wl1251: enforce changed hw encryption support on monitor state change

The firmware doesn't support per packet encryption selection, so disable hw
encryption support completely while a monitor interface is present to support
injection of packets (which shouldn't get encrypted by hw).
To enforce the changed hw encryption support force a disassociation on
non-monitor interfaces.
For disassociation a workaround using hw connection monitor is employed,
which temporary enables hw connection manager flag.

Signed-off-by: David Gnedt <david.gnedt@davizone.at>
Signed-off-by: Pali Rohár <pali.rohar@gmail.com>
Signed-off-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/ti/wl1251/main.c

@@ -687,6 +687,16 @@ static int wl1251_op_config(struct ieee80211_hw *hw, u32 changed)
 		wl->power_level = conf->power_level;
 	}
 
+	/*
+	 * Tell stack that connection is lost because hw encryption isn't
+	 * supported in monitor mode.
+	 * This requires temporary enabling of the hw connection monitor flag
+	 */
+	if ((changed & IEEE80211_CONF_CHANGE_MONITOR) && wl->vif) {
+		wl->hw->flags |= IEEE80211_HW_CONNECTION_MONITOR;
+		ieee80211_connection_loss(wl->vif);
+	}
+
 out_sleep:
 	wl1251_ps_elp_sleep(wl);
 
@@ -1119,6 +1129,9 @@ static void wl1251_op_bss_info_changed(struct ieee80211_hw *hw,
 	}
 
 	if (changed & BSS_CHANGED_ASSOC) {
+		/* Disable temporary enabled hw connection monitor flag */
+		wl->hw->flags &= ~IEEE80211_HW_CONNECTION_MONITOR;
+
 		if (bss_conf->assoc) {
 			wl->beacon_int = bss_conf->beacon_int;