ath9k_htc: Handle device unplug properly

When the USB device has been unplugged, there is
no point in trying to send commands to the target.
Fix this by denying all WMI commands in such a case.

Signed-off-by: Sujith <Sujith.Manoharan@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/ath/ath9k/htc.h

@@ -329,6 +329,7 @@ struct htc_beacon_config {
 #define OP_ASSOCIATED     BIT(8)
 #define OP_ENABLE_BEACON  BIT(9)
 #define OP_LED_DEINIT     BIT(10)
+#define OP_UNPLUGGED      BIT(11)
 
 struct ath9k_htc_priv {
 	struct device *dev;

drivers/net/wireless/ath/ath9k/htc_drv_init.c

@@ -744,6 +744,9 @@ int ath9k_htc_probe_device(struct htc_target *htc_handle, struct device *dev,
 	if (ret)
 		goto err_init;
 
+	/* The device may have been unplugged earlier. */
+	priv->op_flags &= ~OP_UNPLUGGED;
+
 	ret = ath9k_init_device(priv, devid);
 	if (ret)
 		goto err_init;
@@ -760,6 +763,11 @@ int ath9k_htc_probe_device(struct htc_target *htc_handle, struct device *dev,
 void ath9k_htc_disconnect_device(struct htc_target *htc_handle, bool hotunplug)
 {
 	if (htc_handle->drv_priv) {
+
+		/* Check if the device has been yanked out. */
+		if (hotunplug)
+			htc_handle->drv_priv->op_flags |= OP_UNPLUGGED;
+
 		ath9k_deinit_device(htc_handle->drv_priv);
 		ath9k_deinit_wmi(htc_handle->drv_priv);
 		ieee80211_free_hw(htc_handle->drv_priv->hw);

drivers/net/wireless/ath/ath9k/wmi.c

@@ -276,6 +276,9 @@ int ath9k_wmi_cmd(struct wmi *wmi, enum wmi_cmd_id cmd_id,
 	int time_left, ret = 0;
 	unsigned long flags;
 
+	if (wmi->drv_priv->op_flags & OP_UNPLUGGED)
+		return 0;
+
 	if (!wmi)
 		return -EINVAL;