There is a lot of documentation for the JTX1…some of it covers booting, but developing for a driver in u-boot is going to need a lot of trial and error. It is likely you would need at least some minimal knowledge of registers, although I don’t think you’d need to be an expert at it. Keep in mind you may need to understand the ethernet hardware as well, not just the Tegra X1 (though the example driver may help a lot there).
The following may be useful:
[url]ftp://download.nvidia.com/tegra-public-appnotes/index.html[/url] (an index into some docs)
[url]http://http.download.nvidia.com/tegra-public-appnotes/t210-nvtboot-flow.html[/url] (how it all starts…listed in the index above)
[url]https://github.com/u-boot/u-boot/blob/master/doc/README.distro[/url] (search for “network”)
For ARMv8/ARMv8-A, create a free login here:
[url]Documentation – Arm Developer
…see Cortex-A series (left column), then Cortex A-57 (this is the ARMv8-A 64-bit architecture; ARMv8 without the “-A” is a subset of this and covers the 32-bit compatibility mode)
There is some documentation with the L4T download page as well. Additional documentation (the forum doesn’t work with this kind of URL, you’ll have to copy the correct part of the URL and paste it into your browser):
[url]https://developer.nvidia.com/embedded/downloads#?tx=$product,jetson_tx1[/url]