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serial: sh-sci: Stop transfers in sci_shutdown()

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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
<koji.matsuoka.xm@renesas.com>.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Geert Uytterhoeven 2016-06-26 11:20:21 +02:00 committed by Greg Kroah-Hartman
parent 755dd8aa12
commit 5fd2b6ee7a
1 changed files with 4 additions and 0 deletions
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4
drivers/tty/serial/sh-sci.c
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@ -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