[U-Boot] [PATCH v2 2/9] sunxi: initial sun7i pinmux and gpio support

Ian Campbell
2014-03-27T21:52:35Z

On Wed, 2014-03-26 at 10:01 +0100, Wolfgang Denk wrote:
> I'm not an expert for ARM, but this indeed looks suspiscious - thanks
> for reporting this.

FYI I made the change which prompted this and the resulting code was the
same see https://groups.google.com/forum/#!topic/linux-sunxi/REZ18q0wcDY
The barriers were only ever compile barrier() type, not cpu barriers.

So the open coded thing was effectively:
v = read();
barrier();
v = fiddlebits(b)
barrier();
write(v);

Whereas the code using clrsetbits is basically:
write(fiddlebits(read()))

Which I think is OK in this case at least. Not sure about the general
case.

Ian.