drivers/input/gameport/gameport.c - fp2-dev/kernel/msm - Gitiles

 /*
  * Generic gameport layer
  *
  * Copyright (c) 1999-2002 Vojtech Pavlik
  * Copyright (c) 2005 Dmitry Torokhov
  */

 /*
  * This program is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 as published by
  * the Free Software Foundation.
  */

 #include <linux/stddef.h>
 #include <linux/module.h>
 #include <linux/ioport.h>
 #include <linux/init.h>
 #include <linux/gameport.h>
 #include <linux/wait.h>
 #include <linux/sched.h>
 #include <linux/slab.h>
 #include <linux/delay.h>
 #include <linux/kthread.h>
 #include <linux/sched.h>	/* HZ */

 /*#include <asm/io.h>*/

 MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
 MODULE_DESCRIPTION("Generic gameport layer");
 MODULE_LICENSE("GPL");

 EXPORT_SYMBOL(__gameport_register_port);
 EXPORT_SYMBOL(gameport_unregister_port);
 EXPORT_SYMBOL(__gameport_register_driver);
 EXPORT_SYMBOL(gameport_unregister_driver);
 EXPORT_SYMBOL(gameport_open);
 EXPORT_SYMBOL(gameport_close);
 EXPORT_SYMBOL(gameport_rescan);
 EXPORT_SYMBOL(gameport_cooked_read);
 EXPORT_SYMBOL(gameport_set_name);
 EXPORT_SYMBOL(gameport_set_phys);
 EXPORT_SYMBOL(gameport_start_polling);
 EXPORT_SYMBOL(gameport_stop_polling);

 /*
  * gameport_sem protects entire gameport subsystem and is taken
  * every time gameport port or driver registrered or unregistered.
  */
 static DECLARE_MUTEX(gameport_sem);

 static LIST_HEAD(gameport_list);

 static struct bus_type gameport_bus = {
 	.name =	"gameport",
 };

 static void gameport_add_port(struct gameport *gameport);
 static void gameport_destroy_port(struct gameport *gameport);
 static void gameport_reconnect_port(struct gameport *gameport);
 static void gameport_disconnect_port(struct gameport *gameport);

 #if defined(__i386__)

 #include <asm/i8253.h>

 #define DELTA(x,y)      ((y)-(x)+((y)<(x)?1193182/HZ:0))
 #define GET_TIME(x)     do { x = get_time_pit(); } while (0)

 static unsigned int get_time_pit(void)
 {
 	unsigned long flags;
 	unsigned int count;

 	spin_lock_irqsave(&i8253_lock, flags);
 	outb_p(0x00, 0x43);
 	count = inb_p(0x40);
 	count |= inb_p(0x40) << 8;
 	spin_unlock_irqrestore(&i8253_lock, flags);

 	return count;
 }

 #endif


 /*
  * gameport_measure_speed() measures the gameport i/o speed.
  */

 static int gameport_measure_speed(struct gameport *gameport)
 {
 #if defined(__i386__)

 	unsigned int i, t, t1, t2, t3, tx;
 	unsigned long flags;

 	if (gameport_open(gameport, NULL, GAMEPORT_MODE_RAW))
 		return 0;

 	tx = 1 << 30;

 	for(i = 0; i < 50; i++) {
 		local_irq_save(flags);
 		GET_TIME(t1);
 		for (t = 0; t < 50; t++) gameport_read(gameport);
 		GET_TIME(t2);
 		GET_TIME(t3);
 		local_irq_restore(flags);
 		udelay(i * 10);
 		if ((t = DELTA(t2,t1) - DELTA(t3,t2)) < tx) tx = t;
 	}

 	gameport_close(gameport);
 	return 59659 / (tx < 1 ? 1 : tx);

 #elif defined (__x86_64__)

 	unsigned int i, t;
 	unsigned long tx, t1, t2, flags;

 	if (gameport_open(gameport, NULL, GAMEPORT_MODE_RAW))
 		return 0;

 	tx = 1 << 30;

 	for(i = 0; i < 50; i++) {
 		local_irq_save(flags);
 		rdtscl(t1);
 		for (t = 0; t < 50; t++) gameport_read(gameport);
 		rdtscl(t2);
 		local_irq_restore(flags);
 		udelay(i * 10);
 		if (t2 - t1 < tx) tx = t2 - t1;
 	}

 	gameport_close(gameport);
 	return (cpu_data[raw_smp_processor_id()].loops_per_jiffy * (unsigned long)HZ / (1000 / 50)) / (tx < 1 ? 1 : tx);

 #else

 	unsigned int j, t = 0;

 	if (gameport_open(gameport, NULL, GAMEPORT_MODE_RAW))
 		return 0;

 	j = jiffies; while (j == jiffies);
 	j = jiffies; while (j == jiffies) { t++; gameport_read(gameport); }

 	gameport_close(gameport);
 	return t * HZ / 1000;

 #endif
 }

 void gameport_start_polling(struct gameport *gameport)
 {
 	spin_lock(&gameport->timer_lock);

 	if (!gameport->poll_cnt++) {
 		BUG_ON(!gameport->poll_handler);
 		BUG_ON(!gameport->poll_interval);
 		mod_timer(&gameport->poll_timer, jiffies + msecs_to_jiffies(gameport->poll_interval));
 	}

 	spin_unlock(&gameport->timer_lock);
 }

 void gameport_stop_polling(struct gameport *gameport)
 {
 	spin_lock(&gameport->timer_lock);

 	if (!--gameport->poll_cnt)
 		del_timer(&gameport->poll_timer);

 	spin_unlock(&gameport->timer_lock);
 }

 static void gameport_run_poll_handler(unsigned long d)
 {
 	struct gameport *gameport = (struct gameport *)d;

 	gameport->poll_handler(gameport);
 	if (gameport->poll_cnt)
 		mod_timer(&gameport->poll_timer, jiffies + msecs_to_jiffies(gameport->poll_interval));
 }

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

 static void gameport_bind_driver(struct gameport *gameport, struct gameport_driver *drv)
 {
 	down_write(&gameport_bus.subsys.rwsem);

 	gameport->dev.driver = &drv->driver;
 	if (drv->connect(gameport, drv)) {
 		gameport->dev.driver = NULL;
 		goto out;
 	}
 	device_bind_driver(&gameport->dev);
 out:
 	up_write(&gameport_bus.subsys.rwsem);
 }

 static void gameport_release_driver(struct gameport *gameport)
 {
 	down_write(&gameport_bus.subsys.rwsem);
 	device_release_driver(&gameport->dev);
 	up_write(&gameport_bus.subsys.rwsem);
 }

 static void gameport_find_driver(struct gameport *gameport)
 {
 	down_write(&gameport_bus.subsys.rwsem);
 	device_attach(&gameport->dev);
 	up_write(&gameport_bus.subsys.rwsem);
 }


 /*
  * Gameport event processing.
  */

 enum gameport_event_type {
 	GAMEPORT_RESCAN,
 	GAMEPORT_RECONNECT,
 	GAMEPORT_REGISTER_PORT,
 	GAMEPORT_REGISTER_DRIVER,
 };

 struct gameport_event {
 	enum gameport_event_type type;
 	void *object;
 	struct module *owner;
 	struct list_head node;
 };

 static DEFINE_SPINLOCK(gameport_event_lock);	/* protects gameport_event_list */
 static LIST_HEAD(gameport_event_list);
 static DECLARE_WAIT_QUEUE_HEAD(gameport_wait);
 static struct task_struct *gameport_task;

 static void gameport_queue_event(void *object, struct module *owner,
 			      enum gameport_event_type event_type)
 {
 	unsigned long flags;
 	struct gameport_event *event;

 	spin_lock_irqsave(&gameport_event_lock, flags);

 	/*
 	 * Scan event list for the other events for the same gameport 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, &gameport_event_list, node) {
 		if (event->object == object) {
 			if (event->type == event_type)
 				goto out;
 			break;
 		}
 	}

 	if ((event = kmalloc(sizeof(struct gameport_event), GFP_ATOMIC))) {
 		if (!try_module_get(owner)) {
 			printk(KERN_WARNING "gameport: Can't get module reference, dropping event %d\n", event_type);
 			goto out;
 		}

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

 		list_add_tail(&event->node, &gameport_event_list);
 		wake_up(&gameport_wait);
 	} else {
 		printk(KERN_ERR "gameport: Not enough memory to queue event %d\n", event_type);
 	}
 out:
 	spin_unlock_irqrestore(&gameport_event_lock, flags);
 }

 static void gameport_free_event(struct gameport_event *event)
 {
 	module_put(event->owner);
 	kfree(event);
 }

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

 	spin_lock_irqsave(&gameport_event_lock, flags);

 	list_for_each_safe(node, next, &gameport_event_list) {
 		e = list_entry(node, struct gameport_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);
 			gameport_free_event(e);
 		}
 	}

 	spin_unlock_irqrestore(&gameport_event_lock, flags);
 }


 static struct gameport_event *gameport_get_event(void)
 {
 	struct gameport_event *event;
 	struct list_head *node;
 	unsigned long flags;

 	spin_lock_irqsave(&gameport_event_lock, flags);

 	if (list_empty(&gameport_event_list)) {
 		spin_unlock_irqrestore(&gameport_event_lock, flags);
 		return NULL;
 	}

 	node = gameport_event_list.next;
 	event = list_entry(node, struct gameport_event, node);
 	list_del_init(node);

 	spin_unlock_irqrestore(&gameport_event_lock, flags);

 	return event;
 }

 static void gameport_handle_event(void)
 {
 	struct gameport_event *event;
 	struct gameport_driver *gameport_drv;

 	down(&gameport_sem);

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

 		switch (event->type) {
 			case GAMEPORT_REGISTER_PORT:
 				gameport_add_port(event->object);
 				break;

 			case GAMEPORT_RECONNECT:
 				gameport_reconnect_port(event->object);
 				break;

 			case GAMEPORT_RESCAN:
 				gameport_disconnect_port(event->object);
 				gameport_find_driver(event->object);
 				break;

 			case GAMEPORT_REGISTER_DRIVER:
 				gameport_drv = event->object;
 				driver_register(&gameport_drv->driver);
 				break;

 			default:
 				break;
 		}

 		gameport_remove_duplicate_events(event);
 		gameport_free_event(event);
 	}

 	up(&gameport_sem);
 }

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

 	spin_lock_irqsave(&gameport_event_lock, flags);

 	list_for_each_safe(node, next, &gameport_event_list) {
 		event = list_entry(node, struct gameport_event, node);
 		if (event->object == gameport) {
 			list_del_init(node);
 			gameport_free_event(event);
 		}
 	}

 	spin_unlock_irqrestore(&gameport_event_lock, flags);
 }

 /*
  * Destroy child gameport 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 gameport *gameport_get_pending_child(struct gameport *parent)
 {
 	struct gameport_event *event;
 	struct gameport *gameport, *child = NULL;
 	unsigned long flags;

 	spin_lock_irqsave(&gameport_event_lock, flags);

 	list_for_each_entry(event, &gameport_event_list, node) {
 		if (event->type == GAMEPORT_REGISTER_PORT) {
 			gameport = event->object;
 			if (gameport->parent == parent) {
 				child = gameport;
 				break;
 			}
 		}
 	}

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

 static int gameport_thread(void *nothing)
 {
 	do {
 		gameport_handle_event();
 		wait_event_interruptible(gameport_wait,
 			kthread_should_stop() || !list_empty(&gameport_event_list));
 		try_to_freeze();
 	} while (!kthread_should_stop());

 	printk(KERN_DEBUG "gameport: kgameportd exiting\n");
 	return 0;
 }


 /*
  * Gameport port operations
  */

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

 static ssize_t gameport_rebind_driver(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
 {
 	struct gameport *gameport = to_gameport_port(dev);
 	struct device_driver *drv;
 	int retval;

 	retval = down_interruptible(&gameport_sem);
 	if (retval)
 		return retval;

 	retval = count;
 	if (!strncmp(buf, "none", count)) {
 		gameport_disconnect_port(gameport);
 	} else if (!strncmp(buf, "reconnect", count)) {
 		gameport_reconnect_port(gameport);
 	} else if (!strncmp(buf, "rescan", count)) {
 		gameport_disconnect_port(gameport);
 		gameport_find_driver(gameport);
 	} else if ((drv = driver_find(buf, &gameport_bus)) != NULL) {
 		gameport_disconnect_port(gameport);
 		gameport_bind_driver(gameport, to_gameport_driver(drv));
 		put_driver(drv);
 	} else {
 		retval = -EINVAL;
 	}

 	up(&gameport_sem);

 	return retval;
 }

 static struct device_attribute gameport_device_attrs[] = {
 	__ATTR(description, S_IRUGO, gameport_show_description, NULL),
 	__ATTR(drvctl, S_IWUSR, NULL, gameport_rebind_driver),
 	__ATTR_NULL
 };

 static void gameport_release_port(struct device *dev)
 {
 	struct gameport *gameport = to_gameport_port(dev);

 	kfree(gameport);
 	module_put(THIS_MODULE);
 }

 void gameport_set_phys(struct gameport *gameport, const char *fmt, ...)
 {
 	va_list args;

 	va_start(args, fmt);
 	vsnprintf(gameport->phys, sizeof(gameport->phys), fmt, args);
 	va_end(args);
 }

 /*
  * Prepare gameport port for registration.
  */
 static void gameport_init_port(struct gameport *gameport)
 {
 	static atomic_t gameport_no = ATOMIC_INIT(0);

 	__module_get(THIS_MODULE);

 	init_MUTEX(&gameport->drv_sem);
 	device_initialize(&gameport->dev);
 	snprintf(gameport->dev.bus_id, sizeof(gameport->dev.bus_id),
 		 "gameport%lu", (unsigned long)atomic_inc_return(&gameport_no) - 1);
 	gameport->dev.bus = &gameport_bus;
 	gameport->dev.release = gameport_release_port;
 	if (gameport->parent)
 		gameport->dev.parent = &gameport->parent->dev;

 	spin_lock_init(&gameport->timer_lock);
 	init_timer(&gameport->poll_timer);
 	gameport->poll_timer.function = gameport_run_poll_handler;
 	gameport->poll_timer.data = (unsigned long)gameport;
 }

 /*
  * Complete gameport port registration.
  * Driver core will attempt to find appropriate driver for the port.
  */
 static void gameport_add_port(struct gameport *gameport)
 {
 	if (gameport->parent)
 		gameport->parent->child = gameport;

 	gameport->speed = gameport_measure_speed(gameport);

 	list_add_tail(&gameport->node, &gameport_list);

 	if (gameport->io)
 		printk(KERN_INFO "gameport: %s is %s, io %#x, speed %dkHz\n",
 			gameport->name, gameport->phys, gameport->io, gameport->speed);
 	else
 		printk(KERN_INFO "gameport: %s is %s, speed %dkHz\n",
 			gameport->name, gameport->phys, gameport->speed);

 	device_add(&gameport->dev);
 	gameport->registered = 1;
 }

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

 	child = gameport_get_pending_child(gameport);
 	if (child) {
 		gameport_remove_pending_events(child);
 		put_device(&child->dev);
 	}

 	if (gameport->parent) {
 		gameport->parent->child = NULL;
 		gameport->parent = NULL;
 	}

 	if (gameport->registered) {
 		device_del(&gameport->dev);
 		list_del_init(&gameport->node);
 		gameport->registered = 0;
 	}

 	gameport_remove_pending_events(gameport);
 	put_device(&gameport->dev);
 }

 /*
  * Reconnect gameport port and all its children (re-initialize attached devices)
  */
 static void gameport_reconnect_port(struct gameport *gameport)
 {
 	do {
 		if (!gameport->drv || !gameport->drv->reconnect || gameport->drv->reconnect(gameport)) {
 			gameport_disconnect_port(gameport);
 			gameport_find_driver(gameport);
 			/* Ok, old children are now gone, we are done */
 			break;
 		}
 		gameport = gameport->child;
 	} while (gameport);
 }

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

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

 		do {
 			parent = s->parent;

 			gameport_release_driver(s);
 			gameport_destroy_port(s);
 		} while ((s = parent) != gameport);
 	}

 	/*
 	 * Ok, no children left, now disconnect this port
 	 */
 	gameport_release_driver(gameport);
 }

 void gameport_rescan(struct gameport *gameport)
 {
 	gameport_queue_event(gameport, NULL, GAMEPORT_RESCAN);
 }

 void gameport_reconnect(struct gameport *gameport)
 {
 	gameport_queue_event(gameport, NULL, GAMEPORT_RECONNECT);
 }

 /*
  * Submits register request to kgameportd for subsequent execution.
  * Note that port registration is always asynchronous.
  */
 void __gameport_register_port(struct gameport *gameport, struct module *owner)
 {
 	gameport_init_port(gameport);
 	gameport_queue_event(gameport, owner, GAMEPORT_REGISTER_PORT);
 }

 /*
  * Synchronously unregisters gameport port.
  */
 void gameport_unregister_port(struct gameport *gameport)
 {
 	down(&gameport_sem);
 	gameport_disconnect_port(gameport);
 	gameport_destroy_port(gameport);
 	up(&gameport_sem);
 }


 /*
  * Gameport driver operations
  */

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

 static struct driver_attribute gameport_driver_attrs[] = {
 	__ATTR(description, S_IRUGO, gameport_driver_show_description, NULL),
 	__ATTR_NULL
 };

 static int gameport_driver_probe(struct device *dev)
 {
 	struct gameport *gameport = to_gameport_port(dev);
 	struct gameport_driver *drv = to_gameport_driver(dev->driver);

 	drv->connect(gameport, drv);
 	return gameport->drv ? 0 : -ENODEV;
 }

 static int gameport_driver_remove(struct device *dev)
 {
 	struct gameport *gameport = to_gameport_port(dev);
 	struct gameport_driver *drv = to_gameport_driver(dev->driver);

 	drv->disconnect(gameport);
 	return 0;
 }

 void __gameport_register_driver(struct gameport_driver *drv, struct module *owner)
 {
 	drv->driver.bus = &gameport_bus;
 	drv->driver.probe = gameport_driver_probe;
 	drv->driver.remove = gameport_driver_remove;
 	gameport_queue_event(drv, owner, GAMEPORT_REGISTER_DRIVER);
 }

 void gameport_unregister_driver(struct gameport_driver *drv)
 {
 	struct gameport *gameport;

 	down(&gameport_sem);
 	drv->ignore = 1;	/* so gameport_find_driver ignores it */

 start_over:
 	list_for_each_entry(gameport, &gameport_list, node) {
 		if (gameport->drv == drv) {
 			gameport_disconnect_port(gameport);
 			gameport_find_driver(gameport);
 			/* we could've deleted some ports, restart */
 			goto start_over;
 		}
 	}

 	driver_unregister(&drv->driver);
 	up(&gameport_sem);
 }

 static int gameport_bus_match(struct device *dev, struct device_driver *drv)
 {
 	struct gameport_driver *gameport_drv = to_gameport_driver(drv);

 	return !gameport_drv->ignore;
 }

 static void gameport_set_drv(struct gameport *gameport, struct gameport_driver *drv)
 {
 	down(&gameport->drv_sem);
 	gameport->drv = drv;
 	up(&gameport->drv_sem);
 }

 int gameport_open(struct gameport *gameport, struct gameport_driver *drv, int mode)
 {

 	if (gameport->open) {
 		if (gameport->open(gameport, mode)) {
 			return -1;
 		}
 	} else {
 		if (mode != GAMEPORT_MODE_RAW)
 			return -1;
 	}

 	gameport_set_drv(gameport, drv);
 	return 0;
 }

 void gameport_close(struct gameport *gameport)
 {
 	del_timer_sync(&gameport->poll_timer);
 	gameport->poll_handler = NULL;
 	gameport->poll_interval = 0;
 	gameport_set_drv(gameport, NULL);
 	if (gameport->close)
 		gameport->close(gameport);
 }

 static int __init gameport_init(void)
 {
 	gameport_task = kthread_run(gameport_thread, NULL, "kgameportd");
 	if (IS_ERR(gameport_task)) {
 		printk(KERN_ERR "gameport: Failed to start kgameportd\n");
 		return PTR_ERR(gameport_task);
 	}

 	gameport_bus.dev_attrs = gameport_device_attrs;
 	gameport_bus.drv_attrs = gameport_driver_attrs;
 	gameport_bus.match = gameport_bus_match;
 	bus_register(&gameport_bus);

 	return 0;
 }

 static void __exit gameport_exit(void)
 {
 	bus_unregister(&gameport_bus);
 	kthread_stop(gameport_task);
 }

 module_init(gameport_init);
 module_exit(gameport_exit);
	/*
	* Generic gameport layer
	*
	* Copyright (c) 1999-2002 Vojtech Pavlik
	* Copyright (c) 2005 Dmitry Torokhov
	*/

	/*
	* This program is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 as published by
	* the Free Software Foundation.
	*/

	#include <linux/stddef.h>
	#include <linux/module.h>
	#include <linux/ioport.h>
	#include <linux/init.h>
	#include <linux/gameport.h>
	#include <linux/wait.h>
	#include <linux/sched.h>
	#include <linux/slab.h>
	#include <linux/delay.h>
	#include <linux/kthread.h>
	#include <linux/sched.h> /* HZ */

	/#include <asm/io.h>/

	MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
	MODULE_DESCRIPTION("Generic gameport layer");
	MODULE_LICENSE("GPL");

	EXPORT_SYMBOL(__gameport_register_port);
	EXPORT_SYMBOL(gameport_unregister_port);
	EXPORT_SYMBOL(__gameport_register_driver);
	EXPORT_SYMBOL(gameport_unregister_driver);
	EXPORT_SYMBOL(gameport_open);
	EXPORT_SYMBOL(gameport_close);
	EXPORT_SYMBOL(gameport_rescan);
	EXPORT_SYMBOL(gameport_cooked_read);
	EXPORT_SYMBOL(gameport_set_name);
	EXPORT_SYMBOL(gameport_set_phys);
	EXPORT_SYMBOL(gameport_start_polling);
	EXPORT_SYMBOL(gameport_stop_polling);

	/*
	* gameport_sem protects entire gameport subsystem and is taken
	* every time gameport port or driver registrered or unregistered.
	*/
	static DECLARE_MUTEX(gameport_sem);

	static LIST_HEAD(gameport_list);

	static struct bus_type gameport_bus = {
	.name = "gameport",
	};

	static void gameport_add_port(struct gameport *gameport);
	static void gameport_destroy_port(struct gameport *gameport);
	static void gameport_reconnect_port(struct gameport *gameport);
	static void gameport_disconnect_port(struct gameport *gameport);

	#if defined(__i386__)

	#include <asm/i8253.h>

	#define DELTA(x,y) ((y)-(x)+((y)<(x)?1193182/HZ:0))
	#define GET_TIME(x) do { x = get_time_pit(); } while (0)

	static unsigned int get_time_pit(void)
	{
	unsigned long flags;
	unsigned int count;

	spin_lock_irqsave(&i8253_lock, flags);
	outb_p(0x00, 0x43);
	count = inb_p(0x40);
	count \|= inb_p(0x40) << 8;
	spin_unlock_irqrestore(&i8253_lock, flags);

	return count;
	}

	#endif



	/*
	* gameport_measure_speed() measures the gameport i/o speed.
	*/

	static int gameport_measure_speed(struct gameport *gameport)
	{
	#if defined(__i386__)

	unsigned int i, t, t1, t2, t3, tx;
	unsigned long flags;

	if (gameport_open(gameport, NULL, GAMEPORT_MODE_RAW))
	return 0;

	tx = 1 << 30;

	for(i = 0; i < 50; i++) {
	local_irq_save(flags);
	GET_TIME(t1);
	for (t = 0; t < 50; t++) gameport_read(gameport);
	GET_TIME(t2);
	GET_TIME(t3);
	local_irq_restore(flags);
	udelay(i * 10);
	if ((t = DELTA(t2,t1) - DELTA(t3,t2)) < tx) tx = t;
	}

	gameport_close(gameport);
	return 59659 / (tx < 1 ? 1 : tx);

	#elif defined (__x86_64__)

	unsigned int i, t;
	unsigned long tx, t1, t2, flags;

	if (gameport_open(gameport, NULL, GAMEPORT_MODE_RAW))
	return 0;

	tx = 1 << 30;

	for(i = 0; i < 50; i++) {
	local_irq_save(flags);
	rdtscl(t1);
	for (t = 0; t < 50; t++) gameport_read(gameport);
	rdtscl(t2);
	local_irq_restore(flags);
	udelay(i * 10);
	if (t2 - t1 < tx) tx = t2 - t1;
	}

	gameport_close(gameport);
	return (cpu_data[raw_smp_processor_id()].loops_per_jiffy * (unsigned long)HZ / (1000 / 50)) / (tx < 1 ? 1 : tx);

	#else

	unsigned int j, t = 0;

	if (gameport_open(gameport, NULL, GAMEPORT_MODE_RAW))
	return 0;

	j = jiffies; while (j == jiffies);
	j = jiffies; while (j == jiffies) { t++; gameport_read(gameport); }

	gameport_close(gameport);
	return t * HZ / 1000;

	#endif
	}

	void gameport_start_polling(struct gameport *gameport)
	{
	spin_lock(&gameport->timer_lock);

	if (!gameport->poll_cnt++) {
	BUG_ON(!gameport->poll_handler);
	BUG_ON(!gameport->poll_interval);
	mod_timer(&gameport->poll_timer, jiffies + msecs_to_jiffies(gameport->poll_interval));
	}

	spin_unlock(&gameport->timer_lock);
	}

	void gameport_stop_polling(struct gameport *gameport)
	{
	spin_lock(&gameport->timer_lock);

	if (!--gameport->poll_cnt)
	del_timer(&gameport->poll_timer);

	spin_unlock(&gameport->timer_lock);
	}

	static void gameport_run_poll_handler(unsigned long d)
	{
	struct gameport gameport = (struct gameport )d;

	gameport->poll_handler(gameport);
	if (gameport->poll_cnt)
	mod_timer(&gameport->poll_timer, jiffies + msecs_to_jiffies(gameport->poll_interval));
	}

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

	static void gameport_bind_driver(struct gameport gameport, struct gameport_driver drv)
	{
	down_write(&gameport_bus.subsys.rwsem);

	gameport->dev.driver = &drv->driver;
	if (drv->connect(gameport, drv)) {
	gameport->dev.driver = NULL;
	goto out;
	}
	device_bind_driver(&gameport->dev);
	out:
	up_write(&gameport_bus.subsys.rwsem);
	}

	static void gameport_release_driver(struct gameport *gameport)
	{
	down_write(&gameport_bus.subsys.rwsem);
	device_release_driver(&gameport->dev);
	up_write(&gameport_bus.subsys.rwsem);
	}

	static void gameport_find_driver(struct gameport *gameport)
	{
	down_write(&gameport_bus.subsys.rwsem);
	device_attach(&gameport->dev);
	up_write(&gameport_bus.subsys.rwsem);
	}


	/*
	* Gameport event processing.
	*/

	enum gameport_event_type {
	GAMEPORT_RESCAN,
	GAMEPORT_RECONNECT,
	GAMEPORT_REGISTER_PORT,
	GAMEPORT_REGISTER_DRIVER,
	};

	struct gameport_event {
	enum gameport_event_type type;
	void *object;
	struct module *owner;
	struct list_head node;
	};

	static DEFINE_SPINLOCK(gameport_event_lock); /* protects gameport_event_list */
	static LIST_HEAD(gameport_event_list);
	static DECLARE_WAIT_QUEUE_HEAD(gameport_wait);
	static struct task_struct *gameport_task;

	static void gameport_queue_event(void object, struct module owner,
	enum gameport_event_type event_type)
	{
	unsigned long flags;
	struct gameport_event *event;

	spin_lock_irqsave(&gameport_event_lock, flags);

	/*
	* Scan event list for the other events for the same gameport 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, &gameport_event_list, node) {
	if (event->object == object) {
	if (event->type == event_type)
	goto out;
	break;
	}
	}

	if ((event = kmalloc(sizeof(struct gameport_event), GFP_ATOMIC))) {
	if (!try_module_get(owner)) {
	printk(KERN_WARNING "gameport: Can't get module reference, dropping event %d\n", event_type);
	goto out;
	}

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

	list_add_tail(&event->node, &gameport_event_list);
	wake_up(&gameport_wait);
	} else {
	printk(KERN_ERR "gameport: Not enough memory to queue event %d\n", event_type);
	}
	out:
	spin_unlock_irqrestore(&gameport_event_lock, flags);
	}

	static void gameport_free_event(struct gameport_event *event)
	{
	module_put(event->owner);
	kfree(event);
	}

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

	spin_lock_irqsave(&gameport_event_lock, flags);

	list_for_each_safe(node, next, &gameport_event_list) {
	e = list_entry(node, struct gameport_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);
	gameport_free_event(e);
	}
	}

	spin_unlock_irqrestore(&gameport_event_lock, flags);
	}


	static struct gameport_event *gameport_get_event(void)
	{
	struct gameport_event *event;
	struct list_head *node;
	unsigned long flags;

	spin_lock_irqsave(&gameport_event_lock, flags);

	if (list_empty(&gameport_event_list)) {
	spin_unlock_irqrestore(&gameport_event_lock, flags);
	return NULL;
	}

	node = gameport_event_list.next;
	event = list_entry(node, struct gameport_event, node);
	list_del_init(node);

	spin_unlock_irqrestore(&gameport_event_lock, flags);

	return event;
	}

	static void gameport_handle_event(void)
	{
	struct gameport_event *event;
	struct gameport_driver *gameport_drv;

	down(&gameport_sem);

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

	switch (event->type) {
	case GAMEPORT_REGISTER_PORT:
	gameport_add_port(event->object);
	break;

	case GAMEPORT_RECONNECT:
	gameport_reconnect_port(event->object);
	break;

	case GAMEPORT_RESCAN:
	gameport_disconnect_port(event->object);
	gameport_find_driver(event->object);
	break;

	case GAMEPORT_REGISTER_DRIVER:
	gameport_drv = event->object;
	driver_register(&gameport_drv->driver);
	break;

	default:
	break;
	}

	gameport_remove_duplicate_events(event);
	gameport_free_event(event);
	}

	up(&gameport_sem);
	}

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

	spin_lock_irqsave(&gameport_event_lock, flags);

	list_for_each_safe(node, next, &gameport_event_list) {
	event = list_entry(node, struct gameport_event, node);
	if (event->object == gameport) {
	list_del_init(node);
	gameport_free_event(event);
	}
	}

	spin_unlock_irqrestore(&gameport_event_lock, flags);
	}

	/*
	* Destroy child gameport 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 gameport gameport_get_pending_child(struct gameport parent)
	{
	struct gameport_event *event;
	struct gameport gameport, child = NULL;
	unsigned long flags;

	spin_lock_irqsave(&gameport_event_lock, flags);

	list_for_each_entry(event, &gameport_event_list, node) {
	if (event->type == GAMEPORT_REGISTER_PORT) {
	gameport = event->object;
	if (gameport->parent == parent) {
	child = gameport;
	break;
	}
	}
	}

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

	static int gameport_thread(void *nothing)
	{
	do {
	gameport_handle_event();
	wait_event_interruptible(gameport_wait,
	kthread_should_stop() \|\| !list_empty(&gameport_event_list));
	try_to_freeze();
	} while (!kthread_should_stop());

	printk(KERN_DEBUG "gameport: kgameportd exiting\n");
	return 0;
	}


	/*
	* Gameport port operations
	*/

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

	static ssize_t gameport_rebind_driver(struct device dev, struct device_attribute attr, const char *buf, size_t count)
	{
	struct gameport *gameport = to_gameport_port(dev);
	struct device_driver *drv;
	int retval;

	retval = down_interruptible(&gameport_sem);
	if (retval)
	return retval;

	retval = count;
	if (!strncmp(buf, "none", count)) {
	gameport_disconnect_port(gameport);
	} else if (!strncmp(buf, "reconnect", count)) {
	gameport_reconnect_port(gameport);
	} else if (!strncmp(buf, "rescan", count)) {
	gameport_disconnect_port(gameport);
	gameport_find_driver(gameport);
	} else if ((drv = driver_find(buf, &gameport_bus)) != NULL) {
	gameport_disconnect_port(gameport);
	gameport_bind_driver(gameport, to_gameport_driver(drv));
	put_driver(drv);
	} else {
	retval = -EINVAL;
	}

	up(&gameport_sem);

	return retval;
	}

	static struct device_attribute gameport_device_attrs[] = {
	__ATTR(description, S_IRUGO, gameport_show_description, NULL),
	__ATTR(drvctl, S_IWUSR, NULL, gameport_rebind_driver),
	__ATTR_NULL
	};

	static void gameport_release_port(struct device *dev)
	{
	struct gameport *gameport = to_gameport_port(dev);

	kfree(gameport);
	module_put(THIS_MODULE);
	}

	void gameport_set_phys(struct gameport gameport, const char fmt, ...)
	{
	va_list args;

	va_start(args, fmt);
	vsnprintf(gameport->phys, sizeof(gameport->phys), fmt, args);
	va_end(args);
	}

	/*
	* Prepare gameport port for registration.
	*/
	static void gameport_init_port(struct gameport *gameport)
	{
	static atomic_t gameport_no = ATOMIC_INIT(0);

	__module_get(THIS_MODULE);

	init_MUTEX(&gameport->drv_sem);
	device_initialize(&gameport->dev);
	snprintf(gameport->dev.bus_id, sizeof(gameport->dev.bus_id),
	"gameport%lu", (unsigned long)atomic_inc_return(&gameport_no) - 1);
	gameport->dev.bus = &gameport_bus;
	gameport->dev.release = gameport_release_port;
	if (gameport->parent)
	gameport->dev.parent = &gameport->parent->dev;

	spin_lock_init(&gameport->timer_lock);
	init_timer(&gameport->poll_timer);
	gameport->poll_timer.function = gameport_run_poll_handler;
	gameport->poll_timer.data = (unsigned long)gameport;
	}

	/*
	* Complete gameport port registration.
	* Driver core will attempt to find appropriate driver for the port.
	*/
	static void gameport_add_port(struct gameport *gameport)
	{
	if (gameport->parent)
	gameport->parent->child = gameport;

	gameport->speed = gameport_measure_speed(gameport);

	list_add_tail(&gameport->node, &gameport_list);

	if (gameport->io)
	printk(KERN_INFO "gameport: %s is %s, io %#x, speed %dkHz\n",
	gameport->name, gameport->phys, gameport->io, gameport->speed);
	else
	printk(KERN_INFO "gameport: %s is %s, speed %dkHz\n",
	gameport->name, gameport->phys, gameport->speed);

	device_add(&gameport->dev);
	gameport->registered = 1;
	}

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

	child = gameport_get_pending_child(gameport);
	if (child) {
	gameport_remove_pending_events(child);
	put_device(&child->dev);
	}

	if (gameport->parent) {
	gameport->parent->child = NULL;
	gameport->parent = NULL;
	}

	if (gameport->registered) {
	device_del(&gameport->dev);
	list_del_init(&gameport->node);
	gameport->registered = 0;
	}

	gameport_remove_pending_events(gameport);
	put_device(&gameport->dev);
	}

	/*
	* Reconnect gameport port and all its children (re-initialize attached devices)
	*/
	static void gameport_reconnect_port(struct gameport *gameport)
	{
	do {
	if (!gameport->drv \|\| !gameport->drv->reconnect \|\| gameport->drv->reconnect(gameport)) {
	gameport_disconnect_port(gameport);
	gameport_find_driver(gameport);
	/* Ok, old children are now gone, we are done */
	break;
	}
	gameport = gameport->child;
	} while (gameport);
	}

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

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

	do {
	parent = s->parent;

	gameport_release_driver(s);
	gameport_destroy_port(s);
	} while ((s = parent) != gameport);
	}

	/*
	* Ok, no children left, now disconnect this port
	*/
	gameport_release_driver(gameport);
	}

	void gameport_rescan(struct gameport *gameport)
	{
	gameport_queue_event(gameport, NULL, GAMEPORT_RESCAN);
	}

	void gameport_reconnect(struct gameport *gameport)
	{
	gameport_queue_event(gameport, NULL, GAMEPORT_RECONNECT);
	}

	/*
	* Submits register request to kgameportd for subsequent execution.
	* Note that port registration is always asynchronous.
	*/
	void __gameport_register_port(struct gameport gameport, struct module owner)
	{
	gameport_init_port(gameport);
	gameport_queue_event(gameport, owner, GAMEPORT_REGISTER_PORT);
	}

	/*
	* Synchronously unregisters gameport port.
	*/
	void gameport_unregister_port(struct gameport *gameport)
	{
	down(&gameport_sem);
	gameport_disconnect_port(gameport);
	gameport_destroy_port(gameport);
	up(&gameport_sem);
	}


	/*
	* Gameport driver operations
	*/

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

	static struct driver_attribute gameport_driver_attrs[] = {
	__ATTR(description, S_IRUGO, gameport_driver_show_description, NULL),
	__ATTR_NULL
	};

	static int gameport_driver_probe(struct device *dev)
	{
	struct gameport *gameport = to_gameport_port(dev);
	struct gameport_driver *drv = to_gameport_driver(dev->driver);

	drv->connect(gameport, drv);
	return gameport->drv ? 0 : -ENODEV;
	}

	static int gameport_driver_remove(struct device *dev)
	{
	struct gameport *gameport = to_gameport_port(dev);
	struct gameport_driver *drv = to_gameport_driver(dev->driver);

	drv->disconnect(gameport);
	return 0;
	}

	void __gameport_register_driver(struct gameport_driver drv, struct module owner)
	{
	drv->driver.bus = &gameport_bus;
	drv->driver.probe = gameport_driver_probe;
	drv->driver.remove = gameport_driver_remove;
	gameport_queue_event(drv, owner, GAMEPORT_REGISTER_DRIVER);
	}

	void gameport_unregister_driver(struct gameport_driver *drv)
	{
	struct gameport *gameport;

	down(&gameport_sem);
	drv->ignore = 1; /* so gameport_find_driver ignores it */

	start_over:
	list_for_each_entry(gameport, &gameport_list, node) {
	if (gameport->drv == drv) {
	gameport_disconnect_port(gameport);
	gameport_find_driver(gameport);
	/* we could've deleted some ports, restart */
	goto start_over;
	}
	}

	driver_unregister(&drv->driver);
	up(&gameport_sem);
	}

	static int gameport_bus_match(struct device dev, struct device_driver drv)
	{
	struct gameport_driver *gameport_drv = to_gameport_driver(drv);

	return !gameport_drv->ignore;
	}

	static void gameport_set_drv(struct gameport gameport, struct gameport_driver drv)
	{
	down(&gameport->drv_sem);
	gameport->drv = drv;
	up(&gameport->drv_sem);
	}

	int gameport_open(struct gameport gameport, struct gameport_driver drv, int mode)
	{

	if (gameport->open) {
	if (gameport->open(gameport, mode)) {
	return -1;
	}
	} else {
	if (mode != GAMEPORT_MODE_RAW)
	return -1;
	}

	gameport_set_drv(gameport, drv);
	return 0;
	}

	void gameport_close(struct gameport *gameport)
	{
	del_timer_sync(&gameport->poll_timer);
	gameport->poll_handler = NULL;
	gameport->poll_interval = 0;
	gameport_set_drv(gameport, NULL);
	if (gameport->close)
	gameport->close(gameport);
	}

	static int __init gameport_init(void)
	{
	gameport_task = kthread_run(gameport_thread, NULL, "kgameportd");
	if (IS_ERR(gameport_task)) {
	printk(KERN_ERR "gameport: Failed to start kgameportd\n");
	return PTR_ERR(gameport_task);
	}

	gameport_bus.dev_attrs = gameport_device_attrs;
	gameport_bus.drv_attrs = gameport_driver_attrs;
	gameport_bus.match = gameport_bus_match;
	bus_register(&gameport_bus);

	return 0;
	}

	static void __exit gameport_exit(void)
	{
	bus_unregister(&gameport_bus);
	kthread_stop(gameport_task);
	}

	module_init(gameport_init);
	module_exit(gameport_exit);