drivers: wifi: simplelink: add timeout for fast connect feature

The SimpleLink wifi driver enables the Fast Connect method of
WiFi provisioning, which allows the network coprocessor to
reconnect to a previously connected Access Point (AP) on
startup.

Previously, if Fast Connect failed to connect, any network
socket applications would inevitably fail, as there would have
been no wifi connection.

This patch adds a configurable timeout for the Fast Connect
feature, after which timeout, an error is logged informing
the user to manually reconnect to an AP.

Reconnection is typically accomplished by separately running the
wifi sample shell program.

Fixes: zephyrproject-rtos#11889

Signed-off-by: Gil Pitney <[email protected]>

Author: Gil Pitney

drivers/wifi/simplelink/Kconfig.simplelink

@@ -42,4 +42,13 @@ config WIFI_SIMPLELINK_MAX_SCAN_RETRIES
 	 The number of times, separated by a one second interval, to retry
 	 a request for the network list.
 
+config WIFI_SIMPLELINK_FAST_CONNECT_TIMEOUT
+	int "Time (in seconds) to wait for fast connect on startup"
+	default 7
+	help
+	 SimpleLink uses the "FastConnect" feature to reconnect to the
+	 previously connected AP on startup. Should the WiFi connection
+	 timeout, the SimpleLink driver will fail to initialize,
+	 and LOG an error.
+
 endif # WIFI_SIMPLELINK

drivers/wifi/simplelink/simplelink.c

@@ -22,6 +22,7 @@ LOG_MODULE_REGISTER(LOG_MODULE_NAME);
 #include "simplelink_sockets.h"
 
 #define SCAN_RETRY_DELAY 2000  /* ms */
+#define FC_TIMEOUT K_SECONDS(CONFIG_WIFI_SIMPLELINK_FAST_CONNECT_TIMEOUT)
 
 struct simplelink_data {
 	struct net_if *iface;
@@ -32,9 +33,11 @@ struct simplelink_data {
 	scan_result_cb_t cb;
 	int num_results_or_err;
 	int scan_retries;
+	bool initialized;
 };
 
 static struct simplelink_data simplelink_data;
+static K_SEM_DEFINE(ip_acquired, 0, 1);
 
 /* Handle connection events from the SimpleLink Event Handlers: */
 static void simplelink_wifi_cb(u32_t event, struct sl_connect_state *conn)
@@ -68,6 +71,11 @@ static void simplelink_wifi_cb(u32_t event, struct sl_connect_state *conn)
 		net_if_ipv4_set_gw(simplelink_data.iface, &gwaddr);
 		net_if_ipv4_addr_add(simplelink_data.iface, &addr,
 				     NET_ADDR_DHCP, 0);
+
+		if (!simplelink_data.initialized) {
+			simplelink_data.initialized = true;
+			k_sem_give(&ip_acquired);
+		}
 		break;
 
 	default:
@@ -203,13 +211,23 @@ static void simplelink_iface_init(struct net_if *iface)
 
 	simplelink_data.iface = iface;
 
+	/* Direct socket offload used instead of net offload: */
+	iface->if_dev->offload = &simplelink_offload;
+
 	/* Initialize and configure NWP to defaults: */
 	ret = _simplelink_init(simplelink_wifi_cb);
 	if (ret) {
 		LOG_ERR("_simplelink_init failed!");
 		return;
 	}
 
+	ret = k_sem_take(&ip_acquired, FC_TIMEOUT);
+	if (ret < 0) {
+		simplelink_data.initialized = false;
+		LOG_ERR("FastConnect timed out connecting to previous AP.");
+		LOG_ERR("Please re-establish WiFi connection.");
+	}
+
 	/* Grab our MAC address: */
 	_simplelink_get_mac(simplelink_data.mac);
 
@@ -223,9 +241,6 @@ static void simplelink_iface_init(struct net_if *iface)
 			     sizeof(simplelink_data.mac),
 			     NET_LINK_ETHERNET);
 
-	/* Direct socket offload used instead of net offload: */
-	iface->if_dev->offload = &simplelink_offload;
-
 #ifdef CONFIG_NET_SOCKETS_OFFLOAD
 	/* Direct socket offload: */
 	socket_offload_register(&simplelink_ops);