I know there was an armv5 and armmv6 data sheet for this kind of thing, but there is none for the armv8, at least no publicly given. I went through: https://people-mozilla.org/~sstangl/arm/AArch64-Reference-Manual.pdf
I didn't actually read through all of it, but parsing things like: System timer, clock, peripherals, base address... is not giving me any satisfactory results.
All I want is a list of base addresses telling me what the base peripheral address is, and what the system clock's relative address is, and what the mailbox relative address is... and any and all other memory mapped peripherals.
The ARM Architecture Reference Manual is not where the peripherals or the memory map are described. ARM is not a chip, it is a licensed processor core IP built into chips by various licencee manufacturers who implement their own peripheral designs around it.
Broadcom provide the SoC for RPi, and it is a proprietary chip used internally by Broadcom, so that publish limited public data. The published Broadcom peripheral documentation refers to the RPi1's BCM2835 but is mostly identical to the RPi2 BCM2836 and RPi3 BCM2387 with respect to the peripheral set.