I tried the program, and it partially works. It toggles pin 33 (GPIO_PE6), but only that pin. Much confusion because the program is hardcoded to toggle GPIO address 0x6000d100. But this address is not listed in table 26 of the “Tegra X1 (SoC) Technical Reference Manual”. Table 26’s address for Pin 33 (GPIO_PE6) is 0x700009c8. In fact all the register addresses start with 0x70000. So I’m surprised the program works. Or maybe the program does some shifting. The low level programming is difficult to follow.
It’s unfortunate that NVIDIA does not have a working Direct Register Access (DRA) library as an alternative to the slow filesys approach. Or perhaps NVIDIA is working on it? A jetson version of WiringPi would be huge for the community.