Hello,
because I've recently seen some other places where volatile is used to access registers without using read?() or write?() and many people seem to start using 4.5.1, I want to post this warning using a descriptive subject.
The keyword volatile might not have any effect when reading when gcc 4.5.0 or 4.5.1 is used.
The appropriate bug seems to be that one:
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45052
You might either change such code to use readb(), readw() or readl(), or you have to use either an older version of gcc or a version >= 4.5.2 (it is fixed in 4.5.2).
A patch for write?() and read?() is currently in the u-boot-arm-repository (but not in the master and not in 2010.12):
http://lists.denx.de/pipermail/u-boot/2011-January/084885.html
Regards,
Alexander