On 07/18/2014 05:05 AM, Arnd Bergmann wrote: > On Thursday 17 July 2014 16:41:14 Chris Metcalf wrote: >> On 7/17/2014 7:28 AM, Chen Gang wrote: >>> On 07/17/2014 06:48 PM, Arnd Bergmann wrote: >>>> AFAICT, NO_IOMEM only has a real purpose on UML these days. Could we take >>>> a shortcut here and make COMPILE_TEST depend on !UML? Getting random stuff >>>> to build on UML seems pointless to me and we special-case it in a number of >>>> places already. >>>> >>> According to current source code, tile still has chance to choose >>> NO_IOMEM, for me, welcome the tile's maintainer's ideas or suggestions. >> >> I'm not really sure. It's true that on tile, if you don't enable PCI >> support there's no other I/O memory (or I/O port) space you can use. >> We pretty much always enable PCI support in our kernel, though. I'm >> kind of surprised that other architectures don't also have the model >> that IOMEM requires PCI, but perhaps most architectures just don't >> encode that in the Kconfig file? > > Only s390 as far as I know. Most architectures have integrated > peripherals that use MMIO without PCI. > >> My observation is just that if I remove the "NO_IOMEM if !PCI" from >> arch/tile/Kconfig, my build fails with ioremap() undefined. No doubt I >> could work around that, but my assumption was that NO_IOMEM was exactly the >> right thing to express the fact that without PCI there is no I/O memory > > Your assumption is correct. > > For tile by itself it would certainly be best to leave this > dependency, it makes no sense to enable IOMEM without PCI. > > That doesn't solve the problem of COMPILE_TEST enabling drivers > that require IOMEM though. An easy hack for that would be to > make COMPILE_TEST depend on HAS_IOMEM, but it gets into hacky territory > there, and it's not clear if this is any better than the original patch > to provide fallbacks for ioremap and friends. Definitely simpler > though. > OK, thank all of you, tile just likes most of architectures to support IOMEM, and at present, we can focus score and uml only. Thanks. -- Chen Gang Open, share, and attitude like air, water, and life which God blessed _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
