Commit 7be50f2e authored by Jiri Slaby (SUSE)'s avatar Jiri Slaby (SUSE) Committed by Greg Kroah-Hartman
Browse files

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: default avatar"Jiri Slaby (SUSE)" <jirislaby@kernel.org>
Reported-by: default avatarEmil Kronborg <emil.kronborg@protonmail.com>
Cc: stable <stable@kernel.org>
Fixes: 2d141e68 ("tty: serial: use uart_port_tx() helper")
Closes: https://lore.kernel.org/all/miwgbnvy3hjpnricubg76ytpn7xoceehwahupy25bubbduu23s@om2lptpa26xw/


Tested-by: default avatarStefan Wahren <wahrenst@gmx.net>
Tested-by: default avatarEmil Kronborg <emil.kronborg@protonmail.com>
Link: https://lore.kernel.org/r/20240201105557.28043-2-jirislaby@kernel.org


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 3ee07964

drivers/tty/serial/mxs-auart.c

+4 −1
Original line number Diff line number Diff line
@@ -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)