[U-Boot] [PATCH 2/9] rockchip: support 4GB DRAM on 32bit systems

[Dr. Philipp Tomsich]

> On 26 Jul 2018, at 22:05, Carlo Caione <carlo at endlessm.com> wrote:
> 
> On Thu, 2018-07-26 at 15:59 +0200, Philipp Tomsich wrote:
>> The calculation in `rockchip_sdram_size` would overflow for 4GB on
>> 32bit systems (i.e. when PHYS_64BIT is not defined).
>> 
>> This makes the internal variables and the signature prototype use a
>> u64 to ensure that we can represent the 33rd bit (as in '4GB').
>> 
> 
> Hi Philipp,
> just to let you know that this is still not working on the veyron jerry
> chromebook with 4GB I have here (RK3288). The boot stops at:
> 
> U-Boot SPL 2018.07-00403-gdbe6ef8276 (Jul 26 2018 - 17:21:11 +0100)
> Trying to boot from SPI
> 
> U-Boot 2018.07-00403-gdbe6ef8276 (Jul 26 2018 - 17:21:11 +0100)
> 
> Model: Google Jerry
> DRAM:  0 Bytes
> 
> I'm still investigating why but for sure there are several points to
> fix to have a proper debug, see [0].

I reread ‘rockchip_sdram_size’ and it looks as if I forgot to mark the value
shifted to create chipsize_mb as ULL.  When looking at this code I had an
uneasy feeling that this might run into the C type rules (i.e. 1 will be a 32bit
integer and shifting it by 32 would result in 0), but I didn’t think that this
would ever be the case and that any 4GB DRAM setup would be made
up of multiple channels or of multiple ranks.

> 
> Also I was wondering if we should also fix get_effective_memsize() and
> gd->bd->bi_dram[].size
> 
> [0]https://gist.github.com/carlocaione/b93cfd9ee71e07fcf68d5c02256ff0fa
> 
> Cheers,
> 
> -- 
> Carlo Caione <carlo at endlessm.com>