address review; fix STM; add limitation for STM

Author: dhalbert

ports/espressif/supervisor/usb_serial_jtag.c

@@ -122,7 +122,7 @@ char usb_serial_jtag_read_char(void) {
 }
 
 uint32_t usb_serial_jtag_bytes_available(void) {
-    return ringbuf_num_filled(&ringbuf) || usb_serial_jtag_ll_rxfifo_data_available();
+    return ringbuf_num_filled(&ringbuf) + usb_serial_jtag_ll_rxfifo_data_available();
 }
 
 void usb_serial_jtag_write(const char *text, uint32_t length) {

ports/silabs/supervisor/serial.c

@@ -141,9 +141,8 @@ char port_serial_read(void) {
     return (char)data;
 }
 
-// Checking ring buffer haves bytes available or not
-bool port_serial_bytes_available(void) {
-    return ringbuf_num_filled(&con_uart_rx_ringbuf) > 0 ? true : false;
+uint32_t port_serial_bytes_available(void) {
+    return ringbuf_num_filled(&con_uart_rx_ringbuf);
 }
 
 // Send n bytes data to serial by EUSART0

ports/stm/supervisor/serial.c

@@ -66,11 +66,12 @@ char port_serial_read(void) {
     #endif
 }
 
-bool port_serial_bytes_available(void) {
+// There is no easy way to find the number of pending characters, so just say there's 1.
+uint32_t port_serial_bytes_available(void) {
     #if CPY_STM32F4
-    return __HAL_UART_GET_FLAG(&huart2, UART_FLAG_RXNE);
+    return __HAL_UART_GET_FLAG(&huart2, UART_FLAG_RXNE) ? 1 : 0;
     #else
-    return false;
+    return 0;
     #endif
 }
 

shared-bindings/supervisor/Runtime.c

@@ -88,9 +88,14 @@ MP_PROPERTY_GETTER(supervisor_runtime_serial_connected_obj,
     (mp_obj_t)&supervisor_runtime_get_serial_connected_obj);
 
 //|     serial_bytes_available: int
-//|     """Returns the number of bytes are available to read
-//|     on the USB serial input.  Allows for polling to see whether
-//|     to call the built-in input() or wait. (read-only)
+//|     """Returns the number of bytes are available to read on the console serial input.
+//|     Multiple console serial inputs may be in use at once, including
+//|     USB, web workflow, BLE workflow, and/or UART.
+//|
+//|     Allows for polling to see whether to call the built-in input() or wait. (read-only)
+//|
+//|     **Limitations**: On STM, UART (not USB) console input can only determine that at least one character
+//|     is available, and so if only the UART console is in use, only ``1`` or ``0`` will be returned.
 //|
 //|     Changed in version 9.1.0: Previously returned only ``True`` or ``False``.
 //|     Since ``0`` acts as ``False``, ``if supervisor.runtime.serial_byes_available:``

supervisor/shared/serial.c

@@ -295,70 +295,45 @@ char serial_read(void) {
 }
 
 uint32_t serial_bytes_available(void) {
+    // There may be multiple serial input channels, so sum the count from all.
+    uint32_t count = 0;
+
     #if CIRCUITPY_USB_VENDOR
     if (tud_vendor_connected()) {
-        uint32_t count = tud_vendor_available();
-        if (count > 0) {
-            return count;
-        }
+        count += tud_vendor_available();
     }
     #endif
 
     #if CIRCUITPY_CONSOLE_UART
-    {
-        uint32_t count = common_hal_busio_uart_rx_characters_available(&console_uart);
-        if (count > 0) {
-            return count;
-        }
-    }
+    count += common_hal_busio_uart_rx_characters_available(&console_uart);
     #endif
 
     #if CIRCUITPY_SERIAL_BLE
-    {
-        uint32_t count = ble_serial_available();
-        if (count > 0) {
-            return count;
-        }
-    }
+    count += ble_serial_available();
     #endif
 
     #if CIRCUITPY_WEB_WORKFLOW
-    {
-        uint32_t count = websocket_available();
-        if (count > 0) {
-            return count;
-        }
-    }
+    count += websocket_available();
     #endif
 
     #if CIRCUITPY_USB_KEYBOARD_WORKFLOW
-    {
-        uint32_t count = usb_keyboard_chars_available();
-        if (count > 0) {
-            return count;
-        }
-    }
+    count += usb_keyboard_chars_available();
     #endif
 
     #if CIRCUITPY_USB_CDC
     if (usb_cdc_console_enabled()) {
-        uint32_t count = tud_cdc_available();
-        if (count > 0) {
-            return count;
-        }
+        count += tud_cdc_available();
     }
     #endif
 
     #if CIRCUITPY_USB
-    {
-        uint32_t count = tud_cdc_available();
-        if (count > 0) {
-            return count;
-        }
-    }
+    count += tud_cdc_available();
     #endif
 
-    return port_serial_bytes_available();
+    // Port-specific serial input.
+    count += port_serial_bytes_available();
+
+    return count;
 }
 
 void serial_write_substring(const char *text, uint32_t length) {