Attention is currently required from: Alper Nebi Yasak, Arthur Heymans, Julius Werner, ron minnich.
Nico Huber has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/80372?usp=email )
Change subject: arch/io.h: Add port I/O functions to other architectures ......................................................................
Patch Set 5:
(1 comment)
File src/device/Kconfig:
https://review.coreboot.org/c/coreboot/+/80372/comment/402fac2e_77cae546 : PS5, Line 532: CPU communicate with peripheral devices over PCI I/O space.
Port I/O is a concept completely specific to the x86 architecture, it doesn't make sense on Arm. […]
There's definitely PCI hardware in the world that would need it. However, I couldn't tell if coreboot would ever see such real hardware, or only emulated one (and then we could just choose to emulate something else?).
Maybe we should make this a broader discussion about how much PCI we want to support on non-x86? AFAICT, qemu-aarch64, qcom and mtk already partially implement PCI i/o support. Should we move ahead or back? IMHO, it wouldn't be much of a burden to go ahead.
Julius, about the API, maybe you could try to see it more abstract like this: there's something that requires special instructions on x86, but can be done with MMIO on reasonable platforms. With this in mind would any- thing be wrong with the current API?