nl80211/cfg80211: support VHT channel configuration

Change nl80211 to support specifying a VHT (or HT)
using the control channel frequency (as before) and
new attributes for the channel width and first and
second center frequency. The old channel type is of
course still supported for HT.

Also change the cfg80211 channel definition struct
to support these by adding the relevant fields to
it (and removing the _type field.)

This also adds new helper functions:
 - cfg80211_chandef_create to create a channel def
   struct given the control channel and channel type,
 - cfg80211_chandef_identical to check if two channel
   definitions are identical
 - cfg80211_chandef_compatible to check if the given
   channel definitions are compatible, and return the
   wider of the two

This isn't entirely complete, but that doesn't matter
until we have a driver using it. In particular, it's
missing
 - regulatory checks on the usable bandwidth (if that
   even makes sense)
 - regulatory TX power (database can't deal with it)
 - a proper channel compatibility calculation for the
   new channel types

Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 69 insertions, 4 deletions

diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index 86f777af79e8..977da58fb7ea 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -308,21 +308,86 @@ struct key_params {
 /**
  * struct cfg80211_chan_def - channel definition
  * @chan: the (control) channel
- * @_type: the channel type, don't use this field,
- *	use cfg80211_get_chandef_type() if needed.
+ * @width: channel width
+ * @center_freq1: center frequency of first segment
+ * @center_freq2: center frequency of second segment
+ *	(only with 80+80 MHz)
  */
 struct cfg80211_chan_def {
 	struct ieee80211_channel *chan;
-	enum nl80211_channel_type _type;
+	enum nl80211_chan_width width;
+	u32 center_freq1;
+	u32 center_freq2;
 };
 
+/**
+ * cfg80211_get_chandef_type - return old channel type from chandef
+ * @chandef: the channel definition
+ *
+ * Returns the old channel type (NOHT, HT20, HT40+/-) from a given
+ * chandef, which must have a bandwidth allowing this conversion.
+ */
 static inline enum nl80211_channel_type
 cfg80211_get_chandef_type(const struct cfg80211_chan_def *chandef)
 {
-	return chandef->_type;
+	switch (chandef->width) {
+	case NL80211_CHAN_WIDTH_20_NOHT:
+		return NL80211_CHAN_NO_HT;
+	case NL80211_CHAN_WIDTH_20:
+		return NL80211_CHAN_HT20;
+	case NL80211_CHAN_WIDTH_40:
+		if (chandef->center_freq1 > chandef->chan->center_freq)
+			return NL80211_CHAN_HT40PLUS;
+		return NL80211_CHAN_HT40MINUS;
+	default:
+		WARN_ON(1);
+		return NL80211_CHAN_NO_HT;
+	}
+}
+
+/**
+ * cfg80211_chandef_create - create channel definition using channel type
+ * @chandef: the channel definition struct to fill
+ * @channel: the control channel
+ * @chantype: the channel type
+ *
+ * Given a channel type, create a channel definition.
+ */
+void cfg80211_chandef_create(struct cfg80211_chan_def *chandef,
+			     struct ieee80211_channel *channel,
+			     enum nl80211_channel_type chantype);
+
+/**
+ * cfg80211_chandef_identical - check if two channel definitions are identical
+ * @chandef1: first channel definition
+ * @chandef2: second channel definition
+ *
+ * Returns %true if the channels defined by the channel definitions are
+ * identical, %false otherwise.
+ */
+static inline bool
+cfg80211_chandef_identical(const struct cfg80211_chan_def *chandef1,
+			   const struct cfg80211_chan_def *chandef2)
+{
+	return (chandef1->chan == chandef2->chan &&
+		chandef1->width == chandef2->width &&
+		chandef1->center_freq1 == chandef2->center_freq1 &&
+		chandef1->center_freq2 == chandef2->center_freq2);
 }
 
 /**
+ * cfg80211_chandef_compatible - check if two channel definitions are compatible
+ * @chandef1: first channel definition
+ * @chandef2: second channel definition
+ *
+ * Returns %NULL if the given channel definitions are incompatible,
+ * chandef1 or chandef2 otherwise.
+ */
+const struct cfg80211_chan_def *
+cfg80211_chandef_compatible(const struct cfg80211_chan_def *chandef1,
+			    const struct cfg80211_chan_def *chandef2);
+
+/**
  * enum survey_info_flags - survey information flags
  *
  * @SURVEY_INFO_NOISE_DBM: noise (in dBm) was filled in