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RFC arm: pcibios: remove pci_sys_data domain

Jason Gunthorpe linux-arm-kernel linux-pci 1 version New

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  1. v1 RFC Latest0 of 2 patches 0 repliesNew

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Cover letter [RFC PATCH 0/2] arm: pcibios: remove pci_sys_data domain
Quoted 21 lines · Lorenzo Pieralisi
Quoted 7 lines · Jason Gunthorpe
Quoted 4 lines · Lorenzo Pieralisi

Code in drivers/pci/pci-mvebu.c has been changed to add a domain number to PCI resources by using the nr value coming from the setup pcibios32 callback, which may not be correct and should be considered a temporary solution waiting for review comments.

Quoted 7 lines

The intent of the string was to have the domain number so that resources in /proc/iomem can be correlated with lspci.

This would be a 'best practice' - all PCI drivers need to request resource, and the resource should be relatable back to the PCI domain... So it would be best if the domain number was available at this point in a driver's flow.

It is not available with the new approach and the generic PCI domains since the set-up hook is called before creating the pci_bus. That's why I mentioned that in the cover letter, and that's good it caught your attention.

Quoted 6 lines

On a side note, when the resources are parsed from DT ranges, ie in:

of_pci_get_host_bridge_resources()

the resources won't contain the domain number you are looking for here, for the records, so we'd better find an agreement sooner rather than later.

Well, it is very unfortunate that things are globally not sequenced to allow proper resource names :(

But it also isn't really a big deal in the grand scheme of things. Maybe it can be fixed later :|

Quoted 3 lines

So basically I could go as far as sticking 0000 to the string given the current code. I did not drop the 0x04x entirely since I do not want to break userspace, I was tempted though, let me know if I am allowed to do that.

I'd just drop it entirely then, nobody is going to parse /proc/iomem

Jason