Commit e6403c11 authored Aug 21, 2015 by Geert Uytterhoeven Committed by Greg Kroah-Hartman Oct 04, 2015

serial: sh-sci: Don't call sci_rx_interrupt() on error when using DMA



The error handler calls sci_rx_interrupt() to drain the receive FIFO if
an error condition happens.

However, if DMA is enabled on SCIFA or SCIFB, this will call
disable_irq_nosync() twice. Due to this imbalance, the receive interrupt
will never be re-enabled, and reception stops forever.

To fix this, restrict draining the FIFO to PIO mode, and just call
sci_receive_chars() directly.

Inspired by a patch from Yoshihiro Shimoda
<yoshihiro.shimoda.uh@renesas.com>.

Reported-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 7b39d901

drivers/tty/serial/sh-sci.c

+3 −1

Original line number	Diff line number	Diff line
		@@ -993,6 +993,7 @@ static irqreturn_t sci_tx_interrupt(int irq, void *ptr)
		static irqreturn_t sci_er_interrupt(int irq, void *ptr)
		{
		struct uart_port *port = ptr;
		struct sci_port *s = to_sci_port(port);

		/* Handle errors */
		if (port->type == PORT_SCI) {
		@@ -1003,7 +1004,8 @@ static irqreturn_t sci_er_interrupt(int irq, void *ptr)
		}
		} else {
		sci_handle_fifo_overrun(port);
		sci_rx_interrupt(irq, ptr);
		if (!s->chan_rx)
		sci_receive_chars(ptr);
		}

		sci_clear_SCxSR(port, SCxSR_ERROR_CLEAR(port));