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 <linux/err.h>
  20 #include "base.h"
  21
  22 #define to_class_attr(_attr) container_of(_attr, struct class_attribute, attr)
  23 #define to_class(obj) container_of(obj, struct class, subsys.kset.kobj)
  24
  25 static ssize_t
  26 class_attr_show(struct kobject * kobj, struct attribute * attr, char * buf)
  27 {
  28         struct class_attribute * class_attr = to_class_attr(attr);
  29         struct class * dc = to_class(kobj);
  30         ssize_t ret = -EIO;
  31
  32         if (class_attr->show)
  33                 ret = class_attr->show(dc, buf);
  34         return ret;
  35 }
  36
  37 static ssize_t
  38 class_attr_store(struct kobject * kobj, struct attribute * attr,
  39                  const char * buf, size_t count)
  40 {
  41         struct class_attribute * class_attr = to_class_attr(attr);
  42         struct class * dc = to_class(kobj);
  43         ssize_t ret = -EIO;
  44
  45         if (class_attr->store)
  46                 ret = class_attr->store(dc, buf, count);
  47         return ret;
  48 }
  49
  50 static void class_release(struct kobject * kobj)
  51 {
  52         struct class *class = to_class(kobj);
  53
  54         pr_debug("class '%s': release.\n", class->name);
  55
  56         if (class->class_release)
  57                 class->class_release(class);
  58         else
  59                 pr_debug("class '%s' does not have a release() function, "
  60                          "be careful\n", class->name);
  61 }
  62
  63 static struct sysfs_ops class_sysfs_ops = {
  64         .show   = class_attr_show,
  65         .store  = class_attr_store,
  66 };
  67
  68 static struct kobj_type ktype_class = {
  69         .sysfs_ops      = &class_sysfs_ops,
  70         .release        = class_release,
  71 };
  72
  73 /* Hotplug events for classes go to the class_obj subsys */
  74 static decl_subsys(class, &ktype_class, NULL);
  75
  76
  77 int class_create_file(struct class * cls, const struct class_attribute * attr)
  78 {
  79         int error;
  80         if (cls) {
  81                 error = sysfs_create_file(&cls->subsys.kset.kobj, &attr->attr);
  82         } else
  83                 error = -EINVAL;
  84         return error;
  85 }
  86
  87 void class_remove_file(struct class * cls, const struct class_attribute * attr)
  88 {
  89         if (cls)
  90                 sysfs_remove_file(&cls->subsys.kset.kobj, &attr->attr);
  91 }
  92
  93 struct class * class_get(struct class * cls)
  94 {
  95         if (cls)
  96                 return container_of(subsys_get(&cls->subsys), struct class, subsys);
  97         return NULL;
  98 }
  99
 100 void class_put(struct class * cls)
 101 {
 102         subsys_put(&cls->subsys);
 103 }
 104
 105
 106 static int add_class_attrs(struct class * cls)
 107 {
 108         int i;
 109         int error = 0;
 110
 111         if (cls->class_attrs) {
 112                 for (i = 0; attr_name(cls->class_attrs[i]); i++) {
 113                         error = class_create_file(cls,&cls->class_attrs[i]);
 114                         if (error)
 115                                 goto Err;
 116                 }
 117         }
 118  Done:
 119         return error;
 120  Err:
 121         while (--i >= 0)
 122                 class_remove_file(cls,&cls->class_attrs[i]);
 123         goto Done;
 124 }
 125
 126 static void remove_class_attrs(struct class * cls)
 127 {
 128         int i;
 129
 130         if (cls->class_attrs) {
 131                 for (i = 0; attr_name(cls->class_attrs[i]); i++)
 132                         class_remove_file(cls,&cls->class_attrs[i]);
 133         }
 134 }
 135
 136 int class_register(struct class * cls)
 137 {
 138         int error;
 139
 140         pr_debug("device class '%s': registering\n", cls->name);
 141
 142         INIT_LIST_HEAD(&cls->children);
 143         INIT_LIST_HEAD(&cls->interfaces);
 144         init_MUTEX(&cls->sem);
 145         error = kobject_set_name(&cls->subsys.kset.kobj, "%s", cls->name);
 146         if (error)
 147                 return error;
 148
 149         subsys_set_kset(cls, class_subsys);
 150
 151         error = subsystem_register(&cls->subsys);
 152         if (!error) {
 153                 error = add_class_attrs(class_get(cls));
 154                 class_put(cls);
 155         }
 156         return error;
 157 }
 158
 159 void class_unregister(struct class * cls)
 160 {
 161         pr_debug("device class '%s': unregistering\n", cls->name);
 162         remove_class_attrs(cls);
 163         subsystem_unregister(&cls->subsys);
 164 }
 165
 166 static void class_create_release(struct class *cls)
 167 {
 168         kfree(cls);
 169 }
 170
 171 static void class_device_create_release(struct class_device *class_dev)
 172 {
 173         kfree(class_dev);
 174 }
 175
 176 struct class *class_create(struct module *owner, char *name)
 177 {
 178         struct class *cls;
 179         int retval;
 180
 181         cls = kmalloc(sizeof(struct class), GFP_KERNEL);
 182         if (!cls) {
 183                 retval = -ENOMEM;
 184                 goto error;
 185         }
 186         memset(cls, 0x00, sizeof(struct class));
 187
 188         cls->name = name;
 189         cls->owner = owner;
 190         cls->class_release = class_create_release;
 191         cls->release = class_device_create_release;
 192
 193         retval = class_register(cls);
 194         if (retval)
 195                 goto error;
 196
 197         return cls;
 198
 199 error:
 200         kfree(cls);
 201         return ERR_PTR(retval);
 202 }
 203
 204 void class_destroy(struct class *cls)
 205 {
 206         if ((cls == NULL) || (IS_ERR(cls)))
 207                 return;
 208
 209         class_unregister(cls);
 210 }
 211
 212 /* Class Device Stuff */
 213
 214 int class_device_create_file(struct class_device * class_dev,
 215                              const struct class_device_attribute * attr)
 216 {
 217         int error = -EINVAL;
 218         if (class_dev)
 219                 error = sysfs_create_file(&class_dev->kobj, &attr->attr);
 220         return error;
 221 }
 222
 223 void class_device_remove_file(struct class_device * class_dev,
 224                               const struct class_device_attribute * attr)
 225 {
 226         if (class_dev)
 227                 sysfs_remove_file(&class_dev->kobj, &attr->attr);
 228 }
 229
 230 int class_device_create_bin_file(struct class_device *class_dev,
 231                                  struct bin_attribute *attr)
 232 {
 233         int error = -EINVAL;
 234         if (class_dev)
 235                 error = sysfs_create_bin_file(&class_dev->kobj, attr);
 236         return error;
 237 }
 238
 239 void class_device_remove_bin_file(struct class_device *class_dev,
 240                                   struct bin_attribute *attr)
 241 {
 242         if (class_dev)
 243                 sysfs_remove_bin_file(&class_dev->kobj, attr);
 244 }
 245
 246 static ssize_t
 247 class_device_attr_show(struct kobject * kobj, struct attribute * attr,
 248                        char * buf)
 249 {
 250         struct class_device_attribute * class_dev_attr = to_class_dev_attr(attr);
 251         struct class_device * cd = to_class_dev(kobj);
 252         ssize_t ret = 0;
 253
 254         if (class_dev_attr->show)
 255                 ret = class_dev_attr->show(cd, buf);
 256         return ret;
 257 }
 258
 259 static ssize_t
 260 class_device_attr_store(struct kobject * kobj, struct attribute * attr,
 261                         const char * buf, size_t count)
 262 {
 263         struct class_device_attribute * class_dev_attr = to_class_dev_attr(attr);
 264         struct class_device * cd = to_class_dev(kobj);
 265         ssize_t ret = 0;
 266
 267         if (class_dev_attr->store)
 268                 ret = class_dev_attr->store(cd, buf, count);
 269         return ret;
 270 }
 271
 272 static struct sysfs_ops class_dev_sysfs_ops = {
 273         .show   = class_device_attr_show,
 274         .store  = class_device_attr_store,
 275 };
 276
 277 static void class_dev_release(struct kobject * kobj)
 278 {
 279         struct class_device *cd = to_class_dev(kobj);
 280         struct class * cls = cd->class;
 281
 282         pr_debug("device class '%s': release.\n", cd->class_id);
 283
 284         if (cls->release)
 285                 cls->release(cd);
 286         else {
 287                 printk(KERN_ERR "Device class '%s' does not have a release() function, "
 288                         "it is broken and must be fixed.\n",
 289                         cd->class_id);
 290                 WARN_ON(1);
 291         }
 292 }
 293
 294 static struct kobj_type ktype_class_device = {
 295         .sysfs_ops      = &class_dev_sysfs_ops,
 296         .release        = class_dev_release,
 297 };
 298
 299 static int class_hotplug_filter(struct kset *kset, struct kobject *kobj)
 300 {
 301         struct kobj_type *ktype = get_ktype(kobj);
 302
 303         if (ktype == &ktype_class_device) {
 304                 struct class_device *class_dev = to_class_dev(kobj);
 305                 if (class_dev->class)
 306                         return 1;
 307         }
 308         return 0;
 309 }
 310
 311 static const char *class_hotplug_name(struct kset *kset, struct kobject *kobj)
 312 {
 313         struct class_device *class_dev = to_class_dev(kobj);
 314
 315         return class_dev->class->name;
 316 }
 317
 318 static int class_hotplug(struct kset *kset, struct kobject *kobj, char **envp,
 319                          int num_envp, char *buffer, int buffer_size)
 320 {
 321         struct class_device *class_dev = to_class_dev(kobj);
 322         int i = 0;
 323         int length = 0;
 324         int retval = 0;
 325
 326         pr_debug("%s - name = %s\n", __FUNCTION__, class_dev->class_id);
 327
 328         if (class_dev->dev) {
 329                 /* add physical device, backing this device  */
 330                 struct device *dev = class_dev->dev;
 331                 char *path = kobject_get_path(&dev->kobj, GFP_KERNEL);
 332
 333                 add_hotplug_env_var(envp, num_envp, &i, buffer, buffer_size,
 334                                     &length, "PHYSDEVPATH=%s", path);
 335                 kfree(path);
 336
 337                 if (dev->bus)
 338                         add_hotplug_env_var(envp, num_envp, &i,
 339                                             buffer, buffer_size, &length,
 340                                             "PHYSDEVBUS=%s", dev->bus->name);
 341
 342                 if (dev->driver)
 343                         add_hotplug_env_var(envp, num_envp, &i,
 344                                             buffer, buffer_size, &length,
 345                                             "PHYSDEVDRIVER=%s", dev->driver->name);
 346         }
 347
 348         if (MAJOR(class_dev->devt)) {
 349                 add_hotplug_env_var(envp, num_envp, &i,
 350                                     buffer, buffer_size, &length,
 351                                     "MAJOR=%u", MAJOR(class_dev->devt));
 352
 353                 add_hotplug_env_var(envp, num_envp, &i,
 354                                     buffer, buffer_size, &length,
 355                                     "MINOR=%u", MINOR(class_dev->devt));
 356         }
 357
 358         /* terminate, set to next free slot, shrink available space */
 359         envp[i] = NULL;
 360         envp = &envp[i];
 361         num_envp -= i;
 362         buffer = &buffer[length];
 363         buffer_size -= length;
 364
 365         if (class_dev->class->hotplug) {
 366                 /* have the bus specific function add its stuff */
 367                 retval = class_dev->class->hotplug (class_dev, envp, num_envp,
 368                                                     buffer, buffer_size);
 369                         if (retval) {
 370                         pr_debug ("%s - hotplug() returned %d\n",
 371                                   __FUNCTION__, retval);
 372                 }
 373         }
 374
 375         return retval;
 376 }
 377
 378 static struct kset_hotplug_ops class_hotplug_ops = {
 379         .filter =       class_hotplug_filter,
 380         .name =         class_hotplug_name,
 381         .hotplug =      class_hotplug,
 382 };
 383
 384 static decl_subsys(class_obj, &ktype_class_device, &class_hotplug_ops);
 385
 386
 387 static int class_device_add_attrs(struct class_device * cd)
 388 {
 389         int i;
 390         int error = 0;
 391         struct class * cls = cd->class;
 392
 393         if (cls->class_dev_attrs) {
 394                 for (i = 0; attr_name(cls->class_dev_attrs[i]); i++) {
 395                         error = class_device_create_file(cd,
 396                                                          &cls->class_dev_attrs[i]);
 397                         if (error)
 398                                 goto Err;
 399                 }
 400         }
 401  Done:
 402         return error;
 403  Err:
 404         while (--i >= 0)
 405                 class_device_remove_file(cd,&cls->class_dev_attrs[i]);
 406         goto Done;
 407 }
 408
 409 static void class_device_remove_attrs(struct class_device * cd)
 410 {
 411         int i;
 412         struct class * cls = cd->class;
 413
 414         if (cls->class_dev_attrs) {
 415                 for (i = 0; attr_name(cls->class_dev_attrs[i]); i++)
 416                         class_device_remove_file(cd,&cls->class_dev_attrs[i]);
 417         }
 418 }
 419
 420 static ssize_t show_dev(struct class_device *class_dev, char *buf)
 421 {
 422         return print_dev_t(buf, class_dev->devt);
 423 }
 424
 425 void class_device_initialize(struct class_device *class_dev)
 426 {
 427         kobj_set_kset_s(class_dev, class_obj_subsys);
 428         kobject_init(&class_dev->kobj);
 429         INIT_LIST_HEAD(&class_dev->node);
 430 }
 431
 432 int class_device_add(struct class_device *class_dev)
 433 {
 434         struct class * parent = NULL;
 435         struct class_interface * class_intf;
 436         int error;
 437
 438         class_dev = class_device_get(class_dev);
 439         if (!class_dev)
 440                 return -EINVAL;
 441
 442         if (!strlen(class_dev->class_id)) {
 443                 error = -EINVAL;
 444                 goto register_done;
 445         }
 446
 447         parent = class_get(class_dev->class);
 448
 449         pr_debug("CLASS: registering class device: ID = '%s'\n",
 450                  class_dev->class_id);
 451
 452         /* first, register with generic layer. */
 453         kobject_set_name(&class_dev->kobj, "%s", class_dev->class_id);
 454         if (parent)
 455                 class_dev->kobj.parent = &parent->subsys.kset.kobj;
 456
 457         if ((error = kobject_add(&class_dev->kobj)))
 458                 goto register_done;
 459
 460         /* add the needed attributes to this device */
 461         if (MAJOR(class_dev->devt)) {
 462                 struct class_device_attribute *attr;
 463                 attr = kmalloc(sizeof(*attr), GFP_KERNEL);
 464                 if (!attr) {
 465                         error = -ENOMEM;
 466                         kobject_del(&class_dev->kobj);
 467                         goto register_done;
 468                 }
 469                 memset(attr, sizeof(*attr), 0x00);
 470                 attr->attr.name = "dev";
 471                 attr->attr.mode = S_IRUGO;
 472                 attr->attr.owner = parent->owner;
 473                 attr->show = show_dev;
 474                 attr->store = NULL;
 475                 class_device_create_file(class_dev, attr);
 476                 class_dev->devt_attr = attr;
 477         }
 478
 479         class_device_add_attrs(class_dev);
 480         if (class_dev->dev)
 481                 sysfs_create_link(&class_dev->kobj,
 482                                   &class_dev->dev->kobj, "device");
 483
 484         /* notify any interfaces this device is now here */
 485         if (parent) {
 486                 down(&parent->sem);
 487                 list_add_tail(&class_dev->node, &parent->children);
 488                 list_for_each_entry(class_intf, &parent->interfaces, node)
 489                         if (class_intf->add)
 490                                 class_intf->add(class_dev);
 491                 up(&parent->sem);
 492         }
 493         kobject_hotplug(&class_dev->kobj, KOBJ_ADD);
 494
 495  register_done:
 496         if (error && parent)
 497                 class_put(parent);
 498         class_device_put(class_dev);
 499         return error;
 500 }
 501
 502 int class_device_register(struct class_device *class_dev)
 503 {
 504         class_device_initialize(class_dev);
 505         return class_device_add(class_dev);
 506 }
 507
 508 struct class_device *class_device_create(struct class *cls, dev_t devt,
 509                                          struct device *device, char *fmt, ...)
 510 {
 511         va_list args;
 512         struct class_device *class_dev = NULL;
 513         int retval = -ENODEV;
 514
 515         if (cls == NULL || IS_ERR(cls))
 516                 goto error;
 517
 518         class_dev = kmalloc(sizeof(struct class_device), GFP_KERNEL);
 519         if (!class_dev) {
 520                 retval = -ENOMEM;
 521                 goto error;
 522         }
 523         memset(class_dev, 0x00, sizeof(struct class_device));
 524
 525         class_dev->devt = devt;
 526         class_dev->dev = device;
 527         class_dev->class = cls;
 528
 529         va_start(args, fmt);
 530         vsnprintf(class_dev->class_id, BUS_ID_SIZE, fmt, args);
 531         va_end(args);
 532         retval = class_device_register(class_dev);
 533         if (retval)
 534                 goto error;
 535
 536         return class_dev;
 537
 538 error:
 539         kfree(class_dev);
 540         return ERR_PTR(retval);
 541 }
 542
 543 void class_device_del(struct class_device *class_dev)
 544 {
 545         struct class * parent = class_dev->class;
 546         struct class_interface * class_intf;
 547
 548         if (parent) {
 549                 down(&parent->sem);
 550                 list_del_init(&class_dev->node);
 551                 list_for_each_entry(class_intf, &parent->interfaces, node)
 552                         if (class_intf->remove)
 553                                 class_intf->remove(class_dev);
 554                 up(&parent->sem);
 555         }
 556
 557         if (class_dev->dev)
 558                 sysfs_remove_link(&class_dev->kobj, "device");
 559         if (class_dev->devt_attr) {
 560                 class_device_remove_file(class_dev, class_dev->devt_attr);
 561                 kfree(class_dev->devt_attr);
 562                 class_dev->devt_attr = NULL;
 563         }
 564         class_device_remove_attrs(class_dev);
 565
 566         kobject_hotplug(&class_dev->kobj, KOBJ_REMOVE);
 567         kobject_del(&class_dev->kobj);
 568
 569         if (parent)
 570                 class_put(parent);
 571 }
 572
 573 void class_device_unregister(struct class_device *class_dev)
 574 {
 575         pr_debug("CLASS: Unregistering class device. ID = '%s'\n",
 576                  class_dev->class_id);
 577         class_device_del(class_dev);
 578         class_device_put(class_dev);
 579 }
 580
 581 void class_device_destroy(struct class *cls, dev_t devt)
 582 {
 583         struct class_device *class_dev = NULL;
 584         struct class_device *class_dev_tmp;
 585
 586         down(&cls->sem);
 587         list_for_each_entry(class_dev_tmp, &cls->children, node) {
 588                 if (class_dev_tmp->devt == devt) {
 589                         class_dev = class_dev_tmp;
 590                         break;
 591                 }
 592         }
 593         up(&cls->sem);
 594
 595         if (class_dev)
 596                 class_device_unregister(class_dev);
 597 }
 598
 599 int class_device_rename(struct class_device *class_dev, char *new_name)
 600 {
 601         int error = 0;
 602
 603         class_dev = class_device_get(class_dev);
 604         if (!class_dev)
 605                 return -EINVAL;
 606
 607         pr_debug("CLASS: renaming '%s' to '%s'\n", class_dev->class_id,
 608                  new_name);
 609
 610         strlcpy(class_dev->class_id, new_name, KOBJ_NAME_LEN);
 611
 612         error = kobject_rename(&class_dev->kobj, new_name);
 613
 614         class_device_put(class_dev);
 615
 616         return error;
 617 }
 618
 619 struct class_device * class_device_get(struct class_device *class_dev)
 620 {
 621         if (class_dev)
 622                 return to_class_dev(kobject_get(&class_dev->kobj));
 623         return NULL;
 624 }
 625
 626 void class_device_put(struct class_device *class_dev)
 627 {
 628         kobject_put(&class_dev->kobj);
 629 }
 630
 631
 632 int class_interface_register(struct class_interface *class_intf)
 633 {
 634         struct class *parent;
 635         struct class_device *class_dev;
 636
 637         if (!class_intf || !class_intf->class)
 638                 return -ENODEV;
 639
 640         parent = class_get(class_intf->class);
 641         if (!parent)
 642                 return -EINVAL;
 643
 644         down(&parent->sem);
 645         list_add_tail(&class_intf->node, &parent->interfaces);
 646         if (class_intf->add) {
 647                 list_for_each_entry(class_dev, &parent->children, node)
 648                         class_intf->add(class_dev);
 649         }
 650         up(&parent->sem);
 651
 652         return 0;
 653 }
 654
 655 void class_interface_unregister(struct class_interface *class_intf)
 656 {
 657         struct class * parent = class_intf->class;
 658         struct class_device *class_dev;
 659
 660         if (!parent)
 661                 return;
 662
 663         down(&parent->sem);
 664         list_del_init(&class_intf->node);
 665         if (class_intf->remove) {
 666                 list_for_each_entry(class_dev, &parent->children, node)
 667                         class_intf->remove(class_dev);
 668         }
 669         up(&parent->sem);
 670
 671         class_put(parent);
 672 }
 673
 674
 675
 676 int __init classes_init(void)
 677 {
 678         int retval;
 679
 680         retval = subsystem_register(&class_subsys);
 681         if (retval)
 682                 return retval;
 683
 684         /* ick, this is ugly, the things we go through to keep from showing up
 685          * in sysfs... */
 686         subsystem_init(&class_obj_subsys);
 687         if (!class_obj_subsys.kset.subsys)
 688                         class_obj_subsys.kset.subsys = &class_obj_subsys;
 689         return 0;
 690 }
 691
 692 EXPORT_SYMBOL_GPL(class_create_file);
 693 EXPORT_SYMBOL_GPL(class_remove_file);
 694 EXPORT_SYMBOL_GPL(class_register);
 695 EXPORT_SYMBOL_GPL(class_unregister);
 696 EXPORT_SYMBOL_GPL(class_get);
 697 EXPORT_SYMBOL_GPL(class_put);
 698 EXPORT_SYMBOL_GPL(class_create);
 699 EXPORT_SYMBOL_GPL(class_destroy);
 700
 701 EXPORT_SYMBOL_GPL(class_device_register);
 702 EXPORT_SYMBOL_GPL(class_device_unregister);
 703 EXPORT_SYMBOL_GPL(class_device_initialize);
 704 EXPORT_SYMBOL_GPL(class_device_add);
 705 EXPORT_SYMBOL_GPL(class_device_del);
 706 EXPORT_SYMBOL_GPL(class_device_get);
 707 EXPORT_SYMBOL_GPL(class_device_put);
 708 EXPORT_SYMBOL_GPL(class_device_create);
 709 EXPORT_SYMBOL_GPL(class_device_destroy);
 710 EXPORT_SYMBOL_GPL(class_device_create_file);
 711 EXPORT_SYMBOL_GPL(class_device_remove_file);
 712 EXPORT_SYMBOL_GPL(class_device_create_bin_file);
 713 EXPORT_SYMBOL_GPL(class_device_remove_bin_file);
 714
 715 EXPORT_SYMBOL_GPL(class_interface_register);
 716 EXPORT_SYMBOL_GPL(class_interface_unregister);