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