PPCBoot jumping to Linux.img - Powerpc

This is a discussion on PPCBoot jumping to Linux.img - Powerpc ; Hi, Linux.img image has a wrapper function around it so that it can be first uncompressed in the SDRAM and then start initializtion of the Kernel. The linux.img uncompressing will be done when the ppcboot will jump to linux.img image ...

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Thread: PPCBoot jumping to Linux.img

  1. PPCBoot jumping to Linux.img

    Hi,

    Linux.img image has a wrapper function around it so that it can be
    first uncompressed in the SDRAM and then start initializtion of the
    Kernel. The linux.img uncompressing will be done when the ppcboot will
    jump to linux.img image in the flash and then WHAT file and function
    is run in the kernel code to start kernel initliazation after it is
    uncompressed in the SDRAM ?


    Divyesh

  2. Re: PPCBoot jumping to Linux.img

    Hi Wolfgang,

    I am new to embedded linux. I have worked with Vxworks for a long
    time. I am using MPC8260 using Metrowerks development tool kit and it
    comes with PPCBoot. I followed the PPCBoot code all the way upto
    where it gets environment variable and passes it into run_command
    function to call the Kernel image physical address in the flash. I
    think that is where i am getting lost. I thought that linux.img image
    is same is Z image which gets wrapper added by my company to store it
    has a compressed image in the flash. I looked at head.s and it does
    lots of MPC8260 ADS board specific reinitialization and I do not
    understand, do i just not define the constant that includes that code
    then ? Please help me understand this little bit better. I would
    really appreciate it.

    Regards,
    Divyesh Patel
    Scientific Research Corporation

    Wolfgang Denk wrote in message news:...
    > dpatel@scires.com (Divyesh) writes:
    >
    > >Linux.img image has a wrapper function around it so that it can be

    >
    > I don't know what "Linux.img" is - it is not one of the standard
    > build targets in the Linux kernel Makefile. But yes, some image
    > formats contain a simple bootstrap loader.
    >
    > >first uncompressed in the SDRAM and then start initializtion of the
    > >Kernel. The linux.img uncompressing will be done when the ppcboot will

    >
    > This is not quite correct. If you use PPCBoot (or U-Boot as you
    > should do these days, as PPCBoot has been discontinued for a long
    > time ago) you will use a different image format, which does NOT
    > include such a wrapper. Instead, PPCBoot will perform the uncom-
    > pression directly.
    >
    > >jump to linux.img image in the flash and then WHAT file and function
    > >is run in the kernel code to start kernel initliazation after it is
    > >uncompressed in the SDRAM ?

    >
    > The kernel is started at it's entry point, "_start"
    > (see "arch/ppc/kernel/head*.S")
    >
    >
    > Wolfgang Denk


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