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Commit bfc2e07f authored by Stefan Agner's avatar Stefan Agner Committed by Greg Kroah-Hartman
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tty: serial: fsl_lpuart: terminate DMA on buffer flush 



On uart buffer flush, serial core resets the circular buffer.
If a DMA transfer is in progress at that time, the callback
lpuart_dma_tx_complete will move buffer's tail unconditionally,
hence tail moves beyond head. Use the flush_buffer hook to
terminate the DMA imeaditely and avoid lpuart_dma_tx_complete
being called in this situation.

This bug often showed up while shutdown and lead to duplicate
serial console output.

Signed-off-by: default avatarStefan Agner <stefan@agner.ch>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 2fe605df

drivers/tty/serial/fsl_lpuart.c

+11 −0
Original line number Diff line number Diff line
@@ -455,6 +455,15 @@ static int lpuart_dma_rx(struct lpuart_port *sport) 
	return 0;

}



static void lpuart_flush_buffer(struct uart_port *port)

{

	struct lpuart_port *sport = container_of(port, struct lpuart_port, port);

	if (sport->lpuart_dma_tx_use) {

		dmaengine_terminate_all(sport->dma_tx_chan);

		sport->dma_tx_in_progress = 0;

	}

}



static void lpuart_dma_rx_complete(void *arg)

{

	struct lpuart_port *sport = arg;
@@ -1496,6 +1505,7 @@ static struct uart_ops lpuart_pops = { 
	.release_port	= lpuart_release_port,

	.config_port	= lpuart_config_port,

	.verify_port	= lpuart_verify_port,

	.flush_buffer	= lpuart_flush_buffer,

};



static struct uart_ops lpuart32_pops = {
@@ -1514,6 +1524,7 @@ static struct uart_ops lpuart32_pops = { 
	.release_port	= lpuart_release_port,

	.config_port	= lpuart_config_port,

	.verify_port	= lpuart_verify_port,

	.flush_buffer	= lpuart_flush_buffer,

};



static struct lpuart_port *lpuart_ports[UART_NR];