[PATCH 23/33] serial: 8250: extract serial8250_set_efr()

Jiri Slaby (SUSE)
2025-06-11T10:04:06Z

serial8250_do_set_termios() consists of many registers and up flags
settings. Extract all these into separate functions. This time, setting
of EFR for UART_CAP_EFR ports.

Signed-off-by: Jiri Slaby (SUSE) <jirislaby@kernel.org>
---
drivers/tty/serial/8250/8250_port.c | 43 +++++++++++++++++------------
1 file changed, 25 insertions(+), 18 deletions(-)

diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
index 2c045a4369fc..0f16398cc86f 100644
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -2768,6 +2768,30 @@ static void serial8250_set_ier(struct uart_port *port, struct ktermios *termios)
serial_port_out(port, UART_IER, up->ier);
}

+static void serial8250_set_efr(struct uart_port *port, struct ktermios *termios)
+{
+ struct uart_8250_port *up = up_to_u8250p(port);
+ u8 efr_reg = UART_EFR;
+ u8 efr = 0;
+
+ if (!(up->capabilities & UART_CAP_EFR))
+ return;
+
+ /*
+ * TI16C752/Startech hardware flow control. FIXME:
+ * - TI16C752 requires control thresholds to be set.
+ * - UART_MCR_RTS is ineffective if auto-RTS mode is enabled.
+ */
+ if (termios->c_cflag & CRTSCTS)
+ efr |= UART_EFR_CTS;
+
+ if (port->flags & UPF_EXAR_EFR)
+ efr_reg = UART_XR_EFR;
+
+ serial_port_out(port, UART_LCR, UART_LCR_CONF_MODE_B);
+ serial_port_out(port, efr_reg, efr);
+}
+
void
serial8250_do_set_termios(struct uart_port *port, struct ktermios *termios,
const struct ktermios *old)
@@ -2797,24 +2821,7 @@ serial8250_do_set_termios(struct uart_port *port, struct ktermios *termios,
uart_update_timeout(port, termios->c_cflag, baud);
serial8250_set_errors_and_ignores(port, termios);
serial8250_set_ier(port, termios);
-
- if (up->capabilities & UART_CAP_EFR) {
- unsigned char efr = 0;
- /*
- * TI16C752/Startech hardware flow control. FIXME:
- * - TI16C752 requires control thresholds to be set.
- * - UART_MCR_RTS is ineffective if auto-RTS mode is enabled.
- */
- if (termios->c_cflag & CRTSCTS)
- efr |= UART_EFR_CTS;
-
- serial_port_out(port, UART_LCR, UART_LCR_CONF_MODE_B);
- if (port->flags & UPF_EXAR_EFR)
- serial_port_out(port, UART_XR_EFR, efr);
- else
- serial_port_out(port, UART_EFR, efr);
- }
-
+ serial8250_set_efr(port, termios);
serial8250_set_divisor(port, baud, quot, frac);

/*
--
2.49.0