wcn36xx: Treat repeated BMPS entry fail as connection loss

On an open AP when you pull the plug on the AP, if we are not already in
BMPS mode then the firmware will not generate a disconnection event.

Instead we need to monitor for failure to enter BMPS and treat a string of
failures as connection loss.

Secure AP connections don't appear to demonstrate this behavior so the
work-around is limited to open APs only.
Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20211022140447.2846248-2-bryan.odonoghue@linaro.org

drivers/net/wireless/ath/wcn36xx/pmc.c

@@ -18,6 +18,8 @@
 
 #include "wcn36xx.h"
 
+#define WCN36XX_BMPS_FAIL_THREHOLD 3
+
 int wcn36xx_pmc_enter_bmps_state(struct wcn36xx *wcn,
 				 struct ieee80211_vif *vif)
 {
@@ -31,6 +33,7 @@ int wcn36xx_pmc_enter_bmps_state(struct wcn36xx *wcn,
 	if (!ret) {
 		wcn36xx_dbg(WCN36XX_DBG_PMC, "Entered BMPS\n");
 		vif_priv->pw_state = WCN36XX_BMPS;
+		vif_priv->bmps_fail_ct = 0;
 		vif->driver_flags |= IEEE80211_VIF_BEACON_FILTER;
 	} else {
 		/*
@@ -39,6 +42,11 @@ int wcn36xx_pmc_enter_bmps_state(struct wcn36xx *wcn,
 		 * received just after auth complete
 		 */
 		wcn36xx_err("Can not enter BMPS!\n");
+
+		if (vif_priv->bmps_fail_ct++ == WCN36XX_BMPS_FAIL_THREHOLD) {
+			ieee80211_connection_loss(vif);
+			vif_priv->bmps_fail_ct = 0;
+		}
 	}
 	return ret;
 }

drivers/net/wireless/ath/wcn36xx/wcn36xx.h

@@ -151,6 +151,8 @@ struct wcn36xx_vif {
 	} rekey_data;
 
 	struct list_head sta_list;
+
+	int bmps_fail_ct;
 };
 
 /**