Re: [PATCH v2] clocksource/drivers/riscv: Get rid of clocksource_arch_init() callback

From: Conor Dooley <conor.dooley@microchip.com>
To: Prabhakar <prabhakar.csengg@gmail.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Albert Ou <aou@eecs.berkeley.edu>,
	Daniel Lezcano <daniel.lezcano@linaro.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	<linux-riscv@lists.infradead.org>,
	Geert Uytterhoeven <geert@linux-m68k.org>,
	<linux-kernel@vger.kernel.org>,
	<linux-renesas-soc@vger.kernel.org>,
	Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>,
	Samuel Holland <samuel@sholland.org>
Subject: Re: [PATCH v2] clocksource/drivers/riscv: Get rid of clocksource_arch_init() callback
Date: Fri, 20 Jan 2023 14:09:35 +0000	[thread overview]
Message-ID: <Y8qgn5FVtro0nAlp@wendy> (raw)
In-Reply-To: <20221229224601.103851-1-prabhakar.mahadev-lad.rj@bp.renesas.com>

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On Thu, Dec 29, 2022 at 10:46:01PM +0000, Prabhakar wrote:
> From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.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@bp.renesas.com>
> Tested-by: Samuel Holland <samuel@sholland.org>
> ---
> RFC -> v2
> * Dropped vdso_default static global variable

> * Used IS_ENABLED() macro

Not sure it really makes much difference here either way, but increased
coverage is always good I suppose.

rv32 is the user for the !GENERIC_GETTIMEOFDAY patch IIRC and nothing
seemed obviously amiss there to me either.

Reviewed-by: Conor Dooley <conor.dooley@microchip.com>

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