esp32: Add support for USB with CDC ACM.

The REPL will be available on the USB serial port.

Signed-off-by: Damien George <damien@micropython.org>

ports/esp32/boards/sdkconfig.usb

@@ -0,0 +1,4 @@
+CONFIG_USB_ENABLED=y
+CONFIG_USB_CDC_ENABLED=y
+CONFIG_USB_CDC_RX_BUFSIZE=256
+CONFIG_USB_CDC_TX_BUFSIZE=256

ports/esp32/main.c

@@ -55,6 +55,7 @@
 #include "lib/mp-readline/readline.h"
 #include "lib/utils/pyexec.h"
 #include "uart.h"
+#include "usb.h"
 #include "modmachine.h"
 #include "modnetwork.h"
 #include "mpthreadport.h"
@@ -77,7 +78,11 @@ void mp_task(void *pvParameter) {
     #if MICROPY_PY_THREAD
     mp_thread_init(pxTaskGetStackStart(NULL), MP_TASK_STACK_SIZE / sizeof(uintptr_t));
     #endif
+    #if CONFIG_USB_ENABLED
+    usb_init();
+    #else
     uart_init();
+    #endif
     machine_init();
 
     // TODO: CONFIG_SPIRAM_SUPPORT is for 3.3 compatibility, remove after move to 4.0.

ports/esp32/main/CMakeLists.txt

@@ -37,6 +37,7 @@ set(MICROPY_SOURCE_DRIVERS
 set(MICROPY_SOURCE_PORT
     ${PROJECT_DIR}/main.c
     ${PROJECT_DIR}/uart.c
+    ${PROJECT_DIR}/usb.c
     ${PROJECT_DIR}/gccollect.c
     ${PROJECT_DIR}/mphalport.c
     ${PROJECT_DIR}/fatfs_port.c
@@ -126,6 +127,7 @@ if(IDF_TARGET STREQUAL "esp32")
     list(APPEND IDF_COMPONENTS esp32)
 elseif(IDF_TARGET STREQUAL "esp32s2")
     list(APPEND IDF_COMPONENTS esp32s2)
+    list(APPEND IDF_COMPONENTS tinyusb)
 endif()
 
 # Register the main IDF component.
@@ -185,6 +187,10 @@ if(IDF_VERSION_MINOR GREATER_EQUAL 2)
     # so add them explicitly.
     list(APPEND MICROPY_CPP_INC_EXTRA ${IDF_PATH}/components/soc/soc/${IDF_TARGET}/include)
     list(APPEND MICROPY_CPP_INC_EXTRA ${IDF_PATH}/components/soc/soc/include)
+    if(IDF_VERSION_MINOR GREATER_EQUAL 3)
+        list(APPEND MICROPY_CPP_INC_EXTRA ${IDF_PATH}/components/tinyusb/additions/include)
+        list(APPEND MICROPY_CPP_INC_EXTRA ${IDF_PATH}/components/tinyusb/tinyusb/src)
+    endif()
 endif()
 
 # Include the main MicroPython cmake rules.

ports/esp32/mphalport.c

@@ -43,10 +43,11 @@
 #include "lib/timeutils/timeutils.h"
 #include "lib/utils/pyexec.h"
 #include "mphalport.h"
+#include "usb.h"
 
 TaskHandle_t mp_main_task_handle;
 
-STATIC uint8_t stdin_ringbuf_array[256];
+STATIC uint8_t stdin_ringbuf_array[260];
 ringbuf_t stdin_ringbuf = {stdin_ringbuf_array, sizeof(stdin_ringbuf_array), 0, 0};
 
 // Check the ESP-IDF error code and raise an OSError if it's not ESP_OK.
@@ -110,9 +111,13 @@ void mp_hal_stdout_tx_strn(const char *str, uint32_t len) {
     if (release_gil) {
         MP_THREAD_GIL_EXIT();
     }
+    #if CONFIG_USB_ENABLED
+    usb_tx_strn(str, len);
+    #else
     for (uint32_t i = 0; i < len; ++i) {
         uart_tx_one_char(str[i]);
     }
+    #endif
     if (release_gil) {
         MP_THREAD_GIL_ENTER();
     }

ports/esp32/usb.c

@@ -0,0 +1,92 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2021 Damien P. George
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "py/runtime.h"
+#include "py/mphal.h"
+#include "usb.h"
+
+#if CONFIG_USB_ENABLED
+
+#include "tinyusb.h"
+#include "tusb_cdc_acm.h"
+
+#define CDC_ITF TINYUSB_CDC_ACM_0
+
+static uint8_t usb_rx_buf[CONFIG_USB_CDC_RX_BUFSIZE];
+
+static void usb_callback_rx(int itf, cdcacm_event_t *event) {
+    // TODO: what happens if more chars come in during this function, are they lost?
+    for (;;) {
+        size_t len = 0;
+        esp_err_t ret = tinyusb_cdcacm_read(itf, usb_rx_buf, sizeof(usb_rx_buf), &len);
+        if (ret != ESP_OK) {
+            break;
+        }
+        if (len == 0) {
+            break;
+        }
+        for (size_t i = 0; i < len; ++i) {
+            if (usb_rx_buf[i] == mp_interrupt_char) {
+                mp_keyboard_interrupt();
+            } else {
+                ringbuf_put(&stdin_ringbuf, usb_rx_buf[i]);
+            }
+        }
+    }
+}
+
+void usb_init(void) {
+    // Initialise the USB with defaults.
+    tinyusb_config_t tusb_cfg = {0};
+    ESP_ERROR_CHECK(tinyusb_driver_install(&tusb_cfg));
+
+    // Initialise the USB serial interface.
+    tinyusb_config_cdcacm_t amc_cfg = {
+        .usb_dev = TINYUSB_USBDEV_0,
+        .cdc_port = CDC_ITF,
+        .rx_unread_buf_sz = 256,
+        .callback_rx = &usb_callback_rx,
+        .callback_rx_wanted_char = NULL,
+        .callback_line_state_changed = NULL,
+        .callback_line_coding_changed = NULL
+    };
+    ESP_ERROR_CHECK(tusb_cdc_acm_init(&amc_cfg));
+}
+
+void usb_tx_strn(const char *str, size_t len) {
+    while (len) {
+        size_t l = len;
+        if (l > CONFIG_USB_CDC_TX_BUFSIZE) {
+            l = CONFIG_USB_CDC_TX_BUFSIZE;
+        }
+        tinyusb_cdcacm_write_queue(CDC_ITF, (uint8_t *)str, l);
+        tinyusb_cdcacm_write_flush(CDC_ITF, pdMS_TO_TICKS(1000));
+        str += l;
+        len -= l;
+    }
+}
+
+#endif // CONFIG_USB_ENABLED

ports/esp32/usb.h

@@ -0,0 +1,32 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2021 Damien P. George
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+#ifndef MICROPY_INCLUDED_ESP32_USB_H
+#define MICROPY_INCLUDED_ESP32_USB_H
+
+void usb_init(void);
+void usb_tx_strn(const char *str, size_t len);
+
+#endif // MICROPY_INCLUDED_ESP32_USB_H