Re: [PATCH 14/24] RISC-V: ACPI: smpboot: Add function to retrieve the hartid

Sunil V L
2023-02-13T17:00:45Z

On Thu, Feb 09, 2023 at 08:30:40PM +0000, Conor Dooley wrote:
> Hey Sunil, Drew,
>
> @drew, a question below that I'm sorta aiming at you...
>
> On Mon, Jan 30, 2023 at 11:52:15PM +0530, Sunil V L wrote:
> > hartid is in RINTC structuire in MADT table. Instead of parsing
>
> Nit: missing articles before RINTC and MADT. Also typo "structure".
>
> Perhaps you'd benefit from a spell checker in your git editor.
>
Okay.

> > the ACPI table every time we need for a cpu, cache it and provide
> > a function to read it.
> >
> > This is similar to acpi_get_madt_gicc() in arm64.
>
> -ENOTFOUND, do you mean acpi_cpu_get_madt_gicc()?
>
Yes. Will update.

> >
> > Signed-off-by: Sunil V L <sunilvl@ventanamicro.com>
> > ---
> > arch/riscv/include/asm/acpi.h | 14 +++++++++++++-
> > arch/riscv/kernel/smpboot.c | 21 +++++++++++++++++++++
> > 2 files changed, 34 insertions(+), 1 deletion(-)
> >
> > diff --git a/arch/riscv/include/asm/acpi.h b/arch/riscv/include/asm/acpi.h
> > index d1f1e53ec657..69a880b7257a 100644
> > --- a/arch/riscv/include/asm/acpi.h
> > +++ b/arch/riscv/include/asm/acpi.h
> > @@ -65,6 +65,18 @@ int acpi_numa_get_nid(unsigned int cpu);
> > static inline int acpi_numa_get_nid(unsigned int cpu) { return NUMA_NO_NODE; }
> > #endif /* CONFIG_ACPI_NUMA */
> >
> > -#endif
> > +struct acpi_madt_rintc *acpi_get_madt_rintc(int cpu);
> > +struct acpi_madt_rintc *acpi_cpu_get_madt_rintc(int cpu);
> > +static inline u32 get_acpi_id_for_cpu(int cpu)
> > +{
> > + return acpi_cpu_get_madt_rintc(cpu)->uid;
> > +}
> > +#else
> > +static inline u32 get_acpi_id_for_cpu(int cpu)
> > +{
> > + return -1;
> > +}
> > +
> > +#endif /* CONFIG_ACPI */
> >
> > #endif /*_ASM_ACPI_H*/
> > diff --git a/arch/riscv/kernel/smpboot.c b/arch/riscv/kernel/smpboot.c
> > index e48cf88d0bc1..3a8b7a9eb5ac 100644
> > --- a/arch/riscv/kernel/smpboot.c
> > +++ b/arch/riscv/kernel/smpboot.c
> > @@ -73,6 +73,25 @@ void __init smp_prepare_cpus(unsigned int max_cpus)
> >
> > #ifdef CONFIG_ACPI
> > static unsigned int cpu_count = 1;
> > +static unsigned int intc_count;
> > +static struct acpi_madt_rintc cpu_madt_rintc[NR_CPUS];
> > +
> > +struct acpi_madt_rintc *acpi_get_madt_rintc(int cpu)
> > +{
> > + return &cpu_madt_rintc[cpu];
> > +}
> > +
> > +struct acpi_madt_rintc *acpi_cpu_get_madt_rintc(int cpu)
> > +{
> > + int i;
>
> Since we are C11 now, you don't even need to declare this outside of the
> loop, right?
>
Okay.

> > +
> > + for (i = 0; i < NR_CPUS; i++) {
>
> @drew, perhaps you know since you were fiddling not too long ago with
> cpumask stuff - at what point does for_each_possible_cpu() become
> usable?
> I had a bit of a poke & couldn't immediately tell if it'd be okay to use
> it here.
>
It should be possible. Thanks!

> > + if (riscv_hartid_to_cpuid(cpu_madt_rintc[i].hart_id) == cpu)
> > + return &cpu_madt_rintc[i];
> > + }
> > + return NULL;
>
> Another nit: newline before return please :)
>
Sure.

Thanks,
Sunil