[PATCH V3 3/4] ARM: Xilinx: base header files and assembly macros

[Russell King - ARM Linux]

On Thu, Feb 17, 2011 at 03:41:11PM +0100, Arnd Bergmann wrote:
> On Thursday 17 February 2011, John Linn wrote:
> > > > +
> > > > +#define UART_FIFO_WRITE(base, value) \
> > > > +   (*(volatile unsigned int *)((base) + UART_FIFO_OFFSET) =
> > (value))
> > > > +
> > > > +#define UART_STATUS(base) \
> > > > +   (*(volatile unsigned int *)((base) + UART_SR_OFFSET))
> > > 
> > > You could probably make these static inline functions in the header
> > and
> > > use __raw_{readl,writel}() to make this a little cleaner.
> > > 
> > 
> > I had considered that, but it wasn't clear to me at the time what the
> > compressor could use or not.
> > 
> > I'll give it a try as I agree that's cleaner.
> 
> Actually, for correctness you should use the regular readl/writel, not
> the __raw_ versions, which can result in reordered or partial accesses
> on the bus.

Not in the decompressor.  readl/writel are unsupported there - the
decompressor doesn't have the L2 cache support code and so the barriers
necessary for readl/writel cause link errors.