From: Lorenz Kolb <linuxppcemb@lkmail•de>
To: linuxppc-embedded@ozlabs•org
Subject: Re: small bootloader that passes arguments
Date: Mon, 12 Nov 2007 23:35:43 -0800 (PST) [thread overview]
Message-ID: <13721038.post@talk.nabble.com> (raw)
In-Reply-To: <13712778.post@talk.nabble.com>
Hi,
the normal operation of a bootloader is:
memcpy() -- copy the programme to boot to some new location maybe some
decoding done here, too
jump_to_addr() -- the easiest way to jump to some address in a higher level
language is to make a function call to some pointer. You can pass arguments
to this function, that is what bootloaders like u-boot do.
Personally I would recommand you to use some small first-stage-loader
loading U-Boot and make U-Boot do the rest. There is a U-Boot 1.1.4 port on
Xilinx' website for some Xilinx boards that can easily be adapted to Your
board (if it is no yet supported), I guess.
You can find Xilinx' U-Boot-"tree" here:
http://www.xilinx.com/ml410-p/81i_19.5/designs/u-boot.zip
Regards,
Lorenz Kolb
khollan wrote:
>
> Hi,
>
> I would like to create a small bootloader that is able to pass kernel
> arguments and boot a linux kernel. Im using a xilinx PPC, and have
> already booted a working kernel with a Xilinx provided XMD bootloader over
> USB. My main question is how does a bootloader pass these arguments to
> the kernel before booting it? Most specifically the root=/dev/xsa1
> command so I can tell it to either boot from compact flash or NFS.
>
> I really don't want to try and port U-boot since I don't need the bells
> and whistles and I want it to fit in the BRAM of the FPGA so it will load
> when I load the hardware configuration.
>
--
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prev parent reply other threads:[~2007-11-13 7:35 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-11-12 19:54 small bootloader that passes arguments khollan
2007-11-13 7:35 ` Lorenz Kolb [this message]
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