6.7-stable review patch. If anyone has any objections, please let me know.
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From: Jiri Slaby (SUSE) jirislaby@kernel.org
commit 7be50f2e8f20fc2299069b28dea59a28e3abe20a upstream.
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)" jirislaby@kernel.org Reported-by: Emil Kronborg emil.kronborg@protonmail.com Cc: stable stable@kernel.org Fixes: 2d141e683e9a ("tty: serial: use uart_port_tx() helper") Closes: https://lore.kernel.org/all/miwgbnvy3hjpnricubg76ytpn7xoceehwahupy25bubbduu2... Tested-by: Stefan Wahren wahrenst@gmx.net Tested-by: Emil Kronborg emil.kronborg@protonmail.com Link: https://lore.kernel.org/r/20240201105557.28043-2-jirislaby@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/tty/serial/mxs-auart.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
--- 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 mx 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)