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 27int (*platform_notify)(struct device * dev) = NULL; 28int (*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 */ 43const 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} 49EXPORT_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 54static ssize_t 55dev_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 66static ssize_t 67dev_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 79static 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 */ 93static 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 111static struct kobj_type ktype_device = { 112 .release = device_release, 113 .sysfs_ops = &dev_sysfs_ops, 114}; 115 116 117static 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 133static 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 144static 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 if (path) { 184 add_uevent_var(envp, num_envp, &i, 185 buffer, buffer_size, &length, 186 "PHYSDEVPATH=%s", path); 187 kfree(path); 188 } 189 190 add_uevent_var(envp, num_envp, &i, 191 buffer, buffer_size, &length, 192 "PHYSDEVBUS=%s", parent->bus->name); 193 194 if (parent->driver) 195 add_uevent_var(envp, num_envp, &i, 196 buffer, buffer_size, &length, 197 "PHYSDEVDRIVER=%s", parent->driver->name); 198 } 199 } else if (dev->bus) { 200 add_uevent_var(envp, num_envp, &i, 201 buffer, buffer_size, &length, 202 "PHYSDEVBUS=%s", dev->bus->name); 203 204 if (dev->driver) 205 add_uevent_var(envp, num_envp, &i, 206 buffer, buffer_size, &length, 207 "PHYSDEVDRIVER=%s", dev->driver->name); 208 } 209#endif 210 211 /* terminate, set to next free slot, shrink available space */ 212 envp[i] = NULL; 213 envp = &envp[i]; 214 num_envp -= i; 215 buffer = &buffer[length]; 216 buffer_size -= length; 217 218 if (dev->bus && dev->bus->uevent) { 219 /* have the bus specific function add its stuff */ 220 retval = dev->bus->uevent(dev, envp, num_envp, buffer, buffer_size); 221 if (retval) 222 pr_debug ("%s: bus uevent() returned %d\n", 223 __FUNCTION__, retval); 224 } 225 226 if (dev->class && dev->class->dev_uevent) { 227 /* have the class specific function add its stuff */ 228 retval = dev->class->dev_uevent(dev, envp, num_envp, buffer, buffer_size); 229 if (retval) 230 pr_debug("%s: class uevent() returned %d\n", 231 __FUNCTION__, retval); 232 } 233 234 if (dev->type && dev->type->uevent) { 235 /* have the device type specific fuction add its stuff */ 236 retval = dev->type->uevent(dev, envp, num_envp, buffer, buffer_size); 237 if (retval) 238 pr_debug("%s: dev_type uevent() returned %d\n", 239 __FUNCTION__, retval); 240 } 241 242 return retval; 243} 244 245static struct kset_uevent_ops device_uevent_ops = { 246 .filter = dev_uevent_filter, 247 .name = dev_uevent_name, 248 .uevent = dev_uevent, 249}; 250 251static ssize_t show_uevent(struct device *dev, struct device_attribute *attr, 252 char *buf) 253{ 254 struct kobject *top_kobj; 255 struct kset *kset; 256 char *envp[32]; 257 char *data = NULL; 258 char *pos; 259 int i; 260 size_t count = 0; 261 int retval; 262 263 /* search the kset, the device belongs to */ 264 top_kobj = &dev->kobj; 265 if (!top_kobj->kset && top_kobj->parent) { 266 do { 267 top_kobj = top_kobj->parent; 268 } while (!top_kobj->kset && top_kobj->parent); 269 } 270 if (!top_kobj->kset) 271 goto out; 272 kset = top_kobj->kset; 273 if (!kset->uevent_ops || !kset->uevent_ops->uevent) 274 goto out; 275 276 /* respect filter */ 277 if (kset->uevent_ops && kset->uevent_ops->filter) 278 if (!kset->uevent_ops->filter(kset, &dev->kobj)) 279 goto out; 280 281 data = (char *)get_zeroed_page(GFP_KERNEL); 282 if (!data) 283 return -ENOMEM; 284 285 /* let the kset specific function add its keys */ 286 pos = data; 287 retval = kset->uevent_ops->uevent(kset, &dev->kobj, 288 envp, ARRAY_SIZE(envp), 289 pos, PAGE_SIZE); 290 if (retval) 291 goto out; 292 293 /* copy keys to file */ 294 for (i = 0; envp[i]; i++) { 295 pos = &buf[count]; 296 count += sprintf(pos, "%s\n", envp[i]); 297 } 298out: 299 free_page((unsigned long)data); 300 return count; 301} 302 303static ssize_t store_uevent(struct device *dev, struct device_attribute *attr, 304 const char *buf, size_t count) 305{ 306 if (memcmp(buf, "add", 3) != 0) 307 dev_err(dev, "uevent: unsupported action-string; this will " 308 "be ignored in a future kernel version"); 309 kobject_uevent(&dev->kobj, KOBJ_ADD); 310 return count; 311} 312 313static int device_add_attributes(struct device *dev, 314 struct device_attribute *attrs) 315{ 316 int error = 0; 317 int i; 318 319 if (attrs) { 320 for (i = 0; attr_name(attrs[i]); i++) { 321 error = device_create_file(dev, &attrs[i]); 322 if (error) 323 break; 324 } 325 if (error) 326 while (--i >= 0) 327 device_remove_file(dev, &attrs[i]); 328 } 329 return error; 330} 331 332static void device_remove_attributes(struct device *dev, 333 struct device_attribute *attrs) 334{ 335 int i; 336 337 if (attrs) 338 for (i = 0; attr_name(attrs[i]); i++) 339 device_remove_file(dev, &attrs[i]); 340} 341 342static int device_add_groups(struct device *dev, 343 struct attribute_group **groups) 344{ 345 int error = 0; 346 int i; 347 348 if (groups) { 349 for (i = 0; groups[i]; i++) { 350 error = sysfs_create_group(&dev->kobj, groups[i]); 351 if (error) { 352 while (--i >= 0) 353 sysfs_remove_group(&dev->kobj, groups[i]); 354 break; 355 } 356 } 357 } 358 return error; 359} 360 361static void device_remove_groups(struct device *dev, 362 struct attribute_group **groups) 363{ 364 int i; 365 366 if (groups) 367 for (i = 0; groups[i]; i++) 368 sysfs_remove_group(&dev->kobj, groups[i]); 369} 370 371static int device_add_attrs(struct device *dev) 372{ 373 struct class *class = dev->class; 374 struct device_type *type = dev->type; 375 int error; 376 377 if (class) { 378 error = device_add_attributes(dev, class->dev_attrs); 379 if (error) 380 return error; 381 } 382 383 if (type) { 384 error = device_add_groups(dev, type->groups); 385 if (error) 386 goto err_remove_class_attrs; 387 } 388 389 error = device_add_groups(dev, dev->groups); 390 if (error) 391 goto err_remove_type_groups; 392 393 return 0; 394 395 err_remove_type_groups: 396 if (type) 397 device_remove_groups(dev, type->groups); 398 err_remove_class_attrs: 399 if (class) 400 device_remove_attributes(dev, class->dev_attrs); 401 402 return error; 403} 404 405static void device_remove_attrs(struct device *dev) 406{ 407 struct class *class = dev->class; 408 struct device_type *type = dev->type; 409 410 device_remove_groups(dev, dev->groups); 411 412 if (type) 413 device_remove_groups(dev, type->groups); 414 415 if (class) 416 device_remove_attributes(dev, class->dev_attrs); 417} 418 419 420static ssize_t show_dev(struct device *dev, struct device_attribute *attr, 421 char *buf) 422{ 423 return print_dev_t(buf, dev->devt); 424} 425 426/* 427 * devices_subsys - structure to be registered with kobject core. 428 */ 429 430decl_subsys(devices, &ktype_device, &device_uevent_ops); 431 432 433/** 434 * device_create_file - create sysfs attribute file for device. 435 * @dev: device. 436 * @attr: device attribute descriptor. 437 */ 438 439int device_create_file(struct device * dev, struct device_attribute * attr) 440{ 441 int error = 0; 442 if (get_device(dev)) { 443 error = sysfs_create_file(&dev->kobj, &attr->attr); 444 put_device(dev); 445 } 446 return error; 447} 448 449/** 450 * device_remove_file - remove sysfs attribute file. 451 * @dev: device. 452 * @attr: device attribute descriptor. 453 */ 454 455void device_remove_file(struct device * dev, struct device_attribute * attr) 456{ 457 if (get_device(dev)) { 458 sysfs_remove_file(&dev->kobj, &attr->attr); 459 put_device(dev); 460 } 461} 462 463/** 464 * device_create_bin_file - create sysfs binary attribute file for device. 465 * @dev: device. 466 * @attr: device binary attribute descriptor. 467 */ 468int device_create_bin_file(struct device *dev, struct bin_attribute *attr) 469{ 470 int error = -EINVAL; 471 if (dev) 472 error = sysfs_create_bin_file(&dev->kobj, attr); 473 return error; 474} 475EXPORT_SYMBOL_GPL(device_create_bin_file); 476 477/** 478 * device_remove_bin_file - remove sysfs binary attribute file 479 * @dev: device. 480 * @attr: device binary attribute descriptor. 481 */ 482void device_remove_bin_file(struct device *dev, struct bin_attribute *attr) 483{ 484 if (dev) 485 sysfs_remove_bin_file(&dev->kobj, attr); 486} 487EXPORT_SYMBOL_GPL(device_remove_bin_file); 488 489/** 490 * device_schedule_callback_owner - helper to schedule a callback for a device 491 * @dev: device. 492 * @func: callback function to invoke later. 493 * @owner: module owning the callback routine 494 * 495 * Attribute methods must not unregister themselves or their parent device 496 * (which would amount to the same thing). Attempts to do so will deadlock, 497 * since unregistration is mutually exclusive with driver callbacks. 498 * 499 * Instead methods can call this routine, which will attempt to allocate 500 * and schedule a workqueue request to call back @func with @dev as its 501 * argument in the workqueue's process context. @dev will be pinned until 502 * @func returns. 503 * 504 * This routine is usually called via the inline device_schedule_callback(), 505 * which automatically sets @owner to THIS_MODULE. 506 * 507 * Returns 0 if the request was submitted, -ENOMEM if storage could not 508 * be allocated, -ENODEV if a reference to @owner isn't available. 509 * 510 * NOTE: This routine won't work if CONFIG_SYSFS isn't set! It uses an 511 * underlying sysfs routine (since it is intended for use by attribute 512 * methods), and if sysfs isn't available you'll get nothing but -ENOSYS. 513 */ 514int device_schedule_callback_owner(struct device *dev, 515 void (*func)(struct device *), struct module *owner) 516{ 517 return sysfs_schedule_callback(&dev->kobj, 518 (void (*)(void *)) func, dev, owner); 519} 520EXPORT_SYMBOL_GPL(device_schedule_callback_owner); 521 522static void klist_children_get(struct klist_node *n) 523{ 524 struct device *dev = container_of(n, struct device, knode_parent); 525 526 get_device(dev); 527} 528 529static void klist_children_put(struct klist_node *n) 530{ 531 struct device *dev = container_of(n, struct device, knode_parent); 532 533 put_device(dev); 534} 535 536 537/** 538 * device_initialize - init device structure. 539 * @dev: device. 540 * 541 * This prepares the device for use by other layers, 542 * including adding it to the device hierarchy. 543 * It is the first half of device_register(), if called by 544 * that, though it can also be called separately, so one 545 * may use @dev's fields (e.g. the refcount). 546 */ 547 548void device_initialize(struct device *dev) 549{ 550 kobj_set_kset_s(dev, devices_subsys); 551 kobject_init(&dev->kobj); 552 klist_init(&dev->klist_children, klist_children_get, 553 klist_children_put); 554 INIT_LIST_HEAD(&dev->dma_pools); 555 INIT_LIST_HEAD(&dev->node); 556 init_MUTEX(&dev->sem); 557 spin_lock_init(&dev->devres_lock); 558 INIT_LIST_HEAD(&dev->devres_head); 559 device_init_wakeup(dev, 0); 560 set_dev_node(dev, -1); 561} 562 563#ifdef CONFIG_SYSFS_DEPRECATED 564static struct kobject * get_device_parent(struct device *dev, 565 struct device *parent) 566{ 567 /* Set the parent to the class, not the parent device */ 568 /* this keeps sysfs from having a symlink to make old udevs happy */ 569 if (dev->class) 570 return &dev->class->subsys.kobj; 571 else if (parent) 572 return &parent->kobj; 573 574 return NULL; 575} 576#else 577static struct kobject *virtual_device_parent(struct device *dev) 578{ 579 static struct kobject *virtual_dir = NULL; 580 581 if (!virtual_dir) 582 virtual_dir = kobject_add_dir(&devices_subsys.kobj, "virtual"); 583 584 return virtual_dir; 585} 586 587static struct kobject * get_device_parent(struct device *dev, 588 struct device *parent) 589{ 590 if (dev->class) { 591 struct kobject *kobj = NULL; 592 struct kobject *parent_kobj; 593 struct kobject *k; 594 595 /* 596 * If we have no parent, we live in "virtual". 597 * Class-devices with a bus-device as parent, live 598 * in a class-directory to prevent namespace collisions. 599 */ 600 if (parent == NULL) 601 parent_kobj = virtual_device_parent(dev); 602 else if (parent->class) 603 return &parent->kobj; 604 else 605 parent_kobj = &parent->kobj; 606 607 /* find our class-directory at the parent and reference it */ 608 spin_lock(&dev->class->class_dirs.list_lock); 609 list_for_each_entry(k, &dev->class->class_dirs.list, entry) 610 if (k->parent == parent_kobj) { 611 kobj = kobject_get(k); 612 break; 613 } 614 spin_unlock(&dev->class->class_dirs.list_lock); 615 if (kobj) 616 return kobj; 617 618 /* or create a new class-directory at the parent device */ 619 return kobject_kset_add_dir(&dev->class->class_dirs, 620 parent_kobj, dev->class->name); 621 } 622 623 if (parent) 624 return &parent->kobj; 625 return NULL; 626} 627#endif 628 629static int setup_parent(struct device *dev, struct device *parent) 630{ 631 struct kobject *kobj; 632 kobj = get_device_parent(dev, parent); 633 if (IS_ERR(kobj)) 634 return PTR_ERR(kobj); 635 if (kobj) 636 dev->kobj.parent = kobj; 637 return 0; 638} 639 640/** 641 * device_add - add device to device hierarchy. 642 * @dev: device. 643 * 644 * This is part 2 of device_register(), though may be called 645 * separately _iff_ device_initialize() has been called separately. 646 * 647 * This adds it to the kobject hierarchy via kobject_add(), adds it 648 * to the global and sibling lists for the device, then 649 * adds it to the other relevant subsystems of the driver model. 650 */ 651int device_add(struct device *dev) 652{ 653 struct device *parent = NULL; 654 char *class_name = NULL; 655 struct class_interface *class_intf; 656 int error = -EINVAL; 657 658 dev = get_device(dev); 659 if (!dev || !strlen(dev->bus_id)) 660 goto Error; 661 662 pr_debug("DEV: registering device: ID = '%s'\n", dev->bus_id); 663 664 parent = get_device(dev->parent); 665 error = setup_parent(dev, parent); 666 if (error) 667 goto Error; 668 669 /* first, register with generic layer. */ 670 kobject_set_name(&dev->kobj, "%s", dev->bus_id); 671 error = kobject_add(&dev->kobj); 672 if (error) 673 goto Error; 674 675 /* notify platform of device entry */ 676 if (platform_notify) 677 platform_notify(dev); 678 679 /* notify clients of device entry (new way) */ 680 if (dev->bus) 681 blocking_notifier_call_chain(&dev->bus->bus_notifier, 682 BUS_NOTIFY_ADD_DEVICE, dev); 683 684 dev->uevent_attr.attr.name = "uevent"; 685 dev->uevent_attr.attr.mode = S_IRUGO | S_IWUSR; 686 if (dev->driver) 687 dev->uevent_attr.attr.owner = dev->driver->owner; 688 dev->uevent_attr.store = store_uevent; 689 dev->uevent_attr.show = show_uevent; 690 error = device_create_file(dev, &dev->uevent_attr); 691 if (error) 692 goto attrError; 693 694 if (MAJOR(dev->devt)) { 695 struct device_attribute *attr; 696 attr = kzalloc(sizeof(*attr), GFP_KERNEL); 697 if (!attr) { 698 error = -ENOMEM; 699 goto ueventattrError; 700 } 701 attr->attr.name = "dev"; 702 attr->attr.mode = S_IRUGO; 703 if (dev->driver) 704 attr->attr.owner = dev->driver->owner; 705 attr->show = show_dev; 706 error = device_create_file(dev, attr); 707 if (error) { 708 kfree(attr); 709 goto ueventattrError; 710 } 711 712 dev->devt_attr = attr; 713 } 714 715 if (dev->class) { 716 sysfs_create_link(&dev->kobj, &dev->class->subsys.kobj, 717 "subsystem"); 718 /* If this is not a "fake" compatible device, then create the 719 * symlink from the class to the device. */ 720 if (dev->kobj.parent != &dev->class->subsys.kobj) 721 sysfs_create_link(&dev->class->subsys.kobj, 722 &dev->kobj, dev->bus_id); 723 if (parent) { 724 sysfs_create_link(&dev->kobj, &dev->parent->kobj, 725 "device"); 726#ifdef CONFIG_SYSFS_DEPRECATED 727 class_name = make_class_name(dev->class->name, 728 &dev->kobj); 729 if (class_name) 730 sysfs_create_link(&dev->parent->kobj, 731 &dev->kobj, class_name); 732#endif 733 } 734 } 735 736 if ((error = device_add_attrs(dev))) 737 goto AttrsError; 738 if ((error = device_pm_add(dev))) 739 goto PMError; 740 if ((error = bus_add_device(dev))) 741 goto BusError; 742 kobject_uevent(&dev->kobj, KOBJ_ADD); 743 bus_attach_device(dev); 744 if (parent) 745 klist_add_tail(&dev->knode_parent, &parent->klist_children); 746 747 if (dev->class) { 748 down(&dev->class->sem); 749 /* tie the class to the device */ 750 list_add_tail(&dev->node, &dev->class->devices); 751 752 /* notify any interfaces that the device is here */ 753 list_for_each_entry(class_intf, &dev->class->interfaces, node) 754 if (class_intf->add_dev) 755 class_intf->add_dev(dev, class_intf); 756 up(&dev->class->sem); 757 } 758 Done: 759 kfree(class_name); 760 put_device(dev); 761 return error; 762 BusError: 763 device_pm_remove(dev); 764 PMError: 765 if (dev->bus) 766 blocking_notifier_call_chain(&dev->bus->bus_notifier, 767 BUS_NOTIFY_DEL_DEVICE, dev); 768 device_remove_attrs(dev); 769 AttrsError: 770 if (dev->devt_attr) { 771 device_remove_file(dev, dev->devt_attr); 772 kfree(dev->devt_attr); 773 } 774 775 if (dev->class) { 776 sysfs_remove_link(&dev->kobj, "subsystem"); 777 /* If this is not a "fake" compatible device, remove the 778 * symlink from the class to the device. */ 779 if (dev->kobj.parent != &dev->class->subsys.kobj) 780 sysfs_remove_link(&dev->class->subsys.kobj, 781 dev->bus_id); 782 if (parent) { 783#ifdef CONFIG_SYSFS_DEPRECATED 784 char *class_name = make_class_name(dev->class->name, 785 &dev->kobj); 786 if (class_name) 787 sysfs_remove_link(&dev->parent->kobj, 788 class_name); 789 kfree(class_name); 790#endif 791 sysfs_remove_link(&dev->kobj, "device"); 792 } 793 } 794 ueventattrError: 795 device_remove_file(dev, &dev->uevent_attr); 796 attrError: 797 kobject_uevent(&dev->kobj, KOBJ_REMOVE); 798 kobject_del(&dev->kobj); 799 Error: 800 if (parent) 801 put_device(parent); 802 goto Done; 803} 804 805 806/** 807 * device_register - register a device with the system. 808 * @dev: pointer to the device structure 809 * 810 * This happens in two clean steps - initialize the device 811 * and add it to the system. The two steps can be called 812 * separately, but this is the easiest and most common. 813 * I.e. you should only call the two helpers separately if 814 * have a clearly defined need to use and refcount the device 815 * before it is added to the hierarchy. 816 */ 817 818int device_register(struct device *dev) 819{ 820 device_initialize(dev); 821 return device_add(dev); 822} 823 824 825/** 826 * get_device - increment reference count for device. 827 * @dev: device. 828 * 829 * This simply forwards the call to kobject_get(), though 830 * we do take care to provide for the case that we get a NULL 831 * pointer passed in. 832 */ 833 834struct device * get_device(struct device * dev) 835{ 836 return dev ? to_dev(kobject_get(&dev->kobj)) : NULL; 837} 838 839 840/** 841 * put_device - decrement reference count. 842 * @dev: device in question. 843 */ 844void put_device(struct device * dev) 845{ 846 if (dev) 847 kobject_put(&dev->kobj); 848} 849 850 851/** 852 * device_del - delete device from system. 853 * @dev: device. 854 * 855 * This is the first part of the device unregistration 856 * sequence. This removes the device from the lists we control 857 * from here, has it removed from the other driver model 858 * subsystems it was added to in device_add(), and removes it 859 * from the kobject hierarchy. 860 * 861 * NOTE: this should be called manually _iff_ device_add() was 862 * also called manually. 863 */ 864 865void device_del(struct device * dev) 866{ 867 struct device * parent = dev->parent; 868 struct class_interface *class_intf; 869 870 if (parent) 871 klist_del(&dev->knode_parent); 872 if (dev->devt_attr) { 873 device_remove_file(dev, dev->devt_attr); 874 kfree(dev->devt_attr); 875 } 876 if (dev->class) { 877 sysfs_remove_link(&dev->kobj, "subsystem"); 878 /* If this is not a "fake" compatible device, remove the 879 * symlink from the class to the device. */ 880 if (dev->kobj.parent != &dev->class->subsys.kobj) 881 sysfs_remove_link(&dev->class->subsys.kobj, 882 dev->bus_id); 883 if (parent) { 884#ifdef CONFIG_SYSFS_DEPRECATED 885 char *class_name = make_class_name(dev->class->name, 886 &dev->kobj); 887 if (class_name) 888 sysfs_remove_link(&dev->parent->kobj, 889 class_name); 890 kfree(class_name); 891#endif 892 sysfs_remove_link(&dev->kobj, "device"); 893 } 894 895 down(&dev->class->sem); 896 /* notify any interfaces that the device is now gone */ 897 list_for_each_entry(class_intf, &dev->class->interfaces, node) 898 if (class_intf->remove_dev) 899 class_intf->remove_dev(dev, class_intf); 900 /* remove the device from the class list */ 901 list_del_init(&dev->node); 902 up(&dev->class->sem); 903 904 /* If we live in a parent class-directory, unreference it */ 905 if (dev->kobj.parent->kset == &dev->class->class_dirs) { 906 struct device *d; 907 int other = 0; 908 909 /* 910 * if we are the last child of our class, delete 911 * our class-directory at this parent 912 */ 913 down(&dev->class->sem); 914 list_for_each_entry(d, &dev->class->devices, node) { 915 if (d == dev) 916 continue; 917 if (d->kobj.parent == dev->kobj.parent) { 918 other = 1; 919 break; 920 } 921 } 922 if (!other) 923 kobject_del(dev->kobj.parent); 924 925 kobject_put(dev->kobj.parent); 926 up(&dev->class->sem); 927 } 928 } 929 device_remove_file(dev, &dev->uevent_attr); 930 device_remove_attrs(dev); 931 bus_remove_device(dev); 932 933 /* 934 * Some platform devices are driven without driver attached 935 * and managed resources may have been acquired. Make sure 936 * all resources are released. 937 */ 938 devres_release_all(dev); 939 940 /* Notify the platform of the removal, in case they 941 * need to do anything... 942 */ 943 if (platform_notify_remove) 944 platform_notify_remove(dev); 945 if (dev->bus) 946 blocking_notifier_call_chain(&dev->bus->bus_notifier, 947 BUS_NOTIFY_DEL_DEVICE, dev); 948 device_pm_remove(dev); 949 kobject_uevent(&dev->kobj, KOBJ_REMOVE); 950 kobject_del(&dev->kobj); 951 if (parent) 952 put_device(parent); 953} 954 955/** 956 * device_unregister - unregister device from system. 957 * @dev: device going away. 958 * 959 * We do this in two parts, like we do device_register(). First, 960 * we remove it from all the subsystems with device_del(), then 961 * we decrement the reference count via put_device(). If that 962 * is the final reference count, the device will be cleaned up 963 * via device_release() above. Otherwise, the structure will 964 * stick around until the final reference to the device is dropped. 965 */ 966void device_unregister(struct device * dev) 967{ 968 pr_debug("DEV: Unregistering device. ID = '%s'\n", dev->bus_id); 969 device_del(dev); 970 put_device(dev); 971} 972 973 974static struct device * next_device(struct klist_iter * i) 975{ 976 struct klist_node * n = klist_next(i); 977 return n ? container_of(n, struct device, knode_parent) : NULL; 978} 979 980/** 981 * device_for_each_child - device child iterator. 982 * @parent: parent struct device. 983 * @data: data for the callback. 984 * @fn: function to be called for each device. 985 * 986 * Iterate over @parent's child devices, and call @fn for each, 987 * passing it @data. 988 * 989 * We check the return of @fn each time. If it returns anything 990 * other than 0, we break out and return that value. 991 */ 992int device_for_each_child(struct device * parent, void * data, 993 int (*fn)(struct device *, void *)) 994{ 995 struct klist_iter i; 996 struct device * child; 997 int error = 0; 998 999 klist_iter_init(&parent->klist_children, &i); 1000 while ((child = next_device(&i)) && !error) 1001 error = fn(child, data); 1002 klist_iter_exit(&i); 1003 return error; 1004} 1005 1006/** 1007 * device_find_child - device iterator for locating a particular device. 1008 * @parent: parent struct device 1009 * @data: Data to pass to match function 1010 * @match: Callback function to check device 1011 * 1012 * This is similar to the device_for_each_child() function above, but it 1013 * returns a reference to a device that is 'found' for later use, as 1014 * determined by the @match callback. 1015 * 1016 * The callback should return 0 if the device doesn't match and non-zero 1017 * if it does. If the callback returns non-zero and a reference to the 1018 * current device can be obtained, this function will return to the caller 1019 * and not iterate over any more devices. 1020 */ 1021struct device * device_find_child(struct device *parent, void *data, 1022 int (*match)(struct device *, void *)) 1023{ 1024 struct klist_iter i; 1025 struct device *child; 1026 1027 if (!parent) 1028 return NULL; 1029 1030 klist_iter_init(&parent->klist_children, &i); 1031 while ((child = next_device(&i))) 1032 if (match(child, data) && get_device(child)) 1033 break; 1034 klist_iter_exit(&i); 1035 return child; 1036} 1037 1038int __init devices_init(void) 1039{ 1040 return subsystem_register(&devices_subsys); 1041} 1042 1043EXPORT_SYMBOL_GPL(device_for_each_child); 1044EXPORT_SYMBOL_GPL(device_find_child); 1045 1046EXPORT_SYMBOL_GPL(device_initialize); 1047EXPORT_SYMBOL_GPL(device_add); 1048EXPORT_SYMBOL_GPL(device_register); 1049 1050EXPORT_SYMBOL_GPL(device_del); 1051EXPORT_SYMBOL_GPL(device_unregister); 1052EXPORT_SYMBOL_GPL(get_device); 1053EXPORT_SYMBOL_GPL(put_device); 1054 1055EXPORT_SYMBOL_GPL(device_create_file); 1056EXPORT_SYMBOL_GPL(device_remove_file); 1057 1058 1059static void device_create_release(struct device *dev) 1060{ 1061 pr_debug("%s called for %s\n", __FUNCTION__, dev->bus_id); 1062 kfree(dev); 1063} 1064 1065/** 1066 * device_create - creates a device and registers it with sysfs 1067 * @class: pointer to the struct class that this device should be registered to 1068 * @parent: pointer to the parent struct device of this new device, if any 1069 * @devt: the dev_t for the char device to be added 1070 * @fmt: string for the device's name 1071 * 1072 * This function can be used by char device classes. A struct device 1073 * will be created in sysfs, registered to the specified class. 1074 * 1075 * A "dev" file will be created, showing the dev_t for the device, if 1076 * the dev_t is not 0,0. 1077 * If a pointer to a parent struct device is passed in, the newly created 1078 * struct device will be a child of that device in sysfs. 1079 * The pointer to the struct device will be returned from the call. 1080 * Any further sysfs files that might be required can be created using this 1081 * pointer. 1082 * 1083 * Note: the struct class passed to this function must have previously 1084 * been created with a call to class_create(). 1085 */ 1086struct device *device_create(struct class *class, struct device *parent, 1087 dev_t devt, const char *fmt, ...) 1088{ 1089 va_list args; 1090 struct device *dev = NULL; 1091 int retval = -ENODEV; 1092 1093 if (class == NULL || IS_ERR(class)) 1094 goto error; 1095 1096 dev = kzalloc(sizeof(*dev), GFP_KERNEL); 1097 if (!dev) { 1098 retval = -ENOMEM; 1099 goto error; 1100 } 1101 1102 dev->devt = devt; 1103 dev->class = class; 1104 dev->parent = parent; 1105 dev->release = device_create_release; 1106 1107 va_start(args, fmt); 1108 vsnprintf(dev->bus_id, BUS_ID_SIZE, fmt, args); 1109 va_end(args); 1110 retval = device_register(dev); 1111 if (retval) 1112 goto error; 1113 1114 return dev; 1115 1116error: 1117 kfree(dev); 1118 return ERR_PTR(retval); 1119} 1120EXPORT_SYMBOL_GPL(device_create); 1121 1122/** 1123 * device_destroy - removes a device that was created with device_create() 1124 * @class: pointer to the struct class that this device was registered with 1125 * @devt: the dev_t of the device that was previously registered 1126 * 1127 * This call unregisters and cleans up a device that was created with a 1128 * call to device_create(). 1129 */ 1130void device_destroy(struct class *class, dev_t devt) 1131{ 1132 struct device *dev = NULL; 1133 struct device *dev_tmp; 1134 1135 down(&class->sem); 1136 list_for_each_entry(dev_tmp, &class->devices, node) { 1137 if (dev_tmp->devt == devt) { 1138 dev = dev_tmp; 1139 break; 1140 } 1141 } 1142 up(&class->sem); 1143 1144 if (dev) 1145 device_unregister(dev); 1146} 1147EXPORT_SYMBOL_GPL(device_destroy); 1148 1149/** 1150 * device_rename - renames a device 1151 * @dev: the pointer to the struct device to be renamed 1152 * @new_name: the new name of the device 1153 */ 1154int device_rename(struct device *dev, char *new_name) 1155{ 1156 char *old_class_name = NULL; 1157 char *new_class_name = NULL; 1158 char *old_symlink_name = NULL; 1159 int error; 1160 1161 dev = get_device(dev); 1162 if (!dev) 1163 return -EINVAL; 1164 1165 pr_debug("DEVICE: renaming '%s' to '%s'\n", dev->bus_id, new_name); 1166 1167#ifdef CONFIG_SYSFS_DEPRECATED 1168 if ((dev->class) && (dev->parent)) 1169 old_class_name = make_class_name(dev->class->name, &dev->kobj); 1170#endif 1171 1172 if (dev->class) { 1173 old_symlink_name = kmalloc(BUS_ID_SIZE, GFP_KERNEL); 1174 if (!old_symlink_name) { 1175 error = -ENOMEM; 1176 goto out_free_old_class; 1177 } 1178 strlcpy(old_symlink_name, dev->bus_id, BUS_ID_SIZE); 1179 } 1180 1181 strlcpy(dev->bus_id, new_name, BUS_ID_SIZE); 1182 1183 error = kobject_rename(&dev->kobj, new_name); 1184 1185#ifdef CONFIG_SYSFS_DEPRECATED 1186 if (old_class_name) { 1187 new_class_name = make_class_name(dev->class->name, &dev->kobj); 1188 if (new_class_name) { 1189 sysfs_create_link(&dev->parent->kobj, &dev->kobj, 1190 new_class_name); 1191 sysfs_remove_link(&dev->parent->kobj, old_class_name); 1192 } 1193 } 1194#endif 1195 1196 if (dev->class) { 1197 sysfs_remove_link(&dev->class->subsys.kobj, 1198 old_symlink_name); 1199 sysfs_create_link(&dev->class->subsys.kobj, &dev->kobj, 1200 dev->bus_id); 1201 } 1202 put_device(dev); 1203 1204 kfree(new_class_name); 1205 kfree(old_symlink_name); 1206 out_free_old_class: 1207 kfree(old_class_name); 1208 1209 return error; 1210} 1211EXPORT_SYMBOL_GPL(device_rename); 1212 1213static int device_move_class_links(struct device *dev, 1214 struct device *old_parent, 1215 struct device *new_parent) 1216{ 1217 int error = 0; 1218#ifdef CONFIG_SYSFS_DEPRECATED 1219 char *class_name; 1220 1221 class_name = make_class_name(dev->class->name, &dev->kobj); 1222 if (!class_name) { 1223 error = -ENOMEM; 1224 goto out; 1225 } 1226 if (old_parent) { 1227 sysfs_remove_link(&dev->kobj, "device"); 1228 sysfs_remove_link(&old_parent->kobj, class_name); 1229 } 1230 if (new_parent) { 1231 error = sysfs_create_link(&dev->kobj, &new_parent->kobj, 1232 "device"); 1233 if (error) 1234 goto out; 1235 error = sysfs_create_link(&new_parent->kobj, &dev->kobj, 1236 class_name); 1237 if (error) 1238 sysfs_remove_link(&dev->kobj, "device"); 1239 } 1240 else 1241 error = 0; 1242out: 1243 kfree(class_name); 1244 return error; 1245#else 1246 if (old_parent) 1247 sysfs_remove_link(&dev->kobj, "device"); 1248 if (new_parent) 1249 error = sysfs_create_link(&dev->kobj, &new_parent->kobj, 1250 "device"); 1251 return error; 1252#endif 1253} 1254 1255/** 1256 * device_move - moves a device to a new parent 1257 * @dev: the pointer to the struct device to be moved 1258 * @new_parent: the new parent of the device (can by NULL) 1259 */ 1260int device_move(struct device *dev, struct device *new_parent) 1261{ 1262 int error; 1263 struct device *old_parent; 1264 struct kobject *new_parent_kobj; 1265 1266 dev = get_device(dev); 1267 if (!dev) 1268 return -EINVAL; 1269 1270 new_parent = get_device(new_parent); 1271 new_parent_kobj = get_device_parent (dev, new_parent); 1272 if (IS_ERR(new_parent_kobj)) { 1273 error = PTR_ERR(new_parent_kobj); 1274 put_device(new_parent); 1275 goto out; 1276 } 1277 pr_debug("DEVICE: moving '%s' to '%s'\n", dev->bus_id, 1278 new_parent ? new_parent->bus_id : "<NULL>"); 1279 error = kobject_move(&dev->kobj, new_parent_kobj); 1280 if (error) { 1281 put_device(new_parent); 1282 goto out; 1283 } 1284 old_parent = dev->parent; 1285 dev->parent = new_parent; 1286 if (old_parent) 1287 klist_remove(&dev->knode_parent); 1288 if (new_parent) 1289 klist_add_tail(&dev->knode_parent, &new_parent->klist_children); 1290 if (!dev->class) 1291 goto out_put; 1292 error = device_move_class_links(dev, old_parent, new_parent); 1293 if (error) { 1294 /* We ignore errors on cleanup since we're hosed anyway... */ 1295 device_move_class_links(dev, new_parent, old_parent); 1296 if (!kobject_move(&dev->kobj, &old_parent->kobj)) { 1297 if (new_parent) 1298 klist_remove(&dev->knode_parent); 1299 if (old_parent) 1300 klist_add_tail(&dev->knode_parent, 1301 &old_parent->klist_children); 1302 } 1303 put_device(new_parent); 1304 goto out; 1305 } 1306out_put: 1307 put_device(old_parent); 1308out: 1309 put_device(dev); 1310 return error; 1311} 1312 1313EXPORT_SYMBOL_GPL(device_move); 1314