drivers/uwb/wlp/wlp-lc.c - maze/linux - Git at Google

 /*
  * WiMedia Logical Link Control Protocol (WLP)
  *
  * Copyright (C) 2005-2006 Intel Corporation
  * Reinette Chatre <reinette.chatre@intel.com>
  *
  * 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.
  *
  * 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., 51 Franklin Street, Fifth Floor, Boston, MA
  * 02110-1301, USA.
  *
  *
  * FIXME: docs
  */
 #include <linux/wlp.h>

 #include "wlp-internal.h"

 static
 void wlp_neighbor_init(struct wlp_neighbor_e *neighbor)
 {
 	INIT_LIST_HEAD(&neighbor->wssid);
 }

 /**
  * Create area for device information storage
  *
  * wlp->mutex must be held
  */
 int __wlp_alloc_device_info(struct wlp *wlp)
 {
 	struct device *dev = &wlp->rc->uwb_dev.dev;
 	BUG_ON(wlp->dev_info != NULL);
 	wlp->dev_info = kzalloc(sizeof(struct wlp_device_info), GFP_KERNEL);
 	if (wlp->dev_info == NULL) {
 		dev_err(dev, "WLP: Unable to allocate memory for "
 			"device information.\n");
 		return -ENOMEM;
 	}
 	return 0;
 }


 /**
  * Fill in device information using function provided by driver
  *
  * wlp->mutex must be held
  */
 static
 void __wlp_fill_device_info(struct wlp *wlp)
 {
 	wlp->fill_device_info(wlp, wlp->dev_info);
 }

 /**
  * Setup device information
  *
  * Allocate area for device information and populate it.
  *
  * wlp->mutex must be held
  */
 int __wlp_setup_device_info(struct wlp *wlp)
 {
 	int result;
 	struct device *dev = &wlp->rc->uwb_dev.dev;

 	result = __wlp_alloc_device_info(wlp);
 	if (result < 0) {
 		dev_err(dev, "WLP: Unable to allocate area for "
 			"device information.\n");
 		return result;
 	}
 	__wlp_fill_device_info(wlp);
 	return 0;
 }

 /**
  * Remove information about neighbor stored temporarily
  *
  * Information learned during discovey should only be stored when the
  * device enrolls in the neighbor's WSS. We do need to store this
  * information temporarily in order to present it to the user.
  *
  * We are only interested in keeping neighbor WSS information if that
  * neighbor is accepting enrollment.
  *
  * should be called with wlp->nbmutex held
  */
 void wlp_remove_neighbor_tmp_info(struct wlp_neighbor_e *neighbor)
 {
 	struct wlp_wssid_e *wssid_e, *next;
 	u8 keep;
 	if (!list_empty(&neighbor->wssid)) {
 		list_for_each_entry_safe(wssid_e, next, &neighbor->wssid,
 					 node) {
 			if (wssid_e->info != NULL) {
 				keep = wssid_e->info->accept_enroll;
 				kfree(wssid_e->info);
 				wssid_e->info = NULL;
 				if (!keep) {
 					list_del(&wssid_e->node);
 					kfree(wssid_e);
 				}
 			}
 		}
 	}
 	if (neighbor->info != NULL) {
 		kfree(neighbor->info);
 		neighbor->info = NULL;
 	}
 }

 /*
  * Populate WLP neighborhood cache with neighbor information
  *
  * A new neighbor is found. If it is discoverable then we add it to the
  * neighborhood cache.
  *
  */
 static
 int wlp_add_neighbor(struct wlp *wlp, struct uwb_dev *dev)
 {
 	int result = 0;
 	int discoverable;
 	struct wlp_neighbor_e *neighbor;

 	/*
 	 * FIXME:
 	 * Use contents of WLP IE found in beacon cache to determine if
 	 * neighbor is discoverable.
 	 * The device does not support WLP IE yet so this still needs to be
 	 * done. Until then we assume all devices are discoverable.
 	 */
 	discoverable = 1; /* will be changed when FIXME disappears */
 	if (discoverable) {
 		/* Add neighbor to cache for discovery */
 		neighbor = kzalloc(sizeof(*neighbor), GFP_KERNEL);
 		if (neighbor == NULL) {
 			dev_err(&dev->dev, "Unable to create memory for "
 				"new neighbor. \n");
 			result = -ENOMEM;
 			goto error_no_mem;
 		}
 		wlp_neighbor_init(neighbor);
 		uwb_dev_get(dev);
 		neighbor->uwb_dev = dev;
 		list_add(&neighbor->node, &wlp->neighbors);
 	}
 error_no_mem:
 	return result;
 }

 /**
  * Remove one neighbor from cache
  */
 static
 void __wlp_neighbor_release(struct wlp_neighbor_e *neighbor)
 {
 	struct wlp_wssid_e *wssid_e, *next_wssid_e;

 	list_for_each_entry_safe(wssid_e, next_wssid_e,
 				 &neighbor->wssid, node) {
 		list_del(&wssid_e->node);
 		kfree(wssid_e);
 	}
 	uwb_dev_put(neighbor->uwb_dev);
 	list_del(&neighbor->node);
 	kfree(neighbor);
 }

 /**
  * Clear entire neighborhood cache.
  */
 static
 void __wlp_neighbors_release(struct wlp *wlp)
 {
 	struct wlp_neighbor_e *neighbor, *next;
 	if (list_empty(&wlp->neighbors))
 		return;
 	list_for_each_entry_safe(neighbor, next, &wlp->neighbors, node) {
 		__wlp_neighbor_release(neighbor);
 	}
 }

 static
 void wlp_neighbors_release(struct wlp *wlp)
 {
 	mutex_lock(&wlp->nbmutex);
 	__wlp_neighbors_release(wlp);
 	mutex_unlock(&wlp->nbmutex);
 }


 /**
  * Send D1 message to neighbor, receive D2 message
  *
  * @neighbor: neighbor to which D1 message will be sent
  * @wss:      if not NULL, it is an enrollment request for this WSS
  * @wssid:    if wss not NULL, this is the wssid of the WSS in which we
  *            want to enroll
  *
  * A D1/D2 exchange is done for one of two reasons: discovery or
  * enrollment. If done for discovery the D1 message is sent to the neighbor
  * and the contents of the D2 response is stored in a temporary cache.
  * If done for enrollment the @wss and @wssid are provided also. In this
  * case the D1 message is sent to the neighbor, the D2 response is parsed
  * for enrollment of the WSS with wssid.
  *
  * &wss->mutex is held
  */
 static
 int wlp_d1d2_exchange(struct wlp *wlp, struct wlp_neighbor_e *neighbor,
 		      struct wlp_wss *wss, struct wlp_uuid *wssid)
 {
 	int result;
 	struct device *dev = &wlp->rc->uwb_dev.dev;
 	DECLARE_COMPLETION_ONSTACK(completion);
 	struct wlp_session session;
 	struct sk_buff  *skb;
 	struct wlp_frame_assoc *resp;
 	struct uwb_dev_addr *dev_addr = &neighbor->uwb_dev->dev_addr;

 	mutex_lock(&wlp->mutex);
 	if (!wlp_uuid_is_set(&wlp->uuid)) {
 		dev_err(dev, "WLP: UUID is not set. Set via sysfs to "
 			"proceed.\n");
 		result = -ENXIO;
 		goto out;
 	}
 	/* Send D1 association frame */
 	result = wlp_send_assoc_frame(wlp, wss, dev_addr, WLP_ASSOC_D1);
 	if (result < 0) {
 		dev_err(dev, "Unable to send D1 frame to neighbor "
 			"%02x:%02x (%d)\n", dev_addr->data[1],
 			dev_addr->data[0], result);
 		goto out;
 	}
 	/* Create session, wait for response */
 	session.exp_message = WLP_ASSOC_D2;
 	session.cb = wlp_session_cb;
 	session.cb_priv = &completion;
 	session.neighbor_addr = *dev_addr;
 	BUG_ON(wlp->session != NULL);
 	wlp->session = &session;
 	/* Wait for D2/F0 frame */
 	result = wait_for_completion_interruptible_timeout(&completion,
 						   WLP_PER_MSG_TIMEOUT * HZ);
 	if (result == 0) {
 		result = -ETIMEDOUT;
 		dev_err(dev, "Timeout while sending D1 to neighbor "
 			     "%02x:%02x.\n", dev_addr->data[1],
 			     dev_addr->data[0]);
 		goto error_session;
 	}
 	if (result < 0) {
 		dev_err(dev, "Unable to discover/enroll neighbor %02x:%02x.\n",
 			dev_addr->data[1], dev_addr->data[0]);
 		goto error_session;
 	}
 	/* Parse message in session->data: it will be either D2 or F0 */
 	skb = session.data;
 	resp = (void *) skb->data;

 	if (resp->type == WLP_ASSOC_F0) {
 		result = wlp_parse_f0(wlp, skb);
 		if (result < 0)
 			dev_err(dev, "WLP: Unable to parse F0 from neighbor "
 				"%02x:%02x.\n", dev_addr->data[1],
 				dev_addr->data[0]);
 		result = -EINVAL;
 		goto error_resp_parse;
 	}
 	if (wss == NULL) {
 		/* Discovery */
 		result = wlp_parse_d2_frame_to_cache(wlp, skb, neighbor);
 		if (result < 0) {
 			dev_err(dev, "WLP: Unable to parse D2 message from "
 				"neighbor %02x:%02x for discovery.\n",
 				dev_addr->data[1], dev_addr->data[0]);
 			goto error_resp_parse;
 		}
 	} else {
 		/* Enrollment */
 		result = wlp_parse_d2_frame_to_enroll(wss, skb, neighbor,
 						      wssid);
 		if (result < 0) {
 			dev_err(dev, "WLP: Unable to parse D2 message from "
 				"neighbor %02x:%02x for enrollment.\n",
 				dev_addr->data[1], dev_addr->data[0]);
 			goto error_resp_parse;
 		}
 	}
 error_resp_parse:
 	kfree_skb(skb);
 error_session:
 	wlp->session = NULL;
 out:
 	mutex_unlock(&wlp->mutex);
 	return result;
 }

 /**
  * Enroll into WSS of provided WSSID by using neighbor as registrar
  *
  * &wss->mutex is held
  */
 int wlp_enroll_neighbor(struct wlp *wlp, struct wlp_neighbor_e *neighbor,
 			struct wlp_wss *wss, struct wlp_uuid *wssid)
 {
 	int result = 0;
 	struct device *dev = &wlp->rc->uwb_dev.dev;
 	char buf[WLP_WSS_UUID_STRSIZE];
 	struct uwb_dev_addr *dev_addr = &neighbor->uwb_dev->dev_addr;

 	wlp_wss_uuid_print(buf, sizeof(buf), wssid);

 	result =  wlp_d1d2_exchange(wlp, neighbor, wss, wssid);
 	if (result < 0) {
 		dev_err(dev, "WLP: D1/D2 message exchange for enrollment "
 			"failed. result = %d \n", result);
 		goto out;
 	}
 	if (wss->state != WLP_WSS_STATE_PART_ENROLLED) {
 		dev_err(dev, "WLP: Unable to enroll into WSS %s using "
 			"neighbor %02x:%02x. \n", buf,
 			dev_addr->data[1], dev_addr->data[0]);
 		result = -EINVAL;
 		goto out;
 	}
 	if (wss->secure_status == WLP_WSS_SECURE) {
 		dev_err(dev, "FIXME: need to complete secure enrollment.\n");
 		result = -EINVAL;
 		goto error;
 	} else {
 		wss->state = WLP_WSS_STATE_ENROLLED;
 		dev_dbg(dev, "WLP: Success Enrollment into unsecure WSS "
 			"%s using neighbor %02x:%02x. \n",
 			buf, dev_addr->data[1], dev_addr->data[0]);
 	}
 out:
 	return result;
 error:
 	wlp_wss_reset(wss);
 	return result;
 }

 /**
  * Discover WSS information of neighbor's active WSS
  */
 static
 int wlp_discover_neighbor(struct wlp *wlp,
 			  struct wlp_neighbor_e *neighbor)
 {
 	return wlp_d1d2_exchange(wlp, neighbor, NULL, NULL);
 }


 /**
  * Each neighbor in the neighborhood cache is discoverable. Discover it.
  *
  * Discovery is done through sending of D1 association frame and parsing
  * the D2 association frame response. Only wssid from D2 will be included
  * in neighbor cache, rest is just displayed to user and forgotten.
  *
  * The discovery is not done in parallel. This is simple and enables us to
  * maintain only one association context.
  *
  * The discovery of one neighbor does not affect the other, but if the
  * discovery of a neighbor fails it is removed from the neighborhood cache.
  */
 static
 int wlp_discover_all_neighbors(struct wlp *wlp)
 {
 	int result = 0;
 	struct device *dev = &wlp->rc->uwb_dev.dev;
 	struct wlp_neighbor_e *neighbor, *next;

 	list_for_each_entry_safe(neighbor, next, &wlp->neighbors, node) {
 		result = wlp_discover_neighbor(wlp, neighbor);
 		if (result < 0) {
 			dev_err(dev, "WLP: Unable to discover neighbor "
 				"%02x:%02x, removing from neighborhood. \n",
 				neighbor->uwb_dev->dev_addr.data[1],
 				neighbor->uwb_dev->dev_addr.data[0]);
 			__wlp_neighbor_release(neighbor);
 		}
 	}
 	return result;
 }

 static int wlp_add_neighbor_helper(struct device *dev, void *priv)
 {
 	struct wlp *wlp = priv;
 	struct uwb_dev *uwb_dev = to_uwb_dev(dev);

 	return wlp_add_neighbor(wlp, uwb_dev);
 }

 /**
  * Discover WLP neighborhood
  *
  * Will send D1 association frame to all devices in beacon group that have
  * discoverable bit set in WLP IE. D2 frames will be received, information
  * displayed to user in @buf. Partial information (from D2 association
  * frame) will be cached to assist with future association
  * requests.
  *
  * The discovery of the WLP neighborhood is triggered by the user. This
  * should occur infrequently and we thus free current cache and re-allocate
  * memory if needed.
  *
  * If one neighbor fails during initial discovery (determining if it is a
  * neighbor or not), we fail all - note that interaction with neighbor has
  * not occured at this point so if a failure occurs we know something went wrong
  * locally. We thus undo everything.
  */
 ssize_t wlp_discover(struct wlp *wlp)
 {
 	int result = 0;
 	struct device *dev = &wlp->rc->uwb_dev.dev;

 	mutex_lock(&wlp->nbmutex);
 	/* Clear current neighborhood cache. */
 	__wlp_neighbors_release(wlp);
 	/* Determine which devices in neighborhood. Repopulate cache. */
 	result = uwb_dev_for_each(wlp->rc, wlp_add_neighbor_helper, wlp);
 	if (result < 0) {
 		/* May have partial neighbor information, release all. */
 		__wlp_neighbors_release(wlp);
 		goto error_dev_for_each;
 	}
 	/* Discover the properties of devices in neighborhood. */
 	result = wlp_discover_all_neighbors(wlp);
 	/* In case of failure we still print our partial results. */
 	if (result < 0) {
 		dev_err(dev, "Unable to fully discover neighborhood. \n");
 		result = 0;
 	}
 error_dev_for_each:
 	mutex_unlock(&wlp->nbmutex);
 	return result;
 }

 /**
  * Handle events from UWB stack
  *
  * We handle events conservatively. If a neighbor goes off the air we
  * remove it from the neighborhood. If an association process is in
  * progress this function will block waiting for the nbmutex to become
  * free. The association process will thus be allowed to complete before it
  * is removed.
  */
 static
 void wlp_uwb_notifs_cb(void *_wlp, struct uwb_dev *uwb_dev,
 		       enum uwb_notifs event)
 {
 	struct wlp *wlp = _wlp;
 	struct device *dev = &wlp->rc->uwb_dev.dev;
 	struct wlp_neighbor_e *neighbor, *next;
 	int result;
 	switch (event) {
 	case UWB_NOTIF_ONAIR:
 		result = wlp_eda_create_node(&wlp->eda,
 					     uwb_dev->mac_addr.data,
 					     &uwb_dev->dev_addr);
 		if (result < 0)
 			dev_err(dev, "WLP: Unable to add new neighbor "
 				"%02x:%02x to EDA cache.\n",
 				uwb_dev->dev_addr.data[1],
 				uwb_dev->dev_addr.data[0]);
 		break;
 	case UWB_NOTIF_OFFAIR:
 		wlp_eda_rm_node(&wlp->eda, &uwb_dev->dev_addr);
 		mutex_lock(&wlp->nbmutex);
 		list_for_each_entry_safe(neighbor, next, &wlp->neighbors, node) {
 			if (neighbor->uwb_dev == uwb_dev)
 				__wlp_neighbor_release(neighbor);
 		}
 		mutex_unlock(&wlp->nbmutex);
 		break;
 	default:
 		dev_err(dev, "don't know how to handle event %d from uwb\n",
 				event);
 	}
 }

 static void wlp_channel_changed(struct uwb_pal *pal, int channel)
 {
 	struct wlp *wlp = container_of(pal, struct wlp, pal);

 	if (channel < 0)
 		netif_carrier_off(wlp->ndev);
 	else
 		netif_carrier_on(wlp->ndev);
 }

 int wlp_setup(struct wlp *wlp, struct uwb_rc *rc, struct net_device *ndev)
 {
 	int result;

 	BUG_ON(wlp->fill_device_info == NULL);
 	BUG_ON(wlp->xmit_frame == NULL);
 	BUG_ON(wlp->stop_queue == NULL);
 	BUG_ON(wlp->start_queue == NULL);

 	wlp->rc = rc;
 	wlp->ndev = ndev;
 	wlp_eda_init(&wlp->eda);/* Set up address cache */
 	wlp->uwb_notifs_handler.cb = wlp_uwb_notifs_cb;
 	wlp->uwb_notifs_handler.data = wlp;
 	uwb_notifs_register(rc, &wlp->uwb_notifs_handler);

 	uwb_pal_init(&wlp->pal);
 	wlp->pal.rc = rc;
 	wlp->pal.channel_changed = wlp_channel_changed;
 	result = uwb_pal_register(&wlp->pal);
 	if (result < 0)
 		uwb_notifs_deregister(wlp->rc, &wlp->uwb_notifs_handler);

 	return result;
 }
 EXPORT_SYMBOL_GPL(wlp_setup);

 void wlp_remove(struct wlp *wlp)
 {
 	wlp_neighbors_release(wlp);
 	uwb_pal_unregister(&wlp->pal);
 	uwb_notifs_deregister(wlp->rc, &wlp->uwb_notifs_handler);
 	wlp_eda_release(&wlp->eda);
 	mutex_lock(&wlp->mutex);
 	if (wlp->dev_info != NULL)
 		kfree(wlp->dev_info);
 	mutex_unlock(&wlp->mutex);
 	wlp->rc = NULL;
 }
 EXPORT_SYMBOL_GPL(wlp_remove);

 /**
  * wlp_reset_all - reset the WLP hardware
  * @wlp: the WLP device to reset.
  *
  * This schedules a full hardware reset of the WLP device.  The radio
  * controller and any other PALs will also be reset.
  */
 void wlp_reset_all(struct wlp *wlp)
 {
 	uwb_rc_reset_all(wlp->rc);
 }
 EXPORT_SYMBOL_GPL(wlp_reset_all);
	/*
	* WiMedia Logical Link Control Protocol (WLP)
	*
	* Copyright (C) 2005-2006 Intel Corporation
	* Reinette Chatre <reinette.chatre@intel.com>
	*
	* 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.
	*
	* 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., 51 Franklin Street, Fifth Floor, Boston, MA
	* 02110-1301, USA.
	*
	*
	* FIXME: docs
	*/
	#include <linux/wlp.h>

	#include "wlp-internal.h"

	static
	void wlp_neighbor_init(struct wlp_neighbor_e *neighbor)
	{
	INIT_LIST_HEAD(&neighbor->wssid);
	}

	/**
	* Create area for device information storage
	*
	* wlp->mutex must be held
	*/
	int __wlp_alloc_device_info(struct wlp *wlp)
	{
	struct device *dev = &wlp->rc->uwb_dev.dev;
	BUG_ON(wlp->dev_info != NULL);
	wlp->dev_info = kzalloc(sizeof(struct wlp_device_info), GFP_KERNEL);
	if (wlp->dev_info == NULL) {
	dev_err(dev, "WLP: Unable to allocate memory for "
	"device information.\n");
	return -ENOMEM;
	}
	return 0;
	}


	/**
	* Fill in device information using function provided by driver
	*
	* wlp->mutex must be held
	*/
	static
	void __wlp_fill_device_info(struct wlp *wlp)
	{
	wlp->fill_device_info(wlp, wlp->dev_info);
	}

	/**
	* Setup device information
	*
	* Allocate area for device information and populate it.
	*
	* wlp->mutex must be held
	*/
	int __wlp_setup_device_info(struct wlp *wlp)
	{
	int result;
	struct device *dev = &wlp->rc->uwb_dev.dev;

	result = __wlp_alloc_device_info(wlp);
	if (result < 0) {
	dev_err(dev, "WLP: Unable to allocate area for "
	"device information.\n");
	return result;
	}
	__wlp_fill_device_info(wlp);
	return 0;
	}

	/**
	* Remove information about neighbor stored temporarily
	*
	* Information learned during discovey should only be stored when the
	* device enrolls in the neighbor's WSS. We do need to store this
	* information temporarily in order to present it to the user.
	*
	* We are only interested in keeping neighbor WSS information if that
	* neighbor is accepting enrollment.
	*
	* should be called with wlp->nbmutex held
	*/
	void wlp_remove_neighbor_tmp_info(struct wlp_neighbor_e *neighbor)
	{
	struct wlp_wssid_e wssid_e, next;
	u8 keep;
	if (!list_empty(&neighbor->wssid)) {
	list_for_each_entry_safe(wssid_e, next, &neighbor->wssid,
	node) {
	if (wssid_e->info != NULL) {
	keep = wssid_e->info->accept_enroll;
	kfree(wssid_e->info);
	wssid_e->info = NULL;
	if (!keep) {
	list_del(&wssid_e->node);
	kfree(wssid_e);
	}
	}
	}
	}
	if (neighbor->info != NULL) {
	kfree(neighbor->info);
	neighbor->info = NULL;
	}
	}

	/*
	* Populate WLP neighborhood cache with neighbor information
	*
	* A new neighbor is found. If it is discoverable then we add it to the
	* neighborhood cache.
	*
	*/
	static
	int wlp_add_neighbor(struct wlp wlp, struct uwb_dev dev)
	{
	int result = 0;
	int discoverable;
	struct wlp_neighbor_e *neighbor;

	/*
	* FIXME:
	* Use contents of WLP IE found in beacon cache to determine if
	* neighbor is discoverable.
	* The device does not support WLP IE yet so this still needs to be
	* done. Until then we assume all devices are discoverable.
	*/
	discoverable = 1; /* will be changed when FIXME disappears */
	if (discoverable) {
	/* Add neighbor to cache for discovery */
	neighbor = kzalloc(sizeof(*neighbor), GFP_KERNEL);
	if (neighbor == NULL) {
	dev_err(&dev->dev, "Unable to create memory for "
	"new neighbor. \n");
	result = -ENOMEM;
	goto error_no_mem;
	}
	wlp_neighbor_init(neighbor);
	uwb_dev_get(dev);
	neighbor->uwb_dev = dev;
	list_add(&neighbor->node, &wlp->neighbors);
	}
	error_no_mem:
	return result;
	}

	/**
	* Remove one neighbor from cache
	*/
	static
	void __wlp_neighbor_release(struct wlp_neighbor_e *neighbor)
	{
	struct wlp_wssid_e wssid_e, next_wssid_e;

	list_for_each_entry_safe(wssid_e, next_wssid_e,
	&neighbor->wssid, node) {
	list_del(&wssid_e->node);
	kfree(wssid_e);
	}
	uwb_dev_put(neighbor->uwb_dev);
	list_del(&neighbor->node);
	kfree(neighbor);
	}

	/**
	* Clear entire neighborhood cache.
	*/
	static
	void __wlp_neighbors_release(struct wlp *wlp)
	{
	struct wlp_neighbor_e neighbor, next;
	if (list_empty(&wlp->neighbors))
	return;
	list_for_each_entry_safe(neighbor, next, &wlp->neighbors, node) {
	__wlp_neighbor_release(neighbor);
	}
	}

	static
	void wlp_neighbors_release(struct wlp *wlp)
	{
	mutex_lock(&wlp->nbmutex);
	__wlp_neighbors_release(wlp);
	mutex_unlock(&wlp->nbmutex);
	}



	/**
	* Send D1 message to neighbor, receive D2 message
	*
	* @neighbor: neighbor to which D1 message will be sent
	* @wss: if not NULL, it is an enrollment request for this WSS
	* @wssid: if wss not NULL, this is the wssid of the WSS in which we
	* want to enroll
	*
	* A D1/D2 exchange is done for one of two reasons: discovery or
	* enrollment. If done for discovery the D1 message is sent to the neighbor
	* and the contents of the D2 response is stored in a temporary cache.
	* If done for enrollment the @wss and @wssid are provided also. In this
	* case the D1 message is sent to the neighbor, the D2 response is parsed
	* for enrollment of the WSS with wssid.
	*
	* &wss->mutex is held
	*/
	static
	int wlp_d1d2_exchange(struct wlp wlp, struct wlp_neighbor_e neighbor,
	struct wlp_wss wss, struct wlp_uuid wssid)
	{
	int result;
	struct device *dev = &wlp->rc->uwb_dev.dev;
	DECLARE_COMPLETION_ONSTACK(completion);
	struct wlp_session session;
	struct sk_buff *skb;
	struct wlp_frame_assoc *resp;
	struct uwb_dev_addr *dev_addr = &neighbor->uwb_dev->dev_addr;

	mutex_lock(&wlp->mutex);
	if (!wlp_uuid_is_set(&wlp->uuid)) {
	dev_err(dev, "WLP: UUID is not set. Set via sysfs to "
	"proceed.\n");
	result = -ENXIO;
	goto out;
	}
	/* Send D1 association frame */
	result = wlp_send_assoc_frame(wlp, wss, dev_addr, WLP_ASSOC_D1);
	if (result < 0) {
	dev_err(dev, "Unable to send D1 frame to neighbor "
	"%02x:%02x (%d)\n", dev_addr->data[1],
	dev_addr->data[0], result);
	goto out;
	}
	/* Create session, wait for response */
	session.exp_message = WLP_ASSOC_D2;
	session.cb = wlp_session_cb;
	session.cb_priv = &completion;
	session.neighbor_addr = *dev_addr;
	BUG_ON(wlp->session != NULL);
	wlp->session = &session;
	/* Wait for D2/F0 frame */
	result = wait_for_completion_interruptible_timeout(&completion,
	WLP_PER_MSG_TIMEOUT * HZ);
	if (result == 0) {
	result = -ETIMEDOUT;
	dev_err(dev, "Timeout while sending D1 to neighbor "
	"%02x:%02x.\n", dev_addr->data[1],
	dev_addr->data[0]);
	goto error_session;
	}
	if (result < 0) {
	dev_err(dev, "Unable to discover/enroll neighbor %02x:%02x.\n",
	dev_addr->data[1], dev_addr->data[0]);
	goto error_session;
	}
	/* Parse message in session->data: it will be either D2 or F0 */
	skb = session.data;
	resp = (void *) skb->data;

	if (resp->type == WLP_ASSOC_F0) {
	result = wlp_parse_f0(wlp, skb);
	if (result < 0)
	dev_err(dev, "WLP: Unable to parse F0 from neighbor "
	"%02x:%02x.\n", dev_addr->data[1],
	dev_addr->data[0]);
	result = -EINVAL;
	goto error_resp_parse;
	}
	if (wss == NULL) {
	/* Discovery */
	result = wlp_parse_d2_frame_to_cache(wlp, skb, neighbor);
	if (result < 0) {
	dev_err(dev, "WLP: Unable to parse D2 message from "
	"neighbor %02x:%02x for discovery.\n",
	dev_addr->data[1], dev_addr->data[0]);
	goto error_resp_parse;
	}
	} else {
	/* Enrollment */
	result = wlp_parse_d2_frame_to_enroll(wss, skb, neighbor,
	wssid);
	if (result < 0) {
	dev_err(dev, "WLP: Unable to parse D2 message from "
	"neighbor %02x:%02x for enrollment.\n",
	dev_addr->data[1], dev_addr->data[0]);
	goto error_resp_parse;
	}
	}
	error_resp_parse:
	kfree_skb(skb);
	error_session:
	wlp->session = NULL;
	out:
	mutex_unlock(&wlp->mutex);
	return result;
	}

	/**
	* Enroll into WSS of provided WSSID by using neighbor as registrar
	*
	* &wss->mutex is held
	*/
	int wlp_enroll_neighbor(struct wlp wlp, struct wlp_neighbor_e neighbor,
	struct wlp_wss wss, struct wlp_uuid wssid)
	{
	int result = 0;
	struct device *dev = &wlp->rc->uwb_dev.dev;
	char buf[WLP_WSS_UUID_STRSIZE];
	struct uwb_dev_addr *dev_addr = &neighbor->uwb_dev->dev_addr;

	wlp_wss_uuid_print(buf, sizeof(buf), wssid);

	result = wlp_d1d2_exchange(wlp, neighbor, wss, wssid);
	if (result < 0) {
	dev_err(dev, "WLP: D1/D2 message exchange for enrollment "
	"failed. result = %d \n", result);
	goto out;
	}
	if (wss->state != WLP_WSS_STATE_PART_ENROLLED) {
	dev_err(dev, "WLP: Unable to enroll into WSS %s using "
	"neighbor %02x:%02x. \n", buf,
	dev_addr->data[1], dev_addr->data[0]);
	result = -EINVAL;
	goto out;
	}
	if (wss->secure_status == WLP_WSS_SECURE) {
	dev_err(dev, "FIXME: need to complete secure enrollment.\n");
	result = -EINVAL;
	goto error;
	} else {
	wss->state = WLP_WSS_STATE_ENROLLED;
	dev_dbg(dev, "WLP: Success Enrollment into unsecure WSS "
	"%s using neighbor %02x:%02x. \n",
	buf, dev_addr->data[1], dev_addr->data[0]);
	}
	out:
	return result;
	error:
	wlp_wss_reset(wss);
	return result;
	}

	/**
	* Discover WSS information of neighbor's active WSS
	*/
	static
	int wlp_discover_neighbor(struct wlp *wlp,
	struct wlp_neighbor_e *neighbor)
	{
	return wlp_d1d2_exchange(wlp, neighbor, NULL, NULL);
	}


	/**
	* Each neighbor in the neighborhood cache is discoverable. Discover it.
	*
	* Discovery is done through sending of D1 association frame and parsing
	* the D2 association frame response. Only wssid from D2 will be included
	* in neighbor cache, rest is just displayed to user and forgotten.
	*
	* The discovery is not done in parallel. This is simple and enables us to
	* maintain only one association context.
	*
	* The discovery of one neighbor does not affect the other, but if the
	* discovery of a neighbor fails it is removed from the neighborhood cache.
	*/
	static
	int wlp_discover_all_neighbors(struct wlp *wlp)
	{
	int result = 0;
	struct device *dev = &wlp->rc->uwb_dev.dev;
	struct wlp_neighbor_e neighbor, next;

	list_for_each_entry_safe(neighbor, next, &wlp->neighbors, node) {
	result = wlp_discover_neighbor(wlp, neighbor);
	if (result < 0) {
	dev_err(dev, "WLP: Unable to discover neighbor "
	"%02x:%02x, removing from neighborhood. \n",
	neighbor->uwb_dev->dev_addr.data[1],
	neighbor->uwb_dev->dev_addr.data[0]);
	__wlp_neighbor_release(neighbor);
	}
	}
	return result;
	}

	static int wlp_add_neighbor_helper(struct device dev, void priv)
	{
	struct wlp *wlp = priv;
	struct uwb_dev *uwb_dev = to_uwb_dev(dev);

	return wlp_add_neighbor(wlp, uwb_dev);
	}

	/**
	* Discover WLP neighborhood
	*
	* Will send D1 association frame to all devices in beacon group that have
	* discoverable bit set in WLP IE. D2 frames will be received, information
	* displayed to user in @buf. Partial information (from D2 association
	* frame) will be cached to assist with future association
	* requests.
	*
	* The discovery of the WLP neighborhood is triggered by the user. This
	* should occur infrequently and we thus free current cache and re-allocate
	* memory if needed.
	*
	* If one neighbor fails during initial discovery (determining if it is a
	* neighbor or not), we fail all - note that interaction with neighbor has
	* not occured at this point so if a failure occurs we know something went wrong
	* locally. We thus undo everything.
	*/
	ssize_t wlp_discover(struct wlp *wlp)
	{
	int result = 0;
	struct device *dev = &wlp->rc->uwb_dev.dev;

	mutex_lock(&wlp->nbmutex);
	/* Clear current neighborhood cache. */
	__wlp_neighbors_release(wlp);
	/* Determine which devices in neighborhood. Repopulate cache. */
	result = uwb_dev_for_each(wlp->rc, wlp_add_neighbor_helper, wlp);
	if (result < 0) {
	/* May have partial neighbor information, release all. */
	__wlp_neighbors_release(wlp);
	goto error_dev_for_each;
	}
	/* Discover the properties of devices in neighborhood. */
	result = wlp_discover_all_neighbors(wlp);
	/* In case of failure we still print our partial results. */
	if (result < 0) {
	dev_err(dev, "Unable to fully discover neighborhood. \n");
	result = 0;
	}
	error_dev_for_each:
	mutex_unlock(&wlp->nbmutex);
	return result;
	}

	/**
	* Handle events from UWB stack
	*
	* We handle events conservatively. If a neighbor goes off the air we
	* remove it from the neighborhood. If an association process is in
	* progress this function will block waiting for the nbmutex to become
	* free. The association process will thus be allowed to complete before it
	* is removed.
	*/
	static
	void wlp_uwb_notifs_cb(void _wlp, struct uwb_dev uwb_dev,
	enum uwb_notifs event)
	{
	struct wlp *wlp = _wlp;
	struct device *dev = &wlp->rc->uwb_dev.dev;
	struct wlp_neighbor_e neighbor, next;
	int result;
	switch (event) {
	case UWB_NOTIF_ONAIR:
	result = wlp_eda_create_node(&wlp->eda,
	uwb_dev->mac_addr.data,
	&uwb_dev->dev_addr);
	if (result < 0)
	dev_err(dev, "WLP: Unable to add new neighbor "
	"%02x:%02x to EDA cache.\n",
	uwb_dev->dev_addr.data[1],
	uwb_dev->dev_addr.data[0]);
	break;
	case UWB_NOTIF_OFFAIR:
	wlp_eda_rm_node(&wlp->eda, &uwb_dev->dev_addr);
	mutex_lock(&wlp->nbmutex);
	list_for_each_entry_safe(neighbor, next, &wlp->neighbors, node) {
	if (neighbor->uwb_dev == uwb_dev)
	__wlp_neighbor_release(neighbor);
	}
	mutex_unlock(&wlp->nbmutex);
	break;
	default:
	dev_err(dev, "don't know how to handle event %d from uwb\n",
	event);
	}
	}

	static void wlp_channel_changed(struct uwb_pal *pal, int channel)
	{
	struct wlp *wlp = container_of(pal, struct wlp, pal);

	if (channel < 0)
	netif_carrier_off(wlp->ndev);
	else
	netif_carrier_on(wlp->ndev);
	}

	int wlp_setup(struct wlp wlp, struct uwb_rc rc, struct net_device *ndev)
	{
	int result;

	BUG_ON(wlp->fill_device_info == NULL);
	BUG_ON(wlp->xmit_frame == NULL);
	BUG_ON(wlp->stop_queue == NULL);
	BUG_ON(wlp->start_queue == NULL);

	wlp->rc = rc;
	wlp->ndev = ndev;
	wlp_eda_init(&wlp->eda);/* Set up address cache */
	wlp->uwb_notifs_handler.cb = wlp_uwb_notifs_cb;
	wlp->uwb_notifs_handler.data = wlp;
	uwb_notifs_register(rc, &wlp->uwb_notifs_handler);

	uwb_pal_init(&wlp->pal);
	wlp->pal.rc = rc;
	wlp->pal.channel_changed = wlp_channel_changed;
	result = uwb_pal_register(&wlp->pal);
	if (result < 0)
	uwb_notifs_deregister(wlp->rc, &wlp->uwb_notifs_handler);

	return result;
	}
	EXPORT_SYMBOL_GPL(wlp_setup);

	void wlp_remove(struct wlp *wlp)
	{
	wlp_neighbors_release(wlp);
	uwb_pal_unregister(&wlp->pal);
	uwb_notifs_deregister(wlp->rc, &wlp->uwb_notifs_handler);
	wlp_eda_release(&wlp->eda);
	mutex_lock(&wlp->mutex);
	if (wlp->dev_info != NULL)
	kfree(wlp->dev_info);
	mutex_unlock(&wlp->mutex);
	wlp->rc = NULL;
	}
	EXPORT_SYMBOL_GPL(wlp_remove);

	/**
	* wlp_reset_all - reset the WLP hardware
	* @wlp: the WLP device to reset.
	*
	* This schedules a full hardware reset of the WLP device. The radio
	* controller and any other PALs will also be reset.
	*/
	void wlp_reset_all(struct wlp *wlp)
	{
	uwb_rc_reset_all(wlp->rc);
	}
	EXPORT_SYMBOL_GPL(wlp_reset_all);