 433		break;
 434	default:
 435		break;
 436	}
 437
 438	return 0;
 439}
 440
 441static int power_meter_read(struct device *dev, enum hwmon_sensor_types type,
 442			    u32 attr, int channel, long *val)
 443{
 444	struct acpi_power_meter_resource *res = dev_get_drvdata(dev);
 445	int ret = 0;
 446
 447	if (type != hwmon_power)
 448		return -EINVAL;
 449
 450	guard(mutex)(&res->lock);
 451
 452	switch (attr) {
 453	case hwmon_power_average:
 454		ret = update_meter(res);
 455		if (ret)
 456			return ret;
 457		if (res->power == UNKNOWN_POWER)
 458			return -ENODATA;
 459		*val = res->power * 1000;
 460		break;
 461	case hwmon_power_average_interval_min:
 462		*val = res->caps.min_avg_interval;
 463		break;
 464	case hwmon_power_average_interval_max:
 465		*val = res->caps.max_avg_interval;
 466		break;
 467	case hwmon_power_average_interval:
 468		ret = update_avg_interval(res);
 469		if (ret)
 470			return ret;
 471		*val = (res)->avg_interval;
 472		break;
 473	case hwmon_power_cap_min:
 474		*val = res->caps.min_cap * 1000;
 475		break;
 476	case hwmon_power_cap_max:
 477		*val = res->caps.max_cap * 1000;
 478		break;
 479	case hwmon_power_alarm:
 480		ret = get_power_alarm_state(res, val);
 481		if (ret)
 482			return ret;
 483		break;
 484	case hwmon_power_cap:
 485		ret = update_cap(res);
 486		if (ret)
 487			return ret;
 488		*val = res->cap * 1000;
 489		break;
 490	default:
 491		break;
 492	}
 493
 494	return 0;
 495}
 496
 497static int power_meter_write(struct device *dev, enum hwmon_sensor_types type,
 498			     u32 attr, int channel, long val)
 499{
 500	struct acpi_power_meter_resource *res = dev_get_drvdata(dev);
 501	int ret;
 502
 503	if (type != hwmon_power)
 504		return -EINVAL;
 505
 506	guard(mutex)(&res->lock);
 507	switch (attr) {
 508	case hwmon_power_cap:
 509		ret = set_cap(res, val);
 510		break;
 511	case hwmon_power_average_interval:
 512		ret = set_avg_interval(res, val);
 513		break;
 514	default:
 515		ret = -EOPNOTSUPP;
 516	}
 517
 518	return ret;
 519}
 520
 521static const struct hwmon_channel_info * const power_meter_info[] = {
 522	HWMON_CHANNEL_INFO(power, HWMON_P_AVERAGE |
 523		HWMON_P_AVERAGE_INTERVAL | HWMON_P_AVERAGE_INTERVAL_MIN |
 524		HWMON_P_AVERAGE_INTERVAL_MAX | HWMON_P_CAP | HWMON_P_CAP_MIN |
 525		HWMON_P_CAP_MAX | HWMON_P_ALARM),
 526	NULL
 527};
 528
 529static const struct hwmon_ops power_meter_ops = {
 530	.is_visible = power_meter_is_visible,
 531	.read = power_meter_read,
 532	.write = power_meter_write,
 533};
 534
 535static const struct hwmon_chip_info power_meter_chip_info = {
 536	.ops = &power_meter_ops,
 537	.info = power_meter_info,
 538};
 539
 540static ssize_t power1_average_max_store(struct device *dev,
 541					struct device_attribute *attr,
 542					const char *buf, size_t count)
 543{
 544	struct acpi_power_meter_resource *res = dev_get_drvdata(dev);
 545	unsigned long trip;
 546	int ret;
 547
 548	ret = kstrtoul(buf, 10, &trip);
 549	if (ret)
 550		return ret;
 551
 552	mutex_lock(&res->lock);
 553	ret = set_trip(res, POWER_METER_TRIP_AVERAGE_MAX_IDX, trip);
 554	mutex_unlock(&res->lock);
 555
 556	return ret == 0 ? count : ret;
 557}
 558
 559static ssize_t power1_average_min_store(struct device *dev,
 560					struct device_attribute *attr,
 561					const char *buf, size_t count)
 562{
 563	struct acpi_power_meter_resource *res = dev_get_drvdata(dev);
 564	unsigned long trip;
 565	int ret;
 566
 567	ret = kstrtoul(buf, 10, &trip);
 568	if (ret)
 569		return ret;
 570
 571	mutex_lock(&res->lock);
 572	ret = set_trip(res, POWER_METER_TRIP_AVERAGE_MIN_IDX, trip);
 573	mutex_unlock(&res->lock);
 574
 575	return ret == 0 ? count : ret;
 576}
 577
 578static ssize_t power1_average_min_show(struct device *dev,
 579				       struct device_attribute *attr, char *buf)
 580{
 581	struct acpi_power_meter_resource *res = dev_get_drvdata(dev);
 582
 583	if (res->trip[POWER_METER_TRIP_AVERAGE_MIN_IDX] < 0)
 584		return sysfs_emit(buf, "unknown\n");
 585
 586	return sysfs_emit(buf, "%lld\n",
 587			  res->trip[POWER_METER_TRIP_AVERAGE_MIN_IDX] * 1000);
 588}
 589
 590static ssize_t power1_average_max_show(struct device *dev,
 591				       struct device_attribute *attr, char *buf)
 592{
 593	struct acpi_power_meter_resource *res = dev_get_drvdata(dev);
 594
 595	if (res->trip[POWER_METER_TRIP_AVERAGE_MAX_IDX] < 0)
 596		return sysfs_emit(buf, "unknown\n");
 597
 598	return sysfs_emit(buf, "%lld\n",
 599			  res->trip[POWER_METER_TRIP_AVERAGE_MAX_IDX] * 1000);
 600}
 601
 602static ssize_t power1_cap_hyst_show(struct device *dev,
 603				    struct device_attribute *attr, char *buf)
 604{
 605	struct acpi_power_meter_resource *res = dev_get_drvdata(dev);
 606
 607	if (res->caps.hysteresis == UNKNOWN_HYSTERESIS)
 608		return sysfs_emit(buf, "unknown\n");
 609
 610	return sysfs_emit(buf, "%llu\n", res->caps.hysteresis * 1000);
 611}
 612
 613static ssize_t power1_accuracy_show(struct device *dev,
 614				    struct device_attribute *attr,
 615				    char *buf)
 616{
 617	struct acpi_power_meter_resource *res = dev_get_drvdata(dev);
 618	unsigned int acc = res->caps.accuracy;
 619
 620	return sysfs_emit(buf, "%u.%u%%\n", acc / 1000, acc % 1000);
 621}
 622
 623static ssize_t power1_is_battery_show(struct device *dev,
 624				      struct device_attribute *attr,
 625				      char *buf)
 626{
 627	struct acpi_power_meter_resource *res = dev_get_drvdata(dev);
 628
 629	return sysfs_emit(buf, "%u\n",
 630			  res->caps.flags & POWER_METER_IS_BATTERY ? 1 : 0);
 631}
 632
 633static ssize_t power1_model_number_show(struct device *dev,
 634					struct device_attribute *attr,
 635					char *buf)
 636{
 637	struct acpi_power_meter_resource *res = dev_get_drvdata(dev);
 638
 639	return sysfs_emit(buf, "%s\n", res->model_number);
 640}
 641
 642static ssize_t power1_oem_info_show(struct device *dev,
 643				    struct device_attribute *attr,
 644				    char *buf)
 645{
 646	struct acpi_power_meter_resource *res = dev_get_drvdata(dev);
 647
 648	return sysfs_emit(buf, "%s\n", res->oem_info);
 649}
 650
 651static ssize_t power1_serial_number_show(struct device *dev,
 652					 struct device_attribute *attr,
 653					 char *buf)
 654{
 655	struct acpi_power_meter_resource *res = dev_get_drvdata(dev);
 656
 657	return sysfs_emit(buf, "%s\n", res->serial_number);
 658}
 659
 660/* depend on POWER_METER_CAN_TRIP */
 661static DEVICE_ATTR_RW(power1_average_max);
 662static DEVICE_ATTR_RW(power1_average_min);
 663
 664/* depend on POWER_METER_CAN_CAP */
 665static DEVICE_ATTR_RO(power1_cap_hyst);
 666
 667/* depend on POWER_METER_CAN_MEASURE */
 668static DEVICE_ATTR_RO(power1_accuracy);
 669static DEVICE_ATTR_RO(power1_is_battery);
 670
 671static DEVICE_ATTR_RO(power1_model_number);
 672static DEVICE_ATTR_RO(power1_oem_info);
 673static DEVICE_ATTR_RO(power1_serial_number);
 674
 675static umode_t power_extra_is_visible(struct kobject *kobj,
 676				      struct attribute *attr, int idx)
 677{
 678	struct device *dev = kobj_to_dev(kobj);
 679	struct acpi_power_meter_resource *res = dev_get_drvdata(dev);
 680
 681	if (attr == &dev_attr_power1_is_battery.attr ||
 682	    attr == &dev_attr_power1_accuracy.attr) {
 683		if ((res->caps.flags & POWER_METER_CAN_MEASURE) == 0)
 684			return 0;
 685	}
 686
 687	if (attr == &dev_attr_power1_cap_hyst.attr) {
 688		if ((res->caps.flags & POWER_METER_CAN_CAP) == 0) {
 689			return 0;
 690		} else if (!can_cap_in_hardware()) {
 691			dev_warn(&res->acpi_dev->dev,
 692				 "Ignoring unsafe software power cap!\n");
 693			return 0;
 694		}
 695	}
 696
 697	if (attr == &dev_attr_power1_average_max.attr ||
 698	    attr == &dev_attr_power1_average_min.attr) {
 699		if ((res->caps.flags & POWER_METER_CAN_TRIP) == 0)
 700			return 0;
 701	}
 702
 703	return attr->mode;
 704}
 705
 706static struct attribute *power_extra_attrs[] = {
 707	&dev_attr_power1_average_max.attr,
 708	&dev_attr_power1_average_min.attr,
 709	&dev_attr_power1_cap_hyst.attr,
 710	&dev_attr_power1_accuracy.attr,
 711	&dev_attr_power1_is_battery.attr,
 712	&dev_attr_power1_model_number.attr,
 713	&dev_attr_power1_oem_info.attr,
 714	&dev_attr_power1_serial_number.attr,
 715	NULL
 716};
 717
 718static const struct attribute_group power_extra_group = {
 719	.attrs = power_extra_attrs,
 720	.is_visible = power_extra_is_visible,
 721};
 722
 723__ATTRIBUTE_GROUPS(power_extra);
 724
 725static void free_capabilities(struct acpi_power_meter_resource *resource)
 726{
 727	acpi_string *str;
 728	int i;
 729
 730	str = &resource->model_number;
 731	for (i = 0; i < 3; i++, str++) {
 732		kfree(*str);
 733		*str = NULL;
 734	}
 735}
 736
 737static int read_capabilities(struct acpi_power_meter_resource *resource)
 738{
 739	int res = 0;
 740	int i;
 741	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 742	struct acpi_buffer state = { 0, NULL };
 743	struct acpi_buffer format = { sizeof("NNNNNNNNNNN"), "NNNNNNNNNNN" };
 744	union acpi_object *pss;
 745	acpi_string *str;
 746	acpi_status status;
 747
 748	status = acpi_evaluate_object(resource->acpi_dev->handle, "_PMC", NULL,
 749				      &buffer);
 750	if (ACPI_FAILURE(status)) {
 751		acpi_evaluation_failure_warn(resource->acpi_dev->handle, "_PMC",
 752					     status);
 753		return -ENODEV;
 754	}
 755
 756	pss = buffer.pointer;
 757	if (!pss ||
 758	    pss->type != ACPI_TYPE_PACKAGE ||
 759	    pss->package.count != 14) {
 760		dev_err(&resource->acpi_dev->dev, ACPI_POWER_METER_NAME
 761			"Invalid _PMC data\n");
 762		res = -EFAULT;
 763		goto end;
 764	}
 765
 766	/* Grab all the integer data at once */
 767	state.length = sizeof(struct acpi_power_meter_capabilities);
 768	state.pointer = &resource->caps;
 769
 770	status = acpi_extract_package(pss, &format, &state);
 771	if (ACPI_FAILURE(status)) {
 772		dev_err(&resource->acpi_dev->dev, ACPI_POWER_METER_NAME
 773			"_PMC package parsing failed: %s\n",
 774			acpi_format_exception(status));
 775		res = -EFAULT;
 776		goto end;
 777	}
 778
 779	if (resource->caps.units) {
 780		dev_err(&resource->acpi_dev->dev, ACPI_POWER_METER_NAME
 781			"Unknown units %llu.\n",
 782			resource->caps.units);
 783		res = -EINVAL;
 784		goto end;
 785	}
 786
 787	/* Grab the string data */
 788	str = &resource->model_number;
 789
 790	for (i = 11; i < 14; i++) {
 791		union acpi_object *element = &pss->package.elements[i];
 792
 793		if (element->type != ACPI_TYPE_STRING) {
 794			res = -EINVAL;
 795			goto error;
 796		}
 797
 798		*str = kmemdup_nul(element->string.pointer, element->string.length,
 799				   GFP_KERNEL);
 800		if (!*str) {
 801			res = -ENOMEM;
 802			goto error;
 803		}
 804
 805		str++;
 806	}
 807
 808	dev_info(&resource->acpi_dev->dev, "Found ACPI power meter.\n");
 809	goto end;
 810error:
 811	free_capabilities(resource);
 812end:
 813	kfree(buffer.pointer);
 814	return res;
 815}
 816
 817/* Handle ACPI event notifications */
 818static void acpi_power_meter_notify(struct acpi_device *device, u32 event)
 819{
 820	struct acpi_power_meter_resource *resource;
 821	int res;
 822
 823	if (!device || !acpi_driver_data(device))
 824		return;
 825
 826	resource = acpi_driver_data(device);
 827
 828	guard(mutex)(&acpi_notify_lock);
 829
 830	switch (event) {
 831	case METER_NOTIFY_CONFIG:
 832		if (!IS_ERR(resource->hwmon_dev))
 833			hwmon_device_unregister(resource->hwmon_dev);
 834
 835		mutex_lock(&resource->lock);
 836
 837		free_capabilities(resource);
 838		remove_domain_devices(resource);
 839		res = read_capabilities(resource);
 840		if (res)
 841			dev_err_once(&device->dev, "read capabilities failed.\n");
 842		res = read_domain_devices(resource);
 843		if (res && res != -ENODEV)
 844			dev_err_once(&device->dev, "read domain devices failed.\n");
 845
 846		mutex_unlock(&resource->lock);
 847
 848		resource->hwmon_dev =
 849			hwmon_device_register_with_info(&device->dev,
 850							ACPI_POWER_METER_NAME,
 851							resource,
 852							&power_meter_chip_info,
 853							power_extra_groups);
 854		if (IS_ERR(resource->hwmon_dev))
 855			dev_err_once(&device->dev, "register hwmon device failed.\n");
 856
 857		break;
 858	case METER_NOTIFY_TRIP:
 859		sysfs_notify(&device->dev.kobj, NULL, POWER_AVERAGE_NAME);
 860		break;
 861	case METER_NOTIFY_CAP:
 862		mutex_lock(&resource->lock);
 863		res = update_cap(resource);
 864		if (res)
 865			dev_err_once(&device->dev, "update cap failed when capping value is changed.\n");
 866		mutex_unlock(&resource->lock);
 867		sysfs_notify(&device->dev.kobj, NULL, POWER_CAP_NAME);
 868		break;
 869	case METER_NOTIFY_INTERVAL:
 870		sysfs_notify(&device->dev.kobj, NULL, POWER_AVG_INTERVAL_NAME);
 871		break;
 872	case METER_NOTIFY_CAPPING:
 873		mutex_lock(&resource->lock);
 874		resource->power_alarm = true;
 875		mutex_unlock(&resource->lock);
 876		sysfs_notify(&device->dev.kobj, NULL, POWER_ALARM_NAME);
 877		dev_info(&device->dev, "Capping in progress.\n");
 878		break;
 879	default:
 880		WARN(1, "Unexpected event %d\n", event);
 881		break;
 882	}
 883
 884	acpi_bus_generate_netlink_event(ACPI_POWER_METER_CLASS,
 885					dev_name(&device->dev), event, 0);
 886}
 887
 888static int acpi_power_meter_add(struct acpi_device *device)
 889{
 890	int res;
 891	struct acpi_power_meter_resource *resource;
 892
 893	if (!device)
 894		return -EINVAL;
 895
 896	resource = kzalloc(sizeof(*resource), GFP_KERNEL);
 897	if (!resource)
 898		return -ENOMEM;
 899
 900	resource->sensors_valid = 0;
 901	resource->acpi_dev = device;
 902	mutex_init(&resource->lock);
 903	strcpy(acpi_device_name(device), ACPI_POWER_METER_DEVICE_NAME);
 904	strcpy(acpi_device_class(device), ACPI_POWER_METER_CLASS);
 905	device->driver_data = resource;
 906
 907#if IS_REACHABLE(CONFIG_ACPI_IPMI)
 908	/*
 909	 * On Dell systems several methods of acpi_power_meter access
 910	 * variables in IPMI region, so wait until IPMI space handler is
 911	 * installed by acpi_ipmi and also wait until SMI is selected to make
 912	 * the space handler fully functional.
 913	 */
 914	if (dmi_match(DMI_SYS_VENDOR, "Dell Inc.")) {
 915		struct acpi_device *ipi_device = acpi_dev_get_first_match_dev("IPI0001", NULL, -1);
 916
 917		if (ipi_device && acpi_wait_for_acpi_ipmi())
 918			dev_warn(&device->dev, "Waiting for ACPI IPMI timeout");
 919		acpi_dev_put(ipi_device);
 920	}
 921#endif
 922
 923	res = read_capabilities(resource);
 924	if (res)
 925		goto exit_free;
 926
 927	resource->trip[0] = -1;
 928	resource->trip[1] = -1;
 929
 930	/* _PMD method is optional. */
 931	res = read_domain_devices(resource);
 932	if (res && res != -ENODEV)
 933		goto exit_free_capability;
 934
 935	resource->hwmon_dev =
 936		hwmon_device_register_with_info(&device->dev,
 937						ACPI_POWER_METER_NAME, resource,
 938						&power_meter_chip_info,
 939						power_extra_groups);
 940	if (IS_ERR(resource->hwmon_dev)) {
 941		res = PTR_ERR(resource->hwmon_dev);
 942		goto exit_remove;
 943	}
 944
 945	res = 0;
 946	goto exit;
 947
 948exit_remove:
 949	remove_domain_devices(resource);
 950exit_free_capability:
 951	free_capabilities(resource);
 952exit_free:
 953	kfree(resource);
 954exit:
 955	return res;
 956}
 957
 958static void acpi_power_meter_remove(struct acpi_device *device)
 959{
 960	struct acpi_power_meter_resource *resource;
 961
 962	if (!device || !acpi_driver_data(device))
 963		return;
 964
 965	resource = acpi_driver_data(device);
 966	if (!IS_ERR(resource->hwmon_dev))
 967		hwmon_device_unregister(resource->hwmon_dev);
 968
 969	remove_domain_devices(resource);
 970	free_capabilities(resource);
 971
 972	kfree(resource);
 973}
 974
 975static int acpi_power_meter_resume(struct device *dev)
 976{
 977	struct acpi_power_meter_resource *resource;
 978
 979	if (!dev)
 980		return -EINVAL;
 981
 982	resource = acpi_driver_data(to_acpi_device(dev));
 983	if (!resource)
 984		return -EINVAL;
 985
 986	free_capabilities(resource);
 987	read_capabilities(resource);
 988
 989	return 0;
 990}
 991
 992static DEFINE_SIMPLE_DEV_PM_OPS(acpi_power_meter_pm, NULL,
 993				acpi_power_meter_resume);
 994
 995static struct acpi_driver acpi_power_meter_driver = {
 996	.name = "power_meter",
 997	.class = ACPI_POWER_METER_CLASS,
 998	.ids = power_meter_ids,
 999	.ops = {
1000		.add = acpi_power_meter_add,
1001		.remove = acpi_power_meter_remove,
1002		.notify = acpi_power_meter_notify,
1003		},
1004	.drv.pm = pm_sleep_ptr(&acpi_power_meter_pm),
1005};
1006
1007/* Module init/exit routines */
1008static int __init enable_cap_knobs(const struct dmi_system_id *d)
1009{
1010	cap_in_hardware = 1;
1011	return 0;
1012}
1013
1014static const struct dmi_system_id pm_dmi_table[] __initconst = {
1015	{
1016		enable_cap_knobs, "IBM Active Energy Manager",
1017		{
1018			DMI_MATCH(DMI_SYS_VENDOR, "IBM")
1019		},
1020	},
1021	{}
1022};
1023
1024static int __init acpi_power_meter_init(void)
1025{
1026	int result;
1027
1028	if (acpi_disabled)
1029		return -ENODEV;
1030
1031	dmi_check_system(pm_dmi_table);
1032
1033	result = acpi_bus_register_driver(&acpi_power_meter_driver);
1034	if (result < 0)
1035		return result;
1036
1037	return 0;
1038}
1039
1040static void __exit acpi_power_meter_exit(void)
1041{
1042	acpi_bus_unregister_driver(&acpi_power_meter_driver);
1043}
1044
1045MODULE_AUTHOR("Darrick J. Wong <darrick.wong@oracle.com>");
1046MODULE_DESCRIPTION("ACPI 4.0 power meter driver");
1047MODULE_LICENSE("GPL");
1048
1049module_param(force_cap_on, bool, 0644);
1050MODULE_PARM_DESC(force_cap_on, "Enable power cap even it is unsafe to do so.");
1051
1052module_init(acpi_power_meter_init);
1053module_exit(acpi_power_meter_exit);