[PATCH v5 2/6] arch: unify ioremap prototypes and macro aliases

On Wed, Jul 01, 2015 at 08:55:57AM +0200, Geert Uytterhoeven wrote:

quoted

I think doing this at runtime might be a better idea.  E.g. a
ioremap_flags with the CACHED argument will return -EOPNOTSUP unless
actually implemented.  On various architectures different CPUs or
boards will have different capabilities in this area.

So it would be the responsibility of the caller to fall back from
ioremap(..., CACHED) to ioremap(..., UNCACHED)?
I.e. all drivers using it should be changed...

All of the zero users we currently have will need to be changed, yes.

Note that I propose to leave ioremap(), aka ioremap_flags(..., 0) as
a default that always has to work, -EOPNOTSUP is only a valid return
value for non-default flaga.