linux-kernel - [PATCH v4 3/3] clocksource: timer-riscv: Set CLOCK_EVT_FEAT

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Date:   Tue, 29 Nov 2022 19:33:13 +0530
From:   Anup Patel <apatel@...tanamicro.com>
To:     Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Palmer Dabbelt <palmer@...belt.com>,
        Paul Walmsley <paul.walmsley@...ive.com>,
        Daniel Lezcano <daniel.lezcano@...aro.org>,
        Thomas Gleixner <tglx@...utronix.de>
Cc:     Andrew Jones <ajones@...tanamicro.com>,
        Atish Patra <atishp@...shpatra.org>,
        Samuel Holland <samuel@...lland.org>,
        Conor Dooley <conor.dooley@...rochip.com>,
        Anup Patel <anup@...infault.org>, devicetree@...r.kernel.org,
        linux-riscv@...ts.infradead.org, linux-kernel@...r.kernel.org,
        Anup Patel <apatel@...tanamicro.com>
Subject: [PATCH v4 3/3] clocksource: timer-riscv: Set CLOCK_EVT_FEAT_C3STOP based on DT

We should set CLOCK_EVT_FEAT_C3STOP for a clock_event_device only
when riscv,timer-cant-wake-up DT property is present in the RISC-V
timer DT node.

This way CLOCK_EVT_FEAT_C3STOP feature is set for clock_event_device
based on RISC-V platform capabilities rather than having it set for
all RISC-V platforms.

Signed-off-by: Anup Patel <apatel@...tanamicro.com>
---
 drivers/clocksource/timer-riscv.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/drivers/clocksource/timer-riscv.c b/drivers/clocksource/timer-riscv.c
index 969a552da8d2..0c8bdd168a45 100644
--- a/drivers/clocksource/timer-riscv.c
+++ b/drivers/clocksource/timer-riscv.c
@@ -28,6 +28,7 @@
 #include <asm/timex.h>
 
 static DEFINE_STATIC_KEY_FALSE(riscv_sstc_available);
+static bool riscv_timer_cant_wake_cpu;
 
 static int riscv_clock_next_event(unsigned long delta,
 		struct clock_event_device *ce)
@@ -51,7 +52,7 @@ static int riscv_clock_next_event(unsigned long delta,
 static unsigned int riscv_clock_event_irq;
 static DEFINE_PER_CPU(struct clock_event_device, riscv_clock_event) = {
 	.name			= "riscv_timer_clockevent",
-	.features		= CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_FEAT_C3STOP,
+	.features		= CLOCK_EVT_FEAT_ONESHOT,
 	.rating			= 100,
 	.set_next_event		= riscv_clock_next_event,
 };
@@ -85,6 +86,8 @@ static int riscv_timer_starting_cpu(unsigned int cpu)
 
 	ce->cpumask = cpumask_of(cpu);
 	ce->irq = riscv_clock_event_irq;
+	if (riscv_timer_cant_wake_cpu)
+		ce->features |= CLOCK_EVT_FEAT_C3STOP;
 	clockevents_config_and_register(ce, riscv_timebase, 100, 0x7fffffff);
 
 	enable_percpu_irq(riscv_clock_event_irq,
@@ -139,6 +142,13 @@ static int __init riscv_timer_init_dt(struct device_node *n)
 	if (cpuid != smp_processor_id())
 		return 0;
 
+	child = of_find_compatible_node(NULL, NULL, "riscv,timer");
+	if (child) {
+		riscv_timer_cant_wake_cpu = of_property_read_bool(child,
+						"riscv,timer-cant-wake-cpu");
+		of_node_put(child);
+	}
+
 	domain = NULL;
 	child = of_get_compatible_child(n, "riscv,cpu-intc");
 	if (!child) {
-- 
2.34.1