From 2a3bcfe03725472607110507b6860d823e0deb41 Mon Sep 17 00:00:00 2001 From: Valentin Caron Date: Tue, 4 Jan 2022 19:24:44 +0100 Subject: 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: Erwan Le Ray Signed-off-by: Valentin Caron Link: https://lore.kernel.org/r/20220104182445.4195-4-valentin.caron@foss.st.com Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/stm32-usart.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'drivers/tty') diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c index 52755a576bc2..788e002688f2 100644 --- a/drivers/tty/serial/stm32-usart.c +++ b/drivers/tty/serial/stm32-usart.c @@ -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) { -- cgit