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, 229 insertions, 20 deletions

diff --git a/net/wireless/chan.c b/net/wireless/chan.c
index e834422de40a..bf2dfd54ff3b 100644
--- a/net/wireless/chan.c
+++ b/net/wireless/chan.c
@@ -11,43 +11,252 @@
 #include "core.h"
 #include "rdev-ops.h"
 
-bool cfg80211_reg_can_beacon(struct wiphy *wiphy,
-			     struct cfg80211_chan_def *chandef)
+void cfg80211_chandef_create(struct cfg80211_chan_def *chandef,
+			     struct ieee80211_channel *chan,
+			     enum nl80211_channel_type chan_type)
 {
-	struct ieee80211_channel *sec_chan;
-	int diff;
+	if (WARN_ON(!chan))
+		return;
 
-	trace_cfg80211_reg_can_beacon(wiphy, chandef);
+	chandef->chan = chan;
+	chandef->center_freq2 = 0;
 
-	switch (chandef->_type) {
+	switch (chan_type) {
+	case NL80211_CHAN_NO_HT:
+		chandef->width = NL80211_CHAN_WIDTH_20_NOHT;
+		chandef->center_freq1 = chan->center_freq;
+		break;
+	case NL80211_CHAN_HT20:
+		chandef->width = NL80211_CHAN_WIDTH_20;
+		chandef->center_freq1 = chan->center_freq;
+		break;
 	case NL80211_CHAN_HT40PLUS:
-		diff = 20;
+		chandef->width = NL80211_CHAN_WIDTH_40;
+		chandef->center_freq1 = chan->center_freq + 10;
 		break;
 	case NL80211_CHAN_HT40MINUS:
-		diff = -20;
+		chandef->width = NL80211_CHAN_WIDTH_40;
+		chandef->center_freq1 = chan->center_freq - 10;
+		break;
+	default:
+		WARN_ON(1);
+	}
+}
+EXPORT_SYMBOL(cfg80211_chandef_create);
+
+bool cfg80211_chan_def_valid(const struct cfg80211_chan_def *chandef)
+{
+	u32 control_freq;
+
+	if (!chandef->chan)
+		return false;
+
+	control_freq = chandef->chan->center_freq;
+
+	switch (chandef->width) {
+	case NL80211_CHAN_WIDTH_20:
+	case NL80211_CHAN_WIDTH_20_NOHT:
+		if (chandef->center_freq1 != control_freq)
+			return false;
+		if (chandef->center_freq2)
+			return false;
+		break;
+	case NL80211_CHAN_WIDTH_40:
+		if (chandef->center_freq1 != control_freq + 10 &&
+		    chandef->center_freq1 != control_freq - 10)
+			return false;
+		if (chandef->center_freq2)
+			return false;
+		break;
+	case NL80211_CHAN_WIDTH_80P80:
+		if (chandef->center_freq1 != control_freq + 30 &&
+		    chandef->center_freq1 != control_freq + 10 &&
+		    chandef->center_freq1 != control_freq - 10 &&
+		    chandef->center_freq1 != control_freq - 30)
+			return false;
+		if (!chandef->center_freq2)
+			return false;
+		break;
+	case NL80211_CHAN_WIDTH_80:
+		if (chandef->center_freq1 != control_freq + 30 &&
+		    chandef->center_freq1 != control_freq + 10 &&
+		    chandef->center_freq1 != control_freq - 10 &&
+		    chandef->center_freq1 != control_freq - 30)
+			return false;
+		if (chandef->center_freq2)
+			return false;
+		break;
+	case NL80211_CHAN_WIDTH_160:
+		if (chandef->center_freq1 != control_freq + 70 &&
+		    chandef->center_freq1 != control_freq + 50 &&
+		    chandef->center_freq1 != control_freq + 30 &&
+		    chandef->center_freq1 != control_freq + 10 &&
+		    chandef->center_freq1 != control_freq - 10 &&
+		    chandef->center_freq1 != control_freq - 30 &&
+		    chandef->center_freq1 != control_freq - 50 &&
+		    chandef->center_freq1 != control_freq - 70)
+			return false;
+		if (chandef->center_freq2)
+			return false;
+		break;
+	default:
+		return false;
+	}
+
+	return true;
+}
+
+static void chandef_primary_freqs(const struct cfg80211_chan_def *c,
+				  int *pri40, int *pri80)
+{
+	int tmp;
+
+	switch (c->width) {
+	case NL80211_CHAN_WIDTH_40:
+		*pri40 = c->center_freq1;
+		*pri80 = 0;
+		break;
+	case NL80211_CHAN_WIDTH_80:
+	case NL80211_CHAN_WIDTH_80P80:
+		*pri80 = c->center_freq1;
+		/* n_P20 */
+		tmp = (30 + c->chan->center_freq - c->center_freq1)/20;
+		/* n_P40 */
+		tmp /= 2;
+		/* freq_P40 */
+		*pri40 = c->center_freq1 - 20 + 40 * tmp;
+		break;
+	case NL80211_CHAN_WIDTH_160:
+		/* n_P20 */
+		tmp = (70 + c->chan->center_freq - c->center_freq1)/20;
+		/* n_P40 */
+		tmp /= 2;
+		/* freq_P40 */
+		*pri40 = c->center_freq1 - 60 + 40 * tmp;
+		/* n_P80 */
+		tmp /= 2;
+		*pri80 = c->center_freq1 - 40 + 80 * tmp;
 		break;
 	default:
-		trace_cfg80211_return_bool(true);
-		return true;
+		WARN_ON_ONCE(1);
 	}
+}
+
+const struct cfg80211_chan_def *
+cfg80211_chandef_compatible(const struct cfg80211_chan_def *c1,
+			    const struct cfg80211_chan_def *c2)
+{
+	u32 c1_pri40, c1_pri80, c2_pri40, c2_pri80;
 
-	sec_chan = ieee80211_get_channel(wiphy,
-					 chandef->chan->center_freq + diff);
-	if (!sec_chan) {
+	/* If they are identical, return */
+	if (cfg80211_chandef_identical(c1, c2))
+		return c1;
+
+	/* otherwise, must have same control channel */
+	if (c1->chan != c2->chan)
+		return NULL;
+
+	/*
+	 * If they have the same width, but aren't identical,
+	 * then they can't be compatible.
+	 */
+	if (c1->width == c2->width)
+		return NULL;
+
+	if (c1->width == NL80211_CHAN_WIDTH_20_NOHT ||
+	    c1->width == NL80211_CHAN_WIDTH_20)
+		return c2;
+
+	if (c2->width == NL80211_CHAN_WIDTH_20_NOHT ||
+	    c2->width == NL80211_CHAN_WIDTH_20)
+		return c1;
+
+	chandef_primary_freqs(c1, &c1_pri40, &c1_pri80);
+	chandef_primary_freqs(c2, &c2_pri40, &c2_pri80);
+
+	if (c1_pri40 != c2_pri40)
+		return NULL;
+
+	WARN_ON(!c1_pri80 && !c2_pri80);
+	if (c1_pri80 && c2_pri80 && c1_pri80 != c2_pri80)
+		return NULL;
+
+	if (c1->width > c2->width)
+		return c1;
+	return c2;
+}
+EXPORT_SYMBOL(cfg80211_chandef_compatible);
+
+bool cfg80211_secondary_chans_ok(struct wiphy *wiphy,
+				 u32 center_freq, u32 bandwidth,
+				 u32 prohibited_flags)
+{
+	struct ieee80211_channel *c;
+	u32 freq;
+
+	for (freq = center_freq - bandwidth/2 + 10;
+	     freq <= center_freq + bandwidth/2 - 10;
+	     freq += 20) {
+		c = ieee80211_get_channel(wiphy, freq);
+		if (!c || c->flags & prohibited_flags)
+			return false;
+	}
+
+	return true;
+}
+
+static bool cfg80211_check_beacon_chans(struct wiphy *wiphy,
+					u32 center_freq, u32 bw)
+{
+	return cfg80211_secondary_chans_ok(wiphy, center_freq, bw,
+					   IEEE80211_CHAN_DISABLED |
+					   IEEE80211_CHAN_PASSIVE_SCAN |
+					   IEEE80211_CHAN_NO_IBSS |
+					   IEEE80211_CHAN_RADAR);
+}
+
+bool cfg80211_reg_can_beacon(struct wiphy *wiphy,
+			     struct cfg80211_chan_def *chandef)
+{
+	u32 width;
+	bool res;
+
+	trace_cfg80211_reg_can_beacon(wiphy, chandef);
+
+	if (WARN_ON(!cfg80211_chan_def_valid(chandef))) {
 		trace_cfg80211_return_bool(false);
 		return false;
 	}
 
-	/* we'll need a DFS capability later */
-	if (sec_chan->flags & (IEEE80211_CHAN_DISABLED |
-			       IEEE80211_CHAN_PASSIVE_SCAN |
-			       IEEE80211_CHAN_NO_IBSS |
-			       IEEE80211_CHAN_RADAR)) {
+	switch (chandef->width) {
+	case NL80211_CHAN_WIDTH_20_NOHT:
+	case NL80211_CHAN_WIDTH_20:
+		width = 20;
+		break;
+	case NL80211_CHAN_WIDTH_40:
+		width = 40;
+		break;
+	case NL80211_CHAN_WIDTH_80:
+	case NL80211_CHAN_WIDTH_80P80:
+		width = 80;
+		break;
+	case NL80211_CHAN_WIDTH_160:
+		width = 160;
+		break;
+	default:
+		WARN_ON_ONCE(1);
 		trace_cfg80211_return_bool(false);
 		return false;
 	}
-	trace_cfg80211_return_bool(true);
-	return true;
+
+	res = cfg80211_check_beacon_chans(wiphy, chandef->center_freq1, width);
+
+	if (res && chandef->center_freq2)
+		res = cfg80211_check_beacon_chans(wiphy, chandef->center_freq2,
+						  width);
+
+	trace_cfg80211_return_bool(res);
+	return res;
 }
 EXPORT_SYMBOL(cfg80211_reg_can_beacon);