> -----Original Message----- > From: Tabi Timur-B04825 [mailto:b04...@freescale.com] > Sent: den 21 september 2012 13:37 > To: Robert Thorhuus > Cc: Kumar Gala; u-boot@lists.denx.de > Subject: Re: [U-Boot] > arch/powerpc/lib/board.c:get_effective_memsize() for 4GB+ systems > > Robert Thorhuus wrote: > > > I really see the advantage of keeping this map you have. It is of > > course more compatible with different OSEs and you do not > need to do > > anything special with 32/64 bit cores. But at the same time > you never > > take advantage of a 64 bit core with this approach. > > U-Boot is a boot loader, not an operating system. What is > U-Boot supposed to do with more than 2GB of RAM? > > > How should I access my 24GB in U-Boot? > > You should not! > > > So really you are saying that I should have a 2GB map window in my > > 32-bit address space and then move this window depending on what > > memory I want to access? A bit cumbersome I must say. But ok. > > Again, you're doing the wrong thing with U-Boot. It's a boot loader. > It's supposed to find your OS, load it into memory, and then boot it. > > > How about the U-Boot relocation? > > > As I see the code, it is not easy to decide where it should > relocate. > > It will be either relocated to end of RAM or if we have > more than 4G > > it will be at 4GB end. > > It relocates to the end of RAM or the end of 2GB, whichever > is lower. It ignores all memory above 2GB. > > > What if you want to place U-Boot at 16MB for instance? Or if you do > > not want a memory map hole at 4GB just because U-Boot > doesn't handle > > more than that? > > Again, you're missing the point about U-boot. > > > Last AND least I just want to say I'm used to creating > memory maps in > > bootloader which holds for the OS. It seems the time has come to > > annihilate my illusion... > > Yes, please kill it with fire! > > -- > Timur Tabi > Linux kernel developer at Freescale >
Hello Timur! You really used the machine gun there ;) Ok. I'll just answer your 2GB+ usage question: Testing! No I will not be using much memory at all for functionality. But the memory needs to be tested. What is your proposal for that then? And I see U-Boot as the first software place for test and debug. Maybe I want to read out RAM contents? BR Robert _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
