first of all, i really wanted to figure all this out on my own but after looking through countless existing implementations and reading the bcm2835 arm peripherals, i still couldn't get to the quintessence of what it is i need to do.
for some context, right now i'm mainly working on a bootloader for the raspberry pi 3 in aarch64 assembly only. so far i have implemented uart, interrupts, timers, a framebuffer, etc. just to get a feeling for working on a bare metal target since i have never done that prior to this project. all that works just fine. ultimately though, i want it to be as small as possible, meaning only fullfilling the purpose of connecting to a local device and loading the kernel stored there into memory (currently implemented with uart).
since that really is all i want to do, i don't need a modular usb driver. i only care about sending frames and receiving frames. now the problem is that there seems to be a lot of configuration needed in different peripherals in order to achieve this and i can't figure out what i need and needn't do.
so to get to the point, what are the steps i have to take to make a minimal implementation?