iwlwifi: mvm: add a channel_switch op to bypass mac80211 timer

We need to call ieee80211_chswitch_done() ourselves just when the
absence TE started, so we perform the actual context switch early
enough.  To do so, add a dummy channel_switch op, which will cause
mac80211 to skip the countdown timer and allow us to call
ieee80211_chswitch_done() to complete the operation.
Signed-off-by: Luciano Coelho <luciano.coelho@intel.com>

drivers/net/wireless/iwlwifi/mvm/mac80211.c

@@ -3143,6 +3143,20 @@ static int iwl_mvm_mac_testmode_cmd(struct ieee80211_hw *hw,
 }
 #endif
 
+static void iwl_mvm_channel_switch(struct ieee80211_hw *hw,
+				   struct ieee80211_vif *vif,
+				   struct ieee80211_channel_switch *chsw)
+{
+	/* By implementing this operation, we prevent mac80211 from
+	 * starting its own channel switch timer, so that we can call
+	 * ieee80211_chswitch_done() ourselves at the right time
+	 * (which is when the absence time event starts).
+	 */
+
+	IWL_DEBUG_MAC80211(IWL_MAC80211_GET_MVM(hw),
+			   "dummy channel switch op\n");
+}
+
 static int iwl_mvm_pre_channel_switch(struct ieee80211_hw *hw,
 				      struct ieee80211_vif *vif,
 				      struct ieee80211_channel_switch *chsw)
@@ -3336,6 +3350,7 @@ const struct ieee80211_ops iwl_mvm_hw_ops = {
 
 	.set_tim = iwl_mvm_set_tim,
 
+	.channel_switch = iwl_mvm_channel_switch,
 	.pre_channel_switch = iwl_mvm_pre_channel_switch,
 	.post_channel_switch = iwl_mvm_post_channel_switch,
 

drivers/net/wireless/iwlwifi/mvm/time-event.c

@@ -207,6 +207,7 @@ iwl_mvm_te_handle_notify_csa(struct iwl_mvm *mvm,
 		break;
 	case NL80211_IFTYPE_STATION:
 		iwl_mvm_csa_client_absent(mvm, te_data->vif);
+		ieee80211_chswitch_done(te_data->vif, true);
 		break;
 	default:
 		/* should never happen */