1 files changed, 30 insertions, 6 deletions

diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c
index bce4ac1787ad..d8e1b0356e33 100644
--- a/drivers/tty/serial/stm32-usart.c
+++ b/drivers/tty/serial/stm32-usart.c
@@ -72,6 +72,8 @@ static void stm32_config_reg_rs485(u32 *cr1, u32 *cr3, u32 delay_ADE,
 	*cr3 |= USART_CR3_DEM;
 	over8 = *cr1 & USART_CR1_OVER8;
 
+	*cr1 &= ~(USART_CR1_DEDT_MASK | USART_CR1_DEAT_MASK);
+
 	if (over8)
 		rs485_deat_dedt = delay_ADE * baud * 8;
 	else
@@ -472,7 +474,10 @@ static unsigned int stm32_tx_empty(struct uart_port *port)
 	struct stm32_port *stm32_port = to_stm32_port(port);
 	struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
 
-	return readl_relaxed(port->membase + ofs->isr) & USART_SR_TXE;
+	if (readl_relaxed(port->membase + ofs->isr) & USART_SR_TC)
+		return TIOCSER_TEMT;
+
+	return 0;
 }
 
 static void stm32_set_mctrl(struct uart_port *port, unsigned int mctrl)
@@ -506,7 +511,7 @@ static void stm32_start_tx(struct uart_port *port)
 {
 	struct circ_buf *xmit = &port->state->xmit;
 
-	if (uart_circ_empty(xmit))
+	if (uart_circ_empty(xmit) && !port->x_char)
 		return;
 
 	stm32_transmit_chars(port);
@@ -637,8 +642,9 @@ static void stm32_set_termios(struct uart_port *port, struct ktermios *termios,
 	unsigned int baud, bits;
 	u32 usartdiv, mantissa, fraction, oversampling;
 	tcflag_t cflag = termios->c_cflag;
-	u32 cr1, cr2, cr3;
+	u32 cr1, cr2, cr3, isr;
 	unsigned long flags;
+	int ret;
 
 	if (!stm32_port->hw_flow_control)
 		cflag &= ~CRTSCTS;
@@ -647,6 +653,15 @@ static void stm32_set_termios(struct uart_port *port, struct ktermios *termios,
 
 	spin_lock_irqsave(&port->lock, flags);
 
+	ret = readl_relaxed_poll_timeout_atomic(port->membase + ofs->isr,
+						isr,
+						(isr & USART_SR_TC),
+						10, 100000);
+
+	/* Send the TC error message only when ISR_TC is not set. */
+	if (ret)
+		dev_err(port->dev, "Transmission is not complete\n");
+
 	/* Stop serial port and reset value */
 	writel_relaxed(0, port->membase + ofs->cr1);
 
@@ -675,13 +690,22 @@ static void stm32_set_termios(struct uart_port *port, struct ktermios *termios,
 	 * CS8 or (CS7 + parity), 8 bits word aka [M1:M0] = 0b00
 	 * M0 and M1 already cleared by cr1 initialization.
 	 */
-	if (bits == 9)
+	if (bits == 9) {
 		cr1 |= USART_CR1_M0;
-	else if ((bits == 7) && cfg->has_7bits_data)
+	} else if ((bits == 7) && cfg->has_7bits_data) {
 		cr1 |= USART_CR1_M1;
-	else if (bits != 8)
+	} else if (bits != 8) {
 		dev_dbg(port->dev, "Unsupported data bits config: %u bits\n"
 			, bits);
+		cflag &= ~CSIZE;
+		cflag |= CS8;
+		termios->c_cflag = cflag;
+		bits = 8;
+		if (cflag & PARENB) {
+			bits++;
+			cr1 |= USART_CR1_M0;
+		}
+	}
 
 	if (cflag & PARODD)
 		cr1 |= USART_CR1_PS;