drivers/input/serio/serio.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *  The Serio abstraction module
   4  *
   5  *  Copyright (c) 1999-2004 Vojtech Pavlik
   6  *  Copyright (c) 2004 Dmitry Torokhov
   7  *  Copyright (c) 2003 Daniele Bellucci
   8  */
   9
  10 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  11
  12 #include <linux/stddef.h>
  13 #include <linux/module.h>
  14 #include <linux/serio.h>
  15 #include <linux/errno.h>
  16 #include <linux/sched.h>
  17 #include <linux/slab.h>
  18 #include <linux/workqueue.h>
  19 #include <linux/mutex.h>
  20
  21 MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
  22 MODULE_DESCRIPTION("Serio abstraction core");
  23 MODULE_LICENSE("GPL");
  24
  25 /*
  26  * serio_mutex protects entire serio subsystem and is taken every time
  27  * serio port or driver registered or unregistered.
  28  */
  29 static DEFINE_MUTEX(serio_mutex);
  30
  31 static LIST_HEAD(serio_list);
  32
  33 static void serio_add_port(struct serio *serio);
  34 static int serio_reconnect_port(struct serio *serio);
  35 static void serio_disconnect_port(struct serio *serio);
  36 static void serio_reconnect_subtree(struct serio *serio);
  37 static void serio_attach_driver(struct serio_driver *drv);
  38
  39 static int serio_connect_driver(struct serio *serio, struct serio_driver *drv)
  40 {
  41         guard(mutex)(&serio->drv_mutex);
  42
  43         return drv->connect(serio, drv);
  44 }
  45
  46 static int serio_reconnect_driver(struct serio *serio)
  47 {
  48         guard(mutex)(&serio->drv_mutex);
  49
  50         if (serio->drv && serio->drv->reconnect)
  51                 return serio->drv->reconnect(serio);
  52
  53         return -1;
  54 }
  55
  56 static void serio_disconnect_driver(struct serio *serio)
  57 {
  58         guard(mutex)(&serio->drv_mutex);
  59
  60         if (serio->drv)
  61                 serio->drv->disconnect(serio);
  62 }
  63
  64 static int serio_match_port(const struct serio_device_id *ids, struct serio *serio)
  65 {
  66         while (ids->type || ids->proto) {
  67                 if ((ids->type == SERIO_ANY || ids->type == serio->id.type) &&
  68                     (ids->proto == SERIO_ANY || ids->proto == serio->id.proto) &&
  69                     (ids->extra == SERIO_ANY || ids->extra == serio->id.extra) &&
  70                     (ids->id == SERIO_ANY || ids->id == serio->id.id))
  71                         return 1;
  72                 ids++;
  73         }
  74         return 0;
  75 }
  76
  77 /*
  78  * Basic serio -> driver core mappings
  79  */
  80
  81 static int serio_bind_driver(struct serio *serio, struct serio_driver *drv)
  82 {
  83         int error;
  84
  85         if (serio_match_port(drv->id_table, serio)) {
  86
  87                 serio->dev.driver = &drv->driver;
  88                 if (serio_connect_driver(serio, drv)) {
  89                         serio->dev.driver = NULL;
  90                         return -ENODEV;
  91                 }
  92
  93                 error = device_bind_driver(&serio->dev);
  94                 if (error) {
  95                         dev_warn(&serio->dev,
  96                                  "device_bind_driver() failed for %s (%s) and %s, error: %d\n",
  97                                  serio->phys, serio->name,
  98                                  drv->description, error);
  99                         serio_disconnect_driver(serio);
 100                         serio->dev.driver = NULL;
 101                         return error;
 102                 }
 103         }
 104         return 0;
 105 }
 106
 107 static void serio_find_driver(struct serio *serio)
 108 {
 109         int error;
 110
 111         error = device_attach(&serio->dev);
 112         if (error < 0 && error != -EPROBE_DEFER)
 113                 dev_warn(&serio->dev,
 114                          "device_attach() failed for %s (%s), error: %d\n",
 115                          serio->phys, serio->name, error);
 116 }
 117
 118
 119 /*
 120  * Serio event processing.
 121  */
 122
 123 enum serio_event_type {
 124         SERIO_RESCAN_PORT,
 125         SERIO_RECONNECT_PORT,
 126         SERIO_RECONNECT_SUBTREE,
 127         SERIO_REGISTER_PORT,
 128         SERIO_ATTACH_DRIVER,
 129 };
 130
 131 struct serio_event {
 132         enum serio_event_type type;
 133         void *object;
 134         struct module *owner;
 135         struct list_head node;
 136 };
 137
 138 static DEFINE_SPINLOCK(serio_event_lock);       /* protects serio_event_list */
 139 static LIST_HEAD(serio_event_list);
 140
 141 static struct serio_event *serio_get_event(void)
 142 {
 143         struct serio_event *event = NULL;
 144
 145         guard(spinlock_irqsave)(&serio_event_lock);
 146
 147         if (!list_empty(&serio_event_list)) {
 148                 event = list_first_entry(&serio_event_list,
 149                                          struct serio_event, node);
 150                 list_del_init(&event->node);
 151         }
 152
 153         return event;
 154 }
 155
 156 static void serio_free_event(struct serio_event *event)
 157 {
 158         module_put(event->owner);
 159         kfree(event);
 160 }
 161
 162 static void serio_remove_duplicate_events(void *object,
 163                                           enum serio_event_type type)
 164 {
 165         struct serio_event *e, *next;
 166
 167         guard(spinlock_irqsave)(&serio_event_lock);
 168
 169         list_for_each_entry_safe(e, next, &serio_event_list, node) {
 170                 if (object == e->object) {
 171                         /*
 172                          * If this event is of different type we should not
 173                          * look further - we only suppress duplicate events
 174                          * that were sent back-to-back.
 175                          */
 176                         if (type != e->type)
 177                                 break;
 178
 179                         list_del_init(&e->node);
 180                         serio_free_event(e);
 181                 }
 182         }
 183 }
 184
 185 static void serio_handle_event(struct work_struct *work)
 186 {
 187         struct serio_event *event;
 188
 189         guard(mutex)(&serio_mutex);
 190
 191         while ((event = serio_get_event())) {
 192
 193                 switch (event->type) {
 194
 195                 case SERIO_REGISTER_PORT:
 196                         serio_add_port(event->object);
 197                         break;
 198
 199                 case SERIO_RECONNECT_PORT:
 200                         serio_reconnect_port(event->object);
 201                         break;
 202
 203                 case SERIO_RESCAN_PORT:
 204                         serio_disconnect_port(event->object);
 205                         serio_find_driver(event->object);
 206                         break;
 207
 208                 case SERIO_RECONNECT_SUBTREE:
 209                         serio_reconnect_subtree(event->object);
 210                         break;
 211
 212                 case SERIO_ATTACH_DRIVER:
 213                         serio_attach_driver(event->object);
 214                         break;
 215                 }
 216
 217                 serio_remove_duplicate_events(event->object, event->type);
 218                 serio_free_event(event);
 219         }
 220 }
 221
 222 static DECLARE_WORK(serio_event_work, serio_handle_event);
 223
 224 static int serio_queue_event(void *object, struct module *owner,
 225                              enum serio_event_type event_type)
 226 {
 227         struct serio_event *event;
 228
 229         guard(spinlock_irqsave)(&serio_event_lock);
 230
 231         /*
 232          * Scan event list for the other events for the same serio port,
 233          * starting with the most recent one. If event is the same we
 234          * do not need add new one. If event is of different type we
 235          * need to add this event and should not look further because
 236          * we need to preseve sequence of distinct events.
 237          */
 238         list_for_each_entry_reverse(event, &serio_event_list, node) {
 239                 if (event->object == object) {
 240                         if (event->type == event_type)
 241                                 return 0;
 242                         break;
 243                 }
 244         }
 245
 246         event = kmalloc(sizeof(*event), GFP_ATOMIC);
 247         if (!event) {
 248                 pr_err("Not enough memory to queue event %d\n", event_type);
 249                 return -ENOMEM;
 250         }
 251
 252         if (!try_module_get(owner)) {
 253                 pr_warn("Can't get module reference, dropping event %d\n",
 254                         event_type);
 255                 kfree(event);
 256                 return -EINVAL;
 257         }
 258
 259         event->type = event_type;
 260         event->object = object;
 261         event->owner = owner;
 262
 263         list_add_tail(&event->node, &serio_event_list);
 264         queue_work(system_long_wq, &serio_event_work);
 265
 266         return 0;
 267 }
 268
 269 /*
 270  * Remove all events that have been submitted for a given
 271  * object, be it serio port or driver.
 272  */
 273 static void serio_remove_pending_events(void *object)
 274 {
 275         struct serio_event *event, *next;
 276
 277         guard(spinlock_irqsave)(&serio_event_lock);
 278
 279         list_for_each_entry_safe(event, next, &serio_event_list, node) {
 280                 if (event->object == object) {
 281                         list_del_init(&event->node);
 282                         serio_free_event(event);
 283                 }
 284         }
 285 }
 286
 287 /*
 288  * Locate child serio port (if any) that has not been fully registered yet.
 289  *
 290  * Children are registered by driver's connect() handler so there can't be a
 291  * grandchild pending registration together with a child.
 292  */
 293 static struct serio *serio_get_pending_child(struct serio *parent)
 294 {
 295         struct serio_event *event;
 296         struct serio *serio;
 297
 298         guard(spinlock_irqsave)(&serio_event_lock);
 299
 300         list_for_each_entry(event, &serio_event_list, node) {
 301                 if (event->type == SERIO_REGISTER_PORT) {
 302                         serio = event->object;
 303                         if (serio->parent == parent)
 304                                 return serio;
 305                 }
 306         }
 307
 308         return NULL;
 309 }
 310
 311 /*
 312  * Serio port operations
 313  */
 314
 315 static ssize_t serio_show_description(struct device *dev, struct device_attribute *attr, char *buf)
 316 {
 317         struct serio *serio = to_serio_port(dev);
 318         return sprintf(buf, "%s\n", serio->name);
 319 }
 320
 321 static ssize_t modalias_show(struct device *dev, struct device_attribute *attr, char *buf)
 322 {
 323         struct serio *serio = to_serio_port(dev);
 324
 325         return sprintf(buf, "serio:ty%02Xpr%02Xid%02Xex%02X\n",
 326                         serio->id.type, serio->id.proto, serio->id.id, serio->id.extra);
 327 }
 328
 329 static ssize_t type_show(struct device *dev, struct device_attribute *attr, char *buf)
 330 {
 331         struct serio *serio = to_serio_port(dev);
 332         return sprintf(buf, "%02x\n", serio->id.type);
 333 }
 334
 335 static ssize_t proto_show(struct device *dev, struct device_attribute *attr, char *buf)
 336 {
 337         struct serio *serio = to_serio_port(dev);
 338         return sprintf(buf, "%02x\n", serio->id.proto);
 339 }
 340
 341 static ssize_t id_show(struct device *dev, struct device_attribute *attr, char *buf)
 342 {
 343         struct serio *serio = to_serio_port(dev);
 344         return sprintf(buf, "%02x\n", serio->id.id);
 345 }
 346
 347 static ssize_t extra_show(struct device *dev, struct device_attribute *attr, char *buf)
 348 {
 349         struct serio *serio = to_serio_port(dev);
 350         return sprintf(buf, "%02x\n", serio->id.extra);
 351 }
 352
 353 static ssize_t drvctl_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
 354 {
 355         struct serio *serio = to_serio_port(dev);
 356         struct device_driver *drv;
 357         int error;
 358
 359         scoped_cond_guard(mutex_intr, return -EINTR, &serio_mutex) {
 360                 if (!strncmp(buf, "none", count)) {
 361                         serio_disconnect_port(serio);
 362                 } else if (!strncmp(buf, "reconnect", count)) {
 363                         serio_reconnect_subtree(serio);
 364                 } else if (!strncmp(buf, "rescan", count)) {
 365                         serio_disconnect_port(serio);
 366                         serio_find_driver(serio);
 367                         serio_remove_duplicate_events(serio, SERIO_RESCAN_PORT);
 368                 } else if ((drv = driver_find(buf, &serio_bus)) != NULL) {
 369                         serio_disconnect_port(serio);
 370                         error = serio_bind_driver(serio, to_serio_driver(drv));
 371                         serio_remove_duplicate_events(serio, SERIO_RESCAN_PORT);
 372                         if (error)
 373                                 return error;
 374                 } else {
 375                         return -EINVAL;
 376                 }
 377         }
 378
 379         return count;
 380 }
 381
 382 static ssize_t serio_show_bind_mode(struct device *dev, struct device_attribute *attr, char *buf)
 383 {
 384         struct serio *serio = to_serio_port(dev);
 385         return sprintf(buf, "%s\n", serio->manual_bind ? "manual" : "auto");
 386 }
 387
 388 static ssize_t serio_set_bind_mode(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
 389 {
 390         struct serio *serio = to_serio_port(dev);
 391         int retval;
 392
 393         retval = count;
 394         if (!strncmp(buf, "manual", count)) {
 395                 serio->manual_bind = true;
 396         } else if (!strncmp(buf, "auto", count)) {
 397                 serio->manual_bind = false;
 398         } else {
 399                 retval = -EINVAL;
 400         }
 401
 402         return retval;
 403 }
 404
 405 static ssize_t firmware_id_show(struct device *dev, struct device_attribute *attr, char *buf)
 406 {
 407         struct serio *serio = to_serio_port(dev);
 408
 409         return sprintf(buf, "%s\n", serio->firmware_id);
 410 }
 411
 412 static DEVICE_ATTR_RO(type);
 413 static DEVICE_ATTR_RO(proto);
 414 static DEVICE_ATTR_RO(id);
 415 static DEVICE_ATTR_RO(extra);
 416
 417 static struct attribute *serio_device_id_attrs[] = {
 418         &dev_attr_type.attr,
 419         &dev_attr_proto.attr,
 420         &dev_attr_id.attr,
 421         &dev_attr_extra.attr,
 422         NULL
 423 };
 424
 425 static const struct attribute_group serio_id_attr_group = {
 426         .name   = "id",
 427         .attrs  = serio_device_id_attrs,
 428 };
 429
 430 static DEVICE_ATTR_RO(modalias);
 431 static DEVICE_ATTR_WO(drvctl);
 432 static DEVICE_ATTR(description, S_IRUGO, serio_show_description, NULL);
 433 static DEVICE_ATTR(bind_mode, S_IWUSR | S_IRUGO, serio_show_bind_mode, serio_set_bind_mode);
 434 static DEVICE_ATTR_RO(firmware_id);
 435
 436 static struct attribute *serio_device_attrs[] = {
 437         &dev_attr_modalias.attr,
 438         &dev_attr_description.attr,
 439         &dev_attr_drvctl.attr,
 440         &dev_attr_bind_mode.attr,
 441         &dev_attr_firmware_id.attr,
 442         NULL
 443 };
 444
 445 static const struct attribute_group serio_device_attr_group = {
 446         .attrs  = serio_device_attrs,
 447 };
 448
 449 static const struct attribute_group *serio_device_attr_groups[] = {
 450         &serio_id_attr_group,
 451         &serio_device_attr_group,
 452         NULL
 453 };
 454
 455 static void serio_release_port(struct device *dev)
 456 {
 457         struct serio *serio = to_serio_port(dev);
 458
 459         kfree(serio);
 460         module_put(THIS_MODULE);
 461 }
 462
 463 /*
 464  * Prepare serio port for registration.
 465  */
 466 static void serio_init_port(struct serio *serio)
 467 {
 468         static atomic_t serio_no = ATOMIC_INIT(-1);
 469
 470         __module_get(THIS_MODULE);
 471
 472         INIT_LIST_HEAD(&serio->node);
 473         INIT_LIST_HEAD(&serio->child_node);
 474         INIT_LIST_HEAD(&serio->children);
 475         spin_lock_init(&serio->lock);
 476         mutex_init(&serio->drv_mutex);
 477         device_initialize(&serio->dev);
 478         dev_set_name(&serio->dev, "serio%lu",
 479                      (unsigned long)atomic_inc_return(&serio_no));
 480         serio->dev.bus = &serio_bus;
 481         serio->dev.release = serio_release_port;
 482         serio->dev.groups = serio_device_attr_groups;
 483         if (serio->parent) {
 484                 serio->dev.parent = &serio->parent->dev;
 485                 serio->depth = serio->parent->depth + 1;
 486         } else
 487                 serio->depth = 0;
 488         lockdep_set_subclass(&serio->lock, serio->depth);
 489 }
 490
 491 /*
 492  * Complete serio port registration.
 493  * Driver core will attempt to find appropriate driver for the port.
 494  */
 495 static void serio_add_port(struct serio *serio)
 496 {
 497         struct serio *parent = serio->parent;
 498         int error;
 499
 500         if (parent) {
 501                 guard(serio_pause_rx)(parent);
 502
 503                 list_add_tail(&serio->child_node, &parent->children);
 504         }
 505
 506         list_add_tail(&serio->node, &serio_list);
 507
 508         if (serio->start)
 509                 serio->start(serio);
 510
 511         error = device_add(&serio->dev);
 512         if (error)
 513                 dev_err(&serio->dev,
 514                         "device_add() failed for %s (%s), error: %d\n",
 515                         serio->phys, serio->name, error);
 516 }
 517
 518 /*
 519  * serio_destroy_port() completes unregistration process and removes
 520  * port from the system
 521  */
 522 static void serio_destroy_port(struct serio *serio)
 523 {
 524         struct serio *child;
 525
 526         while ((child = serio_get_pending_child(serio)) != NULL) {
 527                 serio_remove_pending_events(child);
 528                 put_device(&child->dev);
 529         }
 530
 531         if (serio->stop)
 532                 serio->stop(serio);
 533
 534         if (serio->parent) {
 535                 guard(serio_pause_rx)(serio->parent);
 536
 537                 list_del_init(&serio->child_node);
 538                 serio->parent = NULL;
 539         }
 540
 541         if (device_is_registered(&serio->dev))
 542                 device_del(&serio->dev);
 543
 544         list_del_init(&serio->node);
 545         serio_remove_pending_events(serio);
 546         put_device(&serio->dev);
 547 }
 548
 549 /*
 550  * Reconnect serio port (re-initialize attached device).
 551  * If reconnect fails (old device is no longer attached or
 552  * there was no device to begin with) we do full rescan in
 553  * hope of finding a driver for the port.
 554  */
 555 static int serio_reconnect_port(struct serio *serio)
 556 {
 557         int error = serio_reconnect_driver(serio);
 558
 559         if (error) {
 560                 serio_disconnect_port(serio);
 561                 serio_find_driver(serio);
 562         }
 563
 564         return error;
 565 }
 566
 567 /*
 568  * Reconnect serio port and all its children (re-initialize attached
 569  * devices).
 570  */
 571 static void serio_reconnect_subtree(struct serio *root)
 572 {
 573         struct serio *s = root;
 574         int error;
 575
 576         do {
 577                 error = serio_reconnect_port(s);
 578                 if (!error) {
 579                         /*
 580                          * Reconnect was successful, move on to do the
 581                          * first child.
 582                          */
 583                         if (!list_empty(&s->children)) {
 584                                 s = list_first_entry(&s->children,
 585                                                      struct serio, child_node);
 586                                 continue;
 587                         }
 588                 }
 589
 590                 /*
 591                  * Either it was a leaf node or reconnect failed and it
 592                  * became a leaf node. Continue reconnecting starting with
 593                  * the next sibling of the parent node.
 594                  */
 595                 while (s != root) {
 596                         struct serio *parent = s->parent;
 597
 598                         if (!list_is_last(&s->child_node, &parent->children)) {
 599                                 s = list_entry(s->child_node.next,
 600                                                struct serio, child_node);
 601                                 break;
 602                         }
 603
 604                         s = parent;
 605                 }
 606         } while (s != root);
 607 }
 608
 609 /*
 610  * serio_disconnect_port() unbinds a port from its driver. As a side effect
 611  * all children ports are unbound and destroyed.
 612  */
 613 static void serio_disconnect_port(struct serio *serio)
 614 {
 615         struct serio *s = serio;
 616
 617         /*
 618          * Children ports should be disconnected and destroyed
 619          * first; we travel the tree in depth-first order.
 620          */
 621         while (!list_empty(&serio->children)) {
 622
 623                 /* Locate a leaf */
 624                 while (!list_empty(&s->children))
 625                         s = list_first_entry(&s->children,
 626                                              struct serio, child_node);
 627
 628                 /*
 629                  * Prune this leaf node unless it is the one we
 630                  * started with.
 631                  */
 632                 if (s != serio) {
 633                         struct serio *parent = s->parent;
 634
 635                         device_release_driver(&s->dev);
 636                         serio_destroy_port(s);
 637
 638                         s = parent;
 639                 }
 640         }
 641
 642         /*
 643          * OK, no children left, now disconnect this port.
 644          */
 645         device_release_driver(&serio->dev);
 646 }
 647
 648 void serio_rescan(struct serio *serio)
 649 {
 650         serio_queue_event(serio, NULL, SERIO_RESCAN_PORT);
 651 }
 652 EXPORT_SYMBOL(serio_rescan);
 653
 654 void serio_reconnect(struct serio *serio)
 655 {
 656         serio_queue_event(serio, NULL, SERIO_RECONNECT_SUBTREE);
 657 }
 658 EXPORT_SYMBOL(serio_reconnect);
 659
 660 /*
 661  * Submits register request to kseriod for subsequent execution.
 662  * Note that port registration is always asynchronous.
 663  */
 664 void __serio_register_port(struct serio *serio, struct module *owner)
 665 {
 666         serio_init_port(serio);
 667         serio_queue_event(serio, owner, SERIO_REGISTER_PORT);
 668 }
 669 EXPORT_SYMBOL(__serio_register_port);
 670
 671 /*
 672  * Synchronously unregisters serio port.
 673  */
 674 void serio_unregister_port(struct serio *serio)
 675 {
 676         guard(mutex)(&serio_mutex);
 677
 678         serio_disconnect_port(serio);
 679         serio_destroy_port(serio);
 680 }
 681 EXPORT_SYMBOL(serio_unregister_port);
 682
 683 /*
 684  * Safely unregisters children ports if they are present.
 685  */
 686 void serio_unregister_child_port(struct serio *serio)
 687 {
 688         struct serio *s, *next;
 689
 690         guard(mutex)(&serio_mutex);
 691
 692         list_for_each_entry_safe(s, next, &serio->children, child_node) {
 693                 serio_disconnect_port(s);
 694                 serio_destroy_port(s);
 695         }
 696 }
 697 EXPORT_SYMBOL(serio_unregister_child_port);
 698
 699
 700 /*
 701  * Serio driver operations
 702  */
 703
 704 static ssize_t description_show(struct device_driver *drv, char *buf)
 705 {
 706         struct serio_driver *driver = to_serio_driver(drv);
 707         return sprintf(buf, "%s\n", driver->description ? driver->description : "(none)");
 708 }
 709 static DRIVER_ATTR_RO(description);
 710
 711 static ssize_t bind_mode_show(struct device_driver *drv, char *buf)
 712 {
 713         struct serio_driver *serio_drv = to_serio_driver(drv);
 714         return sprintf(buf, "%s\n", serio_drv->manual_bind ? "manual" : "auto");
 715 }
 716
 717 static ssize_t bind_mode_store(struct device_driver *drv, const char *buf, size_t count)
 718 {
 719         struct serio_driver *serio_drv = to_serio_driver(drv);
 720         int retval;
 721
 722         retval = count;
 723         if (!strncmp(buf, "manual", count)) {
 724                 serio_drv->manual_bind = true;
 725         } else if (!strncmp(buf, "auto", count)) {
 726                 serio_drv->manual_bind = false;
 727         } else {
 728                 retval = -EINVAL;
 729         }
 730
 731         return retval;
 732 }
 733 static DRIVER_ATTR_RW(bind_mode);
 734
 735 static struct attribute *serio_driver_attrs[] = {
 736         &driver_attr_description.attr,
 737         &driver_attr_bind_mode.attr,
 738         NULL,
 739 };
 740 ATTRIBUTE_GROUPS(serio_driver);
 741
 742 static int serio_driver_probe(struct device *dev)
 743 {
 744         struct serio *serio = to_serio_port(dev);
 745         struct serio_driver *drv = to_serio_driver(dev->driver);
 746
 747         return serio_connect_driver(serio, drv);
 748 }
 749
 750 static void serio_driver_remove(struct device *dev)
 751 {
 752         struct serio *serio = to_serio_port(dev);
 753
 754         serio_disconnect_driver(serio);
 755 }
 756
 757 static void serio_cleanup(struct serio *serio)
 758 {
 759         guard(mutex)(&serio->drv_mutex);
 760
 761         if (serio->drv && serio->drv->cleanup)
 762                 serio->drv->cleanup(serio);
 763 }
 764
 765 static void serio_shutdown(struct device *dev)
 766 {
 767         struct serio *serio = to_serio_port(dev);
 768
 769         serio_cleanup(serio);
 770 }
 771
 772 static void serio_attach_driver(struct serio_driver *drv)
 773 {
 774         int error;
 775
 776         error = driver_attach(&drv->driver);
 777         if (error)
 778                 pr_warn("driver_attach() failed for %s with error %d\n",
 779                         drv->driver.name, error);
 780 }
 781
 782 int __serio_register_driver(struct serio_driver *drv, struct module *owner, const char *mod_name)
 783 {
 784         bool manual_bind = drv->manual_bind;
 785         int error;
 786
 787         drv->driver.bus = &serio_bus;
 788         drv->driver.owner = owner;
 789         drv->driver.mod_name = mod_name;
 790
 791         /*
 792          * Temporarily disable automatic binding because probing
 793          * takes long time and we are better off doing it in kseriod
 794          */
 795         drv->manual_bind = true;
 796
 797         error = driver_register(&drv->driver);
 798         if (error) {
 799                 pr_err("driver_register() failed for %s, error: %d\n",
 800                         drv->driver.name, error);
 801                 return error;
 802         }
 803
 804         /*
 805          * Restore original bind mode and let kseriod bind the
 806          * driver to free ports
 807          */
 808         if (!manual_bind) {
 809                 drv->manual_bind = false;
 810                 error = serio_queue_event(drv, NULL, SERIO_ATTACH_DRIVER);
 811                 if (error) {
 812                         driver_unregister(&drv->driver);
 813                         return error;
 814                 }
 815         }
 816
 817         return 0;
 818 }
 819 EXPORT_SYMBOL(__serio_register_driver);
 820
 821 void serio_unregister_driver(struct serio_driver *drv)
 822 {
 823         struct serio *serio;
 824
 825         guard(mutex)(&serio_mutex);
 826
 827         drv->manual_bind = true;        /* so serio_find_driver ignores it */
 828         serio_remove_pending_events(drv);
 829
 830 start_over:
 831         list_for_each_entry(serio, &serio_list, node) {
 832                 if (serio->drv == drv) {
 833                         serio_disconnect_port(serio);
 834                         serio_find_driver(serio);
 835                         /* we could've deleted some ports, restart */
 836                         goto start_over;
 837                 }
 838         }
 839
 840         driver_unregister(&drv->driver);
 841 }
 842 EXPORT_SYMBOL(serio_unregister_driver);
 843
 844 static void serio_set_drv(struct serio *serio, struct serio_driver *drv)
 845 {
 846         guard(serio_pause_rx)(serio);
 847
 848         serio->drv = drv;
 849 }
 850
 851 static int serio_bus_match(struct device *dev, const struct device_driver *drv)
 852 {
 853         struct serio *serio = to_serio_port(dev);
 854         const struct serio_driver *serio_drv = to_serio_driver(drv);
 855
 856         if (serio->manual_bind || serio_drv->manual_bind)
 857                 return 0;
 858
 859         return serio_match_port(serio_drv->id_table, serio);
 860 }
 861
 862 #define SERIO_ADD_UEVENT_VAR(fmt, val...)                               \
 863         do {                                                            \
 864                 int err = add_uevent_var(env, fmt, val);                \
 865                 if (err)                                                \
 866                         return err;                                     \
 867         } while (0)
 868
 869 static int serio_uevent(const struct device *dev, struct kobj_uevent_env *env)
 870 {
 871         const struct serio *serio;
 872
 873         if (!dev)
 874                 return -ENODEV;
 875
 876         serio = to_serio_port(dev);
 877
 878         SERIO_ADD_UEVENT_VAR("SERIO_TYPE=%02x", serio->id.type);
 879         SERIO_ADD_UEVENT_VAR("SERIO_PROTO=%02x", serio->id.proto);
 880         SERIO_ADD_UEVENT_VAR("SERIO_ID=%02x", serio->id.id);
 881         SERIO_ADD_UEVENT_VAR("SERIO_EXTRA=%02x", serio->id.extra);
 882
 883         SERIO_ADD_UEVENT_VAR("MODALIAS=serio:ty%02Xpr%02Xid%02Xex%02X",
 884                                 serio->id.type, serio->id.proto, serio->id.id, serio->id.extra);
 885
 886         if (serio->firmware_id[0])
 887                 SERIO_ADD_UEVENT_VAR("SERIO_FIRMWARE_ID=%s",
 888                                      serio->firmware_id);
 889
 890         return 0;
 891 }
 892 #undef SERIO_ADD_UEVENT_VAR
 893
 894 #ifdef CONFIG_PM
 895 static int serio_suspend(struct device *dev)
 896 {
 897         struct serio *serio = to_serio_port(dev);
 898
 899         serio_cleanup(serio);
 900
 901         return 0;
 902 }
 903
 904 static int serio_resume(struct device *dev)
 905 {
 906         struct serio *serio = to_serio_port(dev);
 907         int error = -ENOENT;
 908
 909         scoped_guard(mutex, &serio->drv_mutex) {
 910                 if (serio->drv && serio->drv->fast_reconnect) {
 911                         error = serio->drv->fast_reconnect(serio);
 912                         if (error && error != -ENOENT)
 913                                 dev_warn(dev, "fast reconnect failed with error %d\n",
 914                                          error);
 915                 }
 916         }
 917
 918         if (error) {
 919                 /*
 920                  * Driver reconnect can take a while, so better let
 921                  * kseriod deal with it.
 922                  */
 923                 serio_queue_event(serio, NULL, SERIO_RECONNECT_PORT);
 924         }
 925
 926         return 0;
 927 }
 928
 929 static const struct dev_pm_ops serio_pm_ops = {
 930         .suspend        = serio_suspend,
 931         .resume         = serio_resume,
 932         .poweroff       = serio_suspend,
 933         .restore        = serio_resume,
 934 };
 935 #endif /* CONFIG_PM */
 936
 937 /* called from serio_driver->connect/disconnect methods under serio_mutex */
 938 int serio_open(struct serio *serio, struct serio_driver *drv)
 939 {
 940         serio_set_drv(serio, drv);
 941
 942         if (serio->open && serio->open(serio)) {
 943                 serio_set_drv(serio, NULL);
 944                 return -1;
 945         }
 946         return 0;
 947 }
 948 EXPORT_SYMBOL(serio_open);
 949
 950 /* called from serio_driver->connect/disconnect methods under serio_mutex */
 951 void serio_close(struct serio *serio)
 952 {
 953         if (serio->close)
 954                 serio->close(serio);
 955
 956         serio_set_drv(serio, NULL);
 957 }
 958 EXPORT_SYMBOL(serio_close);
 959
 960 irqreturn_t serio_interrupt(struct serio *serio,
 961                 unsigned char data, unsigned int dfl)
 962 {
 963         guard(spinlock_irqsave)(&serio->lock);
 964
 965         if (likely(serio->drv))
 966                 return serio->drv->interrupt(serio, data, dfl);
 967
 968         if (!dfl && device_is_registered(&serio->dev)) {
 969                 serio_rescan(serio);
 970                 return IRQ_HANDLED;
 971         }
 972
 973         return IRQ_NONE;
 974 }
 975 EXPORT_SYMBOL(serio_interrupt);
 976
 977 const struct bus_type serio_bus = {
 978         .name           = "serio",
 979         .drv_groups     = serio_driver_groups,
 980         .match          = serio_bus_match,
 981         .uevent         = serio_uevent,
 982         .probe          = serio_driver_probe,
 983         .remove         = serio_driver_remove,
 984         .shutdown       = serio_shutdown,
 985 #ifdef CONFIG_PM
 986         .pm             = &serio_pm_ops,
 987 #endif
 988 };
 989 EXPORT_SYMBOL(serio_bus);
 990
 991 static int __init serio_init(void)
 992 {
 993         int error;
 994
 995         error = bus_register(&serio_bus);
 996         if (error) {
 997                 pr_err("Failed to register serio bus, error: %d\n", error);
 998                 return error;
 999         }
1000
1001         return 0;
1002 }
1003
1004 static void __exit serio_exit(void)
1005 {
1006         bus_unregister(&serio_bus);
1007
1008         /*
1009          * There should not be any outstanding events but work may
1010          * still be scheduled so simply cancel it.
1011          */
1012         cancel_work_sync(&serio_event_work);
1013 }
1014
1015 subsys_initcall(serio_init);
1016 module_exit(serio_exit);