Re: [PATCH v7 1/5] of/serial: move earlycon early_param handling to serial

[Greg Kroah-Hartman]

On Thu, Mar 31, 2016 at 04:40:23PM +0300, Aleksey Makarov wrote:
> From: Leif Lindholm <leif.lindholm@xxxxxxxxxx>
> 
> We have multiple "earlycon" early_param handlers - merge the DT one into
> the main earlycon one.  It's a cleanup that also will be useful
> to defer setting up DT console until ACPI/DT decision is made.
> 
> Rename the exported function to avoid clashing with the function from
> arch/microblaze/kernel/prom.c
> 
> Signed-off-by: Leif Lindholm <leif.lindholm@xxxxxxxxxx>
> Signed-off-by: Aleksey Makarov <aleksey.makarov@xxxxxxxxxx>
> Acked-by: Rob Herring <robh@xxxxxxxxxx>
> ---
>  drivers/of/fdt.c              | 11 +----------
>  drivers/tty/serial/earlycon.c |  2 +-
>  include/linux/of_fdt.h        |  2 ++
>  3 files changed, 4 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
> index 3349d2a..b50f775 100644
> --- a/drivers/of/fdt.c
> +++ b/drivers/of/fdt.c
> @@ -805,7 +805,7 @@ static inline void early_init_dt_check_for_initrd(unsigned long node)
>  
>  #ifdef CONFIG_SERIAL_EARLYCON
>  
> -static int __init early_init_dt_scan_chosen_serial(void)
> +int __init early_init_dt_scan_chosen_stdout(void)
>  {
>  	int offset;
>  	const char *p, *q, *options = NULL;
> @@ -849,15 +849,6 @@ static int __init early_init_dt_scan_chosen_serial(void)
>  	}
>  	return -ENODEV;
>  }
> -
> -static int __init setup_of_earlycon(char *buf)
> -{
> -	if (buf)
> -		return 0;
> -
> -	return early_init_dt_scan_chosen_serial();
> -}
> -early_param("earlycon", setup_of_earlycon);
>  #endif
>  
>  /**
> diff --git a/drivers/tty/serial/earlycon.c b/drivers/tty/serial/earlycon.c
> index 067783f..7aae655 100644
> --- a/drivers/tty/serial/earlycon.c
> +++ b/drivers/tty/serial/earlycon.c
> @@ -209,7 +209,7 @@ static int __init param_setup_earlycon(char *buf)
>  	 * don't generate a warning from parse_early_params() in that case
>  	 */
>  	if (!buf || !buf[0])
> -		return 0;
> +		return early_init_dt_scan_chosen_stdout();
>  
>  	err = setup_earlycon(buf);
>  	if (err == -ENOENT || err == -EALREADY)
> diff --git a/include/linux/of_fdt.h b/include/linux/of_fdt.h
> index 2fbe868..5cfe322 100644
> --- a/include/linux/of_fdt.h
> +++ b/include/linux/of_fdt.h
> @@ -63,6 +63,7 @@ extern int early_init_dt_scan_chosen(unsigned long node, const char *uname,
>  				     int depth, void *data);
>  extern int early_init_dt_scan_memory(unsigned long node, const char *uname,
>  				     int depth, void *data);
> +extern int early_init_dt_scan_chosen_stdout(void);
>  extern void early_init_fdt_scan_reserved_mem(void);
>  extern void early_init_fdt_reserve_self(void);
>  extern void early_init_dt_add_memory_arch(u64 base, u64 size);
> @@ -91,6 +92,7 @@ extern void early_get_first_memblock_info(void *, phys_addr_t *);
>  extern u64 of_flat_dt_translate_address(unsigned long node);
>  extern void of_fdt_limit_memory(int limit);
>  #else /* CONFIG_OF_FLATTREE */
> +static inline int early_init_dt_scan_chosen_stdout(void) { return -ENODEV; }

Doesn't this change the default logic?  Today you are returning 0 if you
don't have this config option set, and now you return -ENODEV, did you
test this out?

thanks,

greg k-h