Re: [PATCH] serial: core: Add support for dev_name:0.0 naming for kernel console

Jiri Slaby
2023-07-19T05:25:44Z

On 19. 07. 23, 7:15, Tony Lindgren wrote:
> With the serial core controller related changes we can now start
> addressing serial ports with dev_name:0.0 naming. The names are something
> like 00:04.0:0.0 on qemu, and 2800000.serial.0:0.0 on ARM for example.
>
> The dev_name is unique serial port hardware controller device name, also
> known as port->dev, and 0.0 are the serial core controller id and port id.
>
> Typically 0.0 are used for each controller and port instance unless the
> serial port hardware controller has multiple controllers or ports.
>
> Signed-off-by: Tony Lindgren <tony@atomide.com>
> ---
>
> Note that this depends on fix for serial core port ids patch
> "[PATCH] serial: core: Fix serial core port id to not use port->line"
>
> ---
> drivers/tty/serial/serial_core.c | 47 ++++++++++++++++++++++++++++++++
> 1 file changed, 47 insertions(+)
>
> diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
> --- a/drivers/tty/serial/serial_core.c
> +++ b/drivers/tty/serial/serial_core.c
> @@ -3322,6 +3322,49 @@ static int serial_core_port_device_add(struct serial_ctrl_device *ctrl_dev,
> return 0;
> }
>
> +/*
> + * Add preferred console if configured on kernel command line with naming
> + * "console=dev_name:0.0".
> + */
> +static int serial_core_add_preferred_console(struct uart_driver *drv,
> + struct uart_port *port)
> +{
> + char *port_match, *opt, *name;
> + int len, ret = 0;
> +
> + port_match = kasprintf(GFP_KERNEL, "console=%s:%i.%i",
> + dev_name(port->dev), port->ctrl_id,
> + port->port_id);
> + if (!port_match)
> + return -ENOMEM;
> +
> + opt = strstr(saved_command_line, port_match);
> + if (!opt)
> + goto free_port_match;
> +
> + len = strlen(port_match);
> +
> + if (strlen(opt) > len + 1 && opt[len] == ',')
> + opt += len + 1;
> + else
> + opt = NULL;
> +
> + name = kstrdup(drv->dev_name, GFP_KERNEL);

Why do you dup the name here?

> + if (!name) {
> + ret = -ENOMEM;
> + goto free_port_match;
> + }
> +
> + add_preferred_console(name, port->line, opt);
> +
> + kfree(name);

thanks,
--
js
suse labs