This series is a simple improvement for timer-clint and timer-riscv:
Add set_state_shutdown for timer-clint, this hook is used when
switching clockevent from timer-clint to another timer.
Add set_state_oneshot_stopped for both timer-clint and timer-riscv,
this hook is to avoid spurious timer interrupts when KTIME_MAX is
usd. Check commit 8fff52fd5093 ("clockevents: Introduce
CLOCK_EVT_STATE_ONESHOT_STOPPED state") for more information.
Jisheng Zhang (3):
clocksource/drivers/timer-riscv: Add set_state_oneshot_stopped
clocksource/drivers/timer-clint: Add set_state_shutdown
clocksource/drivers/timer-clint: Add set_state_oneshot_stopped
drivers/clocksource/timer-clint.c | 19 +++++++++++++++----
drivers/clocksource/timer-riscv.c | 11 ++++++-----
2 files changed, 21 insertions(+), 9 deletions(-)
--
2.43.0
To avoid spurious timer interrupts when KTIME_MAX is used, we need to
configure set_state_oneshot_stopped(). Although implementing this is
optional, it still affects things like power management for the extra
timer interrupt.
Check commit 8fff52fd5093 ("clockevents: Introduce
CLOCK_EVT_STATE_ONESHOT_STOPPED state") for more information.
Signed-off-by: Jisheng Zhang <[email protected]>
---
drivers/clocksource/timer-riscv.c | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)
diff --git a/drivers/clocksource/timer-riscv.c b/drivers/clocksource/timer-riscv.c
index 48ce50c5f5e6..e661fc037337 100644
--- a/drivers/clocksource/timer-riscv.c
+++ b/drivers/clocksource/timer-riscv.c
@@ -69,11 +69,12 @@ static int riscv_clock_shutdown(struct clock_event_device *evt)
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,
- .rating = 100,
- .set_next_event = riscv_clock_next_event,
- .set_state_shutdown = riscv_clock_shutdown,
+ .name = "riscv_timer_clockevent",
+ .features = CLOCK_EVT_FEAT_ONESHOT,
+ .rating = 100,
+ .set_next_event = riscv_clock_next_event,
+ .set_state_shutdown = riscv_clock_shutdown,
+ .set_state_oneshot_stopped = riscv_clock_shutdown,
};
/*
--
2.43.0
Add clocksource detach/shutdown callback to disable RISC-V timer interrupt when
switching out clockevent from clint timer to another timer.
Signed-off-by: Jisheng Zhang <[email protected]>
---
drivers/clocksource/timer-clint.c | 18 ++++++++++++++----
1 file changed, 14 insertions(+), 4 deletions(-)
diff --git a/drivers/clocksource/timer-clint.c b/drivers/clocksource/timer-clint.c
index 09fd292eb83d..56cf6c672e6d 100644
--- a/drivers/clocksource/timer-clint.c
+++ b/drivers/clocksource/timer-clint.c
@@ -119,11 +119,21 @@ static int clint_clock_next_event(unsigned long delta,
return 0;
}
+static int clint_clock_shutdown(struct clock_event_device *evt)
+{
+ void __iomem *r = clint_timer_cmp +
+ cpuid_to_hartid_map(smp_processor_id());
+
+ writeq_relaxed(ULONG_MAX, r);
+ return 0;
+}
+
static DEFINE_PER_CPU(struct clock_event_device, clint_clock_event) = {
- .name = "clint_clockevent",
- .features = CLOCK_EVT_FEAT_ONESHOT,
- .rating = 100,
- .set_next_event = clint_clock_next_event,
+ .name = "clint_clockevent",
+ .features = CLOCK_EVT_FEAT_ONESHOT,
+ .rating = 100,
+ .set_next_event = clint_clock_next_event,
+ .set_state_shutdown = clint_clock_shutdown,
};
static int clint_timer_starting_cpu(unsigned int cpu)
--
2.43.0
To avoid spurious timer interrupts when KTIME_MAX is used, we need to
configure set_state_oneshot_stopped(). Although implementing this is
optional, it still affects things like power management for the extra
timer interrupt.
Check commit 8fff52fd5093 ("clockevents: Introduce
CLOCK_EVT_STATE_ONESHOT_STOPPED state") for more information.
Signed-off-by: Jisheng Zhang <[email protected]>
---
drivers/clocksource/timer-clint.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/drivers/clocksource/timer-clint.c b/drivers/clocksource/timer-clint.c
index 56cf6c672e6d..f5c04520d6b1 100644
--- a/drivers/clocksource/timer-clint.c
+++ b/drivers/clocksource/timer-clint.c
@@ -134,6 +134,7 @@ static DEFINE_PER_CPU(struct clock_event_device, clint_clock_event) = {
.rating = 100,
.set_next_event = clint_clock_next_event,
.set_state_shutdown = clint_clock_shutdown,
+ .set_state_oneshot_stopped = clint_clock_shutdown,
};
static int clint_timer_starting_cpu(unsigned int cpu)
--
2.43.0
Hi Jisheng,
On 2024-03-27 10:35 AM, Jisheng Zhang wrote:
> Add clocksource detach/shutdown callback to disable RISC-V timer interrupt when
> switching out clockevent from clint timer to another timer.
>
> Signed-off-by: Jisheng Zhang <[email protected]>
> ---
> drivers/clocksource/timer-clint.c | 18 ++++++++++++++----
> 1 file changed, 14 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/clocksource/timer-clint.c b/drivers/clocksource/timer-clint.c
> index 09fd292eb83d..56cf6c672e6d 100644
> --- a/drivers/clocksource/timer-clint.c
> +++ b/drivers/clocksource/timer-clint.c
> @@ -119,11 +119,21 @@ static int clint_clock_next_event(unsigned long delta,
> return 0;
> }
>
> +static int clint_clock_shutdown(struct clock_event_device *evt)
> +{
> + void __iomem *r = clint_timer_cmp +
> + cpuid_to_hartid_map(smp_processor_id());
> +
> + writeq_relaxed(ULONG_MAX, r);
This needs to be ULLONG_MAX to produce a 64-bit value on riscv32.
Regards,
Samuel
> + return 0;
> +}
> +
> static DEFINE_PER_CPU(struct clock_event_device, clint_clock_event) = {
> - .name = "clint_clockevent",
> - .features = CLOCK_EVT_FEAT_ONESHOT,
> - .rating = 100,
> - .set_next_event = clint_clock_next_event,
> + .name = "clint_clockevent",
> + .features = CLOCK_EVT_FEAT_ONESHOT,
> + .rating = 100,
> + .set_next_event = clint_clock_next_event,
> + .set_state_shutdown = clint_clock_shutdown,
> };
>
> static int clint_timer_starting_cpu(unsigned int cpu)