linux/drivers/hwmon/acpi_power_meter.c
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   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
  35#define METER_NOTIFY_CONFIG     0x80
  36#define METER_NOTIFY_TRIP       0x81
  37#define METER_NOTIFY_CAP        0x82
  38#define METER_NOTIFY_CAPPING    0x83
  39#define METER_NOTIFY_INTERVAL   0x84
  40
  41#define POWER_AVERAGE_NAME      "power1_average"
  42#define POWER_CAP_NAME          "power1_cap"
  43#define POWER_AVG_INTERVAL_NAME "power1_average_interval"
  44#define POWER_ALARM_NAME        "power1_alarm"
  45
  46static int cap_in_hardware;
  47static bool force_cap_on;
  48
  49static int can_cap_in_hardware(void)
  50{
  51        return force_cap_on || cap_in_hardware;
  52}
  53
  54static const struct acpi_device_id power_meter_ids[] = {
  55        {"ACPI000D", 0},
  56        {"", 0},
  57};
  58MODULE_DEVICE_TABLE(acpi, power_meter_ids);
  59
  60struct acpi_power_meter_capabilities {
  61        u64             flags;
  62        u64             units;
  63        u64             type;
  64        u64             accuracy;
  65        u64             sampling_time;
  66        u64             min_avg_interval;
  67        u64             max_avg_interval;
  68        u64             hysteresis;
  69        u64             configurable_cap;
  70        u64             min_cap;
  71        u64             max_cap;
  72};
  73
  74struct acpi_power_meter_resource {
  75        struct acpi_device      *acpi_dev;
  76        acpi_bus_id             name;
  77        struct mutex            lock;
  78        struct device           *hwmon_dev;
  79        struct acpi_power_meter_capabilities    caps;
  80        acpi_string             model_number;
  81        acpi_string             serial_number;
  82        acpi_string             oem_info;
  83        u64             power;
  84        u64             cap;
  85        u64             avg_interval;
  86        int                     sensors_valid;
  87        unsigned long           sensors_last_updated;
  88        struct sensor_device_attribute  sensors[NUM_SENSORS];
  89        int                     num_sensors;
  90        s64                     trip[2];
  91        int                     num_domain_devices;
  92        struct acpi_device      **domain_devices;
  93        struct kobject          *holders_dir;
  94};
  95
  96struct sensor_template {
  97        char *label;
  98        ssize_t (*show)(struct device *dev,
  99                        struct device_attribute *devattr,
 100                        char *buf);
 101        ssize_t (*set)(struct device *dev,
 102                       struct device_attribute *devattr,
 103                       const char *buf, size_t count);
 104        int index;
 105};
 106
 107/* Averaging interval */
 108static int update_avg_interval(struct acpi_power_meter_resource *resource)
 109{
 110        unsigned long long data;
 111        acpi_status status;
 112
 113        status = acpi_evaluate_integer(resource->acpi_dev->handle, "_GAI",
 114                                       NULL, &data);
 115        if (ACPI_FAILURE(status)) {
 116                acpi_evaluation_failure_warn(resource->acpi_dev->handle, "_GAI",
 117                                             status);
 118                return -ENODEV;
 119        }
 120
 121        resource->avg_interval = data;
 122        return 0;
 123}
 124
 125static 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
 139static ssize_t set_avg_interval(struct device *dev,
 140                                struct device_attribute *devattr,
 141                                const char *buf, size_t count)
 142{
 143        struct acpi_device *acpi_dev = to_acpi_device(dev);
 144        struct acpi_power_meter_resource *resource = acpi_dev->driver_data;
 145        union acpi_object arg0 = { ACPI_TYPE_INTEGER };
 146        struct acpi_object_list args = { 1, &arg0 };
 147        int res;
 148        unsigned long temp;
 149        unsigned long long data;
 150        acpi_status status;
 151
 152        res = kstrtoul(buf, 10, &temp);
 153        if (res)
 154                return res;
 155
 156        if (temp > resource->caps.max_avg_interval ||
 157            temp < resource->caps.min_avg_interval)
 158                return -EINVAL;
 159        arg0.integer.value = temp;
 160
 161        mutex_lock(&resource->lock);
 162        status = acpi_evaluate_integer(resource->acpi_dev->handle, "_PAI",
 163                                       &args, &data);
 164        if (ACPI_SUCCESS(status))
 165                resource->avg_interval = temp;
 166        mutex_unlock(&resource->lock);
 167
 168        if (ACPI_FAILURE(status)) {
 169                acpi_evaluation_failure_warn(resource->acpi_dev->handle, "_PAI",
 170                                             status);
 171                return -EINVAL;
 172        }
 173
 174        /* _PAI returns 0 on success, nonzero otherwise */
 175        if (data)
 176                return -EINVAL;
 177
 178        return count;
 179}
 180
 181/* Cap functions */
 182static int update_cap(struct acpi_power_meter_resource *resource)
 183{
 184        unsigned long long data;
 185        acpi_status status;
 186
 187        status = acpi_evaluate_integer(resource->acpi_dev->handle, "_GHL",
 188                                       NULL, &data);
 189        if (ACPI_FAILURE(status)) {
 190                acpi_evaluation_failure_warn(resource->acpi_dev->handle, "_GHL",
 191                                             status);
 192                return -ENODEV;
 193        }
 194
 195        resource->cap = data;
 196        return 0;
 197}
 198
 199static ssize_t show_cap(struct device *dev,
 200                        struct device_attribute *devattr,
 201                        char *buf)
 202{
 203        struct acpi_device *acpi_dev = to_acpi_device(dev);
 204        struct acpi_power_meter_resource *resource = acpi_dev->driver_data;
 205
 206        mutex_lock(&resource->lock);
 207        update_cap(resource);
 208        mutex_unlock(&resource->lock);
 209
 210        return sprintf(buf, "%llu\n", resource->cap * 1000);
 211}
 212
 213static ssize_t set_cap(struct device *dev, struct device_attribute *devattr,
 214                       const char *buf, size_t count)
 215{
 216        struct acpi_device *acpi_dev = to_acpi_device(dev);
 217        struct acpi_power_meter_resource *resource = acpi_dev->driver_data;
 218        union acpi_object arg0 = { ACPI_TYPE_INTEGER };
 219        struct acpi_object_list args = { 1, &arg0 };
 220        int res;
 221        unsigned long temp;
 222        unsigned long long data;
 223        acpi_status status;
 224
 225        res = kstrtoul(buf, 10, &temp);
 226        if (res)
 227                return res;
 228
 229        temp = DIV_ROUND_CLOSEST(temp, 1000);
 230        if (temp > resource->caps.max_cap || temp < resource->caps.min_cap)
 231                return -EINVAL;
 232        arg0.integer.value = temp;
 233
 234        mutex_lock(&resource->lock);
 235        status = acpi_evaluate_integer(resource->acpi_dev->handle, "_SHL",
 236                                       &args, &data);
 237        if (ACPI_SUCCESS(status))
 238                resource->cap = temp;
 239        mutex_unlock(&resource->lock);
 240
 241        if (ACPI_FAILURE(status)) {
 242                acpi_evaluation_failure_warn(resource->acpi_dev->handle, "_SHL",
 243                                             status);
 244                return -EINVAL;
 245        }
 246
 247        /* _SHL returns 0 on success, nonzero otherwise */
 248        if (data)
 249                return -EINVAL;
 250
 251        return count;
 252}
 253
 254/* Power meter trip points */
 255static int set_acpi_trip(struct acpi_power_meter_resource *resource)
 256{
 257        union acpi_object arg_objs[] = {
 258                {ACPI_TYPE_INTEGER},
 259                {ACPI_TYPE_INTEGER}
 260        };
 261        struct acpi_object_list args = { 2, arg_objs };
 262        unsigned long long data;
 263        acpi_status status;
 264
 265        /* Both trip levels must be set */
 266        if (resource->trip[0] < 0 || resource->trip[1] < 0)
 267                return 0;
 268
 269        /* This driver stores min, max; ACPI wants max, min. */
 270        arg_objs[0].integer.value = resource->trip[1];
 271        arg_objs[1].integer.value = resource->trip[0];
 272
 273        status = acpi_evaluate_integer(resource->acpi_dev->handle, "_PTP",
 274                                       &args, &data);
 275        if (ACPI_FAILURE(status)) {
 276                acpi_evaluation_failure_warn(resource->acpi_dev->handle, "_PTP",
 277                                             status);
 278                return -EINVAL;
 279        }
 280
 281        /* _PTP returns 0 on success, nonzero otherwise */
 282        if (data)
 283                return -EINVAL;
 284
 285        return 0;
 286}
 287
 288static ssize_t set_trip(struct device *dev, struct device_attribute *devattr,
 289                        const char *buf, size_t count)
 290{
 291        struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
 292        struct acpi_device *acpi_dev = to_acpi_device(dev);
 293        struct acpi_power_meter_resource *resource = acpi_dev->driver_data;
 294        int res;
 295        unsigned long temp;
 296
 297        res = kstrtoul(buf, 10, &temp);
 298        if (res)
 299                return res;
 300
 301        temp = DIV_ROUND_CLOSEST(temp, 1000);
 302
 303        mutex_lock(&resource->lock);
 304        resource->trip[attr->index - 7] = temp;
 305        res = set_acpi_trip(resource);
 306        mutex_unlock(&resource->lock);
 307
 308        if (res)
 309                return res;
 310
 311        return count;
 312}
 313
 314/* Power meter */
 315static int update_meter(struct acpi_power_meter_resource *resource)
 316{
 317        unsigned long long data;
 318        acpi_status status;
 319        unsigned long local_jiffies = jiffies;
 320
 321        if (time_before(local_jiffies, resource->sensors_last_updated +
 322                        msecs_to_jiffies(resource->caps.sampling_time)) &&
 323                        resource->sensors_valid)
 324                return 0;
 325
 326        status = acpi_evaluate_integer(resource->acpi_dev->handle, "_PMM",
 327                                       NULL, &data);
 328        if (ACPI_FAILURE(status)) {
 329                acpi_evaluation_failure_warn(resource->acpi_dev->handle, "_PMM",
 330                                             status);
 331                return -ENODEV;
 332        }
 333
 334        resource->power = data;
 335        resource->sensors_valid = 1;
 336        resource->sensors_last_updated = jiffies;
 337        return 0;
 338}
 339
 340static ssize_t show_power(struct device *dev,
 341                          struct device_attribute *devattr,
 342                          char *buf)
 343{
 344        struct acpi_device *acpi_dev = to_acpi_device(dev);
 345        struct acpi_power_meter_resource *resource = acpi_dev->driver_data;
 346
 347        mutex_lock(&resource->lock);
 348        update_meter(resource);
 349        mutex_unlock(&resource->lock);
 350
 351        return sprintf(buf, "%llu\n", resource->power * 1000);
 352}
 353
 354/* Miscellaneous */
 355static ssize_t show_str(struct device *dev,
 356                        struct device_attribute *devattr,
 357                        char *buf)
 358{
 359        struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
 360        struct acpi_device *acpi_dev = to_acpi_device(dev);
 361        struct acpi_power_meter_resource *resource = acpi_dev->driver_data;
 362        acpi_string val;
 363        int ret;
 364
 365        mutex_lock(&resource->lock);
 366        switch (attr->index) {
 367        case 0:
 368                val = resource->model_number;
 369                break;
 370        case 1:
 371                val = resource->serial_number;
 372                break;
 373        case 2:
 374                val = resource->oem_info;
 375                break;
 376        default:
 377                WARN(1, "Implementation error: unexpected attribute index %d\n",
 378                     attr->index);
 379                val = "";
 380                break;
 381        }
 382        ret = sprintf(buf, "%s\n", val);
 383        mutex_unlock(&resource->lock);
 384        return ret;
 385}
 386
 387static ssize_t show_val(struct device *dev,
 388                        struct device_attribute *devattr,
 389                        char *buf)
 390{
 391        struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
 392        struct acpi_device *acpi_dev = to_acpi_device(dev);
 393        struct acpi_power_meter_resource *resource = acpi_dev->driver_data;
 394        u64 val = 0;
 395
 396        switch (attr->index) {
 397        case 0:
 398                val = resource->caps.min_avg_interval;
 399                break;
 400        case 1:
 401                val = resource->caps.max_avg_interval;
 402                break;
 403        case 2:
 404                val = resource->caps.min_cap * 1000;
 405                break;
 406        case 3:
 407                val = resource->caps.max_cap * 1000;
 408                break;
 409        case 4:
 410                if (resource->caps.hysteresis == UNKNOWN_HYSTERESIS)
 411                        return sprintf(buf, "unknown\n");
 412
 413                val = resource->caps.hysteresis * 1000;
 414                break;
 415        case 5:
 416                if (resource->caps.flags & POWER_METER_IS_BATTERY)
 417                        val = 1;
 418                else
 419                        val = 0;
 420                break;
 421        case 6:
 422                if (resource->power > resource->cap)
 423                        val = 1;
 424                else
 425                        val = 0;
 426                break;
 427        case 7:
 428        case 8:
 429                if (resource->trip[attr->index - 7] < 0)
 430                        return sprintf(buf, "unknown\n");
 431
 432                val = resource->trip[attr->index - 7] * 1000;
 433                break;
 434        default:
 435                WARN(1, "Implementation error: unexpected attribute index %d\n",
 436                     attr->index);
 437                break;
 438        }
 439
 440        return sprintf(buf, "%llu\n", val);
 441}
 442
 443static ssize_t show_accuracy(struct device *dev,
 444                             struct device_attribute *devattr,
 445                             char *buf)
 446{
 447        struct acpi_device *acpi_dev = to_acpi_device(dev);
 448        struct acpi_power_meter_resource *resource = acpi_dev->driver_data;
 449        unsigned int acc = resource->caps.accuracy;
 450
 451        return sprintf(buf, "%u.%u%%\n", acc / 1000, acc % 1000);
 452}
 453
 454static ssize_t show_name(struct device *dev,
 455                         struct device_attribute *devattr,
 456                         char *buf)
 457{
 458        return sprintf(buf, "%s\n", ACPI_POWER_METER_NAME);
 459}
 460
 461#define RO_SENSOR_TEMPLATE(_label, _show, _index)       \
 462        {                                               \
 463                .label = _label,                        \
 464                .show  = _show,                         \
 465                .index = _index,                        \
 466        }
 467
 468#define RW_SENSOR_TEMPLATE(_label, _show, _set, _index) \
 469        {                                               \
 470                .label = _label,                        \
 471                .show  = _show,                         \
 472                .set   = _set,                          \
 473                .index = _index,                        \
 474        }
 475
 476/* Sensor descriptions.  If you add a sensor, update NUM_SENSORS above! */
 477static struct sensor_template meter_attrs[] = {
 478        RO_SENSOR_TEMPLATE(POWER_AVERAGE_NAME, show_power, 0),
 479        RO_SENSOR_TEMPLATE("power1_accuracy", show_accuracy, 0),
 480        RO_SENSOR_TEMPLATE("power1_average_interval_min", show_val, 0),
 481        RO_SENSOR_TEMPLATE("power1_average_interval_max", show_val, 1),
 482        RO_SENSOR_TEMPLATE("power1_is_battery", show_val, 5),
 483        RW_SENSOR_TEMPLATE(POWER_AVG_INTERVAL_NAME, show_avg_interval,
 484                set_avg_interval, 0),
 485        {},
 486};
 487
 488static struct sensor_template misc_cap_attrs[] = {
 489        RO_SENSOR_TEMPLATE("power1_cap_min", show_val, 2),
 490        RO_SENSOR_TEMPLATE("power1_cap_max", show_val, 3),
 491        RO_SENSOR_TEMPLATE("power1_cap_hyst", show_val, 4),
 492        RO_SENSOR_TEMPLATE(POWER_ALARM_NAME, show_val, 6),
 493        {},
 494};
 495
 496static struct sensor_template ro_cap_attrs[] = {
 497        RO_SENSOR_TEMPLATE(POWER_CAP_NAME, show_cap, 0),
 498        {},
 499};
 500
 501static struct sensor_template rw_cap_attrs[] = {
 502        RW_SENSOR_TEMPLATE(POWER_CAP_NAME, show_cap, set_cap, 0),
 503        {},
 504};
 505
 506static struct sensor_template trip_attrs[] = {
 507        RW_SENSOR_TEMPLATE("power1_average_min", show_val, set_trip, 7),
 508        RW_SENSOR_TEMPLATE("power1_average_max", show_val, set_trip, 8),
 509        {},
 510};
 511
 512static struct sensor_template misc_attrs[] = {
 513        RO_SENSOR_TEMPLATE("name", show_name, 0),
 514        RO_SENSOR_TEMPLATE("power1_model_number", show_str, 0),
 515        RO_SENSOR_TEMPLATE("power1_oem_info", show_str, 2),
 516        RO_SENSOR_TEMPLATE("power1_serial_number", show_str, 1),
 517        {},
 518};
 519
 520#undef RO_SENSOR_TEMPLATE
 521#undef RW_SENSOR_TEMPLATE
 522
 523/* Read power domain data */
 524static void remove_domain_devices(struct acpi_power_meter_resource *resource)
 525{
 526        int i;
 527
 528        if (!resource->num_domain_devices)
 529                return;
 530
 531        for (i = 0; i < resource->num_domain_devices; i++) {
 532                struct acpi_device *obj = resource->domain_devices[i];
 533                if (!obj)
 534                        continue;
 535
 536                sysfs_remove_link(resource->holders_dir,
 537                                  kobject_name(&obj->dev.kobj));
 538                put_device(&obj->dev);
 539        }
 540
 541        kfree(resource->domain_devices);
 542        kobject_put(resource->holders_dir);
 543        resource->num_domain_devices = 0;
 544}
 545
 546static int read_domain_devices(struct acpi_power_meter_resource *resource)
 547{
 548        int res = 0;
 549        int i;
 550        struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 551        union acpi_object *pss;
 552        acpi_status status;
 553
 554        status = acpi_evaluate_object(resource->acpi_dev->handle, "_PMD", NULL,
 555                                      &buffer);
 556        if (ACPI_FAILURE(status)) {
 557                acpi_evaluation_failure_warn(resource->acpi_dev->handle, "_PMD",
 558                                             status);
 559                return -ENODEV;
 560        }
 561
 562        pss = buffer.pointer;
 563        if (!pss ||
 564            pss->type != ACPI_TYPE_PACKAGE) {
 565                dev_err(&resource->acpi_dev->dev, ACPI_POWER_METER_NAME
 566                        "Invalid _PMD data\n");
 567                res = -EFAULT;
 568                goto end;
 569        }
 570
 571        if (!pss->package.count)
 572                goto end;
 573
 574        resource->domain_devices = kcalloc(pss->package.count,
 575                                           sizeof(struct acpi_device *),
 576                                           GFP_KERNEL);
 577        if (!resource->domain_devices) {
 578                res = -ENOMEM;
 579                goto end;
 580        }
 581
 582        resource->holders_dir = kobject_create_and_add("measures",
 583                                        &resource->acpi_dev->dev.kobj);
 584        if (!resource->holders_dir) {
 585                res = -ENOMEM;
 586                goto exit_free;
 587        }
 588
 589        resource->num_domain_devices = pss->package.count;
 590
 591        for (i = 0; i < pss->package.count; i++) {
 592                struct acpi_device *obj;
 593                union acpi_object *element = &(pss->package.elements[i]);
 594
 595                /* Refuse non-references */
 596                if (element->type != ACPI_TYPE_LOCAL_REFERENCE)
 597                        continue;
 598
 599                /* Create a symlink to domain objects */
 600                resource->domain_devices[i] = NULL;
 601                if (acpi_bus_get_device(element->reference.handle,
 602                                        &resource->domain_devices[i]))
 603                        continue;
 604
 605                obj = resource->domain_devices[i];
 606                get_device(&obj->dev);
 607
 608                res = sysfs_create_link(resource->holders_dir, &obj->dev.kobj,
 609                                      kobject_name(&obj->dev.kobj));
 610                if (res) {
 611                        put_device(&obj->dev);
 612                        resource->domain_devices[i] = NULL;
 613                }
 614        }
 615
 616        res = 0;
 617        goto end;
 618
 619exit_free:
 620        kfree(resource->domain_devices);
 621end:
 622        kfree(buffer.pointer);
 623        return res;
 624}
 625
 626/* Registration and deregistration */
 627static int register_attrs(struct acpi_power_meter_resource *resource,
 628                          struct sensor_template *attrs)
 629{
 630        struct device *dev = &resource->acpi_dev->dev;
 631        struct sensor_device_attribute *sensors =
 632                &resource->sensors[resource->num_sensors];
 633        int res = 0;
 634
 635        while (attrs->label) {
 636                sensors->dev_attr.attr.name = attrs->label;
 637                sensors->dev_attr.attr.mode = 0444;
 638                sensors->dev_attr.show = attrs->show;
 639                sensors->index = attrs->index;
 640
 641                if (attrs->set) {
 642                        sensors->dev_attr.attr.mode |= 0200;
 643                        sensors->dev_attr.store = attrs->set;
 644                }
 645
 646                sysfs_attr_init(&sensors->dev_attr.attr);
 647                res = device_create_file(dev, &sensors->dev_attr);
 648                if (res) {
 649                        sensors->dev_attr.attr.name = NULL;
 650                        goto error;
 651                }
 652                sensors++;
 653                resource->num_sensors++;
 654                attrs++;
 655        }
 656
 657error:
 658        return res;
 659}
 660
 661static void remove_attrs(struct acpi_power_meter_resource *resource)
 662{
 663        int i;
 664
 665        for (i = 0; i < resource->num_sensors; i++) {
 666                if (!resource->sensors[i].dev_attr.attr.name)
 667                        continue;
 668                device_remove_file(&resource->acpi_dev->dev,
 669                                   &resource->sensors[i].dev_attr);
 670        }
 671
 672        remove_domain_devices(resource);
 673
 674        resource->num_sensors = 0;
 675}
 676
 677static int setup_attrs(struct acpi_power_meter_resource *resource)
 678{
 679        int res = 0;
 680
 681        res = read_domain_devices(resource);
 682        if (res)
 683                return res;
 684
 685        if (resource->caps.flags & POWER_METER_CAN_MEASURE) {
 686                res = register_attrs(resource, meter_attrs);
 687                if (res)
 688                        goto error;
 689        }
 690
 691        if (resource->caps.flags & POWER_METER_CAN_CAP) {
 692                if (!can_cap_in_hardware()) {
 693                        dev_warn(&resource->acpi_dev->dev,
 694                                 "Ignoring unsafe software power cap!\n");
 695                        goto skip_unsafe_cap;
 696                }
 697
 698                if (resource->caps.configurable_cap)
 699                        res = register_attrs(resource, rw_cap_attrs);
 700                else
 701                        res = register_attrs(resource, ro_cap_attrs);
 702
 703                if (res)
 704                        goto error;
 705
 706                res = register_attrs(resource, misc_cap_attrs);
 707                if (res)
 708                        goto error;
 709        }
 710
 711skip_unsafe_cap:
 712        if (resource->caps.flags & POWER_METER_CAN_TRIP) {
 713                res = register_attrs(resource, trip_attrs);
 714                if (res)
 715                        goto error;
 716        }
 717
 718        res = register_attrs(resource, misc_attrs);
 719        if (res)
 720                goto error;
 721
 722        return res;
 723error:
 724        remove_attrs(resource);
 725        return res;
 726}
 727
 728static void free_capabilities(struct acpi_power_meter_resource *resource)
 729{
 730        acpi_string *str;
 731        int i;
 732
 733        str = &resource->model_number;
 734        for (i = 0; i < 3; i++, str++) {
 735                kfree(*str);
 736                *str = NULL;
 737        }
 738}
 739
 740static int read_capabilities(struct acpi_power_meter_resource *resource)
 741{
 742        int res = 0;
 743        int i;
 744        struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 745        struct acpi_buffer state = { 0, NULL };
 746        struct acpi_buffer format = { sizeof("NNNNNNNNNNN"), "NNNNNNNNNNN" };
 747        union acpi_object *pss;
 748        acpi_string *str;
 749        acpi_status status;
 750
 751        status = acpi_evaluate_object(resource->acpi_dev->handle, "_PMC", NULL,
 752                                      &buffer);
 753        if (ACPI_FAILURE(status)) {
 754                acpi_evaluation_failure_warn(resource->acpi_dev->handle, "_PMC",
 755                                             status);
 756                return -ENODEV;
 757        }
 758
 759        pss = buffer.pointer;
 760        if (!pss ||
 761            pss->type != ACPI_TYPE_PACKAGE ||
 762            pss->package.count != 14) {
 763                dev_err(&resource->acpi_dev->dev, ACPI_POWER_METER_NAME
 764                        "Invalid _PMC data\n");
 765                res = -EFAULT;
 766                goto end;
 767        }
 768
 769        /* Grab all the integer data at once */
 770        state.length = sizeof(struct acpi_power_meter_capabilities);
 771        state.pointer = &resource->caps;
 772
 773        status = acpi_extract_package(pss, &format, &state);
 774        if (ACPI_FAILURE(status)) {
 775                dev_err(&resource->acpi_dev->dev, ACPI_POWER_METER_NAME
 776                        "_PMC package parsing failed: %s\n",
 777                        acpi_format_exception(status));
 778                res = -EFAULT;
 779                goto end;
 780        }
 781
 782        if (resource->caps.units) {
 783                dev_err(&resource->acpi_dev->dev, ACPI_POWER_METER_NAME
 784                        "Unknown units %llu.\n",
 785                        resource->caps.units);
 786                res = -EINVAL;
 787                goto end;
 788        }
 789
 790        /* Grab the string data */
 791        str = &resource->model_number;
 792
 793        for (i = 11; i < 14; i++) {
 794                union acpi_object *element = &(pss->package.elements[i]);
 795
 796                if (element->type != ACPI_TYPE_STRING) {
 797                        res = -EINVAL;
 798                        goto error;
 799                }
 800
 801                *str = kcalloc(element->string.length + 1, sizeof(u8),
 802                               GFP_KERNEL);
 803                if (!*str) {
 804                        res = -ENOMEM;
 805                        goto error;
 806                }
 807
 808                strncpy(*str, element->string.pointer, element->string.length);
 809                str++;
 810        }
 811
 812        dev_info(&resource->acpi_dev->dev, "Found ACPI power meter.\n");
 813        goto end;
 814error:
 815        free_capabilities(resource);
 816end:
 817        kfree(buffer.pointer);
 818        return res;
 819}
 820
 821/* Handle ACPI event notifications */
 822static void acpi_power_meter_notify(struct acpi_device *device, u32 event)
 823{
 824        struct acpi_power_meter_resource *resource;
 825        int res;
 826
 827        if (!device || !acpi_driver_data(device))
 828                return;
 829
 830        resource = acpi_driver_data(device);
 831
 832        switch (event) {
 833        case METER_NOTIFY_CONFIG:
 834                mutex_lock(&resource->lock);
 835                free_capabilities(resource);
 836                res = read_capabilities(resource);
 837                mutex_unlock(&resource->lock);
 838                if (res)
 839                        break;
 840
 841                remove_attrs(resource);
 842                setup_attrs(resource);
 843                break;
 844        case METER_NOTIFY_TRIP:
 845                sysfs_notify(&device->dev.kobj, NULL, POWER_AVERAGE_NAME);
 846                break;
 847        case METER_NOTIFY_CAP:
 848                sysfs_notify(&device->dev.kobj, NULL, POWER_CAP_NAME);
 849                break;
 850        case METER_NOTIFY_INTERVAL:
 851                sysfs_notify(&device->dev.kobj, NULL, POWER_AVG_INTERVAL_NAME);
 852                break;
 853        case METER_NOTIFY_CAPPING:
 854                sysfs_notify(&device->dev.kobj, NULL, POWER_ALARM_NAME);
 855                dev_info(&device->dev, "Capping in progress.\n");
 856                break;
 857        default:
 858                WARN(1, "Unexpected event %d\n", event);
 859                break;
 860        }
 861
 862        acpi_bus_generate_netlink_event(ACPI_POWER_METER_CLASS,
 863                                        dev_name(&device->dev), event, 0);
 864}
 865
 866static int acpi_power_meter_add(struct acpi_device *device)
 867{
 868        int res;
 869        struct acpi_power_meter_resource *resource;
 870
 871        if (!device)
 872                return -EINVAL;
 873
 874        resource = kzalloc(sizeof(struct acpi_power_meter_resource),
 875                           GFP_KERNEL);
 876        if (!resource)
 877                return -ENOMEM;
 878
 879        resource->sensors_valid = 0;
 880        resource->acpi_dev = device;
 881        mutex_init(&resource->lock);
 882        strcpy(acpi_device_name(device), ACPI_POWER_METER_DEVICE_NAME);
 883        strcpy(acpi_device_class(device), ACPI_POWER_METER_CLASS);
 884        device->driver_data = resource;
 885
 886        res = read_capabilities(resource);
 887        if (res)
 888                goto exit_free;
 889
 890        resource->trip[0] = resource->trip[1] = -1;
 891
 892        res = setup_attrs(resource);
 893        if (res)
 894                goto exit_free_capability;
 895
 896        resource->hwmon_dev = hwmon_device_register(&device->dev);
 897        if (IS_ERR(resource->hwmon_dev)) {
 898                res = PTR_ERR(resource->hwmon_dev);
 899                goto exit_remove;
 900        }
 901
 902        res = 0;
 903        goto exit;
 904
 905exit_remove:
 906        remove_attrs(resource);
 907exit_free_capability:
 908        free_capabilities(resource);
 909exit_free:
 910        kfree(resource);
 911exit:
 912        return res;
 913}
 914
 915static int acpi_power_meter_remove(struct acpi_device *device)
 916{
 917        struct acpi_power_meter_resource *resource;
 918
 919        if (!device || !acpi_driver_data(device))
 920                return -EINVAL;
 921
 922        resource = acpi_driver_data(device);
 923        hwmon_device_unregister(resource->hwmon_dev);
 924
 925        remove_attrs(resource);
 926        free_capabilities(resource);
 927
 928        kfree(resource);
 929        return 0;
 930}
 931
 932#ifdef CONFIG_PM_SLEEP
 933
 934static int acpi_power_meter_resume(struct device *dev)
 935{
 936        struct acpi_power_meter_resource *resource;
 937
 938        if (!dev)
 939                return -EINVAL;
 940
 941        resource = acpi_driver_data(to_acpi_device(dev));
 942        if (!resource)
 943                return -EINVAL;
 944
 945        free_capabilities(resource);
 946        read_capabilities(resource);
 947
 948        return 0;
 949}
 950
 951#endif /* CONFIG_PM_SLEEP */
 952
 953static SIMPLE_DEV_PM_OPS(acpi_power_meter_pm, NULL, acpi_power_meter_resume);
 954
 955static struct acpi_driver acpi_power_meter_driver = {
 956        .name = "power_meter",
 957        .class = ACPI_POWER_METER_CLASS,
 958        .ids = power_meter_ids,
 959        .ops = {
 960                .add = acpi_power_meter_add,
 961                .remove = acpi_power_meter_remove,
 962                .notify = acpi_power_meter_notify,
 963                },
 964        .drv.pm = &acpi_power_meter_pm,
 965};
 966
 967/* Module init/exit routines */
 968static int __init enable_cap_knobs(const struct dmi_system_id *d)
 969{
 970        cap_in_hardware = 1;
 971        return 0;
 972}
 973
 974static const struct dmi_system_id pm_dmi_table[] __initconst = {
 975        {
 976                enable_cap_knobs, "IBM Active Energy Manager",
 977                {
 978                        DMI_MATCH(DMI_SYS_VENDOR, "IBM")
 979                },
 980        },
 981        {}
 982};
 983
 984static int __init acpi_power_meter_init(void)
 985{
 986        int result;
 987
 988        if (acpi_disabled)
 989                return -ENODEV;
 990
 991        dmi_check_system(pm_dmi_table);
 992
 993        result = acpi_bus_register_driver(&acpi_power_meter_driver);
 994        if (result < 0)
 995                return result;
 996
 997        return 0;
 998}
 999
1000static void __exit acpi_power_meter_exit(void)
1001{
1002        acpi_bus_unregister_driver(&acpi_power_meter_driver);
1003}
1004
1005MODULE_AUTHOR("Darrick J. Wong <darrick.wong@oracle.com>");
1006MODULE_DESCRIPTION("ACPI 4.0 power meter driver");
1007MODULE_LICENSE("GPL");
1008
1009module_param(force_cap_on, bool, 0644);
1010MODULE_PARM_DESC(force_cap_on, "Enable power cap even it is unsafe to do so.");
1011
1012module_init(acpi_power_meter_init);
1013module_exit(acpi_power_meter_exit);
1014