gameport.c

linux-2.6.15.6

/*
 * 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 <[e-mail]>");
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) {