Is volatile always verboten for FSL QE structures?
Kumar Gala
galak at kernel.crashing.org
Sat Oct 3 02:41:28 EST 2009
On Oct 2, 2009, at 9:46 AM, Timur Tabi wrote:
> Michael Barkowski wrote:
>> Just wondering - is there a case where using volatile for UCC
>> parameter RAM for example will not work, or is the use of I/O
>> accessors everywhere an attempt to be portable to other
>> architectures?
>
> 'volatile' just doesn't really do what you think it should do. The
> PowerPC architecture is too complicated w.r.t. ordering of reads and
> writes. In other words, you can't trust it.
>
> No one should be using 'volatile' to access I/O registers.
See Documentation/volatile-considered-harmful.txt
- k
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