Re: [OSS-Tools] [PATCH v3 3/3] state: automatically find state.dtb in the ESP

[Ahmad Fatoum <a.fatoum@pengutronix.de>]

Hello Michael,

On 10.05.22 08:57, Michael Olbrich wrote:
> Systemd mounts the EFI System Partition (ESP) to /boot or /efi.
> So look there for the state.dtb when the devicetree in sysfs/procfs is
> not available.
> 
> This way barebox-state can be used on EFI systems without manually
> specifying the devicetree file.
> 
> Signed-off-by: Michael Olbrich <m.olbrich@pengutronix.de>
> ---
>  src/barebox-state.c | 24 ++++++++++++++++++++++++
>  1 file changed, 24 insertions(+)
> 
> diff --git a/src/barebox-state.c b/src/barebox-state.c
> index 334aed6f3d43..bf67340d4dc6 100644
> --- a/src/barebox-state.c
> +++ b/src/barebox-state.c
> @@ -342,6 +342,30 @@ struct state *state_get(const char *name, const char *filename, bool readonly, b
>  		}
>  	} else {
>  		root = of_read_proc_devicetree();
> +
> +		/* No device-tree in procfs / sysfs, try dtb file in the ESP */
> +		if (-PTR_ERR(root) == ENOENT) {
> +			const char *paths[] = {
> +				/* default mount paths used by systemd */
> +				"/boot/EFI/BAREBOX/state.dtb",
> +				"/efi/EFI/BAREBOX/state.dtb",

On my Debian, it is /boot/efi/EFI. Do you mind appending that one to the list? :-)

> +				NULL
> +			};
> +			void *fdt;
> +			int i;
> +
> +			for (i = 0; paths[i]; ++i) {
> +				fdt = read_file(paths[i], NULL);
> +				if (fdt)
> +					break;
> +			}
> +			if (fdt) {
> +				root = of_unflatten_dtb(fdt);
> +				free(fdt);
> +			}
> +			else
> +				root = ERR_PTR(-ENOENT);

This duplicates code in the first if clause. Can you move this into
a common helper (just a static function above state_get suffices)
and use it?

Thanks,
Ahmad

> +		}
>  		if (IS_ERR(root)) {
>  			pr_err("Unable to read devicetree. %s\n",
>  			       strerror(-PTR_ERR(root)));


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