[U-Boot-Users] Boot the kernel from a JFFS2 filesystem

[Joakim Tjernlund]

> No. We're not talking about optimizing a few percent. When  you  have
> to  have  the  application  up and running within 5 or even 3 seconds
> after power-on you have to pay some price. You cannot afford  to  use
> compression,  and  even  a  highly optimized CRC over an uncompressed
> kernel image takes nearly as long as the uncompress would.
> 
> I think you cannot beat the speed of loading an  uncompressed  kernel
> image  from  flash (raw memory, no filesystem), with CRC verification
> turned off. If security plays a role, you  can  (and  will  have  to)
> verify the in-flash image later, when you are up and running :-) ]

Of course, but it's always nice to save a little time even if you can afford
a long boot time. You can probly also save some decompression time if you
choose a lower compression level(gzip -3) especially if port current zlib impl.
in linux which uses precompted lookup tables.

 > ...ummmm - please do'nt get me wrong: of course I do  appreciate  any
> optimizations  you  may  have  for  the CRC32 code. Just send a patch
> against the current source.

That was/is my plan, but since I am still in ppcboot and will be for some time I
offer to send it as is if someone is in a hurry and willing to do the integration with
u-boot. Just let me know.

      Jocke