openwrt/package/mac80211/patches/523-mac80211_configure_antenna_gain.patch

--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -955,6 +955,7 @@ enum ieee80211_smps_mode {
  *
  * @power_level: requested transmit power (in dBm), backward compatibility
  *	value only that is set to the minimum of all interfaces
+ * @max_antenna_gain: maximum antenna gain adjusted by user config (in dBi)
  *
  * @channel: the channel to tune to
  * @channel_type: the channel (HT) type
@@ -976,6 +977,7 @@ struct ieee80211_conf {
 	u32 flags;
 	int power_level, dynamic_ps_timeout;
 	int max_sleep_period;
+	int max_antenna_gain;
 
 	u16 listen_interval;
 	u8 ps_dtim_period;
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -1132,6 +1132,7 @@ struct ieee80211_local {
 	bool disable_dynamic_ps;
 
 	int user_power_level; /* in dBm, for all interfaces */
+	int user_antenna_gain; /* in dBi */
 
 	enum ieee80211_smps_mode smps_mode;
 
--- a/include/uapi/linux/nl80211.h
+++ b/include/uapi/linux/nl80211.h
@@ -1580,6 +1580,8 @@ enum nl80211_attrs {
 	NL80211_ATTR_P2P_CTWINDOW,
 	NL80211_ATTR_P2P_OPPPS,
 
+	NL80211_ATTR_WIPHY_ANTENNA_GAIN,
+
 	/* add attributes here, update the policy in nl80211.c */
 
 	__NL80211_ATTR_AFTER_LAST,
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -365,6 +365,7 @@ static const struct nla_policy nl80211_p
 	[NL80211_ATTR_SCAN_FLAGS] = { .type = NLA_U32 },
 	[NL80211_ATTR_P2P_CTWINDOW] = { .type = NLA_U8 },
 	[NL80211_ATTR_P2P_OPPPS] = { .type = NLA_U8 },
+	[NL80211_ATTR_WIPHY_ANTENNA_GAIN] = { .type = NLA_U32 },
 };
 
 /* policy for the key attributes */
@@ -1652,6 +1653,22 @@ static int nl80211_set_wiphy(struct sk_b
 			goto bad_res;
 	}
 
+	if (info->attrs[NL80211_ATTR_WIPHY_ANTENNA_GAIN]) {
+		int idx, dbi = 0;
+
+		if (!rdev->ops->set_antenna_gain) {
+			result = -EOPNOTSUPP;
+			goto bad_res;
+		}
+
+		idx = NL80211_ATTR_WIPHY_ANTENNA_GAIN;
+		dbi = nla_get_u32(info->attrs[idx]);
+
+		result = rdev->ops->set_antenna_gain(&rdev->wiphy, dbi);
+		if (result)
+			goto bad_res;
+	}
+
 	if (info->attrs[NL80211_ATTR_WIPHY_ANTENNA_TX] &&
 	    info->attrs[NL80211_ATTR_WIPHY_ANTENNA_RX]) {
 		u32 tx_ant, rx_ant;
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -2118,6 +2118,19 @@ static int ieee80211_get_tx_power(struct
 	return 0;
 }
 
+static int ieee80211_set_antenna_gain(struct wiphy *wiphy, int dbi)
+{
+	struct ieee80211_local *local = wiphy_priv(wiphy);
+
+	if (dbi < 0)
+		return -EINVAL;
+
+	local->user_antenna_gain = dbi;
+	ieee80211_hw_config(local, 0);
+
+	return 0;
+}
+
 static int ieee80211_set_wds_peer(struct wiphy *wiphy, struct net_device *dev,
 				  const u8 *addr)
 {
@@ -3241,6 +3254,7 @@ struct cfg80211_ops mac80211_config_ops 
 	.set_wiphy_params = ieee80211_set_wiphy_params,
 	.set_tx_power = ieee80211_set_tx_power,
 	.get_tx_power = ieee80211_get_tx_power,
+	.set_antenna_gain = ieee80211_set_antenna_gain,
 	.set_wds_peer = ieee80211_set_wds_peer,
 	.rfkill_poll = ieee80211_rfkill_poll,
 	CFG80211_TESTMODE_CMD(ieee80211_testmode_cmd)
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -1693,6 +1693,7 @@ struct cfg80211_gtk_rekey_data {
  *	(as advertised by the nl80211 feature flag.)
  * @get_tx_power: store the current TX power into the dbm variable;
  *	return 0 if successful
+ * @set_antenna_gain: set antenna gain to reduce maximum tx power if necessary
  *
  * @set_wds_peer: set the WDS peer for a WDS interface
  *
@@ -1893,6 +1894,7 @@ struct cfg80211_ops {
 				enum nl80211_tx_power_setting type, int mbm);
 	int	(*get_tx_power)(struct wiphy *wiphy, struct wireless_dev *wdev,
 				int *dbm);
+	int	(*set_antenna_gain)(struct wiphy *wiphy, int dbi);
 
 	int	(*set_wds_peer)(struct wiphy *wiphy, struct net_device *dev,
 				const u8 *addr);
--- a/net/mac80211/main.c
+++ b/net/mac80211/main.c
@@ -102,7 +102,7 @@ static u32 ieee80211_hw_conf_chan(struct
 	struct ieee80211_sub_if_data *sdata;
 	struct ieee80211_channel *chan;
 	u32 changed = 0;
-	int power;
+	int power, ant_gain, max_power;
 	enum nl80211_channel_type channel_type;
 	u32 offchannel_flag;
 	bool scanning = false;
@@ -165,8 +165,21 @@ static u32 ieee80211_hw_conf_chan(struct
 	}
 	rcu_read_unlock();
 
-	if (local->hw.conf.power_level != power) {
+	max_power = chan->max_reg_power;
+	ant_gain = chan->max_antenna_gain;
+	if (local->user_antenna_gain > 0) {
+		if (local->user_antenna_gain > ant_gain) {
+			max_power -= local->user_antenna_gain - ant_gain;
+			ant_gain = 0;
+		} else
+			ant_gain -= local->user_antenna_gain;
+	}
+
+	power = min(chan->max_power, max_power);
+	if (local->hw.conf.power_level != power ||
+		local->hw.conf.max_antenna_gain != ant_gain) {
 		changed |= IEEE80211_CONF_CHANGE_POWER;
+		local->hw.conf.max_antenna_gain = ant_gain;
 		local->hw.cur_power_level = power;
 		local->hw.conf.power_level = power;
 	}
@@ -646,6 +659,7 @@ struct ieee80211_hw *ieee80211_alloc_hw(
 					 IEEE80211_RADIOTAP_MCS_HAVE_BW;
 	local->hw.radiotap_vht_details = IEEE80211_RADIOTAP_VHT_KNOWN_GI |
 					 IEEE80211_RADIOTAP_VHT_KNOWN_BANDWIDTH;
+	local->user_antenna_gain = 0;
 	local->user_power_level = IEEE80211_UNSET_POWER_LEVEL;
 	wiphy->ht_capa_mod_mask = &mac80211_ht_capa_mod_mask;