[PATCH 2/2] ARM: cci: driver need big endian fixes in asm code

[Nicolas Pitre]

On Tue, 8 Oct 2013, Dave Martin wrote:

> On Mon, Oct 07, 2013 at 09:37:20PM -0700, Victor Kamensky wrote:
> > cci_enable_port_for_self written in asm and it works with h/w
> > registers that are in little endian format. When run in big
> > endian mode it needs byte swap before/after it writes/reads
> > to/from such registers
> 
> Lorenzo should comment on this if he's not already seen it.
> 
> > 
> > Signed-off-by: Victor Kamensky <victor.kamensky at linaro.org>
> > ---
> >  drivers/bus/arm-cci.c | 6 ++++++
> >  1 file changed, 6 insertions(+)
> > 
> > diff --git a/drivers/bus/arm-cci.c b/drivers/bus/arm-cci.c
> > index 2009266..6db173e 100644
> > --- a/drivers/bus/arm-cci.c
> > +++ b/drivers/bus/arm-cci.c
> > @@ -281,6 +281,9 @@ asmlinkage void __naked cci_enable_port_for_self(void)
> >  	/* Enable the CCI port */
> >  "	ldr	r0, [r0, %[offsetof_port_phys]] \n"
> >  "	mov	r3, #"__stringify(CCI_ENABLE_REQ)" \n"
> > +#ifdef __ARMEB__
> > +"	rev	r3, r3 \n"
> > +#endif /* __ARMEB__ */
> 
> Hmmm, this is a bit ugly, but we can't easily use ARM_BE8() here.

In any case, it would be more efficient to swap the CCI_ENABLE_REQ 
constant at compile time rather than doing it at run time with an extra 
instruction.


Nicolas