wl1271: Check interface state in op_* functions

Check the state of the interface on op_* function so we don't try to access
the hardware in when its off.

The mac80211 may call these in some corner cases related, for instance, to
the hardware recovery procedure. These accesses cause a kernel crash on at
least some SDIO devices, because the bus is not properly claimed in that
scenario.
Signed-off-by: Juuso Oikarinen <juuso.oikarinen@nokia.com>
Reviewed-by: Luciano Coelho <luciano.coelho@nokia.com>
Signed-off-by: Luciano Coelho <luciano.coelho@nokia.com>

drivers/net/wireless/wl12xx/wl1271_main.c

@@ -1344,8 +1344,10 @@ static int wl1271_op_config(struct ieee80211_hw *hw, u32 changed)
 
 	mutex_lock(&wl->mutex);
 
-	if (unlikely(wl->state == WL1271_STATE_OFF))
+	if (unlikely(wl->state == WL1271_STATE_OFF)) {
+		ret = -EAGAIN;
 		goto out;
+	}
 
 	ret = wl1271_ps_elp_wakeup(wl, false);
 	if (ret < 0)
@@ -1568,6 +1570,11 @@ static int wl1271_op_set_key(struct ieee80211_hw *hw, enum set_key_cmd cmd,
 
 	mutex_lock(&wl->mutex);
 
+	if (unlikely(wl->state == WL1271_STATE_OFF)) {
+		ret = -EAGAIN;
+		goto out_unlock;
+	}
+
 	ret = wl1271_ps_elp_wakeup(wl, false);
 	if (ret < 0)
 		goto out_unlock;
@@ -1708,8 +1715,10 @@ static int wl1271_op_set_rts_threshold(struct ieee80211_hw *hw, u32 value)
 
 	mutex_lock(&wl->mutex);
 
-	if (unlikely(wl->state == WL1271_STATE_OFF))
+	if (unlikely(wl->state == WL1271_STATE_OFF)) {
+		ret = -EAGAIN;
 		goto out;
+	}
 
 	ret = wl1271_ps_elp_wakeup(wl, false);
 	if (ret < 0)
@@ -1760,6 +1769,9 @@ static void wl1271_op_bss_info_changed(struct ieee80211_hw *hw,
 
 	mutex_lock(&wl->mutex);
 
+	if (unlikely(wl->state == WL1271_STATE_OFF))
+		goto out;
+
 	ret = wl1271_ps_elp_wakeup(wl, false);
 	if (ret < 0)
 		goto out;
@@ -2040,6 +2052,11 @@ static int wl1271_op_conf_tx(struct ieee80211_hw *hw, u16 queue,
 
 	wl1271_debug(DEBUG_MAC80211, "mac80211 conf tx %d", queue);
 
+	if (unlikely(wl->state == WL1271_STATE_OFF)) {
+		ret = -EAGAIN;
+		goto out;
+	}
+
 	ret = wl1271_ps_elp_wakeup(wl, false);
 	if (ret < 0)
 		goto out;
@@ -2083,6 +2100,9 @@ static u64 wl1271_op_get_tsf(struct ieee80211_hw *hw)
 
 	mutex_lock(&wl->mutex);
 
+	if (unlikely(wl->state == WL1271_STATE_OFF))
+		goto out;
+
 	ret = wl1271_ps_elp_wakeup(wl, false);
 	if (ret < 0)
 		goto out;