wil6210: limit fw error recovery attempts

In case there is something fundamentally wrong with the firmware
(example: RF cable disconnected), FW will always crash immediately
after reset. This leads to infinite fw error recovery loop.

Count consecutive unsuccessful error recovery attempts in a short period
of time, and stop doing recovery after some reasonable count.
It is still possible to manually reset fw doing
interface down/up sequence.

Signed-off-by: Vladimir Kondratiev <qca_vkondrat@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/ath/wil6210/main.c

@@ -161,12 +161,30 @@ static void wil_fw_error_worker(struct work_struct *work)
 	if (no_fw_recovery)
 		return;
 
+	/* increment @recovery_count if less then WIL6210_FW_RECOVERY_TO
+	 * passed since last recovery attempt
+	 */
+	if (time_is_after_jiffies(wil->last_fw_recovery +
+				  WIL6210_FW_RECOVERY_TO))
+		wil->recovery_count++;
+	else
+		wil->recovery_count = 1; /* fw was alive for a long time */
+
+	if (wil->recovery_count > WIL6210_FW_RECOVERY_RETRIES) {
+		wil_err(wil, "too many recovery attempts (%d), giving up\n",
+			wil->recovery_count);
+		return;
+	}
+
+	wil->last_fw_recovery = jiffies;
+
 	mutex_lock(&wil->mutex);
 	switch (wdev->iftype) {
 	case NL80211_IFTYPE_STATION:
 	case NL80211_IFTYPE_P2P_CLIENT:
 	case NL80211_IFTYPE_MONITOR:
-		wil_info(wil, "fw error recovery started...\n");
+		wil_info(wil, "fw error recovery started (try %d)...\n",
+			 wil->recovery_count);
 		wil_reset(wil);
 
 		/* need to re-allocate Rx ring after reset */
@@ -249,6 +267,8 @@ int wil_priv_init(struct wil6210_priv *wil)
 		return -EAGAIN;
 	}
 
+	wil->last_fw_recovery = jiffies;
+
 	return 0;
 }
 

drivers/net/wireless/ath/wil6210/wil6210.h

@@ -40,6 +40,8 @@ static inline u32 WIL_GET_BITS(u32 x, int b0, int b1)
 #define WIL6210_MAX_CID		(8) /* HW limit */
 #define WIL6210_NAPI_BUDGET	(16) /* arbitrary */
 #define WIL6210_ITR_TRSH	(10000) /* arbitrary - about 15 IRQs/msec */
+#define WIL6210_FW_RECOVERY_RETRIES	(5) /* try to recover this many times */
+#define WIL6210_FW_RECOVERY_TO	msecs_to_jiffies(5000)
 
 /* Hardware definitions begin */
 
@@ -361,6 +363,8 @@ struct wil6210_priv {
 	u32 fw_version;
 	u32 hw_version;
 	u8 n_mids; /* number of additional MIDs as reported by FW */
+	int recovery_count; /* num of FW recovery attempts in a short time */
+	unsigned long last_fw_recovery; /* jiffies of last fw recovery */
 	/* profile */
 	u32 monitor_flags;
 	u32 secure_pcp; /* create secure PCP? */