Commit cf61375f authored by Alexandre Belloni's avatar Alexandre Belloni Committed by Sasha Levin

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

[ Upstream commit 0058f087 ]

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>
Signed-off-by: default avatarSasha Levin <alexander.levin@verizon.com>
parent ebe13983
......@@ -431,19 +431,21 @@ 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)
/* The transmitter is already running. Yes, we
really need this.*/
return;
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);
}
......
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