Commit 0f9f1884 authored by Krzysztof Chruściński's avatar Krzysztof Chruściński Committed by Carles Cufi
Browse files

drivers: serial: nrfx_uarte: Add workaround for bytes dropping 

Add workaround for development kits on which interface chip (segger chip)
is dropping bytes when they are sent in bursts. Issue has been seen on
DK which have multiple virtual com ports on the USB.

A workaround is adding periodic busy waits to introduce gaps in the
transmission.

Signed-off-by: default avatarKrzysztof Chruscinski <krzysztof.chruscinski@nordicsemi.no>
parent 1c705227

drivers/serial/Kconfig.nrfx

+26 −0
Changes for drivers/serial/Kconfig.nrfx: 26 added lines, 0 removed lines.
Original line number Diff line number Diff line
@@ -27,6 +27,32 @@ config UART_ASYNC_TX_CACHE_SIZE 
	  in RAM, because EasyDMA in UARTE peripherals can only transfer data

	  from RAM.



config UART_NRF_DK_SERIAL_WORKAROUND

	bool

	help

	  On some development kits there are characters being dropped by the

	  controller chip (Segger interface) if there are burst of bytes being

	  printed. It can lead to test failures since test out is corrupted.

	  A workaround is to enforce gaps (by adding busy waits) in the transmission.

	  It is recommended to enable the workaround only in the test since

	  busy waits can impact application flow.



if UART_NRF_DK_SERIAL_WORKAROUND



config UART_NRF_DK_SERIAL_WORKAROUND_COUNT

	int

	default 32

	help

	  Number of bytes transferred after which a busy wait is added.



config UART_NRF_DK_SERIAL_WORKAROUND_WAIT_MS

	int

	default 10

	help

	  Busy wait time (in milliseconds).

endif





# ----------------- port 0 -----------------

config UART_0_NRF_UART

	def_bool HAS_HW_NRF_UART0

drivers/serial/uart_nrfx_uarte.c

+26 −0
Changes for drivers/serial/uart_nrfx_uarte.c: 26 added lines, 0 removed lines.
Original line number Diff line number Diff line
@@ -1539,6 +1539,32 @@ static void uarte_nrfx_poll_out(const struct device *dev, unsigned char c) 
	bool isr_mode = k_is_in_isr() || k_is_pre_kernel();

	unsigned int key;



#if CONFIG_UART_NRF_DK_SERIAL_WORKAROUND

	/* On some boards (usually those which have multiple virtual coms) it can

	 * be seen that bytes are dropped on the console serial (serial that goes

	 * through Segger interface chip) when working in virtual environment.

	 * It's the Segger chip that drops those bytes. A workaround is to enforce

	 * periodic gaps which allows to handle the traffic correctly.

	 */

	if (dev == DEVICE_DT_GET(DT_CHOSEN(zephyr_console))) {

		static int cnt;

		static uint32_t t;

		uint32_t now = k_uptime_get_32();



		if ((now - t) >= CONFIG_UART_NRF_DK_SERIAL_WORKAROUND_WAIT_MS) {

			cnt = 0;

		} else {

			cnt++;

			if (cnt >= CONFIG_UART_NRF_DK_SERIAL_WORKAROUND_COUNT) {

				k_busy_wait(1000 * CONFIG_UART_NRF_DK_SERIAL_WORKAROUND_WAIT_MS);

				cnt = 0;

			}

		}



		t = now;

	}

#endif



	if (isr_mode) {

		while (1) {

			key = irq_lock();

CRA Git | Maintained and supported by SUSTech CRA and CCSE