wifi: rtw89: avoid inaccessible IO operations during doing change_interface()

During doing change_interface(), hardware is power-off, so some components
are inaccessible and return error. This causes things unexpected, and we
don't have a warning message for that. So, ignore some IO operations in
this situation, and add a warning message to indicate something wrong.
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20221117085235.53777-1-pkshih@realtek.com

drivers/net/wireless/realtek/rtw89/core.h

@@ -2968,6 +2968,7 @@ enum rtw89_flags {
 	RTW89_FLAG_CRASH_SIMULATING,
 	RTW89_FLAG_WOWLAN,
 	RTW89_FLAG_FORBIDDEN_TRACK_WROK,
+	RTW89_FLAG_CHANGING_INTERFACE,
 
 	NUM_OF_RTW89_FLAGS,
 };

drivers/net/wireless/realtek/rtw89/mac.c

@@ -3600,6 +3600,13 @@ int rtw89_mac_set_macid_pause(struct rtw89_dev *rtwdev, u8 macid, bool pause)
 	u8 grp = macid >> 5;
 	int ret;
 
+	/* If this is called by change_interface() in the case of P2P, it could
+	 * be power-off, so ignore this operation.
+	 */
+	if (test_bit(RTW89_FLAG_CHANGING_INTERFACE, rtwdev->flags) &&
+	    !test_bit(RTW89_FLAG_POWERON, rtwdev->flags))
+		return 0;
+
 	ret = rtw89_mac_check_mac_en(rtwdev, RTW89_MAC_0, RTW89_CMAC_SEL);
 	if (ret)
 		return ret;

drivers/net/wireless/realtek/rtw89/mac80211.c

@@ -174,6 +174,9 @@ static int rtw89_ops_change_interface(struct ieee80211_hw *hw,
 				      enum nl80211_iftype type, bool p2p)
 {
 	struct rtw89_dev *rtwdev = hw->priv;
+	int ret;
+
+	set_bit(RTW89_FLAG_CHANGING_INTERFACE, rtwdev->flags);
 
 	rtw89_debug(rtwdev, RTW89_DBG_STATE, "change vif %pM (%d)->(%d), p2p (%d)->(%d)\n",
 		    vif->addr, vif->type, type, vif->p2p, p2p);
@@ -183,7 +186,13 @@ static int rtw89_ops_change_interface(struct ieee80211_hw *hw,
 	vif->type = type;
 	vif->p2p = p2p;
 
-	return rtw89_ops_add_interface(hw, vif);
+	ret = rtw89_ops_add_interface(hw, vif);
+	if (ret)
+		rtw89_warn(rtwdev, "failed to change interface %d\n", ret);
+
+	clear_bit(RTW89_FLAG_CHANGING_INTERFACE, rtwdev->flags);
+
+	return ret;
 }
 
 static void rtw89_ops_configure_filter(struct ieee80211_hw *hw,