drivers/misc/enclosure.c

   1 /*
   2  * Enclosure Services
   3  *
   4  * Copyright (C) 2008 James Bottomley <James.Bottomley@HansenPartnership.com>
   5  *
   6 **-----------------------------------------------------------------------------
   7 **
   8 **  This program is free software; you can redistribute it and/or
   9 **  modify it under the terms of the GNU General Public License
  10 **  version 2 as published by the Free Software Foundation.
  11 **
  12 **  This program is distributed in the hope that it will be useful,
  13 **  but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 **  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 **  GNU General Public License for more details.
  16 **
  17 **  You should have received a copy of the GNU General Public License
  18 **  along with this program; if not, write to the Free Software
  19 **  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  20 **
  21 **-----------------------------------------------------------------------------
  22 */
  23 #include <linux/device.h>
  24 #include <linux/enclosure.h>
  25 #include <linux/err.h>
  26 #include <linux/list.h>
  27 #include <linux/kernel.h>
  28 #include <linux/module.h>
  29 #include <linux/mutex.h>
  30 #include <linux/slab.h>
  31
  32 static LIST_HEAD(container_list);
  33 static DEFINE_MUTEX(container_list_lock);
  34 static struct class enclosure_class;
  35
  36 /**
  37  * enclosure_find - find an enclosure given a parent device
  38  * @dev:        the parent to match against
  39  * @start:      Optional enclosure device to start from (NULL if none)
  40  *
  41  * Looks through the list of registered enclosures to find all those
  42  * with @dev as a parent.  Returns NULL if no enclosure is
  43  * found. @start can be used as a starting point to obtain multiple
  44  * enclosures per parent (should begin with NULL and then be set to
  45  * each returned enclosure device). Obtains a reference to the
  46  * enclosure class device which must be released with device_put().
  47  * If @start is not NULL, a reference must be taken on it which is
  48  * released before returning (this allows a loop through all
  49  * enclosures to exit with only the reference on the enclosure of
  50  * interest held).  Note that the @dev may correspond to the actual
  51  * device housing the enclosure, in which case no iteration via @start
  52  * is required.
  53  */
  54 struct enclosure_device *enclosure_find(struct device *dev,
  55                                         struct enclosure_device *start)
  56 {
  57         struct enclosure_device *edev;
  58
  59         mutex_lock(&container_list_lock);
  60         edev = list_prepare_entry(start, &container_list, node);
  61         if (start)
  62                 put_device(&start->edev);
  63
  64         list_for_each_entry_continue(edev, &container_list, node) {
  65                 struct device *parent = edev->edev.parent;
  66                 /* parent might not be immediate, so iterate up to
  67                  * the root of the tree if necessary */
  68                 while (parent) {
  69                         if (parent == dev) {
  70                                 get_device(&edev->edev);
  71                                 mutex_unlock(&container_list_lock);
  72                                 return edev;
  73                         }
  74                         parent = parent->parent;
  75                 }
  76         }
  77         mutex_unlock(&container_list_lock);
  78
  79         return NULL;
  80 }
  81 EXPORT_SYMBOL_GPL(enclosure_find);
  82
  83 /**
  84  * enclosure_for_each_device - calls a function for each enclosure
  85  * @fn:         the function to call
  86  * @data:       the data to pass to each call
  87  *
  88  * Loops over all the enclosures calling the function.
  89  *
  90  * Note, this function uses a mutex which will be held across calls to
  91  * @fn, so it must have non atomic context, and @fn may (although it
  92  * should not) sleep or otherwise cause the mutex to be held for
  93  * indefinite periods
  94  */
  95 int enclosure_for_each_device(int (*fn)(struct enclosure_device *, void *),
  96                               void *data)
  97 {
  98         int error = 0;
  99         struct enclosure_device *edev;
 100
 101         mutex_lock(&container_list_lock);
 102         list_for_each_entry(edev, &container_list, node) {
 103                 error = fn(edev, data);
 104                 if (error)
 105                         break;
 106         }
 107         mutex_unlock(&container_list_lock);
 108
 109         return error;
 110 }
 111 EXPORT_SYMBOL_GPL(enclosure_for_each_device);
 112
 113 /**
 114  * enclosure_register - register device as an enclosure
 115  *
 116  * @dev:        device containing the enclosure
 117  * @components: number of components in the enclosure
 118  *
 119  * This sets up the device for being an enclosure.  Note that @dev does
 120  * not have to be a dedicated enclosure device.  It may be some other type
 121  * of device that additionally responds to enclosure services
 122  */
 123 struct enclosure_device *
 124 enclosure_register(struct device *dev, const char *name, int components,
 125                    struct enclosure_component_callbacks *cb)
 126 {
 127         struct enclosure_device *edev =
 128                 kzalloc(sizeof(struct enclosure_device) +
 129                         sizeof(struct enclosure_component)*components,
 130                         GFP_KERNEL);
 131         int err, i;
 132
 133         BUG_ON(!cb);
 134
 135         if (!edev)
 136                 return ERR_PTR(-ENOMEM);
 137
 138         edev->components = components;
 139
 140         edev->edev.class = &enclosure_class;
 141         edev->edev.parent = get_device(dev);
 142         edev->cb = cb;
 143         dev_set_name(&edev->edev, "%s", name);
 144         err = device_register(&edev->edev);
 145         if (err)
 146                 goto err;
 147
 148         for (i = 0; i < components; i++)
 149                 edev->component[i].number = -1;
 150
 151         mutex_lock(&container_list_lock);
 152         list_add_tail(&edev->node, &container_list);
 153         mutex_unlock(&container_list_lock);
 154
 155         return edev;
 156
 157  err:
 158         put_device(edev->edev.parent);
 159         kfree(edev);
 160         return ERR_PTR(err);
 161 }
 162 EXPORT_SYMBOL_GPL(enclosure_register);
 163
 164 static struct enclosure_component_callbacks enclosure_null_callbacks;
 165
 166 /**
 167  * enclosure_unregister - remove an enclosure
 168  *
 169  * @edev:       the registered enclosure to remove;
 170  */
 171 void enclosure_unregister(struct enclosure_device *edev)
 172 {
 173         int i;
 174
 175         mutex_lock(&container_list_lock);
 176         list_del(&edev->node);
 177         mutex_unlock(&container_list_lock);
 178
 179         for (i = 0; i < edev->components; i++)
 180                 if (edev->component[i].number != -1)
 181                         device_unregister(&edev->component[i].cdev);
 182
 183         /* prevent any callbacks into service user */
 184         edev->cb = &enclosure_null_callbacks;
 185         device_unregister(&edev->edev);
 186 }
 187 EXPORT_SYMBOL_GPL(enclosure_unregister);
 188
 189 #define ENCLOSURE_NAME_SIZE     64
 190
 191 static void enclosure_link_name(struct enclosure_component *cdev, char *name)
 192 {
 193         strcpy(name, "enclosure_device:");
 194         strcat(name, dev_name(&cdev->cdev));
 195 }
 196
 197 static void enclosure_remove_links(struct enclosure_component *cdev)
 198 {
 199         char name[ENCLOSURE_NAME_SIZE];
 200
 201         /*
 202          * In odd circumstances, like multipath devices, something else may
 203          * already have removed the links, so check for this condition first.
 204          */
 205         if (!cdev->dev->kobj.sd)
 206                 return;
 207
 208         enclosure_link_name(cdev, name);
 209         sysfs_remove_link(&cdev->dev->kobj, name);
 210         sysfs_remove_link(&cdev->cdev.kobj, "device");
 211 }
 212
 213 static int enclosure_add_links(struct enclosure_component *cdev)
 214 {
 215         int error;
 216         char name[ENCLOSURE_NAME_SIZE];
 217
 218         error = sysfs_create_link(&cdev->cdev.kobj, &cdev->dev->kobj, "device");
 219         if (error)
 220                 return error;
 221
 222         enclosure_link_name(cdev, name);
 223         error = sysfs_create_link(&cdev->dev->kobj, &cdev->cdev.kobj, name);
 224         if (error)
 225                 sysfs_remove_link(&cdev->cdev.kobj, "device");
 226
 227         return error;
 228 }
 229
 230 static void enclosure_release(struct device *cdev)
 231 {
 232         struct enclosure_device *edev = to_enclosure_device(cdev);
 233
 234         put_device(cdev->parent);
 235         kfree(edev);
 236 }
 237
 238 static void enclosure_component_release(struct device *dev)
 239 {
 240         struct enclosure_component *cdev = to_enclosure_component(dev);
 241
 242         if (cdev->dev) {
 243                 enclosure_remove_links(cdev);
 244                 put_device(cdev->dev);
 245         }
 246         put_device(dev->parent);
 247 }
 248
 249 static const struct attribute_group *enclosure_groups[];
 250
 251 /**
 252  * enclosure_component_register - add a particular component to an enclosure
 253  * @edev:       the enclosure to add the component
 254  * @num:        the device number
 255  * @type:       the type of component being added
 256  * @name:       an optional name to appear in sysfs (leave NULL if none)
 257  *
 258  * Registers the component.  The name is optional for enclosures that
 259  * give their components a unique name.  If not, leave the field NULL
 260  * and a name will be assigned.
 261  *
 262  * Returns a pointer to the enclosure component or an error.
 263  */
 264 struct enclosure_component *
 265 enclosure_component_register(struct enclosure_device *edev,
 266                              unsigned int number,
 267                              enum enclosure_component_type type,
 268                              const char *name)
 269 {
 270         struct enclosure_component *ecomp;
 271         struct device *cdev;
 272         int err;
 273
 274         if (number >= edev->components)
 275                 return ERR_PTR(-EINVAL);
 276
 277         ecomp = &edev->component[number];
 278
 279         if (ecomp->number != -1)
 280                 return ERR_PTR(-EINVAL);
 281
 282         ecomp->type = type;
 283         ecomp->number = number;
 284         cdev = &ecomp->cdev;
 285         cdev->parent = get_device(&edev->edev);
 286         if (name && name[0])
 287                 dev_set_name(cdev, "%s", name);
 288         else
 289                 dev_set_name(cdev, "%u", number);
 290
 291         cdev->release = enclosure_component_release;
 292         cdev->groups = enclosure_groups;
 293
 294         err = device_register(cdev);
 295         if (err) {
 296                 ecomp->number = -1;
 297                 put_device(cdev);
 298                 return ERR_PTR(err);
 299         }
 300
 301         return ecomp;
 302 }
 303 EXPORT_SYMBOL_GPL(enclosure_component_register);
 304
 305 /**
 306  * enclosure_add_device - add a device as being part of an enclosure
 307  * @edev:       the enclosure device being added to.
 308  * @num:        the number of the component
 309  * @dev:        the device being added
 310  *
 311  * Declares a real device to reside in slot (or identifier) @num of an
 312  * enclosure.  This will cause the relevant sysfs links to appear.
 313  * This function may also be used to change a device associated with
 314  * an enclosure without having to call enclosure_remove_device() in
 315  * between.
 316  *
 317  * Returns zero on success or an error.
 318  */
 319 int enclosure_add_device(struct enclosure_device *edev, int component,
 320                          struct device *dev)
 321 {
 322         struct enclosure_component *cdev;
 323
 324         if (!edev || component >= edev->components)
 325                 return -EINVAL;
 326
 327         cdev = &edev->component[component];
 328
 329         if (cdev->dev == dev)
 330                 return -EEXIST;
 331
 332         if (cdev->dev)
 333                 enclosure_remove_links(cdev);
 334
 335         put_device(cdev->dev);
 336         cdev->dev = get_device(dev);
 337         return enclosure_add_links(cdev);
 338 }
 339 EXPORT_SYMBOL_GPL(enclosure_add_device);
 340
 341 /**
 342  * enclosure_remove_device - remove a device from an enclosure
 343  * @edev:       the enclosure device
 344  * @num:        the number of the component to remove
 345  *
 346  * Returns zero on success or an error.
 347  *
 348  */
 349 int enclosure_remove_device(struct enclosure_device *edev, struct device *dev)
 350 {
 351         struct enclosure_component *cdev;
 352         int i;
 353
 354         if (!edev || !dev)
 355                 return -EINVAL;
 356
 357         for (i = 0; i < edev->components; i++) {
 358                 cdev = &edev->component[i];
 359                 if (cdev->dev == dev) {
 360                         enclosure_remove_links(cdev);
 361                         device_del(&cdev->cdev);
 362                         put_device(dev);
 363                         cdev->dev = NULL;
 364                         return device_add(&cdev->cdev);
 365                 }
 366         }
 367         return -ENODEV;
 368 }
 369 EXPORT_SYMBOL_GPL(enclosure_remove_device);
 370
 371 /*
 372  * sysfs pieces below
 373  */
 374
 375 static ssize_t enclosure_show_components(struct device *cdev,
 376                                          struct device_attribute *attr,
 377                                          char *buf)
 378 {
 379         struct enclosure_device *edev = to_enclosure_device(cdev);
 380
 381         return snprintf(buf, 40, "%d\n", edev->components);
 382 }
 383
 384 static struct device_attribute enclosure_attrs[] = {
 385         __ATTR(components, S_IRUGO, enclosure_show_components, NULL),
 386         __ATTR_NULL
 387 };
 388
 389 static struct class enclosure_class = {
 390         .name                   = "enclosure",
 391         .owner                  = THIS_MODULE,
 392         .dev_release            = enclosure_release,
 393         .dev_attrs              = enclosure_attrs,
 394 };
 395
 396 static const char *const enclosure_status [] = {
 397         [ENCLOSURE_STATUS_UNSUPPORTED] = "unsupported",
 398         [ENCLOSURE_STATUS_OK] = "OK",
 399         [ENCLOSURE_STATUS_CRITICAL] = "critical",
 400         [ENCLOSURE_STATUS_NON_CRITICAL] = "non-critical",
 401         [ENCLOSURE_STATUS_UNRECOVERABLE] = "unrecoverable",
 402         [ENCLOSURE_STATUS_NOT_INSTALLED] = "not installed",
 403         [ENCLOSURE_STATUS_UNKNOWN] = "unknown",
 404         [ENCLOSURE_STATUS_UNAVAILABLE] = "unavailable",
 405         [ENCLOSURE_STATUS_MAX] = NULL,
 406 };
 407
 408 static const char *const enclosure_type [] = {
 409         [ENCLOSURE_COMPONENT_DEVICE] = "device",
 410         [ENCLOSURE_COMPONENT_ARRAY_DEVICE] = "array device",
 411 };
 412
 413 static ssize_t get_component_fault(struct device *cdev,
 414                                    struct device_attribute *attr, char *buf)
 415 {
 416         struct enclosure_device *edev = to_enclosure_device(cdev->parent);
 417         struct enclosure_component *ecomp = to_enclosure_component(cdev);
 418
 419         if (edev->cb->get_fault)
 420                 edev->cb->get_fault(edev, ecomp);
 421         return snprintf(buf, 40, "%d\n", ecomp->fault);
 422 }
 423
 424 static ssize_t set_component_fault(struct device *cdev,
 425                                    struct device_attribute *attr,
 426                                    const char *buf, size_t count)
 427 {
 428         struct enclosure_device *edev = to_enclosure_device(cdev->parent);
 429         struct enclosure_component *ecomp = to_enclosure_component(cdev);
 430         int val = simple_strtoul(buf, NULL, 0);
 431
 432         if (edev->cb->set_fault)
 433                 edev->cb->set_fault(edev, ecomp, val);
 434         return count;
 435 }
 436
 437 static ssize_t get_component_status(struct device *cdev,
 438                                     struct device_attribute *attr,char *buf)
 439 {
 440         struct enclosure_device *edev = to_enclosure_device(cdev->parent);
 441         struct enclosure_component *ecomp = to_enclosure_component(cdev);
 442
 443         if (edev->cb->get_status)
 444                 edev->cb->get_status(edev, ecomp);
 445         return snprintf(buf, 40, "%s\n", enclosure_status[ecomp->status]);
 446 }
 447
 448 static ssize_t set_component_status(struct device *cdev,
 449                                     struct device_attribute *attr,
 450                                     const char *buf, size_t count)
 451 {
 452         struct enclosure_device *edev = to_enclosure_device(cdev->parent);
 453         struct enclosure_component *ecomp = to_enclosure_component(cdev);
 454         int i;
 455
 456         for (i = 0; enclosure_status[i]; i++) {
 457                 if (strncmp(buf, enclosure_status[i],
 458                             strlen(enclosure_status[i])) == 0 &&
 459                     (buf[strlen(enclosure_status[i])] == '\n' ||
 460                      buf[strlen(enclosure_status[i])] == '\0'))
 461                         break;
 462         }
 463
 464         if (enclosure_status[i] && edev->cb->set_status) {
 465                 edev->cb->set_status(edev, ecomp, i);
 466                 return count;
 467         } else
 468                 return -EINVAL;
 469 }
 470
 471 static ssize_t get_component_active(struct device *cdev,
 472                                     struct device_attribute *attr, char *buf)
 473 {
 474         struct enclosure_device *edev = to_enclosure_device(cdev->parent);
 475         struct enclosure_component *ecomp = to_enclosure_component(cdev);
 476
 477         if (edev->cb->get_active)
 478                 edev->cb->get_active(edev, ecomp);
 479         return snprintf(buf, 40, "%d\n", ecomp->active);
 480 }
 481
 482 static ssize_t set_component_active(struct device *cdev,
 483                                     struct device_attribute *attr,
 484                                     const char *buf, size_t count)
 485 {
 486         struct enclosure_device *edev = to_enclosure_device(cdev->parent);
 487         struct enclosure_component *ecomp = to_enclosure_component(cdev);
 488         int val = simple_strtoul(buf, NULL, 0);
 489
 490         if (edev->cb->set_active)
 491                 edev->cb->set_active(edev, ecomp, val);
 492         return count;
 493 }
 494
 495 static ssize_t get_component_locate(struct device *cdev,
 496                                     struct device_attribute *attr, char *buf)
 497 {
 498         struct enclosure_device *edev = to_enclosure_device(cdev->parent);
 499         struct enclosure_component *ecomp = to_enclosure_component(cdev);
 500
 501         if (edev->cb->get_locate)
 502                 edev->cb->get_locate(edev, ecomp);
 503         return snprintf(buf, 40, "%d\n", ecomp->locate);
 504 }
 505
 506 static ssize_t set_component_locate(struct device *cdev,
 507                                     struct device_attribute *attr,
 508                                     const char *buf, size_t count)
 509 {
 510         struct enclosure_device *edev = to_enclosure_device(cdev->parent);
 511         struct enclosure_component *ecomp = to_enclosure_component(cdev);
 512         int val = simple_strtoul(buf, NULL, 0);
 513
 514         if (edev->cb->set_locate)
 515                 edev->cb->set_locate(edev, ecomp, val);
 516         return count;
 517 }
 518
 519 static ssize_t get_component_type(struct device *cdev,
 520                                   struct device_attribute *attr, char *buf)
 521 {
 522         struct enclosure_component *ecomp = to_enclosure_component(cdev);
 523
 524         return snprintf(buf, 40, "%s\n", enclosure_type[ecomp->type]);
 525 }
 526
 527
 528 static DEVICE_ATTR(fault, S_IRUGO | S_IWUSR, get_component_fault,
 529                     set_component_fault);
 530 static DEVICE_ATTR(status, S_IRUGO | S_IWUSR, get_component_status,
 531                    set_component_status);
 532 static DEVICE_ATTR(active, S_IRUGO | S_IWUSR, get_component_active,
 533                    set_component_active);
 534 static DEVICE_ATTR(locate, S_IRUGO | S_IWUSR, get_component_locate,
 535                    set_component_locate);
 536 static DEVICE_ATTR(type, S_IRUGO, get_component_type, NULL);
 537
 538 static struct attribute *enclosure_component_attrs[] = {
 539         &dev_attr_fault.attr,
 540         &dev_attr_status.attr,
 541         &dev_attr_active.attr,
 542         &dev_attr_locate.attr,
 543         &dev_attr_type.attr,
 544         NULL
 545 };
 546
 547 static struct attribute_group enclosure_group = {
 548         .attrs = enclosure_component_attrs,
 549 };
 550
 551 static const struct attribute_group *enclosure_groups[] = {
 552         &enclosure_group,
 553         NULL
 554 };
 555
 556 static int __init enclosure_init(void)
 557 {
 558         int err;
 559
 560         err = class_register(&enclosure_class);
 561         if (err)
 562                 return err;
 563
 564         return 0;
 565 }
 566
 567 static void __exit enclosure_exit(void)
 568 {
 569         class_unregister(&enclosure_class);
 570 }
 571
 572 module_init(enclosure_init);
 573 module_exit(enclosure_exit);
 574
 575 MODULE_AUTHOR("James Bottomley");
 576 MODULE_DESCRIPTION("Enclosure Services");
 577 MODULE_LICENSE("GPL v2");