On Thursday 14 May 2015 18:49:17 Timur Tabi wrote: > Guenter Roeck wrote: > > > > We still don't know if the registers are in host byte order or in little > > endian > > order. If registers are in host byte order, there is no need for a > > conversion. > > Well, if I compile and boot a big-endian ARM64 kernel, then I don't > expect the hardware devices to magically switch all their registers into > big endian. The devices will remain little-endian. > > I presume that this is true on all ARM and ARM64 systems. Switching the > CPU into big-endian mode (when it normally would run in little-endian) > does not also switch the hardware registers. > > Therefore, if we want to support big-endian kernels on ARM64, then every > readl/writel in every driver must use cpu_to_le32/etc. > > I think this conversation has gone off-track. I don't see how the SBSA > watchdog device is any different from any other device on an ARM64 platform. > > I think it's safe to say that the endian order is not specified > anywhere, but on my hardware, everything is little-endian. Then please remove the double-swap. If the device works like any other device in the system, then the byteswap that is implied by readl/writel will do the right thing, and swapping twice will break big-endian kernels. Arnd -- To unsubscribe from this list: send the line "unsubscribe linux-watchdog" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
