Re: Should io(read|write)(8|16|32)_rep take (const|) volatile u(8|16|32) __iomem *addr?

Jeff Garzik
2007-02-02T21:40:15Z

Michael K. Edwards wrote:
> Doubtless this is on purpose, but it's not clear to me why that should
> be true for these particular functions/macros. I shouldn't have to
> cast away the volatile on a pointer to hardware registers in order to
> pass it into writel(), should I? And it shouldn't be forbidden for
> the caller to declare the pointer volatile so that the compiler
> catches attempts to pass it into non-volatile interfaces, should it?

Therein lies your bug: you should not be annotating your __iomem
pointers with volatile.

That's why volatile is found in the implementation and not the
prototypes of the accessor functions.

Jeff