DMA isn’t just for the embedded world; it was once a big deal on computers, too. It’s just rarer these days due to security concerns and all that.

You can write DMA safely in Rust, but judging by the flippancy with which the author addresses safety concerns (where memory safety is the biggest security problem by far in modern software), I'm guessing his advice would be "Just write it in C/C++; it'll be fiiiiiiine."