RE: kernel startup

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Normally is it the uboot that uncompresses the kernel or the kernel

uncompress itself? 

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How would something compressed uncompress itself?  If u-boot is being

used 

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it will uncompress a compressed kernel and put the image at physical

0.

Small correction. Just like a self extracting binary, a kernel can have
a decompression code prepended to the start of kernel which can
decompress the 
Kernel.  This is how redboot for xscale is structured or syslinux /lilo
for x86. 

This also happens with the boot wrapper that is in arch/{ppc,powerpc}/boot

Although u-boot has simplified this step by doing the CRC checksum of
the
uiMage header as well as data and also decompress the kernel. Based on
load
address, entry point, the kernel can start executing.  

Now, whether cache is enable or not, MMU is enabled/disabled depends on
the
Developer. In current u-boot, the MMU is not used. I-Cache is On and
D-cache
is off.

I'm not sure what sub-arch we are talking about, but some do have the MMU 
on.

- kumar