driver: wifi: Add inventek es-WiFi driver

es-WiFi compatible modules use IWIN AT command set.
This driver is split into several layers:
- bus layer: interface to transmit AT commands (SPI, USB, UART...)
- core layer: es-WiFi module management (state, scan...)
- offload layer: TCP/IP offload operations (connect, listen...)

This driver has been tested with stm32l4 disco iot board
(disco_l475_iot1) and the wifi sample:

$ select wifi
$ scan
$ connect "CISCO" 5 password
$ select net
$ tcp connect 192.168.1.21 4242
$ tcp send HelloWorld!

Signed-off-by: Loic Poulain <[email protected]>

Author: Loic Poulain

drivers/wifi/CMakeLists.txt

@@ -1,2 +1,3 @@
 add_subdirectory_ifdef(CONFIG_WIFI_WINC1500	winc1500)
 add_subdirectory_ifdef(CONFIG_WIFI_SIMPLELINK	simplelink)
+add_subdirectory_ifdef(CONFIG_WIFI_ESWIFI	eswifi)

drivers/wifi/Kconfig

@@ -35,5 +35,6 @@ config WIFI_OFFLOAD
 
 source "drivers/wifi/winc1500/Kconfig.winc1500"
 source "drivers/wifi/simplelink/Kconfig.simplelink"
+source "drivers/wifi/eswifi/Kconfig.eswifi"
 
 endif # WIFI

drivers/wifi/eswifi/CMakeLists.txt

@@ -0,0 +1,14 @@
+if(CONFIG_WIFI_ESWIFI)
+  zephyr_include_directories(./)
+
+  zephyr_library_include_directories(
+  # IP headers
+  ${ZEPHYR_BASE}/subsys/net/ip
+  )
+
+  zephyr_sources(
+    eswifi_core.c
+    eswifi_bus_spi.c
+    eswifi_offload.c
+    )
+endif()

drivers/wifi/eswifi/Kconfig.eswifi

@@ -0,0 +1,28 @@
+# Kconfig - es-WiFi driver options
+
+#
+# Copyright (c) 2018 Linaro
+#
+# SPDX-License-Identifier: Apache-2.0
+#
+
+menuconfig WIFI_ESWIFI
+	bool "Inventek eS-WiFi support"
+	depends on WIFI
+	select NET_L2_WIFI_MGMT
+	select WIFI_OFFLOAD
+
+if WIFI_ESWIFI
+
+config WIFI_ESWIFI_NAME
+	string "Driver name"
+	default "ESWIFI"
+
+config WIFI_ESWIFI_THREAD_PRIO
+	int "esWiFi threads priority"
+	default 2
+	help
+	  This option sets the priority of the esWiFi threads.
+	  Do not touch it unless you know what you are doing.
+
+endif

drivers/wifi/eswifi/eswifi.h

@@ -0,0 +1,105 @@
+/**
+ * Copyright (c) 2018 Linaro
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#ifndef ZEPHYR_DRIVERS_WIFI_ESWIFI_ESWIFI_H_
+#define ZEPHYR_DRIVERS_WIFI_ESWIFI_ESWIFI_H_
+
+#include <zephyr.h>
+#include <kernel.h>
+
+#include <net/wifi_mgmt.h>
+
+#include "eswifi_offload.h"
+
+#define MAX_DATA_SIZE 1600
+
+#define AT_OK_STR "\r\nOK\r\n> "
+#define AT_OK_STR_LEN 8
+#define AT_RSP_DELIMITER "\r\n"
+#define AT_RSP_DELIMITER_LEN 2
+
+struct device *uarthost;
+
+struct eswifi_gpio {
+	struct device *dev;
+	unsigned int pin;
+};
+
+enum eswifi_security_type {
+	ESWIFI_SEC_OPEN,
+	ESWIFI_SEC_WEP,
+	ESWIFI_SEC_WPA,
+	ESWIFI_SEC_WPA2_AES,
+	ESWIFI_SEC_WPA2_MIXED,
+	ESWIFI_SEC_MAX
+};
+
+enum eswifi_request {
+	ESWIFI_REQ_SCAN,
+	ESWIFI_REQ_CONNECT,
+	ESWIFI_REQ_DISCONNECT,
+	ESWIFI_REQ_NONE
+};
+
+enum eswifi_role {
+	ESWIFI_ROLE_CLIENT,
+	ESWIFI_ROLE_AP,
+};
+
+struct eswifi_sta {
+	char ssid[WIFI_SSID_MAX_LEN + 1];
+	enum eswifi_security_type security;
+	char pass[65];
+	bool connected;
+};
+
+struct eswifi_bus_ops;
+
+struct eswifi_dev {
+	struct net_if *iface;
+	struct eswifi_bus_ops *bus;
+	struct eswifi_gpio resetn;
+	struct eswifi_gpio wakeup;
+	scan_result_cb_t scan_cb;
+	struct k_work_q work_q;
+	struct k_work request_work;
+	struct eswifi_sta sta;
+	enum eswifi_request req;
+	enum eswifi_role role;
+	char buf[MAX_DATA_SIZE];
+	struct k_mutex mutex;
+	void *bus_data;
+	struct eswifi_off_socket socket[ESWIFI_OFFLOAD_MAX_SOCKETS];
+};
+
+struct eswifi_bus_ops {
+	int (*init)(struct eswifi_dev *eswifi);
+	int (*request)(struct eswifi_dev *eswifi, char *cmd, size_t clen,
+		       char *rsp, size_t rlen);
+};
+
+static inline int eswifi_request(struct eswifi_dev *eswifi, char *cmd,
+				 size_t clen, char *rsp, size_t rlen)
+{
+	return eswifi->bus->request(eswifi, cmd, clen, rsp, rlen);
+}
+
+static inline void eswifi_lock(struct eswifi_dev *eswifi)
+{
+	k_mutex_lock(&eswifi->mutex, K_FOREVER);
+}
+
+static inline void eswifi_unlock(struct eswifi_dev *eswifi)
+{
+	k_mutex_unlock(&eswifi->mutex);
+}
+
+struct eswifi_bus_ops eswifi_bus_ops_spi;
+int eswifi_offload_init(struct eswifi_dev *eswifi);
+struct eswifi_dev *eswifi_by_iface_idx(u8_t iface);
+bool eswifi_is_buf_at_ok(char *str);
+
+#endif