[U-Boot-Users] Coldfire 547x, Linux and big memory.

[Luigi 'Comio' Mantellini]

Hi List,
Hi Tsi-Ching Liew,

I'm using u-boot 1.3.2 (trunk) on my application in order to boot the
freescale linux kernel for mcf547x cpus. My application has a lot of
memory (256MB) and this causes difficulties to start the linux kernel.

The Head.S code of the mcf547x Linux Kernel allows a one-to-one TLB map
for the first 16MB of memory (mcf547x can use up to 1M for page). From
this observation it is mandatory that U-BOOT should call the kernel
allowing all structures (board descr., intrd, env and command line) onto
the first 16M of physical RAM.

The solutions can be:

- to use the env variables bootm_low = 0 and bootm_size = 0x1000000
(16M)
- modify the code of do_bootm function in order to limitate mem_size to
16M
- Pray the Freescale to modify the kernel code in order to use a better
and more flexible initialization code.

I'm studying for smart modifications for Kernel and U-Boot (that hasn't
guilt).


Best regards,

luigi

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