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serial: 8250: extract serial8250_initialize()

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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>
This commit is contained in:
Jiri Slaby (SUSE) 2025-06-11 12:03:02 +02:00 • committed by Greg Kroah-Hartman
parent a194597c0c
commit 795158691c
1 changed files with 50 additions and 53 deletions
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103
drivers/tty/serial/8250/8250_port.c
View file

@ -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