From 92b779cd9f1493dad467b08e94c916b66270c47c Mon Sep 17 00:00:00 2001 From: Marek Vasut Date: Sun, 7 Sep 2025 21:16:27 +0200 Subject: [PATCH] serial: sh: Handle HSCIF RX FIFO overflow The HSCIF RX FIFO may overflow when data are streaming from remote end into the HSCIF while U-Boot is still starting up. In that case, HSFSR bit RDF is set, but HSFDR field R is zero. This confuses .tstc callback into considering RX FIFO to be empty, which leads to .getc to be never invoked, even when user attempts to pass more input onto the command line. Fix this by considering the RDF flag in serial_rx_fifo_level(), which is called from .tstc in case of no errors. If RDF flag is set, trigger the .getc callback and let it clear the RX FIFO. Signed-off-by: Marek Vasut --- drivers/serial/serial_sh.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/drivers/serial/serial_sh.c b/drivers/serial/serial_sh.c index e4cc4ee4260..7ab62e0e90b 100644 --- a/drivers/serial/serial_sh.c +++ b/drivers/serial/serial_sh.c @@ -112,7 +112,16 @@ static int serial_raw_putc(struct uart_port *port, const char c) static int serial_rx_fifo_level(struct uart_port *port) { - return scif_rxfill(port); + int ret; + + ret = scif_rxfill(port); + if (ret) + return ret; + + if (sci_in(port, SCxSR) & SCxSR_RDxF(port)) + return 1; + + return 0; } static int sh_serial_tstc_generic(struct uart_port *port) -- 2.47.3