[U-Boot] U-boot Porting

[Andreas Bießmann]

Dear Aaron Williams,

On 06.07.2012 01:52, Aaron Williams wrote:
> Hi Zahid,
> 
> I am in charge of U-Boot for OCTEON MIPS. I have not pushed the changes
> back upstream since the amount of code is enormous (over 430K lines of
> code!). Granted, a huge percentage of that is from generated register
> files but it is still a huge amount of code. Just the DRAM
> initialization code is 9600 lines of code for DDR2 and DDR3 support.
> 
> We also do things that no other architecture does with U-Boot such as we
> always run in TLB mapped memory. The code is available under GPL but you
> need to contact support at cavium.com. With the TLB mapping it no longer
> matters where U-Boot is loaded in memory. The same U-Boot binary image
> can start executing at any 64K flash boundary in the first 4MB of flash
> (so we support the same image as a failsafe and standard bootloader),
> any 4MB boundary in RAM (when booted over PCI or eJTAG) and out of L2
> cache (our top of trunk copies itself from flash to the L2 cache very
> early on to speed up memory initialization). The TLB mapping also allows
> U-Boot to be copied to the very top of memory since KSEG0 is rather
> limited to only 256MB. This is essential since we can support many GB of
> RAM which otherwise requires 64-bit addressing.
> 
> I need to push some of my changes back upstream since I have added some
> drivers for some temperature sensors, power monitors, fixed the AHCI
> driver and added a few features over the standard U-Boot (such as
> dynamically generated prompt support).

I would really like to see the whole stuff in mainline in favor of out
of tree patches maintained only inside Cavium.
Mainline U-Boot may also benefit from your generic changes and you will
get reviews for free.

Best regards

Andreas Bießmann