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 static int class_device_dev_link(struct class_device * class_dev)
 183 {
 184         if (class_dev->dev)
 185                 return sysfs_create_link(&class_dev->kobj,
 186                                          &class_dev->dev->kobj, "device");
 187         return 0;
 188 }
 189
 190 static void class_device_dev_unlink(struct class_device * class_dev)
 191 {
 192         sysfs_remove_link(&class_dev->kobj, "device");
 193 }
 194
 195 static int class_device_driver_link(struct class_device * class_dev)
 196 {
 197         if ((class_dev->dev) && (class_dev->dev->driver))
 198                 return sysfs_create_link(&class_dev->kobj,
 199                                          &class_dev->dev->driver->kobj, "driver");
 200         return 0;
 201 }
 202
 203 static void class_device_driver_unlink(struct class_device * class_dev)
 204 {
 205         sysfs_remove_link(&class_dev->kobj, "driver");
 206 }
 207
 208
 209 static ssize_t
 210 class_device_attr_show(struct kobject * kobj, struct attribute * attr,
 211                        char * buf)
 212 {
 213         struct class_device_attribute * class_dev_attr = to_class_dev_attr(attr);
 214         struct class_device * cd = to_class_dev(kobj);
 215         ssize_t ret = 0;
 216
 217         if (class_dev_attr->show)
 218                 ret = class_dev_attr->show(cd, buf);
 219         return ret;
 220 }
 221
 222 static ssize_t
 223 class_device_attr_store(struct kobject * kobj, struct attribute * attr,
 224                         const char * buf, size_t count)
 225 {
 226         struct class_device_attribute * class_dev_attr = to_class_dev_attr(attr);
 227         struct class_device * cd = to_class_dev(kobj);
 228         ssize_t ret = 0;
 229
 230         if (class_dev_attr->store)
 231                 ret = class_dev_attr->store(cd, buf, count);
 232         return ret;
 233 }
 234
 235 static struct sysfs_ops class_dev_sysfs_ops = {
 236         .show   = class_device_attr_show,
 237         .store  = class_device_attr_store,
 238 };
 239
 240 static void class_dev_release(struct kobject * kobj)
 241 {
 242         struct class_device *cd = to_class_dev(kobj);
 243         struct class * cls = cd->class;
 244
 245         pr_debug("device class '%s': release.\n", cd->class_id);
 246
 247         if (cls->release)
 248                 cls->release(cd);
 249         else {
 250                 printk(KERN_ERR "Device class '%s' does not have a release() function, "
 251                         "it is broken and must be fixed.\n",
 252                         cd->class_id);
 253                 WARN_ON(1);
 254         }
 255 }
 256
 257 static struct kobj_type ktype_class_device = {
 258         .sysfs_ops      = &class_dev_sysfs_ops,
 259         .release        = class_dev_release,
 260 };
 261
 262 static int class_hotplug_filter(struct kset *kset, struct kobject *kobj)
 263 {
 264         struct kobj_type *ktype = get_ktype(kobj);
 265
 266         if (ktype == &ktype_class_device) {
 267                 struct class_device *class_dev = to_class_dev(kobj);
 268                 if (class_dev->class)
 269                         return 1;
 270         }
 271         return 0;
 272 }
 273
 274 static char *class_hotplug_name(struct kset *kset, struct kobject *kobj)
 275 {
 276         struct class_device *class_dev = to_class_dev(kobj);
 277
 278         return class_dev->class->name;
 279 }
 280
 281 static int class_hotplug(struct kset *kset, struct kobject *kobj, char **envp,
 282                          int num_envp, char *buffer, int buffer_size)
 283 {
 284         struct class_device *class_dev = to_class_dev(kobj);
 285         int retval = 0;
 286         int i = 0;
 287         int length = 0;
 288
 289         pr_debug("%s - name = %s\n", __FUNCTION__, class_dev->class_id);
 290
 291         if (class_dev->dev) {
 292                 /* add physical device, backing this device  */
 293                 struct device *dev = class_dev->dev;
 294                 char *path = kobject_get_path(&dev->kobj, GFP_KERNEL);
 295
 296                 add_hotplug_env_var(envp, num_envp, &i, buffer, buffer_size,
 297                                     &length, "PHYSDEVPATH=%s", path);
 298                 kfree(path);
 299
 300                 /* add bus name of physical device */
 301                 if (dev->bus)
 302                         add_hotplug_env_var(envp, num_envp, &i,
 303                                             buffer, buffer_size, &length,
 304                                             "PHYSDEVBUS=%s", dev->bus->name);
 305
 306                 /* add driver name of physical device */
 307                 if (dev->driver)
 308                         add_hotplug_env_var(envp, num_envp, &i,
 309                                             buffer, buffer_size, &length,
 310                                             "PHYSDEVDRIVER=%s", dev->driver->name);
 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
 320         if (class_dev->class->hotplug) {
 321                 /* have the bus specific function add its stuff */
 322                 retval = class_dev->class->hotplug (class_dev, envp, num_envp,
 323                                                     buffer, buffer_size);
 324                         if (retval) {
 325                         pr_debug ("%s - hotplug() returned %d\n",
 326                                   __FUNCTION__, retval);
 327                 }
 328         }
 329
 330         return retval;
 331 }
 332
 333 static struct kset_hotplug_ops class_hotplug_ops = {
 334         .filter =       class_hotplug_filter,
 335         .name =         class_hotplug_name,
 336         .hotplug =      class_hotplug,
 337 };
 338
 339 static decl_subsys(class_obj, &ktype_class_device, &class_hotplug_ops);
 340
 341
 342 static int class_device_add_attrs(struct class_device * cd)
 343 {
 344         int i;
 345         int error = 0;
 346         struct class * cls = cd->class;
 347
 348         if (cls->class_dev_attrs) {
 349                 for (i = 0; attr_name(cls->class_dev_attrs[i]); i++) {
 350                         error = class_device_create_file(cd,
 351                                                          &cls->class_dev_attrs[i]);
 352                         if (error)
 353                                 goto Err;
 354                 }
 355         }
 356  Done:
 357         return error;
 358  Err:
 359         while (--i >= 0)
 360                 class_device_remove_file(cd,&cls->class_dev_attrs[i]);
 361         goto Done;
 362 }
 363
 364 static void class_device_remove_attrs(struct class_device * cd)
 365 {
 366         int i;
 367         struct class * cls = cd->class;
 368
 369         if (cls->class_dev_attrs) {
 370                 for (i = 0; attr_name(cls->class_dev_attrs[i]); i++)
 371                         class_device_remove_file(cd,&cls->class_dev_attrs[i]);
 372         }
 373 }
 374
 375 void class_device_initialize(struct class_device *class_dev)
 376 {
 377         kobj_set_kset_s(class_dev, class_obj_subsys);
 378         kobject_init(&class_dev->kobj);
 379         INIT_LIST_HEAD(&class_dev->node);
 380 }
 381
 382 int class_device_add(struct class_device *class_dev)
 383 {
 384         struct class * parent = NULL;
 385         struct class_interface * class_intf;
 386         int error;
 387
 388         class_dev = class_device_get(class_dev);
 389         if (!class_dev)
 390                 return -EINVAL;
 391
 392         if (!strlen(class_dev->class_id)) {
 393                 error = -EINVAL;
 394                 goto register_done;
 395         }
 396
 397         parent = class_get(class_dev->class);
 398
 399         pr_debug("CLASS: registering class device: ID = '%s'\n",
 400                  class_dev->class_id);
 401
 402         /* first, register with generic layer. */
 403         kobject_set_name(&class_dev->kobj, "%s", class_dev->class_id);
 404         if (parent)
 405                 class_dev->kobj.parent = &parent->subsys.kset.kobj;
 406
 407         if ((error = kobject_add(&class_dev->kobj)))
 408                 goto register_done;
 409
 410         /* now take care of our own registration */
 411         if (parent) {
 412                 down_write(&parent->subsys.rwsem);
 413                 list_add_tail(&class_dev->node, &parent->children);
 414                 list_for_each_entry(class_intf, &parent->interfaces, node)
 415                         if (class_intf->add)
 416                                 class_intf->add(class_dev);
 417                 up_write(&parent->subsys.rwsem);
 418         }
 419         class_device_add_attrs(class_dev);
 420         class_device_dev_link(class_dev);
 421         class_device_driver_link(class_dev);
 422
 423  register_done:
 424         if (error && parent)
 425                 class_put(parent);
 426         class_device_put(class_dev);
 427         return error;
 428 }
 429
 430 int class_device_register(struct class_device *class_dev)
 431 {
 432         class_device_initialize(class_dev);
 433         return class_device_add(class_dev);
 434 }
 435
 436 void class_device_del(struct class_device *class_dev)
 437 {
 438         struct class * parent = class_dev->class;
 439         struct class_interface * class_intf;
 440
 441         if (parent) {
 442                 down_write(&parent->subsys.rwsem);
 443                 list_del_init(&class_dev->node);
 444                 list_for_each_entry(class_intf, &parent->interfaces, node)
 445                         if (class_intf->remove)
 446                                 class_intf->remove(class_dev);
 447                 up_write(&parent->subsys.rwsem);
 448         }
 449
 450         class_device_dev_unlink(class_dev);
 451         class_device_driver_unlink(class_dev);
 452         class_device_remove_attrs(class_dev);
 453
 454         kobject_del(&class_dev->kobj);
 455
 456         if (parent)
 457                 class_put(parent);
 458 }
 459
 460 void class_device_unregister(struct class_device *class_dev)
 461 {
 462         pr_debug("CLASS: Unregistering class device. ID = '%s'\n",
 463                  class_dev->class_id);
 464         class_device_del(class_dev);
 465         class_device_put(class_dev);
 466 }
 467
 468 int class_device_rename(struct class_device *class_dev, char *new_name)
 469 {
 470         int error = 0;
 471
 472         class_dev = class_device_get(class_dev);
 473         if (!class_dev)
 474                 return -EINVAL;
 475
 476         pr_debug("CLASS: renaming '%s' to '%s'\n", class_dev->class_id,
 477                  new_name);
 478
 479         strlcpy(class_dev->class_id, new_name, KOBJ_NAME_LEN);
 480
 481         error = kobject_rename(&class_dev->kobj, new_name);
 482
 483         class_device_put(class_dev);
 484
 485         return error;
 486 }
 487
 488 struct class_device * class_device_get(struct class_device *class_dev)
 489 {
 490         if (class_dev)
 491                 return to_class_dev(kobject_get(&class_dev->kobj));
 492         return NULL;
 493 }
 494
 495 void class_device_put(struct class_device *class_dev)
 496 {
 497         kobject_put(&class_dev->kobj);
 498 }
 499
 500
 501 int class_interface_register(struct class_interface *class_intf)
 502 {
 503         struct class * parent;
 504         struct class_device * class_dev;
 505
 506         if (!class_intf || !class_intf->class)
 507                 return -ENODEV;
 508
 509         parent = class_get(class_intf->class);
 510         if (!parent)
 511                 return -EINVAL;
 512
 513         down_write(&parent->subsys.rwsem);
 514         list_add_tail(&class_intf->node, &parent->interfaces);
 515
 516         if (class_intf->add) {
 517                 list_for_each_entry(class_dev, &parent->children, node)
 518                         class_intf->add(class_dev);
 519         }
 520         up_write(&parent->subsys.rwsem);
 521
 522         return 0;
 523 }
 524
 525 void class_interface_unregister(struct class_interface *class_intf)
 526 {
 527         struct class * parent = class_intf->class;
 528         struct class_device *class_dev;
 529
 530         if (!parent)
 531                 return;
 532
 533         down_write(&parent->subsys.rwsem);
 534         list_del_init(&class_intf->node);
 535
 536         if (class_intf->remove) {
 537                 list_for_each_entry(class_dev, &parent->children, node)
 538                         class_intf->remove(class_dev);
 539         }
 540         up_write(&parent->subsys.rwsem);
 541
 542         class_put(parent);
 543 }
 544
 545
 546
 547 int __init classes_init(void)
 548 {
 549         int retval;
 550
 551         retval = subsystem_register(&class_subsys);
 552         if (retval)
 553                 return retval;
 554
 555         /* ick, this is ugly, the things we go through to keep from showing up
 556          * in sysfs... */
 557         subsystem_init(&class_obj_subsys);
 558         if (!class_obj_subsys.kset.subsys)
 559                         class_obj_subsys.kset.subsys = &class_obj_subsys;
 560         return 0;
 561 }
 562
 563 EXPORT_SYMBOL_GPL(class_create_file);
 564 EXPORT_SYMBOL_GPL(class_remove_file);
 565 EXPORT_SYMBOL_GPL(class_register);
 566 EXPORT_SYMBOL_GPL(class_unregister);
 567 EXPORT_SYMBOL_GPL(class_get);
 568 EXPORT_SYMBOL_GPL(class_put);
 569
 570 EXPORT_SYMBOL_GPL(class_device_register);
 571 EXPORT_SYMBOL_GPL(class_device_unregister);
 572 EXPORT_SYMBOL_GPL(class_device_initialize);
 573 EXPORT_SYMBOL_GPL(class_device_add);
 574 EXPORT_SYMBOL_GPL(class_device_del);
 575 EXPORT_SYMBOL_GPL(class_device_get);
 576 EXPORT_SYMBOL_GPL(class_device_put);
 577 EXPORT_SYMBOL_GPL(class_device_create_file);
 578 EXPORT_SYMBOL_GPL(class_device_remove_file);
 579
 580 EXPORT_SYMBOL_GPL(class_interface_register);
 581 EXPORT_SYMBOL_GPL(class_interface_unregister);