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SubjectRe: [PATCH 6/13] devres: implement managed iomap interface
Hello, I wrote:

>>> Those functions are going to break on 32-bit platforms with
>>> extended physical address (well, that's starting with Pentiums which
>>> had 36-bit PAE :-) AND devices mapped beyond 4 GB (e.g. PowerPC
>>> 44x). You should have used resource_size_t for the 'offset'
>>> parameter. As this most probably means that libata is broken on such
>>> platforms, I'm going to submit a patch...

> It's broken with drivers using MMIO, I meant to say.

Oops, I meant PCI drivers here, at least for the time being. And it looks
like that was a false alarm. :-]

>> Yeah, right please go ahead. But I wonder whether any BIOS was
>> actually crazy enough to map mmio region above 4G on 32bit machine.

> This is a *hardware* mapping on some non-x86 platforms (like PPC 44x
> or MIPS Alchemy). The arch/ppc/ and arch/mips/ kernels have special
> hooks called from ioremap() which help create an illusion that the PCI
> memory space on such platforms (not only it) is mapped below 4 GB;
> arch/powerpc/ kernel doesn't do this anymore -- hence this newly
> encountered issue.

I thought that pcim_iomap() used devm_ioremap() or something -- which of
course turned to be wrong. devm_ioremap() alone is yet safe since there are no
users for it amongst PPC 44x platform device drivers...

MBR, Sergei

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