[Arm-netbook] RAM, uboot

[lkcl luke]

On Sat, May 12, 2012 at 12:07 PM, David Given <dg at cowlark.com> wrote:
> On 10/05/12 21:35, David Given wrote:
> [...]
>> 448? Where's the other 64MB going?
>
> Well, I figured this out. From arch/arm/mach-sun4i/core.c, line 407, in
> the code that sets up the initial memory:
>
>    size = DRAMC_get_dram_size();
>
>    if (size <= 512) {
>            mi->nr_banks=1;
>            mi->bank[0].start = 0x40000000;
>            mi->bank[0].size = SZ_1M * (size - 64);
>    } else {
>    ...
>
> So it's deliberately reducing the DRAM area by 64MB. I have no idea why.
> I tried changing the amount it's reduced by, and all that happens is
> that the kernel fails to start, hanging after the "Memory Policy..." line.
>
> Can anyone shed any light on this?

 well.... the "policy decision" is made on the line "size =
DRAMC_get_dram_size()", so if you grep for DRAMC_get_dram_size() in
other places you might find the locations where the reserved RAM is
actually being used, maybe, maybe not.

 the other thing to try is to track down what the variable "mi" is,
and grep for that as well.

 l.