linux-kernel - Re: [PATCH v2] clocksource/drivers/riscv: Get rid of clocksource_arch

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Message-ID: <CA+V-a8t38vHuBd+GJs5_643Jp5L6u6ci7NWVjRn53iwA445ODA@mail.gmail.com>
Date:   Sat, 14 Jan 2023 18:58:52 +0000
From:   "Lad, Prabhakar" <prabhakar.csengg@...il.com>
To:     Paul Walmsley <paul.walmsley@...ive.com>,
        Palmer Dabbelt <palmer@...belt.com>,
        Albert Ou <aou@...s.berkeley.edu>,
        Daniel Lezcano <daniel.lezcano@...aro.org>,
        Thomas Gleixner <tglx@...utronix.de>
Cc:     linux-riscv@...ts.infradead.org,
        Geert Uytterhoeven <geert@...ux-m68k.org>,
        linux-kernel@...r.kernel.org, linux-renesas-soc@...r.kernel.org,
        Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>,
        Samuel Holland <samuel@...lland.org>
Subject: Re: [PATCH v2] clocksource/drivers/riscv: Get rid of
 clocksource_arch_init() callback

On Thu, Dec 29, 2022 at 10:50 PM Prabhakar <prabhakar.csengg@...il.com> wrote:
>
> From: Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
>
> Having a clocksource_arch_init() callback always sets vdso_clock_mode to
> VDSO_CLOCKMODE_ARCHTIMER if GENERIC_GETTIMEOFDAY is enabled, this is
> required for the riscv-timer.
>
> This works for platforms where just riscv-timer clocksource is present.
> On platforms where other clock sources are available we want them to
> register with vdso_clock_mode set to VDSO_CLOCKMODE_NONE.
>
> On the Renesas RZ/Five SoC OSTM block can be used as clocksource [0], to
> avoid multiple clock sources being registered as VDSO_CLOCKMODE_ARCHTIMER
> move setting of vdso_clock_mode in the riscv-timer driver instead of doing
> this in clocksource_arch_init() callback as done similarly for ARM/64
> architecture.
>
> [0] drivers/clocksource/renesas-ostm.c
>
> Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
> Tested-by: Samuel Holland <samuel@...lland.org>
> ---
> RFC -> v2
> * Dropped vdso_default static global variable
> * Used IS_ENABLED() macro
> * Included Tested-by from Samuel
>
> RFC:
> https://patchwork.kernel.org/project/linux-renesas-soc/patch/20221211215843.24024-1-prabhakar.mahadev-lad.rj@bp.renesas.com/
> ---
>  arch/riscv/Kconfig                | 1 -
>  arch/riscv/kernel/time.c          | 9 ---------
>  drivers/clocksource/timer-riscv.c | 5 +++++
>  3 files changed, 5 insertions(+), 10 deletions(-)
>
Gentle ping.

Cheers,
Prabhakar

> diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
> index e2b656043abf..9c687da7756d 100644
> --- a/arch/riscv/Kconfig
> +++ b/arch/riscv/Kconfig
> @@ -12,7 +12,6 @@ config 32BIT
>
>  config RISCV
>         def_bool y
> -       select ARCH_CLOCKSOURCE_INIT
>         select ARCH_ENABLE_HUGEPAGE_MIGRATION if HUGETLB_PAGE && MIGRATION
>         select ARCH_ENABLE_SPLIT_PMD_PTLOCK if PGTABLE_LEVELS > 2
>         select ARCH_HAS_BINFMT_FLAT
> diff --git a/arch/riscv/kernel/time.c b/arch/riscv/kernel/time.c
> index 8217b0f67c6c..42bee305e997 100644
> --- a/arch/riscv/kernel/time.c
> +++ b/arch/riscv/kernel/time.c
> @@ -30,12 +30,3 @@ void __init time_init(void)
>         of_clk_init(NULL);
>         timer_probe();
>  }
> -
> -void clocksource_arch_init(struct clocksource *cs)
> -{
> -#ifdef CONFIG_GENERIC_GETTIMEOFDAY
> -       cs->vdso_clock_mode = VDSO_CLOCKMODE_ARCHTIMER;
> -#else
> -       cs->vdso_clock_mode = VDSO_CLOCKMODE_NONE;
> -#endif
> -}
> diff --git a/drivers/clocksource/timer-riscv.c b/drivers/clocksource/timer-riscv.c
> index 55dad7965f43..c416e5e934bf 100644
> --- a/drivers/clocksource/timer-riscv.c
> +++ b/drivers/clocksource/timer-riscv.c
> @@ -77,6 +77,11 @@ static struct clocksource riscv_clocksource = {
>         .mask           = CLOCKSOURCE_MASK(64),
>         .flags          = CLOCK_SOURCE_IS_CONTINUOUS,
>         .read           = riscv_clocksource_rdtime,
> +#if IS_ENABLED(CONFIG_GENERIC_GETTIMEOFDAY)
> +       .vdso_clock_mode = VDSO_CLOCKMODE_ARCHTIMER,
> +#else
> +       .vdso_clock_mode = VDSO_CLOCKMODE_NONE,
> +#endif
>  };
>
>  static int riscv_timer_starting_cpu(unsigned int cpu)
> --
> 2.25.1
>