aux_serial: Moved the transmit buffer swap function declaration into aux_serial.h and implemented a function to get the current buffer

src/platforms/common/aux_serial.c

@@ -93,4 +93,9 @@ void aux_serial_switch_transmit_buffers(void)
 	buf_tx_act_sz = 0;
 	buf_tx_act_idx ^= 1;
 }
+
+char *aux_serial_current_transmit_buffer(void)
+{
+	return buf_tx + (buf_tx_act_idx * TX_BUF_SIZE);
+}
 #endif

src/platforms/common/aux_serial.h

@@ -26,4 +26,9 @@
 void aux_serial_init(void);
 void aux_serial_set_encoding(struct usb_cdc_line_coding *coding);
 
+#if defined(STM32F0) || defined(STM32F1) || defined(STM32F3) || defined(STM32F4)
+void aux_serial_switch_transmit_buffers(void);
+char *aux_serial_current_transmit_buffer(void);
+#endif
+
 #endif /*AUX_SERIAL_H*/

src/platforms/common/usb_serial.c

@@ -317,7 +317,7 @@ static void debug_uart_receive_callback(usbd_device *dev, uint8_t ep)
 	usbd_ep_nak_set(dev, CDCACM_UART_ENDPOINT, 1);
 
 	/* Read new packet directly into TX buffer */
-	char *const tx_buf_ptr = &buf_tx[buf_tx_act_idx * TX_BUF_SIZE];
+	char *const tx_buf_ptr = aux_serial_current_transmit_buffer();
 	const uint16_t len = usbd_ep_read_packet(dev, CDCACM_UART_ENDPOINT, tx_buf_ptr + buf_tx_act_sz, CDCACM_PACKET_SIZE);
 
 #if defined(BLACKMAGIC)

src/platforms/common/usbuart.h

@@ -23,7 +23,6 @@
 #include "general.h"
 
 void usbuart_set_led_state(uint8_t ledn, bool state);
-void aux_serial_switch_transmit_buffers(void);
 void debug_uart_run(void);
 
 #define TX_LED_ACT (1 << 0)