[PATCH 19/25] clocksource/drivers/riscv_timer: Provide the sched_clock

[PATCH 19/25] clocksource/drivers/riscv_timer: Provide the sched_clock

[Daniel Lezcano]

From: Anup Patel <anup@brainfault.org>

Currently, we don't have a sched_clock registered for RISC-V systems.
This means Linux time keeping will use jiffies (running at HZ) as the
default sched_clock.

To avoid this, we explicity provide sched_clock using RISC-V rdtime
instruction (similar to riscv_timer clocksource).

Signed-off-by: Anup Patel <anup@brainfault.org>
Reviewed-by: Palmer Dabbelt <palmer@sifive.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
---
 drivers/clocksource/Kconfig       | 2 +-
 drivers/clocksource/riscv_timer.c | 9 +++++++++
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
index c57b156f49a2..a4ae339e0101 100644
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig
@@ -599,7 +599,7 @@ config ATCPIT100_TIMER
 
 config RISCV_TIMER
 	bool "Timer for the RISC-V platform"
-	depends on RISCV
+	depends on GENERIC_SCHED_CLOCK && RISCV
 	default y
 	select TIMER_PROBE
 	select TIMER_OF
diff --git a/drivers/clocksource/riscv_timer.c b/drivers/clocksource/riscv_timer.c
index 084e97dc10ed..431892200a08 100644
--- a/drivers/clocksource/riscv_timer.c
+++ b/drivers/clocksource/riscv_timer.c
@@ -8,6 +8,7 @@
 #include <linux/cpu.h>
 #include <linux/delay.h>
 #include <linux/irq.h>
+#include <linux/sched_clock.h>
 #include <asm/smp.h>
 #include <asm/sbi.h>
 
@@ -49,6 +50,11 @@ static unsigned long long riscv_clocksource_rdtime(struct clocksource *cs)
 	return get_cycles64();
 }
 
+static u64 riscv_sched_clock(void)
+{
+	return get_cycles64();
+}
+
 static DEFINE_PER_CPU(struct clocksource, riscv_clocksource) = {
 	.name		= "riscv_clocksource",
 	.rating		= 300,
@@ -97,6 +103,9 @@ static int __init riscv_timer_init_dt(struct device_node *n)
 	cs = per_cpu_ptr(&riscv_clocksource, cpuid);
 	clocksource_register_hz(cs, riscv_timebase);
 
+	sched_clock_register(riscv_sched_clock,
+			BITS_PER_LONG, riscv_timebase);
+
 	error = cpuhp_setup_state(CPUHP_AP_RISCV_TIMER_STARTING,
 			 "clockevents/riscv/timer:starting",
 			 riscv_timer_starting_cpu, riscv_timer_dying_cpu);
-- 
2.17.1


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[PATCH 20/25] clocksource/drivers/riscv: Change name riscv_timer to timer-riscv

[Daniel Lezcano]

In order to unify the names in this directory, let's rename the driver to be
prefixed with timer-*

Reviewed-by: Palmer Dabbelt <palmer@sifive.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
---
 drivers/clocksource/Makefile                         | 2 +-
 drivers/clocksource/{riscv_timer.c => timer-riscv.c} | 0
 2 files changed, 1 insertion(+), 1 deletion(-)
 rename drivers/clocksource/{riscv_timer.c => timer-riscv.c} (100%)

diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile
index dd9138104568..ddf697b29df9 100644
--- a/drivers/clocksource/Makefile
+++ b/drivers/clocksource/Makefile
@@ -78,6 +78,6 @@ obj-$(CONFIG_H8300_TPU)			+= h8300_tpu.o
 obj-$(CONFIG_CLKSRC_ST_LPC)		+= clksrc_st_lpc.o
 obj-$(CONFIG_X86_NUMACHIP)		+= numachip.o
 obj-$(CONFIG_ATCPIT100_TIMER)		+= timer-atcpit100.o
-obj-$(CONFIG_RISCV_TIMER)		+= riscv_timer.o
+obj-$(CONFIG_RISCV_TIMER)		+= timer-riscv.o
 obj-$(CONFIG_CSKY_MP_TIMER)		+= timer-mp-csky.o
 obj-$(CONFIG_GX6605S_TIMER)		+= timer-gx6605s.o
diff --git a/drivers/clocksource/riscv_timer.c b/drivers/clocksource/timer-riscv.c
similarity index 100%
rename from drivers/clocksource/riscv_timer.c
rename to drivers/clocksource/timer-riscv.c
-- 
2.17.1


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