iwlwifi: keep track of bt coex enable/disable stage

For debugging purpose, keep track of the bt coex enable/disable state.
Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>

drivers/net/wireless/iwlwifi/iwl-agn-debugfs.c

@@ -856,6 +856,9 @@ ssize_t iwl_ucode_bt_stats_read(struct file *file,
 	if (!iwl_is_alive(priv))
 		return -EAGAIN;
 
+	if (!priv->bt_enable_flag)
+		return -EINVAL;
+
 	/* make request to uCode to retrieve statistics information */
 	mutex_lock(&priv->mutex);
 	ret = iwl_send_statistics_request(priv, CMD_SYNC, false);

drivers/net/wireless/iwlwifi/iwl-agn-lib.c

@@ -1845,6 +1845,7 @@ void iwlagn_send_advance_bt_config(struct iwl_priv *priv)
 			bt_cmd.flags |= IWLAGN_BT_FLAG_CHANNEL_INHIBITION;
 		IWL_DEBUG_INFO(priv, "BT coex flag: 0X%x\n", bt_cmd.flags);
 	}
+	priv->bt_enable_flag = bt_cmd.flags;
 	if (priv->bt_full_concurrent)
 		memcpy(bt_cmd.bt3_lookup_table, iwlagn_concurrent_lookup,
 			sizeof(iwlagn_concurrent_lookup));

drivers/net/wireless/iwlwifi/iwl-core.c

@@ -1223,6 +1223,7 @@ void iwl_send_bt_config(struct iwl_priv *priv)
 	else
 		bt_cmd.flags = BT_COEX_ENABLE;
 
+	priv->bt_enable_flag = bt_cmd.flags;
 	IWL_DEBUG_INFO(priv, "BT coex %s\n",
 		(bt_cmd.flags == BT_COEX_DISABLE) ? "disable" : "active");
 

drivers/net/wireless/iwlwifi/iwl-debugfs.c

@@ -1567,6 +1567,13 @@ static ssize_t iwl_dbgfs_bt_traffic_read(struct file *file,
 	const size_t bufsz = sizeof(buf);
 	ssize_t ret;
 
+	if (!priv->bt_enable_flag) {
+		pos += scnprintf(buf + pos, bufsz - pos, "BT coex disabled\n");
+		ret = simple_read_from_buffer(user_buf, count, ppos, buf, pos);
+		return ret;
+	}
+	pos += scnprintf(buf + pos, bufsz - pos, "BT enable flag: 0x%x\n",
+		priv->bt_enable_flag);
 	pos += scnprintf(buf + pos, bufsz - pos, "BT in %s mode\n",
 		priv->bt_full_concurrent ? "full concurrency" : "3-wire");
 	pos += scnprintf(buf + pos, bufsz - pos, "BT status: %s, "

drivers/net/wireless/iwlwifi/iwl-dev.h

@@ -1468,6 +1468,7 @@ struct iwl_priv {
 	};
 
 	/* bt coex */
+	u8 bt_enable_flag;
 	u8 bt_status;
 	u8 bt_traffic_load, last_bt_traffic_load;
 	bool bt_ch_announce;