cfg80211: treat 6 GHz channels as valid regardless of capability

If a 6 GHz channel exists, then we can probably safely assume that
the device actually supports it, and then it should support most
bandwidths.

This will probably need to be extended to check the interface type
and then dig into the HE capabilities for that though, to have the
correct bandwidth check.

Link: https://lore.kernel.org/r/20200528213443.d4864ef52e92.I82f09b2b14a56413ce20376d09967fe954a033eb@changeidSigned-off-by: NJohannes Berg <johannes.berg@intel.com>

net/wireless/chan.c

@@ -6,7 +6,7 @@
  *
  * Copyright 2009	Johannes Berg <johannes@sipsolutions.net>
  * Copyright 2013-2014  Intel Mobile Communications GmbH
- * Copyright 2018       Intel Corporation
+ * Copyright 2018-2020	Intel Corporation
  */
 
 #include <linux/export.h>
@@ -919,7 +919,8 @@ bool cfg80211_chandef_usable(struct wiphy *wiphy,
 		width = 10;
 		break;
 	case NL80211_CHAN_WIDTH_20:
-		if (!ht_cap->ht_supported)
+		if (!ht_cap->ht_supported &&
+		    chandef->chan->band != NL80211_BAND_6GHZ)
 			return false;
 		/* fall through */
 	case NL80211_CHAN_WIDTH_20_NOHT:
@@ -928,6 +929,8 @@ bool cfg80211_chandef_usable(struct wiphy *wiphy,
 		break;
 	case NL80211_CHAN_WIDTH_40:
 		width = 40;
+		if (chandef->chan->band == NL80211_BAND_6GHZ)
+			break;
 		if (!ht_cap->ht_supported)
 			return false;
 		if (!(ht_cap->cap & IEEE80211_HT_CAP_SUP_WIDTH_20_40) ||
@@ -942,24 +945,29 @@ bool cfg80211_chandef_usable(struct wiphy *wiphy,
 		break;
 	case NL80211_CHAN_WIDTH_80P80:
 		cap = vht_cap->cap & IEEE80211_VHT_CAP_SUPP_CHAN_WIDTH_MASK;
-		if (cap != IEEE80211_VHT_CAP_SUPP_CHAN_WIDTH_160_80PLUS80MHZ)
+		if (chandef->chan->band != NL80211_BAND_6GHZ &&
+		    cap != IEEE80211_VHT_CAP_SUPP_CHAN_WIDTH_160_80PLUS80MHZ)
 			return false;
 		/* fall through */
 	case NL80211_CHAN_WIDTH_80:
-		if (!vht_cap->vht_supported)
-			return false;
 		prohibited_flags |= IEEE80211_CHAN_NO_80MHZ;
 		width = 80;
+		if (chandef->chan->band == NL80211_BAND_6GHZ)
+			break;
+		if (!vht_cap->vht_supported)
+			return false;
 		break;
 	case NL80211_CHAN_WIDTH_160:
+		prohibited_flags |= IEEE80211_CHAN_NO_160MHZ;
+		width = 160;
+		if (chandef->chan->band == NL80211_BAND_6GHZ)
+			break;
 		if (!vht_cap->vht_supported)
 			return false;
 		cap = vht_cap->cap & IEEE80211_VHT_CAP_SUPP_CHAN_WIDTH_MASK;
 		if (cap != IEEE80211_VHT_CAP_SUPP_CHAN_WIDTH_160MHZ &&
 		    cap != IEEE80211_VHT_CAP_SUPP_CHAN_WIDTH_160_80PLUS80MHZ)
 			return false;
-		prohibited_flags |= IEEE80211_CHAN_NO_160MHZ;
-		width = 160;
 		break;
 	default:
 		WARN_ON_ONCE(1);