Linux-2.6.12-rc2

[mirror_ubuntu-artful-kernel.git] / drivers / input / gameport / gameport.c

/*
 * 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/completion.h>
#include <linux/sched.h>
#include <linux/smp_lock.h>
#include <linux/slab.h>
#include <linux/delay.h>

/*#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__)

#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)
{
        extern spinlock_t i8253_lock;
        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[_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 DECLARE_COMPLETION(gameport_exited);
static int gameport_pid;

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_events(void)
{
        struct gameport_event *event;
        struct gameport_driver *gameport_drv;

        down(&gameport_sem);

        while ((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)
{
        lock_kernel();
        daemonize("kgameportd");
        allow_signal(SIGTERM);

        do {
                gameport_handle_events();
                wait_event_interruptible(gameport_wait, !list_empty(&gameport_event_list));
                try_to_freeze(PF_FREEZE);
        } while (!signal_pending(current));

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

        unlock_kernel();
        complete_and_exit(&gameport_exited, 0);
}


/*
 * Gameport port operations
 */

static ssize_t gameport_show_description(struct device *dev, 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, 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)
{
        if (!(gameport_pid = kernel_thread(gameport_thread, NULL, CLONE_KERNEL))) {
                printk(KERN_ERR "gameport: Failed to start kgameportd\n");
                return -1;
        }

        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);
        kill_proc(gameport_pid, SIGTERM, 1);
        wait_for_completion(&gameport_exited);
}

module_init(gameport_init);
module_exit(gameport_exit);