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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>
This commit is contained in:
Geert Uytterhoeven 2015-08-21 20:02:55 +02:00 committed by Greg Kroah-Hartman
parent 7b39d90184
commit e6403c112f
1 changed files with 3 additions and 1 deletions
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4
drivers/tty/serial/sh-sci.c
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@ -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));