drivers/hwmon/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 ACPI_MODULE_NAME(ACPI_POWER_METER_NAME);
  24 #define ACPI_POWER_METER_DEVICE_NAME    "Power Meter"
  25 #define ACPI_POWER_METER_CLASS          "pwr_meter_resource"
  26
  27 #define NUM_SENSORS                     17
  28
  29 #define POWER_METER_CAN_MEASURE (1 << 0)
  30 #define POWER_METER_CAN_TRIP    (1 << 1)
  31 #define POWER_METER_CAN_CAP     (1 << 2)
  32 #define POWER_METER_CAN_NOTIFY  (1 << 3)
  33 #define POWER_METER_IS_BATTERY  (1 << 8)
  34 #define UNKNOWN_HYSTERESIS      0xFFFFFFFF
  35
  36 #define METER_NOTIFY_CONFIG     0x80
  37 #define METER_NOTIFY_TRIP       0x81
  38 #define METER_NOTIFY_CAP        0x82
  39 #define METER_NOTIFY_CAPPING    0x83
  40 #define METER_NOTIFY_INTERVAL   0x84
  41
  42 #define POWER_AVERAGE_NAME      "power1_average"
  43 #define POWER_CAP_NAME          "power1_cap"
  44 #define POWER_AVG_INTERVAL_NAME "power1_average_interval"
  45 #define POWER_ALARM_NAME        "power1_alarm"
  46
  47 static int cap_in_hardware;
  48 static bool force_cap_on;
  49
  50 static int can_cap_in_hardware(void)
  51 {
  52         return force_cap_on || cap_in_hardware;
  53 }
  54
  55 static const struct acpi_device_id power_meter_ids[] = {
  56         {"ACPI000D", 0},
  57         {"", 0},
  58 };
  59 MODULE_DEVICE_TABLE(acpi, power_meter_ids);
  60
  61 struct acpi_power_meter_capabilities {
  62         u64             flags;
  63         u64             units;
  64         u64             type;
  65         u64             accuracy;
  66         u64             sampling_time;
  67         u64             min_avg_interval;
  68         u64             max_avg_interval;
  69         u64             hysteresis;
  70         u64             configurable_cap;
  71         u64             min_cap;
  72         u64             max_cap;
  73 };
  74
  75 struct acpi_power_meter_resource {
  76         struct acpi_device      *acpi_dev;
  77         acpi_bus_id             name;
  78         struct mutex            lock;
  79         struct device           *hwmon_dev;
  80         struct acpi_power_meter_capabilities    caps;
  81         acpi_string             model_number;
  82         acpi_string             serial_number;
  83         acpi_string             oem_info;
  84         u64             power;
  85         u64             cap;
  86         u64             avg_interval;
  87         int                     sensors_valid;
  88         unsigned long           sensors_last_updated;
  89         struct sensor_device_attribute  sensors[NUM_SENSORS];
  90         int                     num_sensors;
  91         s64                     trip[2];
  92         int                     num_domain_devices;
  93         struct acpi_device      **domain_devices;
  94         struct kobject          *holders_dir;
  95 };
  96
  97 struct sensor_template {
  98         char *label;
  99         ssize_t (*show)(struct device *dev,
 100                         struct device_attribute *devattr,
 101                         char *buf);
 102         ssize_t (*set)(struct device *dev,
 103                        struct device_attribute *devattr,
 104                        const char *buf, size_t count);
 105         int index;
 106 };
 107
 108 /* Averaging interval */
 109 static int update_avg_interval(struct acpi_power_meter_resource *resource)
 110 {
 111         unsigned long long data;
 112         acpi_status status;
 113
 114         status = acpi_evaluate_integer(resource->acpi_dev->handle, "_GAI",
 115                                        NULL, &data);
 116         if (ACPI_FAILURE(status)) {
 117                 ACPI_EXCEPTION((AE_INFO, status, "Evaluating _GAI"));
 118                 return -ENODEV;
 119         }
 120
 121         resource->avg_interval = data;
 122         return 0;
 123 }
 124
 125 static ssize_t show_avg_interval(struct device *dev,
 126                                  struct device_attribute *devattr,
 127                                  char *buf)
 128 {
 129         struct acpi_device *acpi_dev = to_acpi_device(dev);
 130         struct acpi_power_meter_resource *resource = acpi_dev->driver_data;
 131
 132         mutex_lock(&resource->lock);
 133         update_avg_interval(resource);
 134         mutex_unlock(&resource->lock);
 135
 136         return sprintf(buf, "%llu\n", resource->avg_interval);
 137 }
 138
 139 static ssize_t set_avg_interval(struct device *dev,
 140                                 struct device_attribute *devattr,
 141                                 const char *buf, size_t count)
 142 {
 143         struct acpi_device *acpi_dev = to_acpi_device(dev);
 144         struct acpi_power_meter_resource *resource = acpi_dev->driver_data;
 145         union acpi_object arg0 = { ACPI_TYPE_INTEGER };
 146         struct acpi_object_list args = { 1, &arg0 };
 147         int res;
 148         unsigned long temp;
 149         unsigned long long data;
 150         acpi_status status;
 151
 152         res = kstrtoul(buf, 10, &temp);
 153         if (res)
 154                 return res;
 155
 156         if (temp > resource->caps.max_avg_interval ||
 157             temp < resource->caps.min_avg_interval)
 158                 return -EINVAL;
 159         arg0.integer.value = temp;
 160
 161         mutex_lock(&resource->lock);
 162         status = acpi_evaluate_integer(resource->acpi_dev->handle, "_PAI",
 163                                        &args, &data);
 164         if (!ACPI_FAILURE(status))
 165                 resource->avg_interval = temp;
 166         mutex_unlock(&resource->lock);
 167
 168         if (ACPI_FAILURE(status)) {
 169                 ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PAI"));
 170                 return -EINVAL;
 171         }
 172
 173         /* _PAI returns 0 on success, nonzero otherwise */
 174         if (data)
 175                 return -EINVAL;
 176
 177         return count;
 178 }
 179
 180 /* Cap functions */
 181 static int update_cap(struct acpi_power_meter_resource *resource)
 182 {
 183         unsigned long long data;
 184         acpi_status status;
 185
 186         status = acpi_evaluate_integer(resource->acpi_dev->handle, "_GHL",
 187                                        NULL, &data);
 188         if (ACPI_FAILURE(status)) {
 189                 ACPI_EXCEPTION((AE_INFO, status, "Evaluating _GHL"));
 190                 return -ENODEV;
 191         }
 192
 193         resource->cap = data;
 194         return 0;
 195 }
 196
 197 static ssize_t show_cap(struct device *dev,
 198                         struct device_attribute *devattr,
 199                         char *buf)
 200 {
 201         struct acpi_device *acpi_dev = to_acpi_device(dev);
 202         struct acpi_power_meter_resource *resource = acpi_dev->driver_data;
 203
 204         mutex_lock(&resource->lock);
 205         update_cap(resource);
 206         mutex_unlock(&resource->lock);
 207
 208         return sprintf(buf, "%llu\n", resource->cap * 1000);
 209 }
 210
 211 static ssize_t set_cap(struct device *dev, struct device_attribute *devattr,
 212                        const char *buf, size_t count)
 213 {
 214         struct acpi_device *acpi_dev = to_acpi_device(dev);
 215         struct acpi_power_meter_resource *resource = acpi_dev->driver_data;
 216         union acpi_object arg0 = { ACPI_TYPE_INTEGER };
 217         struct acpi_object_list args = { 1, &arg0 };
 218         int res;
 219         unsigned long temp;
 220         unsigned long long data;
 221         acpi_status status;
 222
 223         res = kstrtoul(buf, 10, &temp);
 224         if (res)
 225                 return res;
 226
 227         temp = DIV_ROUND_CLOSEST(temp, 1000);
 228         if (temp > resource->caps.max_cap || temp < resource->caps.min_cap)
 229                 return -EINVAL;
 230         arg0.integer.value = temp;
 231
 232         mutex_lock(&resource->lock);
 233         status = acpi_evaluate_integer(resource->acpi_dev->handle, "_SHL",
 234                                        &args, &data);
 235         if (!ACPI_FAILURE(status))
 236                 resource->cap = temp;
 237         mutex_unlock(&resource->lock);
 238
 239         if (ACPI_FAILURE(status)) {
 240                 ACPI_EXCEPTION((AE_INFO, status, "Evaluating _SHL"));
 241                 return -EINVAL;
 242         }
 243
 244         /* _SHL returns 0 on success, nonzero otherwise */
 245         if (data)
 246                 return -EINVAL;
 247
 248         return count;
 249 }
 250
 251 /* Power meter trip points */
 252 static int set_acpi_trip(struct acpi_power_meter_resource *resource)
 253 {
 254         union acpi_object arg_objs[] = {
 255                 {ACPI_TYPE_INTEGER},
 256                 {ACPI_TYPE_INTEGER}
 257         };
 258         struct acpi_object_list args = { 2, arg_objs };
 259         unsigned long long data;
 260         acpi_status status;
 261
 262         /* Both trip levels must be set */
 263         if (resource->trip[0] < 0 || resource->trip[1] < 0)
 264                 return 0;
 265
 266         /* This driver stores min, max; ACPI wants max, min. */
 267         arg_objs[0].integer.value = resource->trip[1];
 268         arg_objs[1].integer.value = resource->trip[0];
 269
 270         status = acpi_evaluate_integer(resource->acpi_dev->handle, "_PTP",
 271                                        &args, &data);
 272         if (ACPI_FAILURE(status)) {
 273                 ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PTP"));
 274                 return -EINVAL;
 275         }
 276
 277         /* _PTP returns 0 on success, nonzero otherwise */
 278         if (data)
 279                 return -EINVAL;
 280
 281         return 0;
 282 }
 283
 284 static ssize_t set_trip(struct device *dev, struct device_attribute *devattr,
 285                         const char *buf, size_t count)
 286 {
 287         struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
 288         struct acpi_device *acpi_dev = to_acpi_device(dev);
 289         struct acpi_power_meter_resource *resource = acpi_dev->driver_data;
 290         int res;
 291         unsigned long temp;
 292
 293         res = kstrtoul(buf, 10, &temp);
 294         if (res)
 295                 return res;
 296
 297         temp = DIV_ROUND_CLOSEST(temp, 1000);
 298
 299         mutex_lock(&resource->lock);
 300         resource->trip[attr->index - 7] = temp;
 301         res = set_acpi_trip(resource);
 302         mutex_unlock(&resource->lock);
 303
 304         if (res)
 305                 return res;
 306
 307         return count;
 308 }
 309
 310 /* Power meter */
 311 static int update_meter(struct acpi_power_meter_resource *resource)
 312 {
 313         unsigned long long data;
 314         acpi_status status;
 315         unsigned long local_jiffies = jiffies;
 316
 317         if (time_before(local_jiffies, resource->sensors_last_updated +
 318                         msecs_to_jiffies(resource->caps.sampling_time)) &&
 319                         resource->sensors_valid)
 320                 return 0;
 321
 322         status = acpi_evaluate_integer(resource->acpi_dev->handle, "_PMM",
 323                                        NULL, &data);
 324         if (ACPI_FAILURE(status)) {
 325                 ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PMM"));
 326                 return -ENODEV;
 327         }
 328
 329         resource->power = data;
 330         resource->sensors_valid = 1;
 331         resource->sensors_last_updated = jiffies;
 332         return 0;
 333 }
 334
 335 static ssize_t show_power(struct device *dev,
 336                           struct device_attribute *devattr,
 337                           char *buf)
 338 {
 339         struct acpi_device *acpi_dev = to_acpi_device(dev);
 340         struct acpi_power_meter_resource *resource = acpi_dev->driver_data;
 341
 342         mutex_lock(&resource->lock);
 343         update_meter(resource);
 344         mutex_unlock(&resource->lock);
 345
 346         return sprintf(buf, "%llu\n", resource->power * 1000);
 347 }
 348
 349 /* Miscellaneous */
 350 static ssize_t show_str(struct device *dev,
 351                         struct device_attribute *devattr,
 352                         char *buf)
 353 {
 354         struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
 355         struct acpi_device *acpi_dev = to_acpi_device(dev);
 356         struct acpi_power_meter_resource *resource = acpi_dev->driver_data;
 357         acpi_string val;
 358         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);