Re: [PATCH v1 3/6] serial: 8250: Make uart_match_port() a 8250 specific function

[Hugo Villeneuve]

Hi Uwe,

On Fri, 31 Jul 2026 11:39:06 +0200
Uwe Kleine-König <ukleinek@xxxxxxxxxx> wrote:

> The 8250 driver conglomerate is the only user of this function and in
> fact it already is 8250 specific as it uses hub6_match_port() which is
> defined in drivers/tty/serial/8250/8250_hub6.c unless the dummy
> implementation is in use.
> 
> Signed-off-by: Uwe Kleine-König <ukleinek@xxxxxxxxxx>
> ---
>  Documentation/driver-api/serial/driver.rst |  2 +-
>  drivers/tty/serial/8250/8250_core.c        | 27 +++++++++++++++++++++-
>  drivers/tty/serial/serial_core.c           | 27 ----------------------
>  include/linux/serial_core.h                |  2 --
>  4 files changed, 27 insertions(+), 31 deletions(-)
> 
> diff --git a/Documentation/driver-api/serial/driver.rst b/Documentation/driver-api/serial/driver.rst
> index c1db6a1a67c4..975b0ba53e98 100644
> --- a/Documentation/driver-api/serial/driver.rst
> +++ b/Documentation/driver-api/serial/driver.rst
> @@ -70,7 +70,7 @@ Other functions
>  
>  .. kernel-doc:: drivers/tty/serial/serial_core.c
>     :identifiers: uart_update_timeout uart_get_baud_rate uart_get_divisor
> -           uart_match_port uart_write_wakeup uart_register_driver
> +           uart_write_wakeup uart_register_driver
>             uart_unregister_driver uart_suspend_port uart_resume_port
>             uart_add_one_port uart_remove_one_port uart_console_write
>             uart_parse_earlycon uart_parse_options uart_set_options
> diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c
> index c0e8a4efbdcc..6059b84d8364 100644
> --- a/drivers/tty/serial/8250/8250_core.c
> +++ b/drivers/tty/serial/8250/8250_core.c
> @@ -630,6 +630,31 @@ EXPORT_SYMBOL(serial8250_resume_port);
>   */
>  static DEFINE_MUTEX(serial_mutex);
>  
> +/**
> + * serial8250_match_port - are the two ports equivalent?
> + * @port1: first port
> + * @port2: second port
> + *
> + * This utility function can be used to determine whether two uart_port
> + * structures describe the same port.
> + */
> +static bool serial8250_match_port(const struct uart_port *port1,
> +				  const struct uart_port *port2)
> +{
> +	if (port1->iotype != port2->iotype)
> +		return false;
> +	else if (port1->iotype == UPIO_PORT)
> +		return port1->iobase == port2->iobase;
> +	else if (port1->iotype == UPIO_HUB6)
> +		return hub6_match_port(port1, port2);
> +	else if (uart_iotype_mmio(port1->iotype))
> +		return port1->mapbase == port2->mapbase;
> +	else if (port1->iotype == UPIO_BUS)
> +		return true;

Since this is now moved to 8250-only context, UPIO_BUS case can
probably be dropped.


> +	else
> +		return false;
> +}
> +
>  static struct uart_8250_port *serial8250_find_match_or_unused(const struct uart_port *port)
>  {
>  	int i;
> @@ -638,7 +663,7 @@ static struct uart_8250_port *serial8250_find_match_or_unused(const struct uart_
>  	 * First, find a port entry which matches.
>  	 */
>  	for (i = 0; i < nr_uarts; i++)
> -		if (uart_match_port(&serial8250_ports[i].port, port))
> +		if (serial8250_match_port(&serial8250_ports[i].port, port))
>  			return &serial8250_ports[i];
>  
>  	/* try line number first if still available */
> diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
> index edd1e7be2a5c..8a6c53a9996e 100644
> --- a/drivers/tty/serial/serial_core.c
> +++ b/drivers/tty/serial/serial_core.c
> @@ -33,7 +33,6 @@
>  #include <linux/uaccess.h>
>  
>  #include "serial_base.h"
> -#include "8250/8250.h" /* For hub6_match_port() */
>  
>  /*
>   * This is used to lock changes in serial line configuration.
> @@ -3229,32 +3228,6 @@ static void serial_core_remove_one_port(struct uart_driver *drv,
>  	state->uart_port = NULL;
>  }
>  
> -/**
> - * uart_match_port - are the two ports equivalent?
> - * @port1: first port
> - * @port2: second port
> - *
> - * This utility function can be used to determine whether two uart_port
> - * structures describe the same port.
> - */
> -bool uart_match_port(const struct uart_port *port1,
> -		const struct uart_port *port2)
> -{
> -	if (port1->iotype != port2->iotype)
> -		return false;
> -	else if (port1->iotype == UPIO_PORT)
> -		return port1->iobase == port2->iobase;
> -	else if (port1->iotype == UPIO_HUB6)
> -		return hub6_match_port(port1, port2);
> -	else if (uart_iotype_mmio(port1->iotype))
> -		return port1->mapbase == port2->mapbase;
> -	else if (port1->iotype == UPIO_BUS)
> -		return true;
> -	else
> -		return false;
> -}
> -EXPORT_SYMBOL(uart_match_port);
> -
>  static struct serial_ctrl_device *
>  serial_core_get_ctrl_dev(struct serial_port_device *port_dev)
>  {
> diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h
> index c4cc4f66af4b..1659805e2233 100644
> --- a/include/linux/serial_core.h
> +++ b/include/linux/serial_core.h
> @@ -1137,8 +1137,6 @@ int uart_add_one_port(struct uart_driver *reg, struct uart_port *port);
>  void uart_remove_one_port(struct uart_driver *reg, struct uart_port *port);
>  int uart_read_port_properties(struct uart_port *port);
>  int uart_read_and_validate_port_properties(struct uart_port *port);
> -bool uart_match_port(const struct uart_port *port1,
> -		const struct uart_port *port2);
>  
>  /*
>   * Power Management
> -- 
> 2.55.0.11.g153666a7d9bb
> 
> 
> 


-- 
Hugo Villeneuve