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/*
* 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;
}
struct ieee80211_channel *
rdev_freq_to_chan(struct cfg80211_registered_device *rdev,
int freq, enum nl80211_channel_type channel_type)
{
struct ieee80211_channel *chan;
struct ieee80211_sta_ht_cap *ht_cap;
chan = ieee80211_get_channel(&rdev->wiphy, freq);
/* Primary channel not allowed */
if (!chan || chan->flags & IEEE80211_CHAN_DISABLED)
return NULL;
if (channel_type == NL80211_CHAN_HT40MINUS &&
chan->flags & IEEE80211_CHAN_NO_HT40MINUS)
return NULL;
else if (channel_type == NL80211_CHAN_HT40PLUS &&
chan->flags & IEEE80211_CHAN_NO_HT40PLUS)
return NULL;
ht_cap = &rdev->wiphy.bands[chan->band]->ht_cap;
if (channel_type != NL80211_CHAN_NO_HT) {
if (!ht_cap->ht_supported)
return NULL;
if (!(ht_cap->cap & IEEE80211_HT_CAP_SUP_WIDTH_20_40) ||
ht_cap->cap & IEEE80211_HT_CAP_40MHZ_INTOLERANT)
return NULL;
}
return chan;
}
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;
int result;
if (rdev_fixed_channel(rdev, for_wdev))
return -EBUSY;
if (!rdev->ops->set_channel)
return -EOPNOTSUPP;
chan = rdev_freq_to_chan(rdev, freq, channel_type);
if (!chan)
return -EINVAL;
result = rdev->ops->set_channel(&rdev->wiphy, chan, channel_type);
if (result)
return result;
rdev->channel = chan;
return 0;
}
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