Commit 5541a9ba authored by Michael Walle's avatar Michael Walle Committed by Greg Kroah-Hartman
Browse files

serial: fsl_lpuart: handle break and make sysrq work 



Although there is already sysrq characters handling, a break condition
was never detected. Add support for it.

The LPUART can't distinguish between a framing error and a break
condition. We assume it is a break if the received data is all zero.

Signed-off-by: default avatarMichael Walle <michael@walle.cc>
Link: https://lore.kernel.org/r/20210512141255.18277-6-michael@walle.cc


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 5697df73

drivers/tty/serial/fsl_lpuart.c

+24 −8
Original line number Diff line number Diff line
@@ -910,6 +910,7 @@ static void lpuart32_rxint(struct lpuart_port *sport) 
	unsigned int flg, ignored = 0;

	struct tty_port *port = &sport->port.state->port;

	unsigned long rx, sr;

	bool is_break;



	spin_lock(&sport->port.lock);
@@ -924,14 +925,27 @@ static void lpuart32_rxint(struct lpuart_port *sport) 
		rx = lpuart32_read(&sport->port, UARTDATA);

		rx &= UARTDATA_MASK;



		/*

		 * The LPUART can't distinguish between a break and a framing error,

		 * thus we assume it is a break if the received data is zero.

		 */

		is_break = (sr & UARTSTAT_FE) && !rx;



		if (is_break && uart_handle_break(&sport->port))

			continue;



		if (uart_prepare_sysrq_char(&sport->port, rx))

			continue;



		if (sr & (UARTSTAT_PE | UARTSTAT_OR | UARTSTAT_FE)) {

			if (sr & UARTSTAT_PE)

			if (sr & UARTSTAT_PE) {

				if (is_break)

					sport->port.icount.brk++;

				else

					sport->port.icount.parity++;

			else if (sr & UARTSTAT_FE)

			} else if (sr & UARTSTAT_FE) {

				sport->port.icount.frame++;

			}



			if (sr & UARTSTAT_OR)

				sport->port.icount.overrun++;
@@ -944,15 +958,17 @@ static void lpuart32_rxint(struct lpuart_port *sport) 


			sr &= sport->port.read_status_mask;



			if (sr & UARTSTAT_PE)

			if (sr & UARTSTAT_PE) {

				if (is_break)

					flg = TTY_BREAK;

				else

					flg = TTY_PARITY;

			else if (sr & UARTSTAT_FE)

			} else if (sr & UARTSTAT_FE) {

				flg = TTY_FRAME;

			}



			if (sr & UARTSTAT_OR)

				flg = TTY_OVERRUN;



			sport->port.sysrq = 0;

		}



		tty_insert_flip_char(port, rx, flg);