serio.c

h内核

static void serio_destroy_port(struct serio *serio)
{
	struct serio_driver *drv = serio->drv;
	unsigned long flags;

	serio_remove_pending_events(serio);
	list_del_init(&serio->node);

	if (drv) {
		drv->disconnect(serio);
		down_write(&serio_bus.subsys.rwsem);
		device_release_driver(&serio->dev);
		up_write(&serio_bus.subsys.rwsem);
		put_driver(&drv->driver);
	}

	if (serio->parent) {
		spin_lock_irqsave(&serio->parent->lock, flags);
		serio->parent->child = NULL;
		spin_unlock_irqrestore(&serio->parent->lock, flags);
	}

	device_unregister(&serio->dev);
}

/*
 * serio_connect_port() tries to bind the port and possible all its
 * children to appropriate drivers. If driver passed in the function will not
 * try otehr drivers when binding parent port.
 */
static void serio_connect_port(struct serio *serio, struct serio_driver *drv)
{
	WARN_ON(serio->drv);
	WARN_ON(serio->child);

	if (drv)
		serio_bind_driver(serio, drv);
	else if (!serio->manual_bind)
		serio_find_driver(serio);

	/* Ok, now bind children, if any */
	while (serio->child) {
		serio = serio->child;

		WARN_ON(serio->drv);
		WARN_ON(serio->child);

		serio_create_port(serio);

		if (!serio->manual_bind) {
			/*
			 * With children we just _prefer_ passed in driver,
			 * but we will try other options in case preferred
			 * is not the one
			 */
			if (!drv || !serio_bind_driver(serio, drv))
				serio_find_driver(serio);
		}
	}
}

/*
 *
 */
static void serio_reconnect_port(struct serio *serio)
{
	do {
		if (!serio->drv || !serio->drv->reconnect || serio->drv->reconnect(serio)) {
			serio_disconnect_port(serio);
			serio_connect_port(serio, NULL);
			/* 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_driver *drv = serio->drv;
	struct serio *s;

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

		while (s != serio) {
			s = s->parent;
			serio_destroy_port(s->child);
		}
	}

	/*
	 * Ok, no children left, now disconnect this port
	 */
	if (drv) {
		drv->disconnect(serio);
		down_write(&serio_bus.subsys.rwsem);
		device_release_driver(&serio->dev);
		up_write(&serio_bus.subsys.rwsem);
		put_driver(&drv->driver);
	}
}

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

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

void serio_register_port(struct serio *serio)
{
	down(&serio_sem);
	serio_create_port(serio);
	serio_connect_port(serio, NULL);
	up(&serio_sem);
}

/*
 * Submits register request to kseriod for subsequent execution.
 * Can be used when it is not obvious whether the serio_sem is
 * taken or not and when delayed execution is feasible.
 */
void serio_register_port_delayed(struct serio *serio)
{
	serio_queue_event(serio, SERIO_REGISTER_PORT);
}

void serio_unregister_port(struct serio *serio)
{
	down(&serio_sem);
	serio_disconnect_port(serio);
	serio_destroy_port(serio);
	up(&serio_sem);
}

/*
 * Submits unregister request to kseriod for subsequent execution.
 * Can be used when it is not obvious whether the serio_sem is
 * taken or not and when delayed execution is feasible.
 */
void serio_unregister_port_delayed(struct serio *serio)
{
	serio_queue_event(serio, SERIO_UNREGISTER_PORT);
}


/*
 * 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
};

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

	down(&serio_sem);

	list_add_tail(&drv->node, &serio_driver_list);

	drv->driver.bus = &serio_bus;
	driver_register(&drv->driver);

	if (drv->manual_bind)
		goto out;

start_over:
	list_for_each_entry(serio, &serio_list, node) {
		if (!serio->drv) {
			serio_connect_port(serio, drv);
			/*
			 * if new child appeared then the list is changed,
			 * we need to start over
			 */
			if (serio->child)
				goto start_over;
		}
	}

out:
	up(&serio_sem);
}

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

	down(&serio_sem);

	list_del_init(&drv->node);

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

	driver_unregister(&drv->driver);

	up(&serio_sem);
}

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

/* called from serio_driver->connect/disconnect methods under serio_sem */
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_sem */
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, struct pt_regs *regs)
{
	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, regs);
	} else {
		if (!dfl) {
			if ((serio->type != SERIO_8042 &&
			     serio->type != SERIO_8042_XL) || (data == 0xaa)) {
				serio_rescan(serio);
				ret = IRQ_HANDLED;
			}
		}
	}

	spin_unlock_irqrestore(&serio->lock, flags);

	return ret;
}

static int __init serio_init(void)
{
	if (!(serio_pid = kernel_thread(serio_thread, NULL, CLONE_KERNEL))) {
		printk(KERN_WARNING "serio: Failed to start kseriod\n");
		return -1;
	}

	serio_bus.dev_attrs = serio_device_attrs;
	serio_bus.drv_attrs = serio_driver_attrs;
	bus_register(&serio_bus);

	return 0;
}

static void __exit serio_exit(void)
{
	bus_unregister(&serio_bus);
	kill_proc(serio_pid, SIGTERM, 1);
	wait_for_completion(&serio_exited);
}

module_init(serio_init);
module_exit(serio_exit);