brcmfmac: Workaround in change vif for wpa_supplicant support.

Different wpa_supplicants have different behavior and expectations
regarding the change_virtual_intf behavior. This patch implements
a workaround for the different versions and possible brcmfmac
configuration.
Reviewed-by: Arend Van Spriel <arend@broadcom.com>
Reviewed-by: Pieter-Paul Giesberts <pieterpg@broadcom.com>
Signed-off-by: Hante Meuleman <meuleman@broadcom.com>
Signed-off-by: Arend van Spriel <arend@broadcom.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/brcm80211/brcmfmac/cfg80211.c

@@ -777,6 +777,37 @@ brcmf_cfg80211_change_iface(struct wiphy *wiphy, struct net_device *ndev,
 	s32 err = 0;
 
 	brcmf_dbg(TRACE, "Enter, idx=%d, type=%d\n", ifp->bssidx, type);
+
+	/* WAR: There are a number of p2p interface related problems which
+	 * need to be handled initially (before doing the validate).
+	 * wpa_supplicant tends to do iface changes on p2p device/client/go
+	 * which are not always possible/allowed. However we need to return
+	 * OK otherwise the wpa_supplicant wont start. The situation differs
+	 * on configuration and setup (p2pon=1 module param). The first check
+	 * is to see if the request is a change to station for p2p iface.
+	 */
+	if ((type == NL80211_IFTYPE_STATION) &&
+	    ((vif->wdev.iftype == NL80211_IFTYPE_P2P_CLIENT) ||
+	     (vif->wdev.iftype == NL80211_IFTYPE_P2P_GO) ||
+	     (vif->wdev.iftype == NL80211_IFTYPE_P2P_DEVICE))) {
+		brcmf_dbg(TRACE, "Ignoring cmd for p2p if\n");
+		/* Now depending on whether module param p2pon=1 was used the
+		 * response needs to be either 0 or EOPNOTSUPP. The reason is
+		 * that if p2pon=1 is used, but a newer supplicant is used then
+		 * we should return an error, as this combination wont work.
+		 * In other situations 0 is returned and supplicant will start
+		 * normally. It will give a trace in cfg80211, but it is the
+		 * only way to get it working. Unfortunately this will result
+		 * in situation where we wont support new supplicant in
+		 * combination with module param p2pon=1, but that is the way
+		 * it is. If the user tries this then unloading of driver might
+		 * fail/lock.
+		 */
+		if (cfg->p2p.p2pdev_dynamically)
+			return -EOPNOTSUPP;
+		else
+			return 0;
+	}
 	err = brcmf_vif_change_validate(wiphy_to_cfg(wiphy), vif, type);
 	if (err) {
 		brcmf_err("iface validation failed: err=%d\n", err);
@@ -792,18 +823,6 @@ brcmf_cfg80211_change_iface(struct wiphy *wiphy, struct net_device *ndev,
 		infra = 0;
 		break;
 	case NL80211_IFTYPE_STATION:
-		/* Ignore change for p2p IF. Unclear why supplicant does this */
-		if ((vif->wdev.iftype == NL80211_IFTYPE_P2P_CLIENT) ||
-		    (vif->wdev.iftype == NL80211_IFTYPE_P2P_GO)) {
-			brcmf_dbg(TRACE, "Ignoring cmd for p2p if\n");
-			/* WAR: It is unexpected to get a change of VIF for P2P
-			 * IF, but it happens. The request can not be handled
-			 * but returning EPERM causes a crash. Returning 0
-			 * without setting ieee80211_ptr->iftype causes trace
-			 * (WARN_ON) but it works with wpa_supplicant
-			 */
-			return 0;
-		}
 		infra = 1;
 		break;
 	case NL80211_IFTYPE_AP: