drivers: wifi: Add support for keepalive

To handle interoperability issue with few APs, add a feature to keep
sending keepalive frames periodically to avoid AP disconnecting the STA.

This is disabled by default to avoid unnecessary power consumption as
it's only seen with few old APs.

Signed-off-by: Chaitanya Tata <[email protected]>

drivers/wifi/nrfwifi/CMakeLists.txt

@@ -289,6 +289,14 @@ zephyr_compile_definitions_ifdef(CONFIG_NRF_WIFI_MGMT_BUFF_OFFLOAD
   -DNRF_WIFI_MGMT_BUFF_OFFLOAD
 )
 
+zephyr_compile_definitions_ifdef(CONFIG_NRF_WIFI_FEAT_KEEPALIVE
+  -DNRF_WIFI_FEAT_KEEPALIVE
+)
+
+zephyr_compile_definitions_ifdef(CONFIG_NRF_WIFI_FEAT_KEEPALIVE
+  -DNRF_WIFI_KEEPALIVE_PERIOD_S=${CONFIG_NRF_WIFI_KEEPALIVE_PERIOD_S}
+)
+
 zephyr_compile_definitions(
   -DNRF70_RX_NUM_BUFS=${CONFIG_NRF70_RX_NUM_BUFS}
   -DNRF70_MAX_TX_TOKENS=${CONFIG_NRF70_MAX_TX_TOKENS}

drivers/wifi/nrfwifi/Kconfig.nrfwifi

@@ -777,4 +777,22 @@ config NRF_WIFI_MGMT_BUFF_OFFLOAD
 	  having to exchange commands and events for every management packet even if it is
 	  consumed by UMAC.
 
+config NRF_WIFI_FEAT_KEEPALIVE
+	bool "Wi-Fi keepalive feature for connection maintenance"
+	depends on NRF70_STA_MODE
+	help
+	  Enable Wi-Fi keepalive feature to keep the connection alive by sending
+	  keepalive packets to the AP. Primarily intended to interoperate with APs
+	  that disconnect idle clients without any explicit checks. Slightly increases
+	  power consumption.
+
+if NRF_WIFI_FEAT_KEEPALIVE
+config NRF_WIFI_KEEPALIVE_PERIOD_S
+	int "Keepalive period in seconds"
+	range 30 3600
+	default 60
+	help
+	  Keepalive period in seconds to send keepalive packets to the AP.
+endif
+
 endif # WIFI_NRF70