esp32/uart: Correctly init low-level UART driver for REPL.

uart_driver_install() needs to be called to set up the UART correctly.

ports/esp32/main.c

@@ -93,7 +93,7 @@ void mp_task(void *pvParameter) {
     #elif CONFIG_ESP_CONSOLE_USB_SERIAL_JTAG
     usb_serial_jtag_init();
     #else
-    uart_init();
+    uart_stdout_init();
     #endif
     machine_init();
 

ports/esp32/mphalport.c

@@ -33,16 +33,6 @@
 #include "freertos/FreeRTOS.h"
 #include "freertos/task.h"
 
-#if CONFIG_IDF_TARGET_ESP32
-#include "esp32/rom/uart.h"
-#elif CONFIG_IDF_TARGET_ESP32C3
-#include "esp32c3/rom/uart.h"
-#elif CONFIG_IDF_TARGET_ESP32S2
-#include "esp32s2/rom/uart.h"
-#elif CONFIG_IDF_TARGET_ESP32S3
-#include "esp32s3/rom/uart.h"
-#endif
-
 #include "py/obj.h"
 #include "py/objstr.h"
 #include "py/stream.h"
@@ -54,6 +44,7 @@
 #include "mphalport.h"
 #include "usb.h"
 #include "usb_serial_jtag.h"
+#include "uart.h"
 
 TaskHandle_t mp_main_task_handle;
 
@@ -122,9 +113,7 @@ void mp_hal_stdout_tx_strn(const char *str, size_t len) {
     #elif CONFIG_ESP_CONSOLE_USB_SERIAL_JTAG
     usb_serial_jtag_tx_strn(str, len);
     #else
-    for (uint32_t i = 0; i < len; ++i) {
-        uart_tx_one_char(str[i]);
-    }
+    uart_stdout_tx_strn(str, len);
     #endif
     if (release_gil) {
         MP_THREAD_GIL_ENTER();

ports/esp32/uart.c

@@ -33,13 +33,56 @@
 
 #include "py/runtime.h"
 #include "py/mphal.h"
+#include "uart.h"
+
+#ifndef MICROPY_HW_UART_REPL
+#define MICROPY_HW_UART_REPL (UART_NUM_0)
+#endif
+
+#ifndef MICROPY_HW_UART_REPL_BAUD
+#define MICROPY_HW_UART_REPL_BAUD (115200)
+#endif
 
 STATIC void uart_irq_handler(void *arg);
 
-void uart_init(void) {
+void uart_stdout_init(void) {
+    uart_config_t uartcfg = {
+        .baud_rate = MICROPY_HW_UART_REPL_BAUD,
+        .data_bits = UART_DATA_8_BITS,
+        .parity = UART_PARITY_DISABLE,
+        .stop_bits = UART_STOP_BITS_1,
+        .flow_ctrl = UART_HW_FLOWCTRL_DISABLE,
+        .rx_flow_ctrl_thresh = 0
+    };
+    uart_param_config(MICROPY_HW_UART_REPL, &uartcfg);
+
+    const uint32_t rxbuf = 129; // IDF requires > 128 min
+    const uint32_t txbuf = 0;
+
+    uart_driver_install(MICROPY_HW_UART_REPL, rxbuf, txbuf, 0, NULL, 0);
+
     uart_isr_handle_t handle;
-    uart_isr_register(UART_NUM_0, uart_irq_handler, NULL, ESP_INTR_FLAG_LOWMED | ESP_INTR_FLAG_IRAM, &handle);
-    uart_enable_rx_intr(UART_NUM_0);
+    uart_isr_free(MICROPY_HW_UART_REPL);
+    uart_isr_register(MICROPY_HW_UART_REPL, uart_irq_handler, NULL, ESP_INTR_FLAG_LOWMED | ESP_INTR_FLAG_IRAM, &handle);
+    uart_enable_rx_intr(MICROPY_HW_UART_REPL);
+}
+
+int uart_stdout_tx_strn(const char *str, size_t len) {
+    size_t remaining = len;
+    // TODO add a timeout
+    for (;;) {
+        int ret = uart_tx_chars(MICROPY_HW_UART_REPL, str, remaining);
+        if (ret == -1) {
+            return -1;
+        }
+        remaining -= ret;
+        if (remaining <= 0) {
+            break;
+        }
+        str += ret;
+        ulTaskNotifyTake(pdFALSE, 1);
+    }
+    return len - remaining;
 }
 
 // all code executed in ISR must be in IRAM, and any const data must be in DRAM

ports/esp32/uart.h

@@ -28,6 +28,7 @@
 #ifndef MICROPY_INCLUDED_ESP32_UART_H
 #define MICROPY_INCLUDED_ESP32_UART_H
 
-void uart_init(void);
+void uart_stdout_init(void);
+int uart_stdout_tx_strn(const char *str, size_t len);
 
 #endif // MICROPY_INCLUDED_ESP32_UART_H