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-rw-r--r--net/wireless/chan.c88
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;
+}