Re: rock960c

[Trevor Woerner <twoerner@gmail.com>]

On Mon 2021-07-12 @ 07:54:44 AM, Peter Robinson wrote:
> On Tue, Jul 6, 2021 at 8:03 AM Trevor Woerner <twoerner@gmail.com> wrote:
> >
> > Hi,
> >
> > I was hoping that one day support would be added for the rockchip rock960c
> > board (from the 96boards series, https://www.96boards.org/product/rock960c/).
> > NOTE: this board is different from the rock960 board (aka rock960 a/b) that is
> > currently supported.
> >
> > Schematics and datasheets aren't easy to come by. A while back someone
> > mentioned that the only difference between the rock960 a/b and the rock960c is
> > that the rock960c uses different SDRAM (LPDDR4 instead of LPDDR3). Searching
> > around on the Internet it would appear that the rock960c uses the same SDRAM
> > as the rock-pi-4 devices (maybe?).
> 
> I don't think it has a USB-C port, nor a onboard eMMC, although from
> memory it does have a header.

It does have a USB-C port (although I'm using the separate 12V plug for power)
but you're right about the rest (it doesn't have onboard eMMC, but does have a
header if the user wants to populate one).

> > The actual SDRAM on the board is H9HCNNN4KUML-HRNMN, but I can't find a
> > datasheet for it anywhere, not even on Hynix's website.
> >
> > I tried creating a rock960c device by copying the rock960 things. The one
> > change I made was that my rk3399-rock960c-u-boot.dtsi file has:
> >
> >         #include "rk3399-sdram-lpddr4-100.dtsi"
> >
> > (which is what the rock-pi-4 is using) instead of:
> >
> >         #include "rk3399-sdram-lpddr3-2GB-1600.dtsi"
> 
> You'll probably need to add/update a DDR line in the config file as well.

Okay, I'll take a second look.

> > (which is what rk3399-rock960-u-boot.dtsi is using). Unfortunately this
> > doesn't succeed. The TPL is invoked, then there's nothing else on the console:
> >
> >         U-Boot TPL 2021.04 (Jun 30 2021 - 18:16:57)
> >
> > I then tried building and using the vendor-supplied u-boot fork for the
> > rock960c which is found here:
> >
> >         git://github.com/96rocks/u-boot.git
> >
> > but it is quite old (U-Boot 2017.09) and pre-dates the TPL/idbloader things.
> > If I understand things correctly, the vendor branch only builds u-boot and the
> > spl, I then need to mash in some sort of binary ddr file to the spl to get a
> > working first-stage bootloader (?). I'm unclear how to take the build output
> > from the vendor branch and create a working bootloader to load on my sdcard
> > (the only docs for the rk3399 in that branch are generic and don't refer to
> > things that come out of the build for the rock960c).
> 
> I personally wouldn't waste your time with the vendor one, I would
> think everything needed is already upstream for the core support.

Agreed. The vendor branch is so old I don't think it is useful anymore. Best
to just start with U-Boot master and tweak from there.

> > In any case, if anyone has any any tips etc I'd appreciate it :-)
> 
> There's not an upstream dts either, which probably isn't a big issue
> for the basics. I don't remember whether or not if I have a revC of
> these boards somewhere, I can't promise timing wise but if I get a
> moment I'll see if I can work out if I have one.

Sounds good, thanks! :-)