Hi Nico
On 26. Jun 2018 12:56 nico.huber@secunet.com mailto:coreboot%40coreboot.org?Subject=Re%3A%20%5Bcoreboot%5D%20Porting%20Kabylake%20laptop&In-Reply-To=%3C7bc3873d-a7f3-1981-3b3b-fa6abc86bf8b%40secunet.com%3E wrote:
If you use the exact same processor SKU as the reference board: yes. Otherwise: no. Both the people who implemented FSP and who integrated it into coreboot were lazy: They could have provided defaults for all SKUs but didn't. If in doubt (and in case you don't have an NDA with Intel) better ask here what the right defaults are for your processor.
I have a i5-7200U. Intel has some datasheets available for Kabylake-U. Can they be used to get VR values?
- Can the laptop work properly without GPIO? I don't know if there is
a way to dump the GPIO config in vendor firmware on Kabylake.
What works with the reset default configuration and what not depends on each board. It is likely to boot in my experience. Have a look at `util/ inteltool/` in our source tree. It can dump the GPIO registers for Sun- rise Point (the 100-series PCH that comes with Skylake). The 200-series PCH should be the same, but if you have an SoC version of Kaby Lake (known as Kabylake-U / -Y / -R) things are different. I'll add Youness in CC who might have a patch for that.
Unfortunately inteltool doesn't support my PCH yet, probably because I have a Kabylake-U processor.
- Are there other settings that could damage the hardware?
I can't tell if that is the case for your board without knowing your board. Is it generally possible? yes. Though, it is unlikely that core- boot contains code that would harm your board. When you copy code for a reference board, you should also check the C code. It's not much and if there is something you don't understand, better ask. All the board- agnostic code should be safe (but there is no guarantee).
Do evaluation boards like KBL RVP8 have only board-agnostic code or do they also have some board-specific code?
And, as you need an FSP binary by Intel for Kaby Lake, it also has a huge amount of settings (over 700 if you count them individually (but they are actually grouped)). Some of these settings are overridden by coreboot (devicetree settings or static platform code). And their code quality is generally worse than coreboot's (maybe not over all but com- pared to coreboot). So I can't say if FSP doesn't do any harm (though unlikely, as it works for most everybody else so far). The binaries on Github likely have defaults for the non-SoC version btw. Alas, FSP is basically undocumented.
The FSP package from GitHub comes with config files for FSP. Do they need to be used or do only the settings in devicetree matter?
Thanks a lot for your help, it is very helpful.
Chris