From 3af0614df15c1c1fbfafed4888f12d76a7b044e1 Mon Sep 17 00:00:00 2001 From: Kazuhiro Fujita Date: Fri, 27 Mar 2020 18:17:28 +0000 Subject: [PATCH] serial: sh-sci: Make sure status register SCxSR is read in correct sequence commit 3dc4db3662366306e54ddcbda4804acb1258e4ba 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: Signed-off-by: Kazuhiro Fujita Signed-off-by: Hao Bui Signed-off-by: KAZUMI HARADA Signed-off-by: Lad Prabhakar Tested-by: Geert Uytterhoeven Link: https://lore.kernel.org/r/1585333048-31828-1-git-send-email-kazuhiro.fujita.jg@renesas.com Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/sh-sci.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c index 22e5d4e13714..7d1529b11ae9 100644 --- a/drivers/tty/serial/sh-sci.c +++ b/drivers/tty/serial/sh-sci.c @@ -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;