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Commit 0058f087 authored by Alexandre Belloni's avatar Alexandre Belloni Committed by Greg Kroah-Hartman
Browse files

tty/serial: atmel: fix RS485 half duplex with DMA 



When using DMA, half duplex doesn't work properly because rx is not stopped
before starting tx. Ensure we call atmel_stop_rx() in the DMA case.

Signed-off-by: default avatarAlexandre Belloni <alexandre.belloni@free-electrons.com>
Acked-by: default avatarNicolas Ferre <nicolas.ferre@atmel.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 637ba54f

drivers/tty/serial/atmel_serial.c

+8 −6
Original line number Diff line number Diff line
@@ -487,19 +487,21 @@ static void atmel_start_tx(struct uart_port *port) 
{

	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);



	if (atmel_use_pdc_tx(port)) {

		if (atmel_uart_readl(port, ATMEL_PDC_PTSR) & ATMEL_PDC_TXTEN)

	if (atmel_use_pdc_tx(port) && (atmel_uart_readl(port, ATMEL_PDC_PTSR)

				       & ATMEL_PDC_TXTEN))

		/* The transmitter is already running.  Yes, we

		   really need this.*/

		return;



	if (atmel_use_pdc_tx(port) || atmel_use_dma_tx(port))

		if ((port->rs485.flags & SER_RS485_ENABLED) &&

		    !(port->rs485.flags & SER_RS485_RX_DURING_TX))

			atmel_stop_rx(port);



	if (atmel_use_pdc_tx(port))

		/* re-enable PDC transmit */

		atmel_uart_writel(port, ATMEL_PDC_PTCR, ATMEL_PDC_TXTEN);

	}



	/* Enable interrupts */

	atmel_uart_writel(port, ATMEL_US_IER, atmel_port->tx_done_mask);

}