On Mon, 13 Jun 2011 15:08:35 +0100, phil.edwor...@renesas.com wrote: > Hi Matthias, > >> >> What is the CONFIG_SYS_TEXT_BASE variable and how can >> >> I figure out what it should be? >> > >> > U-boot is typically stored in flash and one of the first things it >> does when executed is relocate to ram. CONFIG_SYS_TEXT_BASE is >> > the relocation >> > address. Typically, u-boot global data, heap and then stack is >> stored just below this. >> >> On ARM, CONFIG_SYS_TEXT_BASE is typically the base address of the >> image >> in flash. This is, on a system booting from NOR, the address of the >> first instruction which is fetched from the CPU. >> >> > Since u-boot is used to load some other program like the kernel, >> you need the u-boot relocation address to be out of the way of this. >> So, for the >> > boards I have seen (not arm), CONFIG_SYS_TEXT_BASE is set to the >> top of ram - 256KB, i.e. enough room for the u-boot image. >> >> The relocation address is dynamically calculated from a couple of >> (runtime) information and has nothing to do with >> CONFIG_SYS_TEXT_BASE. >> This is true for ARM and AFAIK for PPC. > > Thanks for the additional info - SH is a little different then! > > Phil
Thanks for the information. Since CONFIG_SYS_TEXT_BASE seems to be a critical value and isn't something that can be ignored, maybe it deserves an entry in the already helpful README. I'd write it myself but I'm not qualified. -Chris _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
