1 files changed, 89 insertions, 0 deletions

diff --git a/net/wireless/chan.c b/net/wireless/chan.c
new file mode 100644
index 000000000000..a46ac6c9b365
--- /dev/null
+++ b/net/wireless/chan.c
@@ -0,0 +1,89 @@
+/*
+ * 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,
+                  struct wireless_dev *for_wdev,
+                  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, for_wdev))
+                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;
+}