This is a note to let you know that I've just added the patch titled
tty/serial: atmel: fix RS485 half duplex with DMA
to my tty git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty.git
in the tty-testing branch.
The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)
The patch will be merged to the tty-next branch sometime soon,
after it passes testing, and the merge window is open.
If you have any questions about this process, please let me know.
>From 0058f0871efe7b01c6f2b3046c68196ab73e96da Mon Sep 17 00:00:00 2001
From: Alexandre Belloni <alexandre.belloni@xxxxxxxxxxxxxxxxxx>
Date: Sat, 28 May 2016 00:54:08 +0200
Subject: 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: Alexandre Belloni <alexandre.belloni@xxxxxxxxxxxxxxxxxx>
Acked-by: Nicolas Ferre <nicolas.ferre@xxxxxxxxx>
Cc: stable <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/tty/serial/atmel_serial.c | 14 ++++++++------
1 file changed, 8 insertions(+), 6 deletions(-)
diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
index 857016367a7a..f887c1df23e6 100644
--- a/drivers/tty/serial/atmel_serial.c
+++ b/drivers/tty/serial/atmel_serial.c
@@ -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)
- /* 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);
}
--
2.9.0
--
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