On Sat, Aug 29, 2015 at 08:25:05AM -0700, Christoph Hellwig wrote: > On Fri, Aug 28, 2015 at 05:17:27PM -0700, Luis R. Rodriguez wrote: > > From: "Luis R. Rodriguez" <mcgrof@xxxxxxxx> > > > > The S390 architecture requires a custom pci_iomap() implementation > > as the asm-generic implementation assumes there are disjunctions > > between PCI BARs, and on S390 PCI BAR are not disjunctive, S390 requires > > the bar parameter in order to find the corresponding device and create > > the mapping cookie. > > > > This clash with the asm-generic pci_iomap() implementation is implicit, > > there are no current semantics to make this incompatability explicit. > > Make the S390 PCI BAR non-disjunction incompatibility explicit, and > > also pave the way for alternative incompatibilities to be defined. > > > > While at it, as with the ioremap*() variants, since we have no clear > > semantics yet well defined provide a solution for them that returns > > NULL. This allows architectures to move forward by defining pci_ioremap*() > > variants without requiring immediate changes to all architectures. Each > > architecture then can implement their own solution as needed and > > when they get to it. > > Now that you have the config symbol available why not move the S390 > implementation to generic code based on that can kill of > asm/pci_iomap.h? Seems like we're really not dealing with something > inherent to the architecture, but two possible implementations based > on architecture constraints. That would be the other approach to take too, but perhaps that can wait until yet another architecture with similar requirement pops up. Luis -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
