serial: 8250: extract serial8250_initialize()

serial8250_do_startup() initializes the ports in the middle of the
function. This code can be separated to serial8250_initialize(), so that
serial8250_do_startup() can be readable again.

Signed-off-by: "Jiri Slaby (SUSE)" <jirislaby@kernel.org>
Link: https://lore.kernel.org/r/20250611100319.186924-17-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 5466286bb44fc9bb69a150dc311c296fde9669af..6851c197b31de28188c5b97d90df833e76269b94 100644 (file)
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -2247,13 +2247,59 @@ static void serial8250_THRE_test(struct uart_port *port)
                up->bugs |= UART_BUG_THRE;
 }
 
-int serial8250_do_startup(struct uart_port *port)
+static void serial8250_initialize(struct uart_port *port)
 {
        struct uart_8250_port *up = up_to_u8250p(port);
        unsigned long flags;
-       unsigned char iir;
+       bool lsr_TEMT, iir_NOINT;
+
+       serial_port_out(port, UART_LCR, UART_LCR_WLEN8);
+
+       uart_port_lock_irqsave(port, &flags);
+       if (port->flags & UPF_FOURPORT) {
+               if (!port->irq)
+                       port->mctrl |= TIOCM_OUT1;
+       } else {
+               /* Most PC uarts need OUT2 raised to enable interrupts. */
+               if (port->irq)
+                       port->mctrl |= TIOCM_OUT2;
+       }
+
+       serial8250_set_mctrl(port, port->mctrl);
+
+       /*
+        * Serial over Lan (SoL) hack:
+        * Intel 8257x Gigabit ethernet chips have a 16550 emulation, to be used for Serial Over
+        * Lan.  Those chips take a longer time than a normal serial device to signalize that a
+        * transmission data was queued. Due to that, the above test generally fails. One solution
+        * would be to delay the reading of iir. However, this is not reliable, since the timeout is
+        * variable. So, let's just don't test if we receive TX irq.  This way, we'll never enable
+        * UART_BUG_TXEN.
+        */
+       if (!(port->quirks & UPQ_NO_TXEN_TEST)) {
+               /* Do a quick test to see if we receive an interrupt when we enable the TX irq. */
+               serial_port_out(port, UART_IER, UART_IER_THRI);
+               lsr_TEMT = serial_port_in(port, UART_LSR) & UART_LSR_TEMT;
+               iir_NOINT = serial_port_in(port, UART_IIR) & UART_IIR_NO_INT;
+               serial_port_out(port, UART_IER, 0);
+
+               if (lsr_TEMT && iir_NOINT) {
+                       if (!(up->bugs & UART_BUG_TXEN)) {
+                               up->bugs |= UART_BUG_TXEN;
+                               dev_dbg(port->dev, "enabling bad tx status workarounds\n");
+                       }
+               } else {
+                       up->bugs &= ~UART_BUG_TXEN;
+               }
+       }
+
+       uart_port_unlock_irqrestore(port, flags);
+}
+
+int serial8250_do_startup(struct uart_port *port)
+{
+       struct uart_8250_port *up = up_to_u8250p(port);
        int retval;
-       u16 lsr;
 
        if (!port->fifosize)
                port->fifosize = uart_config[port->type].fifo_size;
@@ -2310,56 +2356,7 @@ int serial8250_do_startup(struct uart_port *port)
 
        up->ops->setup_timer(up);
 
-       /*
-        * Now, initialize the UART
-        */
-       serial_port_out(port, UART_LCR, UART_LCR_WLEN8);
-
-       uart_port_lock_irqsave(port, &flags);
-       if (up->port.flags & UPF_FOURPORT) {
-               if (!up->port.irq)
-                       up->port.mctrl |= TIOCM_OUT1;
-       } else
-               /*
-                * Most PC uarts need OUT2 raised to enable interrupts.
-                */
-               if (port->irq)
-                       up->port.mctrl |= TIOCM_OUT2;
-
-       serial8250_set_mctrl(port, port->mctrl);
-
-       /*
-        * Serial over Lan (SoL) hack:
-        * Intel 8257x Gigabit ethernet chips have a 16550 emulation, to be
-        * used for Serial Over Lan.  Those chips take a longer time than a
-        * normal serial device to signalize that a transmission data was
-        * queued. Due to that, the above test generally fails. One solution
-        * would be to delay the reading of iir. However, this is not
-        * reliable, since the timeout is variable. So, let's just don't
-        * test if we receive TX irq.  This way, we'll never enable
-        * UART_BUG_TXEN.
-        */
-       if (!(up->port.quirks & UPQ_NO_TXEN_TEST)) {
-               /*
-                * Do a quick test to see if we receive an interrupt when we
-                * enable the TX irq.
-                */
-               serial_port_out(port, UART_IER, UART_IER_THRI);
-               lsr = serial_port_in(port, UART_LSR);
-               iir = serial_port_in(port, UART_IIR);
-               serial_port_out(port, UART_IER, 0);
-
-               if (lsr & UART_LSR_TEMT && iir & UART_IIR_NO_INT) {
-                       if (!(up->bugs & UART_BUG_TXEN)) {
-                               up->bugs |= UART_BUG_TXEN;
-                               dev_dbg(port->dev, "enabling bad tx status workarounds\n");
-                       }
-               } else {
-                       up->bugs &= ~UART_BUG_TXEN;
-               }
-       }
-
-       uart_port_unlock_irqrestore(port, flags);
+       serial8250_initialize(port);
 
        /*
         * Clear the interrupt registers again for luck, and clear the