On Fri, Feb 20, 2009 at 02:05:08PM -0600, Matt Sealey wrote: > On Fri, Feb 20, 2009 at 1:11 PM, Ira Snyder <i...@ovro.caltech.edu> wrote: > > On Fri, Feb 20, 2009 at 12:57:36PM -0600, Matt Sealey wrote: > > > > I'm pretty sure memcpy_fromio() and memcpy_toio() will get you what you > > want. They don't change byte ordering. > > Are they guaranteed to only do 32-bit, aligned accesses? >
I don't think so. I certainly wouldn't count on anything better than a byte-by-byte memcpy. > I made some cheats on my CPLD to ignore byte enables and so on, > because it makes the design cleaner and easier to read (for students) > plus, saves a ton of logic cells. It's totally within the PCI > standard, but it means if you do a byte read memcpy() you get.. very > weird results (i.e. not great). > Right, I understand how that works :) Some usage of cscope shows that __raw_readl() might be what you want, as well as __raw_writel() for writing. I'm not sure it is universally available, but maybe they are. The comment on PowerPC says "Non ordered and non-swapping "raw" accessors". Looks about right. ARM's implementation uses them to implement ioread32() and friends by adding byteswapping. Hope it helps, Ira > -- > 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
