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serial: sh-sci: Make sure status register SCxSR is read in correct sequence 

commit 3dc4db3662 upstream.

For SCIF and HSCIF interfaces the SCxSR register holds the status of
data that is to be read next from SCxRDR register, But where as for
SCIFA and SCIFB interfaces SCxSR register holds status of data that is
previously read from SCxRDR register.

This patch makes sure the status register is read depending on the port
types so that errors are caught accordingly.

Cc: <stable@vger.kernel.org>
Signed-off-by: Kazuhiro Fujita <kazuhiro.fujita.jg@renesas.com>
Signed-off-by: Hao Bui <hao.bui.yg@renesas.com>
Signed-off-by: KAZUMI HARADA <kazumi.harada.rh@renesas.com>
Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/1585333048-31828-1-git-send-email-kazuhiro.fujita.jg@renesas.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
5.4-rM2-2.2.x-imx-squashed
Kazuhiro Fujita 2020-03-27 18:17:28 +00:00 committed by Greg Kroah-Hartman
parent fceab238c5
commit 3af0614df1
1 changed files with 9 additions and 2 deletions
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11
drivers/tty/serial/sh-sci.c
View File

@ -873,9 +873,16 @@ static void sci_receive_chars(struct uart_port *port)
tty_insert_flip_char(tport, c, TTY_NORMAL);
} else {
for (i = 0; i < count; i++) {
char c = serial_port_in(port, SCxRDR);
char c;
status = serial_port_in(port, SCxSR);
if (port->type == PORT_SCIF ||
port->type == PORT_HSCIF) {
status = serial_port_in(port, SCxSR);
c = serial_port_in(port, SCxRDR);
} else {
c = serial_port_in(port, SCxRDR);
status = serial_port_in(port, SCxSR);
}
if (uart_handle_sysrq_char(port, c)) {
count--; i--;
continue;