asmc: add MMIO backend for T2 Macs
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Authored by guest-seuros on Tue, May 19, 10:13 AM.

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adrian
ngie

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rGa48b900300eb: asmc: add MMIO backend for T2 Macs

Summary

T2 Macs (2018+) expose the SMC via memory-mapped registers instead of
I/O ports. Add asmcmmio.c/asmcmmio.h implementing the MMIO transport:
key read/write, getinfo, getbyindex, and a poll-based wait with
exponential backoff.

The driver probes for MMIO at attach time by checking the LDKN firmware
version key; if MMIO is available it is used, otherwise the standard
I/O port backend is used.

T2 fan speeds use IEEE 754 floats instead of fpe2 fixed-point.
Per-fan manual mode uses F%dMd keys instead of the FS! bitmask.
Battery charge limit is exposed via dev.asmc.N.battery_charge_limit.

Tested on:

MacBookPro16,2 (A2251, iBridge2,10)
MacBookPro15,4 (A2159, iBridge2,8)
MacBookAir8,2  (A1932, iBridge2,5)
Mac mini 8,1   (A1993, iBridge2,7)
iMac20,2       (A2115, iBridge2,16)
iMacPro1,1     (A1862, iBridge1,1)

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Repository

rG FreeBSD src repository

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Event Timeline

guest-seuros created this revision.Tue, May 19, 10:13 AM

Herald added a subscriber: imp. · View Herald TranscriptTue, May 19, 10:13 AM

guest-seuros requested review of this revision.Tue, May 19, 10:13 AM

Harbormaster completed remote builds in B73216: Diff 178079.Tue, May 19, 10:13 AM

adrian added projects: drivers, apple (x86).Mon, May 25, 2:57 PM

adrian added a child revision: D57087: nvme: add Apple T2 ANS2 NVMe quirks.Tue, May 26, 3:45 AM

This looks fine, we can refactor it further later!

Did you test this on pre-T2 macs just to make sure the normal IO port path works ok?

sys/dev/asmc/asmc.c
461–463	Hm, ideally we'd be able to do this without this check. all the other drivers manage it! let me see what's causing trouble.
sys/dev/asmc/asmcvar.h
60	I'd put a space after here eventually to demarcate what's t2 / mmio. (nowdays I use anonymous structs inside the softc to group things.)

adrian accepted this revision.Sat, May 30, 1:27 AM

This revision is now accepted and ready to land.Sat, May 30, 1:27 AM

I'll be AFK this weekend, so I don't want to block merging this change. It would be good to address these issues before merge though to avoid having to do it after the fact.

sys/dev/asmc/asmcmmio.c
46	style(9) (there might be other instances that need to be handled elsewhere...)
70	I'm not sure if this is the right value to test with. Maybe @imp or @jhb has some thoughts here?
86–112	`mtx_unlock_spin(..)` is being called multiple times in multiple exit paths. I think this should use a goto.
147–156
181	Similar comment as before in this function...
212	Similar comment as before in this function.
256	Similar comment as before in this function.
sys/modules/asmc/Makefile
4	Why not `asmc_mmio.c`?