On Thu, 2014-01-23 at 11:13 -0700, Danny Gale wrote: > Hi Wolfgang, > > Thanks for your reply. My responses are inline below. > > On 1/22/2014 2:06 AM, Wolfgang Denk wrote: > > Dear Danny Gale, > > > > In message <52df18b3.1080...@coloradoengineeringinc.com> you wrote: > >> The T4240 on the T4QDS board is a PPC e6500 core (64 bit), but it is > >> configured in U-Boot as an e500 core, which is 32 bit. Why is this? > > Becuase it simply works :-) > > > >> Can it be updated to e6500? > > Yes - if you add support for 64 bit configurations in general, and > > for powerpc64 in particular. > I don't even have a sense for what would be involved here. How > fundamentally would the U-Boot code need to change?
The common U-Boot code should be more or less OK -- the armv8 target runs as 64-bit, and sandbox can as well. The PPC code is another matter, though. You'd need to hack up or replace a bunch of asm code at the least. > >> This leads directly into another question: can U-Boot be compiled and > >> run 64-bit? So far, I have been unable to make it work with a 64-bit > >> compiler. I'm running into these errors: > > Not out of the box. > > > > > > What is your actual reason for wanting to run a 64 bit boot loader? > My reason for wanting to run 64-bit is that this system has 12 GB of > RAM. Will 32-bit U-Boot be able to access and test more than 4 GB of RAM? 32-bit U-Boot can detect (or otherwise know about) and tell the OS about large amounts of RAM, but it can only directly access 2 GiB. -Scott _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
