1 /* 2 * This file contains helper code to handle channel 3 * settings and keeping track of what is possible at 4 * any point in time. 5 * 6 * Copyright 2009 Johannes Berg <johannes@sipsolutions.net> 7 */ 8 9 #include <net/cfg80211.h> 10 #include "core.h" 11 12 struct ieee80211_channel * 13 rdev_fixed_channel(struct cfg80211_registered_device *rdev, 14 struct wireless_dev *for_wdev) 15 { 16 struct wireless_dev *wdev; 17 struct ieee80211_channel *result = NULL; 18 19 WARN_ON(!mutex_is_locked(&rdev->devlist_mtx)); 20 21 list_for_each_entry(wdev, &rdev->netdev_list, list) { 22 if (wdev == for_wdev) 23 continue; 24 25 /* 26 * Lock manually to tell lockdep about allowed 27 * nesting here if for_wdev->mtx is held already. 28 * This is ok as it's all under the rdev devlist 29 * mutex and as such can only be done once at any 30 * given time. 31 */ 32 mutex_lock_nested(&wdev->mtx, SINGLE_DEPTH_NESTING); 33 if (wdev->current_bss) 34 result = wdev->current_bss->pub.channel; 35 wdev_unlock(wdev); 36 37 if (result) 38 break; 39 } 40 41 return result; 42 } 43 44 struct ieee80211_channel * 45 rdev_freq_to_chan(struct cfg80211_registered_device *rdev, 46 int freq, enum nl80211_channel_type channel_type) 47 { 48 struct ieee80211_channel *chan; 49 struct ieee80211_sta_ht_cap *ht_cap; 50 51 chan = ieee80211_get_channel(&rdev->wiphy, freq); 52 53 /* Primary channel not allowed */ 54 if (!chan || chan->flags & IEEE80211_CHAN_DISABLED) 55 return NULL; 56 57 if (channel_type == NL80211_CHAN_HT40MINUS && 58 chan->flags & IEEE80211_CHAN_NO_HT40MINUS) 59 return NULL; 60 else if (channel_type == NL80211_CHAN_HT40PLUS && 61 chan->flags & IEEE80211_CHAN_NO_HT40PLUS) 62 return NULL; 63 64 ht_cap = &rdev->wiphy.bands[chan->band]->ht_cap; 65 66 if (channel_type != NL80211_CHAN_NO_HT) { 67 if (!ht_cap->ht_supported) 68 return NULL; 69 70 if (!(ht_cap->cap & IEEE80211_HT_CAP_SUP_WIDTH_20_40) || 71 ht_cap->cap & IEEE80211_HT_CAP_40MHZ_INTOLERANT) 72 return NULL; 73 } 74 75 return chan; 76 } 77 78 int rdev_set_freq(struct cfg80211_registered_device *rdev, 79 struct wireless_dev *for_wdev, 80 int freq, enum nl80211_channel_type channel_type) 81 { 82 struct ieee80211_channel *chan; 83 int result; 84 85 if (rdev_fixed_channel(rdev, for_wdev)) 86 return -EBUSY; 87 88 if (!rdev->ops->set_channel) 89 return -EOPNOTSUPP; 90 91 chan = rdev_freq_to_chan(rdev, freq, channel_type); 92 if (!chan) 93 return -EINVAL; 94 95 result = rdev->ops->set_channel(&rdev->wiphy, chan, channel_type); 96 if (result) 97 return result; 98 99 rdev->channel = chan; 100 101 return 0; 102 } 103