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

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Date:   Sun, 11 Dec 2022 21:58:43 +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>,
        Geert Uytterhoeven <geert+renesas@...der.be>,
        Conor Dooley <conor.dooley@...rochip.com>,
        Heiko Stuebner <heiko@...ech.de>
Cc:     linux-riscv@...ts.infradead.org, Anup Patel <anup@...infault.org>,
        linux-renesas-soc@...r.kernel.org, linux-kernel@...r.kernel.org,
        Prabhakar <prabhakar.csengg@...il.com>,
        Biju Das <biju.das.jz@...renesas.com>,
        Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
Subject: [RFC PATCH] 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>
---
 arch/riscv/Kconfig                | 1 -
 arch/riscv/kernel/time.c          | 9 ---------
 drivers/clocksource/timer-riscv.c | 7 +++++++
 3 files changed, 7 insertions(+), 10 deletions(-)

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 7ea12de636bd..b269e062c1b1 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 969a552da8d2..7ec9668cd36d 100644
--- a/drivers/clocksource/timer-riscv.c
+++ b/drivers/clocksource/timer-riscv.c
@@ -29,6 +29,12 @@
 
 static DEFINE_STATIC_KEY_FALSE(riscv_sstc_available);
 
+#ifdef CONFIG_GENERIC_GETTIMEOFDAY
+static enum vdso_clock_mode vdso_default = VDSO_CLOCKMODE_ARCHTIMER;
+#else
+static enum vdso_clock_mode vdso_default = VDSO_CLOCKMODE_NONE;
+#endif /* CONFIG_GENERIC_GETTIMEOFDAY */
+
 static int riscv_clock_next_event(unsigned long delta,
 		struct clock_event_device *ce)
 {
@@ -158,6 +164,7 @@ static int __init riscv_timer_init_dt(struct device_node *n)
 		return -ENODEV;
 	}
 
+	riscv_clocksource.vdso_clock_mode = vdso_default;
 	pr_info("%s: Registering clocksource cpuid [%d] hartid [%lu]\n",
 	       __func__, cpuid, hartid);
 	error = clocksource_register_hz(&riscv_clocksource, riscv_timebase);
-- 
2.25.1