carl9170: remove P2P_GO support

This patch follows up on a bug-report by Frank Schäfer that
discovered P2P GO wasn't working with wpa_supplicant.
This patch removes part of the broken P2P GO support but
keeps the vif switchover code in place.

Cc: <stable@vger.kernel.org>
Link: <https://lkml.kernel.org/r/3a9d86b6-744f-e670-8792-9167257edef8@googlemail.com>
Reported-by: Frank Schäfer <fschaefer.oss@googlemail.com>
Signed-off-by: Christian Lamparter <chunkeey@gmail.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20200425092811.9494-1-chunkeey@gmail.com

drivers/net/wireless/ath/carl9170/fw.c

@@ -338,9 +338,7 @@ static int carl9170_fw(struct ar9170 *ar, const __u8 *data, size_t len)
 		ar->hw->wiphy->interface_modes |= BIT(NL80211_IFTYPE_ADHOC);
 
 		if (SUPP(CARL9170FW_WLANTX_CAB)) {
-			if_comb_types |=
-				BIT(NL80211_IFTYPE_AP) |
-				BIT(NL80211_IFTYPE_P2P_GO);
+			if_comb_types |= BIT(NL80211_IFTYPE_AP);
 
 #ifdef CONFIG_MAC80211_MESH
 			if_comb_types |=

drivers/net/wireless/ath/carl9170/main.c

@@ -582,11 +582,10 @@ static int carl9170_init_interface(struct ar9170 *ar,
 	ar->disable_offload |= ((vif->type != NL80211_IFTYPE_STATION) &&
 	    (vif->type != NL80211_IFTYPE_AP));
 
-	/* While the driver supports HW offload in a single
-	 * P2P client configuration, it doesn't support HW
-	 * offload in the favourit, concurrent P2P GO+CLIENT
-	 * configuration. Hence, HW offload will always be
-	 * disabled for P2P.
+	/* The driver used to have P2P GO+CLIENT support,
+	 * but since this was dropped and we don't know if
+	 * there are any gremlins lurking in the shadows,
+	 * so best we keep HW offload disabled for P2P.
 	 */
 	ar->disable_offload |= vif->p2p;
 
@@ -639,18 +638,6 @@ static int carl9170_op_add_interface(struct ieee80211_hw *hw,
 			if (vif->type == NL80211_IFTYPE_STATION)
 				break;
 
-			/* P2P GO [master] use-case
-			 * Because the P2P GO station is selected dynamically
-			 * by all participating peers of a WIFI Direct network,
-			 * the driver has be able to change the main interface
-			 * operating mode on the fly.
-			 */
-			if (main_vif->p2p && vif->p2p &&
-			    vif->type == NL80211_IFTYPE_AP) {
-				old_main = main_vif;
-				break;
-			}
-
 			err = -EBUSY;
 			rcu_read_unlock();