[RFC 1/6] atmel: add atmel_io.h

[Russell King - ARM Linux]

On Sat, Mar 28, 2015 at 07:20:48PM +0100, Alexandre Belloni wrote:
> Hi,
> 
> On 26/03/2015 at 12:51:23 +0100, Hans-Christian Egtvedt wrote :
> > Around Thu 26 Mar 2015 11:45:49 +0000 or thereabout, Ben Dooks wrote:
> > > The AVR32 and ARM (AT91) architectures share a number of drivers which
> > > need to access the on chip peripherals. The current drivers work with
> > > the default endian configuration, however it is possilbe to run some of
> > > the ATMEL ARM architectures in big endian mode.
> > > 
> > > If we change the drivers from __raw to _relaxed IO accesors then the ARM
> > > side works but the AVR32 will not. The _relaxed assume the bus is little
> > > endian and the __raw are native. The AVR32 is native big endian so these
> > > are not the right functions.
> > > 
> > > To sort this out, and avoid a number of drivers having #ifdef for the
> > > AVR32 case we add <linux/atmel_io.h> to provide some AT91/AVR32 independant
> > > IO accessor functions.
> > > 
> > > Signed-off-by: Ben Dooks <ben.dooks at codethink.co.uk>
> > 
> > Acked-by: Hans-Christian Egtvedt <egtvedt at samfundet.no>
> > 
> 
> Is there any reason why read/write[bwl]_relaxed can't be made to do big
> endian accesses on avr32?

read/write[bwl]* are defined to be little endian accessors - they have
their roots in PCI.

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