serio.c

QQ2440板子

/*
 *  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 <[e-mail]>, 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>

MODULE_AUTHOR("Vojtech Pavlik <[e-mail]>");
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_unregister_port_delayed);
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_sem protects entire serio subsystem and is taken every time
 * serio port or driver registrered or unregistered.
 */
static DECLARE_MUTEX(serio_sem);

static LIST_HEAD(serio_list);

static struct bus_type serio_bus = {
	.name =	"serio",
};

static void serio_add_port(struct serio *serio);
static void serio_destroy_port(struct serio *serio);
static void serio_reconnect_port(struct serio *serio);
static void serio_disconnect_port(struct serio *serio);

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

	down(&serio->drv_sem);
	retval = drv->connect(serio, drv);
	up(&serio->drv_sem);

	return retval;
}

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

	down(&serio->drv_sem);
	if (serio->drv && serio->drv->reconnect)
		retval = serio->drv->reconnect(serio);
	up(&serio->drv_sem);

	return retval;
}

static void serio_disconnect_driver(struct serio *serio)
{
	down(&serio->drv_sem);
	if (serio->drv)
		serio->drv->disconnect(serio);
	up(&serio->drv_sem);
}

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 void serio_bind_driver(struct serio *serio, struct serio_driver *drv)
{
	down_write(&serio_bus.subsys.rwsem);

	if (serio_match_port(drv->id_table, serio)) {
		serio->dev.driver = &drv->driver;
		if (serio_connect_driver(serio, drv)) {
			serio->dev.driver = NULL;
			goto out;
		}
		device_bind_driver(&serio->dev);
	}
out:
	up_write(&serio_bus.subsys.rwsem);
}

static void serio_release_driver(struct serio *serio)
{
	down_write(&serio_bus.subsys.rwsem);
	device_release_driver(&serio->dev);
	up_write(&serio_bus.subsys.rwsem);
}

static void serio_find_driver(struct serio *serio)
{
	down_write(&serio_bus.subsys.rwsem);
	device_attach(&serio->dev);
	up_write(&serio_bus.subsys.rwsem);
}


/*
 * Serio event processing.
 */

enum serio_event_type {
	SERIO_RESCAN,
	SERIO_RECONNECT,
	SERIO_REGISTER_PORT,
	SERIO_UNREGISTER_PORT,
	SERIO_REGISTER_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 void serio_queue_event(void *object, struct module *owner,
			      enum serio_event_type event_type)
{
	unsigned long flags;
	struct serio_event *event;

	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;
		}
	}

	if ((event = kmalloc(sizeof(struct serio_event), GFP_ATOMIC))) {
		if (!try_module_get(owner)) {
			printk(KERN_WARNING "serio: 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, &serio_event_list);
		wake_up(&serio_wait);
	} else {
		printk(KERN_ERR "serio: Not enough memory to queue event %d\n", event_type);
	}
out:
	spin_unlock_irqrestore(&serio_event_lock, flags);
}

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_events(void)
{
	struct serio_event *event;
	struct serio_driver *serio_drv;

	down(&serio_sem);

	while ((event = serio_get_event())) {

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

			case SERIO_UNREGISTER_PORT:
				serio_disconnect_port(event->object);
				serio_destroy_port(event->object);
				break;

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

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

			case SERIO_REGISTER_DRIVER:
				serio_drv = event->object;
				driver_register(&serio_drv->driver);
				break;

			default:
				break;
		}

		serio_remove_duplicate_events(event);
		serio_free_event(event);
	}

	up(&serio_sem);
}

/*
 * 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)
{
	do {
		serio_handle_events();
		wait_event_interruptible(serio_wait,
			kthread_should_stop() || !list_empty(&serio_event_list));
		try_to_freeze();
	} 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 retval;

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

	retval = count;
	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) {