Commit 89d82324 authored by Richard Genoud's avatar Richard Genoud Committed by Greg Kroah-Hartman

tty/serial: atmel_serial: BUG: stop DMA from transmitting in stop_tx

If we don't disable the transmitter in atmel_stop_tx, the DMA buffer
continues to send data until it is emptied.
This cause problems with the flow control (CTS is asserted and data are
still sent).

So, disabling the transmitter in atmel_stop_tx is a sane thing to do.

Tested on at91sam9g35-cm(DMA)
Tested for regressions on sama5d2-xplained(Fifo) and at91sam9g20ek(PDC)

Cc: <stable@vger.kernel.org> (beware, this won't apply before 4.3)
Signed-off-by: default avatarRichard Genoud <richard.genoud@gmail.com>
Acked-by: default avatarNicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent a121103c
...@@ -481,6 +481,14 @@ static void atmel_stop_tx(struct uart_port *port) ...@@ -481,6 +481,14 @@ static void atmel_stop_tx(struct uart_port *port)
/* disable PDC transmit */ /* disable PDC transmit */
atmel_uart_writel(port, ATMEL_PDC_PTCR, ATMEL_PDC_TXTDIS); atmel_uart_writel(port, ATMEL_PDC_PTCR, ATMEL_PDC_TXTDIS);
} }
/*
* Disable the transmitter.
* This is mandatory when DMA is used, otherwise the DMA buffer
* is fully transmitted.
*/
atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_TXDIS);
/* Disable interrupts */ /* Disable interrupts */
atmel_uart_writel(port, ATMEL_US_IDR, atmel_port->tx_done_mask); atmel_uart_writel(port, ATMEL_US_IDR, atmel_port->tx_done_mask);
...@@ -513,6 +521,9 @@ static void atmel_start_tx(struct uart_port *port) ...@@ -513,6 +521,9 @@ static void atmel_start_tx(struct uart_port *port)
/* Enable interrupts */ /* Enable interrupts */
atmel_uart_writel(port, ATMEL_US_IER, atmel_port->tx_done_mask); atmel_uart_writel(port, ATMEL_US_IER, atmel_port->tx_done_mask);
/* re-enable the transmitter */
atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_TXEN);
} }
/* /*
......
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