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

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Date:   Thu, 29 Dec 2022 22:46:01 +0000
From:   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,
        Prabhakar <prabhakar.csengg@...il.com>,
        Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>,
        Samuel Holland <samuel@...lland.org>
Subject: [PATCH v2] clocksource/drivers/riscv: Get rid of clocksource_arch_init() callback

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(-)

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