uwb: add basic radio manager

The UWB radio manager coordinates the use of the radio between the
PALs that may be using it.  PALs request use of the radio with
uwb_radio_start() and the radio manager will start beaconing if its
not already doing so.  When the last PAL has called uwb_radio_stop()
beaconing will be stopped.

In the future, the radio manager will have a more sophisticated channel
selection algorithm, probably following the Channel Selection Policy
from the WiMedia Alliance when it is finalized.  For now, channel 9
(BG1, TFC1) is selected.

The user may override the channel selected by the radio manager and may
force the radio to stop beaconing.

The WUSB Host Controller PAL makes use of this and there are two new
debug PAL commands that can be used for testing.

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

11 files changed, 261 insertions, 69 deletions

diff --git a/drivers/uwb/Makefile b/drivers/uwb/Makefile
index 2b99c3e..ce21a95 100644
--- a/drivers/uwb/Makefile
+++ b/drivers/uwb/Makefile
@@ -18,6 +18,7 @@ uwb-objs :=		\
 	lc-rc.o		\
 	neh.o		\
 	pal.o		\
+	radio.o		\
 	reset.o		\
 	rsv.o		\
 	scan.o		\
diff --git a/drivers/uwb/beacon.c b/drivers/uwb/beacon.c
index d9f2a8a..2479560 100644
--- a/drivers/uwb/beacon.c
+++ b/drivers/uwb/beacon.c
@@ -119,7 +119,6 @@ int uwb_rc_beacon(struct uwb_rc *rc, int channel, unsigned bpst_offset)
 	int result;
 	struct device *dev = &rc->uwb_dev.dev;
 
-	mutex_lock(&rc->uwb_dev.mutex);
 	if (channel < 0)
 		channel = -1;
 	if (channel == -1)
@@ -128,7 +127,7 @@ int uwb_rc_beacon(struct uwb_rc *rc, int channel, unsigned bpst_offset)
 		/* channel >= 0...dah */
 		result = uwb_rc_start_beacon(rc, bpst_offset, channel);
 		if (result < 0)
-			goto out_up;
+			return result;
 		if (le16_to_cpu(rc->ies->wIELength) > 0) {
 			result = uwb_rc_set_ie(rc, rc->ies);
 			if (result < 0) {
@@ -137,19 +136,14 @@ int uwb_rc_beacon(struct uwb_rc *rc, int channel, unsigned bpst_offset)
 				result = uwb_rc_stop_beacon(rc);
 				channel = -1;
 				bpst_offset = 0;
-			} else
-				result = 0;
+			}
 		}
 	}
 
-	if (result < 0)
-		goto out_up;
-	rc->beaconing = channel;
-
-	uwb_notify(rc, NULL, uwb_bg_joined(rc) ? UWB_NOTIF_BG_JOIN : UWB_NOTIF_BG_LEAVE);
-
-out_up:
-	mutex_unlock(&rc->uwb_dev.mutex);
+	if (result >= 0) {
+		rc->beaconing = channel;
+		uwb_notify(rc, NULL, uwb_bg_joined(rc) ? UWB_NOTIF_BG_JOIN : UWB_NOTIF_BG_LEAVE);
+	}
 	return result;
 }
 
@@ -618,9 +612,6 @@ static ssize_t uwb_rc_beacon_show(struct device *dev,
 
 /*
  * Start beaconing on the specified channel, or stop beaconing.
- *
- * The BPST offset of when to start searching for a beacon group to
- * join may be specified.
  */
 static ssize_t uwb_rc_beacon_store(struct device *dev,
 				   struct device_attribute *attr,
@@ -629,12 +620,11 @@ static ssize_t uwb_rc_beacon_store(struct device *dev,
 	struct uwb_dev *uwb_dev = to_uwb_dev(dev);
 	struct uwb_rc *rc = uwb_dev->rc;
 	int channel;
-	unsigned bpst_offset = 0;
 	ssize_t result = -EINVAL;
 
-	result = sscanf(buf, "%d %u\n", &channel, &bpst_offset);
+	result = sscanf(buf, "%d", &channel);
 	if (result >= 1)
-		result = uwb_rc_beacon(rc, channel, bpst_offset);
+		result = uwb_radio_force_channel(rc, channel);
 
 	return result < 0 ? result : size;
 }
diff --git a/drivers/uwb/drp.c b/drivers/uwb/drp.c
index c0b1e5e..fe32814 100644
--- a/drivers/uwb/drp.c
+++ b/drivers/uwb/drp.c
@@ -37,14 +37,13 @@
  *
  * A DRP Availability IE is appended.
  *
- * rc->uwb_dev.mutex is held
+ * rc->rsvs_mutex is held
  *
  * FIXME We currently ignore the returned value indicating the remaining space
  * in beacon. This could be used to deny reservation requests earlier if
  * determined that they would cause the beacon space to be exceeded.
  */
-static
-int uwb_rc_gen_send_drp_ie(struct uwb_rc *rc)
+int uwb_rc_send_all_drp_ie(struct uwb_rc *rc)
 {
 	int result;
 	struct device *dev = &rc->uwb_dev.dev;
@@ -102,25 +101,6 @@ error_cmd:
 	kfree(cmd);
 error:
 	return result;
-
-}
-/**
- * Send all DRP IEs associated with this host
- *
- * @returns:    >= 0 number of bytes still available in the beacon
- *              < 0 errno code on error.
- *
- * As per the protocol we obtain the host controller device lock to access
- * bandwidth structures.
- */
-int uwb_rc_send_all_drp_ie(struct uwb_rc *rc)
-{
-	int result;
-
-	mutex_lock(&rc->uwb_dev.mutex);
-	result = uwb_rc_gen_send_drp_ie(rc);
-	mutex_unlock(&rc->uwb_dev.mutex);
-	return result;
 }
 
 void uwb_drp_handle_timeout(struct uwb_rsv *rsv)
diff --git a/drivers/uwb/lc-rc.c b/drivers/uwb/lc-rc.c
index f00633d..9cf21e6 100644
--- a/drivers/uwb/lc-rc.c
+++ b/drivers/uwb/lc-rc.c
@@ -189,9 +189,9 @@ static int uwb_rc_setup(struct uwb_rc *rc)
 	int result;
 	struct device *dev = &rc->uwb_dev.dev;
 
-	result = uwb_rc_reset(rc);
+	result = uwb_radio_setup(rc);
 	if (result < 0) {
-		dev_err(dev, "cannot reset UWB radio: %d\n", result);
+		dev_err(dev, "cannot setup UWB radio: %d\n", result);
 		goto error;
 	}
 	result = uwb_rc_mac_addr_setup(rc);
@@ -311,12 +311,7 @@ void uwb_rc_rm(struct uwb_rc *rc)
 
 	uwb_dbg_del_rc(rc);
 	uwb_rsv_remove_all(rc);
-	uwb_rc_ie_rm(rc, UWB_IDENTIFICATION_IE);
-	if (rc->beaconing >= 0)
-		uwb_rc_beacon(rc, -1, 0);
-	if (rc->scan_type != UWB_SCAN_DISABLED)
-		uwb_rc_scan(rc, rc->scanning, UWB_SCAN_DISABLED, 0);
-	uwb_rc_reset(rc);
+	uwb_radio_shutdown(rc);
 
 	rc->stop(rc);
 
diff --git a/drivers/uwb/pal.c b/drivers/uwb/pal.c
index 1afb38e..6057651 100644
--- a/drivers/uwb/pal.c
+++ b/drivers/uwb/pal.c
@@ -32,13 +32,13 @@ EXPORT_SYMBOL_GPL(uwb_pal_init);
 
 /**
  * uwb_pal_register - register a UWB PAL
- * @rc: the radio controller the PAL will be using
  * @pal: the PAL
  *
  * The PAL must be initialized with uwb_pal_init().
  */
-int uwb_pal_register(struct uwb_rc *rc, struct uwb_pal *pal)
+int uwb_pal_register(struct uwb_pal *pal)
 {
+	struct uwb_rc *rc = pal->rc;
 	int ret;
 
 	if (pal->device) {
@@ -54,9 +54,9 @@ int uwb_pal_register(struct uwb_rc *rc, struct uwb_pal *pal)
 		}
 	}
 
-	spin_lock(&rc->pal_lock);
+	mutex_lock(&rc->uwb_dev.mutex);
 	list_add(&pal->node, &rc->pals);
-	spin_unlock(&rc->pal_lock);
+	mutex_unlock(&rc->uwb_dev.mutex);
 
 	return 0;
 }
@@ -64,14 +64,17 @@ EXPORT_SYMBOL_GPL(uwb_pal_register);
 
 /**
  * uwb_pal_register - unregister a UWB PAL
- * @rc: the radio controller the PAL was using
  * @pal: the PAL
  */
-void uwb_pal_unregister(struct uwb_rc *rc, struct uwb_pal *pal)
+void uwb_pal_unregister(struct uwb_pal *pal)
 {
-	spin_lock(&rc->pal_lock);
+	struct uwb_rc *rc = pal->rc;
+
+	uwb_radio_stop(pal);
+
+	mutex_lock(&rc->uwb_dev.mutex);
 	list_del(&pal->node);
-	spin_unlock(&rc->pal_lock);
+	mutex_unlock(&rc->uwb_dev.mutex);
 
 	if (pal->device) {
 		sysfs_remove_link(&rc->uwb_dev.dev.kobj, pal->name);
@@ -86,6 +89,5 @@ EXPORT_SYMBOL_GPL(uwb_pal_unregister);
  */
 void uwb_rc_pal_init(struct uwb_rc *rc)
 {
-	spin_lock_init(&rc->pal_lock);
 	INIT_LIST_HEAD(&rc->pals);
 }
diff --git a/drivers/uwb/radio.c b/drivers/uwb/radio.c
new file mode 100644
index 0000000..f0d5549
--- /dev/null
+++ b/drivers/uwb/radio.c
@@ -0,0 +1,202 @@
+/*
+ * UWB radio (channel) 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/kernel.h>
+#include <linux/uwb.h>
+
+#include "uwb-internal.h"
+
+
+static int uwb_radio_select_channel(struct uwb_rc *rc)
+{
+	/*
+	 * Default to channel 9 (BG1, TFC1) unless the user has
+	 * selected a specific channel or there are no active PALs.
+	 */
+	if (rc->active_pals == 0)
+		return -1;
+	if (rc->beaconing_forced)
+		return rc->beaconing_forced;
+	return 9;
+}
+
+
+/*
+ * Notify all active PALs that the channel has changed.
+ */
+static void uwb_radio_channel_changed(struct uwb_rc *rc, int channel)
+{
+	struct uwb_pal *pal;
+
+	list_for_each_entry(pal, &rc->pals, node) {
+		if (pal->channel && channel != pal->channel) {
+			pal->channel = channel;
+			if (pal->channel_changed)
+				pal->channel_changed(pal, pal->channel);
+		}
+	}
+}
+
+/*
+ * Change to a new channel and notify any active PALs of the new
+ * channel.
+ *
+ * When stopping the radio, PALs need to be notified first so they can
+ * terminate any active reservations.
+ */
+static int uwb_radio_change_channel(struct uwb_rc *rc, int channel)
+{
+	int ret = 0;
+
+	if (channel == -1)
+		uwb_radio_channel_changed(rc, channel);
+
+	if (channel != rc->beaconing) {
+		if (rc->beaconing != -1 && channel != -1) {
+			/*
+			 * FIXME: should signal the channel change
+			 * with a Channel Change IE.
+			 */
+			ret = uwb_radio_change_channel(rc, -1);
+			if (ret < 0)
+				return ret;
+		}
+		ret = uwb_rc_beacon(rc, channel, 0);
+	}
+
+	if (channel != -1)
+		uwb_radio_channel_changed(rc, rc->beaconing);
+
+	return ret;
+}
+
+/**
+ * uwb_radio_start - request that the radio be started
+ * @pal: the PAL making the request.
+ *
+ * If the radio is not already active, aa suitable channel is selected
+ * and beacons are started.
+ */
+int uwb_radio_start(struct uwb_pal *pal)
+{
+	struct uwb_rc *rc = pal->rc;
+	int ret = 0;
+
+	mutex_lock(&rc->uwb_dev.mutex);
+
+	if (!pal->channel) {
+		pal->channel = -1;
+		rc->active_pals++;
+		ret = uwb_radio_change_channel(rc, uwb_radio_select_channel(rc));
+	}
+
+	mutex_unlock(&rc->uwb_dev.mutex);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(uwb_radio_start);
+
+/**
+ * uwb_radio_stop - request tha the radio be stopped.
+ * @pal: the PAL making the request.
+ *
+ * Stops the radio if no other PAL is making use of it.
+ */
+void uwb_radio_stop(struct uwb_pal *pal)
+{
+	struct uwb_rc *rc = pal->rc;
+
+	mutex_lock(&rc->uwb_dev.mutex);
+
+	if (pal->channel) {
+		rc->active_pals--;
+		uwb_radio_change_channel(rc, uwb_radio_select_channel(rc));
+		pal->channel = 0;
+	}
+
+	mutex_unlock(&rc->uwb_dev.mutex);
+}
+EXPORT_SYMBOL_GPL(uwb_radio_stop);
+
+/*
+ * uwb_radio_force_channel - force a specific channel to be used
+ * @rc: the radio controller.
+ * @channel: the channel to use; -1 to force the radio to stop; 0 to
+ *   use the default channel selection algorithm.
+ */
+int uwb_radio_force_channel(struct uwb_rc *rc, int channel)
+{
+	int ret = 0;
+
+	mutex_lock(&rc->uwb_dev.mutex);
+
+	rc->beaconing_forced = channel;
+	ret = uwb_radio_change_channel(rc, uwb_radio_select_channel(rc));
+
+	mutex_unlock(&rc->uwb_dev.mutex);
+	return ret;
+}
+
+/*
+ * uwb_radio_setup - setup the radio manager
+ * @rc: the radio controller.
+ *
+ * The radio controller is reset to ensure it's in a known state
+ * before it's used.
+ */
+int uwb_radio_setup(struct uwb_rc *rc)
+{
+	return uwb_rc_reset(rc);
+}
+
+/*
+ * uwb_radio_reset_state - reset any radio manager state
+ * @rc: the radio controller.
+ *
+ * All internal radio manager state is reset to values corresponding
+ * to a reset radio controller.
+ */
+void uwb_radio_reset_state(struct uwb_rc *rc)
+{
+	struct uwb_pal *pal;
+
+	mutex_lock(&rc->uwb_dev.mutex);
+
+	list_for_each_entry(pal, &rc->pals, node) {
+		if (pal->channel) {
+			pal->channel = -1;
+			if (pal->channel_changed)
+				pal->channel_changed(pal, -1);
+		}
+	}
+
+	rc->beaconing = -1;
+	rc->scanning = -1;
+
+	mutex_unlock(&rc->uwb_dev.mutex);
+}
+
+/*
+ * uwb_radio_shutdown - shutdown the radio manager
+ * @rc: the radio controller.
+ *
+ * The radio controller is reset.
+ */
+void uwb_radio_shutdown(struct uwb_rc *rc)
+{
+	uwb_radio_reset_state(rc);
+	uwb_rc_reset(rc);
+}
diff --git a/drivers/uwb/reset.c b/drivers/uwb/reset.c
index e39b320..ce8283c 100644
--- a/drivers/uwb/reset.c
+++ b/drivers/uwb/reset.c
@@ -365,11 +365,7 @@ void uwb_rc_pre_reset(struct uwb_rc *rc)
 	rc->stop(rc);
 	uwbd_flush(rc);
 
-	mutex_lock(&rc->uwb_dev.mutex);
-	rc->beaconing = -1;
-	rc->scanning = -1;
-	mutex_unlock(&rc->uwb_dev.mutex);
-
+	uwb_radio_reset_state(rc);
 	uwb_rsv_remove_all(rc);
 }
 EXPORT_SYMBOL_GPL(uwb_rc_pre_reset);
diff --git a/drivers/uwb/rsv.c b/drivers/uwb/rsv.c
index 935d5b5..1cd84f9 100644
--- a/drivers/uwb/rsv.c
+++ b/drivers/uwb/rsv.c
@@ -555,14 +555,14 @@ static struct uwb_rsv *uwb_rsv_new_target(struct uwb_rc *rc,
 	 * deny the request.
 	 */
 	rsv->state = UWB_RSV_STATE_T_DENIED;
-	spin_lock(&rc->pal_lock);
+	mutex_lock(&rc->uwb_dev.mutex);
 	list_for_each_entry(pal, &rc->pals, node) {
 		if (pal->new_rsv)
 			pal->new_rsv(pal, rsv);
 		if (rsv->state == UWB_RSV_STATE_T_ACCEPTED)
 			break;
 	}
-	spin_unlock(&rc->pal_lock);
+	mutex_unlock(&rc->uwb_dev.mutex);
 
 	list_add_tail(&rsv->rc_node, &rc->reservations);
 	state = rsv->state;
diff --git a/drivers/uwb/uwb-debug.c b/drivers/uwb/uwb-debug.c
index 217ebaa..0e58071 100644
--- a/drivers/uwb/uwb-debug.c
+++ b/drivers/uwb/uwb-debug.c
@@ -192,7 +192,7 @@ static ssize_t command_write(struct file *file, const char __user *buf,
 {
 	struct uwb_rc *rc = file->private_data;
 	struct uwb_dbg_cmd cmd;
-	int ret;
+	int ret = 0;
 
 	if (len != sizeof(struct uwb_dbg_cmd))
 		return -EINVAL;
@@ -213,6 +213,12 @@ static ssize_t command_write(struct file *file, const char __user *buf,
 	case UWB_DBG_CMD_IE_RM:
 		ret = cmd_ie_rm(rc, &cmd.ie_rm);
 		break;
+	case UWB_DBG_CMD_RADIO_START:
+		ret = uwb_radio_start(&rc->dbg->pal);
+		break;
+	case UWB_DBG_CMD_RADIO_STOP:
+		uwb_radio_stop(&rc->dbg->pal);
+		break;
 	default:
 		return -EINVAL;
 	}
@@ -306,6 +312,17 @@ static struct file_operations drp_avail_fops = {
 	.owner   = THIS_MODULE,
 };
 
+static void uwb_dbg_channel_changed(struct uwb_pal *pal, int channel)
+{
+	struct uwb_dbg *dbg = container_of(pal, struct uwb_dbg, pal);
+	struct device *dev = &pal->rc->uwb_dev.dev;
+
+	if (channel > 0)
+		dev_info(dev, "debug: channel %d started\n", channel);
+	else
+		dev_info(dev, "debug: channel stopped\n");
+}
+
 static void uwb_dbg_new_rsv(struct uwb_pal *pal, struct uwb_rsv *rsv)
 {
 	struct uwb_dbg *dbg = container_of(pal, struct uwb_dbg, pal);
@@ -329,8 +346,11 @@ void uwb_dbg_add_rc(struct uwb_rc *rc)
 	INIT_LIST_HEAD(&rc->dbg->rsvs);
 
 	uwb_pal_init(&rc->dbg->pal);
+	rc->dbg->pal.rc = rc;
+	rc->dbg->pal.channel_changed = uwb_dbg_channel_changed;
 	rc->dbg->pal.new_rsv = uwb_dbg_new_rsv;
-	uwb_pal_register(rc, &rc->dbg->pal);
+	uwb_pal_register(&rc->dbg->pal);
+
 	if (root_dir) {
 		rc->dbg->root_d = debugfs_create_dir(dev_name(&rc->uwb_dev.dev),
 						     root_dir);
@@ -364,7 +384,7 @@ void uwb_dbg_del_rc(struct uwb_rc *rc)
 		uwb_rsv_terminate(rsv);
 	}
 
-	uwb_pal_unregister(rc, &rc->dbg->pal);
+	uwb_pal_unregister(&rc->dbg->pal);
 
 	if (root_dir) {
 		debugfs_remove(rc->dbg->drp_avail_f);
diff --git a/drivers/uwb/uwb-internal.h b/drivers/uwb/uwb-internal.h
index af95541..9c0cdb4 100644
--- a/drivers/uwb/uwb-internal.h
+++ b/drivers/uwb/uwb-internal.h
@@ -238,6 +238,11 @@ struct uwb_dev *uwb_dev_get_by_devaddr(struct uwb_rc *rc,
 struct uwb_dev *uwb_dev_get_by_macaddr(struct uwb_rc *rc,
 				       const struct uwb_mac_addr *macaddr);
 
+int uwb_radio_setup(struct uwb_rc *rc);
+void uwb_radio_reset_state(struct uwb_rc *rc);
+void uwb_radio_shutdown(struct uwb_rc *rc);
+int uwb_radio_force_channel(struct uwb_rc *rc, int channel);
+
 /* -- UWB Sysfs representation */
 extern struct class uwb_rc_class;
 extern struct device_attribute dev_attr_mac_address;
diff --git a/drivers/uwb/wlp/wlp-lc.c b/drivers/uwb/wlp/wlp-lc.c
index 0799402..7e5eb49 100644
--- a/drivers/uwb/wlp/wlp-lc.c
+++ b/drivers/uwb/wlp/wlp-lc.c
@@ -543,7 +543,8 @@ int wlp_setup(struct wlp *wlp, struct uwb_rc *rc)
 	uwb_notifs_register(rc, &wlp->uwb_notifs_handler);
 
 	uwb_pal_init(&wlp->pal);
-	result = uwb_pal_register(rc, &wlp->pal);
+	wlp->pal.rc = rc;
+	result = uwb_pal_register(&wlp->pal);
 	if (result < 0)
 		uwb_notifs_deregister(wlp->rc, &wlp->uwb_notifs_handler);
 
@@ -557,7 +558,7 @@ void wlp_remove(struct wlp *wlp)
 	struct device *dev = &wlp->rc->uwb_dev.dev;
 	d_fnstart(6, dev, "wlp %p\n", wlp);
 	wlp_neighbors_release(wlp);
-	uwb_pal_unregister(wlp->rc, &wlp->pal);
+	uwb_pal_unregister(&wlp->pal);
 	uwb_notifs_deregister(wlp->rc, &wlp->uwb_notifs_handler);
 	wlp_eda_release(&wlp->eda);
 	mutex_lock(&wlp->mutex);