After commit 795158691cc0 ("serial: 8250: extract
serial8250_initialize()"), split serial8250_initialize() even more --
the mctrl part of this code can be separated into
serial8250_init_mctrl() -- done now.

Signed-off-by: Jiri Slaby (SUSE) <jirislaby@kernel.org>
Suggested-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
---
[v2]
* use port-> directly.
* do not remove curly braces.
Both rebase errors -- noticed by Andy.
---
 drivers/tty/serial/8250/8250_port.c | 21 +++++++++++++--------
 1 file changed, 13 insertions(+), 8 deletions(-)

diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
index 48c30e158cb8..0f85a2f292fc 100644
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -2216,15 +2216,8 @@ static void serial8250_THRE_test(struct uart_port *port)
 		up->bugs |= UART_BUG_THRE;
 }
 
-static void serial8250_initialize(struct uart_port *port)
+static void serial8250_init_mctrl(struct uart_port *port)
 {
-	struct uart_8250_port *up = up_to_u8250p(port);
-	unsigned long flags;
-	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;
@@ -2235,6 +2228,18 @@ static void serial8250_initialize(struct uart_port *port)
 	}
 
 	serial8250_set_mctrl(port, port->mctrl);
+}
+
+static void serial8250_initialize(struct uart_port *port)
+{
+	struct uart_8250_port *up = up_to_u8250p(port);
+	unsigned long flags;
+	bool lsr_TEMT, iir_NOINT;
+
+	serial_port_out(port, UART_LCR, UART_LCR_WLEN8);
+
+	uart_port_lock_irqsave(port, &flags);
+	serial8250_init_mctrl(port);
 
 	/*
 	 * Serial over Lan (SoL) hack:
-- 
2.50.0

On Tue, Jun 24, 2025 at 10:06:37AM +0200, Jiri Slaby (SUSE) wrote:
> After commit 795158691cc0 ("serial: 8250: extract
> serial8250_initialize()"), split serial8250_initialize() even more --
> the mctrl part of this code can be separated into
> serial8250_init_mctrl() -- done now.

Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

-- 
With Best Regards,
Andy Shevchenko

On Tue, 24 Jun 2025, Jiri Slaby (SUSE) wrote:

> After commit 795158691cc0 ("serial: 8250: extract
> serial8250_initialize()"), split serial8250_initialize() even more --
> the mctrl part of this code can be separated into
> serial8250_init_mctrl() -- done now.
> 
> Signed-off-by: Jiri Slaby (SUSE) <jirislaby@kernel.org>
> Suggested-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>

Heh, I didn't even realize I was suggesting this :-D but it's good 
nonetheless.

Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>

> Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
> ---
> [v2]
> * use port-> directly.
> * do not remove curly braces.
> Both rebase errors -- noticed by Andy.
> ---
>  drivers/tty/serial/8250/8250_port.c | 21 +++++++++++++--------
>  1 file changed, 13 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
> index 48c30e158cb8..0f85a2f292fc 100644
> --- a/drivers/tty/serial/8250/8250_port.c
> +++ b/drivers/tty/serial/8250/8250_port.c
> @@ -2216,15 +2216,8 @@ static void serial8250_THRE_test(struct uart_port *port)
>  		up->bugs |= UART_BUG_THRE;
>  }
>  
> -static void serial8250_initialize(struct uart_port *port)
> +static void serial8250_init_mctrl(struct uart_port *port)
>  {
> -	struct uart_8250_port *up = up_to_u8250p(port);
> -	unsigned long flags;
> -	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;
> @@ -2235,6 +2228,18 @@ static void serial8250_initialize(struct uart_port *port)
>  	}
>  
>  	serial8250_set_mctrl(port, port->mctrl);
> +}
> +
> +static void serial8250_initialize(struct uart_port *port)
> +{
> +	struct uart_8250_port *up = up_to_u8250p(port);
> +	unsigned long flags;
> +	bool lsr_TEMT, iir_NOINT;
> +
> +	serial_port_out(port, UART_LCR, UART_LCR_WLEN8);
> +
> +	uart_port_lock_irqsave(port, &flags);
> +	serial8250_init_mctrl(port);
>  
>  	/*
>  	 * Serial over Lan (SoL) hack:
> 

-- 
 i.

On Tue, 24 Jun 2025, Ilpo Järvinen wrote:

> On Tue, 24 Jun 2025, Jiri Slaby (SUSE) wrote:
> 
> > After commit 795158691cc0 ("serial: 8250: extract
> > serial8250_initialize()"), split serial8250_initialize() even more --
> > the mctrl part of this code can be separated into
> > serial8250_init_mctrl() -- done now.
> > 
> > Signed-off-by: Jiri Slaby (SUSE) <jirislaby@kernel.org>
> > Suggested-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
> 
> Heh, I didn't even realize I was suggesting this :-D but it's good 
> nonetheless.
> 
> Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
> 
> > Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
> > ---
> > [v2]
> > * use port-> directly.
> > * do not remove curly braces.
> > Both rebase errors -- noticed by Andy.
> > ---
> >  drivers/tty/serial/8250/8250_port.c | 21 +++++++++++++--------
> >  1 file changed, 13 insertions(+), 8 deletions(-)
> > 
> > diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
> > index 48c30e158cb8..0f85a2f292fc 100644
> > --- a/drivers/tty/serial/8250/8250_port.c
> > +++ b/drivers/tty/serial/8250/8250_port.c
> > @@ -2216,15 +2216,8 @@ static void serial8250_THRE_test(struct uart_port *port)
> >  		up->bugs |= UART_BUG_THRE;
> >  }
> >  
> > -static void serial8250_initialize(struct uart_port *port)
> > +static void serial8250_init_mctrl(struct uart_port *port)
> >  {
> > -	struct uart_8250_port *up = up_to_u8250p(port);
> > -	unsigned long flags;
> > -	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) {

I should have also added what I meant with my earlier suggestion. AFAICT, 
this UPF_FOURPORT thing can only occur if SERIAL_8250_FOURPORT is enabled.

The challenge obviously are the if/else constructs but there are a few 
places that do port->flags & UPF_FOURPORT specific thing and something 
else otherwise. That hw-specific code could be placed into the hw-specific 
8250_fourport.c file if the hw-specific function is made to return true 
if it did match, and the generic code runs otherwise.

I also have no idea why serial/sunsu.c checks UPF_FOURPORT, perhaps that's 
copy-paste in action. :-)

> >  		if (!port->irq)
> >  			port->mctrl |= TIOCM_OUT1;
> > @@ -2235,6 +2228,18 @@ static void serial8250_initialize(struct uart_port *port)
> >  	}
> >  
> >  	serial8250_set_mctrl(port, port->mctrl);
> > +}
> > +
> > +static void serial8250_initialize(struct uart_port *port)
> > +{
> > +	struct uart_8250_port *up = up_to_u8250p(port);
> > +	unsigned long flags;
> > +	bool lsr_TEMT, iir_NOINT;
> > +
> > +	serial_port_out(port, UART_LCR, UART_LCR_WLEN8);
> > +
> > +	uart_port_lock_irqsave(port, &flags);
> > +	serial8250_init_mctrl(port);
> >  
> >  	/*
> >  	 * Serial over Lan (SoL) hack:
> > 
> 
> 

-- 
 i.

On 24. 06. 25, 13:15, Ilpo Järvinen wrote:
> On Tue, 24 Jun 2025, Ilpo Järvinen wrote:
> 
>> On Tue, 24 Jun 2025, Jiri Slaby (SUSE) wrote:
>>
>>> After commit 795158691cc0 ("serial: 8250: extract
>>> serial8250_initialize()"), split serial8250_initialize() even more --
>>> the mctrl part of this code can be separated into
>>> serial8250_init_mctrl() -- done now.
>>>
>>> Signed-off-by: Jiri Slaby (SUSE) <jirislaby@kernel.org>
>>> Suggested-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
>>
>> Heh, I didn't even realize I was suggesting this :-D but it's good
>> nonetheless.
>>
>> Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
>>
>>> Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
>>> ---
>>> [v2]
>>> * use port-> directly.
>>> * do not remove curly braces.
>>> Both rebase errors -- noticed by Andy.
>>> ---
>>>   drivers/tty/serial/8250/8250_port.c | 21 +++++++++++++--------
>>>   1 file changed, 13 insertions(+), 8 deletions(-)
>>>
>>> diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
>>> index 48c30e158cb8..0f85a2f292fc 100644
>>> --- a/drivers/tty/serial/8250/8250_port.c
>>> +++ b/drivers/tty/serial/8250/8250_port.c
>>> @@ -2216,15 +2216,8 @@ static void serial8250_THRE_test(struct uart_port *port)
>>>   		up->bugs |= UART_BUG_THRE;
>>>   }
>>>   
>>> -static void serial8250_initialize(struct uart_port *port)
>>> +static void serial8250_init_mctrl(struct uart_port *port)
>>>   {
>>> -	struct uart_8250_port *up = up_to_u8250p(port);
>>> -	unsigned long flags;
>>> -	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) {
> 
> I should have also added what I meant with my earlier suggestion. AFAICT,
> this UPF_FOURPORT thing can only occur if SERIAL_8250_FOURPORT is enabled.
> 
> The challenge obviously are the if/else constructs but there are a few
> places that do port->flags & UPF_FOURPORT specific thing and something
> else otherwise. That hw-specific code could be placed into the hw-specific
> 8250_fourport.c file if the hw-specific function is made to return true
> if it did match, and the generic code runs otherwise.

So you can brew a patch for this, right :)? Every time I read some code 
the same you describe, I end up with 10+ patches. I don't want for now :P.

> I also have no idea why serial/sunsu.c checks UPF_FOURPORT, perhaps that's
> copy-paste in action. :-)

Yes, AFAI looked, it was during the switch of sunsu to serial driver. If 
you feel confident (it really appears apparent), drop that too ;).

thanks,
-- 
js
suse labs