Messages in this thread | | | From | Kumar Gala <> | Subject | Re: [PATCH 6/13] devres: implement managed iomap interface | Date | Thu, 10 Apr 2008 12:44:12 -0500 |
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On Apr 10, 2008, at 11:56 AM, Sergei Shtylyov wrote: > 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...
but there is no reason not to make it work properly. For example I believe libata uses devm_* and the fsl SATA driver (non-PCI) will need to work in cases similar to the 44x.
- k
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