[PATCH 06/13] include: sbi: Introduce nascent_init() platform callback

[Anup Patel]

On Tue, Feb 8, 2022 at 2:38 PM Atish Patra <atishp at atishpatra.org> wrote:
>
> On Tue, Jan 4, 2022 at 2:13 AM Anup Patel <apatel at ventanamicro.com> wrote:
> >
> > We introduce nascent_init() platform callback which will allow
> > platforms to do very early initialization of platform specific
> > per-HART CSRs and per-HART devices.
> >
> > Signed-off-by: Anup Patel <anup.patel at wdc.com>
> > Signed-off-by: Anup Patel <apatel at ventanamicro.com>
> > ---
> >  include/sbi/sbi_platform.h | 17 +++++++++++++++++
> >  lib/sbi/sbi_init.c         |  8 ++++++++
> >  2 files changed, 25 insertions(+)
> >
> > diff --git a/include/sbi/sbi_platform.h b/include/sbi/sbi_platform.h
> > index 4d192f2..e097785 100644
> > --- a/include/sbi/sbi_platform.h
> > +++ b/include/sbi/sbi_platform.h
> > @@ -64,6 +64,9 @@ enum sbi_platform_features {
> >
> >  /** Platform functions */
> >  struct sbi_platform_operations {
> > +       /* Platform nascent initialization */
> > +       int (*nascent_init)(void);
> > +
> >         /** Platform early initialization */
> >         int (*early_init)(bool cold_boot);
> >         /** Platform final initialization */
> > @@ -299,6 +302,20 @@ static inline bool sbi_platform_hart_invalid(const struct sbi_platform *plat,
> >         return FALSE;
> >  }
> >
> > +/**
> > + * Nascent (very early) initialization for current HART
> > + *
>
> We probably need a better comment to differentiate between Nascent & early init.
> Without that, platform vendors may just use this instead of early init.

Okay, I will add more details in the comment here.

Regards,
Anup

>
> > + * @param plat pointer to struct sbi_platform
> > + *
> > + * @return 0 on success and negative error code on failure
> > + */
> > +static inline int sbi_platform_nascent_init(const struct sbi_platform *plat)
> > +{
> > +       if (plat && sbi_platform_ops(plat)->nascent_init)
> > +               return sbi_platform_ops(plat)->nascent_init();
> > +       return 0;
> > +}
> > +
> >  /**
> >   * Early initialization for current HART
> >   *
> > diff --git a/lib/sbi/sbi_init.c b/lib/sbi/sbi_init.c
> > index 83043c5..27d03a7 100644
> > --- a/lib/sbi/sbi_init.c
> > +++ b/lib/sbi/sbi_init.c
> > @@ -494,6 +494,14 @@ void __noreturn sbi_init(struct sbi_scratch *scratch)
> >         if (next_mode_supported && atomic_xchg(&coldboot_lottery, 1) == 0)
> >                 coldboot = TRUE;
> >
> > +       /*
> > +        * Do platform specific nascent (very early) initialization so
> > +        * that platform can initialize platform specific per-HART CSRs
> > +        * or per-HART devices.
> > +        */
> > +       if (sbi_platform_nascent_init(plat))
> > +               sbi_hart_hang();
> > +
> >         if (coldboot)
> >                 init_coldboot(scratch, hartid);
> >         else
> > --
> > 2.25.1
> >
>
> Other than that, LGTM.
>
> Reviewed-by: Atish Patra <atishp at rivosinc.com>
>
> --
> Regards,
> Atish