pi5: peripheral address missing, and bcm_host_get_peripheral_address() broken about documentation HOT 9 CLOSED

On Pi 5 GPIO is controlled via the RP1. See the RP1 Peripherals document, https://datasheets.raspberrypi.com/rp1/rp1-peripherals.pdf.

from documentation.

@aallan i know most gpio is controlled by the RP1, and in this use-case, i didnt want an RP1 register
i was after the old ST_CLO register in the VPU timer, which i did find after some brute-forcing

but that does raise an interesting problem
with how the pi5 has re-arranged all of the SoC registers, and moved most stuff the user wants to the RP1, the old bcm_host_get_peripheral_address() is kind of useless
any offsets you would have done from there are now going to be wrong, no matter which base it returns

from documentation.

@pelwell thoughts here?

from documentation.

The source code for the bcm_host library lived in the userland repo, the README for which states:

This repo is ancient and deprecated.

It largely contains code using proprietary APIs to interface to the VideoCore firmware. We have since move to standard linux APIs.

V4L2, DRM/KMS and Mesa are the APIs you should be using.

The few useful tools from here (dtoverlay, dtmerge, vcmailbox, vcgencmd) have been moved to the raspberrypi/utils repo.

Code from here is no longer installed on latest RPiOS Bookworm images.

If you are using code from here you should rethink your solution.

Consider this repo closed.

There is no correct return value for bcm_host_get_peripheral_address() on Pi 5 other than NULL, but updating it would imply that the library still has a life.

from documentation.

@pelwell At that point I'm presuming this section https://www.raspberrypi.com/documentation/computers/raspberry-pi.html#peripheral-addresses needs rewriting?

from documentation.

I think we should just delete it. What do you think, @popcornmix ?

from documentation.

I agree. The repo the code is from has been closed, and I don't think the code is useful enough to resurrect it
(especially as most uses are unlikely to be applicable to Pi5 which uses RP1 for many equivalent peripherals).

from documentation.

Okay, I'll yank that entire section.

from documentation.

Removed entire section in ddfba6d. Will go to the live site next time I push to production.

from documentation.