serial: sh: Improve FIFO empty check on RX
If the SCIF is receiving data quickly enough, it may happen that the
SCxSR_RDxF flag is cleared in sh_serial_getc_generic(), while the
FIFO still contains data. If that happens, the serial_getc_check()
reports no data in the FIFO as the flag is no longer set. Add one
more check, if the SCxSR_RDxF is not set, read out the FIFO level
and if there are still characters in the FIFO, permit reading them
out.
Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
Cc: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>
diff --git a/drivers/serial/serial_sh.c b/drivers/serial/serial_sh.c
index 13b179f..e27d256 100644
--- a/drivers/serial/serial_sh.c
+++ b/drivers/serial/serial_sh.c
@@ -116,7 +116,10 @@
handle_error(port);
if (sci_in(port, SCLSR) & SCxSR_ORER(port))
handle_error(port);
- return status & (SCIF_DR | SCxSR_RDxF(port));
+ status &= (SCIF_DR | SCxSR_RDxF(port));
+ if (status)
+ return status;
+ return scif_rxfill(port);
}
static int sh_serial_getc_generic(struct uart_port *port)