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From: Grant Likely <grant.likely@secretlab.ca>
Date: Tue, 16 Nov 2010 17:16:14 -0700
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Subject: Re: [PATCH 2/5] of/fdt: add kernel command line option for dtb_compat
	string
To: dirk.brandewie@gmail.com
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On Tue, Nov 16, 2010 at 3:41 PM,  <dirk.brandewie@gmail.com> wrote:
> From: Dirk Brandewie <dirk.brandewie@gmail.com>
>
> Adds a kernel command line option "dtb_compat=3D<string>" and functions
> for architecture/platform specific code to retrieve the command line
> string and locate the compatible DTB linked into the kernel
>
> of_flat_dt_get_dtb_compatible_string() returns a pointer string passed
> from the command line or a pointer to an empty string.
>
> of_flat_dt_find_compatible_dtb() returns a pointer to a DTB that is
> compatible with the "compatible" string or a NULL pointer if no
> matching DTB is present.
>
> Signed-off-by: Dirk Brandewie <dirk.brandewie@gmail.com>
> ---
[...]
> +void __init *of_flat_dt_find_compatible_dtb(char *name)
> +{
> + =A0 =A0 =A0 void *rc =3D NULL;
> + =A0 =A0 =A0 unsigned long root, size;
> + =A0 =A0 =A0 struct boot_param_header =A0*orig_initial_boot_params;
> + =A0 =A0 =A0 uint8_t *blob;
> +
> + =A0 =A0 =A0 orig_initial_boot_params =3D initial_boot_params;
> + =A0 =A0 =A0 blob =3D __dtb_start;
> + =A0 =A0 =A0 initial_boot_params =3D (struct boot_param_header *)blob;
> +
> + =A0 =A0 =A0 while (blob < __dtb_end &&
> + =A0 =A0 =A0 =A0 =A0 =A0 =A0 (be32_to_cpu(initial_boot_params->magic) =
=3D=3D OF_DT_HEADER)) {

The kernel needs to complain *loudly* if this occurs because it
represents a bug.  I'm tempted to say use BUG, but that would halt the
kernel and prevent any possibility of kernel log output.  WARN_ON() is
probably best.

g.