[U-Boot] WARNING: in gcc 4.5.0 and 4.5.1 volatile is ignored

[Alexander Holler <holler@ahsoftware.de>]

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