[PATCH 6/8] sunxi: board: Set fdtfile to match the DT chosen by SPL

[André Przywara]

On 03/09/2020 06:07, Samuel Holland wrote:

Hi,

> Previously, fdtfile was always the value in CONFIG_DEFAULT_DEVICE_TREE.
> This meant that, regardless of the DT chosen by SPL (either by changing
> the header in the image or by the selection code at runtime), Linux
> always used the default DT.
> 
> By using the name from the SPL header (which, because of the previous
> commit, always matches the DT used by U-Boot proper), Linux also sees
> the same board as U-Boot/SPL, even if the boot script later loads a DT
> from disk.

I strongly frown upon proliferating the broken way of explicitly loading
a DT from somewhere, when the DT embedded in U-Boot should be all we
will ever need.
But making the selected DT available to U-Boot scripts doesn't really
hurt or prevent us from doing it properly, so:

> Signed-off-by: Samuel Holland <samuel at sholland.org>

One nit below, with that:
Reviewed-by: Andre Przywara <andre.przywara at arm.com>

Cheers,
Andre

> ---
>  board/sunxi/board.c | 11 +++++++++++
>  1 file changed, 11 insertions(+)
> 
> diff --git a/board/sunxi/board.c b/board/sunxi/board.c
> index eaa40a1ea96..5457b28e135 100644
> --- a/board/sunxi/board.c
> +++ b/board/sunxi/board.c
> @@ -870,6 +870,7 @@ static void setup_environment(const void *fdt)
>  
>  int misc_init_r(void)
>  {
> +	const char *spl_dt_name;
>  	uint boot;
>  
>  	env_set("fel_booted", NULL);
> @@ -888,6 +889,16 @@ int misc_init_r(void)
>  		env_set("mmc_bootdev", "1");
>  	}
>  
> +	/* Set fdtfile to match the FIT configuration chosen in SPL. */
> +	spl_dt_name = get_spl_dt_name();
> +	if (spl_dt_name) {
> +		char *prefix = IS_ENABLED(CONFIG_ARM64) ? "allwinner/" : "";
> +		char str[64];

The longest name (including the directory name) is 49 characters so far,
so let's hope that people don't go crazy with their DT names. Shall we
check the return value of snprintf() and at least complain? In contrast
to strncpy(), snprintf() is safe, but might still truncate the name.

Cheers,
Andre.

> +
> +		snprintf(str, sizeof(str), "%s%s.dtb", prefix, spl_dt_name);
> +		env_set("fdtfile", str);
> +	}
> +
>  	setup_environment(gd->fdt_blob);
>  
>  #ifdef CONFIG_USB_ETHER
>