esp32: Add support for espnow based pktradio

Espnow is a connectionless WiFi communication protocol that can be used
to exchange information between esp nodes.

A espnow pktradio driver is proposed that allows building a 6lowpan
network of nodes.

The driver has been evaluated using udpclient & server running on
different devices.

Solves #15347

Signed-off-by: Laczen JMS <laczenjms@gmail.com>

arch/xtensa/src/esp32/Kconfig

@@ -745,6 +745,108 @@ config ESP32_WIRELESS
 	---help---
 		Enable Wireless support
 
+config ESP32_ESPNOW_PKTRADIO
+	bool "ESPNOW packet radio support"
+	select ESP32_WIRELESS
+	depends on WIRELESS_PKTRADIO
+	default n
+	---help---
+		Enable using espnow for packet radio
+
+if ESP32_ESPNOW_PKTRADIO
+
+config ESP32_ESPNOW_PKTRADIO_FRAMELEN
+	int "ESPNOW frame length"
+	range 127 250
+	default 196
+	---help---
+		Frame size used for espnow transmitions. Ensure that this is
+		set equal for all nodes.
+
+config ESP32_ESPNOW_PKTRADIO_PANID
+	hex "ESPNOW node panid"
+	range 0x0 0xffff
+	default 0x0
+	---help---
+		PANID for espnow packet radio
+
+if PKTRADIO_ADDRLEN = 1
+
+config ESP32_ESPNOW_PKTRADIO_NODE_ADDR_0
+	hex "ESPNOW node address"
+	range 0x0 0xff
+	default 0x0
+	---help---
+		Node address for espnow packet radio
+
+endif #PKTRADIO_ADDRLEN = 1
+
+if PKTRADIO_ADDRLEN > 1
+
+config ESP32_ESPNOW_PKTRADIO_NODE_ADDR_0
+	hex "ESPNOW node address[0]"
+	range 0x0 0xff
+	default 0x0
+	---help---
+		Node address for espnow packet radio
+
+config ESP32_ESPNOW_PKTRADIO_NODE_ADDR_1
+	hex "ESPNOW node address[1]"
+	range 0x0 0xff
+	default 0x0
+	---help---
+		Node address for espnow packet radio
+
+if PKTRADIO_ADDRLEN > 2
+
+config ESP32_ESPNOW_PKTRADIO_NODE_ADDR_2
+	hex "ESPNOW node address[2]"
+	range 0x0 0xff
+	default 0x0
+	---help---
+		Node address for espnow packet radio
+
+config ESP32_ESPNOW_PKTRADIO_NODE_ADDR_3
+	hex "ESPNOW node address[3]"
+	range 0x0 0xff
+	default 0x0
+	---help---
+		Node address for espnow packet radio
+
+config ESP32_ESPNOW_PKTRADIO_NODE_ADDR_4
+	hex "ESPNOW node address[4]"
+	range 0x0 0xff
+	default 0x0
+	---help---
+		Node address for espnow packet radio
+
+config ESP32_ESPNOW_PKTRADIO_NODE_ADDR_5
+	hex "ESPNOW node address[5]"
+	range 0x0 0xff
+	default 0x0
+	---help---
+		Node address for espnow packet radio
+
+config ESP32_ESPNOW_PKTRADIO_NODE_ADDR_6
+	hex "ESPNOW node address[6]"
+	range 0x0 0xff
+	default 0x0
+	---help---
+		Node address for espnow packet radio
+
+config ESP32_ESPNOW_PKTRADIO_NODE_ADDR_7
+	hex "ESPNOW node address[7]"
+	range 0x0 0xff
+	default 0x0
+	---help---
+		Node address for espnow packet radio
+
+endif #PKTRADIO_ADDRLEN > 2
+
+endif #PKTRADIO_ADDRLEN > 1
+
+endif #ESP32_ESPNOW_PKTRADIO
+
 config ESP32_WIFI
 	bool "Wi-Fi"
 	default n

arch/xtensa/src/esp32/Wireless.mk

@@ -43,6 +43,11 @@ ifeq ($(CONFIG_ESP32_WIFI),y)
 CHIP_CSRCS += esp32_wlan.c esp32_wifi_utils.c esp32_wifi_adapter.c
 EXTRA_LIBS += -lcore -lnet80211 -lpp
 
+ifeq ($(CONFIG_ESP32_ESPNOW_PKTRADIO),y)
+CHIP_CSRCS += esp32_espnow_pktradio.c
+EXTRA_LIBS += -lespnow
+endif
+
 ifeq ($(CONFIG_WPA_WAPI_PSK),y)
 EXTRA_LIBS += -lwapi
 endif

arch/xtensa/src/esp32/esp32_espnow_pktradio.h

@@ -0,0 +1,77 @@
+/****************************************************************************
+ * arch/xtensa/src/esp32/esp32_espnow_pktradio.h
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.  The
+ * ASF licenses this file to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the
+ * License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ *
+ ****************************************************************************/
+
+#ifndef __ARCH_XTENSA_SRC_COMMON_ESPRESSIF_ESP_ESPNOW_PKTRADIO_H
+#define __ARCH_XTENSA_SRC_COMMON_ESPRESSIF_ESP_ESPNOW_PKTRADIO_H
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#ifndef __ASSEMBLY__
+
+#undef EXTERN
+#if defined(__cplusplus)
+#define EXTERN extern "C"
+extern "C"
+{
+#else
+#define EXTERN extern
+#endif
+
+#ifdef CONFIG_ESP32_ESPNOW_PKTRADIO
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Function Prototypes
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: pktradio_espnow
+ *
+ * Description:
+ *   Initialize and register the 6LoWPAN over espnow MAC network driver.
+ *
+ * Input Parameters:
+ *   None
+ *
+ * Returned Value:
+ *   OK on success; Negated errno on failure.
+ *
+ * Assumptions:
+ *
+ ****************************************************************************/
+
+int pktradio_espnow(void);
+#endif /* CONFIG_ESP32_ESPNOW_PKTRADIO */
+
+#ifdef __cplusplus
+}
+#endif
+#undef EXTERN
+
+#endif /* __ASSEMBLY__ */
+#endif /* __ARCH_XTENSA_SRC_COMMON_ESPRESSIF_ESP_ESPNOW_PKTRADIO_H */

boards/xtensa/esp32/esp32-devkitc/src/esp32_bringup.c

@@ -179,6 +179,10 @@
 #  include "espressif/esp_nxdiag.h"
 #endif
 
+#ifdef CONFIG_ESP32_ESPNOW_PKTRADIO
+#  include "esp32_espnow_pktradio.h"
+#endif
+
 #include "esp32-devkitc.h"
 
 /****************************************************************************
@@ -362,6 +366,15 @@ int esp32_bringup(void)
     }
 #endif
 
+#ifdef CONFIG_ESP32_ESPNOW_PKTRADIO
+  ret = pktradio_espnow();
+  if (ret < 0)
+    {
+      syslog(LOG_ERR, "ERROR: Failed to initialize ESPNOW pktradio=%d\n",
+             ret);
+    }
+#endif
+
 #ifdef CONFIG_ESP32_OPENETH
   ret = esp_openeth_initialize();
   if (ret < 0)