Add a way to map arm64 non-posted device memory
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Authored by andrew on Apr 12 2021, 9:33 AM.

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Reviewers

manu
imp

Group Reviewers

arm64
manpages

Commits

rG2abd4f858146: Add a way to map arm64 non-posted device memory

Summary

On arm64 we currently use a non-posted write for device memory, however
we should move to use posted writes. This is expected to work on most
hardware, however we will need to support a non-posted option for some
broken hardware.

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Repository

rG FreeBSD src repository

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Event Timeline

andrew created this revision.Apr 12 2021, 9:33 AM

Herald added a reviewer: manu. · View Herald TranscriptApr 12 2021, 9:33 AM

Herald added a reviewer: manpages. · View Herald Transcript

Herald added subscribers: emaste, imp. · View Herald Transcript

andrew requested review of this revision.Apr 12 2021, 9:33 AM

Harbormaster completed remote builds in B38525: Diff 87301.Apr 12 2021, 9:34 AM

Pass ma to pmap_mapdev_attr

Harbormaster completed remote builds in B38526: Diff 87302.Apr 12 2021, 9:35 AM

OK from manpages.

manu added inline comments.Apr 12 2021, 11:34 AM

sys/arm64/include/vm.h
44	They are both the same, is that a typo ?

andrew added inline comments.Apr 12 2021, 11:43 AM

sys/arm64/include/vm.h
44	I'm planning on changing `VM_MEMATTR_DEVICE` to `VM_MEMATTR_DEVICE_nGnRE`, but need to update the PCIe drivers to use non-posted memory for their config space first.

manu accepted this revision.Apr 12 2021, 11:51 AM

manu added inline comments.

sys/arm64/include/vm.h
44	Ok thanks, maybe include that in the commit message so people don't ask the same question as me :)

This revision is now accepted and ready to land.Apr 12 2021, 11:51 AM

Teach vmstat about VM_MEMATTR_DEVICE_NP
Add a comment explaining why the device meory types are the same

This revision now requires review to proceed.Apr 12 2021, 1:43 PM

Harbormaster completed remote builds in B38530: Diff 87309.Apr 12 2021, 1:43 PM

imp accepted this revision.Apr 12 2021, 3:01 PM

This revision is now accepted and ready to land.Apr 12 2021, 3:01 PM

We'll never have 'old broken devices' needing to use the BUS_SPACE_MAP_NONPOSTED attribute any place except arm64 because that's the only place they could possibly be, right?
Do we have any notion of which devices might be like this? Or is this a easy to do patch that allows quick 'CYA' fixes later if one remains hidden?

manu accepted this revision.Apr 12 2021, 4:04 PM

It's needed by the Tegra PCIe driver as it maps its config space via bus_space_map. The other PCI drivers use bus_alloc_resource_any for their config space so can be updated to use RF_UNMAPPED and bus_map_resource.