On Thu, Feb 3, 2011 at 1:01 AM, Aneesh V <ane...@ti.com> wrote: > Hi Albert, > > On Wednesday 02 February 2011 07:07 PM, Albert ARIBAUD wrote: >> Hi Aneesh, >> >> Le 02/02/2011 14:17, Aneesh V a écrit : >>> Hello Wolfgang, Albert, >>> >>> On Tuesday 01 February 2011 03:33 PM, Wolfgang Denk wrote: >>>> Dear Aneesh V, >>>> >>>> In message<4d47c1c9.1020...@ti.com> you wrote: >>>>> >>>>>> Why would that be necessary? Just put the BSS segment in SDRAM, and >>>>>> everything is fine, isn't it? >>>>> >>>>> SDRAM is initialized by the SPL. So, bss can not be initialized and >>>>> used until SDRAM initialization is complete. I would prefer to have >>>> >>>> Yes, this is normal. >>>> >>>>> rest of the bss in internal RAM so that it's available as soon as we >>>>> enter C code. >>>> >>>> Well, you probably have to decide if you want an easy solution with >>>> the restictions of the internal RAM size, or a somewhat more complex >>>> solution with much more powerful resources. >>> >>> I tried putting bss in SDRAM and it works for me. I just had to put a >>> couple of variables explicitly in .data section. >> >> You mean data that would have ended in BSS but that you moved to .data? >> Why? > > Yes. These are variables that otherwise would go to BSS. I do this > because I need them before SDRAM initialization. One of this is the gd > structure. I allocate gd structure in .data that is in IRAM. > Why I need gd before SDRAM? Because I try to initialize serial console > as early as possible and this code has some reference to gd. >
Which is a perfectly normal scenario and the way things have always been. There should have been no need to shuffle gd around because of console initialisation. And as I understand it, gd itself does not get statically 'allocated' in the u-boot image per-se (i.e. not in .data and not in .bss) - Only the pointer to it is allocated. In most arches, this pointer is itself not in .data or .bss but rather in a fixed reserved register. In the new x86 (final patches coming soon), the pointer is allocated in .data with a preset initialised value pointing into Cache-As-RAM (i.e. IRAM). Prior to relocation, the gd pointer variable points to somewhere in IRAM / CAR and after relocation, gd gets copied into the heap and the gd pointer adjusted to point to the new permanent copy. Regards, Graeme _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
