[PATCH v2] lib: sbi: Add option to select boot hart

[Anup Patel]

On Fri, Dec 2, 2022 at 1:21 PM Anup Patel <apatel at ventanamicro.com> wrote:
>
> On Fri, Dec 2, 2022 at 12:10 PM Wei Liang Lim
> <weiliang.lim at starfivetech.com> wrote:
> >
> > In certain scenario, user needs to select a particular hart ID as the boot hart. This option provide the flexibility for user to select the preferred boot hart.
> >
> > Signed-off-by: Wei Liang Lim <weiliang.lim at starfivetech.com>
> > Reviewed-by: Chee Hong Ang <cheehong.ang at starfivetech.com>
> > Reviewed-by: Jun Liang Tan <junliang.tan at starfivetech.com>
> > ---
> >  firmware/objects.mk | 4 ++++
> >  lib/sbi/sbi_init.c  | 6 ++++++
> >  2 files changed, 10 insertions(+)
> >
> > diff --git a/firmware/objects.mk b/firmware/objects.mk
> > index a1704c4..2b41718 100644
> > --- a/firmware/objects.mk
> > +++ b/firmware/objects.mk
> > @@ -28,6 +28,10 @@ ifdef FW_TEXT_START
> >  firmware-genflags-y += -DFW_TEXT_START=$(FW_TEXT_START)
> >  endif
> >
> > +ifdef FW_BOOT_HART_ID
> > +firmware-genflags-y += -DFW_BOOT_HART_ID=$(FW_BOOT_HART_ID)
> > +endif
> > +
> >  ifdef FW_FDT_PATH
> >  firmware-genflags-y += -DFW_FDT_PATH=\"$(FW_FDT_PATH)\"
> >  ifdef FW_FDT_PADDING
> > diff --git a/lib/sbi/sbi_init.c b/lib/sbi/sbi_init.c
> > index a8500e5..28698f1 100644
> > --- a/lib/sbi/sbi_init.c
> > +++ b/lib/sbi/sbi_init.c
> > @@ -447,7 +447,9 @@ static void __noreturn init_warmboot(struct sbi_scratch *scratch, u32 hartid)
> >                              scratch->next_mode, FALSE);
> >  }
> >
> > +#ifndef FW_BOOT_HART_ID
> >  static atomic_t coldboot_lottery = ATOMIC_INITIALIZER(0);
> > +#endif
> >
> >  /**
> >   * Initialize OpenSBI library for current HART and jump to next
> > @@ -498,7 +500,11 @@ void __noreturn sbi_init(struct sbi_scratch *scratch)
> >          * HARTs which satisfy above condition.
> >          */
> >
> > +#ifdef FW_BOOT_HART_ID
> > +       if (next_mode_supported && hartid == FW_BOOT_HART_ID)
> > +#else
>
> This breaks the CPU hotplug for boot HART.
>
> In other words, the boot HART will now always take coldboot path when
> it is stopped (sbi_hsm_hart_stop()) and started (sbi_hsm_hart_start())
> at runtime.

Can you try the two experimental patches from preferred_cold_boot_hart_v1
branch at: https://github.com/avpatel/opensbi.git ?

You will need to implement your platform specific override on top of these
patches to decide which HARTs are allowed to do cold boot. If it works
for you then include these patches in your v3 patches.

Regards,
Anup

>
> >         if (next_mode_supported && atomic_xchg(&coldboot_lottery, 1) == 0)
> > +#endif
> >                 coldboot = TRUE;
> >
> >         /*
> > --
> > 2.25.1
> >
> >
> > --
> > opensbi mailing list
> > opensbi at lists.infradead.org
> > http://lists.infradead.org/mailman/listinfo/opensbi
>
> Regards,
> Anup