Commit 3d82be8b authored by Erwan Le Ray's avatar Erwan Le Ray Committed by Greg Kroah-Hartman
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serial: stm32: add support for "flush_buffer" ops 



Add the support for "flush_buffer" ops in order to flush any write buffers,
reset any DMA state and stop any ongoing DMA transfers when the
port->state->xmit circular buffer is cleared.

Signed-off-by: default avatarErwan Le Ray <erwan.leray@foss.st.com>
Link: https://lore.kernel.org/r/20210304162308.8984-14-erwan.leray@foss.st.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 3db1d524

drivers/tty/serial/stm32-usart.c

+14 −0
Original line number Diff line number Diff line
@@ -597,6 +597,19 @@ static void stm32_usart_start_tx(struct uart_port *port) 
	stm32_usart_transmit_chars(port);

}



/* Flush the transmit buffer. */

static void stm32_usart_flush_buffer(struct uart_port *port)

{

	struct stm32_port *stm32_port = to_stm32_port(port);

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



	if (stm32_port->tx_ch) {

		dmaengine_terminate_async(stm32_port->tx_ch);

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

		stm32_port->tx_dma_busy = false;

	}

}



/* Throttle the remote when input buffer is about to overflow. */

static void stm32_usart_throttle(struct uart_port *port)

{
@@ -992,6 +1005,7 @@ static const struct uart_ops stm32_uart_ops = { 
	.break_ctl	= stm32_usart_break_ctl,

	.startup	= stm32_usart_startup,

	.shutdown	= stm32_usart_shutdown,

	.flush_buffer	= stm32_usart_flush_buffer,

	.set_termios	= stm32_usart_set_termios,

	.pm		= stm32_usart_pm,

	.type		= stm32_usart_type,