feat(openthread): support rcp based on USB Serial JTAG

Author: nagisa

components/openthread/CMakeLists.txt

@@ -171,7 +171,7 @@ if(CONFIG_OPENTHREAD_ENABLED)
     if(CONFIG_OPENTHREAD_NCP_VENDOR_HOOK)
         list(APPEND src_dirs
             "src/ncp")
-        if(CONFIG_OPENTHREAD_RCP_UART)
+        if(CONFIG_OPENTHREAD_RCP_UART OR CONFIG_OPENTHREAD_RCP_USB_SERIAL_JTAG)
             list(APPEND exclude_srcs
                 "src/ncp/esp_openthread_ncp_spi.cpp")
         elseif(CONFIG_OPENTHREAD_RCP_SPI)

components/openthread/Kconfig

@@ -196,6 +196,12 @@ menu "OpenThread"
                     select GPIO_CTRL_FUNC_IN_IRAM
                     help
                         Select this to enable SPI connection to host.
+
+                config OPENTHREAD_RCP_USB_SERIAL_JTAG
+                    depends on ESP_CONSOLE_SECONDARY_USB_SERIAL_JTAG && !OPENTHREAD_CONSOLE_TYPE_USB_SERIAL_JTAG
+                    bool "USB RCP"
+                    help
+                        Select this to enable connection to host over USB JTAG serial.
             endchoice
 
             config OPENTHREAD_NCP_VENDOR_HOOK

components/openthread/include/esp_openthread_types.h

@@ -150,6 +150,7 @@ typedef enum {
     HOST_CONNECTION_MODE_CLI_USB,        /*!< CLI USB connection to the host */
     HOST_CONNECTION_MODE_RCP_UART,       /*!< RCP UART connection to the host */
     HOST_CONNECTION_MODE_RCP_SPI,        /*!< RCP SPI connection to the host */
+    HOST_CONNECTION_MODE_RCP_USB,       /*!<  RCP USB Serial JTAG connection to the host */
     HOST_CONNECTION_MODE_MAX,            /*!< Using for parameter check */
 } esp_openthread_host_connection_mode_t;
 

components/openthread/private_include/esp_openthread_uart.h

@@ -1,5 +1,5 @@
 /*
- * SPDX-FileCopyrightText: 2021-2023 Espressif Systems (Shanghai) CO LTD
+ * SPDX-FileCopyrightText: 2021-2025 Espressif Systems (Shanghai) CO LTD
  *
  * SPDX-License-Identifier: Apache-2.0
  */
@@ -64,6 +64,18 @@ esp_err_t esp_openthread_host_cli_usb_init(const esp_openthread_platform_config_
  */
 esp_err_t esp_openthread_host_rcp_uart_init(const esp_openthread_platform_config_t *config);
 
+/**
+ * @brief  Initializes the RCP USB for OpenThread host connection.
+ *
+ * @param[in]   config  The platform configuration.
+ *
+ * @return
+ *      - ESP_OK on success
+ *      - ESP_ERROR on failure
+ *
+ */
+esp_err_t esp_openthread_host_rcp_usb_init(const esp_openthread_platform_config_t *config);
+
 /**
  * @brief  Deintializes the uart for OpenThread host connection.
  *

components/openthread/private_include/openthread-core-esp32x-radio-config.h

@@ -91,7 +91,7 @@
 #ifdef OPENTHREAD_CONFIG_NCP_HDLC_ENABLE
 #error `OPENTHREAD_CONFIG_NCP_HDLC_ENABLE` is redefined.
 #endif
-#define OPENTHREAD_CONFIG_NCP_HDLC_ENABLE CONFIG_OPENTHREAD_RCP_UART
+#define OPENTHREAD_CONFIG_NCP_HDLC_ENABLE (CONFIG_OPENTHREAD_RCP_UART || CONFIG_OPENTHREAD_RCP_USB_SERIAL_JTAG)
 
 /**
  * @def OPENTHREAD_LIB_SPINEL_RX_FRAME_BUFFER_SIZE

components/openthread/src/esp_openthread_platform.cpp

@@ -1,5 +1,5 @@
 /*
- * SPDX-FileCopyrightText: 2021-2024 Espressif Systems (Shanghai) CO LTD
+ * SPDX-FileCopyrightText: 2021-2025 Espressif Systems (Shanghai) CO LTD
  *
  * SPDX-License-Identifier: Apache-2.0
  */
@@ -106,6 +106,12 @@ static esp_err_t esp_openthread_host_interface_init(const esp_openthread_platfor
                           "esp_openthread_host_rcp_uart_init failed");
         break;
 #endif
+#if CONFIG_OPENTHREAD_RCP_USB_SERIAL_JTAG
+    case HOST_CONNECTION_MODE_RCP_USB:
+        ESP_RETURN_ON_ERROR(esp_openthread_host_rcp_usb_init(config), OT_PLAT_LOG_TAG,
+                          "esp_openthread_host_rcp_usb_init failed");
+        break;
+#endif
 #if CONFIG_OPENTHREAD_CONSOLE_TYPE_UART
     case HOST_CONNECTION_MODE_CLI_UART:
         ESP_RETURN_ON_ERROR(esp_openthread_host_cli_uart_init(config), OT_PLAT_LOG_TAG,

components/openthread/src/ncp/esp_openthread_ncp.cpp

@@ -13,11 +13,11 @@
 #include "esp_coex_i154.h"
 #endif
 
-#if CONFIG_OPENTHREAD_RCP_UART
+#if (CONFIG_OPENTHREAD_RCP_UART || CONFIG_OPENTHREAD_RCP_USB_SERIAL_JTAG)
 #include "utils/uart.h"
 #endif
 
-#if CONFIG_OPENTHREAD_RCP_UART
+#if (CONFIG_OPENTHREAD_RCP_UART || CONFIG_OPENTHREAD_RCP_USB_SERIAL_JTAG)
 extern "C" {
     static int NcpSend(const uint8_t *aBuf, uint16_t aBufLength)
     {

components/openthread/src/port/esp_openthread_uart.c

@@ -31,7 +31,7 @@ static int s_uart_fd;
 static uint8_t s_uart_buffer[ESP_OPENTHREAD_UART_BUFFER_SIZE];
 static const char *uart_workflow = "uart";
 
-#if (CONFIG_OPENTHREAD_CLI || (CONFIG_OPENTHREAD_RADIO && CONFIG_OPENTHREAD_RCP_UART))
+#if (CONFIG_OPENTHREAD_CLI || (CONFIG_OPENTHREAD_RADIO && (CONFIG_OPENTHREAD_RCP_UART || CONFIG_OPENTHREAD_RCP_USB_SERIAL_JTAG)))
 otError otPlatUartEnable(void)
 {
     return OT_ERROR_NONE;
@@ -116,6 +116,7 @@ esp_err_t esp_openthread_host_cli_uart_init(const esp_openthread_platform_config
 }
 #endif
 
+#if CONFIG_OPENTHREAD_RCP_UART
 esp_err_t esp_openthread_host_rcp_uart_init(const esp_openthread_platform_config_t *config)
 {
     esp_err_t ret = ESP_OK;
@@ -135,6 +136,28 @@ esp_err_t esp_openthread_host_rcp_uart_init(const esp_openthread_platform_config
 
     return ret;
 }
+#endif
+
+#if CONFIG_OPENTHREAD_RCP_USB_SERIAL_JTAG
+esp_err_t esp_openthread_host_rcp_usb_init(const esp_openthread_platform_config_t *config)
+{
+    esp_err_t ret = ESP_OK;
+
+    usb_serial_jtag_vfs_set_rx_line_endings(ESP_LINE_ENDINGS_LF);
+    usb_serial_jtag_vfs_set_tx_line_endings(ESP_LINE_ENDINGS_LF);
+
+    ESP_ERROR_CHECK(usb_serial_jtag_driver_install((usb_serial_jtag_driver_config_t *)&config->host_config.host_usb_config));
+    ESP_ERROR_CHECK(usb_serial_jtag_vfs_register());
+    usb_serial_jtag_vfs_use_driver();
+
+    s_uart_fd = open("/dev/usbserjtag", O_RDWR | O_NONBLOCK);
+    ESP_RETURN_ON_FALSE(s_uart_fd >= 0, ESP_FAIL, OT_PLAT_LOG_TAG, "open usbserjtag failed");
+    ret = esp_openthread_platform_workflow_register(&esp_openthread_uart_update, &esp_openthread_uart_process,
+                                                    uart_workflow);
+
+    return ret;
+}
+#endif
 
 void esp_openthread_uart_deinit()
 {
@@ -159,7 +182,7 @@ esp_err_t esp_openthread_uart_process(otInstance *instance, const esp_openthread
     int rval = read(s_uart_fd, s_uart_buffer, sizeof(s_uart_buffer));
 
     if (rval > 0) {
-#if (CONFIG_OPENTHREAD_CLI || (CONFIG_OPENTHREAD_RADIO && CONFIG_OPENTHREAD_RCP_UART))
+#if (CONFIG_OPENTHREAD_CLI || (CONFIG_OPENTHREAD_RADIO && (CONFIG_OPENTHREAD_RCP_UART || CONFIG_OPENTHREAD_RCP_USB_SERIAL_JTAG)))
         otPlatUartReceived(s_uart_buffer, (uint16_t)rval);
 #endif
     } else if (rval < 0) {

examples/openthread/ot_rcp/main/esp_ot_config.h

@@ -1,5 +1,5 @@
 /*
- * SPDX-FileCopyrightText: 2021-2023 Espressif Systems (Shanghai) CO LTD
+ * SPDX-FileCopyrightText: 2021-2025 Espressif Systems (Shanghai) CO LTD
  *
  * SPDX-License-Identifier: CC0-1.0
  *
@@ -52,7 +52,7 @@
             .tx_pin = OPENTHREAD_RCP_UART_TX_PIN,               \
         },                                                      \
     }
-#else // CONFIG_OPENTHREAD_RCP_SPI
+#elif CONFIG_OPENTHREAD_RCP_SPI // CONFIG_OPENTHREAD_RCP_SPI
 #define ESP_OPENTHREAD_DEFAULT_HOST_CONFIG()                    \
     {                                                           \
         .host_connection_mode = HOST_CONNECTION_MODE_RCP_SPI,   \
@@ -75,6 +75,12 @@
             .intr_pin = 9,                                      \
         },                                                      \
     }
+#else // CONFIG_OPENTHREAD_RCP_USB_SERIAL_JTAG
+#define ESP_OPENTHREAD_DEFAULT_HOST_CONFIG()                        \
+    {                                                               \
+        .host_connection_mode = HOST_CONNECTION_MODE_RCP_USB,       \
+        .host_usb_config = USB_SERIAL_JTAG_DRIVER_CONFIG_DEFAULT(), \
+    }
 #endif
 
 #define ESP_OPENTHREAD_DEFAULT_PORT_CONFIG()    \

examples/openthread/ot_rcp/sdkconfig.ci.rcp_usb

@@ -0,0 +1 @@
+CONFIG_OPENTHREAD_RCP_USB_SERIAL_JTAG=y