Hi guys, What's the correct way to read from PCI address space (basically it's guaranteed to be non-coherent memory bar) without flipping bits like ioread32() does?
I need to be able to copy a bank of registers from PCI address space into a temporary buffer so I can compare them in userspace through UIO. Because of the flipping and the difference between the original kernel driver (which used ioread32() and therefore "saw" big endian) and the userspace app (which has a direct view of the PCI space, and therefore "sees" little endian) I decided to give userspace an absolutely consistent little-endian view seeing as this may get ported to ARM in the coming months. I want to put as little code in there as possible and not laboriously manually flip from my ioread32() big endian values to little endian again (waste of time and code) if I can help it. Being able to read the raw value would help a lot, and if I need to do calculations on a small portion of the data then I can do the flips manually then (using le32_to_cpu and cpu_to_le32 which will be a noop on ARM), reducing the amount of porting I need to do in both kernel and userspace alike. So, is there something like a direct ioread32le() or so, which will not change behaviour across architectures, is present on ARM and PPC, and will handle both PCI address space, and "normal" "ioremapped" memory? -- Matt Sealey <m...@genesi-usa.com> Genesi, Manager, Developer Relations _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev