Hi Ard, > -----Original Message----- > From: Ard Biesheuvel [mailto:[email protected]] > Sent: Monday, October 17, 2016 1:12 PM > To: Kinney, Michael D <[email protected]> > Cc: Gao, Liming <[email protected]>; Bhupesh Sharma > <[email protected]>; [email protected] > Subject: Re: [edk2] [PATCH 1/1] MdePkg/IoLib: Add support for big- > endian MMIO > > On 17 October 2016 at 05:10, Kinney, Michael D > <[email protected]> wrote: > > Bhupesh, > > > > It is also possible to add an ARM specific PCD to select endianness > > and update MdePkg/Library/BaseIoLibIntrinsic/IoLibArm.c to use that > > PCD in MmioRead/Write() APIs in that file to support both endian > > types. You can use the SwapBytesxx() functions from BaseLib(as > Laszlo > > suggested) based on the setting of this ARM specific PCD. > > > > Modules that link against this lib can select endianness by setting > > PCD in the scope of that module. > > > > The IPF version of IoLib uses an IPF specific PCD to translate I/O > > port accesses to MMIO accesses. So there is already an example of an > > arch specific PCD in this lib instance. > > > > This is not a platform wide thing, it is a per-device property whether > the MMIO occurs in big endian or little endian manner. > > So I think Liming's suggestion makes sense: create an IoLib > implementation that performs the byte swapping, and selectively > incorporate it into drivers that require it using > > BeMmioDeviceDxe.inf { > <LibraryClasses> > IoLib|SomePkg/Library/BigEndianIoLib.inf > }
That's correct. I think creating a separate IoLib for byte-swapping makes sense. We will rework the patch accordingly. Regards, Bhupesh _______________________________________________ edk2-devel mailing list [email protected] https://lists.01.org/mailman/listinfo/edk2-devel
