Re: [PATCH] serial: core: Fix serial core port id to not use port->line

[Andy Shevchenko]

On Wed, Jul 19, 2023 at 08:12:33AM +0300, Tony Lindgren wrote:
> The serial core port id should be serial core controller specific port
> instance, which is not always the port->line index.
> 
> For example, 8250 driver maps a number of legacy ports, and when a
> hardware specific device driver takes over, we typically have one
> driver instance for each port. Let's instead add port->port_id to
> keep track serial ports mapped to each serial core controller instance.
> 
> Currently this is only a cosmetic issue for the serial core port device
> names. The issue can be noticed looking at /sys/bus/serial-base/devices
> for example though. Let's fix the issue to avoid port addressing issues
> later on.

Good catch!
Reviewed-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>

> Fixes: 84a9582fd203 ("serial: core: Start managing serial controllers to enable runtime PM")
> Signed-off-by: Tony Lindgren <tony@xxxxxxxxxxx>
> ---
>  drivers/tty/serial/8250/8250_core.c  | 2 ++
>  drivers/tty/serial/serial_base_bus.c | 2 +-
>  include/linux/serial_core.h          | 1 +
>  3 files changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c
> --- a/drivers/tty/serial/8250/8250_core.c
> +++ b/drivers/tty/serial/8250/8250_core.c
> @@ -497,6 +497,7 @@ static struct uart_8250_port *serial8250_setup_port(int index)
>  
>  	up = &serial8250_ports[index];
>  	up->port.line = index;
> +	up->port.port_id = index;
>  
>  	serial8250_init_port(up);
>  	if (!base_ops)
> @@ -1040,6 +1041,7 @@ int serial8250_register_8250_port(const struct uart_8250_port *up)
>  			uart_remove_one_port(&serial8250_reg, &uart->port);
>  
>  		uart->port.ctrl_id	= up->port.ctrl_id;
> +		uart->port.port_id	= up->port.port_id;
>  		uart->port.iobase       = up->port.iobase;
>  		uart->port.membase      = up->port.membase;
>  		uart->port.irq          = up->port.irq;
> diff --git a/drivers/tty/serial/serial_base_bus.c b/drivers/tty/serial/serial_base_bus.c
> --- a/drivers/tty/serial/serial_base_bus.c
> +++ b/drivers/tty/serial/serial_base_bus.c
> @@ -136,7 +136,7 @@ struct serial_port_device *serial_base_port_add(struct uart_port *port,
>  	err = serial_base_device_init(port, &port_dev->dev,
>  				      &ctrl_dev->dev, &serial_port_type,
>  				      serial_base_port_release,
> -				      port->line);
> +				      port->port_id);
>  	if (err)
>  		goto err_put_device;
>  
> diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h
> --- a/include/linux/serial_core.h
> +++ b/include/linux/serial_core.h
> @@ -460,6 +460,7 @@ struct uart_port {
>  	int			(*iso7816_config)(struct uart_port *,
>  						  struct serial_iso7816 *iso7816);
>  	int			ctrl_id;		/* optional serial core controller id */
> +	int			port_id;		/* optional serial core port id */
>  	unsigned int		irq;			/* irq number */
>  	unsigned long		irqflags;		/* irq flags  */
>  	unsigned int		uartclk;		/* base uart clock */
> -- 
> 2.41.0

-- 
With Best Regards,
Andy Shevchenko