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serio.c

/*
 *  The Serio abstraction module
 *
 *  Copyright (c) 1999-2004 Vojtech Pavlik
 *  Copyright (c) 2004 Dmitry Torokhov
 *  Copyright (c) 2003 Daniele Bellucci
 */

/*
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 *
 * Should you need to contact me, the author, you can do so either by
 * e-mail - mail your message to <vojtech@ucw.cz>, or by paper mail:
 * Vojtech Pavlik, Simunkova 1594, Prague 8, 182 00 Czech Republic
 */

#include <linux/stddef.h>
#include <linux/module.h>
#include <linux/serio.h>
#include <linux/errno.h>
#include <linux/wait.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/kthread.h>
#include <linux/mutex.h>
#include <linux/freezer.h>

MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
MODULE_DESCRIPTION("Serio abstraction core");
MODULE_LICENSE("GPL");

EXPORT_SYMBOL(serio_interrupt);
EXPORT_SYMBOL(__serio_register_port);
EXPORT_SYMBOL(serio_unregister_port);
EXPORT_SYMBOL(serio_unregister_child_port);
EXPORT_SYMBOL(__serio_register_driver);
EXPORT_SYMBOL(serio_unregister_driver);
EXPORT_SYMBOL(serio_open);
EXPORT_SYMBOL(serio_close);
EXPORT_SYMBOL(serio_rescan);
EXPORT_SYMBOL(serio_reconnect);

/*
 * serio_mutex protects entire serio subsystem and is taken every time
 * serio port or driver registrered or unregistered.
 */
static DEFINE_MUTEX(serio_mutex);

static LIST_HEAD(serio_list);

static struct bus_type serio_bus;

static void serio_add_port(struct serio *serio);
static void serio_reconnect_port(struct serio *serio);
static void serio_disconnect_port(struct serio *serio);
static void serio_attach_driver(struct serio_driver *drv);

static int serio_connect_driver(struct serio *serio, struct serio_driver *drv)
{
      int retval;

      mutex_lock(&serio->drv_mutex);
      retval = drv->connect(serio, drv);
      mutex_unlock(&serio->drv_mutex);

      return retval;
}

static int serio_reconnect_driver(struct serio *serio)
{
      int retval = -1;

      mutex_lock(&serio->drv_mutex);
      if (serio->drv && serio->drv->reconnect)
            retval = serio->drv->reconnect(serio);
      mutex_unlock(&serio->drv_mutex);

      return retval;
}

static void serio_disconnect_driver(struct serio *serio)
{
      mutex_lock(&serio->drv_mutex);
      if (serio->drv)
            serio->drv->disconnect(serio);
      mutex_unlock(&serio->drv_mutex);
}

static int serio_match_port(const struct serio_device_id *ids, struct serio *serio)
{
      while (ids->type || ids->proto) {
            if ((ids->type == SERIO_ANY || ids->type == serio->id.type) &&
                (ids->proto == SERIO_ANY || ids->proto == serio->id.proto) &&
                (ids->extra == SERIO_ANY || ids->extra == serio->id.extra) &&
                (ids->id == SERIO_ANY || ids->id == serio->id.id))
                  return 1;
            ids++;
      }
      return 0;
}

/*
 * Basic serio -> driver core mappings
 */

static int serio_bind_driver(struct serio *serio, struct serio_driver *drv)
{
      int error;

      if (serio_match_port(drv->id_table, serio)) {

            serio->dev.driver = &drv->driver;
            if (serio_connect_driver(serio, drv)) {
                  serio->dev.driver = NULL;
                  return -ENODEV;
            }

            error = device_bind_driver(&serio->dev);
            if (error) {
                  printk(KERN_WARNING
                        "serio: device_bind_driver() failed "
                        "for %s (%s) and %s, error: %d\n",
                        serio->phys, serio->name,
                        drv->description, error);
                  serio_disconnect_driver(serio);
                  serio->dev.driver = NULL;
                  return error;
            }
      }
      return 0;
}

static void serio_find_driver(struct serio *serio)
{
      int error;

      error = device_attach(&serio->dev);
      if (error < 0)
            printk(KERN_WARNING
                  "serio: device_attach() failed for %s (%s), error: %d\n",
                  serio->phys, serio->name, error);
}


/*
 * Serio event processing.
 */

enum serio_event_type {
      SERIO_RESCAN_PORT,
      SERIO_RECONNECT_PORT,
      SERIO_REGISTER_PORT,
      SERIO_ATTACH_DRIVER,
};

struct serio_event {
      enum serio_event_type type;
      void *object;
      struct module *owner;
      struct list_head node;
};

static DEFINE_SPINLOCK(serio_event_lock); /* protects serio_event_list */
static LIST_HEAD(serio_event_list);
static DECLARE_WAIT_QUEUE_HEAD(serio_wait);
static struct task_struct *serio_task;

static int serio_queue_event(void *object, struct module *owner,
                       enum serio_event_type event_type)
{
      unsigned long flags;
      struct serio_event *event;
      int retval = 0;

      spin_lock_irqsave(&serio_event_lock, flags);

      /*
       * Scan event list for the other events for the same serio port,
       * starting with the most recent one. If event is the same we
       * do not need add new one. If event is of different type we
       * need to add this event and should not look further because
       * we need to preseve sequence of distinct events.
       */
      list_for_each_entry_reverse(event, &serio_event_list, node) {
            if (event->object == object) {
                  if (event->type == event_type)
                        goto out;
                  break;
            }
      }

      event = kmalloc(sizeof(struct serio_event), GFP_ATOMIC);
      if (!event) {
            printk(KERN_ERR
                  "serio: Not enough memory to queue event %d\n",
                  event_type);
            retval = -ENOMEM;
            goto out;
      }

      if (!try_module_get(owner)) {
            printk(KERN_WARNING
                  "serio: Can't get module reference, dropping event %d\n",
                  event_type);
            kfree(event);
            retval = -EINVAL;
            goto out;
      }

      event->type = event_type;
      event->object = object;
      event->owner = owner;

      list_add_tail(&event->node, &serio_event_list);
      wake_up(&serio_wait);

out:
      spin_unlock_irqrestore(&serio_event_lock, flags);
      return retval;
}

static void serio_free_event(struct serio_event *event)
{
      module_put(event->owner);
      kfree(event);
}

static void serio_remove_duplicate_events(struct serio_event *event)
{
      struct list_head *node, *next;
      struct serio_event *e;
      unsigned long flags;

      spin_lock_irqsave(&serio_event_lock, flags);

      list_for_each_safe(node, next, &serio_event_list) {
            e = list_entry(node, struct serio_event, node);
            if (event->object == e->object) {
                  /*
                   * If this event is of different type we should not
                   * look further - we only suppress duplicate events
                   * that were sent back-to-back.
                   */
                  if (event->type != e->type)
                        break;

                  list_del_init(node);
                  serio_free_event(e);
            }
      }

      spin_unlock_irqrestore(&serio_event_lock, flags);
}


static struct serio_event *serio_get_event(void)
{
      struct serio_event *event;
      struct list_head *node;
      unsigned long flags;

      spin_lock_irqsave(&serio_event_lock, flags);

      if (list_empty(&serio_event_list)) {
            spin_unlock_irqrestore(&serio_event_lock, flags);
            return NULL;
      }

      node = serio_event_list.next;
      event = list_entry(node, struct serio_event, node);
      list_del_init(node);

      spin_unlock_irqrestore(&serio_event_lock, flags);

      return event;
}

static void serio_handle_event(void)
{
      struct serio_event *event;

      mutex_lock(&serio_mutex);

      /*
       * Note that we handle only one event here to give swsusp
       * a chance to freeze kseriod thread. Serio events should
       * be pretty rare so we are not concerned about taking
       * performance hit.
       */
      if ((event = serio_get_event())) {

            switch (event->type) {
                  case SERIO_REGISTER_PORT:
                        serio_add_port(event->object);
                        break;

                  case SERIO_RECONNECT_PORT:
                        serio_reconnect_port(event->object);
                        break;

                  case SERIO_RESCAN_PORT:
                        serio_disconnect_port(event->object);
                        serio_find_driver(event->object);
                        break;

                  case SERIO_ATTACH_DRIVER:
                        serio_attach_driver(event->object);
                        break;

                  default:
                        break;
            }

            serio_remove_duplicate_events(event);
            serio_free_event(event);
      }

      mutex_unlock(&serio_mutex);
}

/*
 * Remove all events that have been submitted for a given serio port.
 */
static void serio_remove_pending_events(struct serio *serio)
{
      struct list_head *node, *next;
      struct serio_event *event;
      unsigned long flags;

      spin_lock_irqsave(&serio_event_lock, flags);

      list_for_each_safe(node, next, &serio_event_list) {
            event = list_entry(node, struct serio_event, node);
            if (event->object == serio) {
                  list_del_init(node);
                  serio_free_event(event);
            }
      }

      spin_unlock_irqrestore(&serio_event_lock, flags);
}

/*
 * Destroy child serio port (if any) that has not been fully registered yet.
 *
 * Note that we rely on the fact that port can have only one child and therefore
 * only one child registration request can be pending. Additionally, children
 * are registered by driver's connect() handler so there can't be a grandchild
 * pending registration together with a child.
 */
static struct serio *serio_get_pending_child(struct serio *parent)
{
      struct serio_event *event;
      struct serio *serio, *child = NULL;
      unsigned long flags;

      spin_lock_irqsave(&serio_event_lock, flags);

      list_for_each_entry(event, &serio_event_list, node) {
            if (event->type == SERIO_REGISTER_PORT) {
                  serio = event->object;
                  if (serio->parent == parent) {
                        child = serio;
                        break;
                  }
            }
      }

      spin_unlock_irqrestore(&serio_event_lock, flags);
      return child;
}

static int serio_thread(void *nothing)
{
      set_freezable();
      do {
            serio_handle_event();
            wait_event_freezable(serio_wait,
                  kthread_should_stop() || !list_empty(&serio_event_list));
      } while (!kthread_should_stop());

      printk(KERN_DEBUG "serio: kseriod exiting\n");
      return 0;
}


/*
 * Serio port operations
 */

static ssize_t serio_show_description(struct device *dev, struct device_attribute *attr, char *buf)
{
      struct serio *serio = to_serio_port(dev);
      return sprintf(buf, "%s\n", serio->name);
}

static ssize_t serio_show_modalias(struct device *dev, struct device_attribute *attr, char *buf)
{
      struct serio *serio = to_serio_port(dev);

      return sprintf(buf, "serio:ty%02Xpr%02Xid%02Xex%02X\n",
                  serio->id.type, serio->id.proto, serio->id.id, serio->id.extra);
}

static ssize_t serio_show_id_type(struct device *dev, struct device_attribute *attr, char *buf)
{
      struct serio *serio = to_serio_port(dev);
      return sprintf(buf, "%02x\n", serio->id.type);
}

static ssize_t serio_show_id_proto(struct device *dev, struct device_attribute *attr, char *buf)
{
      struct serio *serio = to_serio_port(dev);
      return sprintf(buf, "%02x\n", serio->id.proto);
}

static ssize_t serio_show_id_id(struct device *dev, struct device_attribute *attr, char *buf)
{
      struct serio *serio = to_serio_port(dev);
      return sprintf(buf, "%02x\n", serio->id.id);
}

static ssize_t serio_show_id_extra(struct device *dev, struct device_attribute *attr, char *buf)
{
      struct serio *serio = to_serio_port(dev);
      return sprintf(buf, "%02x\n", serio->id.extra);
}

static DEVICE_ATTR(type, S_IRUGO, serio_show_id_type, NULL);
static DEVICE_ATTR(proto, S_IRUGO, serio_show_id_proto, NULL);
static DEVICE_ATTR(id, S_IRUGO, serio_show_id_id, NULL);
static DEVICE_ATTR(extra, S_IRUGO, serio_show_id_extra, NULL);

static struct attribute *serio_device_id_attrs[] = {
      &dev_attr_type.attr,
      &dev_attr_proto.attr,
      &dev_attr_id.attr,
      &dev_attr_extra.attr,
      NULL
};

static struct attribute_group serio_id_attr_group = {
      .name = "id",
      .attrs      = serio_device_id_attrs,
};

static ssize_t serio_rebind_driver(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
{
      struct serio *serio = to_serio_port(dev);
      struct device_driver *drv;
      int error;

      error = mutex_lock_interruptible(&serio_mutex);
      if (error)
            return error;

      if (!strncmp(buf, "none", count)) {
            serio_disconnect_port(serio);
      } else if (!strncmp(buf, "reconnect", count)) {
            serio_reconnect_port(serio);
      } else if (!strncmp(buf, "rescan", count)) {
            serio_disconnect_port(serio);
            serio_find_driver(serio);
      } else if ((drv = driver_find(buf, &serio_bus)) != NULL) {
            serio_disconnect_port(serio);
            error = serio_bind_driver(serio, to_serio_driver(drv));
            put_driver(drv);
      } else {
            error = -EINVAL;
      }

      mutex_unlock(&serio_mutex);

      return error ? error : count;
}

static ssize_t serio_show_bind_mode(struct device *dev, struct device_attribute *attr, char *buf)
{
      struct serio *serio = to_serio_port(dev);
      return sprintf(buf, "%s\n", serio->manual_bind ? "manual" : "auto");
}

static ssize_t serio_set_bind_mode(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
{
      struct serio *serio = to_serio_port(dev);
      int retval;

      retval = count;
      if (!strncmp(buf, "manual", count)) {
            serio->manual_bind = 1;
      } else if (!strncmp(buf, "auto", count)) {
            serio->manual_bind = 0;
      } else {
            retval = -EINVAL;
      }

      return retval;
}

static struct device_attribute serio_device_attrs[] = {
      __ATTR(description, S_IRUGO, serio_show_description, NULL),
      __ATTR(modalias, S_IRUGO, serio_show_modalias, NULL),
      __ATTR(drvctl, S_IWUSR, NULL, serio_rebind_driver),
      __ATTR(bind_mode, S_IWUSR | S_IRUGO, serio_show_bind_mode, serio_set_bind_mode),
      __ATTR_NULL
};


static void serio_release_port(struct device *dev)
{
      struct serio *serio = to_serio_port(dev);

      kfree(serio);
      module_put(THIS_MODULE);
}

/*
 * Prepare serio port for registration.
 */
static void serio_init_port(struct serio *serio)
{
      static atomic_t serio_no = ATOMIC_INIT(0);

      __module_get(THIS_MODULE);

      INIT_LIST_HEAD(&serio->node);
      spin_lock_init(&serio->lock);
      mutex_init(&serio->drv_mutex);
      device_initialize(&serio->dev);
      snprintf(serio->dev.bus_id, sizeof(serio->dev.bus_id),
             "serio%ld", (long)atomic_inc_return(&serio_no) - 1);
      serio->dev.bus = &serio_bus;
      serio->dev.release = serio_release_port;
      if (serio->parent) {
            serio->dev.parent = &serio->parent->dev;
            serio->depth = serio->parent->depth + 1;
      } else
            serio->depth = 0;
      lockdep_set_subclass(&serio->lock, serio->depth);
}

/*
 * Complete serio port registration.
 * Driver core will attempt to find appropriate driver for the port.
 */
static void serio_add_port(struct serio *serio)
{
      int error;

      if (serio->parent) {
            serio_pause_rx(serio->parent);
            serio->parent->child = serio;
            serio_continue_rx(serio->parent);
      }

      list_add_tail(&serio->node, &serio_list);
      if (serio->start)
            serio->start(serio);
      error = device_add(&serio->dev);
      if (error)
            printk(KERN_ERR
                  "serio: device_add() failed for %s (%s), error: %d\n",
                  serio->phys, serio->name, error);
      else {
            serio->registered = 1;
            error = sysfs_create_group(&serio->dev.kobj, &serio_id_attr_group);
            if (error)
                  printk(KERN_ERR
                        "serio: sysfs_create_group() failed for %s (%s), error: %d\n",
                        serio->phys, serio->name, error);
      }
}

/*
 * serio_destroy_port() completes deregistration process and removes
 * port from the system
 */
static void serio_destroy_port(struct serio *serio)
{
      struct serio *child;

      child = serio_get_pending_child(serio);
      if (child) {
            serio_remove_pending_events(child);
            put_device(&child->dev);
      }

      if (serio->stop)
            serio->stop(serio);

      if (serio->parent) {
            serio_pause_rx(serio->parent);
            serio->parent->child = NULL;
            serio_continue_rx(serio->parent);
            serio->parent = NULL;
      }

      if (serio->registered) {
            sysfs_remove_group(&serio->dev.kobj, &serio_id_attr_group);
            device_del(&serio->dev);
            serio->registered = 0;
      }

      list_del_init(&serio->node);
      serio_remove_pending_events(serio);
      put_device(&serio->dev);
}

/*
 * Reconnect serio port and all its children (re-initialize attached devices)
 */
static void serio_reconnect_port(struct serio *serio)
{
      do {
            if (serio_reconnect_driver(serio)) {
                  serio_disconnect_port(serio);
                  serio_find_driver(serio);
                  /* Ok, old children are now gone, we are done */
                  break;
            }
            serio = serio->child;
      } while (serio);
}

/*
 * serio_disconnect_port() unbinds a port from its driver. As a side effect
 * all child ports are unbound and destroyed.
 */
static void serio_disconnect_port(struct serio *serio)
{
      struct serio *s, *parent;

      if (serio->child) {
            /*
             * Children ports should be disconnected and destroyed
             * first, staring with the leaf one, since we don't want
             * to do recursion
             */
            for (s = serio; s->child; s = s->child)
                  /* empty */;

            do {
                  parent = s->parent;

                  device_release_driver(&s->dev);
                  serio_destroy_port(s);
            } while ((s = parent) != serio);
      }

      /*
       * Ok, no children left, now disconnect this port
       */
      device_release_driver(&serio->dev);
}

void serio_rescan(struct serio *serio)
{
      serio_queue_event(serio, NULL, SERIO_RESCAN_PORT);
}

void serio_reconnect(struct serio *serio)
{
      serio_queue_event(serio, NULL, SERIO_RECONNECT_PORT);
}

/*
 * Submits register request to kseriod for subsequent execution.
 * Note that port registration is always asynchronous.
 */
void __serio_register_port(struct serio *serio, struct module *owner)
{
      serio_init_port(serio);
      serio_queue_event(serio, owner, SERIO_REGISTER_PORT);
}

/*
 * Synchronously unregisters serio port.
 */
void serio_unregister_port(struct serio *serio)
{
      mutex_lock(&serio_mutex);
      serio_disconnect_port(serio);
      serio_destroy_port(serio);
      mutex_unlock(&serio_mutex);
}

/*
 * Safely unregisters child port if one is present.
 */
void serio_unregister_child_port(struct serio *serio)
{
      mutex_lock(&serio_mutex);
      if (serio->child) {
            serio_disconnect_port(serio->child);
            serio_destroy_port(serio->child);
      }
      mutex_unlock(&serio_mutex);
}


/*
 * Serio driver operations
 */

static ssize_t serio_driver_show_description(struct device_driver *drv, char *buf)
{
      struct serio_driver *driver = to_serio_driver(drv);
      return sprintf(buf, "%s\n", driver->description ? driver->description : "(none)");
}

static ssize_t serio_driver_show_bind_mode(struct device_driver *drv, char *buf)
{
      struct serio_driver *serio_drv = to_serio_driver(drv);
      return sprintf(buf, "%s\n", serio_drv->manual_bind ? "manual" : "auto");
}

static ssize_t serio_driver_set_bind_mode(struct device_driver *drv, const char *buf, size_t count)
{
      struct serio_driver *serio_drv = to_serio_driver(drv);
      int retval;

      retval = count;
      if (!strncmp(buf, "manual", count)) {
            serio_drv->manual_bind = 1;
      } else if (!strncmp(buf, "auto", count)) {
            serio_drv->manual_bind = 0;
      } else {
            retval = -EINVAL;
      }

      return retval;
}


static struct driver_attribute serio_driver_attrs[] = {
      __ATTR(description, S_IRUGO, serio_driver_show_description, NULL),
      __ATTR(bind_mode, S_IWUSR | S_IRUGO,
            serio_driver_show_bind_mode, serio_driver_set_bind_mode),
      __ATTR_NULL
};

static int serio_driver_probe(struct device *dev)
{
      struct serio *serio = to_serio_port(dev);
      struct serio_driver *drv = to_serio_driver(dev->driver);

      return serio_connect_driver(serio, drv);
}

static int serio_driver_remove(struct device *dev)
{
      struct serio *serio = to_serio_port(dev);

      serio_disconnect_driver(serio);
      return 0;
}

static void serio_cleanup(struct serio *serio)
{
      mutex_lock(&serio->drv_mutex);
      if (serio->drv && serio->drv->cleanup)
            serio->drv->cleanup(serio);
      mutex_unlock(&serio->drv_mutex);
}

static void serio_shutdown(struct device *dev)
{
      struct serio *serio = to_serio_port(dev);

      serio_cleanup(serio);
}

static void serio_attach_driver(struct serio_driver *drv)
{
      int error;

      error = driver_attach(&drv->driver);
      if (error)
            printk(KERN_WARNING
                  "serio: driver_attach() failed for %s with error %d\n",
                  drv->driver.name, error);
}

int __serio_register_driver(struct serio_driver *drv, struct module *owner, const char *mod_name)
{
      int manual_bind = drv->manual_bind;
      int error;

      drv->driver.bus = &serio_bus;
      drv->driver.owner = owner;
      drv->driver.mod_name = mod_name;

      /*
       * Temporarily disable automatic binding because probing
       * takes long time and we are better off doing it in kseriod
       */
      drv->manual_bind = 1;

      error = driver_register(&drv->driver);
      if (error) {
            printk(KERN_ERR
                  "serio: driver_register() failed for %s, error: %d\n",
                  drv->driver.name, error);
            return error;
      }

      /*
       * Restore original bind mode and let kseriod bind the
       * driver to free ports
       */
      if (!manual_bind) {
            drv->manual_bind = 0;
            error = serio_queue_event(drv, NULL, SERIO_ATTACH_DRIVER);
            if (error) {
                  driver_unregister(&drv->driver);
                  return error;
            }
      }

      return 0;
}

void serio_unregister_driver(struct serio_driver *drv)
{
      struct serio *serio;

      mutex_lock(&serio_mutex);
      drv->manual_bind = 1;   /* so serio_find_driver ignores it */

start_over:
      list_for_each_entry(serio, &serio_list, node) {
            if (serio->drv == drv) {
                  serio_disconnect_port(serio);
                  serio_find_driver(serio);
                  /* we could've deleted some ports, restart */
                  goto start_over;
            }
      }

      driver_unregister(&drv->driver);
      mutex_unlock(&serio_mutex);
}

static void serio_set_drv(struct serio *serio, struct serio_driver *drv)
{
      serio_pause_rx(serio);
      serio->drv = drv;
      serio_continue_rx(serio);
}

static int serio_bus_match(struct device *dev, struct device_driver *drv)
{
      struct serio *serio = to_serio_port(dev);
      struct serio_driver *serio_drv = to_serio_driver(drv);

      if (serio->manual_bind || serio_drv->manual_bind)
            return 0;

      return serio_match_port(serio_drv->id_table, serio);
}

#ifdef CONFIG_HOTPLUG

#define SERIO_ADD_UEVENT_VAR(fmt, val...)                   \
      do {                                            \
            int err = add_uevent_var(env, fmt, val);        \
            if (err)                                  \
                  return err;                         \
      } while (0)

static int serio_uevent(struct device *dev, struct kobj_uevent_env *env)
{
      struct serio *serio;

      if (!dev)
            return -ENODEV;

      serio = to_serio_port(dev);

      SERIO_ADD_UEVENT_VAR("SERIO_TYPE=%02x", serio->id.type);
      SERIO_ADD_UEVENT_VAR("SERIO_PROTO=%02x", serio->id.proto);
      SERIO_ADD_UEVENT_VAR("SERIO_ID=%02x", serio->id.id);
      SERIO_ADD_UEVENT_VAR("SERIO_EXTRA=%02x", serio->id.extra);
      SERIO_ADD_UEVENT_VAR("MODALIAS=serio:ty%02Xpr%02Xid%02Xex%02X",
                        serio->id.type, serio->id.proto, serio->id.id, serio->id.extra);

      return 0;
}
#undef SERIO_ADD_UEVENT_VAR

#else

static int serio_uevent(struct device *dev, struct kobj_uevent_env *env)
{
      return -ENODEV;
}

#endif /* CONFIG_HOTPLUG */

#ifdef CONFIG_PM
static int serio_suspend(struct device *dev, pm_message_t state)
{
      if (dev->power.power_state.event != state.event) {
            if (state.event == PM_EVENT_SUSPEND)
                  serio_cleanup(to_serio_port(dev));

            dev->power.power_state = state;
      }

      return 0;
}

static int serio_resume(struct device *dev)
{
      struct serio *serio = to_serio_port(dev);

      if (dev->power.power_state.event != PM_EVENT_ON &&
          serio_reconnect_driver(serio)) {
            /*
             * Driver re-probing can take a while, so better let kseriod
             * deal with it.
             */
            serio_rescan(serio);
      }

      dev->power.power_state = PMSG_ON;

      return 0;
}
#endif /* CONFIG_PM */

/* called from serio_driver->connect/disconnect methods under serio_mutex */
int serio_open(struct serio *serio, struct serio_driver *drv)
{
      serio_set_drv(serio, drv);

      if (serio->open && serio->open(serio)) {
            serio_set_drv(serio, NULL);
            return -1;
      }
      return 0;
}

/* called from serio_driver->connect/disconnect methods under serio_mutex */
void serio_close(struct serio *serio)
{
      if (serio->close)
            serio->close(serio);

      serio_set_drv(serio, NULL);
}

irqreturn_t serio_interrupt(struct serio *serio,
            unsigned char data, unsigned int dfl)
{
      unsigned long flags;
      irqreturn_t ret = IRQ_NONE;

      spin_lock_irqsave(&serio->lock, flags);

        if (likely(serio->drv)) {
                ret = serio->drv->interrupt(serio, data, dfl);
      } else if (!dfl && serio->registered) {
            serio_rescan(serio);
            ret = IRQ_HANDLED;
      }

      spin_unlock_irqrestore(&serio->lock, flags);

      return ret;
}

static struct bus_type serio_bus = {
      .name       = "serio",
      .dev_attrs  = serio_device_attrs,
      .drv_attrs  = serio_driver_attrs,
      .match            = serio_bus_match,
      .uevent           = serio_uevent,
      .probe            = serio_driver_probe,
      .remove           = serio_driver_remove,
      .shutdown   = serio_shutdown,
#ifdef CONFIG_PM
      .suspend    = serio_suspend,
      .resume           = serio_resume,
#endif
};

static int __init serio_init(void)
{
      int error;

      error = bus_register(&serio_bus);
      if (error) {
            printk(KERN_ERR "serio: failed to register serio bus, error: %d\n", error);
            return error;
      }

      serio_task = kthread_run(serio_thread, NULL, "kseriod");
      if (IS_ERR(serio_task)) {
            bus_unregister(&serio_bus);
            error = PTR_ERR(serio_task);
            printk(KERN_ERR "serio: Failed to start kseriod, error: %d\n", error);
            return error;
      }

      return 0;
}

static void __exit serio_exit(void)
{
      bus_unregister(&serio_bus);
      kthread_stop(serio_task);
}

subsys_initcall(serio_init);
module_exit(serio_exit);

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