1 files changed, 88 insertions, 0 deletions
diff --git a/net/wireless/chan.c b/net/wireless/chan.c
new file mode 100644
index 000000000000..bc00c9a06b3d
--- /dev/null
+++ b/net/wireless/chan.c
@@ -0,0 +1,88 @@
+/*
+ * This file contains helper code to handle channel
+ * settings and keeping track of what is possible at
+ * any point in time.
+ *
+ * Copyright 2009	Johannes Berg <johannes@sipsolutions.net>
+ */
+
+#include <net/cfg80211.h>
+#include "core.h"
+
+struct ieee80211_channel *
+rdev_fixed_channel(struct cfg80211_registered_device *rdev,
+		   struct wireless_dev *for_wdev)
+{
+	struct wireless_dev *wdev;
+	struct ieee80211_channel *result = NULL;
+
+	WARN_ON(!mutex_is_locked(&rdev->devlist_mtx));
+
+	list_for_each_entry(wdev, &rdev->netdev_list, list) {
+		if (wdev == for_wdev)
+			continue;
+
+		/*
+		 * Lock manually to tell lockdep about allowed
+		 * nesting here if for_wdev->mtx is held already.
+		 * This is ok as it's all under the rdev devlist
+		 * mutex and as such can only be done once at any
+		 * given time.
+		 */
+		mutex_lock_nested(&wdev->mtx, SINGLE_DEPTH_NESTING);
+		if (wdev->current_bss)
+			result = wdev->current_bss->pub.channel;
+		wdev_unlock(wdev);
+
+		if (result)
+			break;
+	}
+
+	return result;
+}
+
+int rdev_set_freq(struct cfg80211_registered_device *rdev,
+		  int freq, enum nl80211_channel_type channel_type)
+{
+	struct ieee80211_channel *chan;
+	struct ieee80211_sta_ht_cap *ht_cap;
+	int result;
+
+	if (rdev_fixed_channel(rdev, NULL))
+		return -EBUSY;
+
+	if (!rdev->ops->set_channel)
+		return -EOPNOTSUPP;
+
+	chan = ieee80211_get_channel(&rdev->wiphy, freq);
+
+	/* Primary channel not allowed */
+	if (!chan || chan->flags & IEEE80211_CHAN_DISABLED)
+		return -EINVAL;
+
+	if (channel_type == NL80211_CHAN_HT40MINUS &&
+	    chan->flags & IEEE80211_CHAN_NO_HT40MINUS)
+		return -EINVAL;
+	else if (channel_type == NL80211_CHAN_HT40PLUS &&
+		 chan->flags & IEEE80211_CHAN_NO_HT40PLUS)
+		return -EINVAL;
+
+	ht_cap = &rdev->wiphy.bands[chan->band]->ht_cap;
+
+	if (channel_type != NL80211_CHAN_NO_HT) {
+		if (!ht_cap->ht_supported)
+			return -EINVAL;
+
+		if (!(ht_cap->cap & IEEE80211_HT_CAP_SUP_WIDTH_20_40) ||
+		    ht_cap->cap & IEEE80211_HT_CAP_40MHZ_INTOLERANT)
+			return -EINVAL;
+	}
+
+	result = rdev->ops->set_channel(&rdev->wiphy, chan, channel_type);
+	if (result)
+		return result;
+
+	rdev->channel = chan;
+
+	return 0;
+}