iwlwifi:mvm: Add AP/GO channel switch support

Publish WIPHY_FLAG_HAS_CHANNEL_SWITCH if the fw supports
newly introduced IWL_UCODE_TLV_API_CSA_FLOW.
When CSA starts, save the switching vif inside mvm and during the CSA period
configure fw with a new beacon after each beacon transmission in order to
update the csa counters.
Also, handle correctly the CSA unbind-bind flow which is triggered by mac80211
when the actual channel switch happens.

Signed-off-by: Andrei Otcheretianski <andrei.otcheretianski@intel.com>
Reviewed-by: Luciano Coelho <luciano.coelho@intel.com>
Reviewed-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>

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

@@ -320,6 +320,9 @@ int iwl_mvm_mac_setup_register(struct iwl_mvm *mvm)
 	if (mvm->fw->ucode_capa.flags & IWL_UCODE_TLV_FLAGS_GO_UAPSD)
 		hw->wiphy->flags |= WIPHY_FLAG_AP_UAPSD;
 
+	if (mvm->fw->ucode_capa.api[0] & IWL_UCODE_TLV_API_CSA_FLOW)
+		hw->wiphy->flags |= WIPHY_FLAG_HAS_CHANNEL_SWITCH;
+
 	hw->wiphy->iface_combinations = iwl_mvm_iface_combinations;
 	hw->wiphy->n_iface_combinations =
 		ARRAY_SIZE(iwl_mvm_iface_combinations);
@@ -2198,6 +2201,11 @@ static int iwl_mvm_assign_vif_chanctx(struct ieee80211_hw *hw,
 
 	switch (vif->type) {
 	case NL80211_IFTYPE_AP:
+		/* Unless it's a CSA flow we have nothing to do here */
+		if (vif->csa_active) {
+			mvmvif->ap_ibss_active = true;
+			break;
+		}
 	case NL80211_IFTYPE_ADHOC:
 		/*
 		 * The AP binding flow is handled as part of the start_ap flow
@@ -2234,6 +2242,12 @@ static int iwl_mvm_assign_vif_chanctx(struct ieee80211_hw *hw,
 			goto out_remove_binding;
 	}
 
+	/* Handle binding during CSA */
+	if (vif->type == NL80211_IFTYPE_AP) {
+		iwl_mvm_update_quotas(mvm, vif);
+		iwl_mvm_mac_ctxt_changed(mvm, vif);
+	}
+
 	goto out_unlock;
 
  out_remove_binding:
@@ -2258,13 +2272,20 @@ static void iwl_mvm_unassign_vif_chanctx(struct ieee80211_hw *hw,
 	iwl_mvm_remove_time_event(mvm, mvmvif, &mvmvif->time_event_data);
 
 	switch (vif->type) {
-	case NL80211_IFTYPE_AP:
 	case NL80211_IFTYPE_ADHOC:
 		goto out_unlock;
 	case NL80211_IFTYPE_MONITOR:
 		mvmvif->monitor_active = false;
 		iwl_mvm_update_quotas(mvm, NULL);
 		break;
+	case NL80211_IFTYPE_AP:
+		/* This part is triggered only during CSA */
+		if (!vif->csa_active || !mvmvif->ap_ibss_active)
+			goto out_unlock;
+
+		mvmvif->ap_ibss_active = false;
+		iwl_mvm_update_quotas(mvm, NULL);
+		/*TODO: bt_coex notification here? */
 	default:
 		break;
 	}
@@ -2360,6 +2381,25 @@ static int iwl_mvm_mac_testmode_cmd(struct ieee80211_hw *hw,
 }
 #endif
 
+static void iwl_mvm_channel_switch_beacon(struct ieee80211_hw *hw,
+					  struct ieee80211_vif *vif,
+					  struct cfg80211_chan_def *chandef)
+{
+	struct iwl_mvm *mvm = IWL_MAC80211_GET_MVM(hw);
+
+	mutex_lock(&mvm->mutex);
+	if (WARN(mvm->csa_vif && mvm->csa_vif->csa_active,
+		 "Another CSA is already in progress"))
+		goto out_unlock;
+
+	IWL_DEBUG_MAC80211(mvm, "CSA started to freq %d\n",
+			   chandef->center_freq1);
+	mvm->csa_vif = vif;
+
+out_unlock:
+	mutex_unlock(&mvm->mutex);
+}
+
 const struct ieee80211_ops iwl_mvm_hw_ops = {
 	.tx = iwl_mvm_mac_tx,
 	.ampdu_action = iwl_mvm_mac_ampdu_action,
@@ -2402,6 +2442,8 @@ const struct ieee80211_ops iwl_mvm_hw_ops = {
 
 	.set_tim = iwl_mvm_set_tim,
 
+	.channel_switch_beacon = iwl_mvm_channel_switch_beacon,
+
 	CFG80211_TESTMODE_CMD(iwl_mvm_mac_testmode_cmd)
 
 #ifdef CONFIG_PM_SLEEP