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serial: sh-sci: Terminate TX DMA during buffer flushing 

While the .flush_buffer() callback clears sci_port.tx_dma_len since
commit 1cf4a7efdc ("serial: sh-sci: Fix race condition causing
garbage during shutdown"), it does not terminate a transmit DMA
operation that may be in progress.

Fix this by terminating any pending DMA operations, and resetting the
corresponding cookie.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Eugeniu Rosca <erosca@de.adit-jv.com>
Tested-by: Eugeniu Rosca <erosca@de.adit-jv.com>

Link: https://lore.kernel.org/r/20190624123540.20629-3-geert+renesas@glider.be
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
alistair/sunxi64-5.4-dsi
Geert Uytterhoeven 2019-06-24 14:35:40 +02:00 committed by Greg Kroah-Hartman
parent 8493eab026
commit 775b7ffd7d
1 changed files with 9 additions and 2 deletions
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11
drivers/tty/serial/sh-sci.c
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@ -1656,11 +1656,18 @@ static void sci_free_dma(struct uart_port *port)
static void sci_flush_buffer(struct uart_port *port)
{
struct sci_port *s = to_sci_port(port);
/*
* In uart_flush_buffer(), the xmit circular buffer has just been
* cleared, so we have to reset tx_dma_len accordingly.
* cleared, so we have to reset tx_dma_len accordingly, and stop any
* pending transfers
*/
to_sci_port(port)->tx_dma_len = 0;
s->tx_dma_len = 0;
if (s->chan_tx) {
dmaengine_terminate_async(s->chan_tx);
s->cookie_tx = -EINVAL;
}
}
#else /* !CONFIG_SERIAL_SH_SCI_DMA */
static inline void sci_request_dma(struct uart_port *port)