[PATCH 2/2] console: respect baudrate specified in device-tree stdout-path

[Sascha Hauer]

Hi Ahmad,

On Sat, Jun 19, 2021 at 05:26:54AM +0200, Ahmad Fatoum wrote:
> -static void console_set_stdoutpath(struct console_device *cdev)
> +static void console_set_stdoutpath(struct console_device *cdev, unsigned baudrate)
>  {
>  	int id;
>  	char *str;
> @@ -232,8 +232,7 @@ static void console_set_stdoutpath(struct console_device *cdev)
>  	if (id < 0)
>  		return;
>  
> -	str = basprintf("console=%s%d,%dn8", cdev->linux_console_name, id,
> -			  cdev->baudrate);
> +	str = basprintf("console=%s%d,%dn8", cdev->linux_console_name, id, baudrate);
>  
>  	globalvar_add_simple("linux.bootargs.console", str);
>  
> @@ -297,6 +296,7 @@ int console_register(struct console_device *newcdev)
>  	struct device_node *serdev_node = console_is_serdev_node(newcdev);
>  	struct device_d *dev = &newcdev->class_dev;
>  	int activate = 0, ret;
> +	unsigned baudrate = CONFIG_BAUDRATE;

You initialize baudrate to CONFIG_BAUDRATE here in order to use that as
a default, ...

>  
>  	if (!serdev_node && initialized == CONSOLE_UNINITIALIZED)
>  		console_init_early();
> @@ -327,11 +327,16 @@ int console_register(struct console_device *newcdev)
>  	if (serdev_node)
>  		return of_platform_populate(serdev_node, NULL, dev);
>  
> +	if (newcdev->dev && of_device_is_stdout_path(newcdev->dev, &baudrate)) {

...but of_device_is_stdout_path() unconditionally overwrites &baudrate...

> -int of_device_is_stdout_path(struct device_d *dev)
> +int of_device_is_stdout_path(struct device_d *dev, unsigned int *baudrate)
>  {
> -	if (!dev->device_node)
> -		return 0;
> +	unsigned int tmp;
> +
> +	if (!dev || !dev->device_node || dev->device_node != of_get_stdoutpath(&tmp))
> +		return false;
>  
> -	return dev->device_node == of_get_stdoutpath();
> +	*baudrate = tmp;

...here. This would break boards which don't have the baudrate given in
the devicetree.

Sascha

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