Messages in this thread | | | From | Arnd Bergmann <> | Subject | Re: [PATCH v6 6/6] pci: Add support for creating a generic host_bridge from device tree | Date | Mon, 10 Mar 2014 16:21:01 +0100 |
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On Monday 10 March 2014 14:44:14 Liviu Dudau wrote: > I will try to improve the error handling in the next patchset version. > However I am still confused about the earlier discussion on > pci_register_io_range(). Your suggestion initially was to return an > error in the default weak implementation, but in your last email you > are talking about returning 'port'.
You can do either one: 'port' should be positive or zero, while the error would always be negative. We do the same thing in many interfaces in the kernel.
> My idea when I've introduced the > helper function was that it would return an error if it fails to > register the IO range and zero otherwise. I agree that we can treat > the default 'do nothing with the IO range' case as an error, with > the caveat that will force architectures that use this code to > provide their own implementation of pci_register_io_range() in order > to avoid failure, even for the cases where the architecture has a 1:1 > mapping between IO and CPU addresses.
Which architectures are you thinking of? The only one I know that does this is ia64, and we won't ever have to support this helper on that architecture.
I did not ask to treat 'do nothing with the IO range' as an error, what I meant is that we should treat 'architecture cannot translate from I/O space to memory space but DT lists a translation anyway' as an error. On x86, you should never see an entry for the I/O space in "ranges", so we will not call this function unless there is a bug in DT.
Arnd
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