uwb: add the UWB stack (reservation manager)

DRP and reservation management.

Signed-off-by: David Vrabel <david.vrabel@csr.com>

1 files changed, 680 insertions, 0 deletions

diff --git a/drivers/uwb/rsv.c b/drivers/uwb/rsv.c
new file mode 100644
index 00000000000..bae16204576
--- /dev/null
+++ b/drivers/uwb/rsv.c
@@ -0,0 +1,680 @@
+/*
+ * UWB reservation management.
+ *
+ * Copyright (C) 2008 Cambridge Silicon Radio Ltd.
+ *
+ * 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, see <http://www.gnu.org/licenses/>.
+ */
+#include <linux/version.h>
+#include <linux/kernel.h>
+#include <linux/uwb.h>
+
+#include "uwb-internal.h"
+
+static void uwb_rsv_timer(unsigned long arg);
+
+static const char *rsv_states[] = {
+	[UWB_RSV_STATE_NONE]          = "none",
+	[UWB_RSV_STATE_O_INITIATED]   = "initiated",
+	[UWB_RSV_STATE_O_PENDING]     = "pending",
+	[UWB_RSV_STATE_O_MODIFIED]    = "modified",
+	[UWB_RSV_STATE_O_ESTABLISHED] = "established",
+	[UWB_RSV_STATE_T_ACCEPTED]    = "accepted",
+	[UWB_RSV_STATE_T_DENIED]      = "denied",
+	[UWB_RSV_STATE_T_PENDING]     = "pending",
+};
+
+static const char *rsv_types[] = {
+	[UWB_DRP_TYPE_ALIEN_BP] = "alien-bp",
+	[UWB_DRP_TYPE_HARD]     = "hard",
+	[UWB_DRP_TYPE_SOFT]     = "soft",
+	[UWB_DRP_TYPE_PRIVATE]  = "private",
+	[UWB_DRP_TYPE_PCA]      = "pca",
+};
+
+/**
+ * uwb_rsv_state_str - return a string for a reservation state
+ * @state: the reservation state.
+ */
+const char *uwb_rsv_state_str(enum uwb_rsv_state state)
+{
+	if (state < UWB_RSV_STATE_NONE || state >= UWB_RSV_STATE_LAST)
+		return "unknown";
+	return rsv_states[state];
+}
+EXPORT_SYMBOL_GPL(uwb_rsv_state_str);
+
+/**
+ * uwb_rsv_type_str - return a string for a reservation type
+ * @type: the reservation type
+ */
+const char *uwb_rsv_type_str(enum uwb_drp_type type)
+{
+	if (type < UWB_DRP_TYPE_ALIEN_BP || type > UWB_DRP_TYPE_PCA)
+		return "invalid";
+	return rsv_types[type];
+}
+EXPORT_SYMBOL_GPL(uwb_rsv_type_str);
+
+static void uwb_rsv_dump(struct uwb_rsv *rsv)
+{
+	struct device *dev = &rsv->rc->uwb_dev.dev;
+	struct uwb_dev_addr devaddr;
+	char owner[UWB_ADDR_STRSIZE], target[UWB_ADDR_STRSIZE];
+
+	uwb_dev_addr_print(owner, sizeof(owner), &rsv->owner->dev_addr);
+	if (rsv->target.type == UWB_RSV_TARGET_DEV)
+		devaddr = rsv->target.dev->dev_addr;
+	else
+		devaddr = rsv->target.devaddr;
+	uwb_dev_addr_print(target, sizeof(target), &devaddr);
+
+	dev_dbg(dev, "rsv %s -> %s: %s\n", owner, target, uwb_rsv_state_str(rsv->state));
+}
+
+/*
+ * Get a free stream index for a reservation.
+ *
+ * If the target is a DevAddr (e.g., a WUSB cluster reservation) then
+ * the stream is allocated from a pool of per-RC stream indexes,
+ * otherwise a unique stream index for the target is selected.
+ */
+static int uwb_rsv_get_stream(struct uwb_rsv *rsv)
+{
+	struct uwb_rc *rc = rsv->rc;
+	unsigned long *streams_bm;
+	int stream;
+
+	switch (rsv->target.type) {
+	case UWB_RSV_TARGET_DEV:
+		streams_bm = rsv->target.dev->streams;
+		break;
+	case UWB_RSV_TARGET_DEVADDR:
+		streams_bm = rc->uwb_dev.streams;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	stream = find_first_zero_bit(streams_bm, UWB_NUM_STREAMS);
+	if (stream >= UWB_NUM_STREAMS)
+		return -EBUSY;
+
+	rsv->stream = stream;
+	set_bit(stream, streams_bm);
+
+	return 0;
+}
+
+static void uwb_rsv_put_stream(struct uwb_rsv *rsv)
+{
+	struct uwb_rc *rc = rsv->rc;
+	unsigned long *streams_bm;
+
+	switch (rsv->target.type) {
+	case UWB_RSV_TARGET_DEV:
+		streams_bm = rsv->target.dev->streams;
+		break;
+	case UWB_RSV_TARGET_DEVADDR:
+		streams_bm = rc->uwb_dev.streams;
+		break;
+	default:
+		return;
+	}
+
+	clear_bit(rsv->stream, streams_bm);
+}
+
+/*
+ * Generate a MAS allocation with a single row component.
+ */
+static void uwb_rsv_gen_alloc_row(struct uwb_mas_bm *mas,
+				  int first_mas, int mas_per_zone,
+				  int zs, int ze)
+{
+	struct uwb_mas_bm col;
+	int z;
+
+	bitmap_zero(mas->bm, UWB_NUM_MAS);
+	bitmap_zero(col.bm, UWB_NUM_MAS);
+	bitmap_fill(col.bm, mas_per_zone);
+	bitmap_shift_left(col.bm, col.bm, first_mas + zs * UWB_MAS_PER_ZONE, UWB_NUM_MAS);
+
+	for (z = zs; z <= ze; z++) {
+		bitmap_or(mas->bm, mas->bm, col.bm, UWB_NUM_MAS);
+		bitmap_shift_left(col.bm, col.bm, UWB_MAS_PER_ZONE, UWB_NUM_MAS);
+	}
+}
+
+/*
+ * Allocate some MAS for this reservation based on current local
+ * availability, the reservation parameters (max_mas, min_mas,
+ * sparsity), and the WiMedia rules for MAS allocations.
+ *
+ * Returns -EBUSY is insufficient free MAS are available.
+ *
+ * FIXME: to simplify this, only safe reservations with a single row
+ * component in zones 1 to 15 are tried (zone 0 is skipped to avoid
+ * problems with the MAS reserved for the BP).
+ *
+ * [ECMA-368] section B.2.
+ */
+static int uwb_rsv_alloc_mas(struct uwb_rsv *rsv)
+{
+	static const int safe_mas_in_row[UWB_NUM_ZONES] = {
+		8, 7, 6, 5, 4, 4, 4, 4, 4, 4, 4, 4, 4, 3, 2, 1,
+	};
+	int n, r;
+	struct uwb_mas_bm mas;
+	bool found = false;
+
+	/*
+	 * Search all valid safe allocations until either: too few MAS
+	 * are available; or the smallest allocation with sufficient
+	 * MAS is found.
+	 *
+	 * The top of the zones are preferred, so space for larger
+	 * allocations is available in the bottom of the zone (e.g., a
+	 * 15 MAS allocation should start in row 14 leaving space for
+	 * a 120 MAS allocation at row 0).
+	 */
+	for (n = safe_mas_in_row[0]; n >= 1; n--) {
+		int num_mas;
+
+		num_mas = n * (UWB_NUM_ZONES - 1);
+		if (num_mas < rsv->min_mas)
+			break;
+		if (found && num_mas < rsv->max_mas)
+			break;
+
+		for (r = UWB_MAS_PER_ZONE-1;  r >= 0; r--) {
+			if (safe_mas_in_row[r] < n)
+				continue;
+			uwb_rsv_gen_alloc_row(&mas, r, n, 1, UWB_NUM_ZONES);
+			if (uwb_drp_avail_reserve_pending(rsv->rc, &mas) == 0) {
+				found = true;
+				break;
+			}
+		}
+	}
+
+	if (!found)
+		return -EBUSY;
+
+	bitmap_copy(rsv->mas.bm, mas.bm, UWB_NUM_MAS);
+	return 0;
+}
+
+static void uwb_rsv_stroke_timer(struct uwb_rsv *rsv)
+{
+	int sframes = UWB_MAX_LOST_BEACONS;
+
+	/*
+	 * Multicast reservations can become established within 1
+	 * super frame and should not be terminated if no response is
+	 * received.
+	 */
+	if (rsv->is_multicast) {
+		if (rsv->state == UWB_RSV_STATE_O_INITIATED)
+			sframes = 1;
+		if (rsv->state == UWB_RSV_STATE_O_ESTABLISHED)
+			sframes = 0;
+	}
+
+	rsv->expired = false;
+	if (sframes > 0) {
+		/*
+		 * Add an additional 2 superframes to account for the
+		 * time to send the SET DRP IE command.
+		 */
+		unsigned timeout_us = (sframes + 2) * UWB_SUPERFRAME_LENGTH_US;
+		mod_timer(&rsv->timer, jiffies + usecs_to_jiffies(timeout_us));
+	} else
+		del_timer(&rsv->timer);
+}
+
+/*
+ * Update a reservations state, and schedule an update of the
+ * transmitted DRP IEs.
+ */
+static void uwb_rsv_state_update(struct uwb_rsv *rsv,
+				 enum uwb_rsv_state new_state)
+{
+	rsv->state = new_state;
+	rsv->ie_valid = false;
+
+	uwb_rsv_dump(rsv);
+
+	uwb_rsv_stroke_timer(rsv);
+	uwb_rsv_sched_update(rsv->rc);
+}
+
+static void uwb_rsv_callback(struct uwb_rsv *rsv)
+{
+	if (rsv->callback)
+		rsv->callback(rsv);
+}
+
+void uwb_rsv_set_state(struct uwb_rsv *rsv, enum uwb_rsv_state new_state)
+{
+	if (rsv->state == new_state) {
+		switch (rsv->state) {
+		case UWB_RSV_STATE_O_ESTABLISHED:
+		case UWB_RSV_STATE_T_ACCEPTED:
+		case UWB_RSV_STATE_NONE:
+			uwb_rsv_stroke_timer(rsv);
+			break;
+		default:
+			/* Expecting a state transition so leave timer
+			   as-is. */
+			break;
+		}
+		return;
+	}
+
+	switch (new_state) {
+	case UWB_RSV_STATE_NONE:
+		uwb_drp_avail_release(rsv->rc, &rsv->mas);
+		uwb_rsv_put_stream(rsv);
+		uwb_rsv_state_update(rsv, UWB_RSV_STATE_NONE);
+		uwb_rsv_callback(rsv);
+		break;
+	case UWB_RSV_STATE_O_INITIATED:
+		uwb_rsv_state_update(rsv, UWB_RSV_STATE_O_INITIATED);
+		break;
+	case UWB_RSV_STATE_O_PENDING:
+		uwb_rsv_state_update(rsv, UWB_RSV_STATE_O_PENDING);
+		break;
+	case UWB_RSV_STATE_O_ESTABLISHED:
+		uwb_drp_avail_reserve(rsv->rc, &rsv->mas);
+		uwb_rsv_state_update(rsv, UWB_RSV_STATE_O_ESTABLISHED);
+		uwb_rsv_callback(rsv);
+		break;
+	case UWB_RSV_STATE_T_ACCEPTED:
+		uwb_drp_avail_reserve(rsv->rc, &rsv->mas);
+		uwb_rsv_state_update(rsv, UWB_RSV_STATE_T_ACCEPTED);
+		uwb_rsv_callback(rsv);
+		break;
+	case UWB_RSV_STATE_T_DENIED:
+		uwb_rsv_state_update(rsv, UWB_RSV_STATE_T_DENIED);
+		break;
+	default:
+		dev_err(&rsv->rc->uwb_dev.dev, "unhandled state: %s (%d)\n",
+			uwb_rsv_state_str(new_state), new_state);
+	}
+}
+
+static struct uwb_rsv *uwb_rsv_alloc(struct uwb_rc *rc)
+{
+	struct uwb_rsv *rsv;
+
+	rsv = kzalloc(sizeof(struct uwb_rsv), GFP_KERNEL);
+	if (!rsv)
+		return NULL;
+
+	INIT_LIST_HEAD(&rsv->rc_node);
+	INIT_LIST_HEAD(&rsv->pal_node);
+	init_timer(&rsv->timer);
+	rsv->timer.function = uwb_rsv_timer;
+	rsv->timer.data     = (unsigned long)rsv;
+
+	rsv->rc = rc;
+
+	return rsv;
+}
+
+static void uwb_rsv_free(struct uwb_rsv *rsv)
+{
+	uwb_dev_put(rsv->owner);
+	if (rsv->target.type == UWB_RSV_TARGET_DEV)
+		uwb_dev_put(rsv->target.dev);
+	kfree(rsv);
+}
+
+/**
+ * uwb_rsv_create - allocate and initialize a UWB reservation structure
+ * @rc: the radio controller
+ * @cb: callback to use when the reservation completes or terminates
+ * @pal_priv: data private to the PAL to be passed in the callback
+ *
+ * The callback is called when the state of the reservation changes from:
+ *
+ *   - pending to accepted
+ *   - pending to denined
+ *   - accepted to terminated
+ *   - pending to terminated
+ */
+struct uwb_rsv *uwb_rsv_create(struct uwb_rc *rc, uwb_rsv_cb_f cb, void *pal_priv)
+{
+	struct uwb_rsv *rsv;
+
+	rsv = uwb_rsv_alloc(rc);
+	if (!rsv)
+		return NULL;
+
+	rsv->callback = cb;
+	rsv->pal_priv = pal_priv;
+
+	return rsv;
+}
+EXPORT_SYMBOL_GPL(uwb_rsv_create);
+
+void uwb_rsv_remove(struct uwb_rsv *rsv)
+{
+	if (rsv->state != UWB_RSV_STATE_NONE)
+		uwb_rsv_set_state(rsv, UWB_RSV_STATE_NONE);
+	del_timer_sync(&rsv->timer);
+	list_del(&rsv->rc_node);
+	uwb_rsv_free(rsv);
+}
+
+/**
+ * uwb_rsv_destroy - free a UWB reservation structure
+ * @rsv: the reservation to free
+ *
+ * The reservation will be terminated if it is pending or established.
+ */
+void uwb_rsv_destroy(struct uwb_rsv *rsv)
+{
+	struct uwb_rc *rc = rsv->rc;
+
+	mutex_lock(&rc->rsvs_mutex);
+	uwb_rsv_remove(rsv);
+	mutex_unlock(&rc->rsvs_mutex);
+}
+EXPORT_SYMBOL_GPL(uwb_rsv_destroy);
+
+/**
+ * usb_rsv_establish - start a reservation establishment
+ * @rsv: the reservation
+ *
+ * The PAL should fill in @rsv's owner, target, type, max_mas,
+ * min_mas, sparsity and is_multicast fields.  If the target is a
+ * uwb_dev it must be referenced.
+ *
+ * The reservation's callback will be called when the reservation is
+ * accepted, denied or times out.
+ */
+int uwb_rsv_establish(struct uwb_rsv *rsv)
+{
+	struct uwb_rc *rc = rsv->rc;
+	int ret;
+
+	mutex_lock(&rc->rsvs_mutex);
+
+	ret = uwb_rsv_get_stream(rsv);
+	if (ret)
+		goto out;
+
+	ret = uwb_rsv_alloc_mas(rsv);
+	if (ret) {
+		uwb_rsv_put_stream(rsv);
+		goto out;
+	}
+
+	list_add_tail(&rsv->rc_node, &rc->reservations);
+	rsv->owner = &rc->uwb_dev;
+	uwb_dev_get(rsv->owner);
+	uwb_rsv_set_state(rsv, UWB_RSV_STATE_O_INITIATED);
+out:
+	mutex_unlock(&rc->rsvs_mutex);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(uwb_rsv_establish);
+
+/**
+ * uwb_rsv_modify - modify an already established reservation
+ * @rsv: the reservation to modify
+ * @max_mas: new maximum MAS to reserve
+ * @min_mas: new minimum MAS to reserve
+ * @sparsity: new sparsity to use
+ *
+ * FIXME: implement this once there are PALs that use it.
+ */
+int uwb_rsv_modify(struct uwb_rsv *rsv, int max_mas, int min_mas, int sparsity)
+{
+	return -ENOSYS;
+}
+EXPORT_SYMBOL_GPL(uwb_rsv_modify);
+
+/**
+ * uwb_rsv_terminate - terminate an established reservation
+ * @rsv: the reservation to terminate
+ *
+ * A reservation is terminated by removing the DRP IE from the beacon,
+ * the other end will consider the reservation to be terminated when
+ * it does not see the DRP IE for at least mMaxLostBeacons.
+ *
+ * If applicable, the reference to the target uwb_dev will be released.
+ */
+void uwb_rsv_terminate(struct uwb_rsv *rsv)
+{
+	struct uwb_rc *rc = rsv->rc;
+
+	mutex_lock(&rc->rsvs_mutex);
+
+	uwb_rsv_set_state(rsv, UWB_RSV_STATE_NONE);
+
+	mutex_unlock(&rc->rsvs_mutex);
+}
+EXPORT_SYMBOL_GPL(uwb_rsv_terminate);
+
+/**
+ * uwb_rsv_accept - accept a new reservation from a peer
+ * @rsv:      the reservation
+ * @cb:       call back for reservation changes
+ * @pal_priv: data to be passed in the above call back
+ *
+ * Reservation requests from peers are denied unless a PAL accepts it
+ * by calling this function.
+ */
+void uwb_rsv_accept(struct uwb_rsv *rsv, uwb_rsv_cb_f cb, void *pal_priv)
+{
+	rsv->callback = cb;
+	rsv->pal_priv = pal_priv;
+	rsv->state    = UWB_RSV_STATE_T_ACCEPTED;
+}
+EXPORT_SYMBOL_GPL(uwb_rsv_accept);
+
+/*
+ * Is a received DRP IE for this reservation?
+ */
+static bool uwb_rsv_match(struct uwb_rsv *rsv, struct uwb_dev *src,
+			  struct uwb_ie_drp *drp_ie)
+{
+	struct uwb_dev_addr *rsv_src;
+	int stream;
+
+	stream = uwb_ie_drp_stream_index(drp_ie);
+
+	if (rsv->stream != stream)
+		return false;
+
+	switch (rsv->target.type) {
+	case UWB_RSV_TARGET_DEVADDR:
+		return rsv->stream == stream;
+	case UWB_RSV_TARGET_DEV:
+		if (uwb_ie_drp_owner(drp_ie))
+			rsv_src = &rsv->owner->dev_addr;
+		else
+			rsv_src = &rsv->target.dev->dev_addr;
+		return uwb_dev_addr_cmp(&src->dev_addr, rsv_src) == 0;
+	}
+	return false;
+}
+
+static struct uwb_rsv *uwb_rsv_new_target(struct uwb_rc *rc,
+					  struct uwb_dev *src,
+					  struct uwb_ie_drp *drp_ie)
+{
+	struct uwb_rsv *rsv;
+	struct uwb_pal *pal;
+	enum uwb_rsv_state state;
+
+	rsv = uwb_rsv_alloc(rc);
+	if (!rsv)
+		return NULL;
+
+	rsv->rc          = rc;
+	rsv->owner       = src;
+	uwb_dev_get(rsv->owner);
+	rsv->target.type = UWB_RSV_TARGET_DEV;
+	rsv->target.dev  = &rc->uwb_dev;
+	rsv->type        = uwb_ie_drp_type(drp_ie);
+	rsv->stream      = uwb_ie_drp_stream_index(drp_ie);
+	set_bit(rsv->stream, rsv->owner->streams);
+	uwb_drp_ie_to_bm(&rsv->mas, drp_ie);
+
+	/*
+	 * See if any PALs are interested in this reservation. If not,
+	 * deny the request.
+	 */
+	rsv->state = UWB_RSV_STATE_T_DENIED;
+	spin_lock(&rc->pal_lock);
+	list_for_each_entry(pal, &rc->pals, node) {
+		if (pal->new_rsv)
+			pal->new_rsv(rsv);
+		if (rsv->state == UWB_RSV_STATE_T_ACCEPTED)
+			break;
+	}
+	spin_unlock(&rc->pal_lock);
+
+	list_add_tail(&rsv->rc_node, &rc->reservations);
+	state = rsv->state;
+	rsv->state = UWB_RSV_STATE_NONE;
+	uwb_rsv_set_state(rsv, state);
+
+	return rsv;
+}
+
+/**
+ * uwb_rsv_find - find a reservation for a received DRP IE.
+ * @rc: the radio controller
+ * @src: source of the DRP IE
+ * @drp_ie: the DRP IE
+ *
+ * If the reservation cannot be found and the DRP IE is from a peer
+ * attempting to establish a new reservation, create a new reservation
+ * and add it to the list.
+ */
+struct uwb_rsv *uwb_rsv_find(struct uwb_rc *rc, struct uwb_dev *src,
+			     struct uwb_ie_drp *drp_ie)
+{
+	struct uwb_rsv *rsv;
+
+	list_for_each_entry(rsv, &rc->reservations, rc_node) {
+		if (uwb_rsv_match(rsv, src, drp_ie))
+			return rsv;
+	}
+
+	if (uwb_ie_drp_owner(drp_ie))
+		return uwb_rsv_new_target(rc, src, drp_ie);
+
+	return NULL;
+}
+
+/*
+ * Go through all the reservations and check for timeouts and (if
+ * necessary) update their DRP IEs.
+ *
+ * FIXME: look at building the SET_DRP_IE command here rather than
+ * having to rescan the list in uwb_rc_send_all_drp_ie().
+ */
+static bool uwb_rsv_update_all(struct uwb_rc *rc)
+{
+	struct uwb_rsv *rsv, *t;
+	bool ie_updated = false;
+
+	list_for_each_entry_safe(rsv, t, &rc->reservations, rc_node) {
+		if (rsv->expired)
+			uwb_drp_handle_timeout(rsv);
+		if (!rsv->ie_valid) {
+			uwb_drp_ie_update(rsv);
+			ie_updated = true;
+		}
+	}
+
+	return ie_updated;
+}
+
+void uwb_rsv_sched_update(struct uwb_rc *rc)
+{
+	queue_work(rc->rsv_workq, &rc->rsv_update_work);
+}
+
+/*
+ * Update DRP IEs and, if necessary, the DRP Availability IE and send
+ * the updated IEs to the radio controller.
+ */
+static void uwb_rsv_update_work(struct work_struct *work)
+{
+	struct uwb_rc *rc = container_of(work, struct uwb_rc, rsv_update_work);
+	bool ie_updated;
+
+	mutex_lock(&rc->rsvs_mutex);
+
+	ie_updated = uwb_rsv_update_all(rc);
+
+	if (!rc->drp_avail.ie_valid) {
+		uwb_drp_avail_ie_update(rc);
+		ie_updated = true;
+	}
+
+	if (ie_updated)
+		uwb_rc_send_all_drp_ie(rc);
+
+	mutex_unlock(&rc->rsvs_mutex);
+}
+
+static void uwb_rsv_timer(unsigned long arg)
+{
+	struct uwb_rsv *rsv = (struct uwb_rsv *)arg;
+
+	rsv->expired = true;
+	uwb_rsv_sched_update(rsv->rc);
+}
+
+void uwb_rsv_init(struct uwb_rc *rc)
+{
+	INIT_LIST_HEAD(&rc->reservations);
+	mutex_init(&rc->rsvs_mutex);
+	INIT_WORK(&rc->rsv_update_work, uwb_rsv_update_work);
+
+	bitmap_complement(rc->uwb_dev.streams, rc->uwb_dev.streams, UWB_NUM_STREAMS);
+}
+
+int uwb_rsv_setup(struct uwb_rc *rc)
+{
+	char name[16];
+
+	snprintf(name, sizeof(name), "%s_rsvd", dev_name(&rc->uwb_dev.dev));
+	rc->rsv_workq = create_singlethread_workqueue(name);
+	if (rc->rsv_workq == NULL)
+		return -ENOMEM;
+
+	return 0;
+}
+
+void uwb_rsv_cleanup(struct uwb_rc *rc)
+{
+	struct uwb_rsv *rsv, *t;
+
+	mutex_lock(&rc->rsvs_mutex);
+	list_for_each_entry_safe(rsv, t, &rc->reservations, rc_node) {
+		uwb_rsv_remove(rsv);
+	}
+	mutex_unlock(&rc->rsvs_mutex);
+
+	cancel_work_sync(&rc->rsv_update_work);
+	destroy_workqueue(rc->rsv_workq);
+}