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    SubjectRe: [PATCH RFC 15/17] microblaze: Convert from _fdt_start to __dtb_start
    On 11/13/2013 11:19 AM, Michal Simek wrote:
    > On 11/12/2013 08:42 PM, Geert Uytterhoeven wrote:
    >> Kill the microblaze-specific __fdt_blob section, and start using
    >> .dtb.init.rodata from <asm-generic/sections.h> for built-in DTBs, like
    >> most other DT enabled architectures.
    >>
    >> Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
    >> Cc: Michal Simek <monstr@monstr.eu>
    >> Cc: Rob Herring <rob.herring@calxeda.com>
    >> Cc: microblaze-uclinux@itee.uq.edu.au
    >> Cc: devicetree@vger.kernel.org
    >> ---
    >> Untested, but the resulting vmlinux after "make simpleImage.system" looks
    >> sane.
    >>
    >> QUESTION: The padding of the DTB is gone, is this OK?
    >
    > Removing this kernel padding should be fine. I can't remember
    > why it was there from the beginning.

    I know why is this here. The reason is process how dtb is passed
    to the kernel via command line. head.S code just copy that dtb to
    the same location where compiled-in dts is expected and kernel
    doesn't need to care about position of dtb because this copy is
    done without MMU. And the full kernel is covered by 2 tlbs and
    we don't need to use another TLB for dtb mapping.

    It means pad matters a lot. Because u-boot ITS format doesn't use
    simpleImage target but the kernel need to have a space for copying
    dtb to this kernel location.

    Let me think about if there is an easy way to handle dtbs
    which are passed from bootloader.

    Thanks,
    Michal

    --
    Michal Simek, Ing. (M.Eng), OpenPGP -> KeyID: FE3D1F91
    w: www.monstr.eu p: +42-0-721842854
    Maintainer of Linux kernel - Microblaze cpu - http://www.monstr.eu/fdt/
    Maintainer of Linux kernel - Xilinx Zynq ARM architecture
    Microblaze U-BOOT custodian and responsible for u-boot arm zynq platform


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