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Commit 6c5962f3 authored by Erwan Le Ray's avatar Erwan Le Ray Committed by Greg Kroah-Hartman
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serial: stm32: fix rx data length when parity enabled 



- Fixes a rx data error when data length < 8 bits and parity is enabled.
RDR register MSB is used for parity bit reception.
- Adds a mask to ignore MSB when data is get from RDR.

Fixes: 34891872 ("serial: stm32: adding dma support")
Signed-off-by: default avatarErwan Le Ray <erwan.leray@st.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 4f01d833

drivers/tty/serial/stm32-usart.c

+8 −4
Original line number Diff line number Diff line
@@ -194,8 +194,8 @@ static int stm32_pending_rx(struct uart_port *port, u32 *sr, int *last_res, 
	return 0;

}



static unsigned long

stm32_get_char(struct uart_port *port, u32 *sr, int *last_res)

static unsigned long stm32_get_char(struct uart_port *port, u32 *sr,

				    int *last_res)

{

	struct stm32_port *stm32_port = to_stm32_port(port);

	struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
@@ -205,10 +205,13 @@ stm32_get_char(struct uart_port *port, u32 *sr, int *last_res) 
		c = stm32_port->rx_buf[RX_BUF_L - (*last_res)--];

		if ((*last_res) == 0)

			*last_res = RX_BUF_L;

		return c;

	} else {

		return readl_relaxed(port->membase + ofs->rdr);

		c = readl_relaxed(port->membase + ofs->rdr);

		/* apply RDR data mask */

		c &= stm32_port->rdr_mask;

	}



	return c;

}



static void stm32_receive_chars(struct uart_port *port, bool threaded)
@@ -679,6 +682,7 @@ static void stm32_set_termios(struct uart_port *port, struct ktermios *termios, 
		cr2 |= USART_CR2_STOP_2B;



	bits = stm32_get_databits(termios);

	stm32_port->rdr_mask = (BIT(bits) - 1);



	if (cflag & PARENB) {

		bits++;

drivers/tty/serial/stm32-usart.h

+1 −0
Original line number Diff line number Diff line
@@ -254,6 +254,7 @@ struct stm32_port { 
	bool hw_flow_control;

	bool fifoen;

	int wakeirq;

	int rdr_mask;		/* receive data register mask */

};



static struct stm32_port stm32_ports[STM32_MAX_PORTS];