From: Geert Uytterhoeven Date: Sun, 26 Jun 2016 09:20:21 +0000 (+0200) Subject: serial: sh-sci: Stop transfers in sci_shutdown() X-Git-Tag: v4.8-rc1~192^2~2 X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=5fd2b6ee7a319e0955acff96948fae57321b1f5a;p=linux-2.6-block.git serial: sh-sci: Stop transfers in sci_shutdown() Make sure the transmitter and receiver are stopped when shutting down the port, and related interrupts are disabled. Without this: - New input data may be received into the RX FIFO, possibly triggering a new RX DMA completion, - Transfers will still be enabled on a subsequent startup of the UART, before the UART's FIFOs have been reset, causing reading of stale data. Inspired by a patch in the BSP by Koji Matsuoka . Signed-off-by: Geert Uytterhoeven Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c index 432d9acabf7f..d86eee38aae6 100644 --- a/drivers/tty/serial/sh-sci.c +++ b/drivers/tty/serial/sh-sci.c @@ -1989,6 +1989,7 @@ static void sci_shutdown(struct uart_port *port) { struct sci_port *s = to_sci_port(port); unsigned long flags; + u16 scr; dev_dbg(port->dev, "%s(%d)\n", __func__, port->line); @@ -1998,6 +1999,9 @@ static void sci_shutdown(struct uart_port *port) spin_lock_irqsave(&port->lock, flags); sci_stop_rx(port); sci_stop_tx(port); + /* Stop RX and TX, disable related interrupts, keep clock source */ + scr = serial_port_in(port, SCSCR); + serial_port_out(port, SCSCR, scr & (SCSCR_CKE1 | SCSCR_CKE0)); spin_unlock_irqrestore(&port->lock, flags); #ifdef CONFIG_SERIAL_SH_SCI_DMA