1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * drivers/base/core.c - core driver model code (device registration, etc) 4 * 5 * Copyright (c) 2002-3 Patrick Mochel 6 * Copyright (c) 2002-3 Open Source Development Labs 7 * Copyright (c) 2006 Greg Kroah-Hartman <gregkh@suse.de> 8 * Copyright (c) 2006 Novell, Inc. 9 */ 10 11 #include <linux/acpi.h> 12 #include <linux/cpufreq.h> 13 #include <linux/device.h> 14 #include <linux/err.h> 15 #include <linux/fwnode.h> 16 #include <linux/init.h> 17 #include <linux/module.h> 18 #include <linux/slab.h> 19 #include <linux/string.h> 20 #include <linux/kdev_t.h> 21 #include <linux/notifier.h> 22 #include <linux/of.h> 23 #include <linux/of_device.h> 24 #include <linux/blkdev.h> 25 #include <linux/mutex.h> 26 #include <linux/pm_runtime.h> 27 #include <linux/netdevice.h> 28 #include <linux/sched/signal.h> 29 #include <linux/sched/mm.h> 30 #include <linux/swiotlb.h> 31 #include <linux/sysfs.h> 32 #include <linux/dma-map-ops.h> /* for dma_default_coherent */ 33 34 #include "base.h" 35 #include "power/power.h" 36 37 #ifdef CONFIG_SYSFS_DEPRECATED 38 #ifdef CONFIG_SYSFS_DEPRECATED_V2 39 long sysfs_deprecated = 1; 40 #else 41 long sysfs_deprecated = 0; 42 #endif 43 static int __init sysfs_deprecated_setup(char *arg) 44 { 45 return kstrtol(arg, 10, &sysfs_deprecated); 46 } 47 early_param("sysfs.deprecated", sysfs_deprecated_setup); 48 #endif 49 50 /* Device links support. */ 51 static LIST_HEAD(deferred_sync); 52 static unsigned int defer_sync_state_count = 1; 53 static DEFINE_MUTEX(fwnode_link_lock); 54 static bool fw_devlink_is_permissive(void); 55 static bool fw_devlink_drv_reg_done; 56 57 /** 58 * fwnode_link_add - Create a link between two fwnode_handles. 59 * @con: Consumer end of the link. 60 * @sup: Supplier end of the link. 61 * 62 * Create a fwnode link between fwnode handles @con and @sup. The fwnode link 63 * represents the detail that the firmware lists @sup fwnode as supplying a 64 * resource to @con. 65 * 66 * The driver core will use the fwnode link to create a device link between the 67 * two device objects corresponding to @con and @sup when they are created. The 68 * driver core will automatically delete the fwnode link between @con and @sup 69 * after doing that. 70 * 71 * Attempts to create duplicate links between the same pair of fwnode handles 72 * are ignored and there is no reference counting. 73 */ 74 int fwnode_link_add(struct fwnode_handle *con, struct fwnode_handle *sup) 75 { 76 struct fwnode_link *link; 77 int ret = 0; 78 79 mutex_lock(&fwnode_link_lock); 80 81 list_for_each_entry(link, &sup->consumers, s_hook) 82 if (link->consumer == con) 83 goto out; 84 85 link = kzalloc(sizeof(*link), GFP_KERNEL); 86 if (!link) { 87 ret = -ENOMEM; 88 goto out; 89 } 90 91 link->supplier = sup; 92 INIT_LIST_HEAD(&link->s_hook); 93 link->consumer = con; 94 INIT_LIST_HEAD(&link->c_hook); 95 96 list_add(&link->s_hook, &sup->consumers); 97 list_add(&link->c_hook, &con->suppliers); 98 pr_debug("%pfwP Linked as a fwnode consumer to %pfwP\n", 99 con, sup); 100 out: 101 mutex_unlock(&fwnode_link_lock); 102 103 return ret; 104 } 105 106 /** 107 * __fwnode_link_del - Delete a link between two fwnode_handles. 108 * @link: the fwnode_link to be deleted 109 * 110 * The fwnode_link_lock needs to be held when this function is called. 111 */ 112 static void __fwnode_link_del(struct fwnode_link *link) 113 { 114 pr_debug("%pfwP Dropping the fwnode link to %pfwP\n", 115 link->consumer, link->supplier); 116 list_del(&link->s_hook); 117 list_del(&link->c_hook); 118 kfree(link); 119 } 120 121 /** 122 * fwnode_links_purge_suppliers - Delete all supplier links of fwnode_handle. 123 * @fwnode: fwnode whose supplier links need to be deleted 124 * 125 * Deletes all supplier links connecting directly to @fwnode. 126 */ 127 static void fwnode_links_purge_suppliers(struct fwnode_handle *fwnode) 128 { 129 struct fwnode_link *link, *tmp; 130 131 mutex_lock(&fwnode_link_lock); 132 list_for_each_entry_safe(link, tmp, &fwnode->suppliers, c_hook) 133 __fwnode_link_del(link); 134 mutex_unlock(&fwnode_link_lock); 135 } 136 137 /** 138 * fwnode_links_purge_consumers - Delete all consumer links of fwnode_handle. 139 * @fwnode: fwnode whose consumer links need to be deleted 140 * 141 * Deletes all consumer links connecting directly to @fwnode. 142 */ 143 static void fwnode_links_purge_consumers(struct fwnode_handle *fwnode) 144 { 145 struct fwnode_link *link, *tmp; 146 147 mutex_lock(&fwnode_link_lock); 148 list_for_each_entry_safe(link, tmp, &fwnode->consumers, s_hook) 149 __fwnode_link_del(link); 150 mutex_unlock(&fwnode_link_lock); 151 } 152 153 /** 154 * fwnode_links_purge - Delete all links connected to a fwnode_handle. 155 * @fwnode: fwnode whose links needs to be deleted 156 * 157 * Deletes all links connecting directly to a fwnode. 158 */ 159 void fwnode_links_purge(struct fwnode_handle *fwnode) 160 { 161 fwnode_links_purge_suppliers(fwnode); 162 fwnode_links_purge_consumers(fwnode); 163 } 164 165 void fw_devlink_purge_absent_suppliers(struct fwnode_handle *fwnode) 166 { 167 struct fwnode_handle *child; 168 169 /* Don't purge consumer links of an added child */ 170 if (fwnode->dev) 171 return; 172 173 fwnode->flags |= FWNODE_FLAG_NOT_DEVICE; 174 fwnode_links_purge_consumers(fwnode); 175 176 fwnode_for_each_available_child_node(fwnode, child) 177 fw_devlink_purge_absent_suppliers(child); 178 } 179 EXPORT_SYMBOL_GPL(fw_devlink_purge_absent_suppliers); 180 181 #ifdef CONFIG_SRCU 182 static DEFINE_MUTEX(device_links_lock); 183 DEFINE_STATIC_SRCU(device_links_srcu); 184 185 static inline void device_links_write_lock(void) 186 { 187 mutex_lock(&device_links_lock); 188 } 189 190 static inline void device_links_write_unlock(void) 191 { 192 mutex_unlock(&device_links_lock); 193 } 194 195 int device_links_read_lock(void) __acquires(&device_links_srcu) 196 { 197 return srcu_read_lock(&device_links_srcu); 198 } 199 200 void device_links_read_unlock(int idx) __releases(&device_links_srcu) 201 { 202 srcu_read_unlock(&device_links_srcu, idx); 203 } 204 205 int device_links_read_lock_held(void) 206 { 207 return srcu_read_lock_held(&device_links_srcu); 208 } 209 210 static void device_link_synchronize_removal(void) 211 { 212 synchronize_srcu(&device_links_srcu); 213 } 214 215 static void device_link_remove_from_lists(struct device_link *link) 216 { 217 list_del_rcu(&link->s_node); 218 list_del_rcu(&link->c_node); 219 } 220 #else /* !CONFIG_SRCU */ 221 static DECLARE_RWSEM(device_links_lock); 222 223 static inline void device_links_write_lock(void) 224 { 225 down_write(&device_links_lock); 226 } 227 228 static inline void device_links_write_unlock(void) 229 { 230 up_write(&device_links_lock); 231 } 232 233 int device_links_read_lock(void) 234 { 235 down_read(&device_links_lock); 236 return 0; 237 } 238 239 void device_links_read_unlock(int not_used) 240 { 241 up_read(&device_links_lock); 242 } 243 244 #ifdef CONFIG_DEBUG_LOCK_ALLOC 245 int device_links_read_lock_held(void) 246 { 247 return lockdep_is_held(&device_links_lock); 248 } 249 #endif 250 251 static inline void device_link_synchronize_removal(void) 252 { 253 } 254 255 static void device_link_remove_from_lists(struct device_link *link) 256 { 257 list_del(&link->s_node); 258 list_del(&link->c_node); 259 } 260 #endif /* !CONFIG_SRCU */ 261 262 static bool device_is_ancestor(struct device *dev, struct device *target) 263 { 264 while (target->parent) { 265 target = target->parent; 266 if (dev == target) 267 return true; 268 } 269 return false; 270 } 271 272 /** 273 * device_is_dependent - Check if one device depends on another one 274 * @dev: Device to check dependencies for. 275 * @target: Device to check against. 276 * 277 * Check if @target depends on @dev or any device dependent on it (its child or 278 * its consumer etc). Return 1 if that is the case or 0 otherwise. 279 */ 280 int device_is_dependent(struct device *dev, void *target) 281 { 282 struct device_link *link; 283 int ret; 284 285 /* 286 * The "ancestors" check is needed to catch the case when the target 287 * device has not been completely initialized yet and it is still 288 * missing from the list of children of its parent device. 289 */ 290 if (dev == target || device_is_ancestor(dev, target)) 291 return 1; 292 293 ret = device_for_each_child(dev, target, device_is_dependent); 294 if (ret) 295 return ret; 296 297 list_for_each_entry(link, &dev->links.consumers, s_node) { 298 if ((link->flags & ~DL_FLAG_INFERRED) == 299 (DL_FLAG_SYNC_STATE_ONLY | DL_FLAG_MANAGED)) 300 continue; 301 302 if (link->consumer == target) 303 return 1; 304 305 ret = device_is_dependent(link->consumer, target); 306 if (ret) 307 break; 308 } 309 return ret; 310 } 311 312 static void device_link_init_status(struct device_link *link, 313 struct device *consumer, 314 struct device *supplier) 315 { 316 switch (supplier->links.status) { 317 case DL_DEV_PROBING: 318 switch (consumer->links.status) { 319 case DL_DEV_PROBING: 320 /* 321 * A consumer driver can create a link to a supplier 322 * that has not completed its probing yet as long as it 323 * knows that the supplier is already functional (for 324 * example, it has just acquired some resources from the 325 * supplier). 326 */ 327 link->status = DL_STATE_CONSUMER_PROBE; 328 break; 329 default: 330 link->status = DL_STATE_DORMANT; 331 break; 332 } 333 break; 334 case DL_DEV_DRIVER_BOUND: 335 switch (consumer->links.status) { 336 case DL_DEV_PROBING: 337 link->status = DL_STATE_CONSUMER_PROBE; 338 break; 339 case DL_DEV_DRIVER_BOUND: 340 link->status = DL_STATE_ACTIVE; 341 break; 342 default: 343 link->status = DL_STATE_AVAILABLE; 344 break; 345 } 346 break; 347 case DL_DEV_UNBINDING: 348 link->status = DL_STATE_SUPPLIER_UNBIND; 349 break; 350 default: 351 link->status = DL_STATE_DORMANT; 352 break; 353 } 354 } 355 356 static int device_reorder_to_tail(struct device *dev, void *not_used) 357 { 358 struct device_link *link; 359 360 /* 361 * Devices that have not been registered yet will be put to the ends 362 * of the lists during the registration, so skip them here. 363 */ 364 if (device_is_registered(dev)) 365 devices_kset_move_last(dev); 366 367 if (device_pm_initialized(dev)) 368 device_pm_move_last(dev); 369 370 device_for_each_child(dev, NULL, device_reorder_to_tail); 371 list_for_each_entry(link, &dev->links.consumers, s_node) { 372 if ((link->flags & ~DL_FLAG_INFERRED) == 373 (DL_FLAG_SYNC_STATE_ONLY | DL_FLAG_MANAGED)) 374 continue; 375 device_reorder_to_tail(link->consumer, NULL); 376 } 377 378 return 0; 379 } 380 381 /** 382 * device_pm_move_to_tail - Move set of devices to the end of device lists 383 * @dev: Device to move 384 * 385 * This is a device_reorder_to_tail() wrapper taking the requisite locks. 386 * 387 * It moves the @dev along with all of its children and all of its consumers 388 * to the ends of the device_kset and dpm_list, recursively. 389 */ 390 void device_pm_move_to_tail(struct device *dev) 391 { 392 int idx; 393 394 idx = device_links_read_lock(); 395 device_pm_lock(); 396 device_reorder_to_tail(dev, NULL); 397 device_pm_unlock(); 398 device_links_read_unlock(idx); 399 } 400 401 #define to_devlink(dev) container_of((dev), struct device_link, link_dev) 402 403 static ssize_t status_show(struct device *dev, 404 struct device_attribute *attr, char *buf) 405 { 406 const char *output; 407 408 switch (to_devlink(dev)->status) { 409 case DL_STATE_NONE: 410 output = "not tracked"; 411 break; 412 case DL_STATE_DORMANT: 413 output = "dormant"; 414 break; 415 case DL_STATE_AVAILABLE: 416 output = "available"; 417 break; 418 case DL_STATE_CONSUMER_PROBE: 419 output = "consumer probing"; 420 break; 421 case DL_STATE_ACTIVE: 422 output = "active"; 423 break; 424 case DL_STATE_SUPPLIER_UNBIND: 425 output = "supplier unbinding"; 426 break; 427 default: 428 output = "unknown"; 429 break; 430 } 431 432 return sysfs_emit(buf, "%s\n", output); 433 } 434 static DEVICE_ATTR_RO(status); 435 436 static ssize_t auto_remove_on_show(struct device *dev, 437 struct device_attribute *attr, char *buf) 438 { 439 struct device_link *link = to_devlink(dev); 440 const char *output; 441 442 if (link->flags & DL_FLAG_AUTOREMOVE_SUPPLIER) 443 output = "supplier unbind"; 444 else if (link->flags & DL_FLAG_AUTOREMOVE_CONSUMER) 445 output = "consumer unbind"; 446 else 447 output = "never"; 448 449 return sysfs_emit(buf, "%s\n", output); 450 } 451 static DEVICE_ATTR_RO(auto_remove_on); 452 453 static ssize_t runtime_pm_show(struct device *dev, 454 struct device_attribute *attr, char *buf) 455 { 456 struct device_link *link = to_devlink(dev); 457 458 return sysfs_emit(buf, "%d\n", !!(link->flags & DL_FLAG_PM_RUNTIME)); 459 } 460 static DEVICE_ATTR_RO(runtime_pm); 461 462 static ssize_t sync_state_only_show(struct device *dev, 463 struct device_attribute *attr, char *buf) 464 { 465 struct device_link *link = to_devlink(dev); 466 467 return sysfs_emit(buf, "%d\n", 468 !!(link->flags & DL_FLAG_SYNC_STATE_ONLY)); 469 } 470 static DEVICE_ATTR_RO(sync_state_only); 471 472 static struct attribute *devlink_attrs[] = { 473 &dev_attr_status.attr, 474 &dev_attr_auto_remove_on.attr, 475 &dev_attr_runtime_pm.attr, 476 &dev_attr_sync_state_only.attr, 477 NULL, 478 }; 479 ATTRIBUTE_GROUPS(devlink); 480 481 static void device_link_release_fn(struct work_struct *work) 482 { 483 struct device_link *link = container_of(work, struct device_link, rm_work); 484 485 /* Ensure that all references to the link object have been dropped. */ 486 device_link_synchronize_removal(); 487 488 pm_runtime_release_supplier(link, true); 489 490 put_device(link->consumer); 491 put_device(link->supplier); 492 kfree(link); 493 } 494 495 static void devlink_dev_release(struct device *dev) 496 { 497 struct device_link *link = to_devlink(dev); 498 499 INIT_WORK(&link->rm_work, device_link_release_fn); 500 /* 501 * It may take a while to complete this work because of the SRCU 502 * synchronization in device_link_release_fn() and if the consumer or 503 * supplier devices get deleted when it runs, so put it into the "long" 504 * workqueue. 505 */ 506 queue_work(system_long_wq, &link->rm_work); 507 } 508 509 static struct class devlink_class = { 510 .name = "devlink", 511 .owner = THIS_MODULE, 512 .dev_groups = devlink_groups, 513 .dev_release = devlink_dev_release, 514 }; 515 516 static int devlink_add_symlinks(struct device *dev, 517 struct class_interface *class_intf) 518 { 519 int ret; 520 size_t len; 521 struct device_link *link = to_devlink(dev); 522 struct device *sup = link->supplier; 523 struct device *con = link->consumer; 524 char *buf; 525 526 len = max(strlen(dev_bus_name(sup)) + strlen(dev_name(sup)), 527 strlen(dev_bus_name(con)) + strlen(dev_name(con))); 528 len += strlen(":"); 529 len += strlen("supplier:") + 1; 530 buf = kzalloc(len, GFP_KERNEL); 531 if (!buf) 532 return -ENOMEM; 533 534 ret = sysfs_create_link(&link->link_dev.kobj, &sup->kobj, "supplier"); 535 if (ret) 536 goto out; 537 538 ret = sysfs_create_link(&link->link_dev.kobj, &con->kobj, "consumer"); 539 if (ret) 540 goto err_con; 541 542 snprintf(buf, len, "consumer:%s:%s", dev_bus_name(con), dev_name(con)); 543 ret = sysfs_create_link(&sup->kobj, &link->link_dev.kobj, buf); 544 if (ret) 545 goto err_con_dev; 546 547 snprintf(buf, len, "supplier:%s:%s", dev_bus_name(sup), dev_name(sup)); 548 ret = sysfs_create_link(&con->kobj, &link->link_dev.kobj, buf); 549 if (ret) 550 goto err_sup_dev; 551 552 goto out; 553 554 err_sup_dev: 555 snprintf(buf, len, "consumer:%s:%s", dev_bus_name(con), dev_name(con)); 556 sysfs_remove_link(&sup->kobj, buf); 557 err_con_dev: 558 sysfs_remove_link(&link->link_dev.kobj, "consumer"); 559 err_con: 560 sysfs_remove_link(&link->link_dev.kobj, "supplier"); 561 out: 562 kfree(buf); 563 return ret; 564 } 565 566 static void devlink_remove_symlinks(struct device *dev, 567 struct class_interface *class_intf) 568 { 569 struct device_link *link = to_devlink(dev); 570 size_t len; 571 struct device *sup = link->supplier; 572 struct device *con = link->consumer; 573 char *buf; 574 575 sysfs_remove_link(&link->link_dev.kobj, "consumer"); 576 sysfs_remove_link(&link->link_dev.kobj, "supplier"); 577 578 len = max(strlen(dev_bus_name(sup)) + strlen(dev_name(sup)), 579 strlen(dev_bus_name(con)) + strlen(dev_name(con))); 580 len += strlen(":"); 581 len += strlen("supplier:") + 1; 582 buf = kzalloc(len, GFP_KERNEL); 583 if (!buf) { 584 WARN(1, "Unable to properly free device link symlinks!\n"); 585 return; 586 } 587 588 if (device_is_registered(con)) { 589 snprintf(buf, len, "supplier:%s:%s", dev_bus_name(sup), dev_name(sup)); 590 sysfs_remove_link(&con->kobj, buf); 591 } 592 snprintf(buf, len, "consumer:%s:%s", dev_bus_name(con), dev_name(con)); 593 sysfs_remove_link(&sup->kobj, buf); 594 kfree(buf); 595 } 596 597 static struct class_interface devlink_class_intf = { 598 .class = &devlink_class, 599 .add_dev = devlink_add_symlinks, 600 .remove_dev = devlink_remove_symlinks, 601 }; 602 603 static int __init devlink_class_init(void) 604 { 605 int ret; 606 607 ret = class_register(&devlink_class); 608 if (ret) 609 return ret; 610 611 ret = class_interface_register(&devlink_class_intf); 612 if (ret) 613 class_unregister(&devlink_class); 614 615 return ret; 616 } 617 postcore_initcall(devlink_class_init); 618 619 #define DL_MANAGED_LINK_FLAGS (DL_FLAG_AUTOREMOVE_CONSUMER | \ 620 DL_FLAG_AUTOREMOVE_SUPPLIER | \ 621 DL_FLAG_AUTOPROBE_CONSUMER | \ 622 DL_FLAG_SYNC_STATE_ONLY | \ 623 DL_FLAG_INFERRED) 624 625 #define DL_ADD_VALID_FLAGS (DL_MANAGED_LINK_FLAGS | DL_FLAG_STATELESS | \ 626 DL_FLAG_PM_RUNTIME | DL_FLAG_RPM_ACTIVE) 627 628 /** 629 * device_link_add - Create a link between two devices. 630 * @consumer: Consumer end of the link. 631 * @supplier: Supplier end of the link. 632 * @flags: Link flags. 633 * 634 * The caller is responsible for the proper synchronization of the link creation 635 * with runtime PM. First, setting the DL_FLAG_PM_RUNTIME flag will cause the 636 * runtime PM framework to take the link into account. Second, if the 637 * DL_FLAG_RPM_ACTIVE flag is set in addition to it, the supplier devices will 638 * be forced into the active meta state and reference-counted upon the creation 639 * of the link. If DL_FLAG_PM_RUNTIME is not set, DL_FLAG_RPM_ACTIVE will be 640 * ignored. 641 * 642 * If DL_FLAG_STATELESS is set in @flags, the caller of this function is 643 * expected to release the link returned by it directly with the help of either 644 * device_link_del() or device_link_remove(). 645 * 646 * If that flag is not set, however, the caller of this function is handing the 647 * management of the link over to the driver core entirely and its return value 648 * can only be used to check whether or not the link is present. In that case, 649 * the DL_FLAG_AUTOREMOVE_CONSUMER and DL_FLAG_AUTOREMOVE_SUPPLIER device link 650 * flags can be used to indicate to the driver core when the link can be safely 651 * deleted. Namely, setting one of them in @flags indicates to the driver core 652 * that the link is not going to be used (by the given caller of this function) 653 * after unbinding the consumer or supplier driver, respectively, from its 654 * device, so the link can be deleted at that point. If none of them is set, 655 * the link will be maintained until one of the devices pointed to by it (either 656 * the consumer or the supplier) is unregistered. 657 * 658 * Also, if DL_FLAG_STATELESS, DL_FLAG_AUTOREMOVE_CONSUMER and 659 * DL_FLAG_AUTOREMOVE_SUPPLIER are not set in @flags (that is, a persistent 660 * managed device link is being added), the DL_FLAG_AUTOPROBE_CONSUMER flag can 661 * be used to request the driver core to automatically probe for a consumer 662 * driver after successfully binding a driver to the supplier device. 663 * 664 * The combination of DL_FLAG_STATELESS and one of DL_FLAG_AUTOREMOVE_CONSUMER, 665 * DL_FLAG_AUTOREMOVE_SUPPLIER, or DL_FLAG_AUTOPROBE_CONSUMER set in @flags at 666 * the same time is invalid and will cause NULL to be returned upfront. 667 * However, if a device link between the given @consumer and @supplier pair 668 * exists already when this function is called for them, the existing link will 669 * be returned regardless of its current type and status (the link's flags may 670 * be modified then). The caller of this function is then expected to treat 671 * the link as though it has just been created, so (in particular) if 672 * DL_FLAG_STATELESS was passed in @flags, the link needs to be released 673 * explicitly when not needed any more (as stated above). 674 * 675 * A side effect of the link creation is re-ordering of dpm_list and the 676 * devices_kset list by moving the consumer device and all devices depending 677 * on it to the ends of these lists (that does not happen to devices that have 678 * not been registered when this function is called). 679 * 680 * The supplier device is required to be registered when this function is called 681 * and NULL will be returned if that is not the case. The consumer device need 682 * not be registered, however. 683 */ 684 struct device_link *device_link_add(struct device *consumer, 685 struct device *supplier, u32 flags) 686 { 687 struct device_link *link; 688 689 if (!consumer || !supplier || consumer == supplier || 690 flags & ~DL_ADD_VALID_FLAGS || 691 (flags & DL_FLAG_STATELESS && flags & DL_MANAGED_LINK_FLAGS) || 692 (flags & DL_FLAG_SYNC_STATE_ONLY && 693 (flags & ~DL_FLAG_INFERRED) != DL_FLAG_SYNC_STATE_ONLY) || 694 (flags & DL_FLAG_AUTOPROBE_CONSUMER && 695 flags & (DL_FLAG_AUTOREMOVE_CONSUMER | 696 DL_FLAG_AUTOREMOVE_SUPPLIER))) 697 return NULL; 698 699 if (flags & DL_FLAG_PM_RUNTIME && flags & DL_FLAG_RPM_ACTIVE) { 700 if (pm_runtime_get_sync(supplier) < 0) { 701 pm_runtime_put_noidle(supplier); 702 return NULL; 703 } 704 } 705 706 if (!(flags & DL_FLAG_STATELESS)) 707 flags |= DL_FLAG_MANAGED; 708 709 device_links_write_lock(); 710 device_pm_lock(); 711 712 /* 713 * If the supplier has not been fully registered yet or there is a 714 * reverse (non-SYNC_STATE_ONLY) dependency between the consumer and 715 * the supplier already in the graph, return NULL. If the link is a 716 * SYNC_STATE_ONLY link, we don't check for reverse dependencies 717 * because it only affects sync_state() callbacks. 718 */ 719 if (!device_pm_initialized(supplier) 720 || (!(flags & DL_FLAG_SYNC_STATE_ONLY) && 721 device_is_dependent(consumer, supplier))) { 722 link = NULL; 723 goto out; 724 } 725 726 /* 727 * SYNC_STATE_ONLY links are useless once a consumer device has probed. 728 * So, only create it if the consumer hasn't probed yet. 729 */ 730 if (flags & DL_FLAG_SYNC_STATE_ONLY && 731 consumer->links.status != DL_DEV_NO_DRIVER && 732 consumer->links.status != DL_DEV_PROBING) { 733 link = NULL; 734 goto out; 735 } 736 737 /* 738 * DL_FLAG_AUTOREMOVE_SUPPLIER indicates that the link will be needed 739 * longer than for DL_FLAG_AUTOREMOVE_CONSUMER and setting them both 740 * together doesn't make sense, so prefer DL_FLAG_AUTOREMOVE_SUPPLIER. 741 */ 742 if (flags & DL_FLAG_AUTOREMOVE_SUPPLIER) 743 flags &= ~DL_FLAG_AUTOREMOVE_CONSUMER; 744 745 list_for_each_entry(link, &supplier->links.consumers, s_node) { 746 if (link->consumer != consumer) 747 continue; 748 749 if (link->flags & DL_FLAG_INFERRED && 750 !(flags & DL_FLAG_INFERRED)) 751 link->flags &= ~DL_FLAG_INFERRED; 752 753 if (flags & DL_FLAG_PM_RUNTIME) { 754 if (!(link->flags & DL_FLAG_PM_RUNTIME)) { 755 pm_runtime_new_link(consumer); 756 link->flags |= DL_FLAG_PM_RUNTIME; 757 } 758 if (flags & DL_FLAG_RPM_ACTIVE) 759 refcount_inc(&link->rpm_active); 760 } 761 762 if (flags & DL_FLAG_STATELESS) { 763 kref_get(&link->kref); 764 if (link->flags & DL_FLAG_SYNC_STATE_ONLY && 765 !(link->flags & DL_FLAG_STATELESS)) { 766 link->flags |= DL_FLAG_STATELESS; 767 goto reorder; 768 } else { 769 link->flags |= DL_FLAG_STATELESS; 770 goto out; 771 } 772 } 773 774 /* 775 * If the life time of the link following from the new flags is 776 * longer than indicated by the flags of the existing link, 777 * update the existing link to stay around longer. 778 */ 779 if (flags & DL_FLAG_AUTOREMOVE_SUPPLIER) { 780 if (link->flags & DL_FLAG_AUTOREMOVE_CONSUMER) { 781 link->flags &= ~DL_FLAG_AUTOREMOVE_CONSUMER; 782 link->flags |= DL_FLAG_AUTOREMOVE_SUPPLIER; 783 } 784 } else if (!(flags & DL_FLAG_AUTOREMOVE_CONSUMER)) { 785 link->flags &= ~(DL_FLAG_AUTOREMOVE_CONSUMER | 786 DL_FLAG_AUTOREMOVE_SUPPLIER); 787 } 788 if (!(link->flags & DL_FLAG_MANAGED)) { 789 kref_get(&link->kref); 790 link->flags |= DL_FLAG_MANAGED; 791 device_link_init_status(link, consumer, supplier); 792 } 793 if (link->flags & DL_FLAG_SYNC_STATE_ONLY && 794 !(flags & DL_FLAG_SYNC_STATE_ONLY)) { 795 link->flags &= ~DL_FLAG_SYNC_STATE_ONLY; 796 goto reorder; 797 } 798 799 goto out; 800 } 801 802 link = kzalloc(sizeof(*link), GFP_KERNEL); 803 if (!link) 804 goto out; 805 806 refcount_set(&link->rpm_active, 1); 807 808 get_device(supplier); 809 link->supplier = supplier; 810 INIT_LIST_HEAD(&link->s_node); 811 get_device(consumer); 812 link->consumer = consumer; 813 INIT_LIST_HEAD(&link->c_node); 814 link->flags = flags; 815 kref_init(&link->kref); 816 817 link->link_dev.class = &devlink_class; 818 device_set_pm_not_required(&link->link_dev); 819 dev_set_name(&link->link_dev, "%s:%s--%s:%s", 820 dev_bus_name(supplier), dev_name(supplier), 821 dev_bus_name(consumer), dev_name(consumer)); 822 if (device_register(&link->link_dev)) { 823 put_device(&link->link_dev); 824 link = NULL; 825 goto out; 826 } 827 828 if (flags & DL_FLAG_PM_RUNTIME) { 829 if (flags & DL_FLAG_RPM_ACTIVE) 830 refcount_inc(&link->rpm_active); 831 832 pm_runtime_new_link(consumer); 833 } 834 835 /* Determine the initial link state. */ 836 if (flags & DL_FLAG_STATELESS) 837 link->status = DL_STATE_NONE; 838 else 839 device_link_init_status(link, consumer, supplier); 840 841 /* 842 * Some callers expect the link creation during consumer driver probe to 843 * resume the supplier even without DL_FLAG_RPM_ACTIVE. 844 */ 845 if (link->status == DL_STATE_CONSUMER_PROBE && 846 flags & DL_FLAG_PM_RUNTIME) 847 pm_runtime_resume(supplier); 848 849 list_add_tail_rcu(&link->s_node, &supplier->links.consumers); 850 list_add_tail_rcu(&link->c_node, &consumer->links.suppliers); 851 852 if (flags & DL_FLAG_SYNC_STATE_ONLY) { 853 dev_dbg(consumer, 854 "Linked as a sync state only consumer to %s\n", 855 dev_name(supplier)); 856 goto out; 857 } 858 859 reorder: 860 /* 861 * Move the consumer and all of the devices depending on it to the end 862 * of dpm_list and the devices_kset list. 863 * 864 * It is necessary to hold dpm_list locked throughout all that or else 865 * we may end up suspending with a wrong ordering of it. 866 */ 867 device_reorder_to_tail(consumer, NULL); 868 869 dev_dbg(consumer, "Linked as a consumer to %s\n", dev_name(supplier)); 870 871 out: 872 device_pm_unlock(); 873 device_links_write_unlock(); 874 875 if ((flags & DL_FLAG_PM_RUNTIME && flags & DL_FLAG_RPM_ACTIVE) && !link) 876 pm_runtime_put(supplier); 877 878 return link; 879 } 880 EXPORT_SYMBOL_GPL(device_link_add); 881 882 static void __device_link_del(struct kref *kref) 883 { 884 struct device_link *link = container_of(kref, struct device_link, kref); 885 886 dev_dbg(link->consumer, "Dropping the link to %s\n", 887 dev_name(link->supplier)); 888 889 pm_runtime_drop_link(link); 890 891 device_link_remove_from_lists(link); 892 device_unregister(&link->link_dev); 893 } 894 895 static void device_link_put_kref(struct device_link *link) 896 { 897 if (link->flags & DL_FLAG_STATELESS) 898 kref_put(&link->kref, __device_link_del); 899 else if (!device_is_registered(link->consumer)) 900 __device_link_del(&link->kref); 901 else 902 WARN(1, "Unable to drop a managed device link reference\n"); 903 } 904 905 /** 906 * device_link_del - Delete a stateless link between two devices. 907 * @link: Device link to delete. 908 * 909 * The caller must ensure proper synchronization of this function with runtime 910 * PM. If the link was added multiple times, it needs to be deleted as often. 911 * Care is required for hotplugged devices: Their links are purged on removal 912 * and calling device_link_del() is then no longer allowed. 913 */ 914 void device_link_del(struct device_link *link) 915 { 916 device_links_write_lock(); 917 device_link_put_kref(link); 918 device_links_write_unlock(); 919 } 920 EXPORT_SYMBOL_GPL(device_link_del); 921 922 /** 923 * device_link_remove - Delete a stateless link between two devices. 924 * @consumer: Consumer end of the link. 925 * @supplier: Supplier end of the link. 926 * 927 * The caller must ensure proper synchronization of this function with runtime 928 * PM. 929 */ 930 void device_link_remove(void *consumer, struct device *supplier) 931 { 932 struct device_link *link; 933 934 if (WARN_ON(consumer == supplier)) 935 return; 936 937 device_links_write_lock(); 938 939 list_for_each_entry(link, &supplier->links.consumers, s_node) { 940 if (link->consumer == consumer) { 941 device_link_put_kref(link); 942 break; 943 } 944 } 945 946 device_links_write_unlock(); 947 } 948 EXPORT_SYMBOL_GPL(device_link_remove); 949 950 static void device_links_missing_supplier(struct device *dev) 951 { 952 struct device_link *link; 953 954 list_for_each_entry(link, &dev->links.suppliers, c_node) { 955 if (link->status != DL_STATE_CONSUMER_PROBE) 956 continue; 957 958 if (link->supplier->links.status == DL_DEV_DRIVER_BOUND) { 959 WRITE_ONCE(link->status, DL_STATE_AVAILABLE); 960 } else { 961 WARN_ON(!(link->flags & DL_FLAG_SYNC_STATE_ONLY)); 962 WRITE_ONCE(link->status, DL_STATE_DORMANT); 963 } 964 } 965 } 966 967 /** 968 * device_links_check_suppliers - Check presence of supplier drivers. 969 * @dev: Consumer device. 970 * 971 * Check links from this device to any suppliers. Walk the list of the device's 972 * links to suppliers and see if all of them are available. If not, simply 973 * return -EPROBE_DEFER. 974 * 975 * We need to guarantee that the supplier will not go away after the check has 976 * been positive here. It only can go away in __device_release_driver() and 977 * that function checks the device's links to consumers. This means we need to 978 * mark the link as "consumer probe in progress" to make the supplier removal 979 * wait for us to complete (or bad things may happen). 980 * 981 * Links without the DL_FLAG_MANAGED flag set are ignored. 982 */ 983 int device_links_check_suppliers(struct device *dev) 984 { 985 struct device_link *link; 986 int ret = 0; 987 struct fwnode_handle *sup_fw; 988 989 /* 990 * Device waiting for supplier to become available is not allowed to 991 * probe. 992 */ 993 mutex_lock(&fwnode_link_lock); 994 if (dev->fwnode && !list_empty(&dev->fwnode->suppliers) && 995 !fw_devlink_is_permissive()) { 996 sup_fw = list_first_entry(&dev->fwnode->suppliers, 997 struct fwnode_link, 998 c_hook)->supplier; 999 dev_err_probe(dev, -EPROBE_DEFER, "wait for supplier %pfwP\n", 1000 sup_fw); 1001 mutex_unlock(&fwnode_link_lock); 1002 return -EPROBE_DEFER; 1003 } 1004 mutex_unlock(&fwnode_link_lock); 1005 1006 device_links_write_lock(); 1007 1008 list_for_each_entry(link, &dev->links.suppliers, c_node) { 1009 if (!(link->flags & DL_FLAG_MANAGED)) 1010 continue; 1011 1012 if (link->status != DL_STATE_AVAILABLE && 1013 !(link->flags & DL_FLAG_SYNC_STATE_ONLY)) { 1014 device_links_missing_supplier(dev); 1015 dev_err_probe(dev, -EPROBE_DEFER, 1016 "supplier %s not ready\n", 1017 dev_name(link->supplier)); 1018 ret = -EPROBE_DEFER; 1019 break; 1020 } 1021 WRITE_ONCE(link->status, DL_STATE_CONSUMER_PROBE); 1022 } 1023 dev->links.status = DL_DEV_PROBING; 1024 1025 device_links_write_unlock(); 1026 return ret; 1027 } 1028 1029 /** 1030 * __device_links_queue_sync_state - Queue a device for sync_state() callback 1031 * @dev: Device to call sync_state() on 1032 * @list: List head to queue the @dev on 1033 * 1034 * Queues a device for a sync_state() callback when the device links write lock 1035 * isn't held. This allows the sync_state() execution flow to use device links 1036 * APIs. The caller must ensure this function is called with 1037 * device_links_write_lock() held. 1038 * 1039 * This function does a get_device() to make sure the device is not freed while 1040 * on this list. 1041 * 1042 * So the caller must also ensure that device_links_flush_sync_list() is called 1043 * as soon as the caller releases device_links_write_lock(). This is necessary 1044 * to make sure the sync_state() is called in a timely fashion and the 1045 * put_device() is called on this device. 1046 */ 1047 static void __device_links_queue_sync_state(struct device *dev, 1048 struct list_head *list) 1049 { 1050 struct device_link *link; 1051 1052 if (!dev_has_sync_state(dev)) 1053 return; 1054 if (dev->state_synced) 1055 return; 1056 1057 list_for_each_entry(link, &dev->links.consumers, s_node) { 1058 if (!(link->flags & DL_FLAG_MANAGED)) 1059 continue; 1060 if (link->status != DL_STATE_ACTIVE) 1061 return; 1062 } 1063 1064 /* 1065 * Set the flag here to avoid adding the same device to a list more 1066 * than once. This can happen if new consumers get added to the device 1067 * and probed before the list is flushed. 1068 */ 1069 dev->state_synced = true; 1070 1071 if (WARN_ON(!list_empty(&dev->links.defer_sync))) 1072 return; 1073 1074 get_device(dev); 1075 list_add_tail(&dev->links.defer_sync, list); 1076 } 1077 1078 /** 1079 * device_links_flush_sync_list - Call sync_state() on a list of devices 1080 * @list: List of devices to call sync_state() on 1081 * @dont_lock_dev: Device for which lock is already held by the caller 1082 * 1083 * Calls sync_state() on all the devices that have been queued for it. This 1084 * function is used in conjunction with __device_links_queue_sync_state(). The 1085 * @dont_lock_dev parameter is useful when this function is called from a 1086 * context where a device lock is already held. 1087 */ 1088 static void device_links_flush_sync_list(struct list_head *list, 1089 struct device *dont_lock_dev) 1090 { 1091 struct device *dev, *tmp; 1092 1093 list_for_each_entry_safe(dev, tmp, list, links.defer_sync) { 1094 list_del_init(&dev->links.defer_sync); 1095 1096 if (dev != dont_lock_dev) 1097 device_lock(dev); 1098 1099 if (dev->bus->sync_state) 1100 dev->bus->sync_state(dev); 1101 else if (dev->driver && dev->driver->sync_state) 1102 dev->driver->sync_state(dev); 1103 1104 if (dev != dont_lock_dev) 1105 device_unlock(dev); 1106 1107 put_device(dev); 1108 } 1109 } 1110 1111 void device_links_supplier_sync_state_pause(void) 1112 { 1113 device_links_write_lock(); 1114 defer_sync_state_count++; 1115 device_links_write_unlock(); 1116 } 1117 1118 void device_links_supplier_sync_state_resume(void) 1119 { 1120 struct device *dev, *tmp; 1121 LIST_HEAD(sync_list); 1122 1123 device_links_write_lock(); 1124 if (!defer_sync_state_count) { 1125 WARN(true, "Unmatched sync_state pause/resume!"); 1126 goto out; 1127 } 1128 defer_sync_state_count--; 1129 if (defer_sync_state_count) 1130 goto out; 1131 1132 list_for_each_entry_safe(dev, tmp, &deferred_sync, links.defer_sync) { 1133 /* 1134 * Delete from deferred_sync list before queuing it to 1135 * sync_list because defer_sync is used for both lists. 1136 */ 1137 list_del_init(&dev->links.defer_sync); 1138 __device_links_queue_sync_state(dev, &sync_list); 1139 } 1140 out: 1141 device_links_write_unlock(); 1142 1143 device_links_flush_sync_list(&sync_list, NULL); 1144 } 1145 1146 static int sync_state_resume_initcall(void) 1147 { 1148 device_links_supplier_sync_state_resume(); 1149 return 0; 1150 } 1151 late_initcall(sync_state_resume_initcall); 1152 1153 static void __device_links_supplier_defer_sync(struct device *sup) 1154 { 1155 if (list_empty(&sup->links.defer_sync) && dev_has_sync_state(sup)) 1156 list_add_tail(&sup->links.defer_sync, &deferred_sync); 1157 } 1158 1159 static void device_link_drop_managed(struct device_link *link) 1160 { 1161 link->flags &= ~DL_FLAG_MANAGED; 1162 WRITE_ONCE(link->status, DL_STATE_NONE); 1163 kref_put(&link->kref, __device_link_del); 1164 } 1165 1166 static ssize_t waiting_for_supplier_show(struct device *dev, 1167 struct device_attribute *attr, 1168 char *buf) 1169 { 1170 bool val; 1171 1172 device_lock(dev); 1173 val = !list_empty(&dev->fwnode->suppliers); 1174 device_unlock(dev); 1175 return sysfs_emit(buf, "%u\n", val); 1176 } 1177 static DEVICE_ATTR_RO(waiting_for_supplier); 1178 1179 /** 1180 * device_links_force_bind - Prepares device to be force bound 1181 * @dev: Consumer device. 1182 * 1183 * device_bind_driver() force binds a device to a driver without calling any 1184 * driver probe functions. So the consumer really isn't going to wait for any 1185 * supplier before it's bound to the driver. We still want the device link 1186 * states to be sensible when this happens. 1187 * 1188 * In preparation for device_bind_driver(), this function goes through each 1189 * supplier device links and checks if the supplier is bound. If it is, then 1190 * the device link status is set to CONSUMER_PROBE. Otherwise, the device link 1191 * is dropped. Links without the DL_FLAG_MANAGED flag set are ignored. 1192 */ 1193 void device_links_force_bind(struct device *dev) 1194 { 1195 struct device_link *link, *ln; 1196 1197 device_links_write_lock(); 1198 1199 list_for_each_entry_safe(link, ln, &dev->links.suppliers, c_node) { 1200 if (!(link->flags & DL_FLAG_MANAGED)) 1201 continue; 1202 1203 if (link->status != DL_STATE_AVAILABLE) { 1204 device_link_drop_managed(link); 1205 continue; 1206 } 1207 WRITE_ONCE(link->status, DL_STATE_CONSUMER_PROBE); 1208 } 1209 dev->links.status = DL_DEV_PROBING; 1210 1211 device_links_write_unlock(); 1212 } 1213 1214 /** 1215 * device_links_driver_bound - Update device links after probing its driver. 1216 * @dev: Device to update the links for. 1217 * 1218 * The probe has been successful, so update links from this device to any 1219 * consumers by changing their status to "available". 1220 * 1221 * Also change the status of @dev's links to suppliers to "active". 1222 * 1223 * Links without the DL_FLAG_MANAGED flag set are ignored. 1224 */ 1225 void device_links_driver_bound(struct device *dev) 1226 { 1227 struct device_link *link, *ln; 1228 LIST_HEAD(sync_list); 1229 1230 /* 1231 * If a device binds successfully, it's expected to have created all 1232 * the device links it needs to or make new device links as it needs 1233 * them. So, fw_devlink no longer needs to create device links to any 1234 * of the device's suppliers. 1235 * 1236 * Also, if a child firmware node of this bound device is not added as 1237 * a device by now, assume it is never going to be added and make sure 1238 * other devices don't defer probe indefinitely by waiting for such a 1239 * child device. 1240 */ 1241 if (dev->fwnode && dev->fwnode->dev == dev) { 1242 struct fwnode_handle *child; 1243 fwnode_links_purge_suppliers(dev->fwnode); 1244 fwnode_for_each_available_child_node(dev->fwnode, child) 1245 fw_devlink_purge_absent_suppliers(child); 1246 } 1247 device_remove_file(dev, &dev_attr_waiting_for_supplier); 1248 1249 device_links_write_lock(); 1250 1251 list_for_each_entry(link, &dev->links.consumers, s_node) { 1252 if (!(link->flags & DL_FLAG_MANAGED)) 1253 continue; 1254 1255 /* 1256 * Links created during consumer probe may be in the "consumer 1257 * probe" state to start with if the supplier is still probing 1258 * when they are created and they may become "active" if the 1259 * consumer probe returns first. Skip them here. 1260 */ 1261 if (link->status == DL_STATE_CONSUMER_PROBE || 1262 link->status == DL_STATE_ACTIVE) 1263 continue; 1264 1265 WARN_ON(link->status != DL_STATE_DORMANT); 1266 WRITE_ONCE(link->status, DL_STATE_AVAILABLE); 1267 1268 if (link->flags & DL_FLAG_AUTOPROBE_CONSUMER) 1269 driver_deferred_probe_add(link->consumer); 1270 } 1271 1272 if (defer_sync_state_count) 1273 __device_links_supplier_defer_sync(dev); 1274 else 1275 __device_links_queue_sync_state(dev, &sync_list); 1276 1277 list_for_each_entry_safe(link, ln, &dev->links.suppliers, c_node) { 1278 struct device *supplier; 1279 1280 if (!(link->flags & DL_FLAG_MANAGED)) 1281 continue; 1282 1283 supplier = link->supplier; 1284 if (link->flags & DL_FLAG_SYNC_STATE_ONLY) { 1285 /* 1286 * When DL_FLAG_SYNC_STATE_ONLY is set, it means no 1287 * other DL_MANAGED_LINK_FLAGS have been set. So, it's 1288 * save to drop the managed link completely. 1289 */ 1290 device_link_drop_managed(link); 1291 } else { 1292 WARN_ON(link->status != DL_STATE_CONSUMER_PROBE); 1293 WRITE_ONCE(link->status, DL_STATE_ACTIVE); 1294 } 1295 1296 /* 1297 * This needs to be done even for the deleted 1298 * DL_FLAG_SYNC_STATE_ONLY device link in case it was the last 1299 * device link that was preventing the supplier from getting a 1300 * sync_state() call. 1301 */ 1302 if (defer_sync_state_count) 1303 __device_links_supplier_defer_sync(supplier); 1304 else 1305 __device_links_queue_sync_state(supplier, &sync_list); 1306 } 1307 1308 dev->links.status = DL_DEV_DRIVER_BOUND; 1309 1310 device_links_write_unlock(); 1311 1312 device_links_flush_sync_list(&sync_list, dev); 1313 } 1314 1315 /** 1316 * __device_links_no_driver - Update links of a device without a driver. 1317 * @dev: Device without a drvier. 1318 * 1319 * Delete all non-persistent links from this device to any suppliers. 1320 * 1321 * Persistent links stay around, but their status is changed to "available", 1322 * unless they already are in the "supplier unbind in progress" state in which 1323 * case they need not be updated. 1324 * 1325 * Links without the DL_FLAG_MANAGED flag set are ignored. 1326 */ 1327 static void __device_links_no_driver(struct device *dev) 1328 { 1329 struct device_link *link, *ln; 1330 1331 list_for_each_entry_safe_reverse(link, ln, &dev->links.suppliers, c_node) { 1332 if (!(link->flags & DL_FLAG_MANAGED)) 1333 continue; 1334 1335 if (link->flags & DL_FLAG_AUTOREMOVE_CONSUMER) { 1336 device_link_drop_managed(link); 1337 continue; 1338 } 1339 1340 if (link->status != DL_STATE_CONSUMER_PROBE && 1341 link->status != DL_STATE_ACTIVE) 1342 continue; 1343 1344 if (link->supplier->links.status == DL_DEV_DRIVER_BOUND) { 1345 WRITE_ONCE(link->status, DL_STATE_AVAILABLE); 1346 } else { 1347 WARN_ON(!(link->flags & DL_FLAG_SYNC_STATE_ONLY)); 1348 WRITE_ONCE(link->status, DL_STATE_DORMANT); 1349 } 1350 } 1351 1352 dev->links.status = DL_DEV_NO_DRIVER; 1353 } 1354 1355 /** 1356 * device_links_no_driver - Update links after failing driver probe. 1357 * @dev: Device whose driver has just failed to probe. 1358 * 1359 * Clean up leftover links to consumers for @dev and invoke 1360 * %__device_links_no_driver() to update links to suppliers for it as 1361 * appropriate. 1362 * 1363 * Links without the DL_FLAG_MANAGED flag set are ignored. 1364 */ 1365 void device_links_no_driver(struct device *dev) 1366 { 1367 struct device_link *link; 1368 1369 device_links_write_lock(); 1370 1371 list_for_each_entry(link, &dev->links.consumers, s_node) { 1372 if (!(link->flags & DL_FLAG_MANAGED)) 1373 continue; 1374 1375 /* 1376 * The probe has failed, so if the status of the link is 1377 * "consumer probe" or "active", it must have been added by 1378 * a probing consumer while this device was still probing. 1379 * Change its state to "dormant", as it represents a valid 1380 * relationship, but it is not functionally meaningful. 1381 */ 1382 if (link->status == DL_STATE_CONSUMER_PROBE || 1383 link->status == DL_STATE_ACTIVE) 1384 WRITE_ONCE(link->status, DL_STATE_DORMANT); 1385 } 1386 1387 __device_links_no_driver(dev); 1388 1389 device_links_write_unlock(); 1390 } 1391 1392 /** 1393 * device_links_driver_cleanup - Update links after driver removal. 1394 * @dev: Device whose driver has just gone away. 1395 * 1396 * Update links to consumers for @dev by changing their status to "dormant" and 1397 * invoke %__device_links_no_driver() to update links to suppliers for it as 1398 * appropriate. 1399 * 1400 * Links without the DL_FLAG_MANAGED flag set are ignored. 1401 */ 1402 void device_links_driver_cleanup(struct device *dev) 1403 { 1404 struct device_link *link, *ln; 1405 1406 device_links_write_lock(); 1407 1408 list_for_each_entry_safe(link, ln, &dev->links.consumers, s_node) { 1409 if (!(link->flags & DL_FLAG_MANAGED)) 1410 continue; 1411 1412 WARN_ON(link->flags & DL_FLAG_AUTOREMOVE_CONSUMER); 1413 WARN_ON(link->status != DL_STATE_SUPPLIER_UNBIND); 1414 1415 /* 1416 * autoremove the links between this @dev and its consumer 1417 * devices that are not active, i.e. where the link state 1418 * has moved to DL_STATE_SUPPLIER_UNBIND. 1419 */ 1420 if (link->status == DL_STATE_SUPPLIER_UNBIND && 1421 link->flags & DL_FLAG_AUTOREMOVE_SUPPLIER) 1422 device_link_drop_managed(link); 1423 1424 WRITE_ONCE(link->status, DL_STATE_DORMANT); 1425 } 1426 1427 list_del_init(&dev->links.defer_sync); 1428 __device_links_no_driver(dev); 1429 1430 device_links_write_unlock(); 1431 } 1432 1433 /** 1434 * device_links_busy - Check if there are any busy links to consumers. 1435 * @dev: Device to check. 1436 * 1437 * Check each consumer of the device and return 'true' if its link's status 1438 * is one of "consumer probe" or "active" (meaning that the given consumer is 1439 * probing right now or its driver is present). Otherwise, change the link 1440 * state to "supplier unbind" to prevent the consumer from being probed 1441 * successfully going forward. 1442 * 1443 * Return 'false' if there are no probing or active consumers. 1444 * 1445 * Links without the DL_FLAG_MANAGED flag set are ignored. 1446 */ 1447 bool device_links_busy(struct device *dev) 1448 { 1449 struct device_link *link; 1450 bool ret = false; 1451 1452 device_links_write_lock(); 1453 1454 list_for_each_entry(link, &dev->links.consumers, s_node) { 1455 if (!(link->flags & DL_FLAG_MANAGED)) 1456 continue; 1457 1458 if (link->status == DL_STATE_CONSUMER_PROBE 1459 || link->status == DL_STATE_ACTIVE) { 1460 ret = true; 1461 break; 1462 } 1463 WRITE_ONCE(link->status, DL_STATE_SUPPLIER_UNBIND); 1464 } 1465 1466 dev->links.status = DL_DEV_UNBINDING; 1467 1468 device_links_write_unlock(); 1469 return ret; 1470 } 1471 1472 /** 1473 * device_links_unbind_consumers - Force unbind consumers of the given device. 1474 * @dev: Device to unbind the consumers of. 1475 * 1476 * Walk the list of links to consumers for @dev and if any of them is in the 1477 * "consumer probe" state, wait for all device probes in progress to complete 1478 * and start over. 1479 * 1480 * If that's not the case, change the status of the link to "supplier unbind" 1481 * and check if the link was in the "active" state. If so, force the consumer 1482 * driver to unbind and start over (the consumer will not re-probe as we have 1483 * changed the state of the link already). 1484 * 1485 * Links without the DL_FLAG_MANAGED flag set are ignored. 1486 */ 1487 void device_links_unbind_consumers(struct device *dev) 1488 { 1489 struct device_link *link; 1490 1491 start: 1492 device_links_write_lock(); 1493 1494 list_for_each_entry(link, &dev->links.consumers, s_node) { 1495 enum device_link_state status; 1496 1497 if (!(link->flags & DL_FLAG_MANAGED) || 1498 link->flags & DL_FLAG_SYNC_STATE_ONLY) 1499 continue; 1500 1501 status = link->status; 1502 if (status == DL_STATE_CONSUMER_PROBE) { 1503 device_links_write_unlock(); 1504 1505 wait_for_device_probe(); 1506 goto start; 1507 } 1508 WRITE_ONCE(link->status, DL_STATE_SUPPLIER_UNBIND); 1509 if (status == DL_STATE_ACTIVE) { 1510 struct device *consumer = link->consumer; 1511 1512 get_device(consumer); 1513 1514 device_links_write_unlock(); 1515 1516 device_release_driver_internal(consumer, NULL, 1517 consumer->parent); 1518 put_device(consumer); 1519 goto start; 1520 } 1521 } 1522 1523 device_links_write_unlock(); 1524 } 1525 1526 /** 1527 * device_links_purge - Delete existing links to other devices. 1528 * @dev: Target device. 1529 */ 1530 static void device_links_purge(struct device *dev) 1531 { 1532 struct device_link *link, *ln; 1533 1534 if (dev->class == &devlink_class) 1535 return; 1536 1537 /* 1538 * Delete all of the remaining links from this device to any other 1539 * devices (either consumers or suppliers). 1540 */ 1541 device_links_write_lock(); 1542 1543 list_for_each_entry_safe_reverse(link, ln, &dev->links.suppliers, c_node) { 1544 WARN_ON(link->status == DL_STATE_ACTIVE); 1545 __device_link_del(&link->kref); 1546 } 1547 1548 list_for_each_entry_safe_reverse(link, ln, &dev->links.consumers, s_node) { 1549 WARN_ON(link->status != DL_STATE_DORMANT && 1550 link->status != DL_STATE_NONE); 1551 __device_link_del(&link->kref); 1552 } 1553 1554 device_links_write_unlock(); 1555 } 1556 1557 #define FW_DEVLINK_FLAGS_PERMISSIVE (DL_FLAG_INFERRED | \ 1558 DL_FLAG_SYNC_STATE_ONLY) 1559 #define FW_DEVLINK_FLAGS_ON (DL_FLAG_INFERRED | \ 1560 DL_FLAG_AUTOPROBE_CONSUMER) 1561 #define FW_DEVLINK_FLAGS_RPM (FW_DEVLINK_FLAGS_ON | \ 1562 DL_FLAG_PM_RUNTIME) 1563 1564 static u32 fw_devlink_flags = FW_DEVLINK_FLAGS_ON; 1565 static int __init fw_devlink_setup(char *arg) 1566 { 1567 if (!arg) 1568 return -EINVAL; 1569 1570 if (strcmp(arg, "off") == 0) { 1571 fw_devlink_flags = 0; 1572 } else if (strcmp(arg, "permissive") == 0) { 1573 fw_devlink_flags = FW_DEVLINK_FLAGS_PERMISSIVE; 1574 } else if (strcmp(arg, "on") == 0) { 1575 fw_devlink_flags = FW_DEVLINK_FLAGS_ON; 1576 } else if (strcmp(arg, "rpm") == 0) { 1577 fw_devlink_flags = FW_DEVLINK_FLAGS_RPM; 1578 } 1579 return 0; 1580 } 1581 early_param("fw_devlink", fw_devlink_setup); 1582 1583 static bool fw_devlink_strict; 1584 static int __init fw_devlink_strict_setup(char *arg) 1585 { 1586 return strtobool(arg, &fw_devlink_strict); 1587 } 1588 early_param("fw_devlink.strict", fw_devlink_strict_setup); 1589 1590 u32 fw_devlink_get_flags(void) 1591 { 1592 return fw_devlink_flags; 1593 } 1594 1595 static bool fw_devlink_is_permissive(void) 1596 { 1597 return fw_devlink_flags == FW_DEVLINK_FLAGS_PERMISSIVE; 1598 } 1599 1600 bool fw_devlink_is_strict(void) 1601 { 1602 return fw_devlink_strict && !fw_devlink_is_permissive(); 1603 } 1604 1605 static void fw_devlink_parse_fwnode(struct fwnode_handle *fwnode) 1606 { 1607 if (fwnode->flags & FWNODE_FLAG_LINKS_ADDED) 1608 return; 1609 1610 fwnode_call_int_op(fwnode, add_links); 1611 fwnode->flags |= FWNODE_FLAG_LINKS_ADDED; 1612 } 1613 1614 static void fw_devlink_parse_fwtree(struct fwnode_handle *fwnode) 1615 { 1616 struct fwnode_handle *child = NULL; 1617 1618 fw_devlink_parse_fwnode(fwnode); 1619 1620 while ((child = fwnode_get_next_available_child_node(fwnode, child))) 1621 fw_devlink_parse_fwtree(child); 1622 } 1623 1624 static void fw_devlink_relax_link(struct device_link *link) 1625 { 1626 if (!(link->flags & DL_FLAG_INFERRED)) 1627 return; 1628 1629 if (link->flags == (DL_FLAG_MANAGED | FW_DEVLINK_FLAGS_PERMISSIVE)) 1630 return; 1631 1632 pm_runtime_drop_link(link); 1633 link->flags = DL_FLAG_MANAGED | FW_DEVLINK_FLAGS_PERMISSIVE; 1634 dev_dbg(link->consumer, "Relaxing link with %s\n", 1635 dev_name(link->supplier)); 1636 } 1637 1638 static int fw_devlink_no_driver(struct device *dev, void *data) 1639 { 1640 struct device_link *link = to_devlink(dev); 1641 1642 if (!link->supplier->can_match) 1643 fw_devlink_relax_link(link); 1644 1645 return 0; 1646 } 1647 1648 void fw_devlink_drivers_done(void) 1649 { 1650 fw_devlink_drv_reg_done = true; 1651 device_links_write_lock(); 1652 class_for_each_device(&devlink_class, NULL, NULL, 1653 fw_devlink_no_driver); 1654 device_links_write_unlock(); 1655 } 1656 1657 static void fw_devlink_unblock_consumers(struct device *dev) 1658 { 1659 struct device_link *link; 1660 1661 if (!fw_devlink_flags || fw_devlink_is_permissive()) 1662 return; 1663 1664 device_links_write_lock(); 1665 list_for_each_entry(link, &dev->links.consumers, s_node) 1666 fw_devlink_relax_link(link); 1667 device_links_write_unlock(); 1668 } 1669 1670 /** 1671 * fw_devlink_relax_cycle - Convert cyclic links to SYNC_STATE_ONLY links 1672 * @con: Device to check dependencies for. 1673 * @sup: Device to check against. 1674 * 1675 * Check if @sup depends on @con or any device dependent on it (its child or 1676 * its consumer etc). When such a cyclic dependency is found, convert all 1677 * device links created solely by fw_devlink into SYNC_STATE_ONLY device links. 1678 * This is the equivalent of doing fw_devlink=permissive just between the 1679 * devices in the cycle. We need to do this because, at this point, fw_devlink 1680 * can't tell which of these dependencies is not a real dependency. 1681 * 1682 * Return 1 if a cycle is found. Otherwise, return 0. 1683 */ 1684 static int fw_devlink_relax_cycle(struct device *con, void *sup) 1685 { 1686 struct device_link *link; 1687 int ret; 1688 1689 if (con == sup) 1690 return 1; 1691 1692 ret = device_for_each_child(con, sup, fw_devlink_relax_cycle); 1693 if (ret) 1694 return ret; 1695 1696 list_for_each_entry(link, &con->links.consumers, s_node) { 1697 if ((link->flags & ~DL_FLAG_INFERRED) == 1698 (DL_FLAG_SYNC_STATE_ONLY | DL_FLAG_MANAGED)) 1699 continue; 1700 1701 if (!fw_devlink_relax_cycle(link->consumer, sup)) 1702 continue; 1703 1704 ret = 1; 1705 1706 fw_devlink_relax_link(link); 1707 } 1708 return ret; 1709 } 1710 1711 /** 1712 * fw_devlink_create_devlink - Create a device link from a consumer to fwnode 1713 * @con: consumer device for the device link 1714 * @sup_handle: fwnode handle of supplier 1715 * @flags: devlink flags 1716 * 1717 * This function will try to create a device link between the consumer device 1718 * @con and the supplier device represented by @sup_handle. 1719 * 1720 * The supplier has to be provided as a fwnode because incorrect cycles in 1721 * fwnode links can sometimes cause the supplier device to never be created. 1722 * This function detects such cases and returns an error if it cannot create a 1723 * device link from the consumer to a missing supplier. 1724 * 1725 * Returns, 1726 * 0 on successfully creating a device link 1727 * -EINVAL if the device link cannot be created as expected 1728 * -EAGAIN if the device link cannot be created right now, but it may be 1729 * possible to do that in the future 1730 */ 1731 static int fw_devlink_create_devlink(struct device *con, 1732 struct fwnode_handle *sup_handle, u32 flags) 1733 { 1734 struct device *sup_dev; 1735 int ret = 0; 1736 1737 /* 1738 * In some cases, a device P might also be a supplier to its child node 1739 * C. However, this would defer the probe of C until the probe of P 1740 * completes successfully. This is perfectly fine in the device driver 1741 * model. device_add() doesn't guarantee probe completion of the device 1742 * by the time it returns. 1743 * 1744 * However, there are a few drivers that assume C will finish probing 1745 * as soon as it's added and before P finishes probing. So, we provide 1746 * a flag to let fw_devlink know not to delay the probe of C until the 1747 * probe of P completes successfully. 1748 * 1749 * When such a flag is set, we can't create device links where P is the 1750 * supplier of C as that would delay the probe of C. 1751 */ 1752 if (sup_handle->flags & FWNODE_FLAG_NEEDS_CHILD_BOUND_ON_ADD && 1753 fwnode_is_ancestor_of(sup_handle, con->fwnode)) 1754 return -EINVAL; 1755 1756 sup_dev = get_dev_from_fwnode(sup_handle); 1757 if (sup_dev) { 1758 /* 1759 * If it's one of those drivers that don't actually bind to 1760 * their device using driver core, then don't wait on this 1761 * supplier device indefinitely. 1762 */ 1763 if (sup_dev->links.status == DL_DEV_NO_DRIVER && 1764 sup_handle->flags & FWNODE_FLAG_INITIALIZED) { 1765 ret = -EINVAL; 1766 goto out; 1767 } 1768 1769 /* 1770 * If this fails, it is due to cycles in device links. Just 1771 * give up on this link and treat it as invalid. 1772 */ 1773 if (!device_link_add(con, sup_dev, flags) && 1774 !(flags & DL_FLAG_SYNC_STATE_ONLY)) { 1775 dev_info(con, "Fixing up cyclic dependency with %s\n", 1776 dev_name(sup_dev)); 1777 device_links_write_lock(); 1778 fw_devlink_relax_cycle(con, sup_dev); 1779 device_links_write_unlock(); 1780 device_link_add(con, sup_dev, 1781 FW_DEVLINK_FLAGS_PERMISSIVE); 1782 ret = -EINVAL; 1783 } 1784 1785 goto out; 1786 } 1787 1788 /* Supplier that's already initialized without a struct device. */ 1789 if (sup_handle->flags & FWNODE_FLAG_INITIALIZED) 1790 return -EINVAL; 1791 1792 /* 1793 * DL_FLAG_SYNC_STATE_ONLY doesn't block probing and supports 1794 * cycles. So cycle detection isn't necessary and shouldn't be 1795 * done. 1796 */ 1797 if (flags & DL_FLAG_SYNC_STATE_ONLY) 1798 return -EAGAIN; 1799 1800 /* 1801 * If we can't find the supplier device from its fwnode, it might be 1802 * due to a cyclic dependency between fwnodes. Some of these cycles can 1803 * be broken by applying logic. Check for these types of cycles and 1804 * break them so that devices in the cycle probe properly. 1805 * 1806 * If the supplier's parent is dependent on the consumer, then the 1807 * consumer and supplier have a cyclic dependency. Since fw_devlink 1808 * can't tell which of the inferred dependencies are incorrect, don't 1809 * enforce probe ordering between any of the devices in this cyclic 1810 * dependency. Do this by relaxing all the fw_devlink device links in 1811 * this cycle and by treating the fwnode link between the consumer and 1812 * the supplier as an invalid dependency. 1813 */ 1814 sup_dev = fwnode_get_next_parent_dev(sup_handle); 1815 if (sup_dev && device_is_dependent(con, sup_dev)) { 1816 dev_info(con, "Fixing up cyclic dependency with %pfwP (%s)\n", 1817 sup_handle, dev_name(sup_dev)); 1818 device_links_write_lock(); 1819 fw_devlink_relax_cycle(con, sup_dev); 1820 device_links_write_unlock(); 1821 ret = -EINVAL; 1822 } else { 1823 /* 1824 * Can't check for cycles or no cycles. So let's try 1825 * again later. 1826 */ 1827 ret = -EAGAIN; 1828 } 1829 1830 out: 1831 put_device(sup_dev); 1832 return ret; 1833 } 1834 1835 /** 1836 * __fw_devlink_link_to_consumers - Create device links to consumers of a device 1837 * @dev: Device that needs to be linked to its consumers 1838 * 1839 * This function looks at all the consumer fwnodes of @dev and creates device 1840 * links between the consumer device and @dev (supplier). 1841 * 1842 * If the consumer device has not been added yet, then this function creates a 1843 * SYNC_STATE_ONLY link between @dev (supplier) and the closest ancestor device 1844 * of the consumer fwnode. This is necessary to make sure @dev doesn't get a 1845 * sync_state() callback before the real consumer device gets to be added and 1846 * then probed. 1847 * 1848 * Once device links are created from the real consumer to @dev (supplier), the 1849 * fwnode links are deleted. 1850 */ 1851 static void __fw_devlink_link_to_consumers(struct device *dev) 1852 { 1853 struct fwnode_handle *fwnode = dev->fwnode; 1854 struct fwnode_link *link, *tmp; 1855 1856 list_for_each_entry_safe(link, tmp, &fwnode->consumers, s_hook) { 1857 u32 dl_flags = fw_devlink_get_flags(); 1858 struct device *con_dev; 1859 bool own_link = true; 1860 int ret; 1861 1862 con_dev = get_dev_from_fwnode(link->consumer); 1863 /* 1864 * If consumer device is not available yet, make a "proxy" 1865 * SYNC_STATE_ONLY link from the consumer's parent device to 1866 * the supplier device. This is necessary to make sure the 1867 * supplier doesn't get a sync_state() callback before the real 1868 * consumer can create a device link to the supplier. 1869 * 1870 * This proxy link step is needed to handle the case where the 1871 * consumer's parent device is added before the supplier. 1872 */ 1873 if (!con_dev) { 1874 con_dev = fwnode_get_next_parent_dev(link->consumer); 1875 /* 1876 * However, if the consumer's parent device is also the 1877 * parent of the supplier, don't create a 1878 * consumer-supplier link from the parent to its child 1879 * device. Such a dependency is impossible. 1880 */ 1881 if (con_dev && 1882 fwnode_is_ancestor_of(con_dev->fwnode, fwnode)) { 1883 put_device(con_dev); 1884 con_dev = NULL; 1885 } else { 1886 own_link = false; 1887 dl_flags = FW_DEVLINK_FLAGS_PERMISSIVE; 1888 } 1889 } 1890 1891 if (!con_dev) 1892 continue; 1893 1894 ret = fw_devlink_create_devlink(con_dev, fwnode, dl_flags); 1895 put_device(con_dev); 1896 if (!own_link || ret == -EAGAIN) 1897 continue; 1898 1899 __fwnode_link_del(link); 1900 } 1901 } 1902 1903 /** 1904 * __fw_devlink_link_to_suppliers - Create device links to suppliers of a device 1905 * @dev: The consumer device that needs to be linked to its suppliers 1906 * @fwnode: Root of the fwnode tree that is used to create device links 1907 * 1908 * This function looks at all the supplier fwnodes of fwnode tree rooted at 1909 * @fwnode and creates device links between @dev (consumer) and all the 1910 * supplier devices of the entire fwnode tree at @fwnode. 1911 * 1912 * The function creates normal (non-SYNC_STATE_ONLY) device links between @dev 1913 * and the real suppliers of @dev. Once these device links are created, the 1914 * fwnode links are deleted. When such device links are successfully created, 1915 * this function is called recursively on those supplier devices. This is 1916 * needed to detect and break some invalid cycles in fwnode links. See 1917 * fw_devlink_create_devlink() for more details. 1918 * 1919 * In addition, it also looks at all the suppliers of the entire fwnode tree 1920 * because some of the child devices of @dev that have not been added yet 1921 * (because @dev hasn't probed) might already have their suppliers added to 1922 * driver core. So, this function creates SYNC_STATE_ONLY device links between 1923 * @dev (consumer) and these suppliers to make sure they don't execute their 1924 * sync_state() callbacks before these child devices have a chance to create 1925 * their device links. The fwnode links that correspond to the child devices 1926 * aren't delete because they are needed later to create the device links 1927 * between the real consumer and supplier devices. 1928 */ 1929 static void __fw_devlink_link_to_suppliers(struct device *dev, 1930 struct fwnode_handle *fwnode) 1931 { 1932 bool own_link = (dev->fwnode == fwnode); 1933 struct fwnode_link *link, *tmp; 1934 struct fwnode_handle *child = NULL; 1935 u32 dl_flags; 1936 1937 if (own_link) 1938 dl_flags = fw_devlink_get_flags(); 1939 else 1940 dl_flags = FW_DEVLINK_FLAGS_PERMISSIVE; 1941 1942 list_for_each_entry_safe(link, tmp, &fwnode->suppliers, c_hook) { 1943 int ret; 1944 struct device *sup_dev; 1945 struct fwnode_handle *sup = link->supplier; 1946 1947 ret = fw_devlink_create_devlink(dev, sup, dl_flags); 1948 if (!own_link || ret == -EAGAIN) 1949 continue; 1950 1951 __fwnode_link_del(link); 1952 1953 /* If no device link was created, nothing more to do. */ 1954 if (ret) 1955 continue; 1956 1957 /* 1958 * If a device link was successfully created to a supplier, we 1959 * now need to try and link the supplier to all its suppliers. 1960 * 1961 * This is needed to detect and delete false dependencies in 1962 * fwnode links that haven't been converted to a device link 1963 * yet. See comments in fw_devlink_create_devlink() for more 1964 * details on the false dependency. 1965 * 1966 * Without deleting these false dependencies, some devices will 1967 * never probe because they'll keep waiting for their false 1968 * dependency fwnode links to be converted to device links. 1969 */ 1970 sup_dev = get_dev_from_fwnode(sup); 1971 __fw_devlink_link_to_suppliers(sup_dev, sup_dev->fwnode); 1972 put_device(sup_dev); 1973 } 1974 1975 /* 1976 * Make "proxy" SYNC_STATE_ONLY device links to represent the needs of 1977 * all the descendants. This proxy link step is needed to handle the 1978 * case where the supplier is added before the consumer's parent device 1979 * (@dev). 1980 */ 1981 while ((child = fwnode_get_next_available_child_node(fwnode, child))) 1982 __fw_devlink_link_to_suppliers(dev, child); 1983 } 1984 1985 static void fw_devlink_link_device(struct device *dev) 1986 { 1987 struct fwnode_handle *fwnode = dev->fwnode; 1988 1989 if (!fw_devlink_flags) 1990 return; 1991 1992 fw_devlink_parse_fwtree(fwnode); 1993 1994 mutex_lock(&fwnode_link_lock); 1995 __fw_devlink_link_to_consumers(dev); 1996 __fw_devlink_link_to_suppliers(dev, fwnode); 1997 mutex_unlock(&fwnode_link_lock); 1998 } 1999 2000 /* Device links support end. */ 2001 2002 int (*platform_notify)(struct device *dev) = NULL; 2003 int (*platform_notify_remove)(struct device *dev) = NULL; 2004 static struct kobject *dev_kobj; 2005 struct kobject *sysfs_dev_char_kobj; 2006 struct kobject *sysfs_dev_block_kobj; 2007 2008 static DEFINE_MUTEX(device_hotplug_lock); 2009 2010 void lock_device_hotplug(void) 2011 { 2012 mutex_lock(&device_hotplug_lock); 2013 } 2014 2015 void unlock_device_hotplug(void) 2016 { 2017 mutex_unlock(&device_hotplug_lock); 2018 } 2019 2020 int lock_device_hotplug_sysfs(void) 2021 { 2022 if (mutex_trylock(&device_hotplug_lock)) 2023 return 0; 2024 2025 /* Avoid busy looping (5 ms of sleep should do). */ 2026 msleep(5); 2027 return restart_syscall(); 2028 } 2029 2030 #ifdef CONFIG_BLOCK 2031 static inline int device_is_not_partition(struct device *dev) 2032 { 2033 return !(dev->type == &part_type); 2034 } 2035 #else 2036 static inline int device_is_not_partition(struct device *dev) 2037 { 2038 return 1; 2039 } 2040 #endif 2041 2042 static void device_platform_notify(struct device *dev) 2043 { 2044 acpi_device_notify(dev); 2045 2046 software_node_notify(dev); 2047 2048 if (platform_notify) 2049 platform_notify(dev); 2050 } 2051 2052 static void device_platform_notify_remove(struct device *dev) 2053 { 2054 acpi_device_notify_remove(dev); 2055 2056 software_node_notify_remove(dev); 2057 2058 if (platform_notify_remove) 2059 platform_notify_remove(dev); 2060 } 2061 2062 /** 2063 * dev_driver_string - Return a device's driver name, if at all possible 2064 * @dev: struct device to get the name of 2065 * 2066 * Will return the device's driver's name if it is bound to a device. If 2067 * the device is not bound to a driver, it will return the name of the bus 2068 * it is attached to. If it is not attached to a bus either, an empty 2069 * string will be returned. 2070 */ 2071 const char *dev_driver_string(const struct device *dev) 2072 { 2073 struct device_driver *drv; 2074 2075 /* dev->driver can change to NULL underneath us because of unbinding, 2076 * so be careful about accessing it. dev->bus and dev->class should 2077 * never change once they are set, so they don't need special care. 2078 */ 2079 drv = READ_ONCE(dev->driver); 2080 return drv ? drv->name : dev_bus_name(dev); 2081 } 2082 EXPORT_SYMBOL(dev_driver_string); 2083 2084 #define to_dev_attr(_attr) container_of(_attr, struct device_attribute, attr) 2085 2086 static ssize_t dev_attr_show(struct kobject *kobj, struct attribute *attr, 2087 char *buf) 2088 { 2089 struct device_attribute *dev_attr = to_dev_attr(attr); 2090 struct device *dev = kobj_to_dev(kobj); 2091 ssize_t ret = -EIO; 2092 2093 if (dev_attr->show) 2094 ret = dev_attr->show(dev, dev_attr, buf); 2095 if (ret >= (ssize_t)PAGE_SIZE) { 2096 printk("dev_attr_show: %pS returned bad count\n", 2097 dev_attr->show); 2098 } 2099 return ret; 2100 } 2101 2102 static ssize_t dev_attr_store(struct kobject *kobj, struct attribute *attr, 2103 const char *buf, size_t count) 2104 { 2105 struct device_attribute *dev_attr = to_dev_attr(attr); 2106 struct device *dev = kobj_to_dev(kobj); 2107 ssize_t ret = -EIO; 2108 2109 if (dev_attr->store) 2110 ret = dev_attr->store(dev, dev_attr, buf, count); 2111 return ret; 2112 } 2113 2114 static const struct sysfs_ops dev_sysfs_ops = { 2115 .show = dev_attr_show, 2116 .store = dev_attr_store, 2117 }; 2118 2119 #define to_ext_attr(x) container_of(x, struct dev_ext_attribute, attr) 2120 2121 ssize_t device_store_ulong(struct device *dev, 2122 struct device_attribute *attr, 2123 const char *buf, size_t size) 2124 { 2125 struct dev_ext_attribute *ea = to_ext_attr(attr); 2126 int ret; 2127 unsigned long new; 2128 2129 ret = kstrtoul(buf, 0, &new); 2130 if (ret) 2131 return ret; 2132 *(unsigned long *)(ea->var) = new; 2133 /* Always return full write size even if we didn't consume all */ 2134 return size; 2135 } 2136 EXPORT_SYMBOL_GPL(device_store_ulong); 2137 2138 ssize_t device_show_ulong(struct device *dev, 2139 struct device_attribute *attr, 2140 char *buf) 2141 { 2142 struct dev_ext_attribute *ea = to_ext_attr(attr); 2143 return sysfs_emit(buf, "%lx\n", *(unsigned long *)(ea->var)); 2144 } 2145 EXPORT_SYMBOL_GPL(device_show_ulong); 2146 2147 ssize_t device_store_int(struct device *dev, 2148 struct device_attribute *attr, 2149 const char *buf, size_t size) 2150 { 2151 struct dev_ext_attribute *ea = to_ext_attr(attr); 2152 int ret; 2153 long new; 2154 2155 ret = kstrtol(buf, 0, &new); 2156 if (ret) 2157 return ret; 2158 2159 if (new > INT_MAX || new < INT_MIN) 2160 return -EINVAL; 2161 *(int *)(ea->var) = new; 2162 /* Always return full write size even if we didn't consume all */ 2163 return size; 2164 } 2165 EXPORT_SYMBOL_GPL(device_store_int); 2166 2167 ssize_t device_show_int(struct device *dev, 2168 struct device_attribute *attr, 2169 char *buf) 2170 { 2171 struct dev_ext_attribute *ea = to_ext_attr(attr); 2172 2173 return sysfs_emit(buf, "%d\n", *(int *)(ea->var)); 2174 } 2175 EXPORT_SYMBOL_GPL(device_show_int); 2176 2177 ssize_t device_store_bool(struct device *dev, struct device_attribute *attr, 2178 const char *buf, size_t size) 2179 { 2180 struct dev_ext_attribute *ea = to_ext_attr(attr); 2181 2182 if (strtobool(buf, ea->var) < 0) 2183 return -EINVAL; 2184 2185 return size; 2186 } 2187 EXPORT_SYMBOL_GPL(device_store_bool); 2188 2189 ssize_t device_show_bool(struct device *dev, struct device_attribute *attr, 2190 char *buf) 2191 { 2192 struct dev_ext_attribute *ea = to_ext_attr(attr); 2193 2194 return sysfs_emit(buf, "%d\n", *(bool *)(ea->var)); 2195 } 2196 EXPORT_SYMBOL_GPL(device_show_bool); 2197 2198 /** 2199 * device_release - free device structure. 2200 * @kobj: device's kobject. 2201 * 2202 * This is called once the reference count for the object 2203 * reaches 0. We forward the call to the device's release 2204 * method, which should handle actually freeing the structure. 2205 */ 2206 static void device_release(struct kobject *kobj) 2207 { 2208 struct device *dev = kobj_to_dev(kobj); 2209 struct device_private *p = dev->p; 2210 2211 /* 2212 * Some platform devices are driven without driver attached 2213 * and managed resources may have been acquired. Make sure 2214 * all resources are released. 2215 * 2216 * Drivers still can add resources into device after device 2217 * is deleted but alive, so release devres here to avoid 2218 * possible memory leak. 2219 */ 2220 devres_release_all(dev); 2221 2222 kfree(dev->dma_range_map); 2223 2224 if (dev->release) 2225 dev->release(dev); 2226 else if (dev->type && dev->type->release) 2227 dev->type->release(dev); 2228 else if (dev->class && dev->class->dev_release) 2229 dev->class->dev_release(dev); 2230 else 2231 WARN(1, KERN_ERR "Device '%s' does not have a release() function, it is broken and must be fixed. See Documentation/core-api/kobject.rst.\n", 2232 dev_name(dev)); 2233 kfree(p); 2234 } 2235 2236 static const void *device_namespace(struct kobject *kobj) 2237 { 2238 struct device *dev = kobj_to_dev(kobj); 2239 const void *ns = NULL; 2240 2241 if (dev->class && dev->class->ns_type) 2242 ns = dev->class->namespace(dev); 2243 2244 return ns; 2245 } 2246 2247 static void device_get_ownership(struct kobject *kobj, kuid_t *uid, kgid_t *gid) 2248 { 2249 struct device *dev = kobj_to_dev(kobj); 2250 2251 if (dev->class && dev->class->get_ownership) 2252 dev->class->get_ownership(dev, uid, gid); 2253 } 2254 2255 static struct kobj_type device_ktype = { 2256 .release = device_release, 2257 .sysfs_ops = &dev_sysfs_ops, 2258 .namespace = device_namespace, 2259 .get_ownership = device_get_ownership, 2260 }; 2261 2262 2263 static int dev_uevent_filter(struct kobject *kobj) 2264 { 2265 const struct kobj_type *ktype = get_ktype(kobj); 2266 2267 if (ktype == &device_ktype) { 2268 struct device *dev = kobj_to_dev(kobj); 2269 if (dev->bus) 2270 return 1; 2271 if (dev->class) 2272 return 1; 2273 } 2274 return 0; 2275 } 2276 2277 static const char *dev_uevent_name(struct kobject *kobj) 2278 { 2279 struct device *dev = kobj_to_dev(kobj); 2280 2281 if (dev->bus) 2282 return dev->bus->name; 2283 if (dev->class) 2284 return dev->class->name; 2285 return NULL; 2286 } 2287 2288 static int dev_uevent(struct kobject *kobj, struct kobj_uevent_env *env) 2289 { 2290 struct device *dev = kobj_to_dev(kobj); 2291 int retval = 0; 2292 2293 /* add device node properties if present */ 2294 if (MAJOR(dev->devt)) { 2295 const char *tmp; 2296 const char *name; 2297 umode_t mode = 0; 2298 kuid_t uid = GLOBAL_ROOT_UID; 2299 kgid_t gid = GLOBAL_ROOT_GID; 2300 2301 add_uevent_var(env, "MAJOR=%u", MAJOR(dev->devt)); 2302 add_uevent_var(env, "MINOR=%u", MINOR(dev->devt)); 2303 name = device_get_devnode(dev, &mode, &uid, &gid, &tmp); 2304 if (name) { 2305 add_uevent_var(env, "DEVNAME=%s", name); 2306 if (mode) 2307 add_uevent_var(env, "DEVMODE=%#o", mode & 0777); 2308 if (!uid_eq(uid, GLOBAL_ROOT_UID)) 2309 add_uevent_var(env, "DEVUID=%u", from_kuid(&init_user_ns, uid)); 2310 if (!gid_eq(gid, GLOBAL_ROOT_GID)) 2311 add_uevent_var(env, "DEVGID=%u", from_kgid(&init_user_ns, gid)); 2312 kfree(tmp); 2313 } 2314 } 2315 2316 if (dev->type && dev->type->name) 2317 add_uevent_var(env, "DEVTYPE=%s", dev->type->name); 2318 2319 if (dev->driver) 2320 add_uevent_var(env, "DRIVER=%s", dev->driver->name); 2321 2322 /* Add common DT information about the device */ 2323 of_device_uevent(dev, env); 2324 2325 /* have the bus specific function add its stuff */ 2326 if (dev->bus && dev->bus->uevent) { 2327 retval = dev->bus->uevent(dev, env); 2328 if (retval) 2329 pr_debug("device: '%s': %s: bus uevent() returned %d\n", 2330 dev_name(dev), __func__, retval); 2331 } 2332 2333 /* have the class specific function add its stuff */ 2334 if (dev->class && dev->class->dev_uevent) { 2335 retval = dev->class->dev_uevent(dev, env); 2336 if (retval) 2337 pr_debug("device: '%s': %s: class uevent() " 2338 "returned %d\n", dev_name(dev), 2339 __func__, retval); 2340 } 2341 2342 /* have the device type specific function add its stuff */ 2343 if (dev->type && dev->type->uevent) { 2344 retval = dev->type->uevent(dev, env); 2345 if (retval) 2346 pr_debug("device: '%s': %s: dev_type uevent() " 2347 "returned %d\n", dev_name(dev), 2348 __func__, retval); 2349 } 2350 2351 return retval; 2352 } 2353 2354 static const struct kset_uevent_ops device_uevent_ops = { 2355 .filter = dev_uevent_filter, 2356 .name = dev_uevent_name, 2357 .uevent = dev_uevent, 2358 }; 2359 2360 static ssize_t uevent_show(struct device *dev, struct device_attribute *attr, 2361 char *buf) 2362 { 2363 struct kobject *top_kobj; 2364 struct kset *kset; 2365 struct kobj_uevent_env *env = NULL; 2366 int i; 2367 int len = 0; 2368 int retval; 2369 2370 /* search the kset, the device belongs to */ 2371 top_kobj = &dev->kobj; 2372 while (!top_kobj->kset && top_kobj->parent) 2373 top_kobj = top_kobj->parent; 2374 if (!top_kobj->kset) 2375 goto out; 2376 2377 kset = top_kobj->kset; 2378 if (!kset->uevent_ops || !kset->uevent_ops->uevent) 2379 goto out; 2380 2381 /* respect filter */ 2382 if (kset->uevent_ops && kset->uevent_ops->filter) 2383 if (!kset->uevent_ops->filter(&dev->kobj)) 2384 goto out; 2385 2386 env = kzalloc(sizeof(struct kobj_uevent_env), GFP_KERNEL); 2387 if (!env) 2388 return -ENOMEM; 2389 2390 /* let the kset specific function add its keys */ 2391 retval = kset->uevent_ops->uevent(&dev->kobj, env); 2392 if (retval) 2393 goto out; 2394 2395 /* copy keys to file */ 2396 for (i = 0; i < env->envp_idx; i++) 2397 len += sysfs_emit_at(buf, len, "%s\n", env->envp[i]); 2398 out: 2399 kfree(env); 2400 return len; 2401 } 2402 2403 static ssize_t uevent_store(struct device *dev, struct device_attribute *attr, 2404 const char *buf, size_t count) 2405 { 2406 int rc; 2407 2408 rc = kobject_synth_uevent(&dev->kobj, buf, count); 2409 2410 if (rc) { 2411 dev_err(dev, "uevent: failed to send synthetic uevent\n"); 2412 return rc; 2413 } 2414 2415 return count; 2416 } 2417 static DEVICE_ATTR_RW(uevent); 2418 2419 static ssize_t online_show(struct device *dev, struct device_attribute *attr, 2420 char *buf) 2421 { 2422 bool val; 2423 2424 device_lock(dev); 2425 val = !dev->offline; 2426 device_unlock(dev); 2427 return sysfs_emit(buf, "%u\n", val); 2428 } 2429 2430 static ssize_t online_store(struct device *dev, struct device_attribute *attr, 2431 const char *buf, size_t count) 2432 { 2433 bool val; 2434 int ret; 2435 2436 ret = strtobool(buf, &val); 2437 if (ret < 0) 2438 return ret; 2439 2440 ret = lock_device_hotplug_sysfs(); 2441 if (ret) 2442 return ret; 2443 2444 ret = val ? device_online(dev) : device_offline(dev); 2445 unlock_device_hotplug(); 2446 return ret < 0 ? ret : count; 2447 } 2448 static DEVICE_ATTR_RW(online); 2449 2450 static ssize_t removable_show(struct device *dev, struct device_attribute *attr, 2451 char *buf) 2452 { 2453 const char *loc; 2454 2455 switch (dev->removable) { 2456 case DEVICE_REMOVABLE: 2457 loc = "removable"; 2458 break; 2459 case DEVICE_FIXED: 2460 loc = "fixed"; 2461 break; 2462 default: 2463 loc = "unknown"; 2464 } 2465 return sysfs_emit(buf, "%s\n", loc); 2466 } 2467 static DEVICE_ATTR_RO(removable); 2468 2469 int device_add_groups(struct device *dev, const struct attribute_group **groups) 2470 { 2471 return sysfs_create_groups(&dev->kobj, groups); 2472 } 2473 EXPORT_SYMBOL_GPL(device_add_groups); 2474 2475 void device_remove_groups(struct device *dev, 2476 const struct attribute_group **groups) 2477 { 2478 sysfs_remove_groups(&dev->kobj, groups); 2479 } 2480 EXPORT_SYMBOL_GPL(device_remove_groups); 2481 2482 union device_attr_group_devres { 2483 const struct attribute_group *group; 2484 const struct attribute_group **groups; 2485 }; 2486 2487 static int devm_attr_group_match(struct device *dev, void *res, void *data) 2488 { 2489 return ((union device_attr_group_devres *)res)->group == data; 2490 } 2491 2492 static void devm_attr_group_remove(struct device *dev, void *res) 2493 { 2494 union device_attr_group_devres *devres = res; 2495 const struct attribute_group *group = devres->group; 2496 2497 dev_dbg(dev, "%s: removing group %p\n", __func__, group); 2498 sysfs_remove_group(&dev->kobj, group); 2499 } 2500 2501 static void devm_attr_groups_remove(struct device *dev, void *res) 2502 { 2503 union device_attr_group_devres *devres = res; 2504 const struct attribute_group **groups = devres->groups; 2505 2506 dev_dbg(dev, "%s: removing groups %p\n", __func__, groups); 2507 sysfs_remove_groups(&dev->kobj, groups); 2508 } 2509 2510 /** 2511 * devm_device_add_group - given a device, create a managed attribute group 2512 * @dev: The device to create the group for 2513 * @grp: The attribute group to create 2514 * 2515 * This function creates a group for the first time. It will explicitly 2516 * warn and error if any of the attribute files being created already exist. 2517 * 2518 * Returns 0 on success or error code on failure. 2519 */ 2520 int devm_device_add_group(struct device *dev, const struct attribute_group *grp) 2521 { 2522 union device_attr_group_devres *devres; 2523 int error; 2524 2525 devres = devres_alloc(devm_attr_group_remove, 2526 sizeof(*devres), GFP_KERNEL); 2527 if (!devres) 2528 return -ENOMEM; 2529 2530 error = sysfs_create_group(&dev->kobj, grp); 2531 if (error) { 2532 devres_free(devres); 2533 return error; 2534 } 2535 2536 devres->group = grp; 2537 devres_add(dev, devres); 2538 return 0; 2539 } 2540 EXPORT_SYMBOL_GPL(devm_device_add_group); 2541 2542 /** 2543 * devm_device_remove_group: remove a managed group from a device 2544 * @dev: device to remove the group from 2545 * @grp: group to remove 2546 * 2547 * This function removes a group of attributes from a device. The attributes 2548 * previously have to have been created for this group, otherwise it will fail. 2549 */ 2550 void devm_device_remove_group(struct device *dev, 2551 const struct attribute_group *grp) 2552 { 2553 WARN_ON(devres_release(dev, devm_attr_group_remove, 2554 devm_attr_group_match, 2555 /* cast away const */ (void *)grp)); 2556 } 2557 EXPORT_SYMBOL_GPL(devm_device_remove_group); 2558 2559 /** 2560 * devm_device_add_groups - create a bunch of managed attribute groups 2561 * @dev: The device to create the group for 2562 * @groups: The attribute groups to create, NULL terminated 2563 * 2564 * This function creates a bunch of managed attribute groups. If an error 2565 * occurs when creating a group, all previously created groups will be 2566 * removed, unwinding everything back to the original state when this 2567 * function was called. It will explicitly warn and error if any of the 2568 * attribute files being created already exist. 2569 * 2570 * Returns 0 on success or error code from sysfs_create_group on failure. 2571 */ 2572 int devm_device_add_groups(struct device *dev, 2573 const struct attribute_group **groups) 2574 { 2575 union device_attr_group_devres *devres; 2576 int error; 2577 2578 devres = devres_alloc(devm_attr_groups_remove, 2579 sizeof(*devres), GFP_KERNEL); 2580 if (!devres) 2581 return -ENOMEM; 2582 2583 error = sysfs_create_groups(&dev->kobj, groups); 2584 if (error) { 2585 devres_free(devres); 2586 return error; 2587 } 2588 2589 devres->groups = groups; 2590 devres_add(dev, devres); 2591 return 0; 2592 } 2593 EXPORT_SYMBOL_GPL(devm_device_add_groups); 2594 2595 /** 2596 * devm_device_remove_groups - remove a list of managed groups 2597 * 2598 * @dev: The device for the groups to be removed from 2599 * @groups: NULL terminated list of groups to be removed 2600 * 2601 * If groups is not NULL, remove the specified groups from the device. 2602 */ 2603 void devm_device_remove_groups(struct device *dev, 2604 const struct attribute_group **groups) 2605 { 2606 WARN_ON(devres_release(dev, devm_attr_groups_remove, 2607 devm_attr_group_match, 2608 /* cast away const */ (void *)groups)); 2609 } 2610 EXPORT_SYMBOL_GPL(devm_device_remove_groups); 2611 2612 static int device_add_attrs(struct device *dev) 2613 { 2614 struct class *class = dev->class; 2615 const struct device_type *type = dev->type; 2616 int error; 2617 2618 if (class) { 2619 error = device_add_groups(dev, class->dev_groups); 2620 if (error) 2621 return error; 2622 } 2623 2624 if (type) { 2625 error = device_add_groups(dev, type->groups); 2626 if (error) 2627 goto err_remove_class_groups; 2628 } 2629 2630 error = device_add_groups(dev, dev->groups); 2631 if (error) 2632 goto err_remove_type_groups; 2633 2634 if (device_supports_offline(dev) && !dev->offline_disabled) { 2635 error = device_create_file(dev, &dev_attr_online); 2636 if (error) 2637 goto err_remove_dev_groups; 2638 } 2639 2640 if (fw_devlink_flags && !fw_devlink_is_permissive() && dev->fwnode) { 2641 error = device_create_file(dev, &dev_attr_waiting_for_supplier); 2642 if (error) 2643 goto err_remove_dev_online; 2644 } 2645 2646 if (dev_removable_is_valid(dev)) { 2647 error = device_create_file(dev, &dev_attr_removable); 2648 if (error) 2649 goto err_remove_dev_waiting_for_supplier; 2650 } 2651 2652 return 0; 2653 2654 err_remove_dev_waiting_for_supplier: 2655 device_remove_file(dev, &dev_attr_waiting_for_supplier); 2656 err_remove_dev_online: 2657 device_remove_file(dev, &dev_attr_online); 2658 err_remove_dev_groups: 2659 device_remove_groups(dev, dev->groups); 2660 err_remove_type_groups: 2661 if (type) 2662 device_remove_groups(dev, type->groups); 2663 err_remove_class_groups: 2664 if (class) 2665 device_remove_groups(dev, class->dev_groups); 2666 2667 return error; 2668 } 2669 2670 static void device_remove_attrs(struct device *dev) 2671 { 2672 struct class *class = dev->class; 2673 const struct device_type *type = dev->type; 2674 2675 device_remove_file(dev, &dev_attr_removable); 2676 device_remove_file(dev, &dev_attr_waiting_for_supplier); 2677 device_remove_file(dev, &dev_attr_online); 2678 device_remove_groups(dev, dev->groups); 2679 2680 if (type) 2681 device_remove_groups(dev, type->groups); 2682 2683 if (class) 2684 device_remove_groups(dev, class->dev_groups); 2685 } 2686 2687 static ssize_t dev_show(struct device *dev, struct device_attribute *attr, 2688 char *buf) 2689 { 2690 return print_dev_t(buf, dev->devt); 2691 } 2692 static DEVICE_ATTR_RO(dev); 2693 2694 /* /sys/devices/ */ 2695 struct kset *devices_kset; 2696 2697 /** 2698 * devices_kset_move_before - Move device in the devices_kset's list. 2699 * @deva: Device to move. 2700 * @devb: Device @deva should come before. 2701 */ 2702 static void devices_kset_move_before(struct device *deva, struct device *devb) 2703 { 2704 if (!devices_kset) 2705 return; 2706 pr_debug("devices_kset: Moving %s before %s\n", 2707 dev_name(deva), dev_name(devb)); 2708 spin_lock(&devices_kset->list_lock); 2709 list_move_tail(&deva->kobj.entry, &devb->kobj.entry); 2710 spin_unlock(&devices_kset->list_lock); 2711 } 2712 2713 /** 2714 * devices_kset_move_after - Move device in the devices_kset's list. 2715 * @deva: Device to move 2716 * @devb: Device @deva should come after. 2717 */ 2718 static void devices_kset_move_after(struct device *deva, struct device *devb) 2719 { 2720 if (!devices_kset) 2721 return; 2722 pr_debug("devices_kset: Moving %s after %s\n", 2723 dev_name(deva), dev_name(devb)); 2724 spin_lock(&devices_kset->list_lock); 2725 list_move(&deva->kobj.entry, &devb->kobj.entry); 2726 spin_unlock(&devices_kset->list_lock); 2727 } 2728 2729 /** 2730 * devices_kset_move_last - move the device to the end of devices_kset's list. 2731 * @dev: device to move 2732 */ 2733 void devices_kset_move_last(struct device *dev) 2734 { 2735 if (!devices_kset) 2736 return; 2737 pr_debug("devices_kset: Moving %s to end of list\n", dev_name(dev)); 2738 spin_lock(&devices_kset->list_lock); 2739 list_move_tail(&dev->kobj.entry, &devices_kset->list); 2740 spin_unlock(&devices_kset->list_lock); 2741 } 2742 2743 /** 2744 * device_create_file - create sysfs attribute file for device. 2745 * @dev: device. 2746 * @attr: device attribute descriptor. 2747 */ 2748 int device_create_file(struct device *dev, 2749 const struct device_attribute *attr) 2750 { 2751 int error = 0; 2752 2753 if (dev) { 2754 WARN(((attr->attr.mode & S_IWUGO) && !attr->store), 2755 "Attribute %s: write permission without 'store'\n", 2756 attr->attr.name); 2757 WARN(((attr->attr.mode & S_IRUGO) && !attr->show), 2758 "Attribute %s: read permission without 'show'\n", 2759 attr->attr.name); 2760 error = sysfs_create_file(&dev->kobj, &attr->attr); 2761 } 2762 2763 return error; 2764 } 2765 EXPORT_SYMBOL_GPL(device_create_file); 2766 2767 /** 2768 * device_remove_file - remove sysfs attribute file. 2769 * @dev: device. 2770 * @attr: device attribute descriptor. 2771 */ 2772 void device_remove_file(struct device *dev, 2773 const struct device_attribute *attr) 2774 { 2775 if (dev) 2776 sysfs_remove_file(&dev->kobj, &attr->attr); 2777 } 2778 EXPORT_SYMBOL_GPL(device_remove_file); 2779 2780 /** 2781 * device_remove_file_self - remove sysfs attribute file from its own method. 2782 * @dev: device. 2783 * @attr: device attribute descriptor. 2784 * 2785 * See kernfs_remove_self() for details. 2786 */ 2787 bool device_remove_file_self(struct device *dev, 2788 const struct device_attribute *attr) 2789 { 2790 if (dev) 2791 return sysfs_remove_file_self(&dev->kobj, &attr->attr); 2792 else 2793 return false; 2794 } 2795 EXPORT_SYMBOL_GPL(device_remove_file_self); 2796 2797 /** 2798 * device_create_bin_file - create sysfs binary attribute file for device. 2799 * @dev: device. 2800 * @attr: device binary attribute descriptor. 2801 */ 2802 int device_create_bin_file(struct device *dev, 2803 const struct bin_attribute *attr) 2804 { 2805 int error = -EINVAL; 2806 if (dev) 2807 error = sysfs_create_bin_file(&dev->kobj, attr); 2808 return error; 2809 } 2810 EXPORT_SYMBOL_GPL(device_create_bin_file); 2811 2812 /** 2813 * device_remove_bin_file - remove sysfs binary attribute file 2814 * @dev: device. 2815 * @attr: device binary attribute descriptor. 2816 */ 2817 void device_remove_bin_file(struct device *dev, 2818 const struct bin_attribute *attr) 2819 { 2820 if (dev) 2821 sysfs_remove_bin_file(&dev->kobj, attr); 2822 } 2823 EXPORT_SYMBOL_GPL(device_remove_bin_file); 2824 2825 static void klist_children_get(struct klist_node *n) 2826 { 2827 struct device_private *p = to_device_private_parent(n); 2828 struct device *dev = p->device; 2829 2830 get_device(dev); 2831 } 2832 2833 static void klist_children_put(struct klist_node *n) 2834 { 2835 struct device_private *p = to_device_private_parent(n); 2836 struct device *dev = p->device; 2837 2838 put_device(dev); 2839 } 2840 2841 /** 2842 * device_initialize - init device structure. 2843 * @dev: device. 2844 * 2845 * This prepares the device for use by other layers by initializing 2846 * its fields. 2847 * It is the first half of device_register(), if called by 2848 * that function, though it can also be called separately, so one 2849 * may use @dev's fields. In particular, get_device()/put_device() 2850 * may be used for reference counting of @dev after calling this 2851 * function. 2852 * 2853 * All fields in @dev must be initialized by the caller to 0, except 2854 * for those explicitly set to some other value. The simplest 2855 * approach is to use kzalloc() to allocate the structure containing 2856 * @dev. 2857 * 2858 * NOTE: Use put_device() to give up your reference instead of freeing 2859 * @dev directly once you have called this function. 2860 */ 2861 void device_initialize(struct device *dev) 2862 { 2863 dev->kobj.kset = devices_kset; 2864 kobject_init(&dev->kobj, &device_ktype); 2865 INIT_LIST_HEAD(&dev->dma_pools); 2866 mutex_init(&dev->mutex); 2867 lockdep_set_novalidate_class(&dev->mutex); 2868 spin_lock_init(&dev->devres_lock); 2869 INIT_LIST_HEAD(&dev->devres_head); 2870 device_pm_init(dev); 2871 set_dev_node(dev, NUMA_NO_NODE); 2872 INIT_LIST_HEAD(&dev->links.consumers); 2873 INIT_LIST_HEAD(&dev->links.suppliers); 2874 INIT_LIST_HEAD(&dev->links.defer_sync); 2875 dev->links.status = DL_DEV_NO_DRIVER; 2876 #if defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_DEVICE) || \ 2877 defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU) || \ 2878 defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU_ALL) 2879 dev->dma_coherent = dma_default_coherent; 2880 #endif 2881 #ifdef CONFIG_SWIOTLB 2882 dev->dma_io_tlb_mem = &io_tlb_default_mem; 2883 #endif 2884 } 2885 EXPORT_SYMBOL_GPL(device_initialize); 2886 2887 struct kobject *virtual_device_parent(struct device *dev) 2888 { 2889 static struct kobject *virtual_dir = NULL; 2890 2891 if (!virtual_dir) 2892 virtual_dir = kobject_create_and_add("virtual", 2893 &devices_kset->kobj); 2894 2895 return virtual_dir; 2896 } 2897 2898 struct class_dir { 2899 struct kobject kobj; 2900 struct class *class; 2901 }; 2902 2903 #define to_class_dir(obj) container_of(obj, struct class_dir, kobj) 2904 2905 static void class_dir_release(struct kobject *kobj) 2906 { 2907 struct class_dir *dir = to_class_dir(kobj); 2908 kfree(dir); 2909 } 2910 2911 static const 2912 struct kobj_ns_type_operations *class_dir_child_ns_type(struct kobject *kobj) 2913 { 2914 struct class_dir *dir = to_class_dir(kobj); 2915 return dir->class->ns_type; 2916 } 2917 2918 static struct kobj_type class_dir_ktype = { 2919 .release = class_dir_release, 2920 .sysfs_ops = &kobj_sysfs_ops, 2921 .child_ns_type = class_dir_child_ns_type 2922 }; 2923 2924 static struct kobject * 2925 class_dir_create_and_add(struct class *class, struct kobject *parent_kobj) 2926 { 2927 struct class_dir *dir; 2928 int retval; 2929 2930 dir = kzalloc(sizeof(*dir), GFP_KERNEL); 2931 if (!dir) 2932 return ERR_PTR(-ENOMEM); 2933 2934 dir->class = class; 2935 kobject_init(&dir->kobj, &class_dir_ktype); 2936 2937 dir->kobj.kset = &class->p->glue_dirs; 2938 2939 retval = kobject_add(&dir->kobj, parent_kobj, "%s", class->name); 2940 if (retval < 0) { 2941 kobject_put(&dir->kobj); 2942 return ERR_PTR(retval); 2943 } 2944 return &dir->kobj; 2945 } 2946 2947 static DEFINE_MUTEX(gdp_mutex); 2948 2949 static struct kobject *get_device_parent(struct device *dev, 2950 struct device *parent) 2951 { 2952 if (dev->class) { 2953 struct kobject *kobj = NULL; 2954 struct kobject *parent_kobj; 2955 struct kobject *k; 2956 2957 #ifdef CONFIG_BLOCK 2958 /* block disks show up in /sys/block */ 2959 if (sysfs_deprecated && dev->class == &block_class) { 2960 if (parent && parent->class == &block_class) 2961 return &parent->kobj; 2962 return &block_class.p->subsys.kobj; 2963 } 2964 #endif 2965 2966 /* 2967 * If we have no parent, we live in "virtual". 2968 * Class-devices with a non class-device as parent, live 2969 * in a "glue" directory to prevent namespace collisions. 2970 */ 2971 if (parent == NULL) 2972 parent_kobj = virtual_device_parent(dev); 2973 else if (parent->class && !dev->class->ns_type) 2974 return &parent->kobj; 2975 else 2976 parent_kobj = &parent->kobj; 2977 2978 mutex_lock(&gdp_mutex); 2979 2980 /* find our class-directory at the parent and reference it */ 2981 spin_lock(&dev->class->p->glue_dirs.list_lock); 2982 list_for_each_entry(k, &dev->class->p->glue_dirs.list, entry) 2983 if (k->parent == parent_kobj) { 2984 kobj = kobject_get(k); 2985 break; 2986 } 2987 spin_unlock(&dev->class->p->glue_dirs.list_lock); 2988 if (kobj) { 2989 mutex_unlock(&gdp_mutex); 2990 return kobj; 2991 } 2992 2993 /* or create a new class-directory at the parent device */ 2994 k = class_dir_create_and_add(dev->class, parent_kobj); 2995 /* do not emit an uevent for this simple "glue" directory */ 2996 mutex_unlock(&gdp_mutex); 2997 return k; 2998 } 2999 3000 /* subsystems can specify a default root directory for their devices */ 3001 if (!parent && dev->bus && dev->bus->dev_root) 3002 return &dev->bus->dev_root->kobj; 3003 3004 if (parent) 3005 return &parent->kobj; 3006 return NULL; 3007 } 3008 3009 static inline bool live_in_glue_dir(struct kobject *kobj, 3010 struct device *dev) 3011 { 3012 if (!kobj || !dev->class || 3013 kobj->kset != &dev->class->p->glue_dirs) 3014 return false; 3015 return true; 3016 } 3017 3018 static inline struct kobject *get_glue_dir(struct device *dev) 3019 { 3020 return dev->kobj.parent; 3021 } 3022 3023 /** 3024 * kobject_has_children - Returns whether a kobject has children. 3025 * @kobj: the object to test 3026 * 3027 * This will return whether a kobject has other kobjects as children. 3028 * 3029 * It does NOT account for the presence of attribute files, only sub 3030 * directories. It also assumes there is no concurrent addition or 3031 * removal of such children, and thus relies on external locking. 3032 */ 3033 static inline bool kobject_has_children(struct kobject *kobj) 3034 { 3035 WARN_ON_ONCE(kref_read(&kobj->kref) == 0); 3036 3037 return kobj->sd && kobj->sd->dir.subdirs; 3038 } 3039 3040 /* 3041 * make sure cleaning up dir as the last step, we need to make 3042 * sure .release handler of kobject is run with holding the 3043 * global lock 3044 */ 3045 static void cleanup_glue_dir(struct device *dev, struct kobject *glue_dir) 3046 { 3047 unsigned int ref; 3048 3049 /* see if we live in a "glue" directory */ 3050 if (!live_in_glue_dir(glue_dir, dev)) 3051 return; 3052 3053 mutex_lock(&gdp_mutex); 3054 /** 3055 * There is a race condition between removing glue directory 3056 * and adding a new device under the glue directory. 3057 * 3058 * CPU1: CPU2: 3059 * 3060 * device_add() 3061 * get_device_parent() 3062 * class_dir_create_and_add() 3063 * kobject_add_internal() 3064 * create_dir() // create glue_dir 3065 * 3066 * device_add() 3067 * get_device_parent() 3068 * kobject_get() // get glue_dir 3069 * 3070 * device_del() 3071 * cleanup_glue_dir() 3072 * kobject_del(glue_dir) 3073 * 3074 * kobject_add() 3075 * kobject_add_internal() 3076 * create_dir() // in glue_dir 3077 * sysfs_create_dir_ns() 3078 * kernfs_create_dir_ns(sd) 3079 * 3080 * sysfs_remove_dir() // glue_dir->sd=NULL 3081 * sysfs_put() // free glue_dir->sd 3082 * 3083 * // sd is freed 3084 * kernfs_new_node(sd) 3085 * kernfs_get(glue_dir) 3086 * kernfs_add_one() 3087 * kernfs_put() 3088 * 3089 * Before CPU1 remove last child device under glue dir, if CPU2 add 3090 * a new device under glue dir, the glue_dir kobject reference count 3091 * will be increase to 2 in kobject_get(k). And CPU2 has been called 3092 * kernfs_create_dir_ns(). Meanwhile, CPU1 call sysfs_remove_dir() 3093 * and sysfs_put(). This result in glue_dir->sd is freed. 3094 * 3095 * Then the CPU2 will see a stale "empty" but still potentially used 3096 * glue dir around in kernfs_new_node(). 3097 * 3098 * In order to avoid this happening, we also should make sure that 3099 * kernfs_node for glue_dir is released in CPU1 only when refcount 3100 * for glue_dir kobj is 1. 3101 */ 3102 ref = kref_read(&glue_dir->kref); 3103 if (!kobject_has_children(glue_dir) && !--ref) 3104 kobject_del(glue_dir); 3105 kobject_put(glue_dir); 3106 mutex_unlock(&gdp_mutex); 3107 } 3108 3109 static int device_add_class_symlinks(struct device *dev) 3110 { 3111 struct device_node *of_node = dev_of_node(dev); 3112 int error; 3113 3114 if (of_node) { 3115 error = sysfs_create_link(&dev->kobj, of_node_kobj(of_node), "of_node"); 3116 if (error) 3117 dev_warn(dev, "Error %d creating of_node link\n",error); 3118 /* An error here doesn't warrant bringing down the device */ 3119 } 3120 3121 if (!dev->class) 3122 return 0; 3123 3124 error = sysfs_create_link(&dev->kobj, 3125 &dev->class->p->subsys.kobj, 3126 "subsystem"); 3127 if (error) 3128 goto out_devnode; 3129 3130 if (dev->parent && device_is_not_partition(dev)) { 3131 error = sysfs_create_link(&dev->kobj, &dev->parent->kobj, 3132 "device"); 3133 if (error) 3134 goto out_subsys; 3135 } 3136 3137 #ifdef CONFIG_BLOCK 3138 /* /sys/block has directories and does not need symlinks */ 3139 if (sysfs_deprecated && dev->class == &block_class) 3140 return 0; 3141 #endif 3142 3143 /* link in the class directory pointing to the device */ 3144 error = sysfs_create_link(&dev->class->p->subsys.kobj, 3145 &dev->kobj, dev_name(dev)); 3146 if (error) 3147 goto out_device; 3148 3149 return 0; 3150 3151 out_device: 3152 sysfs_remove_link(&dev->kobj, "device"); 3153 3154 out_subsys: 3155 sysfs_remove_link(&dev->kobj, "subsystem"); 3156 out_devnode: 3157 sysfs_remove_link(&dev->kobj, "of_node"); 3158 return error; 3159 } 3160 3161 static void device_remove_class_symlinks(struct device *dev) 3162 { 3163 if (dev_of_node(dev)) 3164 sysfs_remove_link(&dev->kobj, "of_node"); 3165 3166 if (!dev->class) 3167 return; 3168 3169 if (dev->parent && device_is_not_partition(dev)) 3170 sysfs_remove_link(&dev->kobj, "device"); 3171 sysfs_remove_link(&dev->kobj, "subsystem"); 3172 #ifdef CONFIG_BLOCK 3173 if (sysfs_deprecated && dev->class == &block_class) 3174 return; 3175 #endif 3176 sysfs_delete_link(&dev->class->p->subsys.kobj, &dev->kobj, dev_name(dev)); 3177 } 3178 3179 /** 3180 * dev_set_name - set a device name 3181 * @dev: device 3182 * @fmt: format string for the device's name 3183 */ 3184 int dev_set_name(struct device *dev, const char *fmt, ...) 3185 { 3186 va_list vargs; 3187 int err; 3188 3189 va_start(vargs, fmt); 3190 err = kobject_set_name_vargs(&dev->kobj, fmt, vargs); 3191 va_end(vargs); 3192 return err; 3193 } 3194 EXPORT_SYMBOL_GPL(dev_set_name); 3195 3196 /** 3197 * device_to_dev_kobj - select a /sys/dev/ directory for the device 3198 * @dev: device 3199 * 3200 * By default we select char/ for new entries. Setting class->dev_obj 3201 * to NULL prevents an entry from being created. class->dev_kobj must 3202 * be set (or cleared) before any devices are registered to the class 3203 * otherwise device_create_sys_dev_entry() and 3204 * device_remove_sys_dev_entry() will disagree about the presence of 3205 * the link. 3206 */ 3207 static struct kobject *device_to_dev_kobj(struct device *dev) 3208 { 3209 struct kobject *kobj; 3210 3211 if (dev->class) 3212 kobj = dev->class->dev_kobj; 3213 else 3214 kobj = sysfs_dev_char_kobj; 3215 3216 return kobj; 3217 } 3218 3219 static int device_create_sys_dev_entry(struct device *dev) 3220 { 3221 struct kobject *kobj = device_to_dev_kobj(dev); 3222 int error = 0; 3223 char devt_str[15]; 3224 3225 if (kobj) { 3226 format_dev_t(devt_str, dev->devt); 3227 error = sysfs_create_link(kobj, &dev->kobj, devt_str); 3228 } 3229 3230 return error; 3231 } 3232 3233 static void device_remove_sys_dev_entry(struct device *dev) 3234 { 3235 struct kobject *kobj = device_to_dev_kobj(dev); 3236 char devt_str[15]; 3237 3238 if (kobj) { 3239 format_dev_t(devt_str, dev->devt); 3240 sysfs_remove_link(kobj, devt_str); 3241 } 3242 } 3243 3244 static int device_private_init(struct device *dev) 3245 { 3246 dev->p = kzalloc(sizeof(*dev->p), GFP_KERNEL); 3247 if (!dev->p) 3248 return -ENOMEM; 3249 dev->p->device = dev; 3250 klist_init(&dev->p->klist_children, klist_children_get, 3251 klist_children_put); 3252 INIT_LIST_HEAD(&dev->p->deferred_probe); 3253 return 0; 3254 } 3255 3256 /** 3257 * device_add - add device to device hierarchy. 3258 * @dev: device. 3259 * 3260 * This is part 2 of device_register(), though may be called 3261 * separately _iff_ device_initialize() has been called separately. 3262 * 3263 * This adds @dev to the kobject hierarchy via kobject_add(), adds it 3264 * to the global and sibling lists for the device, then 3265 * adds it to the other relevant subsystems of the driver model. 3266 * 3267 * Do not call this routine or device_register() more than once for 3268 * any device structure. The driver model core is not designed to work 3269 * with devices that get unregistered and then spring back to life. 3270 * (Among other things, it's very hard to guarantee that all references 3271 * to the previous incarnation of @dev have been dropped.) Allocate 3272 * and register a fresh new struct device instead. 3273 * 3274 * NOTE: _Never_ directly free @dev after calling this function, even 3275 * if it returned an error! Always use put_device() to give up your 3276 * reference instead. 3277 * 3278 * Rule of thumb is: if device_add() succeeds, you should call 3279 * device_del() when you want to get rid of it. If device_add() has 3280 * *not* succeeded, use *only* put_device() to drop the reference 3281 * count. 3282 */ 3283 int device_add(struct device *dev) 3284 { 3285 struct device *parent; 3286 struct kobject *kobj; 3287 struct class_interface *class_intf; 3288 int error = -EINVAL; 3289 struct kobject *glue_dir = NULL; 3290 3291 dev = get_device(dev); 3292 if (!dev) 3293 goto done; 3294 3295 if (!dev->p) { 3296 error = device_private_init(dev); 3297 if (error) 3298 goto done; 3299 } 3300 3301 /* 3302 * for statically allocated devices, which should all be converted 3303 * some day, we need to initialize the name. We prevent reading back 3304 * the name, and force the use of dev_name() 3305 */ 3306 if (dev->init_name) { 3307 dev_set_name(dev, "%s", dev->init_name); 3308 dev->init_name = NULL; 3309 } 3310 3311 /* subsystems can specify simple device enumeration */ 3312 if (!dev_name(dev) && dev->bus && dev->bus->dev_name) 3313 dev_set_name(dev, "%s%u", dev->bus->dev_name, dev->id); 3314 3315 if (!dev_name(dev)) { 3316 error = -EINVAL; 3317 goto name_error; 3318 } 3319 3320 pr_debug("device: '%s': %s\n", dev_name(dev), __func__); 3321 3322 parent = get_device(dev->parent); 3323 kobj = get_device_parent(dev, parent); 3324 if (IS_ERR(kobj)) { 3325 error = PTR_ERR(kobj); 3326 goto parent_error; 3327 } 3328 if (kobj) 3329 dev->kobj.parent = kobj; 3330 3331 /* use parent numa_node */ 3332 if (parent && (dev_to_node(dev) == NUMA_NO_NODE)) 3333 set_dev_node(dev, dev_to_node(parent)); 3334 3335 /* first, register with generic layer. */ 3336 /* we require the name to be set before, and pass NULL */ 3337 error = kobject_add(&dev->kobj, dev->kobj.parent, NULL); 3338 if (error) { 3339 glue_dir = get_glue_dir(dev); 3340 goto Error; 3341 } 3342 3343 /* notify platform of device entry */ 3344 device_platform_notify(dev); 3345 3346 error = device_create_file(dev, &dev_attr_uevent); 3347 if (error) 3348 goto attrError; 3349 3350 error = device_add_class_symlinks(dev); 3351 if (error) 3352 goto SymlinkError; 3353 error = device_add_attrs(dev); 3354 if (error) 3355 goto AttrsError; 3356 error = bus_add_device(dev); 3357 if (error) 3358 goto BusError; 3359 error = dpm_sysfs_add(dev); 3360 if (error) 3361 goto DPMError; 3362 device_pm_add(dev); 3363 3364 if (MAJOR(dev->devt)) { 3365 error = device_create_file(dev, &dev_attr_dev); 3366 if (error) 3367 goto DevAttrError; 3368 3369 error = device_create_sys_dev_entry(dev); 3370 if (error) 3371 goto SysEntryError; 3372 3373 devtmpfs_create_node(dev); 3374 } 3375 3376 /* Notify clients of device addition. This call must come 3377 * after dpm_sysfs_add() and before kobject_uevent(). 3378 */ 3379 if (dev->bus) 3380 blocking_notifier_call_chain(&dev->bus->p->bus_notifier, 3381 BUS_NOTIFY_ADD_DEVICE, dev); 3382 3383 kobject_uevent(&dev->kobj, KOBJ_ADD); 3384 3385 /* 3386 * Check if any of the other devices (consumers) have been waiting for 3387 * this device (supplier) to be added so that they can create a device 3388 * link to it. 3389 * 3390 * This needs to happen after device_pm_add() because device_link_add() 3391 * requires the supplier be registered before it's called. 3392 * 3393 * But this also needs to happen before bus_probe_device() to make sure 3394 * waiting consumers can link to it before the driver is bound to the 3395 * device and the driver sync_state callback is called for this device. 3396 */ 3397 if (dev->fwnode && !dev->fwnode->dev) { 3398 dev->fwnode->dev = dev; 3399 fw_devlink_link_device(dev); 3400 } 3401 3402 bus_probe_device(dev); 3403 3404 /* 3405 * If all driver registration is done and a newly added device doesn't 3406 * match with any driver, don't block its consumers from probing in 3407 * case the consumer device is able to operate without this supplier. 3408 */ 3409 if (dev->fwnode && fw_devlink_drv_reg_done && !dev->can_match) 3410 fw_devlink_unblock_consumers(dev); 3411 3412 if (parent) 3413 klist_add_tail(&dev->p->knode_parent, 3414 &parent->p->klist_children); 3415 3416 if (dev->class) { 3417 mutex_lock(&dev->class->p->mutex); 3418 /* tie the class to the device */ 3419 klist_add_tail(&dev->p->knode_class, 3420 &dev->class->p->klist_devices); 3421 3422 /* notify any interfaces that the device is here */ 3423 list_for_each_entry(class_intf, 3424 &dev->class->p->interfaces, node) 3425 if (class_intf->add_dev) 3426 class_intf->add_dev(dev, class_intf); 3427 mutex_unlock(&dev->class->p->mutex); 3428 } 3429 done: 3430 put_device(dev); 3431 return error; 3432 SysEntryError: 3433 if (MAJOR(dev->devt)) 3434 device_remove_file(dev, &dev_attr_dev); 3435 DevAttrError: 3436 device_pm_remove(dev); 3437 dpm_sysfs_remove(dev); 3438 DPMError: 3439 bus_remove_device(dev); 3440 BusError: 3441 device_remove_attrs(dev); 3442 AttrsError: 3443 device_remove_class_symlinks(dev); 3444 SymlinkError: 3445 device_remove_file(dev, &dev_attr_uevent); 3446 attrError: 3447 device_platform_notify_remove(dev); 3448 kobject_uevent(&dev->kobj, KOBJ_REMOVE); 3449 glue_dir = get_glue_dir(dev); 3450 kobject_del(&dev->kobj); 3451 Error: 3452 cleanup_glue_dir(dev, glue_dir); 3453 parent_error: 3454 put_device(parent); 3455 name_error: 3456 kfree(dev->p); 3457 dev->p = NULL; 3458 goto done; 3459 } 3460 EXPORT_SYMBOL_GPL(device_add); 3461 3462 /** 3463 * device_register - register a device with the system. 3464 * @dev: pointer to the device structure 3465 * 3466 * This happens in two clean steps - initialize the device 3467 * and add it to the system. The two steps can be called 3468 * separately, but this is the easiest and most common. 3469 * I.e. you should only call the two helpers separately if 3470 * have a clearly defined need to use and refcount the device 3471 * before it is added to the hierarchy. 3472 * 3473 * For more information, see the kerneldoc for device_initialize() 3474 * and device_add(). 3475 * 3476 * NOTE: _Never_ directly free @dev after calling this function, even 3477 * if it returned an error! Always use put_device() to give up the 3478 * reference initialized in this function instead. 3479 */ 3480 int device_register(struct device *dev) 3481 { 3482 device_initialize(dev); 3483 return device_add(dev); 3484 } 3485 EXPORT_SYMBOL_GPL(device_register); 3486 3487 /** 3488 * get_device - increment reference count for device. 3489 * @dev: device. 3490 * 3491 * This simply forwards the call to kobject_get(), though 3492 * we do take care to provide for the case that we get a NULL 3493 * pointer passed in. 3494 */ 3495 struct device *get_device(struct device *dev) 3496 { 3497 return dev ? kobj_to_dev(kobject_get(&dev->kobj)) : NULL; 3498 } 3499 EXPORT_SYMBOL_GPL(get_device); 3500 3501 /** 3502 * put_device - decrement reference count. 3503 * @dev: device in question. 3504 */ 3505 void put_device(struct device *dev) 3506 { 3507 /* might_sleep(); */ 3508 if (dev) 3509 kobject_put(&dev->kobj); 3510 } 3511 EXPORT_SYMBOL_GPL(put_device); 3512 3513 bool kill_device(struct device *dev) 3514 { 3515 /* 3516 * Require the device lock and set the "dead" flag to guarantee that 3517 * the update behavior is consistent with the other bitfields near 3518 * it and that we cannot have an asynchronous probe routine trying 3519 * to run while we are tearing out the bus/class/sysfs from 3520 * underneath the device. 3521 */ 3522 device_lock_assert(dev); 3523 3524 if (dev->p->dead) 3525 return false; 3526 dev->p->dead = true; 3527 return true; 3528 } 3529 EXPORT_SYMBOL_GPL(kill_device); 3530 3531 /** 3532 * device_del - delete device from system. 3533 * @dev: device. 3534 * 3535 * This is the first part of the device unregistration 3536 * sequence. This removes the device from the lists we control 3537 * from here, has it removed from the other driver model 3538 * subsystems it was added to in device_add(), and removes it 3539 * from the kobject hierarchy. 3540 * 3541 * NOTE: this should be called manually _iff_ device_add() was 3542 * also called manually. 3543 */ 3544 void device_del(struct device *dev) 3545 { 3546 struct device *parent = dev->parent; 3547 struct kobject *glue_dir = NULL; 3548 struct class_interface *class_intf; 3549 unsigned int noio_flag; 3550 3551 device_lock(dev); 3552 kill_device(dev); 3553 device_unlock(dev); 3554 3555 if (dev->fwnode && dev->fwnode->dev == dev) 3556 dev->fwnode->dev = NULL; 3557 3558 /* Notify clients of device removal. This call must come 3559 * before dpm_sysfs_remove(). 3560 */ 3561 noio_flag = memalloc_noio_save(); 3562 if (dev->bus) 3563 blocking_notifier_call_chain(&dev->bus->p->bus_notifier, 3564 BUS_NOTIFY_DEL_DEVICE, dev); 3565 3566 dpm_sysfs_remove(dev); 3567 if (parent) 3568 klist_del(&dev->p->knode_parent); 3569 if (MAJOR(dev->devt)) { 3570 devtmpfs_delete_node(dev); 3571 device_remove_sys_dev_entry(dev); 3572 device_remove_file(dev, &dev_attr_dev); 3573 } 3574 if (dev->class) { 3575 device_remove_class_symlinks(dev); 3576 3577 mutex_lock(&dev->class->p->mutex); 3578 /* notify any interfaces that the device is now gone */ 3579 list_for_each_entry(class_intf, 3580 &dev->class->p->interfaces, node) 3581 if (class_intf->remove_dev) 3582 class_intf->remove_dev(dev, class_intf); 3583 /* remove the device from the class list */ 3584 klist_del(&dev->p->knode_class); 3585 mutex_unlock(&dev->class->p->mutex); 3586 } 3587 device_remove_file(dev, &dev_attr_uevent); 3588 device_remove_attrs(dev); 3589 bus_remove_device(dev); 3590 device_pm_remove(dev); 3591 driver_deferred_probe_del(dev); 3592 device_platform_notify_remove(dev); 3593 device_links_purge(dev); 3594 3595 if (dev->bus) 3596 blocking_notifier_call_chain(&dev->bus->p->bus_notifier, 3597 BUS_NOTIFY_REMOVED_DEVICE, dev); 3598 kobject_uevent(&dev->kobj, KOBJ_REMOVE); 3599 glue_dir = get_glue_dir(dev); 3600 kobject_del(&dev->kobj); 3601 cleanup_glue_dir(dev, glue_dir); 3602 memalloc_noio_restore(noio_flag); 3603 put_device(parent); 3604 } 3605 EXPORT_SYMBOL_GPL(device_del); 3606 3607 /** 3608 * device_unregister - unregister device from system. 3609 * @dev: device going away. 3610 * 3611 * We do this in two parts, like we do device_register(). First, 3612 * we remove it from all the subsystems with device_del(), then 3613 * we decrement the reference count via put_device(). If that 3614 * is the final reference count, the device will be cleaned up 3615 * via device_release() above. Otherwise, the structure will 3616 * stick around until the final reference to the device is dropped. 3617 */ 3618 void device_unregister(struct device *dev) 3619 { 3620 pr_debug("device: '%s': %s\n", dev_name(dev), __func__); 3621 device_del(dev); 3622 put_device(dev); 3623 } 3624 EXPORT_SYMBOL_GPL(device_unregister); 3625 3626 static struct device *prev_device(struct klist_iter *i) 3627 { 3628 struct klist_node *n = klist_prev(i); 3629 struct device *dev = NULL; 3630 struct device_private *p; 3631 3632 if (n) { 3633 p = to_device_private_parent(n); 3634 dev = p->device; 3635 } 3636 return dev; 3637 } 3638 3639 static struct device *next_device(struct klist_iter *i) 3640 { 3641 struct klist_node *n = klist_next(i); 3642 struct device *dev = NULL; 3643 struct device_private *p; 3644 3645 if (n) { 3646 p = to_device_private_parent(n); 3647 dev = p->device; 3648 } 3649 return dev; 3650 } 3651 3652 /** 3653 * device_get_devnode - path of device node file 3654 * @dev: device 3655 * @mode: returned file access mode 3656 * @uid: returned file owner 3657 * @gid: returned file group 3658 * @tmp: possibly allocated string 3659 * 3660 * Return the relative path of a possible device node. 3661 * Non-default names may need to allocate a memory to compose 3662 * a name. This memory is returned in tmp and needs to be 3663 * freed by the caller. 3664 */ 3665 const char *device_get_devnode(struct device *dev, 3666 umode_t *mode, kuid_t *uid, kgid_t *gid, 3667 const char **tmp) 3668 { 3669 char *s; 3670 3671 *tmp = NULL; 3672 3673 /* the device type may provide a specific name */ 3674 if (dev->type && dev->type->devnode) 3675 *tmp = dev->type->devnode(dev, mode, uid, gid); 3676 if (*tmp) 3677 return *tmp; 3678 3679 /* the class may provide a specific name */ 3680 if (dev->class && dev->class->devnode) 3681 *tmp = dev->class->devnode(dev, mode); 3682 if (*tmp) 3683 return *tmp; 3684 3685 /* return name without allocation, tmp == NULL */ 3686 if (strchr(dev_name(dev), '!') == NULL) 3687 return dev_name(dev); 3688 3689 /* replace '!' in the name with '/' */ 3690 s = kstrdup(dev_name(dev), GFP_KERNEL); 3691 if (!s) 3692 return NULL; 3693 strreplace(s, '!', '/'); 3694 return *tmp = s; 3695 } 3696 3697 /** 3698 * device_for_each_child - device child iterator. 3699 * @parent: parent struct device. 3700 * @fn: function to be called for each device. 3701 * @data: data for the callback. 3702 * 3703 * Iterate over @parent's child devices, and call @fn for each, 3704 * passing it @data. 3705 * 3706 * We check the return of @fn each time. If it returns anything 3707 * other than 0, we break out and return that value. 3708 */ 3709 int device_for_each_child(struct device *parent, void *data, 3710 int (*fn)(struct device *dev, void *data)) 3711 { 3712 struct klist_iter i; 3713 struct device *child; 3714 int error = 0; 3715 3716 if (!parent->p) 3717 return 0; 3718 3719 klist_iter_init(&parent->p->klist_children, &i); 3720 while (!error && (child = next_device(&i))) 3721 error = fn(child, data); 3722 klist_iter_exit(&i); 3723 return error; 3724 } 3725 EXPORT_SYMBOL_GPL(device_for_each_child); 3726 3727 /** 3728 * device_for_each_child_reverse - device child iterator in reversed order. 3729 * @parent: parent struct device. 3730 * @fn: function to be called for each device. 3731 * @data: data for the callback. 3732 * 3733 * Iterate over @parent's child devices, and call @fn for each, 3734 * passing it @data. 3735 * 3736 * We check the return of @fn each time. If it returns anything 3737 * other than 0, we break out and return that value. 3738 */ 3739 int device_for_each_child_reverse(struct device *parent, void *data, 3740 int (*fn)(struct device *dev, void *data)) 3741 { 3742 struct klist_iter i; 3743 struct device *child; 3744 int error = 0; 3745 3746 if (!parent->p) 3747 return 0; 3748 3749 klist_iter_init(&parent->p->klist_children, &i); 3750 while ((child = prev_device(&i)) && !error) 3751 error = fn(child, data); 3752 klist_iter_exit(&i); 3753 return error; 3754 } 3755 EXPORT_SYMBOL_GPL(device_for_each_child_reverse); 3756 3757 /** 3758 * device_find_child - device iterator for locating a particular device. 3759 * @parent: parent struct device 3760 * @match: Callback function to check device 3761 * @data: Data to pass to match function 3762 * 3763 * This is similar to the device_for_each_child() function above, but it 3764 * returns a reference to a device that is 'found' for later use, as 3765 * determined by the @match callback. 3766 * 3767 * The callback should return 0 if the device doesn't match and non-zero 3768 * if it does. If the callback returns non-zero and a reference to the 3769 * current device can be obtained, this function will return to the caller 3770 * and not iterate over any more devices. 3771 * 3772 * NOTE: you will need to drop the reference with put_device() after use. 3773 */ 3774 struct device *device_find_child(struct device *parent, void *data, 3775 int (*match)(struct device *dev, void *data)) 3776 { 3777 struct klist_iter i; 3778 struct device *child; 3779 3780 if (!parent) 3781 return NULL; 3782 3783 klist_iter_init(&parent->p->klist_children, &i); 3784 while ((child = next_device(&i))) 3785 if (match(child, data) && get_device(child)) 3786 break; 3787 klist_iter_exit(&i); 3788 return child; 3789 } 3790 EXPORT_SYMBOL_GPL(device_find_child); 3791 3792 /** 3793 * device_find_child_by_name - device iterator for locating a child device. 3794 * @parent: parent struct device 3795 * @name: name of the child device 3796 * 3797 * This is similar to the device_find_child() function above, but it 3798 * returns a reference to a device that has the name @name. 3799 * 3800 * NOTE: you will need to drop the reference with put_device() after use. 3801 */ 3802 struct device *device_find_child_by_name(struct device *parent, 3803 const char *name) 3804 { 3805 struct klist_iter i; 3806 struct device *child; 3807 3808 if (!parent) 3809 return NULL; 3810 3811 klist_iter_init(&parent->p->klist_children, &i); 3812 while ((child = next_device(&i))) 3813 if (sysfs_streq(dev_name(child), name) && get_device(child)) 3814 break; 3815 klist_iter_exit(&i); 3816 return child; 3817 } 3818 EXPORT_SYMBOL_GPL(device_find_child_by_name); 3819 3820 int __init devices_init(void) 3821 { 3822 devices_kset = kset_create_and_add("devices", &device_uevent_ops, NULL); 3823 if (!devices_kset) 3824 return -ENOMEM; 3825 dev_kobj = kobject_create_and_add("dev", NULL); 3826 if (!dev_kobj) 3827 goto dev_kobj_err; 3828 sysfs_dev_block_kobj = kobject_create_and_add("block", dev_kobj); 3829 if (!sysfs_dev_block_kobj) 3830 goto block_kobj_err; 3831 sysfs_dev_char_kobj = kobject_create_and_add("char", dev_kobj); 3832 if (!sysfs_dev_char_kobj) 3833 goto char_kobj_err; 3834 3835 return 0; 3836 3837 char_kobj_err: 3838 kobject_put(sysfs_dev_block_kobj); 3839 block_kobj_err: 3840 kobject_put(dev_kobj); 3841 dev_kobj_err: 3842 kset_unregister(devices_kset); 3843 return -ENOMEM; 3844 } 3845 3846 static int device_check_offline(struct device *dev, void *not_used) 3847 { 3848 int ret; 3849 3850 ret = device_for_each_child(dev, NULL, device_check_offline); 3851 if (ret) 3852 return ret; 3853 3854 return device_supports_offline(dev) && !dev->offline ? -EBUSY : 0; 3855 } 3856 3857 /** 3858 * device_offline - Prepare the device for hot-removal. 3859 * @dev: Device to be put offline. 3860 * 3861 * Execute the device bus type's .offline() callback, if present, to prepare 3862 * the device for a subsequent hot-removal. If that succeeds, the device must 3863 * not be used until either it is removed or its bus type's .online() callback 3864 * is executed. 3865 * 3866 * Call under device_hotplug_lock. 3867 */ 3868 int device_offline(struct device *dev) 3869 { 3870 int ret; 3871 3872 if (dev->offline_disabled) 3873 return -EPERM; 3874 3875 ret = device_for_each_child(dev, NULL, device_check_offline); 3876 if (ret) 3877 return ret; 3878 3879 device_lock(dev); 3880 if (device_supports_offline(dev)) { 3881 if (dev->offline) { 3882 ret = 1; 3883 } else { 3884 ret = dev->bus->offline(dev); 3885 if (!ret) { 3886 kobject_uevent(&dev->kobj, KOBJ_OFFLINE); 3887 dev->offline = true; 3888 } 3889 } 3890 } 3891 device_unlock(dev); 3892 3893 return ret; 3894 } 3895 3896 /** 3897 * device_online - Put the device back online after successful device_offline(). 3898 * @dev: Device to be put back online. 3899 * 3900 * If device_offline() has been successfully executed for @dev, but the device 3901 * has not been removed subsequently, execute its bus type's .online() callback 3902 * to indicate that the device can be used again. 3903 * 3904 * Call under device_hotplug_lock. 3905 */ 3906 int device_online(struct device *dev) 3907 { 3908 int ret = 0; 3909 3910 device_lock(dev); 3911 if (device_supports_offline(dev)) { 3912 if (dev->offline) { 3913 ret = dev->bus->online(dev); 3914 if (!ret) { 3915 kobject_uevent(&dev->kobj, KOBJ_ONLINE); 3916 dev->offline = false; 3917 } 3918 } else { 3919 ret = 1; 3920 } 3921 } 3922 device_unlock(dev); 3923 3924 return ret; 3925 } 3926 3927 struct root_device { 3928 struct device dev; 3929 struct module *owner; 3930 }; 3931 3932 static inline struct root_device *to_root_device(struct device *d) 3933 { 3934 return container_of(d, struct root_device, dev); 3935 } 3936 3937 static void root_device_release(struct device *dev) 3938 { 3939 kfree(to_root_device(dev)); 3940 } 3941 3942 /** 3943 * __root_device_register - allocate and register a root device 3944 * @name: root device name 3945 * @owner: owner module of the root device, usually THIS_MODULE 3946 * 3947 * This function allocates a root device and registers it 3948 * using device_register(). In order to free the returned 3949 * device, use root_device_unregister(). 3950 * 3951 * Root devices are dummy devices which allow other devices 3952 * to be grouped under /sys/devices. Use this function to 3953 * allocate a root device and then use it as the parent of 3954 * any device which should appear under /sys/devices/{name} 3955 * 3956 * The /sys/devices/{name} directory will also contain a 3957 * 'module' symlink which points to the @owner directory 3958 * in sysfs. 3959 * 3960 * Returns &struct device pointer on success, or ERR_PTR() on error. 3961 * 3962 * Note: You probably want to use root_device_register(). 3963 */ 3964 struct device *__root_device_register(const char *name, struct module *owner) 3965 { 3966 struct root_device *root; 3967 int err = -ENOMEM; 3968 3969 root = kzalloc(sizeof(struct root_device), GFP_KERNEL); 3970 if (!root) 3971 return ERR_PTR(err); 3972 3973 err = dev_set_name(&root->dev, "%s", name); 3974 if (err) { 3975 kfree(root); 3976 return ERR_PTR(err); 3977 } 3978 3979 root->dev.release = root_device_release; 3980 3981 err = device_register(&root->dev); 3982 if (err) { 3983 put_device(&root->dev); 3984 return ERR_PTR(err); 3985 } 3986 3987 #ifdef CONFIG_MODULES /* gotta find a "cleaner" way to do this */ 3988 if (owner) { 3989 struct module_kobject *mk = &owner->mkobj; 3990 3991 err = sysfs_create_link(&root->dev.kobj, &mk->kobj, "module"); 3992 if (err) { 3993 device_unregister(&root->dev); 3994 return ERR_PTR(err); 3995 } 3996 root->owner = owner; 3997 } 3998 #endif 3999 4000 return &root->dev; 4001 } 4002 EXPORT_SYMBOL_GPL(__root_device_register); 4003 4004 /** 4005 * root_device_unregister - unregister and free a root device 4006 * @dev: device going away 4007 * 4008 * This function unregisters and cleans up a device that was created by 4009 * root_device_register(). 4010 */ 4011 void root_device_unregister(struct device *dev) 4012 { 4013 struct root_device *root = to_root_device(dev); 4014 4015 if (root->owner) 4016 sysfs_remove_link(&root->dev.kobj, "module"); 4017 4018 device_unregister(dev); 4019 } 4020 EXPORT_SYMBOL_GPL(root_device_unregister); 4021 4022 4023 static void device_create_release(struct device *dev) 4024 { 4025 pr_debug("device: '%s': %s\n", dev_name(dev), __func__); 4026 kfree(dev); 4027 } 4028 4029 static __printf(6, 0) struct device * 4030 device_create_groups_vargs(struct class *class, struct device *parent, 4031 dev_t devt, void *drvdata, 4032 const struct attribute_group **groups, 4033 const char *fmt, va_list args) 4034 { 4035 struct device *dev = NULL; 4036 int retval = -ENODEV; 4037 4038 if (class == NULL || IS_ERR(class)) 4039 goto error; 4040 4041 dev = kzalloc(sizeof(*dev), GFP_KERNEL); 4042 if (!dev) { 4043 retval = -ENOMEM; 4044 goto error; 4045 } 4046 4047 device_initialize(dev); 4048 dev->devt = devt; 4049 dev->class = class; 4050 dev->parent = parent; 4051 dev->groups = groups; 4052 dev->release = device_create_release; 4053 dev_set_drvdata(dev, drvdata); 4054 4055 retval = kobject_set_name_vargs(&dev->kobj, fmt, args); 4056 if (retval) 4057 goto error; 4058 4059 retval = device_add(dev); 4060 if (retval) 4061 goto error; 4062 4063 return dev; 4064 4065 error: 4066 put_device(dev); 4067 return ERR_PTR(retval); 4068 } 4069 4070 /** 4071 * device_create - creates a device and registers it with sysfs 4072 * @class: pointer to the struct class that this device should be registered to 4073 * @parent: pointer to the parent struct device of this new device, if any 4074 * @devt: the dev_t for the char device to be added 4075 * @drvdata: the data to be added to the device for callbacks 4076 * @fmt: string for the device's name 4077 * 4078 * This function can be used by char device classes. A struct device 4079 * will be created in sysfs, registered to the specified class. 4080 * 4081 * A "dev" file will be created, showing the dev_t for the device, if 4082 * the dev_t is not 0,0. 4083 * If a pointer to a parent struct device is passed in, the newly created 4084 * struct device will be a child of that device in sysfs. 4085 * The pointer to the struct device will be returned from the call. 4086 * Any further sysfs files that might be required can be created using this 4087 * pointer. 4088 * 4089 * Returns &struct device pointer on success, or ERR_PTR() on error. 4090 * 4091 * Note: the struct class passed to this function must have previously 4092 * been created with a call to class_create(). 4093 */ 4094 struct device *device_create(struct class *class, struct device *parent, 4095 dev_t devt, void *drvdata, const char *fmt, ...) 4096 { 4097 va_list vargs; 4098 struct device *dev; 4099 4100 va_start(vargs, fmt); 4101 dev = device_create_groups_vargs(class, parent, devt, drvdata, NULL, 4102 fmt, vargs); 4103 va_end(vargs); 4104 return dev; 4105 } 4106 EXPORT_SYMBOL_GPL(device_create); 4107 4108 /** 4109 * device_create_with_groups - creates a device and registers it with sysfs 4110 * @class: pointer to the struct class that this device should be registered to 4111 * @parent: pointer to the parent struct device of this new device, if any 4112 * @devt: the dev_t for the char device to be added 4113 * @drvdata: the data to be added to the device for callbacks 4114 * @groups: NULL-terminated list of attribute groups to be created 4115 * @fmt: string for the device's name 4116 * 4117 * This function can be used by char device classes. A struct device 4118 * will be created in sysfs, registered to the specified class. 4119 * Additional attributes specified in the groups parameter will also 4120 * be created automatically. 4121 * 4122 * A "dev" file will be created, showing the dev_t for the device, if 4123 * the dev_t is not 0,0. 4124 * If a pointer to a parent struct device is passed in, the newly created 4125 * struct device will be a child of that device in sysfs. 4126 * The pointer to the struct device will be returned from the call. 4127 * Any further sysfs files that might be required can be created using this 4128 * pointer. 4129 * 4130 * Returns &struct device pointer on success, or ERR_PTR() on error. 4131 * 4132 * Note: the struct class passed to this function must have previously 4133 * been created with a call to class_create(). 4134 */ 4135 struct device *device_create_with_groups(struct class *class, 4136 struct device *parent, dev_t devt, 4137 void *drvdata, 4138 const struct attribute_group **groups, 4139 const char *fmt, ...) 4140 { 4141 va_list vargs; 4142 struct device *dev; 4143 4144 va_start(vargs, fmt); 4145 dev = device_create_groups_vargs(class, parent, devt, drvdata, groups, 4146 fmt, vargs); 4147 va_end(vargs); 4148 return dev; 4149 } 4150 EXPORT_SYMBOL_GPL(device_create_with_groups); 4151 4152 /** 4153 * device_destroy - removes a device that was created with device_create() 4154 * @class: pointer to the struct class that this device was registered with 4155 * @devt: the dev_t of the device that was previously registered 4156 * 4157 * This call unregisters and cleans up a device that was created with a 4158 * call to device_create(). 4159 */ 4160 void device_destroy(struct class *class, dev_t devt) 4161 { 4162 struct device *dev; 4163 4164 dev = class_find_device_by_devt(class, devt); 4165 if (dev) { 4166 put_device(dev); 4167 device_unregister(dev); 4168 } 4169 } 4170 EXPORT_SYMBOL_GPL(device_destroy); 4171 4172 /** 4173 * device_rename - renames a device 4174 * @dev: the pointer to the struct device to be renamed 4175 * @new_name: the new name of the device 4176 * 4177 * It is the responsibility of the caller to provide mutual 4178 * exclusion between two different calls of device_rename 4179 * on the same device to ensure that new_name is valid and 4180 * won't conflict with other devices. 4181 * 4182 * Note: Don't call this function. Currently, the networking layer calls this 4183 * function, but that will change. The following text from Kay Sievers offers 4184 * some insight: 4185 * 4186 * Renaming devices is racy at many levels, symlinks and other stuff are not 4187 * replaced atomically, and you get a "move" uevent, but it's not easy to 4188 * connect the event to the old and new device. Device nodes are not renamed at 4189 * all, there isn't even support for that in the kernel now. 4190 * 4191 * In the meantime, during renaming, your target name might be taken by another 4192 * driver, creating conflicts. Or the old name is taken directly after you 4193 * renamed it -- then you get events for the same DEVPATH, before you even see 4194 * the "move" event. It's just a mess, and nothing new should ever rely on 4195 * kernel device renaming. Besides that, it's not even implemented now for 4196 * other things than (driver-core wise very simple) network devices. 4197 * 4198 * We are currently about to change network renaming in udev to completely 4199 * disallow renaming of devices in the same namespace as the kernel uses, 4200 * because we can't solve the problems properly, that arise with swapping names 4201 * of multiple interfaces without races. Means, renaming of eth[0-9]* will only 4202 * be allowed to some other name than eth[0-9]*, for the aforementioned 4203 * reasons. 4204 * 4205 * Make up a "real" name in the driver before you register anything, or add 4206 * some other attributes for userspace to find the device, or use udev to add 4207 * symlinks -- but never rename kernel devices later, it's a complete mess. We 4208 * don't even want to get into that and try to implement the missing pieces in 4209 * the core. We really have other pieces to fix in the driver core mess. :) 4210 */ 4211 int device_rename(struct device *dev, const char *new_name) 4212 { 4213 struct kobject *kobj = &dev->kobj; 4214 char *old_device_name = NULL; 4215 int error; 4216 4217 dev = get_device(dev); 4218 if (!dev) 4219 return -EINVAL; 4220 4221 dev_dbg(dev, "renaming to %s\n", new_name); 4222 4223 old_device_name = kstrdup(dev_name(dev), GFP_KERNEL); 4224 if (!old_device_name) { 4225 error = -ENOMEM; 4226 goto out; 4227 } 4228 4229 if (dev->class) { 4230 error = sysfs_rename_link_ns(&dev->class->p->subsys.kobj, 4231 kobj, old_device_name, 4232 new_name, kobject_namespace(kobj)); 4233 if (error) 4234 goto out; 4235 } 4236 4237 error = kobject_rename(kobj, new_name); 4238 if (error) 4239 goto out; 4240 4241 out: 4242 put_device(dev); 4243 4244 kfree(old_device_name); 4245 4246 return error; 4247 } 4248 EXPORT_SYMBOL_GPL(device_rename); 4249 4250 static int device_move_class_links(struct device *dev, 4251 struct device *old_parent, 4252 struct device *new_parent) 4253 { 4254 int error = 0; 4255 4256 if (old_parent) 4257 sysfs_remove_link(&dev->kobj, "device"); 4258 if (new_parent) 4259 error = sysfs_create_link(&dev->kobj, &new_parent->kobj, 4260 "device"); 4261 return error; 4262 } 4263 4264 /** 4265 * device_move - moves a device to a new parent 4266 * @dev: the pointer to the struct device to be moved 4267 * @new_parent: the new parent of the device (can be NULL) 4268 * @dpm_order: how to reorder the dpm_list 4269 */ 4270 int device_move(struct device *dev, struct device *new_parent, 4271 enum dpm_order dpm_order) 4272 { 4273 int error; 4274 struct device *old_parent; 4275 struct kobject *new_parent_kobj; 4276 4277 dev = get_device(dev); 4278 if (!dev) 4279 return -EINVAL; 4280 4281 device_pm_lock(); 4282 new_parent = get_device(new_parent); 4283 new_parent_kobj = get_device_parent(dev, new_parent); 4284 if (IS_ERR(new_parent_kobj)) { 4285 error = PTR_ERR(new_parent_kobj); 4286 put_device(new_parent); 4287 goto out; 4288 } 4289 4290 pr_debug("device: '%s': %s: moving to '%s'\n", dev_name(dev), 4291 __func__, new_parent ? dev_name(new_parent) : "<NULL>"); 4292 error = kobject_move(&dev->kobj, new_parent_kobj); 4293 if (error) { 4294 cleanup_glue_dir(dev, new_parent_kobj); 4295 put_device(new_parent); 4296 goto out; 4297 } 4298 old_parent = dev->parent; 4299 dev->parent = new_parent; 4300 if (old_parent) 4301 klist_remove(&dev->p->knode_parent); 4302 if (new_parent) { 4303 klist_add_tail(&dev->p->knode_parent, 4304 &new_parent->p->klist_children); 4305 set_dev_node(dev, dev_to_node(new_parent)); 4306 } 4307 4308 if (dev->class) { 4309 error = device_move_class_links(dev, old_parent, new_parent); 4310 if (error) { 4311 /* We ignore errors on cleanup since we're hosed anyway... */ 4312 device_move_class_links(dev, new_parent, old_parent); 4313 if (!kobject_move(&dev->kobj, &old_parent->kobj)) { 4314 if (new_parent) 4315 klist_remove(&dev->p->knode_parent); 4316 dev->parent = old_parent; 4317 if (old_parent) { 4318 klist_add_tail(&dev->p->knode_parent, 4319 &old_parent->p->klist_children); 4320 set_dev_node(dev, dev_to_node(old_parent)); 4321 } 4322 } 4323 cleanup_glue_dir(dev, new_parent_kobj); 4324 put_device(new_parent); 4325 goto out; 4326 } 4327 } 4328 switch (dpm_order) { 4329 case DPM_ORDER_NONE: 4330 break; 4331 case DPM_ORDER_DEV_AFTER_PARENT: 4332 device_pm_move_after(dev, new_parent); 4333 devices_kset_move_after(dev, new_parent); 4334 break; 4335 case DPM_ORDER_PARENT_BEFORE_DEV: 4336 device_pm_move_before(new_parent, dev); 4337 devices_kset_move_before(new_parent, dev); 4338 break; 4339 case DPM_ORDER_DEV_LAST: 4340 device_pm_move_last(dev); 4341 devices_kset_move_last(dev); 4342 break; 4343 } 4344 4345 put_device(old_parent); 4346 out: 4347 device_pm_unlock(); 4348 put_device(dev); 4349 return error; 4350 } 4351 EXPORT_SYMBOL_GPL(device_move); 4352 4353 static int device_attrs_change_owner(struct device *dev, kuid_t kuid, 4354 kgid_t kgid) 4355 { 4356 struct kobject *kobj = &dev->kobj; 4357 struct class *class = dev->class; 4358 const struct device_type *type = dev->type; 4359 int error; 4360 4361 if (class) { 4362 /* 4363 * Change the device groups of the device class for @dev to 4364 * @kuid/@kgid. 4365 */ 4366 error = sysfs_groups_change_owner(kobj, class->dev_groups, kuid, 4367 kgid); 4368 if (error) 4369 return error; 4370 } 4371 4372 if (type) { 4373 /* 4374 * Change the device groups of the device type for @dev to 4375 * @kuid/@kgid. 4376 */ 4377 error = sysfs_groups_change_owner(kobj, type->groups, kuid, 4378 kgid); 4379 if (error) 4380 return error; 4381 } 4382 4383 /* Change the device groups of @dev to @kuid/@kgid. */ 4384 error = sysfs_groups_change_owner(kobj, dev->groups, kuid, kgid); 4385 if (error) 4386 return error; 4387 4388 if (device_supports_offline(dev) && !dev->offline_disabled) { 4389 /* Change online device attributes of @dev to @kuid/@kgid. */ 4390 error = sysfs_file_change_owner(kobj, dev_attr_online.attr.name, 4391 kuid, kgid); 4392 if (error) 4393 return error; 4394 } 4395 4396 return 0; 4397 } 4398 4399 /** 4400 * device_change_owner - change the owner of an existing device. 4401 * @dev: device. 4402 * @kuid: new owner's kuid 4403 * @kgid: new owner's kgid 4404 * 4405 * This changes the owner of @dev and its corresponding sysfs entries to 4406 * @kuid/@kgid. This function closely mirrors how @dev was added via driver 4407 * core. 4408 * 4409 * Returns 0 on success or error code on failure. 4410 */ 4411 int device_change_owner(struct device *dev, kuid_t kuid, kgid_t kgid) 4412 { 4413 int error; 4414 struct kobject *kobj = &dev->kobj; 4415 4416 dev = get_device(dev); 4417 if (!dev) 4418 return -EINVAL; 4419 4420 /* 4421 * Change the kobject and the default attributes and groups of the 4422 * ktype associated with it to @kuid/@kgid. 4423 */ 4424 error = sysfs_change_owner(kobj, kuid, kgid); 4425 if (error) 4426 goto out; 4427 4428 /* 4429 * Change the uevent file for @dev to the new owner. The uevent file 4430 * was created in a separate step when @dev got added and we mirror 4431 * that step here. 4432 */ 4433 error = sysfs_file_change_owner(kobj, dev_attr_uevent.attr.name, kuid, 4434 kgid); 4435 if (error) 4436 goto out; 4437 4438 /* 4439 * Change the device groups, the device groups associated with the 4440 * device class, and the groups associated with the device type of @dev 4441 * to @kuid/@kgid. 4442 */ 4443 error = device_attrs_change_owner(dev, kuid, kgid); 4444 if (error) 4445 goto out; 4446 4447 error = dpm_sysfs_change_owner(dev, kuid, kgid); 4448 if (error) 4449 goto out; 4450 4451 #ifdef CONFIG_BLOCK 4452 if (sysfs_deprecated && dev->class == &block_class) 4453 goto out; 4454 #endif 4455 4456 /* 4457 * Change the owner of the symlink located in the class directory of 4458 * the device class associated with @dev which points to the actual 4459 * directory entry for @dev to @kuid/@kgid. This ensures that the 4460 * symlink shows the same permissions as its target. 4461 */ 4462 error = sysfs_link_change_owner(&dev->class->p->subsys.kobj, &dev->kobj, 4463 dev_name(dev), kuid, kgid); 4464 if (error) 4465 goto out; 4466 4467 out: 4468 put_device(dev); 4469 return error; 4470 } 4471 EXPORT_SYMBOL_GPL(device_change_owner); 4472 4473 /** 4474 * device_shutdown - call ->shutdown() on each device to shutdown. 4475 */ 4476 void device_shutdown(void) 4477 { 4478 struct device *dev, *parent; 4479 4480 wait_for_device_probe(); 4481 device_block_probing(); 4482 4483 cpufreq_suspend(); 4484 4485 spin_lock(&devices_kset->list_lock); 4486 /* 4487 * Walk the devices list backward, shutting down each in turn. 4488 * Beware that device unplug events may also start pulling 4489 * devices offline, even as the system is shutting down. 4490 */ 4491 while (!list_empty(&devices_kset->list)) { 4492 dev = list_entry(devices_kset->list.prev, struct device, 4493 kobj.entry); 4494 4495 /* 4496 * hold reference count of device's parent to 4497 * prevent it from being freed because parent's 4498 * lock is to be held 4499 */ 4500 parent = get_device(dev->parent); 4501 get_device(dev); 4502 /* 4503 * Make sure the device is off the kset list, in the 4504 * event that dev->*->shutdown() doesn't remove it. 4505 */ 4506 list_del_init(&dev->kobj.entry); 4507 spin_unlock(&devices_kset->list_lock); 4508 4509 /* hold lock to avoid race with probe/release */ 4510 if (parent) 4511 device_lock(parent); 4512 device_lock(dev); 4513 4514 /* Don't allow any more runtime suspends */ 4515 pm_runtime_get_noresume(dev); 4516 pm_runtime_barrier(dev); 4517 4518 if (dev->class && dev->class->shutdown_pre) { 4519 if (initcall_debug) 4520 dev_info(dev, "shutdown_pre\n"); 4521 dev->class->shutdown_pre(dev); 4522 } 4523 if (dev->bus && dev->bus->shutdown) { 4524 if (initcall_debug) 4525 dev_info(dev, "shutdown\n"); 4526 dev->bus->shutdown(dev); 4527 } else if (dev->driver && dev->driver->shutdown) { 4528 if (initcall_debug) 4529 dev_info(dev, "shutdown\n"); 4530 dev->driver->shutdown(dev); 4531 } 4532 4533 device_unlock(dev); 4534 if (parent) 4535 device_unlock(parent); 4536 4537 put_device(dev); 4538 put_device(parent); 4539 4540 spin_lock(&devices_kset->list_lock); 4541 } 4542 spin_unlock(&devices_kset->list_lock); 4543 } 4544 4545 /* 4546 * Device logging functions 4547 */ 4548 4549 #ifdef CONFIG_PRINTK 4550 static void 4551 set_dev_info(const struct device *dev, struct dev_printk_info *dev_info) 4552 { 4553 const char *subsys; 4554 4555 memset(dev_info, 0, sizeof(*dev_info)); 4556 4557 if (dev->class) 4558 subsys = dev->class->name; 4559 else if (dev->bus) 4560 subsys = dev->bus->name; 4561 else 4562 return; 4563 4564 strscpy(dev_info->subsystem, subsys, sizeof(dev_info->subsystem)); 4565 4566 /* 4567 * Add device identifier DEVICE=: 4568 * b12:8 block dev_t 4569 * c127:3 char dev_t 4570 * n8 netdev ifindex 4571 * +sound:card0 subsystem:devname 4572 */ 4573 if (MAJOR(dev->devt)) { 4574 char c; 4575 4576 if (strcmp(subsys, "block") == 0) 4577 c = 'b'; 4578 else 4579 c = 'c'; 4580 4581 snprintf(dev_info->device, sizeof(dev_info->device), 4582 "%c%u:%u", c, MAJOR(dev->devt), MINOR(dev->devt)); 4583 } else if (strcmp(subsys, "net") == 0) { 4584 struct net_device *net = to_net_dev(dev); 4585 4586 snprintf(dev_info->device, sizeof(dev_info->device), 4587 "n%u", net->ifindex); 4588 } else { 4589 snprintf(dev_info->device, sizeof(dev_info->device), 4590 "+%s:%s", subsys, dev_name(dev)); 4591 } 4592 } 4593 4594 int dev_vprintk_emit(int level, const struct device *dev, 4595 const char *fmt, va_list args) 4596 { 4597 struct dev_printk_info dev_info; 4598 4599 set_dev_info(dev, &dev_info); 4600 4601 return vprintk_emit(0, level, &dev_info, fmt, args); 4602 } 4603 EXPORT_SYMBOL(dev_vprintk_emit); 4604 4605 int dev_printk_emit(int level, const struct device *dev, const char *fmt, ...) 4606 { 4607 va_list args; 4608 int r; 4609 4610 va_start(args, fmt); 4611 4612 r = dev_vprintk_emit(level, dev, fmt, args); 4613 4614 va_end(args); 4615 4616 return r; 4617 } 4618 EXPORT_SYMBOL(dev_printk_emit); 4619 4620 static void __dev_printk(const char *level, const struct device *dev, 4621 struct va_format *vaf) 4622 { 4623 if (dev) 4624 dev_printk_emit(level[1] - '0', dev, "%s %s: %pV", 4625 dev_driver_string(dev), dev_name(dev), vaf); 4626 else 4627 printk("%s(NULL device *): %pV", level, vaf); 4628 } 4629 4630 void _dev_printk(const char *level, const struct device *dev, 4631 const char *fmt, ...) 4632 { 4633 struct va_format vaf; 4634 va_list args; 4635 4636 va_start(args, fmt); 4637 4638 vaf.fmt = fmt; 4639 vaf.va = &args; 4640 4641 __dev_printk(level, dev, &vaf); 4642 4643 va_end(args); 4644 } 4645 EXPORT_SYMBOL(_dev_printk); 4646 4647 #define define_dev_printk_level(func, kern_level) \ 4648 void func(const struct device *dev, const char *fmt, ...) \ 4649 { \ 4650 struct va_format vaf; \ 4651 va_list args; \ 4652 \ 4653 va_start(args, fmt); \ 4654 \ 4655 vaf.fmt = fmt; \ 4656 vaf.va = &args; \ 4657 \ 4658 __dev_printk(kern_level, dev, &vaf); \ 4659 \ 4660 va_end(args); \ 4661 } \ 4662 EXPORT_SYMBOL(func); 4663 4664 define_dev_printk_level(_dev_emerg, KERN_EMERG); 4665 define_dev_printk_level(_dev_alert, KERN_ALERT); 4666 define_dev_printk_level(_dev_crit, KERN_CRIT); 4667 define_dev_printk_level(_dev_err, KERN_ERR); 4668 define_dev_printk_level(_dev_warn, KERN_WARNING); 4669 define_dev_printk_level(_dev_notice, KERN_NOTICE); 4670 define_dev_printk_level(_dev_info, KERN_INFO); 4671 4672 #endif 4673 4674 /** 4675 * dev_err_probe - probe error check and log helper 4676 * @dev: the pointer to the struct device 4677 * @err: error value to test 4678 * @fmt: printf-style format string 4679 * @...: arguments as specified in the format string 4680 * 4681 * This helper implements common pattern present in probe functions for error 4682 * checking: print debug or error message depending if the error value is 4683 * -EPROBE_DEFER and propagate error upwards. 4684 * In case of -EPROBE_DEFER it sets also defer probe reason, which can be 4685 * checked later by reading devices_deferred debugfs attribute. 4686 * It replaces code sequence:: 4687 * 4688 * if (err != -EPROBE_DEFER) 4689 * dev_err(dev, ...); 4690 * else 4691 * dev_dbg(dev, ...); 4692 * return err; 4693 * 4694 * with:: 4695 * 4696 * return dev_err_probe(dev, err, ...); 4697 * 4698 * Note that it is deemed acceptable to use this function for error 4699 * prints during probe even if the @err is known to never be -EPROBE_DEFER. 4700 * The benefit compared to a normal dev_err() is the standardized format 4701 * of the error code and the fact that the error code is returned. 4702 * 4703 * Returns @err. 4704 * 4705 */ 4706 int dev_err_probe(const struct device *dev, int err, const char *fmt, ...) 4707 { 4708 struct va_format vaf; 4709 va_list args; 4710 4711 va_start(args, fmt); 4712 vaf.fmt = fmt; 4713 vaf.va = &args; 4714 4715 if (err != -EPROBE_DEFER) { 4716 dev_err(dev, "error %pe: %pV", ERR_PTR(err), &vaf); 4717 } else { 4718 device_set_deferred_probe_reason(dev, &vaf); 4719 dev_dbg(dev, "error %pe: %pV", ERR_PTR(err), &vaf); 4720 } 4721 4722 va_end(args); 4723 4724 return err; 4725 } 4726 EXPORT_SYMBOL_GPL(dev_err_probe); 4727 4728 static inline bool fwnode_is_primary(struct fwnode_handle *fwnode) 4729 { 4730 return fwnode && !IS_ERR(fwnode->secondary); 4731 } 4732 4733 /** 4734 * set_primary_fwnode - Change the primary firmware node of a given device. 4735 * @dev: Device to handle. 4736 * @fwnode: New primary firmware node of the device. 4737 * 4738 * Set the device's firmware node pointer to @fwnode, but if a secondary 4739 * firmware node of the device is present, preserve it. 4740 * 4741 * Valid fwnode cases are: 4742 * - primary --> secondary --> -ENODEV 4743 * - primary --> NULL 4744 * - secondary --> -ENODEV 4745 * - NULL 4746 */ 4747 void set_primary_fwnode(struct device *dev, struct fwnode_handle *fwnode) 4748 { 4749 struct device *parent = dev->parent; 4750 struct fwnode_handle *fn = dev->fwnode; 4751 4752 if (fwnode) { 4753 if (fwnode_is_primary(fn)) 4754 fn = fn->secondary; 4755 4756 if (fn) { 4757 WARN_ON(fwnode->secondary); 4758 fwnode->secondary = fn; 4759 } 4760 dev->fwnode = fwnode; 4761 } else { 4762 if (fwnode_is_primary(fn)) { 4763 dev->fwnode = fn->secondary; 4764 /* Set fn->secondary = NULL, so fn remains the primary fwnode */ 4765 if (!(parent && fn == parent->fwnode)) 4766 fn->secondary = NULL; 4767 } else { 4768 dev->fwnode = NULL; 4769 } 4770 } 4771 } 4772 EXPORT_SYMBOL_GPL(set_primary_fwnode); 4773 4774 /** 4775 * set_secondary_fwnode - Change the secondary firmware node of a given device. 4776 * @dev: Device to handle. 4777 * @fwnode: New secondary firmware node of the device. 4778 * 4779 * If a primary firmware node of the device is present, set its secondary 4780 * pointer to @fwnode. Otherwise, set the device's firmware node pointer to 4781 * @fwnode. 4782 */ 4783 void set_secondary_fwnode(struct device *dev, struct fwnode_handle *fwnode) 4784 { 4785 if (fwnode) 4786 fwnode->secondary = ERR_PTR(-ENODEV); 4787 4788 if (fwnode_is_primary(dev->fwnode)) 4789 dev->fwnode->secondary = fwnode; 4790 else 4791 dev->fwnode = fwnode; 4792 } 4793 EXPORT_SYMBOL_GPL(set_secondary_fwnode); 4794 4795 /** 4796 * device_set_of_node_from_dev - reuse device-tree node of another device 4797 * @dev: device whose device-tree node is being set 4798 * @dev2: device whose device-tree node is being reused 4799 * 4800 * Takes another reference to the new device-tree node after first dropping 4801 * any reference held to the old node. 4802 */ 4803 void device_set_of_node_from_dev(struct device *dev, const struct device *dev2) 4804 { 4805 of_node_put(dev->of_node); 4806 dev->of_node = of_node_get(dev2->of_node); 4807 dev->of_node_reused = true; 4808 } 4809 EXPORT_SYMBOL_GPL(device_set_of_node_from_dev); 4810 4811 void device_set_node(struct device *dev, struct fwnode_handle *fwnode) 4812 { 4813 dev->fwnode = fwnode; 4814 dev->of_node = to_of_node(fwnode); 4815 } 4816 EXPORT_SYMBOL_GPL(device_set_node); 4817 4818 int device_match_name(struct device *dev, const void *name) 4819 { 4820 return sysfs_streq(dev_name(dev), name); 4821 } 4822 EXPORT_SYMBOL_GPL(device_match_name); 4823 4824 int device_match_of_node(struct device *dev, const void *np) 4825 { 4826 return dev->of_node == np; 4827 } 4828 EXPORT_SYMBOL_GPL(device_match_of_node); 4829 4830 int device_match_fwnode(struct device *dev, const void *fwnode) 4831 { 4832 return dev_fwnode(dev) == fwnode; 4833 } 4834 EXPORT_SYMBOL_GPL(device_match_fwnode); 4835 4836 int device_match_devt(struct device *dev, const void *pdevt) 4837 { 4838 return dev->devt == *(dev_t *)pdevt; 4839 } 4840 EXPORT_SYMBOL_GPL(device_match_devt); 4841 4842 int device_match_acpi_dev(struct device *dev, const void *adev) 4843 { 4844 return ACPI_COMPANION(dev) == adev; 4845 } 4846 EXPORT_SYMBOL(device_match_acpi_dev); 4847 4848 int device_match_acpi_handle(struct device *dev, const void *handle) 4849 { 4850 return ACPI_HANDLE(dev) == handle; 4851 } 4852 EXPORT_SYMBOL(device_match_acpi_handle); 4853 4854 int device_match_any(struct device *dev, const void *unused) 4855 { 4856 return 1; 4857 } 4858 EXPORT_SYMBOL_GPL(device_match_any); 4859