Messages in this thread | | | Date | Tue, 11 Dec 2012 17:38:19 +0100 | From | Thomas Petazzoni <> | Subject | Re: [RFC v1 01/16] lib: devres: don't enclose pcim_*() functions in CONFIG_HAS_IOPORT |
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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
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