[PATCH v2] libfdt: Add support for using aliases in fdt_path_offset()

[David Gibson]

On Thu, Aug 14, 2008 at 07:51:47AM -0500, Kumar Gala wrote:
> If the path doesn't start with '/' check to see if it matches some alias
> under "/aliases" and substitute the matching alias value in the path
> and retry the lookup.
> 
> Signed-off-by: Kumar Gala <galak at kernel.crashing.org>
> ---
> 
> Fixed the bug pointed out by David Gibson and added tests.

Glad you spotted it in the end :)

[snip[]
> diff --git a/libfdt/fdt_ro.c b/libfdt/fdt_ro.c
> index ebd1260..2f3ff48 100644
> --- a/libfdt/fdt_ro.c
> +++ b/libfdt/fdt_ro.c
> @@ -139,8 +139,25 @@ int fdt_path_offset(const void *fdt, const char *path)
> 
>  	FDT_CHECK_HEADER(fdt);
> 
> -	if (*path != '/')
> -		return -FDT_ERR_BADPATH;
> +	/* see if we have an alias */
> +	if (*path != '/') {
> +		const char *q;
> +		int aliasoffset = fdt_path_offset(fdt, "/aliases");
> +
> +		if (aliasoffset < 0)
> +			return -FDT_ERR_BADPATH;
> +
> +		q = strchr(path, '/');
> +		if (!q)
> +			q = end;
> +
> +		p = fdt_getprop_namelen(fdt, aliasoffset, path, q - p, NULL);
> +		if (!p)
> +			return -FDT_ERR_BADPATH;
> +		offset = fdt_path_offset(fdt, p);
> +
> +		p = q;
> +	}

Much better.  It would be quite nice to have an explicit way of
retreiving the aliases too, but I can factor that out easily enough in
a later patch.

[snip]
> --- /dev/null
> +++ b/tests/aliases.dts
> @@ -0,0 +1,31 @@
> +/dts-v1/;
> +
> +/memreserve/ 0xdeadbeef00000000 0x100000;
> +/memreserve/ 123456789 010000;

I'd drop these /memreserve/s, they're not relevant to the test.

> +
> +/ {
> +	compatible = "test_tree1";
> +	prop-int = <0xdeadbeef>;
> +	prop-str = "hello world";

Likewise the various prop-int and prop-str properties.

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson