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. >> > For our case, the ".config" file does not define 'CONFIG_HAS_IOMEM', can >> > I assume it means "CONFIG_HAS_IOMEM=n" ? > If I'm not mistaken it works the other way around. > All archs except UML and s390 set CONFIG_HAS_IOMEM=y. I guess so, too. Thanks. -- Chen Gang Asianux Corporation -- 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
