GSoC 2020: Implementation of OFW functions

[Sebastian Huber]

On 07/05/2020 12:28, Niteesh G. S. wrote:

> On Thu, May 7, 2020 at 1:21 PM Sebastian Huber 
> <sebastian.huber at embedded-brains.de 
> <mailto:sebastian.huber at embedded-brains.de>> wrote:
>
>     On 07/05/2020 09:35, Niteesh G. S. wrote:
>
>     > This is what I was trying to convey in one of the previous mails.
>     > https://lists.rtems.org/pipermail/devel/2020-May/059717.html
>     > But in that mail, I was planning to replace KOBJLOOKUP.
>     > Should I start working on it? From the top of my mind, the
>     following has
>     > to be done.
>     > 1) Import openfirm.c openfirm.h, ofw_fdt.c
>     > 2) Add ofw_fdt.h since all the functions in ofw_fdt are static.
>     > Should we also import ofw_if.h? Because that is where OFW_*
>     functions
>     > are defined or just add a ofw_rtems_map.h which redefines them,
>     instead
>     > of importing ofw_if.h?
>
>     The KOBJ stuff in the OFW support enables FreeBSD to have three
>     different implementations of the OFW API which can be selected at
>     runtime:
>
>     sys/powerpc/ofw/ofw_real.c
>     sys/dev/ofw/ofw_standard.c
>     sys/dev/ofw/ofw_fdt.c
>
>     In libbsd this is already short cut to the FDT implementation:
>
>     #ifndef __rtems__
>     static ofw_def_t    *ofw_def_impl = NULL;
>     #else /* __rtems__ */
>     #define    ofw_def_impl (&ofw_fdt)
>     #endif /* __rtems__ */
>
>     To me this looks like the KOBJ stuff was just used to enable some
>     sort
>     of object oriented programming. Do we need this flexibility at
>     runtime
>     in RTEMS? I would say no. I would hard wire this to the FDT
>     implementation. If someone has a problem with it in the future, this
>     decision can be readdressed.
>
>
> Ok. But what is the neatest way to hardwire this to the FDT 
> implementation?
> One way as Christian mentioned would be to redefine OFW_* functions to
> call the functions in ofw_fdt.c directly. Is there any other way?

I would try to replace the function declarations in openfirm.h with 
inline functions which call the ofw_fdt.c functions.