Commit 775b7ffd authored Jun 24, 2019 by Geert Uytterhoeven Committed by Greg Kroah-Hartman Jul 03, 2019

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



While the .flush_buffer() callback clears sci_port.tx_dma_len since
commit 1cf4a7ef ("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>

parent 8493eab0

drivers/tty/serial/sh-sci.c

+9 −2

Original line number	Diff line number	Diff line
		@@ -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)

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