[U-Boot] [PATCH 1/3] Create API to map between CPU physical and bus addresses

Marek Vasut
2015-03-25T14:57:01Z

On Wednesday, March 25, 2015 at 03:40:28 PM, Stephen Warren wrote:
> On 03/25/2015 05:55 AM, Marek Vasut wrote:
> > On Wednesday, March 25, 2015 at 03:07:33 AM, Stephen Warren wrote:
> >> On some SoCs, DMA-capable peripherals see a different address space to
> >> the CPU's physical address space. Create an API to allow
> >> platform-agnostic drivers to convert between the two address spaces
> >> when programming DMA operations.
> >>
> >> This API will exist on all platforms, but will have a dummy
> >> implementation when this feature is not required. Other platforms will
> >> enable
> >> CONFIG_PHYS_TO_BUS and provide the required implementation.
> >>
> >> Signed-off-by: Stephen Warren <swarren@wwwdotorg.org>
> >
> > Applied to -next, thanks!
> >
> > btw. can't you use __weak here instead of a new ifdef macro (which is not
> > documented btw)?
>
> __weak wont' work with inlines, which I used to ensure zero code
> overhead in the case the functions aren't needed. If we were OK with
> calling a no-op function in all cases, we could indeed provide a weak
> default implementation and get rid of the ifdef.

OK, makes sense.

> The new option is documented in the Kconfig file. I assume we don't need
> to document options in multiple places (both Kconfig and README), since
> if we do, the documentation is bound to become inconsistent in those two
> places. Hopefully README goes away once everything is in Kconfig.

Yup, agreed.

Thanks for clearing this up :)

Best regards,
Marek Vasut