[U-Boot] [help] how does u-boot passing ``fdt'' to linux kernel & where is cmd_line?

[Baojun Wang]

Thank you very much, also found the method is documented the new u-boot wiki.

  Best Regards,
Wang


On Tue, Jul 14, 2009 at 7:24 PM, Detlev Zundel<dzu at denx.de> wrote:
> Hi Wang,
>
>>>> the code is from arch/powerpc/boot/cuboot-bamboo.c, and the kernel is
>>>> 2.6.30.1, the boot image I'm using is something like cuImage.bamboo, I
>>>> checked zImage.ld.S, and found that when we're running cuImage.bamboo,
>>>> we actually fall into arch/powerpc/boot/crt0.S:_zimage_start(), which
>>>> will call platform_init() and then bamboo_init() finally. but sounds
>>>> like if we passing r3 as fdt, then the code (platform_init, etc.., and
>>>> even arch/powerpc/kernel/head_xxx.S start() function, only comments,
>>>> though) is actually wrong, isn't it? Thank you very much for help.
>>>
>>> This is the boot wrapper code only used if you are trying to boot a new
>>> kernel w/an old u-boot.  If you are using a current u-boot you should just
>>> be using a plain old uImage as produced by the kernel build.
>>
>> do you mean the default ``uImage'' file? I'm using u-boot-2009.06, and
>> I can boot successfully with cuImage.mpc8548cds (I'm actually working
>> on a mpc8548 cds board), but unable to boot ``uImage'', I'm sure the
>> ``vmlinux'' is the same.
>
> Booting such a new kernel, you'll need to pass an adress of an fdt too:
>
> => help bootm
> bootm [addr [arg ...]]
>    - boot application image stored in memory
>    passing arguments 'arg ...'; when booting a Linux kernel,
>    'arg' can be the address of an initrd image
>    When booting a Linux kernel which requires a flat device-tree
>    a third argument is required which is the address of the
>    device-tree blob. To boot that kernel without an initrd image,
>    use a '-' for the second argument. If you do not pass a third
>    a bd_info struct will be passed instead
>
> So try "bootm <kernel> - <fdt>"
>
> Cheers
>  Detlev
>
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