[U-Boot] [PATCH v3 03/13] fdtdec: Add fdt_{addr, size}_unpack() helpers

[Simon Glass]

Hi Thierry,

On Fri, 22 Mar 2019 at 02:31, Thierry Reding <thierry.reding at gmail.com> wrote:
>
> On Fri, Mar 22, 2019 at 03:53:00PM +0800, Simon Glass wrote:
> > Hi Thierry,
> >
> > On Fri, 22 Mar 2019 at 02:10, Thierry Reding <thierry.reding at gmail.com> wrote:
> > >
> > > From: Thierry Reding <treding at nvidia.com>
> > >
> > > These helpers can be used to unpack variables of type fdt_addr_t and
> > > fdt_size_t into a pair of 32-bit variables. This is useful in cases
> > > where such variables need to be written to properties (such as "reg")
> > > of a device tree node where they need to be split into cells.
> > >
> > > Signed-off-by: Thierry Reding <treding at nvidia.com>
> > > ---
> > > Changes in v2:
> > > - new patch
> > >
> > >  include/fdtdec.h | 25 +++++++++++++++++++++++++
> > >  1 file changed, 25 insertions(+)
> > >
> > > diff --git a/include/fdtdec.h b/include/fdtdec.h
> > > index a965c33157c9..a0ba57c6318b 100644
> > > --- a/include/fdtdec.h
> > > +++ b/include/fdtdec.h
> > > @@ -23,6 +23,31 @@
> > >   */
> > >  typedef phys_addr_t fdt_addr_t;
> > >  typedef phys_size_t fdt_size_t;
> > > +
> > > +static inline fdt32_t fdt_addr_unpack(fdt_addr_t addr, fdt32_t *upper)
> > > +{
> > > +       if (upper)
> > > +#ifdef CONFIG_PHYS_64BIT
> >
> > Could we use 'if IS_ENABLED()' instead?
>
> Are you suggesting to use IS_ENABLED() in a preprocessor #if or a
> compiler if (IS_ENABLED(...)) { ... } construct? For the former, yes we
> could certainly do that.
>
> The latter would probably work as well if we did something like this:
>
> > > +               *upper = addr >> 32;
>
>                 *upper = upper_32_bits(addr);
>
> where upper_32_bits() is a macro such as the one defined in Linux'
> include/linux/kernel.h. That prevents the right-shift of 32 bits for
> 32-bit quantities to not produce a warning.
>
> That said, I see that we already have that macro in U-Boot's kernel.h
> header file, so I could switch to using that. With that I think we could
> even leave out the conditional. The compiler would hopefully optimize it
> (the upper_32_bits() invocation) out by itself.
>
> I'll do some testing and respin if that works out.

Applied to u-boot-dm, thanks!

Please do a fixup patch if this works out. I hope I didn't miss an email/patch.

Regards,
Simon