stm32/mphalport: Improve efficiency of mp_hal_stdout_tx_strn_cooked.

Also simplifies the code by removing the specialised (and inefficient)
cooked functions from UART and USB_VCP.

ports/stm32/mphalport.c

@@ -58,13 +58,23 @@ void mp_hal_stdout_tx_strn(const char *str, size_t len) {
     }
 }
 
+// Efficiently convert "\n" to "\r\n"
 void mp_hal_stdout_tx_strn_cooked(const char *str, size_t len) {
-    // send stdout to UART and USB CDC VCP
+    const char *last = str;
-    if (MP_STATE_PORT(pyb_stdio_uart) != NULL) {
+    while (len--) {
-        uart_tx_strn_cooked(MP_STATE_PORT(pyb_stdio_uart), str, len);
+        if (*str == '\n') {
+            if (str > last) {
+                mp_hal_stdout_tx_strn(last, str - last);
+            }
+            mp_hal_stdout_tx_strn("\r\n", 2);
+            ++str;
+            last = str;
+        } else {
+            ++str;
+        }
     }
-    if (usb_vcp_is_enabled()) {
+    if (str > last) {
-        usb_vcp_send_strn_cooked(str, len);
+        mp_hal_stdout_tx_strn(last, str - last);
     }
 }
 

ports/stm32/uart.c

@@ -452,26 +452,11 @@ STATIC size_t uart_tx_data(pyb_uart_obj_t *self, const void *src_in, size_t num_
     return num_tx;
 }
 
-STATIC void uart_tx_char(pyb_uart_obj_t *uart_obj, int c) {
-    uint16_t ch = c;
-    int errcode;
-    uart_tx_data(uart_obj, &ch, 1, &errcode);
-}
-
 void uart_tx_strn(pyb_uart_obj_t *uart_obj, const char *str, uint len) {
     int errcode;
     uart_tx_data(uart_obj, str, len, &errcode);
 }
 
-void uart_tx_strn_cooked(pyb_uart_obj_t *uart_obj, const char *str, uint len) {
-    for (const char *top = str + len; str < top; str++) {
-        if (*str == '\n') {
-            uart_tx_char(uart_obj, '\r');
-        }
-        uart_tx_char(uart_obj, *str);
-    }
-}
-
 // this IRQ handler is set up to handle RXNE interrupts only
 void uart_irq_handler(mp_uint_t uart_id) {
     // get the uart object

ports/stm32/uart.h

@@ -48,6 +48,5 @@ void uart_irq_handler(mp_uint_t uart_id);
 mp_uint_t uart_rx_any(pyb_uart_obj_t *uart_obj);
 int uart_rx_char(pyb_uart_obj_t *uart_obj);
 void uart_tx_strn(pyb_uart_obj_t *uart_obj, const char *str, uint len);
-void uart_tx_strn_cooked(pyb_uart_obj_t *uart_obj, const char *str, uint len);
 
 #endif // MICROPY_INCLUDED_STMHAL_UART_H

ports/stm32/usb.c

@@ -177,20 +177,6 @@ void usb_vcp_send_strn(const char *str, int len) {
 #endif
 }
 
-void usb_vcp_send_strn_cooked(const char *str, int len) {
-#ifdef USE_DEVICE_MODE
-    if (usb_device.enabled) {
-        for (const char *top = str + len; str < top; str++) {
-            if (*str == '\n') {
-                usbd_cdc_tx_always(&usb_device.usbd_cdc_itf, (const uint8_t*)"\r\n", 2);
-            } else {
-                usbd_cdc_tx_always(&usb_device.usbd_cdc_itf, (const uint8_t*)str, 1);
-            }
-        }
-    }
-#endif
-}
-
 /******************************************************************************/
 // MicroPython bindings for USB
 

ports/stm32/usb.h

@@ -63,7 +63,6 @@ void pyb_usb_dev_deinit(void);
 bool usb_vcp_is_enabled(void);
 int usb_vcp_recv_byte(uint8_t *c); // if a byte is available, return 1 and put the byte in *c, else return 0
 void usb_vcp_send_strn(const char* str, int len);
-void usb_vcp_send_strn_cooked(const char *str, int len);
 
 void pyb_usb_host_init(void);
 void pyb_usb_host_process(void);