On Tue, 2008-05-27 at 15:42 -0600, Matthew Wilcox wrote: > On Wed, May 28, 2008 at 07:38:55AM +1000, Benjamin Herrenschmidt wrote: > > A problem with __raw_ though is that they -also- don't do byteswap, > > which is a pain in the neck as people use them for either one reason > > (relaxed ordering) or the other (no byteswap) without always knowing the > > consequences of doing so... > > That's why there's __readl() which does byteswap, but doesn't do > ordering ... Ah, that one is news to me. I don't think we ever had it on powerpc :-) > > I'm happy to say that __raw is purely about ordering and make them > > byteswap on powerpc tho (ie, make them little endian like the non-raw > > counterpart). > > That would break a lot of drivers. How many actually use __raw_ * ? > > Some archs started providing writel_be etc... I added those to powerpc a > > little while ago, and I tend to prefer that approach for the byteswap > > issue. > Those are for people who use big endian chips on little endian > architectures. Why limit them to LE architecture ? There is nothing fundamentally speicifc to LE architectures here, and it's wrong to provide accessors on some archs and not others. The endianness is a property of the device registers. Current writel/readl are basically writel_le/readl_le. It thus makes sense to have the opposite, ie, readl_be/writel_be, which thus byteswaps on LE platforms and not on BE platforms, which is what I provided on powerpc a while ago. Ben. -- 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
