PowerQUICC ProcessorsのトピックRe: Bundle kernel image,file system image and DTS

Bundle kernel image,file system image and DTS

ramakrishnakatt — Wed, 09 Apr 2014 13:11:02 GMT

Hi,

General uboot we load

tftp 1000000 /auto/tftp-blr-users1/ramakatt/test/uImage-p5040ds.bin

tftp 2000000 /auto/tftp-blr-users1/ramakatt/test/fsl-image-flash-p5040ds.ext2.gz.u-boot

tftp c00000 /auto/tftp-blr-users1/ramakatt/test/uImage-p5040ds.dtb

bootm 1000000 2000000 c00000

But I have to Bundle kernel image,file system image and DTS as single image. I have to load that single image from our custom boot loader. Is this possible?

If this possible please tell what all the steps has to be done to achieve this.

Thanks

Rama

Re: Bundle kernel image,file system image and DTS

bpe — Fri, 11 Apr 2014 14:31:01 GMT

Well, if you are designing a custom bootloader, you only need to know how to

inform the kernel of the location of the DTB and the root filesystem (initrd).

You then can pack everything in the manner you prefer, and unpack and transfer

the information mentioned above when you boot the kernel. The kernel expects

a pointer to the DTB in r3, the start address of the initrd in r4 and the end address of

initrd in r5. Take a look at arch/powerpc/kernel/head_fsl_booke.S for better

understanding.

If you wish to use a combined image format that already exists, take a look at

zImage. This format can combine all three components. Study the following

for more information:

Documentation/powerpc/bootwrapper.txt

arch/powerpc/boot/wrapper

All paths above are from the top level of the kernel source directory hierarchy.

I would also recommend to study Section 5 of ePAPR to understand how the bootloader,

the device tree and the kernel interact. This document can be downloaded from here:

http://www.freescale.com/infocenter/topic/QORIQSDK/2888193.html

Have a great day,
Platon

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Re: Bundle kernel image,file system image and DTS

scottwood — Fri, 11 Apr 2014 22:19:45 GMT

If you use zImage and the bootwrapper, then U-Boot will not see the device tree and will not make important fixups.

The right way to do this is with FIT images. See doc/uImage.FIT/ in the U-Boot source tree.