net/irda/irda_device.c - kernel/msm-4.9 - Gitiles

 /*********************************************************************
  *
  * Filename:      irda_device.c
  * Version:       0.9
  * Description:   Utility functions used by the device drivers
  * Status:        Experimental.
  * Author:        Dag Brattli <dagb@cs.uit.no>
  * Created at:    Sat Oct  9 09:22:27 1999
  * Modified at:   Sun Jan 23 17:41:24 2000
  * Modified by:   Dag Brattli <dagb@cs.uit.no>
  *
  *     Copyright (c) 1999-2000 Dag Brattli, All Rights Reserved.
  *     Copyright (c) 2000-2001 Jean Tourrilhes <jt@hpl.hp.com>
  *
  *     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
  *
  ********************************************************************/

 #include <linux/string.h>
 #include <linux/proc_fs.h>
 #include <linux/skbuff.h>
 #include <linux/capability.h>
 #include <linux/if.h>
 #include <linux/if_ether.h>
 #include <linux/if_arp.h>
 #include <linux/netdevice.h>
 #include <linux/init.h>
 #include <linux/tty.h>
 #include <linux/kmod.h>
 #include <linux/spinlock.h>

 #include <asm/ioctls.h>
 #include <asm/uaccess.h>
 #include <asm/dma.h>
 #include <asm/io.h>

 #include <net/irda/irda_device.h>
 #include <net/irda/irlap.h>
 #include <net/irda/timer.h>
 #include <net/irda/wrapper.h>

 static void __irda_task_delete(struct irda_task *task);

 static hashbin_t *dongles = NULL;
 static hashbin_t *tasks = NULL;

 #ifdef CONFIG_IRDA_DEBUG
 static const char *task_state[] = {
 	"IRDA_TASK_INIT",
 	"IRDA_TASK_DONE",
 	"IRDA_TASK_WAIT",
 	"IRDA_TASK_WAIT1",
 	"IRDA_TASK_WAIT2",
 	"IRDA_TASK_WAIT3",
 	"IRDA_TASK_CHILD_INIT",
 	"IRDA_TASK_CHILD_WAIT",
 	"IRDA_TASK_CHILD_DONE",
 };
 #endif	/* CONFIG_IRDA_DEBUG */

 static void irda_task_timer_expired(void *data);

 int __init irda_device_init( void)
 {
 	dongles = hashbin_new(HB_NOLOCK);
 	if (dongles == NULL) {
 		IRDA_WARNING("IrDA: Can't allocate dongles hashbin!\n");
 		return -ENOMEM;
 	}
 	spin_lock_init(&dongles->hb_spinlock);

 	tasks = hashbin_new(HB_LOCK);
 	if (tasks == NULL) {
 		IRDA_WARNING("IrDA: Can't allocate tasks hashbin!\n");
 		hashbin_delete(dongles, NULL);
 		return -ENOMEM;
 	}

 	/* We no longer initialise the driver ourselves here, we let
 	 * the system do it for us... - Jean II */

 	return 0;
 }

 static void __exit leftover_dongle(void *arg)
 {
 	struct dongle_reg *reg = arg;
 	IRDA_WARNING("IrDA: Dongle type %x not unregistered\n",
 		     reg->type);
 }

 void __exit irda_device_cleanup(void)
 {
 	IRDA_DEBUG(4, "%s()\n", __FUNCTION__);

 	hashbin_delete(tasks, (FREE_FUNC) __irda_task_delete);

 	hashbin_delete(dongles, leftover_dongle);
 }

 /*
  * Function irda_device_set_media_busy (self, status)
  *
  *    Called when we have detected that another station is transmitting
  *    in contention mode.
  */
 void irda_device_set_media_busy(struct net_device *dev, int status)
 {
 	struct irlap_cb *self;

 	IRDA_DEBUG(4, "%s(%s)\n", __FUNCTION__, status ? "TRUE" : "FALSE");

 	self = (struct irlap_cb *) dev->atalk_ptr;

 	/* Some drivers may enable the receive interrupt before calling
 	 * irlap_open(), or they may disable the receive interrupt
 	 * after calling irlap_close().
 	 * The IrDA stack is protected from this in irlap_driver_rcv().
 	 * However, the driver calls directly the wrapper, that calls
 	 * us directly. Make sure we protect ourselves.
 	 * Jean II */
 	if (!self || self->magic != LAP_MAGIC)
 		return;

 	if (status) {
 		self->media_busy = TRUE;
 		if (status == SMALL)
 			irlap_start_mbusy_timer(self, SMALLBUSY_TIMEOUT);
 		else
 			irlap_start_mbusy_timer(self, MEDIABUSY_TIMEOUT);
 		IRDA_DEBUG( 4, "Media busy!\n");
 	} else {
 		self->media_busy = FALSE;
 		irlap_stop_mbusy_timer(self);
 	}
 }
 EXPORT_SYMBOL(irda_device_set_media_busy);


 /*
  * Function irda_device_is_receiving (dev)
  *
  *    Check if the device driver is currently receiving data
  *
  */
 int irda_device_is_receiving(struct net_device *dev)
 {
 	struct if_irda_req req;
 	int ret;

 	IRDA_DEBUG(2, "%s()\n", __FUNCTION__);

 	if (!dev->do_ioctl) {
 		IRDA_ERROR("%s: do_ioctl not impl. by device driver\n",
 			   __FUNCTION__);
 		return -1;
 	}

 	ret = dev->do_ioctl(dev, (struct ifreq *) &req, SIOCGRECEIVING);
 	if (ret < 0)
 		return ret;

 	return req.ifr_receiving;
 }

 void irda_task_next_state(struct irda_task *task, IRDA_TASK_STATE state)
 {
 	IRDA_DEBUG(2, "%s(), state = %s\n", __FUNCTION__, task_state[state]);

 	task->state = state;
 }
 EXPORT_SYMBOL(irda_task_next_state);

 static void __irda_task_delete(struct irda_task *task)
 {
 	del_timer(&task->timer);

 	kfree(task);
 }

 void irda_task_delete(struct irda_task *task)
 {
 	/* Unregister task */
 	hashbin_remove(tasks, (long) task, NULL);

 	__irda_task_delete(task);
 }
 EXPORT_SYMBOL(irda_task_delete);

 /*
  * Function irda_task_kick (task)
  *
  *    Tries to execute a task possible multiple times until the task is either
  *    finished, or askes for a timeout. When a task is finished, we do post
  *    processing, and notify the parent task, that is waiting for this task
  *    to complete.
  */
 static int irda_task_kick(struct irda_task *task)
 {
 	int finished = TRUE;
 	int count = 0;
 	int timeout;

 	IRDA_DEBUG(2, "%s()\n", __FUNCTION__);

 	IRDA_ASSERT(task != NULL, return -1;);
 	IRDA_ASSERT(task->magic == IRDA_TASK_MAGIC, return -1;);

 	/* Execute task until it's finished, or askes for a timeout */
 	do {
 		timeout = task->function(task);
 		if (count++ > 100) {
 			IRDA_ERROR("%s: error in task handler!\n",
 				   __FUNCTION__);
 			irda_task_delete(task);
 			return TRUE;
 		}
 	} while ((timeout == 0) && (task->state != IRDA_TASK_DONE));

 	if (timeout < 0) {
 		IRDA_ERROR("%s: Error executing task!\n", __FUNCTION__);
 		irda_task_delete(task);
 		return TRUE;
 	}

 	/* Check if we are finished */
 	if (task->state == IRDA_TASK_DONE) {
 		del_timer(&task->timer);

 		/* Do post processing */
 		if (task->finished)
 			task->finished(task);

 		/* Notify parent */
 		if (task->parent) {
 			/* Check if parent is waiting for us to complete */
 			if (task->parent->state == IRDA_TASK_CHILD_WAIT) {
 				task->parent->state = IRDA_TASK_CHILD_DONE;

 				/* Stop timer now that we are here */
 				del_timer(&task->parent->timer);

 				/* Kick parent task */
 				irda_task_kick(task->parent);
 			}
 		}
 		irda_task_delete(task);
 	} else if (timeout > 0) {
 		irda_start_timer(&task->timer, timeout, (void *) task,
 				 irda_task_timer_expired);
 		finished = FALSE;
 	} else {
 		IRDA_DEBUG(0, "%s(), not finished, and no timeout!\n",
 			   __FUNCTION__);
 		finished = FALSE;
 	}

 	return finished;
 }

 /*
  * Function irda_task_execute (instance, function, finished)
  *
  *    This function registers and tries to execute tasks that may take some
  *    time to complete. We do it this hairy way since we may have been
  *    called from interrupt context, so it's not possible to use
  *    schedule_timeout()
  * Two important notes :
  *	o Make sure you irda_task_delete(task); in case you delete the
  *	  calling instance.
  *	o No real need to lock when calling this function, but you may
  *	  want to lock within the task handler.
  * Jean II
  */
 struct irda_task *irda_task_execute(void *instance,
 				    IRDA_TASK_CALLBACK function,
 				    IRDA_TASK_CALLBACK finished,
 				    struct irda_task *parent, void *param)
 {
 	struct irda_task *task;

 	IRDA_DEBUG(2, "%s()\n", __FUNCTION__);

 	task = kmalloc(sizeof(struct irda_task), GFP_ATOMIC);
 	if (!task)
 		return NULL;

 	task->state    = IRDA_TASK_INIT;
 	task->instance = instance;
 	task->function = function;
 	task->finished = finished;
 	task->parent   = parent;
 	task->param    = param;
 	task->magic    = IRDA_TASK_MAGIC;

 	init_timer(&task->timer);

 	/* Register task */
 	hashbin_insert(tasks, (irda_queue_t *) task, (long) task, NULL);

 	/* No time to waste, so lets get going! */
 	return irda_task_kick(task) ? NULL : task;
 }
 EXPORT_SYMBOL(irda_task_execute);

 /*
  * Function irda_task_timer_expired (data)
  *
  *    Task time has expired. We now try to execute task (again), and restart
  *    the timer if the task has not finished yet
  */
 static void irda_task_timer_expired(void *data)
 {
 	struct irda_task *task;

 	IRDA_DEBUG(2, "%s()\n", __FUNCTION__);

 	task = (struct irda_task *) data;

 	irda_task_kick(task);
 }

 /*
  * Function irda_device_setup (dev)
  *
  *    This function should be used by low level device drivers in a similar way
  *    as ether_setup() is used by normal network device drivers
  */
 static void irda_device_setup(struct net_device *dev)
 {
 	dev->hard_header_len = 0;
 	dev->addr_len        = LAP_ALEN;

 	dev->type            = ARPHRD_IRDA;
 	dev->tx_queue_len    = 8; /* Window size + 1 s-frame */

 	memset(dev->broadcast, 0xff, LAP_ALEN);

 	dev->mtu = 2048;
 	dev->flags = IFF_NOARP;
 }

 /*
  * Funciton  alloc_irdadev
  * 	Allocates and sets up an IRDA device in a manner similar to
  * 	alloc_etherdev.
  */
 struct net_device *alloc_irdadev(int sizeof_priv)
 {
 	return alloc_netdev(sizeof_priv, "irda%d", irda_device_setup);
 }
 EXPORT_SYMBOL(alloc_irdadev);

 /*
  * Function irda_device_init_dongle (self, type, qos)
  *
  *    Initialize attached dongle.
  *
  * Important : request_module require us to call this function with
  * a process context and irq enabled. - Jean II
  */
 dongle_t *irda_device_dongle_init(struct net_device *dev, int type)
 {
 	struct dongle_reg *reg;
 	dongle_t *dongle = kzalloc(sizeof(dongle_t), GFP_KERNEL);

 	might_sleep();

 	spin_lock(&dongles->hb_spinlock);
 	reg = hashbin_find(dongles, type, NULL);

 #ifdef CONFIG_KMOD
 	/* Try to load the module needed */
 	if (!reg && capable(CAP_SYS_MODULE)) {
 		spin_unlock(&dongles->hb_spinlock);

 		request_module("irda-dongle-%d", type);

 		spin_lock(&dongles->hb_spinlock);
 		reg = hashbin_find(dongles, type, NULL);
 	}
 #endif

 	if (!reg || !try_module_get(reg->owner) ) {
 		IRDA_ERROR("IrDA: Unable to find requested dongle type %x\n",
 			   type);
 		kfree(dongle);
 		dongle = NULL;
 	}
 	if (dongle) {
 		/* Bind the registration info to this particular instance */
 		dongle->issue = reg;
 		dongle->dev = dev;
 	}
 	spin_unlock(&dongles->hb_spinlock);
 	return dongle;
 }
 EXPORT_SYMBOL(irda_device_dongle_init);

 /*
  * Function irda_device_dongle_cleanup (dongle)
  */
 int irda_device_dongle_cleanup(dongle_t *dongle)
 {
 	IRDA_ASSERT(dongle != NULL, return -1;);

 	dongle->issue->close(dongle);
 	module_put(dongle->issue->owner);
 	kfree(dongle);

 	return 0;
 }
 EXPORT_SYMBOL(irda_device_dongle_cleanup);

 /*
  * Function irda_device_register_dongle (dongle)
  */
 int irda_device_register_dongle(struct dongle_reg *new)
 {
 	spin_lock(&dongles->hb_spinlock);
 	/* Check if this dongle has been registered before */
 	if (hashbin_find(dongles, new->type, NULL)) {
 		IRDA_MESSAGE("%s: Dongle type %x already registered\n",
 			     __FUNCTION__, new->type);
 	} else {
 		/* Insert IrDA dongle into hashbin */
 		hashbin_insert(dongles, (irda_queue_t *) new, new->type, NULL);
 	}
 	spin_unlock(&dongles->hb_spinlock);

 	return 0;
 }
 EXPORT_SYMBOL(irda_device_register_dongle);

 /*
  * Function irda_device_unregister_dongle (dongle)
  *
  *    Unregister dongle, and remove dongle from list of registered dongles
  *
  */
 void irda_device_unregister_dongle(struct dongle_reg *dongle)
 {
 	struct dongle *node;

 	spin_lock(&dongles->hb_spinlock);
 	node = hashbin_remove(dongles, dongle->type, NULL);
 	if (!node)
 		IRDA_ERROR("%s: dongle not found!\n", __FUNCTION__);
 	spin_unlock(&dongles->hb_spinlock);
 }
 EXPORT_SYMBOL(irda_device_unregister_dongle);

 #ifdef CONFIG_ISA_DMA_API
 /*
  * Function setup_dma (idev, buffer, count, mode)
  *
  *    Setup the DMA channel. Commonly used by LPC FIR drivers
  *
  */
 void irda_setup_dma(int channel, dma_addr_t buffer, int count, int mode)
 {
 	unsigned long flags;

 	flags = claim_dma_lock();

 	disable_dma(channel);
 	clear_dma_ff(channel);
 	set_dma_mode(channel, mode);
 	set_dma_addr(channel, buffer);
 	set_dma_count(channel, count);
 	enable_dma(channel);

 	release_dma_lock(flags);
 }
 EXPORT_SYMBOL(irda_setup_dma);
 #endif
	/*********************************************************************
	*
	* Filename: irda_device.c
	* Version: 0.9
	* Description: Utility functions used by the device drivers
	* Status: Experimental.
	* Author: Dag Brattli <dagb@cs.uit.no>
	* Created at: Sat Oct 9 09:22:27 1999
	* Modified at: Sun Jan 23 17:41:24 2000
	* Modified by: Dag Brattli <dagb@cs.uit.no>
	*
	* Copyright (c) 1999-2000 Dag Brattli, All Rights Reserved.
	* Copyright (c) 2000-2001 Jean Tourrilhes <jt@hpl.hp.com>
	*
	* 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
	*
	********************************************************************/

	#include <linux/string.h>
	#include <linux/proc_fs.h>
	#include <linux/skbuff.h>
	#include <linux/capability.h>
	#include <linux/if.h>
	#include <linux/if_ether.h>
	#include <linux/if_arp.h>
	#include <linux/netdevice.h>
	#include <linux/init.h>
	#include <linux/tty.h>
	#include <linux/kmod.h>
	#include <linux/spinlock.h>

	#include <asm/ioctls.h>
	#include <asm/uaccess.h>
	#include <asm/dma.h>
	#include <asm/io.h>

	#include <net/irda/irda_device.h>
	#include <net/irda/irlap.h>
	#include <net/irda/timer.h>
	#include <net/irda/wrapper.h>

	static void __irda_task_delete(struct irda_task *task);

	static hashbin_t *dongles = NULL;
	static hashbin_t *tasks = NULL;

	#ifdef CONFIG_IRDA_DEBUG
	static const char *task_state[] = {
	"IRDA_TASK_INIT",
	"IRDA_TASK_DONE",
	"IRDA_TASK_WAIT",
	"IRDA_TASK_WAIT1",
	"IRDA_TASK_WAIT2",
	"IRDA_TASK_WAIT3",
	"IRDA_TASK_CHILD_INIT",
	"IRDA_TASK_CHILD_WAIT",
	"IRDA_TASK_CHILD_DONE",
	};
	#endif /* CONFIG_IRDA_DEBUG */

	static void irda_task_timer_expired(void *data);

	int __init irda_device_init( void)
	{
	dongles = hashbin_new(HB_NOLOCK);
	if (dongles == NULL) {
	IRDA_WARNING("IrDA: Can't allocate dongles hashbin!\n");
	return -ENOMEM;
	}
	spin_lock_init(&dongles->hb_spinlock);

	tasks = hashbin_new(HB_LOCK);
	if (tasks == NULL) {
	IRDA_WARNING("IrDA: Can't allocate tasks hashbin!\n");
	hashbin_delete(dongles, NULL);
	return -ENOMEM;
	}

	/* We no longer initialise the driver ourselves here, we let
	* the system do it for us... - Jean II */

	return 0;
	}

	static void __exit leftover_dongle(void *arg)
	{
	struct dongle_reg *reg = arg;
	IRDA_WARNING("IrDA: Dongle type %x not unregistered\n",
	reg->type);
	}

	void __exit irda_device_cleanup(void)
	{
	IRDA_DEBUG(4, "%s()\n", __FUNCTION__);

	hashbin_delete(tasks, (FREE_FUNC) __irda_task_delete);

	hashbin_delete(dongles, leftover_dongle);
	}

	/*
	* Function irda_device_set_media_busy (self, status)
	*
	* Called when we have detected that another station is transmitting
	* in contention mode.
	*/
	void irda_device_set_media_busy(struct net_device *dev, int status)
	{
	struct irlap_cb *self;

	IRDA_DEBUG(4, "%s(%s)\n", __FUNCTION__, status ? "TRUE" : "FALSE");

	self = (struct irlap_cb *) dev->atalk_ptr;

	/* Some drivers may enable the receive interrupt before calling
	* irlap_open(), or they may disable the receive interrupt
	* after calling irlap_close().
	* The IrDA stack is protected from this in irlap_driver_rcv().
	* However, the driver calls directly the wrapper, that calls
	* us directly. Make sure we protect ourselves.
	* Jean II */
	if (!self \|\| self->magic != LAP_MAGIC)
	return;

	if (status) {
	self->media_busy = TRUE;
	if (status == SMALL)
	irlap_start_mbusy_timer(self, SMALLBUSY_TIMEOUT);
	else
	irlap_start_mbusy_timer(self, MEDIABUSY_TIMEOUT);
	IRDA_DEBUG( 4, "Media busy!\n");
	} else {
	self->media_busy = FALSE;
	irlap_stop_mbusy_timer(self);
	}
	}
	EXPORT_SYMBOL(irda_device_set_media_busy);


	/*
	* Function irda_device_is_receiving (dev)
	*
	* Check if the device driver is currently receiving data
	*
	*/
	int irda_device_is_receiving(struct net_device *dev)
	{
	struct if_irda_req req;
	int ret;

	IRDA_DEBUG(2, "%s()\n", __FUNCTION__);

	if (!dev->do_ioctl) {
	IRDA_ERROR("%s: do_ioctl not impl. by device driver\n",
	__FUNCTION__);
	return -1;
	}

	ret = dev->do_ioctl(dev, (struct ifreq *) &req, SIOCGRECEIVING);
	if (ret < 0)
	return ret;

	return req.ifr_receiving;
	}

	void irda_task_next_state(struct irda_task *task, IRDA_TASK_STATE state)
	{
	IRDA_DEBUG(2, "%s(), state = %s\n", __FUNCTION__, task_state[state]);

	task->state = state;
	}
	EXPORT_SYMBOL(irda_task_next_state);

	static void __irda_task_delete(struct irda_task *task)
	{
	del_timer(&task->timer);

	kfree(task);
	}

	void irda_task_delete(struct irda_task *task)
	{
	/* Unregister task */
	hashbin_remove(tasks, (long) task, NULL);

	__irda_task_delete(task);
	}
	EXPORT_SYMBOL(irda_task_delete);

	/*
	* Function irda_task_kick (task)
	*
	* Tries to execute a task possible multiple times until the task is either
	* finished, or askes for a timeout. When a task is finished, we do post
	* processing, and notify the parent task, that is waiting for this task
	* to complete.
	*/
	static int irda_task_kick(struct irda_task *task)
	{
	int finished = TRUE;
	int count = 0;
	int timeout;

	IRDA_DEBUG(2, "%s()\n", __FUNCTION__);

	IRDA_ASSERT(task != NULL, return -1;);
	IRDA_ASSERT(task->magic == IRDA_TASK_MAGIC, return -1;);

	/* Execute task until it's finished, or askes for a timeout */
	do {
	timeout = task->function(task);
	if (count++ > 100) {
	IRDA_ERROR("%s: error in task handler!\n",
	__FUNCTION__);
	irda_task_delete(task);
	return TRUE;
	}
	} while ((timeout == 0) && (task->state != IRDA_TASK_DONE));

	if (timeout < 0) {
	IRDA_ERROR("%s: Error executing task!\n", __FUNCTION__);
	irda_task_delete(task);
	return TRUE;
	}

	/* Check if we are finished */
	if (task->state == IRDA_TASK_DONE) {
	del_timer(&task->timer);

	/* Do post processing */
	if (task->finished)
	task->finished(task);

	/* Notify parent */
	if (task->parent) {
	/* Check if parent is waiting for us to complete */
	if (task->parent->state == IRDA_TASK_CHILD_WAIT) {
	task->parent->state = IRDA_TASK_CHILD_DONE;

	/* Stop timer now that we are here */
	del_timer(&task->parent->timer);

	/* Kick parent task */
	irda_task_kick(task->parent);
	}
	}
	irda_task_delete(task);
	} else if (timeout > 0) {
	irda_start_timer(&task->timer, timeout, (void *) task,
	irda_task_timer_expired);
	finished = FALSE;
	} else {
	IRDA_DEBUG(0, "%s(), not finished, and no timeout!\n",
	__FUNCTION__);
	finished = FALSE;
	}

	return finished;
	}

	/*
	* Function irda_task_execute (instance, function, finished)
	*
	* This function registers and tries to execute tasks that may take some
	* time to complete. We do it this hairy way since we may have been
	* called from interrupt context, so it's not possible to use
	* schedule_timeout()
	* Two important notes :
	* o Make sure you irda_task_delete(task); in case you delete the
	* calling instance.
	* o No real need to lock when calling this function, but you may
	* want to lock within the task handler.
	* Jean II
	*/
	struct irda_task irda_task_execute(void instance,
	IRDA_TASK_CALLBACK function,
	IRDA_TASK_CALLBACK finished,
	struct irda_task parent, void param)
	{
	struct irda_task *task;

	IRDA_DEBUG(2, "%s()\n", __FUNCTION__);

	task = kmalloc(sizeof(struct irda_task), GFP_ATOMIC);
	if (!task)
	return NULL;

	task->state = IRDA_TASK_INIT;
	task->instance = instance;
	task->function = function;
	task->finished = finished;
	task->parent = parent;
	task->param = param;
	task->magic = IRDA_TASK_MAGIC;

	init_timer(&task->timer);

	/* Register task */
	hashbin_insert(tasks, (irda_queue_t *) task, (long) task, NULL);

	/* No time to waste, so lets get going! */
	return irda_task_kick(task) ? NULL : task;
	}
	EXPORT_SYMBOL(irda_task_execute);

	/*
	* Function irda_task_timer_expired (data)
	*
	* Task time has expired. We now try to execute task (again), and restart
	* the timer if the task has not finished yet
	*/
	static void irda_task_timer_expired(void *data)
	{
	struct irda_task *task;

	IRDA_DEBUG(2, "%s()\n", __FUNCTION__);

	task = (struct irda_task *) data;

	irda_task_kick(task);
	}

	/*
	* Function irda_device_setup (dev)
	*
	* This function should be used by low level device drivers in a similar way
	* as ether_setup() is used by normal network device drivers
	*/
	static void irda_device_setup(struct net_device *dev)
	{
	dev->hard_header_len = 0;
	dev->addr_len = LAP_ALEN;

	dev->type = ARPHRD_IRDA;
	dev->tx_queue_len = 8; /* Window size + 1 s-frame */

	memset(dev->broadcast, 0xff, LAP_ALEN);

	dev->mtu = 2048;
	dev->flags = IFF_NOARP;
	}

	/*
	* Funciton alloc_irdadev
	* Allocates and sets up an IRDA device in a manner similar to
	* alloc_etherdev.
	*/
	struct net_device *alloc_irdadev(int sizeof_priv)
	{
	return alloc_netdev(sizeof_priv, "irda%d", irda_device_setup);
	}
	EXPORT_SYMBOL(alloc_irdadev);

	/*
	* Function irda_device_init_dongle (self, type, qos)
	*
	* Initialize attached dongle.
	*
	* Important : request_module require us to call this function with
	* a process context and irq enabled. - Jean II
	*/
	dongle_t irda_device_dongle_init(struct net_device dev, int type)
	{
	struct dongle_reg *reg;
	dongle_t *dongle = kzalloc(sizeof(dongle_t), GFP_KERNEL);

	might_sleep();

	spin_lock(&dongles->hb_spinlock);
	reg = hashbin_find(dongles, type, NULL);

	#ifdef CONFIG_KMOD
	/* Try to load the module needed */
	if (!reg && capable(CAP_SYS_MODULE)) {
	spin_unlock(&dongles->hb_spinlock);

	request_module("irda-dongle-%d", type);

	spin_lock(&dongles->hb_spinlock);
	reg = hashbin_find(dongles, type, NULL);
	}
	#endif

	if (!reg \|\| !try_module_get(reg->owner) ) {
	IRDA_ERROR("IrDA: Unable to find requested dongle type %x\n",
	type);
	kfree(dongle);
	dongle = NULL;
	}
	if (dongle) {
	/* Bind the registration info to this particular instance */
	dongle->issue = reg;
	dongle->dev = dev;
	}
	spin_unlock(&dongles->hb_spinlock);
	return dongle;
	}
	EXPORT_SYMBOL(irda_device_dongle_init);

	/*
	* Function irda_device_dongle_cleanup (dongle)
	*/
	int irda_device_dongle_cleanup(dongle_t *dongle)
	{
	IRDA_ASSERT(dongle != NULL, return -1;);

	dongle->issue->close(dongle);
	module_put(dongle->issue->owner);
	kfree(dongle);

	return 0;
	}
	EXPORT_SYMBOL(irda_device_dongle_cleanup);

	/*
	* Function irda_device_register_dongle (dongle)
	*/
	int irda_device_register_dongle(struct dongle_reg *new)
	{
	spin_lock(&dongles->hb_spinlock);
	/* Check if this dongle has been registered before */
	if (hashbin_find(dongles, new->type, NULL)) {
	IRDA_MESSAGE("%s: Dongle type %x already registered\n",
	__FUNCTION__, new->type);
	} else {
	/* Insert IrDA dongle into hashbin */
	hashbin_insert(dongles, (irda_queue_t *) new, new->type, NULL);
	}
	spin_unlock(&dongles->hb_spinlock);

	return 0;
	}
	EXPORT_SYMBOL(irda_device_register_dongle);

	/*
	* Function irda_device_unregister_dongle (dongle)
	*
	* Unregister dongle, and remove dongle from list of registered dongles
	*
	*/
	void irda_device_unregister_dongle(struct dongle_reg *dongle)
	{
	struct dongle *node;

	spin_lock(&dongles->hb_spinlock);
	node = hashbin_remove(dongles, dongle->type, NULL);
	if (!node)
	IRDA_ERROR("%s: dongle not found!\n", __FUNCTION__);
	spin_unlock(&dongles->hb_spinlock);
	}
	EXPORT_SYMBOL(irda_device_unregister_dongle);

	#ifdef CONFIG_ISA_DMA_API
	/*
	* Function setup_dma (idev, buffer, count, mode)
	*
	* Setup the DMA channel. Commonly used by LPC FIR drivers
	*
	*/
	void irda_setup_dma(int channel, dma_addr_t buffer, int count, int mode)
	{
	unsigned long flags;

	flags = claim_dma_lock();

	disable_dma(channel);
	clear_dma_ff(channel);
	set_dma_mode(channel, mode);
	set_dma_addr(channel, buffer);
	set_dma_count(channel, count);
	enable_dma(channel);

	release_dma_lock(flags);
	}
	EXPORT_SYMBOL(irda_setup_dma);
	#endif