drivers/base/class.c

   1 /*
   2  * class.c - basic device class management
   3  *
   4  * Copyright (c) 2002-3 Patrick Mochel
   5  * Copyright (c) 2002-3 Open Source Development Labs
   6  * Copyright (c) 2003-2004 Greg Kroah-Hartman
   7  * Copyright (c) 2003-2004 IBM Corp.
   8  *
   9  * This file is released under the GPLv2
  10  *
  11  */
  12
  13 #include <linux/config.h>
  14 #include <linux/device.h>
  15 #include <linux/module.h>
  16 #include <linux/init.h>
  17 #include <linux/string.h>
  18 #include "base.h"
  19
  20 #define to_class_attr(_attr) container_of(_attr, struct class_attribute, attr)
  21 #define to_class(obj) container_of(obj, struct class, subsys.kset.kobj)
  22
  23 static ssize_t
  24 class_attr_show(struct kobject * kobj, struct attribute * attr, char * buf)
  25 {
  26         struct class_attribute * class_attr = to_class_attr(attr);
  27         struct class * dc = to_class(kobj);
  28         ssize_t ret = 0;
  29
  30         if (class_attr->show)
  31                 ret = class_attr->show(dc, buf);
  32         return ret;
  33 }
  34
  35 static ssize_t
  36 class_attr_store(struct kobject * kobj, struct attribute * attr,
  37                  const char * buf, size_t count)
  38 {
  39         struct class_attribute * class_attr = to_class_attr(attr);
  40         struct class * dc = to_class(kobj);
  41         ssize_t ret = 0;
  42
  43         if (class_attr->store)
  44                 ret = class_attr->store(dc, buf, count);
  45         return ret;
  46 }
  47
  48 static void class_release(struct kobject * kobj)
  49 {
  50         struct class *class = to_class(kobj);
  51
  52         pr_debug("class '%s': release.\n", class->name);
  53
  54         if (class->class_release)
  55                 class->class_release(class);
  56         else
  57                 pr_debug("class '%s' does not have a release() function, "
  58                          "be careful\n", class->name);
  59 }
  60
  61 static struct sysfs_ops class_sysfs_ops = {
  62         .show   = class_attr_show,
  63         .store  = class_attr_store,
  64 };
  65
  66 static struct kobj_type ktype_class = {
  67         .sysfs_ops      = &class_sysfs_ops,
  68         .release        = class_release,
  69 };
  70
  71 /* Hotplug events for classes go to the class_obj subsys */
  72 static decl_subsys(class, &ktype_class, NULL);
  73
  74
  75 int class_create_file(struct class * cls, const struct class_attribute * attr)
  76 {
  77         int error;
  78         if (cls) {
  79                 error = sysfs_create_file(&cls->subsys.kset.kobj, &attr->attr);
  80         } else
  81                 error = -EINVAL;
  82         return error;
  83 }
  84
  85 void class_remove_file(struct class * cls, const struct class_attribute * attr)
  86 {
  87         if (cls)
  88                 sysfs_remove_file(&cls->subsys.kset.kobj, &attr->attr);
  89 }
  90
  91 struct class * class_get(struct class * cls)
  92 {
  93         if (cls)
  94                 return container_of(subsys_get(&cls->subsys), struct class, subsys);
  95         return NULL;
  96 }
  97
  98 void class_put(struct class * cls)
  99 {
 100         subsys_put(&cls->subsys);
 101 }
 102
 103
 104 static int add_class_attrs(struct class * cls)
 105 {
 106         int i;
 107         int error = 0;
 108
 109         if (cls->class_attrs) {
 110                 for (i = 0; attr_name(cls->class_attrs[i]); i++) {
 111                         error = class_create_file(cls,&cls->class_attrs[i]);
 112                         if (error)
 113                                 goto Err;
 114                 }
 115         }
 116  Done:
 117         return error;
 118  Err:
 119         while (--i >= 0)
 120                 class_remove_file(cls,&cls->class_attrs[i]);
 121         goto Done;
 122 }
 123
 124 static void remove_class_attrs(struct class * cls)
 125 {
 126         int i;
 127
 128         if (cls->class_attrs) {
 129                 for (i = 0; attr_name(cls->class_attrs[i]); i++)
 130                         class_remove_file(cls,&cls->class_attrs[i]);
 131         }
 132 }
 133
 134 int class_register(struct class * cls)
 135 {
 136         int error;
 137
 138         pr_debug("device class '%s': registering\n", cls->name);
 139
 140         INIT_LIST_HEAD(&cls->children);
 141         INIT_LIST_HEAD(&cls->interfaces);
 142         error = kobject_set_name(&cls->subsys.kset.kobj, "%s", cls->name);
 143         if (error)
 144                 return error;
 145
 146         subsys_set_kset(cls, class_subsys);
 147
 148         error = subsystem_register(&cls->subsys);
 149         if (!error) {
 150                 error = add_class_attrs(class_get(cls));
 151                 class_put(cls);
 152         }
 153         return error;
 154 }
 155
 156 void class_unregister(struct class * cls)
 157 {
 158         pr_debug("device class '%s': unregistering\n", cls->name);
 159         remove_class_attrs(cls);
 160         subsystem_unregister(&cls->subsys);
 161 }
 162
 163
 164 /* Class Device Stuff */
 165
 166 int class_device_create_file(struct class_device * class_dev,
 167                              const struct class_device_attribute * attr)
 168 {
 169         int error = -EINVAL;
 170         if (class_dev)
 171                 error = sysfs_create_file(&class_dev->kobj, &attr->attr);
 172         return error;
 173 }
 174
 175 void class_device_remove_file(struct class_device * class_dev,
 176                               const struct class_device_attribute * attr)
 177 {
 178         if (class_dev)
 179                 sysfs_remove_file(&class_dev->kobj, &attr->attr);
 180 }
 181
 182 int class_device_create_bin_file(struct class_device *class_dev,
 183                                  struct bin_attribute *attr)
 184 {
 185         int error = -EINVAL;
 186         if (class_dev)
 187                 error = sysfs_create_bin_file(&class_dev->kobj, attr);
 188         return error;
 189 }
 190
 191 void class_device_remove_bin_file(struct class_device *class_dev,
 192                                   struct bin_attribute *attr)
 193 {
 194         if (class_dev)
 195                 sysfs_remove_bin_file(&class_dev->kobj, attr);
 196 }
 197
 198 static int class_device_dev_link(struct class_device * class_dev)
 199 {
 200         if (class_dev->dev)
 201                 return sysfs_create_link(&class_dev->kobj,
 202                                          &class_dev->dev->kobj, "device");
 203         return 0;
 204 }
 205
 206 static void class_device_dev_unlink(struct class_device * class_dev)
 207 {
 208         sysfs_remove_link(&class_dev->kobj, "device");
 209 }
 210
 211 static int class_device_driver_link(struct class_device * class_dev)
 212 {
 213         if ((class_dev->dev) && (class_dev->dev->driver))
 214                 return sysfs_create_link(&class_dev->kobj,
 215                                          &class_dev->dev->driver->kobj, "driver");
 216         return 0;
 217 }
 218
 219 static void class_device_driver_unlink(struct class_device * class_dev)
 220 {
 221         sysfs_remove_link(&class_dev->kobj, "driver");
 222 }
 223
 224
 225 static ssize_t
 226 class_device_attr_show(struct kobject * kobj, struct attribute * attr,
 227                        char * buf)
 228 {
 229         struct class_device_attribute * class_dev_attr = to_class_dev_attr(attr);
 230         struct class_device * cd = to_class_dev(kobj);
 231         ssize_t ret = 0;
 232
 233         if (class_dev_attr->show)
 234                 ret = class_dev_attr->show(cd, buf);
 235         return ret;
 236 }
 237
 238 static ssize_t
 239 class_device_attr_store(struct kobject * kobj, struct attribute * attr,
 240                         const char * buf, size_t count)
 241 {
 242         struct class_device_attribute * class_dev_attr = to_class_dev_attr(attr);
 243         struct class_device * cd = to_class_dev(kobj);
 244         ssize_t ret = 0;
 245
 246         if (class_dev_attr->store)
 247                 ret = class_dev_attr->store(cd, buf, count);
 248         return ret;
 249 }
 250
 251 static struct sysfs_ops class_dev_sysfs_ops = {
 252         .show   = class_device_attr_show,
 253         .store  = class_device_attr_store,
 254 };
 255
 256 static void class_dev_release(struct kobject * kobj)
 257 {
 258         struct class_device *cd = to_class_dev(kobj);
 259         struct class * cls = cd->class;
 260
 261         pr_debug("device class '%s': release.\n", cd->class_id);
 262
 263         if (cls->release)
 264                 cls->release(cd);
 265         else {
 266                 printk(KERN_ERR "Device class '%s' does not have a release() function, "
 267                         "it is broken and must be fixed.\n",
 268                         cd->class_id);
 269                 WARN_ON(1);
 270         }
 271 }
 272
 273 static struct kobj_type ktype_class_device = {
 274         .sysfs_ops      = &class_dev_sysfs_ops,
 275         .release        = class_dev_release,
 276 };
 277
 278 static int class_hotplug_filter(struct kset *kset, struct kobject *kobj)
 279 {
 280         struct kobj_type *ktype = get_ktype(kobj);
 281
 282         if (ktype == &ktype_class_device) {
 283                 struct class_device *class_dev = to_class_dev(kobj);
 284                 if (class_dev->class)
 285                         return 1;
 286         }
 287         return 0;
 288 }
 289
 290 static char *class_hotplug_name(struct kset *kset, struct kobject *kobj)
 291 {
 292         struct class_device *class_dev = to_class_dev(kobj);
 293
 294         return class_dev->class->name;
 295 }
 296
 297 static int class_hotplug(struct kset *kset, struct kobject *kobj, char **envp,
 298                          int num_envp, char *buffer, int buffer_size)
 299 {
 300         struct class_device *class_dev = to_class_dev(kobj);
 301         int retval = 0;
 302         int i = 0;
 303         int length = 0;
 304
 305         pr_debug("%s - name = %s\n", __FUNCTION__, class_dev->class_id);
 306
 307         if (class_dev->dev) {
 308                 /* add physical device, backing this device  */
 309                 struct device *dev = class_dev->dev;
 310                 char *path = kobject_get_path(&dev->kobj, GFP_KERNEL);
 311
 312                 add_hotplug_env_var(envp, num_envp, &i, buffer, buffer_size,
 313                                     &length, "PHYSDEVPATH=%s", path);
 314                 kfree(path);
 315
 316                 /* add bus name of physical device */
 317                 if (dev->bus)
 318                         add_hotplug_env_var(envp, num_envp, &i,
 319                                             buffer, buffer_size, &length,
 320                                             "PHYSDEVBUS=%s", dev->bus->name);
 321
 322                 /* add driver name of physical device */
 323                 if (dev->driver)
 324                         add_hotplug_env_var(envp, num_envp, &i,
 325                                             buffer, buffer_size, &length,
 326                                             "PHYSDEVDRIVER=%s", dev->driver->name);
 327
 328                 /* terminate, set to next free slot, shrink available space */
 329                 envp[i] = NULL;
 330                 envp = &envp[i];
 331                 num_envp -= i;
 332                 buffer = &buffer[length];
 333                 buffer_size -= length;
 334         }
 335
 336         if (class_dev->class->hotplug) {
 337                 /* have the bus specific function add its stuff */
 338                 retval = class_dev->class->hotplug (class_dev, envp, num_envp,
 339                                                     buffer, buffer_size);
 340                         if (retval) {
 341                         pr_debug ("%s - hotplug() returned %d\n",
 342                                   __FUNCTION__, retval);
 343                 }
 344         }
 345
 346         return retval;
 347 }
 348
 349 static struct kset_hotplug_ops class_hotplug_ops = {
 350         .filter =       class_hotplug_filter,
 351         .name =         class_hotplug_name,
 352         .hotplug =      class_hotplug,
 353 };
 354
 355 static decl_subsys(class_obj, &ktype_class_device, &class_hotplug_ops);
 356
 357
 358 static int class_device_add_attrs(struct class_device * cd)
 359 {
 360         int i;
 361         int error = 0;
 362         struct class * cls = cd->class;
 363
 364         if (cls->class_dev_attrs) {
 365                 for (i = 0; attr_name(cls->class_dev_attrs[i]); i++) {
 366                         error = class_device_create_file(cd,
 367                                                          &cls->class_dev_attrs[i]);
 368                         if (error)
 369                                 goto Err;
 370                 }
 371         }
 372  Done:
 373         return error;
 374  Err:
 375         while (--i >= 0)
 376                 class_device_remove_file(cd,&cls->class_dev_attrs[i]);
 377         goto Done;
 378 }
 379
 380 static void class_device_remove_attrs(struct class_device * cd)
 381 {
 382         int i;
 383         struct class * cls = cd->class;
 384
 385         if (cls->class_dev_attrs) {
 386                 for (i = 0; attr_name(cls->class_dev_attrs[i]); i++)
 387                         class_device_remove_file(cd,&cls->class_dev_attrs[i]);
 388         }
 389 }
 390
 391 void class_device_initialize(struct class_device *class_dev)
 392 {
 393         kobj_set_kset_s(class_dev, class_obj_subsys);
 394         kobject_init(&class_dev->kobj);
 395         INIT_LIST_HEAD(&class_dev->node);
 396 }
 397
 398 int class_device_add(struct class_device *class_dev)
 399 {
 400         struct class * parent = NULL;
 401         struct class_interface * class_intf;
 402         int error;
 403
 404         class_dev = class_device_get(class_dev);
 405         if (!class_dev)
 406                 return -EINVAL;
 407
 408         if (!strlen(class_dev->class_id)) {
 409                 error = -EINVAL;
 410                 goto register_done;
 411         }
 412
 413         parent = class_get(class_dev->class);
 414
 415         pr_debug("CLASS: registering class device: ID = '%s'\n",
 416                  class_dev->class_id);
 417
 418         /* first, register with generic layer. */
 419         kobject_set_name(&class_dev->kobj, "%s", class_dev->class_id);
 420         if (parent)
 421                 class_dev->kobj.parent = &parent->subsys.kset.kobj;
 422
 423         if ((error = kobject_add(&class_dev->kobj)))
 424                 goto register_done;
 425
 426         /* now take care of our own registration */
 427         if (parent) {
 428                 down_write(&parent->subsys.rwsem);
 429                 list_add_tail(&class_dev->node, &parent->children);
 430                 list_for_each_entry(class_intf, &parent->interfaces, node)
 431                         if (class_intf->add)
 432                                 class_intf->add(class_dev);
 433                 up_write(&parent->subsys.rwsem);
 434         }
 435         class_device_add_attrs(class_dev);
 436         class_device_dev_link(class_dev);
 437         class_device_driver_link(class_dev);
 438
 439  register_done:
 440         if (error && parent)
 441                 class_put(parent);
 442         class_device_put(class_dev);
 443         return error;
 444 }
 445
 446 int class_device_register(struct class_device *class_dev)
 447 {
 448         class_device_initialize(class_dev);
 449         return class_device_add(class_dev);
 450 }
 451
 452 void class_device_del(struct class_device *class_dev)
 453 {
 454         struct class * parent = class_dev->class;
 455         struct class_interface * class_intf;
 456
 457         if (parent) {
 458                 down_write(&parent->subsys.rwsem);
 459                 list_del_init(&class_dev->node);
 460                 list_for_each_entry(class_intf, &parent->interfaces, node)
 461                         if (class_intf->remove)
 462                                 class_intf->remove(class_dev);
 463                 up_write(&parent->subsys.rwsem);
 464         }
 465
 466         class_device_dev_unlink(class_dev);
 467         class_device_driver_unlink(class_dev);
 468         class_device_remove_attrs(class_dev);
 469
 470         kobject_del(&class_dev->kobj);
 471
 472         if (parent)
 473                 class_put(parent);
 474 }
 475
 476 void class_device_unregister(struct class_device *class_dev)
 477 {
 478         pr_debug("CLASS: Unregistering class device. ID = '%s'\n",
 479                  class_dev->class_id);
 480         class_device_del(class_dev);
 481         class_device_put(class_dev);
 482 }
 483
 484 int class_device_rename(struct class_device *class_dev, char *new_name)
 485 {
 486         int error = 0;
 487
 488         class_dev = class_device_get(class_dev);
 489         if (!class_dev)
 490                 return -EINVAL;
 491
 492         pr_debug("CLASS: renaming '%s' to '%s'\n", class_dev->class_id,
 493                  new_name);
 494
 495         strlcpy(class_dev->class_id, new_name, KOBJ_NAME_LEN);
 496
 497         error = kobject_rename(&class_dev->kobj, new_name);
 498
 499         class_device_put(class_dev);
 500
 501         return error;
 502 }
 503
 504 struct class_device * class_device_get(struct class_device *class_dev)
 505 {
 506         if (class_dev)
 507                 return to_class_dev(kobject_get(&class_dev->kobj));
 508         return NULL;
 509 }
 510
 511 void class_device_put(struct class_device *class_dev)
 512 {
 513         kobject_put(&class_dev->kobj);
 514 }
 515
 516
 517 int class_interface_register(struct class_interface *class_intf)
 518 {
 519         struct class * parent;
 520         struct class_device * class_dev;
 521
 522         if (!class_intf || !class_intf->class)
 523                 return -ENODEV;
 524
 525         parent = class_get(class_intf->class);
 526         if (!parent)
 527                 return -EINVAL;
 528
 529         down_write(&parent->subsys.rwsem);
 530         list_add_tail(&class_intf->node, &parent->interfaces);
 531
 532         if (class_intf->add) {
 533                 list_for_each_entry(class_dev, &parent->children, node)
 534                         class_intf->add(class_dev);
 535         }
 536         up_write(&parent->subsys.rwsem);
 537
 538         return 0;
 539 }
 540
 541 void class_interface_unregister(struct class_interface *class_intf)
 542 {
 543         struct class * parent = class_intf->class;
 544         struct class_device *class_dev;
 545
 546         if (!parent)
 547                 return;
 548
 549         down_write(&parent->subsys.rwsem);
 550         list_del_init(&class_intf->node);
 551
 552         if (class_intf->remove) {
 553                 list_for_each_entry(class_dev, &parent->children, node)
 554                         class_intf->remove(class_dev);
 555         }
 556         up_write(&parent->subsys.rwsem);
 557
 558         class_put(parent);
 559 }
 560
 561
 562
 563 int __init classes_init(void)
 564 {
 565         int retval;
 566
 567         retval = subsystem_register(&class_subsys);
 568         if (retval)
 569                 return retval;
 570
 571         /* ick, this is ugly, the things we go through to keep from showing up
 572          * in sysfs... */
 573         subsystem_init(&class_obj_subsys);
 574         if (!class_obj_subsys.kset.subsys)
 575                         class_obj_subsys.kset.subsys = &class_obj_subsys;
 576         return 0;
 577 }
 578
 579 EXPORT_SYMBOL_GPL(class_create_file);
 580 EXPORT_SYMBOL_GPL(class_remove_file);
 581 EXPORT_SYMBOL_GPL(class_register);
 582 EXPORT_SYMBOL_GPL(class_unregister);
 583 EXPORT_SYMBOL_GPL(class_get);
 584 EXPORT_SYMBOL_GPL(class_put);
 585
 586 EXPORT_SYMBOL_GPL(class_device_register);
 587 EXPORT_SYMBOL_GPL(class_device_unregister);
 588 EXPORT_SYMBOL_GPL(class_device_initialize);
 589 EXPORT_SYMBOL_GPL(class_device_add);
 590 EXPORT_SYMBOL_GPL(class_device_del);
 591 EXPORT_SYMBOL_GPL(class_device_get);
 592 EXPORT_SYMBOL_GPL(class_device_put);
 593 EXPORT_SYMBOL_GPL(class_device_create_file);
 594 EXPORT_SYMBOL_GPL(class_device_remove_file);
 595 EXPORT_SYMBOL_GPL(class_device_create_bin_file);
 596 EXPORT_SYMBOL_GPL(class_device_remove_bin_file);
 597
 598 EXPORT_SYMBOL_GPL(class_interface_register);
 599 EXPORT_SYMBOL_GPL(class_interface_unregister);