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.
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.
(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.gitbut 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.
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.