serial: 8250: extract serial8250_set_trigger_for_slow_speed()

serial8250_do_set_termios() consists of many registers and up flags
settings. Extract all these into separate functions. This time, setting
of trigger level for slow speeds.

Signed-off-by: "Jiri Slaby (SUSE)" <jirislaby@kernel.org>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20250611100319.186924-20-jirislaby@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
index edfbaa6b7a1bdb0c70ba22ea3182b72ba2c89fb4..52385314c42645511ea983a0e8d86c04f2edbf21 100644 (file)
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -2686,6 +2686,24 @@ static void serial8250_set_mini(struct uart_port *port, struct ktermios *termios
        }
 }
 
+static void serial8250_set_trigger_for_slow_speed(struct uart_port *port, struct ktermios *termios,
+                                                 unsigned int baud)
+{
+       struct uart_8250_port *up = up_to_u8250p(port);
+
+       if (!(up->capabilities & UART_CAP_FIFO))
+               return;
+       if (port->fifosize <= 1)
+               return;
+       if (baud >= 2400)
+               return;
+       if (up->dma)
+               return;
+
+       up->fcr &= ~UART_FCR_TRIGGER_MASK;
+       up->fcr |= UART_FCR_TRIGGER_1;
+}
+
 void
 serial8250_do_set_termios(struct uart_port *port, struct ktermios *termios,
                          const struct ktermios *old)
@@ -2710,13 +2728,7 @@ serial8250_do_set_termios(struct uart_port *port, struct ktermios *termios,
        uart_port_lock_irqsave(port, &flags);
 
        up->lcr = cval;                                 /* Save computed LCR */
-
-       if (up->capabilities & UART_CAP_FIFO && port->fifosize > 1) {
-               if (baud < 2400 && !up->dma) {
-                       up->fcr &= ~UART_FCR_TRIGGER_MASK;
-                       up->fcr |= UART_FCR_TRIGGER_1;
-               }
-       }
+       serial8250_set_trigger_for_slow_speed(port, termios, baud);
 
        /*
         * MCR-based auto flow control.  When AFE is enabled, RTS will be