> --- linux-2.6.24-rc4.orig/include/asm-x86/io_64.h 2007-12-11 > 14:24:56.000000000 -0800 > +++ linux-2.6.24-rc4/include/asm-x86/io_64.h 2007-12-11 15:49:52.000000000 > -0800 > @@ -142,7 +142,8 @@ > * it's useful if some control registers are in such an area and write > combining > * or read caching is not desirable: > */ > -extern void __iomem * ioremap_nocache (unsigned long offset, unsigned long > size); > +extern void __iomem * ioremap_nocache(unsigned long offset, unsigned long > size); > +extern void __iomem * ioremap_wc(unsigned long offset, unsigned long size);
I think ioremap_wc() needs to be available on all archs for this to be really useful to drivers. It can be a fallback to ioremap_nocache() everywhere except 64-bit x86, but it's not nice for every driver that wants to use this to need an "#ifdef X86" or whatever. Also I didn't see anything like pgprot_wc() in the patchset (although I just skimmed quickly for now). The use case I actually have would be in a a driver's .mmap method, where I want to map device registers into userspace with write-combining turned on: vma->vm_page_prot = pgprot_wc(vma->vm_page_prot); io_remap_pfn_range(vma, vma->vm_start, pfn, PAGE_SIZE, vma->vm_page_prot); where the pfn points into a PCI BAR (which will only be mapped once, so no issues with conflicting PATs or anything like that). - R. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/