1 /* 2 * drivers/base/core.c - core driver model code (device registration, etc) 3 * 4 * Copyright (c) 2002-3 Patrick Mochel 5 * Copyright (c) 2002-3 Open Source Development Labs 6 * Copyright (c) 2006 Greg Kroah-Hartman <gregkh@suse.de> 7 * Copyright (c) 2006 Novell, Inc. 8 * 9 * This file is released under the GPLv2 10 * 11 */ 12 13 #include <linux/device.h> 14 #include <linux/err.h> 15 #include <linux/init.h> 16 #include <linux/module.h> 17 #include <linux/slab.h> 18 #include <linux/string.h> 19 #include <linux/kdev_t.h> 20 #include <linux/notifier.h> 21 22 #include <asm/semaphore.h> 23 24 #include "base.h" 25 #include "power/power.h" 26 27 int (*platform_notify)(struct device * dev) = NULL; 28 int (*platform_notify_remove)(struct device * dev) = NULL; 29 30 /* 31 * sysfs bindings for devices. 32 */ 33 34 /** 35 * dev_driver_string - Return a device's driver name, if at all possible 36 * @dev: struct device to get the name of 37 * 38 * Will return the device's driver's name if it is bound to a device. If 39 * the device is not bound to a device, it will return the name of the bus 40 * it is attached to. If it is not attached to a bus either, an empty 41 * string will be returned. 42 */ 43 const char *dev_driver_string(struct device *dev) 44 { 45 return dev->driver ? dev->driver->name : 46 (dev->bus ? dev->bus->name : 47 (dev->class ? dev->class->name : "")); 48 } 49 EXPORT_SYMBOL(dev_driver_string); 50 51 #define to_dev(obj) container_of(obj, struct device, kobj) 52 #define to_dev_attr(_attr) container_of(_attr, struct device_attribute, attr) 53 54 static ssize_t 55 dev_attr_show(struct kobject * kobj, struct attribute * attr, char * buf) 56 { 57 struct device_attribute * dev_attr = to_dev_attr(attr); 58 struct device * dev = to_dev(kobj); 59 ssize_t ret = -EIO; 60 61 if (dev_attr->show) 62 ret = dev_attr->show(dev, dev_attr, buf); 63 return ret; 64 } 65 66 static ssize_t 67 dev_attr_store(struct kobject * kobj, struct attribute * attr, 68 const char * buf, size_t count) 69 { 70 struct device_attribute * dev_attr = to_dev_attr(attr); 71 struct device * dev = to_dev(kobj); 72 ssize_t ret = -EIO; 73 74 if (dev_attr->store) 75 ret = dev_attr->store(dev, dev_attr, buf, count); 76 return ret; 77 } 78 79 static struct sysfs_ops dev_sysfs_ops = { 80 .show = dev_attr_show, 81 .store = dev_attr_store, 82 }; 83 84 85 /** 86 * device_release - free device structure. 87 * @kobj: device's kobject. 88 * 89 * This is called once the reference count for the object 90 * reaches 0. We forward the call to the device's release 91 * method, which should handle actually freeing the structure. 92 */ 93 static void device_release(struct kobject * kobj) 94 { 95 struct device * dev = to_dev(kobj); 96 97 if (dev->release) 98 dev->release(dev); 99 else if (dev->type && dev->type->release) 100 dev->type->release(dev); 101 else if (dev->class && dev->class->dev_release) 102 dev->class->dev_release(dev); 103 else { 104 printk(KERN_ERR "Device '%s' does not have a release() function, " 105 "it is broken and must be fixed.\n", 106 dev->bus_id); 107 WARN_ON(1); 108 } 109 } 110 111 static struct kobj_type ktype_device = { 112 .release = device_release, 113 .sysfs_ops = &dev_sysfs_ops, 114 }; 115 116 117 static int dev_uevent_filter(struct kset *kset, struct kobject *kobj) 118 { 119 struct kobj_type *ktype = get_ktype(kobj); 120 121 if (ktype == &ktype_device) { 122 struct device *dev = to_dev(kobj); 123 if (dev->uevent_suppress) 124 return 0; 125 if (dev->bus) 126 return 1; 127 if (dev->class) 128 return 1; 129 } 130 return 0; 131 } 132 133 static const char *dev_uevent_name(struct kset *kset, struct kobject *kobj) 134 { 135 struct device *dev = to_dev(kobj); 136 137 if (dev->bus) 138 return dev->bus->name; 139 if (dev->class) 140 return dev->class->name; 141 return NULL; 142 } 143 144 static int dev_uevent(struct kset *kset, struct kobject *kobj, char **envp, 145 int num_envp, char *buffer, int buffer_size) 146 { 147 struct device *dev = to_dev(kobj); 148 int i = 0; 149 int length = 0; 150 int retval = 0; 151 152 /* add the major/minor if present */ 153 if (MAJOR(dev->devt)) { 154 add_uevent_var(envp, num_envp, &i, 155 buffer, buffer_size, &length, 156 "MAJOR=%u", MAJOR(dev->devt)); 157 add_uevent_var(envp, num_envp, &i, 158 buffer, buffer_size, &length, 159 "MINOR=%u", MINOR(dev->devt)); 160 } 161 162 if (dev->type && dev->type->name) 163 add_uevent_var(envp, num_envp, &i, 164 buffer, buffer_size, &length, 165 "DEVTYPE=%s", dev->type->name); 166 167 if (dev->driver) 168 add_uevent_var(envp, num_envp, &i, 169 buffer, buffer_size, &length, 170 "DRIVER=%s", dev->driver->name); 171 172 #ifdef CONFIG_SYSFS_DEPRECATED 173 if (dev->class) { 174 struct device *parent = dev->parent; 175 176 /* find first bus device in parent chain */ 177 while (parent && !parent->bus) 178 parent = parent->parent; 179 if (parent && parent->bus) { 180 const char *path; 181 182 path = kobject_get_path(&parent->kobj, GFP_KERNEL); 183 add_uevent_var(envp, num_envp, &i, 184 buffer, buffer_size, &length, 185 "PHYSDEVPATH=%s", path); 186 kfree(path); 187 188 add_uevent_var(envp, num_envp, &i, 189 buffer, buffer_size, &length, 190 "PHYSDEVBUS=%s", parent->bus->name); 191 192 if (parent->driver) 193 add_uevent_var(envp, num_envp, &i, 194 buffer, buffer_size, &length, 195 "PHYSDEVDRIVER=%s", parent->driver->name); 196 } 197 } else if (dev->bus) { 198 add_uevent_var(envp, num_envp, &i, 199 buffer, buffer_size, &length, 200 "PHYSDEVBUS=%s", dev->bus->name); 201 202 if (dev->driver) 203 add_uevent_var(envp, num_envp, &i, 204 buffer, buffer_size, &length, 205 "PHYSDEVDRIVER=%s", dev->driver->name); 206 } 207 #endif 208 209 /* terminate, set to next free slot, shrink available space */ 210 envp[i] = NULL; 211 envp = &envp[i]; 212 num_envp -= i; 213 buffer = &buffer[length]; 214 buffer_size -= length; 215 216 if (dev->bus && dev->bus->uevent) { 217 /* have the bus specific function add its stuff */ 218 retval = dev->bus->uevent(dev, envp, num_envp, buffer, buffer_size); 219 if (retval) 220 pr_debug ("%s: bus uevent() returned %d\n", 221 __FUNCTION__, retval); 222 } 223 224 if (dev->class && dev->class->dev_uevent) { 225 /* have the class specific function add its stuff */ 226 retval = dev->class->dev_uevent(dev, envp, num_envp, buffer, buffer_size); 227 if (retval) 228 pr_debug("%s: class uevent() returned %d\n", 229 __FUNCTION__, retval); 230 } 231 232 if (dev->type && dev->type->uevent) { 233 /* have the device type specific fuction add its stuff */ 234 retval = dev->type->uevent(dev, envp, num_envp, buffer, buffer_size); 235 if (retval) 236 pr_debug("%s: dev_type uevent() returned %d\n", 237 __FUNCTION__, retval); 238 } 239 240 return retval; 241 } 242 243 static struct kset_uevent_ops device_uevent_ops = { 244 .filter = dev_uevent_filter, 245 .name = dev_uevent_name, 246 .uevent = dev_uevent, 247 }; 248 249 static ssize_t show_uevent(struct device *dev, struct device_attribute *attr, 250 char *buf) 251 { 252 struct kobject *top_kobj; 253 struct kset *kset; 254 char *envp[32]; 255 char *data = NULL; 256 char *pos; 257 int i; 258 size_t count = 0; 259 int retval; 260 261 /* search the kset, the device belongs to */ 262 top_kobj = &dev->kobj; 263 if (!top_kobj->kset && top_kobj->parent) { 264 do { 265 top_kobj = top_kobj->parent; 266 } while (!top_kobj->kset && top_kobj->parent); 267 } 268 if (!top_kobj->kset) 269 goto out; 270 kset = top_kobj->kset; 271 if (!kset->uevent_ops || !kset->uevent_ops->uevent) 272 goto out; 273 274 /* respect filter */ 275 if (kset->uevent_ops && kset->uevent_ops->filter) 276 if (!kset->uevent_ops->filter(kset, &dev->kobj)) 277 goto out; 278 279 data = (char *)get_zeroed_page(GFP_KERNEL); 280 if (!data) 281 return -ENOMEM; 282 283 /* let the kset specific function add its keys */ 284 pos = data; 285 retval = kset->uevent_ops->uevent(kset, &dev->kobj, 286 envp, ARRAY_SIZE(envp), 287 pos, PAGE_SIZE); 288 if (retval) 289 goto out; 290 291 /* copy keys to file */ 292 for (i = 0; envp[i]; i++) { 293 pos = &buf[count]; 294 count += sprintf(pos, "%s\n", envp[i]); 295 } 296 out: 297 free_page((unsigned long)data); 298 return count; 299 } 300 301 static ssize_t store_uevent(struct device *dev, struct device_attribute *attr, 302 const char *buf, size_t count) 303 { 304 if (memcmp(buf, "add", 3) != 0) 305 dev_err(dev, "uevent: unsupported action-string; this will " 306 "be ignored in a future kernel version"); 307 kobject_uevent(&dev->kobj, KOBJ_ADD); 308 return count; 309 } 310 311 static int device_add_attributes(struct device *dev, 312 struct device_attribute *attrs) 313 { 314 int error = 0; 315 int i; 316 317 if (attrs) { 318 for (i = 0; attr_name(attrs[i]); i++) { 319 error = device_create_file(dev, &attrs[i]); 320 if (error) 321 break; 322 } 323 if (error) 324 while (--i >= 0) 325 device_remove_file(dev, &attrs[i]); 326 } 327 return error; 328 } 329 330 static void device_remove_attributes(struct device *dev, 331 struct device_attribute *attrs) 332 { 333 int i; 334 335 if (attrs) 336 for (i = 0; attr_name(attrs[i]); i++) 337 device_remove_file(dev, &attrs[i]); 338 } 339 340 static int device_add_groups(struct device *dev, 341 struct attribute_group **groups) 342 { 343 int error = 0; 344 int i; 345 346 if (groups) { 347 for (i = 0; groups[i]; i++) { 348 error = sysfs_create_group(&dev->kobj, groups[i]); 349 if (error) { 350 while (--i >= 0) 351 sysfs_remove_group(&dev->kobj, groups[i]); 352 break; 353 } 354 } 355 } 356 return error; 357 } 358 359 static void device_remove_groups(struct device *dev, 360 struct attribute_group **groups) 361 { 362 int i; 363 364 if (groups) 365 for (i = 0; groups[i]; i++) 366 sysfs_remove_group(&dev->kobj, groups[i]); 367 } 368 369 static int device_add_attrs(struct device *dev) 370 { 371 struct class *class = dev->class; 372 struct device_type *type = dev->type; 373 int error; 374 375 if (class) { 376 error = device_add_attributes(dev, class->dev_attrs); 377 if (error) 378 return error; 379 } 380 381 if (type) { 382 error = device_add_groups(dev, type->groups); 383 if (error) 384 goto err_remove_class_attrs; 385 } 386 387 error = device_add_groups(dev, dev->groups); 388 if (error) 389 goto err_remove_type_groups; 390 391 return 0; 392 393 err_remove_type_groups: 394 if (type) 395 device_remove_groups(dev, type->groups); 396 err_remove_class_attrs: 397 if (class) 398 device_remove_attributes(dev, class->dev_attrs); 399 400 return error; 401 } 402 403 static void device_remove_attrs(struct device *dev) 404 { 405 struct class *class = dev->class; 406 struct device_type *type = dev->type; 407 408 device_remove_groups(dev, dev->groups); 409 410 if (type) 411 device_remove_groups(dev, type->groups); 412 413 if (class) 414 device_remove_attributes(dev, class->dev_attrs); 415 } 416 417 418 static ssize_t show_dev(struct device *dev, struct device_attribute *attr, 419 char *buf) 420 { 421 return print_dev_t(buf, dev->devt); 422 } 423 424 /* 425 * devices_subsys - structure to be registered with kobject core. 426 */ 427 428 decl_subsys(devices, &ktype_device, &device_uevent_ops); 429 430 431 /** 432 * device_create_file - create sysfs attribute file for device. 433 * @dev: device. 434 * @attr: device attribute descriptor. 435 */ 436 437 int device_create_file(struct device * dev, struct device_attribute * attr) 438 { 439 int error = 0; 440 if (get_device(dev)) { 441 error = sysfs_create_file(&dev->kobj, &attr->attr); 442 put_device(dev); 443 } 444 return error; 445 } 446 447 /** 448 * device_remove_file - remove sysfs attribute file. 449 * @dev: device. 450 * @attr: device attribute descriptor. 451 */ 452 453 void device_remove_file(struct device * dev, struct device_attribute * attr) 454 { 455 if (get_device(dev)) { 456 sysfs_remove_file(&dev->kobj, &attr->attr); 457 put_device(dev); 458 } 459 } 460 461 /** 462 * device_create_bin_file - create sysfs binary attribute file for device. 463 * @dev: device. 464 * @attr: device binary attribute descriptor. 465 */ 466 int device_create_bin_file(struct device *dev, struct bin_attribute *attr) 467 { 468 int error = -EINVAL; 469 if (dev) 470 error = sysfs_create_bin_file(&dev->kobj, attr); 471 return error; 472 } 473 EXPORT_SYMBOL_GPL(device_create_bin_file); 474 475 /** 476 * device_remove_bin_file - remove sysfs binary attribute file 477 * @dev: device. 478 * @attr: device binary attribute descriptor. 479 */ 480 void device_remove_bin_file(struct device *dev, struct bin_attribute *attr) 481 { 482 if (dev) 483 sysfs_remove_bin_file(&dev->kobj, attr); 484 } 485 EXPORT_SYMBOL_GPL(device_remove_bin_file); 486 487 /** 488 * device_schedule_callback_owner - helper to schedule a callback for a device 489 * @dev: device. 490 * @func: callback function to invoke later. 491 * @owner: module owning the callback routine 492 * 493 * Attribute methods must not unregister themselves or their parent device 494 * (which would amount to the same thing). Attempts to do so will deadlock, 495 * since unregistration is mutually exclusive with driver callbacks. 496 * 497 * Instead methods can call this routine, which will attempt to allocate 498 * and schedule a workqueue request to call back @func with @dev as its 499 * argument in the workqueue's process context. @dev will be pinned until 500 * @func returns. 501 * 502 * This routine is usually called via the inline device_schedule_callback(), 503 * which automatically sets @owner to THIS_MODULE. 504 * 505 * Returns 0 if the request was submitted, -ENOMEM if storage could not 506 * be allocated, -ENODEV if a reference to @owner isn't available. 507 * 508 * NOTE: This routine won't work if CONFIG_SYSFS isn't set! It uses an 509 * underlying sysfs routine (since it is intended for use by attribute 510 * methods), and if sysfs isn't available you'll get nothing but -ENOSYS. 511 */ 512 int device_schedule_callback_owner(struct device *dev, 513 void (*func)(struct device *), struct module *owner) 514 { 515 return sysfs_schedule_callback(&dev->kobj, 516 (void (*)(void *)) func, dev, owner); 517 } 518 EXPORT_SYMBOL_GPL(device_schedule_callback_owner); 519 520 static void klist_children_get(struct klist_node *n) 521 { 522 struct device *dev = container_of(n, struct device, knode_parent); 523 524 get_device(dev); 525 } 526 527 static void klist_children_put(struct klist_node *n) 528 { 529 struct device *dev = container_of(n, struct device, knode_parent); 530 531 put_device(dev); 532 } 533 534 535 /** 536 * device_initialize - init device structure. 537 * @dev: device. 538 * 539 * This prepares the device for use by other layers, 540 * including adding it to the device hierarchy. 541 * It is the first half of device_register(), if called by 542 * that, though it can also be called separately, so one 543 * may use @dev's fields (e.g. the refcount). 544 */ 545 546 void device_initialize(struct device *dev) 547 { 548 kobj_set_kset_s(dev, devices_subsys); 549 kobject_init(&dev->kobj); 550 klist_init(&dev->klist_children, klist_children_get, 551 klist_children_put); 552 INIT_LIST_HEAD(&dev->dma_pools); 553 INIT_LIST_HEAD(&dev->node); 554 init_MUTEX(&dev->sem); 555 spin_lock_init(&dev->devres_lock); 556 INIT_LIST_HEAD(&dev->devres_head); 557 device_init_wakeup(dev, 0); 558 set_dev_node(dev, -1); 559 } 560 561 #ifdef CONFIG_SYSFS_DEPRECATED 562 static struct kobject * get_device_parent(struct device *dev, 563 struct device *parent) 564 { 565 /* Set the parent to the class, not the parent device */ 566 /* this keeps sysfs from having a symlink to make old udevs happy */ 567 if (dev->class) 568 return &dev->class->subsys.kobj; 569 else if (parent) 570 return &parent->kobj; 571 572 return NULL; 573 } 574 #else 575 static struct kobject *virtual_device_parent(struct device *dev) 576 { 577 static struct kobject *virtual_dir = NULL; 578 579 if (!virtual_dir) 580 virtual_dir = kobject_add_dir(&devices_subsys.kobj, "virtual"); 581 582 return virtual_dir; 583 } 584 585 static struct kobject * get_device_parent(struct device *dev, 586 struct device *parent) 587 { 588 if (dev->class) { 589 struct kobject *kobj = NULL; 590 struct kobject *parent_kobj; 591 struct kobject *k; 592 593 /* 594 * If we have no parent, we live in "virtual". 595 * Class-devices with a bus-device as parent, live 596 * in a class-directory to prevent namespace collisions. 597 */ 598 if (parent == NULL) 599 parent_kobj = virtual_device_parent(dev); 600 else if (parent->class) 601 return &parent->kobj; 602 else 603 parent_kobj = &parent->kobj; 604 605 /* find our class-directory at the parent and reference it */ 606 spin_lock(&dev->class->class_dirs.list_lock); 607 list_for_each_entry(k, &dev->class->class_dirs.list, entry) 608 if (k->parent == parent_kobj) { 609 kobj = kobject_get(k); 610 break; 611 } 612 spin_unlock(&dev->class->class_dirs.list_lock); 613 if (kobj) 614 return kobj; 615 616 /* or create a new class-directory at the parent device */ 617 return kobject_kset_add_dir(&dev->class->class_dirs, 618 parent_kobj, dev->class->name); 619 } 620 621 if (parent) 622 return &parent->kobj; 623 return NULL; 624 } 625 #endif 626 627 static int setup_parent(struct device *dev, struct device *parent) 628 { 629 struct kobject *kobj; 630 kobj = get_device_parent(dev, parent); 631 if (IS_ERR(kobj)) 632 return PTR_ERR(kobj); 633 if (kobj) 634 dev->kobj.parent = kobj; 635 return 0; 636 } 637 638 /** 639 * device_add - add device to device hierarchy. 640 * @dev: device. 641 * 642 * This is part 2 of device_register(), though may be called 643 * separately _iff_ device_initialize() has been called separately. 644 * 645 * This adds it to the kobject hierarchy via kobject_add(), adds it 646 * to the global and sibling lists for the device, then 647 * adds it to the other relevant subsystems of the driver model. 648 */ 649 int device_add(struct device *dev) 650 { 651 struct device *parent = NULL; 652 char *class_name = NULL; 653 struct class_interface *class_intf; 654 int error = -EINVAL; 655 656 dev = get_device(dev); 657 if (!dev || !strlen(dev->bus_id)) 658 goto Error; 659 660 pr_debug("DEV: registering device: ID = '%s'\n", dev->bus_id); 661 662 parent = get_device(dev->parent); 663 error = setup_parent(dev, parent); 664 if (error) 665 goto Error; 666 667 /* first, register with generic layer. */ 668 kobject_set_name(&dev->kobj, "%s", dev->bus_id); 669 error = kobject_add(&dev->kobj); 670 if (error) 671 goto Error; 672 673 /* notify platform of device entry */ 674 if (platform_notify) 675 platform_notify(dev); 676 677 /* notify clients of device entry (new way) */ 678 if (dev->bus) 679 blocking_notifier_call_chain(&dev->bus->bus_notifier, 680 BUS_NOTIFY_ADD_DEVICE, dev); 681 682 dev->uevent_attr.attr.name = "uevent"; 683 dev->uevent_attr.attr.mode = S_IRUGO | S_IWUSR; 684 if (dev->driver) 685 dev->uevent_attr.attr.owner = dev->driver->owner; 686 dev->uevent_attr.store = store_uevent; 687 dev->uevent_attr.show = show_uevent; 688 error = device_create_file(dev, &dev->uevent_attr); 689 if (error) 690 goto attrError; 691 692 if (MAJOR(dev->devt)) { 693 struct device_attribute *attr; 694 attr = kzalloc(sizeof(*attr), GFP_KERNEL); 695 if (!attr) { 696 error = -ENOMEM; 697 goto ueventattrError; 698 } 699 attr->attr.name = "dev"; 700 attr->attr.mode = S_IRUGO; 701 if (dev->driver) 702 attr->attr.owner = dev->driver->owner; 703 attr->show = show_dev; 704 error = device_create_file(dev, attr); 705 if (error) { 706 kfree(attr); 707 goto ueventattrError; 708 } 709 710 dev->devt_attr = attr; 711 } 712 713 if (dev->class) { 714 sysfs_create_link(&dev->kobj, &dev->class->subsys.kobj, 715 "subsystem"); 716 /* If this is not a "fake" compatible device, then create the 717 * symlink from the class to the device. */ 718 if (dev->kobj.parent != &dev->class->subsys.kobj) 719 sysfs_create_link(&dev->class->subsys.kobj, 720 &dev->kobj, dev->bus_id); 721 if (parent) { 722 sysfs_create_link(&dev->kobj, &dev->parent->kobj, 723 "device"); 724 #ifdef CONFIG_SYSFS_DEPRECATED 725 class_name = make_class_name(dev->class->name, 726 &dev->kobj); 727 if (class_name) 728 sysfs_create_link(&dev->parent->kobj, 729 &dev->kobj, class_name); 730 #endif 731 } 732 } 733 734 if ((error = device_add_attrs(dev))) 735 goto AttrsError; 736 if ((error = device_pm_add(dev))) 737 goto PMError; 738 if ((error = bus_add_device(dev))) 739 goto BusError; 740 kobject_uevent(&dev->kobj, KOBJ_ADD); 741 bus_attach_device(dev); 742 if (parent) 743 klist_add_tail(&dev->knode_parent, &parent->klist_children); 744 745 if (dev->class) { 746 down(&dev->class->sem); 747 /* tie the class to the device */ 748 list_add_tail(&dev->node, &dev->class->devices); 749 750 /* notify any interfaces that the device is here */ 751 list_for_each_entry(class_intf, &dev->class->interfaces, node) 752 if (class_intf->add_dev) 753 class_intf->add_dev(dev, class_intf); 754 up(&dev->class->sem); 755 } 756 Done: 757 kfree(class_name); 758 put_device(dev); 759 return error; 760 BusError: 761 device_pm_remove(dev); 762 PMError: 763 if (dev->bus) 764 blocking_notifier_call_chain(&dev->bus->bus_notifier, 765 BUS_NOTIFY_DEL_DEVICE, dev); 766 device_remove_attrs(dev); 767 AttrsError: 768 if (dev->devt_attr) { 769 device_remove_file(dev, dev->devt_attr); 770 kfree(dev->devt_attr); 771 } 772 773 if (dev->class) { 774 sysfs_remove_link(&dev->kobj, "subsystem"); 775 /* If this is not a "fake" compatible device, remove the 776 * symlink from the class to the device. */ 777 if (dev->kobj.parent != &dev->class->subsys.kobj) 778 sysfs_remove_link(&dev->class->subsys.kobj, 779 dev->bus_id); 780 if (parent) { 781 #ifdef CONFIG_SYSFS_DEPRECATED 782 char *class_name = make_class_name(dev->class->name, 783 &dev->kobj); 784 if (class_name) 785 sysfs_remove_link(&dev->parent->kobj, 786 class_name); 787 kfree(class_name); 788 #endif 789 sysfs_remove_link(&dev->kobj, "device"); 790 } 791 } 792 ueventattrError: 793 device_remove_file(dev, &dev->uevent_attr); 794 attrError: 795 kobject_uevent(&dev->kobj, KOBJ_REMOVE); 796 kobject_del(&dev->kobj); 797 Error: 798 if (parent) 799 put_device(parent); 800 goto Done; 801 } 802 803 804 /** 805 * device_register - register a device with the system. 806 * @dev: pointer to the device structure 807 * 808 * This happens in two clean steps - initialize the device 809 * and add it to the system. The two steps can be called 810 * separately, but this is the easiest and most common. 811 * I.e. you should only call the two helpers separately if 812 * have a clearly defined need to use and refcount the device 813 * before it is added to the hierarchy. 814 */ 815 816 int device_register(struct device *dev) 817 { 818 device_initialize(dev); 819 return device_add(dev); 820 } 821 822 823 /** 824 * get_device - increment reference count for device. 825 * @dev: device. 826 * 827 * This simply forwards the call to kobject_get(), though 828 * we do take care to provide for the case that we get a NULL 829 * pointer passed in. 830 */ 831 832 struct device * get_device(struct device * dev) 833 { 834 return dev ? to_dev(kobject_get(&dev->kobj)) : NULL; 835 } 836 837 838 /** 839 * put_device - decrement reference count. 840 * @dev: device in question. 841 */ 842 void put_device(struct device * dev) 843 { 844 if (dev) 845 kobject_put(&dev->kobj); 846 } 847 848 849 /** 850 * device_del - delete device from system. 851 * @dev: device. 852 * 853 * This is the first part of the device unregistration 854 * sequence. This removes the device from the lists we control 855 * from here, has it removed from the other driver model 856 * subsystems it was added to in device_add(), and removes it 857 * from the kobject hierarchy. 858 * 859 * NOTE: this should be called manually _iff_ device_add() was 860 * also called manually. 861 */ 862 863 void device_del(struct device * dev) 864 { 865 struct device * parent = dev->parent; 866 struct class_interface *class_intf; 867 868 if (parent) 869 klist_del(&dev->knode_parent); 870 if (dev->devt_attr) { 871 device_remove_file(dev, dev->devt_attr); 872 kfree(dev->devt_attr); 873 } 874 if (dev->class) { 875 sysfs_remove_link(&dev->kobj, "subsystem"); 876 /* If this is not a "fake" compatible device, remove the 877 * symlink from the class to the device. */ 878 if (dev->kobj.parent != &dev->class->subsys.kobj) 879 sysfs_remove_link(&dev->class->subsys.kobj, 880 dev->bus_id); 881 if (parent) { 882 #ifdef CONFIG_SYSFS_DEPRECATED 883 char *class_name = make_class_name(dev->class->name, 884 &dev->kobj); 885 if (class_name) 886 sysfs_remove_link(&dev->parent->kobj, 887 class_name); 888 kfree(class_name); 889 #endif 890 sysfs_remove_link(&dev->kobj, "device"); 891 } 892 893 down(&dev->class->sem); 894 /* notify any interfaces that the device is now gone */ 895 list_for_each_entry(class_intf, &dev->class->interfaces, node) 896 if (class_intf->remove_dev) 897 class_intf->remove_dev(dev, class_intf); 898 /* remove the device from the class list */ 899 list_del_init(&dev->node); 900 up(&dev->class->sem); 901 902 /* If we live in a parent class-directory, unreference it */ 903 if (dev->kobj.parent->kset == &dev->class->class_dirs) { 904 struct device *d; 905 int other = 0; 906 907 /* 908 * if we are the last child of our class, delete 909 * our class-directory at this parent 910 */ 911 down(&dev->class->sem); 912 list_for_each_entry(d, &dev->class->devices, node) { 913 if (d == dev) 914 continue; 915 if (d->kobj.parent == dev->kobj.parent) { 916 other = 1; 917 break; 918 } 919 } 920 if (!other) 921 kobject_del(dev->kobj.parent); 922 923 kobject_put(dev->kobj.parent); 924 up(&dev->class->sem); 925 } 926 } 927 device_remove_file(dev, &dev->uevent_attr); 928 device_remove_attrs(dev); 929 bus_remove_device(dev); 930 931 /* 932 * Some platform devices are driven without driver attached 933 * and managed resources may have been acquired. Make sure 934 * all resources are released. 935 */ 936 devres_release_all(dev); 937 938 /* Notify the platform of the removal, in case they 939 * need to do anything... 940 */ 941 if (platform_notify_remove) 942 platform_notify_remove(dev); 943 if (dev->bus) 944 blocking_notifier_call_chain(&dev->bus->bus_notifier, 945 BUS_NOTIFY_DEL_DEVICE, dev); 946 device_pm_remove(dev); 947 kobject_uevent(&dev->kobj, KOBJ_REMOVE); 948 kobject_del(&dev->kobj); 949 if (parent) 950 put_device(parent); 951 } 952 953 /** 954 * device_unregister - unregister device from system. 955 * @dev: device going away. 956 * 957 * We do this in two parts, like we do device_register(). First, 958 * we remove it from all the subsystems with device_del(), then 959 * we decrement the reference count via put_device(). If that 960 * is the final reference count, the device will be cleaned up 961 * via device_release() above. Otherwise, the structure will 962 * stick around until the final reference to the device is dropped. 963 */ 964 void device_unregister(struct device * dev) 965 { 966 pr_debug("DEV: Unregistering device. ID = '%s'\n", dev->bus_id); 967 device_del(dev); 968 put_device(dev); 969 } 970 971 972 static struct device * next_device(struct klist_iter * i) 973 { 974 struct klist_node * n = klist_next(i); 975 return n ? container_of(n, struct device, knode_parent) : NULL; 976 } 977 978 /** 979 * device_for_each_child - device child iterator. 980 * @parent: parent struct device. 981 * @data: data for the callback. 982 * @fn: function to be called for each device. 983 * 984 * Iterate over @parent's child devices, and call @fn for each, 985 * passing it @data. 986 * 987 * We check the return of @fn each time. If it returns anything 988 * other than 0, we break out and return that value. 989 */ 990 int device_for_each_child(struct device * parent, void * data, 991 int (*fn)(struct device *, void *)) 992 { 993 struct klist_iter i; 994 struct device * child; 995 int error = 0; 996 997 klist_iter_init(&parent->klist_children, &i); 998 while ((child = next_device(&i)) && !error) 999 error = fn(child, data); 1000 klist_iter_exit(&i); 1001 return error; 1002 } 1003 1004 /** 1005 * device_find_child - device iterator for locating a particular device. 1006 * @parent: parent struct device 1007 * @data: Data to pass to match function 1008 * @match: Callback function to check device 1009 * 1010 * This is similar to the device_for_each_child() function above, but it 1011 * returns a reference to a device that is 'found' for later use, as 1012 * determined by the @match callback. 1013 * 1014 * The callback should return 0 if the device doesn't match and non-zero 1015 * if it does. If the callback returns non-zero and a reference to the 1016 * current device can be obtained, this function will return to the caller 1017 * and not iterate over any more devices. 1018 */ 1019 struct device * device_find_child(struct device *parent, void *data, 1020 int (*match)(struct device *, void *)) 1021 { 1022 struct klist_iter i; 1023 struct device *child; 1024 1025 if (!parent) 1026 return NULL; 1027 1028 klist_iter_init(&parent->klist_children, &i); 1029 while ((child = next_device(&i))) 1030 if (match(child, data) && get_device(child)) 1031 break; 1032 klist_iter_exit(&i); 1033 return child; 1034 } 1035 1036 int __init devices_init(void) 1037 { 1038 return subsystem_register(&devices_subsys); 1039 } 1040 1041 EXPORT_SYMBOL_GPL(device_for_each_child); 1042 EXPORT_SYMBOL_GPL(device_find_child); 1043 1044 EXPORT_SYMBOL_GPL(device_initialize); 1045 EXPORT_SYMBOL_GPL(device_add); 1046 EXPORT_SYMBOL_GPL(device_register); 1047 1048 EXPORT_SYMBOL_GPL(device_del); 1049 EXPORT_SYMBOL_GPL(device_unregister); 1050 EXPORT_SYMBOL_GPL(get_device); 1051 EXPORT_SYMBOL_GPL(put_device); 1052 1053 EXPORT_SYMBOL_GPL(device_create_file); 1054 EXPORT_SYMBOL_GPL(device_remove_file); 1055 1056 1057 static void device_create_release(struct device *dev) 1058 { 1059 pr_debug("%s called for %s\n", __FUNCTION__, dev->bus_id); 1060 kfree(dev); 1061 } 1062 1063 /** 1064 * device_create - creates a device and registers it with sysfs 1065 * @class: pointer to the struct class that this device should be registered to 1066 * @parent: pointer to the parent struct device of this new device, if any 1067 * @devt: the dev_t for the char device to be added 1068 * @fmt: string for the device's name 1069 * 1070 * This function can be used by char device classes. A struct device 1071 * will be created in sysfs, registered to the specified class. 1072 * 1073 * A "dev" file will be created, showing the dev_t for the device, if 1074 * the dev_t is not 0,0. 1075 * If a pointer to a parent struct device is passed in, the newly created 1076 * struct device will be a child of that device in sysfs. 1077 * The pointer to the struct device will be returned from the call. 1078 * Any further sysfs files that might be required can be created using this 1079 * pointer. 1080 * 1081 * Note: the struct class passed to this function must have previously 1082 * been created with a call to class_create(). 1083 */ 1084 struct device *device_create(struct class *class, struct device *parent, 1085 dev_t devt, const char *fmt, ...) 1086 { 1087 va_list args; 1088 struct device *dev = NULL; 1089 int retval = -ENODEV; 1090 1091 if (class == NULL || IS_ERR(class)) 1092 goto error; 1093 1094 dev = kzalloc(sizeof(*dev), GFP_KERNEL); 1095 if (!dev) { 1096 retval = -ENOMEM; 1097 goto error; 1098 } 1099 1100 dev->devt = devt; 1101 dev->class = class; 1102 dev->parent = parent; 1103 dev->release = device_create_release; 1104 1105 va_start(args, fmt); 1106 vsnprintf(dev->bus_id, BUS_ID_SIZE, fmt, args); 1107 va_end(args); 1108 retval = device_register(dev); 1109 if (retval) 1110 goto error; 1111 1112 return dev; 1113 1114 error: 1115 kfree(dev); 1116 return ERR_PTR(retval); 1117 } 1118 EXPORT_SYMBOL_GPL(device_create); 1119 1120 /** 1121 * device_destroy - removes a device that was created with device_create() 1122 * @class: pointer to the struct class that this device was registered with 1123 * @devt: the dev_t of the device that was previously registered 1124 * 1125 * This call unregisters and cleans up a device that was created with a 1126 * call to device_create(). 1127 */ 1128 void device_destroy(struct class *class, dev_t devt) 1129 { 1130 struct device *dev = NULL; 1131 struct device *dev_tmp; 1132 1133 down(&class->sem); 1134 list_for_each_entry(dev_tmp, &class->devices, node) { 1135 if (dev_tmp->devt == devt) { 1136 dev = dev_tmp; 1137 break; 1138 } 1139 } 1140 up(&class->sem); 1141 1142 if (dev) 1143 device_unregister(dev); 1144 } 1145 EXPORT_SYMBOL_GPL(device_destroy); 1146 1147 /** 1148 * device_rename - renames a device 1149 * @dev: the pointer to the struct device to be renamed 1150 * @new_name: the new name of the device 1151 */ 1152 int device_rename(struct device *dev, char *new_name) 1153 { 1154 char *old_class_name = NULL; 1155 char *new_class_name = NULL; 1156 char *old_symlink_name = NULL; 1157 int error; 1158 1159 dev = get_device(dev); 1160 if (!dev) 1161 return -EINVAL; 1162 1163 pr_debug("DEVICE: renaming '%s' to '%s'\n", dev->bus_id, new_name); 1164 1165 #ifdef CONFIG_SYSFS_DEPRECATED 1166 if ((dev->class) && (dev->parent)) 1167 old_class_name = make_class_name(dev->class->name, &dev->kobj); 1168 #endif 1169 1170 if (dev->class) { 1171 old_symlink_name = kmalloc(BUS_ID_SIZE, GFP_KERNEL); 1172 if (!old_symlink_name) { 1173 error = -ENOMEM; 1174 goto out_free_old_class; 1175 } 1176 strlcpy(old_symlink_name, dev->bus_id, BUS_ID_SIZE); 1177 } 1178 1179 strlcpy(dev->bus_id, new_name, BUS_ID_SIZE); 1180 1181 error = kobject_rename(&dev->kobj, new_name); 1182 1183 #ifdef CONFIG_SYSFS_DEPRECATED 1184 if (old_class_name) { 1185 new_class_name = make_class_name(dev->class->name, &dev->kobj); 1186 if (new_class_name) { 1187 sysfs_create_link(&dev->parent->kobj, &dev->kobj, 1188 new_class_name); 1189 sysfs_remove_link(&dev->parent->kobj, old_class_name); 1190 } 1191 } 1192 #endif 1193 1194 if (dev->class) { 1195 sysfs_remove_link(&dev->class->subsys.kobj, 1196 old_symlink_name); 1197 sysfs_create_link(&dev->class->subsys.kobj, &dev->kobj, 1198 dev->bus_id); 1199 } 1200 put_device(dev); 1201 1202 kfree(new_class_name); 1203 kfree(old_symlink_name); 1204 out_free_old_class: 1205 kfree(old_class_name); 1206 1207 return error; 1208 } 1209 EXPORT_SYMBOL_GPL(device_rename); 1210 1211 static int device_move_class_links(struct device *dev, 1212 struct device *old_parent, 1213 struct device *new_parent) 1214 { 1215 int error = 0; 1216 #ifdef CONFIG_SYSFS_DEPRECATED 1217 char *class_name; 1218 1219 class_name = make_class_name(dev->class->name, &dev->kobj); 1220 if (!class_name) { 1221 error = -ENOMEM; 1222 goto out; 1223 } 1224 if (old_parent) { 1225 sysfs_remove_link(&dev->kobj, "device"); 1226 sysfs_remove_link(&old_parent->kobj, class_name); 1227 } 1228 if (new_parent) { 1229 error = sysfs_create_link(&dev->kobj, &new_parent->kobj, 1230 "device"); 1231 if (error) 1232 goto out; 1233 error = sysfs_create_link(&new_parent->kobj, &dev->kobj, 1234 class_name); 1235 if (error) 1236 sysfs_remove_link(&dev->kobj, "device"); 1237 } 1238 else 1239 error = 0; 1240 out: 1241 kfree(class_name); 1242 return error; 1243 #else 1244 if (old_parent) 1245 sysfs_remove_link(&dev->kobj, "device"); 1246 if (new_parent) 1247 error = sysfs_create_link(&dev->kobj, &new_parent->kobj, 1248 "device"); 1249 return error; 1250 #endif 1251 } 1252 1253 /** 1254 * device_move - moves a device to a new parent 1255 * @dev: the pointer to the struct device to be moved 1256 * @new_parent: the new parent of the device (can by NULL) 1257 */ 1258 int device_move(struct device *dev, struct device *new_parent) 1259 { 1260 int error; 1261 struct device *old_parent; 1262 struct kobject *new_parent_kobj; 1263 1264 dev = get_device(dev); 1265 if (!dev) 1266 return -EINVAL; 1267 1268 new_parent = get_device(new_parent); 1269 new_parent_kobj = get_device_parent (dev, new_parent); 1270 if (IS_ERR(new_parent_kobj)) { 1271 error = PTR_ERR(new_parent_kobj); 1272 put_device(new_parent); 1273 goto out; 1274 } 1275 pr_debug("DEVICE: moving '%s' to '%s'\n", dev->bus_id, 1276 new_parent ? new_parent->bus_id : "<NULL>"); 1277 error = kobject_move(&dev->kobj, new_parent_kobj); 1278 if (error) { 1279 put_device(new_parent); 1280 goto out; 1281 } 1282 old_parent = dev->parent; 1283 dev->parent = new_parent; 1284 if (old_parent) 1285 klist_remove(&dev->knode_parent); 1286 if (new_parent) 1287 klist_add_tail(&dev->knode_parent, &new_parent->klist_children); 1288 if (!dev->class) 1289 goto out_put; 1290 error = device_move_class_links(dev, old_parent, new_parent); 1291 if (error) { 1292 /* We ignore errors on cleanup since we're hosed anyway... */ 1293 device_move_class_links(dev, new_parent, old_parent); 1294 if (!kobject_move(&dev->kobj, &old_parent->kobj)) { 1295 if (new_parent) 1296 klist_remove(&dev->knode_parent); 1297 if (old_parent) 1298 klist_add_tail(&dev->knode_parent, 1299 &old_parent->klist_children); 1300 } 1301 put_device(new_parent); 1302 goto out; 1303 } 1304 out_put: 1305 put_device(old_parent); 1306 out: 1307 put_device(dev); 1308 return error; 1309 } 1310 1311 EXPORT_SYMBOL_GPL(device_move); 1312