Commit 2a3bcfe0 authored by Valentin Caron's avatar Valentin Caron Committed by Greg Kroah-Hartman
Browse files

serial: stm32: fix flow control transfer in DMA mode 



If flow control is enabled, framework will call stop_tx to
pause transfer and then call start_tx to resume transfer.

Clear USART_CR3_DMAT bit in stop_tx ops to pause DMA transfer.

Signed-off-by: default avatarErwan Le Ray <erwan.leray@foss.st.com>
Signed-off-by: default avatarValentin Caron <valentin.caron@foss.st.com>
Link: https://lore.kernel.org/r/20220104182445.4195-4-valentin.caron@foss.st.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 9a135f16

drivers/tty/serial/stm32-usart.c

+3 −0
Original line number Diff line number Diff line
@@ -707,8 +707,11 @@ static void stm32_usart_stop_tx(struct uart_port *port) 
{

	struct stm32_port *stm32_port = to_stm32_port(port);

	struct serial_rs485 *rs485conf = &port->rs485;

	const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;



	stm32_usart_tx_interrupt_disable(port);

	if (stm32_usart_tx_dma_started(stm32_port) && stm32_usart_tx_dma_enabled(stm32_port))

		stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_DMAT);



	if (rs485conf->flags & SER_RS485_ENABLED) {

		if (rs485conf->flags & SER_RS485_RTS_ON_SEND) {