drivers/platform/x86/dell-smbios-base.c

   1 /*
   2  *  Common functions for kernel modules using Dell SMBIOS
   3  *
   4  *  Copyright (c) Red Hat <mjg@redhat.com>
   5  *  Copyright (c) 2014 Gabriele Mazzotta <gabriele.mzt@gmail.com>
   6  *  Copyright (c) 2014 Pali Rohár <pali.rohar@gmail.com>
   7  *
   8  *  Based on documentation in the libsmbios package:
   9  *  Copyright (C) 2005-2014 Dell Inc.
  10  *
  11  *  This program is free software; you can redistribute it and/or modify
  12  *  it under the terms of the GNU General Public License version 2 as
  13  *  published by the Free Software Foundation.
  14  */
  15 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  16
  17 #include <linux/kernel.h>
  18 #include <linux/module.h>
  19 #include <linux/capability.h>
  20 #include <linux/dmi.h>
  21 #include <linux/err.h>
  22 #include <linux/mutex.h>
  23 #include <linux/platform_device.h>
  24 #include <linux/slab.h>
  25 #include "dell-smbios.h"
  26
  27 static u32 da_supported_commands;
  28 static int da_num_tokens;
  29 static struct platform_device *platform_device;
  30 static struct calling_interface_token *da_tokens;
  31 static struct device_attribute *token_location_attrs;
  32 static struct device_attribute *token_value_attrs;
  33 static struct attribute **token_attrs;
  34 static DEFINE_MUTEX(smbios_mutex);
  35
  36 struct smbios_device {
  37         struct list_head list;
  38         struct device *device;
  39         int (*call_fn)(struct calling_interface_buffer *arg);
  40 };
  41
  42 struct smbios_call {
  43         u32 need_capability;
  44         int cmd_class;
  45         int cmd_select;
  46 };
  47
  48 /* calls that are whitelisted for given capabilities */
  49 static struct smbios_call call_whitelist[] = {
  50         /* generally tokens are allowed, but may be further filtered or
  51          * restricted by token blacklist or whitelist
  52          */
  53         {CAP_SYS_ADMIN, CLASS_TOKEN_READ,       SELECT_TOKEN_STD},
  54         {CAP_SYS_ADMIN, CLASS_TOKEN_READ,       SELECT_TOKEN_AC},
  55         {CAP_SYS_ADMIN, CLASS_TOKEN_READ,       SELECT_TOKEN_BAT},
  56         {CAP_SYS_ADMIN, CLASS_TOKEN_WRITE,      SELECT_TOKEN_STD},
  57         {CAP_SYS_ADMIN, CLASS_TOKEN_WRITE,      SELECT_TOKEN_AC},
  58         {CAP_SYS_ADMIN, CLASS_TOKEN_WRITE,      SELECT_TOKEN_BAT},
  59         /* used by userspace: fwupdate */
  60         {CAP_SYS_ADMIN, CLASS_ADMIN_PROP,       SELECT_ADMIN_PROP},
  61         /* used by userspace: fwupd */
  62         {CAP_SYS_ADMIN, CLASS_INFO,             SELECT_DOCK},
  63         {CAP_SYS_ADMIN, CLASS_FLASH_INTERFACE,  SELECT_FLASH_INTERFACE},
  64 };
  65
  66 /* calls that are explicitly blacklisted */
  67 static struct smbios_call call_blacklist[] = {
  68         {0x0000,  1,  7}, /* manufacturing use */
  69         {0x0000,  6,  5}, /* manufacturing use */
  70         {0x0000, 11,  3}, /* write once */
  71         {0x0000, 11,  7}, /* write once */
  72         {0x0000, 11, 11}, /* write once */
  73         {0x0000, 19, -1}, /* diagnostics */
  74         /* handled by kernel: dell-laptop */
  75         {0x0000, CLASS_INFO, SELECT_RFKILL},
  76         {0x0000, CLASS_KBD_BACKLIGHT, SELECT_KBD_BACKLIGHT},
  77 };
  78
  79 struct token_range {
  80         u32 need_capability;
  81         u16 min;
  82         u16 max;
  83 };
  84
  85 /* tokens that are whitelisted for given capabilities */
  86 static struct token_range token_whitelist[] = {
  87         /* used by userspace: fwupdate */
  88         {CAP_SYS_ADMIN, CAPSULE_EN_TOKEN,       CAPSULE_DIS_TOKEN},
  89         /* can indicate to userspace that WMI is needed */
  90         {0x0000,        WSMT_EN_TOKEN,          WSMT_DIS_TOKEN}
  91 };
  92
  93 /* tokens that are explicitly blacklisted */
  94 static struct token_range token_blacklist[] = {
  95         {0x0000, 0x0058, 0x0059}, /* ME use */
  96         {0x0000, 0x00CD, 0x00D0}, /* raid shadow copy */
  97         {0x0000, 0x013A, 0x01FF}, /* sata shadow copy */
  98         {0x0000, 0x0175, 0x0176}, /* write once */
  99         {0x0000, 0x0195, 0x0197}, /* diagnostics */
 100         {0x0000, 0x01DC, 0x01DD}, /* manufacturing use */
 101         {0x0000, 0x027D, 0x0284}, /* diagnostics */
 102         {0x0000, 0x02E3, 0x02E3}, /* manufacturing use */
 103         {0x0000, 0x02FF, 0x02FF}, /* manufacturing use */
 104         {0x0000, 0x0300, 0x0302}, /* manufacturing use */
 105         {0x0000, 0x0325, 0x0326}, /* manufacturing use */
 106         {0x0000, 0x0332, 0x0335}, /* fan control */
 107         {0x0000, 0x0350, 0x0350}, /* manufacturing use */
 108         {0x0000, 0x0363, 0x0363}, /* manufacturing use */
 109         {0x0000, 0x0368, 0x0368}, /* manufacturing use */
 110         {0x0000, 0x03F6, 0x03F7}, /* manufacturing use */
 111         {0x0000, 0x049E, 0x049F}, /* manufacturing use */
 112         {0x0000, 0x04A0, 0x04A3}, /* disagnostics */
 113         {0x0000, 0x04E6, 0x04E7}, /* manufacturing use */
 114         {0x0000, 0x4000, 0x7FFF}, /* internal BIOS use */
 115         {0x0000, 0x9000, 0x9001}, /* internal BIOS use */
 116         {0x0000, 0xA000, 0xBFFF}, /* write only */
 117         {0x0000, 0xEFF0, 0xEFFF}, /* internal BIOS use */
 118         /* handled by kernel: dell-laptop */
 119         {0x0000, BRIGHTNESS_TOKEN,      BRIGHTNESS_TOKEN},
 120         {0x0000, KBD_LED_OFF_TOKEN,     KBD_LED_AUTO_TOKEN},
 121         {0x0000, KBD_LED_AC_TOKEN,      KBD_LED_AC_TOKEN},
 122         {0x0000, KBD_LED_AUTO_25_TOKEN, KBD_LED_AUTO_75_TOKEN},
 123         {0x0000, KBD_LED_AUTO_100_TOKEN,        KBD_LED_AUTO_100_TOKEN},
 124         {0x0000, GLOBAL_MIC_MUTE_ENABLE,        GLOBAL_MIC_MUTE_DISABLE},
 125 };
 126
 127 static LIST_HEAD(smbios_device_list);
 128
 129 int dell_smbios_error(int value)
 130 {
 131         switch (value) {
 132         case 0: /* Completed successfully */
 133                 return 0;
 134         case -1: /* Completed with error */
 135                 return -EIO;
 136         case -2: /* Function not supported */
 137                 return -ENXIO;
 138         default: /* Unknown error */
 139                 return -EINVAL;
 140         }
 141 }
 142 EXPORT_SYMBOL_GPL(dell_smbios_error);
 143
 144 int dell_smbios_register_device(struct device *d, void *call_fn)
 145 {
 146         struct smbios_device *priv;
 147
 148         priv = devm_kzalloc(d, sizeof(struct smbios_device), GFP_KERNEL);
 149         if (!priv)
 150                 return -ENOMEM;
 151         get_device(d);
 152         priv->device = d;
 153         priv->call_fn = call_fn;
 154         mutex_lock(&smbios_mutex);
 155         list_add_tail(&priv->list, &smbios_device_list);
 156         mutex_unlock(&smbios_mutex);
 157         dev_dbg(d, "Added device: %s\n", d->driver->name);
 158         return 0;
 159 }
 160 EXPORT_SYMBOL_GPL(dell_smbios_register_device);
 161
 162 void dell_smbios_unregister_device(struct device *d)
 163 {
 164         struct smbios_device *priv;
 165
 166         mutex_lock(&smbios_mutex);
 167         list_for_each_entry(priv, &smbios_device_list, list) {
 168                 if (priv->device == d) {
 169                         list_del(&priv->list);
 170                         put_device(d);
 171                         break;
 172                 }
 173         }
 174         mutex_unlock(&smbios_mutex);
 175         dev_dbg(d, "Remove device: %s\n", d->driver->name);
 176 }
 177 EXPORT_SYMBOL_GPL(dell_smbios_unregister_device);
 178
 179 int dell_smbios_call_filter(struct device *d,
 180                             struct calling_interface_buffer *buffer)
 181 {
 182         u16 t = 0;
 183         int i;
 184
 185         /* can't make calls over 30 */
 186         if (buffer->cmd_class > 30) {
 187                 dev_dbg(d, "class too big: %u\n", buffer->cmd_class);
 188                 return -EINVAL;
 189         }
 190
 191         /* supported calls on the particular system */
 192         if (!(da_supported_commands & (1 << buffer->cmd_class))) {
 193                 dev_dbg(d, "invalid command, supported commands: 0x%8x\n",
 194                         da_supported_commands);
 195                 return -EINVAL;
 196         }
 197
 198         /* match against call blacklist  */
 199         for (i = 0; i < ARRAY_SIZE(call_blacklist); i++) {
 200                 if (buffer->cmd_class != call_blacklist[i].cmd_class)
 201                         continue;
 202                 if (buffer->cmd_select != call_blacklist[i].cmd_select &&
 203                     call_blacklist[i].cmd_select != -1)
 204                         continue;
 205                 dev_dbg(d, "blacklisted command: %u/%u\n",
 206                         buffer->cmd_class, buffer->cmd_select);
 207                 return -EINVAL;
 208         }
 209
 210         /* if a token call, find token ID */
 211
 212         if ((buffer->cmd_class == CLASS_TOKEN_READ ||
 213              buffer->cmd_class == CLASS_TOKEN_WRITE) &&
 214              buffer->cmd_select < 3) {
 215                 /* tokens enabled ? */
 216                 if (!da_tokens) {
 217                         dev_dbg(d, "no token support on this system\n");
 218                         return -EINVAL;
 219                 }
 220
 221                 /* find the matching token ID */
 222                 for (i = 0; i < da_num_tokens; i++) {
 223                         if (da_tokens[i].location != buffer->input[0])
 224                                 continue;
 225                         t = da_tokens[i].tokenID;
 226                         break;
 227                 }
 228
 229                 /* token call; but token didn't exist */
 230                 if (!t) {
 231                         dev_dbg(d, "token at location %04x doesn't exist\n",
 232                                 buffer->input[0]);
 233                         return -EINVAL;
 234                 }
 235
 236                 /* match against token blacklist */
 237                 for (i = 0; i < ARRAY_SIZE(token_blacklist); i++) {
 238                         if (!token_blacklist[i].min || !token_blacklist[i].max)
 239                                 continue;
 240                         if (t >= token_blacklist[i].min &&
 241                             t <= token_blacklist[i].max)
 242                                 return -EINVAL;
 243                 }
 244
 245                 /* match against token whitelist */
 246                 for (i = 0; i < ARRAY_SIZE(token_whitelist); i++) {
 247                         if (!token_whitelist[i].min || !token_whitelist[i].max)
 248                                 continue;
 249                         if (t < token_whitelist[i].min ||
 250                             t > token_whitelist[i].max)
 251                                 continue;
 252                         if (!token_whitelist[i].need_capability ||
 253                             capable(token_whitelist[i].need_capability)) {
 254                                 dev_dbg(d, "whitelisted token: %x\n", t);
 255                                 return 0;
 256                         }
 257
 258                 }
 259         }
 260         /* match against call whitelist */
 261         for (i = 0; i < ARRAY_SIZE(call_whitelist); i++) {
 262                 if (buffer->cmd_class != call_whitelist[i].cmd_class)
 263                         continue;
 264                 if (buffer->cmd_select != call_whitelist[i].cmd_select)
 265                         continue;
 266                 if (!call_whitelist[i].need_capability ||
 267                     capable(call_whitelist[i].need_capability)) {
 268                         dev_dbg(d, "whitelisted capable command: %u/%u\n",
 269                         buffer->cmd_class, buffer->cmd_select);
 270                         return 0;
 271                 }
 272                 dev_dbg(d, "missing capability %d for %u/%u\n",
 273                         call_whitelist[i].need_capability,
 274                         buffer->cmd_class, buffer->cmd_select);
 275
 276         }
 277
 278         /* not in a whitelist, only allow processes with capabilities */
 279         if (capable(CAP_SYS_RAWIO)) {
 280                 dev_dbg(d, "Allowing %u/%u due to CAP_SYS_RAWIO\n",
 281                         buffer->cmd_class, buffer->cmd_select);
 282                 return 0;
 283         }
 284
 285         return -EACCES;
 286 }
 287 EXPORT_SYMBOL_GPL(dell_smbios_call_filter);
 288
 289 int dell_smbios_call(struct calling_interface_buffer *buffer)
 290 {
 291         int (*call_fn)(struct calling_interface_buffer *) = NULL;
 292         struct device *selected_dev = NULL;
 293         struct smbios_device *priv;
 294         int ret;
 295
 296         mutex_lock(&smbios_mutex);
 297         list_for_each_entry(priv, &smbios_device_list, list) {
 298                 if (!selected_dev || priv->device->id >= selected_dev->id) {
 299                         dev_dbg(priv->device, "Trying device ID: %d\n",
 300                                 priv->device->id);
 301                         call_fn = priv->call_fn;
 302                         selected_dev = priv->device;
 303                 }
 304         }
 305
 306         if (!selected_dev) {
 307                 ret = -ENODEV;
 308                 pr_err("No dell-smbios drivers are loaded\n");
 309                 goto out_smbios_call;
 310         }
 311
 312         ret = call_fn(buffer);
 313
 314 out_smbios_call:
 315         mutex_unlock(&smbios_mutex);
 316         return ret;
 317 }
 318 EXPORT_SYMBOL_GPL(dell_smbios_call);
 319
 320 struct calling_interface_token *dell_smbios_find_token(int tokenid)
 321 {
 322         int i;
 323
 324         if (!da_tokens)
 325                 return NULL;
 326
 327         for (i = 0; i < da_num_tokens; i++) {
 328                 if (da_tokens[i].tokenID == tokenid)
 329                         return &da_tokens[i];
 330         }
 331
 332         return NULL;
 333 }
 334 EXPORT_SYMBOL_GPL(dell_smbios_find_token);
 335
 336 static BLOCKING_NOTIFIER_HEAD(dell_laptop_chain_head);
 337
 338 int dell_laptop_register_notifier(struct notifier_block *nb)
 339 {
 340         return blocking_notifier_chain_register(&dell_laptop_chain_head, nb);
 341 }
 342 EXPORT_SYMBOL_GPL(dell_laptop_register_notifier);
 343
 344 int dell_laptop_unregister_notifier(struct notifier_block *nb)
 345 {
 346         return blocking_notifier_chain_unregister(&dell_laptop_chain_head, nb);
 347 }
 348 EXPORT_SYMBOL_GPL(dell_laptop_unregister_notifier);
 349
 350 void dell_laptop_call_notifier(unsigned long action, void *data)
 351 {
 352         blocking_notifier_call_chain(&dell_laptop_chain_head, action, data);
 353 }
 354 EXPORT_SYMBOL_GPL(dell_laptop_call_notifier);
 355
 356 static void __init parse_da_table(const struct dmi_header *dm)
 357 {
 358         /* Final token is a terminator, so we don't want to copy it */
 359         int tokens = (dm->length-11)/sizeof(struct calling_interface_token)-1;
 360         struct calling_interface_token *new_da_tokens;
 361         struct calling_interface_structure *table =
 362                 container_of(dm, struct calling_interface_structure, header);
 363
 364         /*
 365          * 4 bytes of table header, plus 7 bytes of Dell header
 366          * plus at least 6 bytes of entry
 367          */
 368
 369         if (dm->length < 17)
 370                 return;
 371
 372         da_supported_commands = table->supportedCmds;
 373
 374         new_da_tokens = krealloc(da_tokens, (da_num_tokens + tokens) *
 375                                  sizeof(struct calling_interface_token),
 376                                  GFP_KERNEL);
 377
 378         if (!new_da_tokens)
 379                 return;
 380         da_tokens = new_da_tokens;
 381
 382         memcpy(da_tokens+da_num_tokens, table->tokens,
 383                sizeof(struct calling_interface_token) * tokens);
 384
 385         da_num_tokens += tokens;
 386 }
 387
 388 static void zero_duplicates(struct device *dev)
 389 {
 390         int i, j;
 391
 392         for (i = 0; i < da_num_tokens; i++) {
 393                 if (da_tokens[i].tokenID == 0)
 394                         continue;
 395                 for (j = i+1; j < da_num_tokens; j++) {
 396                         if (da_tokens[j].tokenID == 0)
 397                                 continue;
 398                         if (da_tokens[i].tokenID == da_tokens[j].tokenID) {
 399                                 dev_dbg(dev, "Zeroing dup token ID %x(%x/%x)\n",
 400                                         da_tokens[j].tokenID,
 401                                         da_tokens[j].location,
 402                                         da_tokens[j].value);
 403                                 da_tokens[j].tokenID = 0;
 404                         }
 405                 }
 406         }
 407 }
 408
 409 static void __init find_tokens(const struct dmi_header *dm, void *dummy)
 410 {
 411         switch (dm->type) {
 412         case 0xd4: /* Indexed IO */
 413         case 0xd5: /* Protected Area Type 1 */
 414         case 0xd6: /* Protected Area Type 2 */
 415                 break;
 416         case 0xda: /* Calling interface */
 417                 parse_da_table(dm);
 418                 break;
 419         }
 420 }
 421
 422 static int match_attribute(struct device *dev,
 423                            struct device_attribute *attr)
 424 {
 425         int i;
 426
 427         for (i = 0; i < da_num_tokens * 2; i++) {
 428                 if (!token_attrs[i])
 429                         continue;
 430                 if (strcmp(token_attrs[i]->name, attr->attr.name) == 0)
 431                         return i/2;
 432         }
 433         dev_dbg(dev, "couldn't match: %s\n", attr->attr.name);
 434         return -EINVAL;
 435 }
 436
 437 static ssize_t location_show(struct device *dev,
 438                              struct device_attribute *attr, char *buf)
 439 {
 440         int i;
 441
 442         if (!capable(CAP_SYS_ADMIN))
 443                 return -EPERM;
 444
 445         i = match_attribute(dev, attr);
 446         if (i > 0)
 447                 return scnprintf(buf, PAGE_SIZE, "%08x", da_tokens[i].location);
 448         return 0;
 449 }
 450
 451 static ssize_t value_show(struct device *dev,
 452                           struct device_attribute *attr, char *buf)
 453 {
 454         int i;
 455
 456         if (!capable(CAP_SYS_ADMIN))
 457                 return -EPERM;
 458
 459         i = match_attribute(dev, attr);
 460         if (i > 0)
 461                 return scnprintf(buf, PAGE_SIZE, "%08x", da_tokens[i].value);
 462         return 0;
 463 }
 464
 465 static struct attribute_group smbios_attribute_group = {
 466         .name = "tokens"
 467 };
 468
 469 static struct platform_driver platform_driver = {
 470         .driver = {
 471                 .name = "dell-smbios",
 472         },
 473 };
 474
 475 static int build_tokens_sysfs(struct platform_device *dev)
 476 {
 477         char *location_name;
 478         char *value_name;
 479         size_t size;
 480         int ret;
 481         int i, j;
 482
 483         /* (number of tokens  + 1 for null terminated */
 484         size = sizeof(struct device_attribute) * (da_num_tokens + 1);
 485         token_location_attrs = kzalloc(size, GFP_KERNEL);
 486         if (!token_location_attrs)
 487                 return -ENOMEM;
 488         token_value_attrs = kzalloc(size, GFP_KERNEL);
 489         if (!token_value_attrs)
 490                 goto out_allocate_value;
 491
 492         /* need to store both location and value + terminator*/
 493         size = sizeof(struct attribute *) * ((2 * da_num_tokens) + 1);
 494         token_attrs = kzalloc(size, GFP_KERNEL);
 495         if (!token_attrs)
 496                 goto out_allocate_attrs;
 497
 498         for (i = 0, j = 0; i < da_num_tokens; i++) {
 499                 /* skip empty */
 500                 if (da_tokens[i].tokenID == 0)
 501                         continue;
 502                 /* add location */
 503                 location_name = kasprintf(GFP_KERNEL, "%04x_location",
 504                                           da_tokens[i].tokenID);
 505                 if (location_name == NULL)
 506                         goto out_unwind_strings;
 507                 sysfs_attr_init(&token_location_attrs[i].attr);
 508                 token_location_attrs[i].attr.name = location_name;
 509                 token_location_attrs[i].attr.mode = 0444;
 510                 token_location_attrs[i].show = location_show;
 511                 token_attrs[j++] = &token_location_attrs[i].attr;
 512
 513                 /* add value */
 514                 value_name = kasprintf(GFP_KERNEL, "%04x_value",
 515                                        da_tokens[i].tokenID);
 516                 if (value_name == NULL)
 517                         goto loop_fail_create_value;
 518                 sysfs_attr_init(&token_value_attrs[i].attr);
 519                 token_value_attrs[i].attr.name = value_name;
 520                 token_value_attrs[i].attr.mode = 0444;
 521                 token_value_attrs[i].show = value_show;
 522                 token_attrs[j++] = &token_value_attrs[i].attr;
 523                 continue;
 524
 525 loop_fail_create_value:
 526                 kfree(location_name);
 527                 goto out_unwind_strings;
 528         }
 529         smbios_attribute_group.attrs = token_attrs;
 530
 531         ret = sysfs_create_group(&dev->dev.kobj, &smbios_attribute_group);
 532         if (ret)
 533                 goto out_unwind_strings;
 534         return 0;
 535
 536 out_unwind_strings:
 537         while (i--) {
 538                 kfree(token_location_attrs[i].attr.name);
 539                 kfree(token_value_attrs[i].attr.name);
 540         }
 541         kfree(token_attrs);
 542 out_allocate_attrs:
 543         kfree(token_value_attrs);
 544 out_allocate_value:
 545         kfree(token_location_attrs);
 546
 547         return -ENOMEM;
 548 }
 549
 550 static void free_group(struct platform_device *pdev)
 551 {
 552         int i;
 553
 554         sysfs_remove_group(&pdev->dev.kobj,
 555                                 &smbios_attribute_group);
 556         for (i = 0; i < da_num_tokens; i++) {
 557                 kfree(token_location_attrs[i].attr.name);
 558                 kfree(token_value_attrs[i].attr.name);
 559         }
 560         kfree(token_attrs);
 561         kfree(token_value_attrs);
 562         kfree(token_location_attrs);
 563 }
 564
 565 static int __init dell_smbios_init(void)
 566 {
 567         int ret, wmi, smm;
 568
 569         if (!dmi_find_device(DMI_DEV_TYPE_OEM_STRING, "Dell System", NULL) &&
 570             !dmi_find_device(DMI_DEV_TYPE_OEM_STRING, "www.dell.com", NULL)) {
 571                 pr_err("Unable to run on non-Dell system\n");
 572                 return -ENODEV;
 573         }
 574
 575         dmi_walk(find_tokens, NULL);
 576
 577         ret = platform_driver_register(&platform_driver);
 578         if (ret)
 579                 goto fail_platform_driver;
 580
 581         platform_device = platform_device_alloc("dell-smbios", 0);
 582         if (!platform_device) {
 583                 ret = -ENOMEM;
 584                 goto fail_platform_device_alloc;
 585         }
 586         ret = platform_device_add(platform_device);
 587         if (ret)
 588                 goto fail_platform_device_add;
 589
 590         /* register backends */
 591         wmi = init_dell_smbios_wmi();
 592         if (wmi)
 593                 pr_debug("Failed to initialize WMI backend: %d\n", wmi);
 594         smm = init_dell_smbios_smm();
 595         if (smm)
 596                 pr_debug("Failed to initialize SMM backend: %d\n", smm);
 597         if (wmi && smm) {
 598                 pr_err("No SMBIOS backends available (wmi: %d, smm: %d)\n",
 599                         wmi, smm);
 600                 ret = -ENODEV;
 601                 goto fail_create_group;
 602         }
 603
 604         if (da_tokens)  {
 605                 /* duplicate tokens will cause problems building sysfs files */
 606                 zero_duplicates(&platform_device->dev);
 607
 608                 ret = build_tokens_sysfs(platform_device);
 609                 if (ret)
 610                         goto fail_sysfs;
 611         }
 612
 613         return 0;
 614
 615 fail_sysfs:
 616         free_group(platform_device);
 617
 618 fail_create_group:
 619         platform_device_del(platform_device);
 620
 621 fail_platform_device_add:
 622         platform_device_put(platform_device);
 623
 624 fail_platform_device_alloc:
 625         platform_driver_unregister(&platform_driver);
 626
 627 fail_platform_driver:
 628         kfree(da_tokens);
 629         return ret;
 630 }
 631
 632 static void __exit dell_smbios_exit(void)
 633 {
 634         exit_dell_smbios_wmi();
 635         exit_dell_smbios_smm();
 636         mutex_lock(&smbios_mutex);
 637         if (platform_device) {
 638                 if (da_tokens)
 639                         free_group(platform_device);
 640                 platform_device_unregister(platform_device);
 641                 platform_driver_unregister(&platform_driver);
 642         }
 643         kfree(da_tokens);
 644         mutex_unlock(&smbios_mutex);
 645 }
 646
 647 module_init(dell_smbios_init);
 648 module_exit(dell_smbios_exit);
 649
 650 MODULE_AUTHOR("Matthew Garrett <mjg@redhat.com>");
 651 MODULE_AUTHOR("Gabriele Mazzotta <gabriele.mzt@gmail.com>");
 652 MODULE_AUTHOR("Pali Rohár <pali.rohar@gmail.com>");
 653 MODULE_AUTHOR("Mario Limonciello <mario.limonciello@dell.com>");
 654 MODULE_DESCRIPTION("Common functions for kernel modules using Dell SMBIOS");
 655 MODULE_LICENSE("GPL");