mac80211: allow driver to impose WoWLAN restrictions

If the driver can't support WoWLAN in the current
state, this patch allows it to return 1 from the
suspend callback to do the normal deconfiguration
instead of using suspend/resume calls. Note that
if it does this, resume won't be called.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

include/net/mac80211.h

@@ -1628,6 +1628,10 @@ enum ieee80211_ampdu_mlme_action {
  *	ask the device to suspend. This is only invoked when WoWLAN is
  *	configured, otherwise the device is deconfigured completely and
  *	reconfigured at resume time.
+ *	The driver may also impose special conditions under which it
+ *	wants to use the "normal" suspend (deconfigure), say if it only
+ *	supports WoWLAN when the device is associated. In this case, it
+ *	must return 1 from this function.
  *
  * @resume: If WoWLAN was configured, this indicates that mac80211 is
  *	now resuming its operation, after this the device must be fully

net/mac80211/pm.c

@@ -72,15 +72,19 @@ int __ieee80211_suspend(struct ieee80211_hw *hw, struct cfg80211_wowlan *wowlan)
 	local->wowlan = wowlan && local->open_count;
 	if (local->wowlan) {
 		int err = drv_suspend(local, wowlan);
-		if (err) {
+		if (err < 0) {
 			local->quiescing = false;
 			return err;
+		} else if (err > 0) {
+			WARN_ON(err != 1);
+			local->wowlan = false;
+		} else {
+			list_for_each_entry(sdata, &local->interfaces, list) {
+				cancel_work_sync(&sdata->work);
+				ieee80211_quiesce(sdata);
+			}
+			goto suspend;
 		}
-		list_for_each_entry(sdata, &local->interfaces, list) {
-			cancel_work_sync(&sdata->work);
-			ieee80211_quiesce(sdata);
-		}
-		goto suspend;
 	}
 
 	/* disable keys */