Russell, On Tue, 11 Dec 2012 16:23:25 +0000, Russell King - ARM Linux wrote:
> > * ARCH_VEXPRESS should not select NO_IOPORT. It's generally wrong > > to select this in combination with ARCH_MULTIPLATFORM, when some > > of the other platforms you may enable actually have IOPORT mapping > > support. > > No. ARCH_VEXPRESS selects NO_IOPORT because it _does_ _not_ support > PCI/ISA IO space. That in itself is reasonable, but what isn't > reasonable is the _negative_ logic being used. Negative logic in > the config system always tends to provoke this kind of sillyness > because you're selecting something to be excluded which another > platform may require. Could you enlighten my very naive understanding of things about PCI/ISA IO space? On x86, I seem to understand this is the separate address space accessed by the special in/out CPU instructions. Are there ARM platforms with the same sort of things? As far as I understand, on my ARM Marvell system, everything is memory-mapped, so there isn't such a separate PCI/ISA IO space. Therefore, why would I need to "select HAVE_IOPORT" simply to be able to build libata-sff.c, that is used for PCI drivers that work fine with purely memory-mapped registers? Sorry for the stupid/naive questions, but it'll definitely help to understand the matter. Thanks, Thomas -- Thomas Petazzoni, Free Electrons Kernel, drivers, real-time and embedded Linux development, consulting, training and support. http://free-electrons.com -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
