From 7be50f2e8f20fc2299069b28dea59a28e3abe20a Mon Sep 17 00:00:00 2001 From: "Jiri Slaby (SUSE)" Date: Thu, 1 Feb 2024 11:55:57 +0100 Subject: serial: mxs-auart: fix tx Emil reports: After updating Linux on an i.MX28 board, serial communication over AUART broke. When I TX from the board and measure on the TX pin, it seems like the HW fifo is not emptied before the transmission is stopped. MXS performs weird things with stop_tx(). The driver makes it conditional on uart_tx_stopped(). So the driver needs special handling. Pass the brand new UART_TX_NOSTOP to uart_port_tx_flags() and handle the stop on its own. Signed-off-by: "Jiri Slaby (SUSE)" Reported-by: Emil Kronborg Cc: stable Fixes: 2d141e683e9a ("tty: serial: use uart_port_tx() helper") Closes: https://lore.kernel.org/all/miwgbnvy3hjpnricubg76ytpn7xoceehwahupy25bubbduu23s@om2lptpa26xw/ Tested-by: Stefan Wahren Tested-by: Emil Kronborg Link: https://lore.kernel.org/r/20240201105557.28043-2-jirislaby@kernel.org Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/mxs-auart.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'drivers/tty') diff --git a/drivers/tty/serial/mxs-auart.c b/drivers/tty/serial/mxs-auart.c index 3ec725555bcc..4749331fe618 100644 --- a/drivers/tty/serial/mxs-auart.c +++ b/drivers/tty/serial/mxs-auart.c @@ -605,13 +605,16 @@ static void mxs_auart_tx_chars(struct mxs_auart_port *s) return; } - pending = uart_port_tx(&s->port, ch, + pending = uart_port_tx_flags(&s->port, ch, UART_TX_NOSTOP, !(mxs_read(s, REG_STAT) & AUART_STAT_TXFF), mxs_write(ch, s, REG_DATA)); if (pending) mxs_set(AUART_INTR_TXIEN, s, REG_INTR); else mxs_clr(AUART_INTR_TXIEN, s, REG_INTR); + + if (uart_tx_stopped(&s->port)) + mxs_auart_stop_tx(&s->port); } static void mxs_auart_rx_char(struct mxs_auart_port *s) -- cgit