On Thu, Apr 06, 2017 at 01:11:57PM +0100, Russell King - ARM Linux wrote: > On Thu, Apr 06, 2017 at 12:53:12PM +0200, Luis R. Rodriguez wrote: > > On Thu, Apr 06, 2017 at 11:26:36AM +0100, Lorenzo Pieralisi wrote: > > > Indeed, the static inline ioremap_nocache() fallback does not work > > > on all arches (whether I add the fallback in linux/io.h or > > > asm-generic/io.h is irrelevant), I bump into issues such as the one > > > reported above. > > > > Its also not *safe* to assume on behalf of all architectures a new ioremap > > call is both a good idea and proper. > > You may be right in general, but not in this case. > > Currently, many drivers use plain ioremap() to map this resource. We > are replacing that existing call - which is known to work in the majority > of cases - with a new call to cater for different semantics required by > an architecture. > > Doing a replace of these ioremap() calls with ioremap_nopost() in this > situation, and then having ioremap_nopost() fail is a recipe for causing > lots and lots of regressions. > > The only sane approach is to have ioremap_post() default to modelling the > _existing_ behaviour everywhere that it is used. > > Requiring it to fail until architecture folk trip over the failure is > totally insane, and I very strongly disagree with you on this. Ah yes, what if with this modulo rule of thumb: The litmus test then is if an existing set of calls are changed to use a new ioremap then all archs that support those drivers where the new call is being added must be modified to also have a correct corresponding API call ? This is more work on the new person introducing the new API, and should require review still on arch maintainers but it seems like a fair compromise. Then if an API is *new* though then things can move forward without requiring all archs to add the respective call. Luis
