Am 26.06.2013 10:58, schrieb Chen Gang: > On 06/26/2013 04:39 PM, Richard Weinberger wrote: >>>>>>>>>> The drivers internal code has already check the related return value, >>>>>>>>>> so it is the architecture's duty to 'tell' the driver whether support >>>>>>>>>> io memory (e.g. define ioremap, but return NULL). >>>>>> It does so already by setting CONFIG_HAS_IOMEM=n >>>> >>>> Excuse me, I use "grep -rn ioremap *" under "include/" and "arch/um/" >>>> directory, but can not find the related definition for 'ioremap'. >>>> >>>> Is there another declaration or definition way which I don't know ? >>>> (maybe it is). >> Both UML and s390 (in the !CONFIG_PCI) do not define ioremap() because >> without io memory you cannot have a ioremap(). >> > > I assume if ioremap() return NULL, it means "without io memory", is it > correct ? > > If it is correct, "define a dummy ioremap(), and return NULL" is just > the meaning that you mentioned above. > > If so, for UML, it is not requirement, but recommend to define a dummy > ioremap() which return NULL, so can be generic enough to mach all cases. No. Not setting CONFIG_HAS_IOMEM=y means "This arch has no io memory and therefore no functions to mess with it". Let's get back to the real problem, drivers/ptp/ptp_pch.c does not build on UML (and I'm very sure also not on S390). Fix the issue by making it depend on HAS_IOMEM. Btw: Did you actually look at this driver? There is *zero* reason to have it on UML. ...like 99.9% of all other drivers which use io memory. Thanks, //richard -- 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
