From: Noam Camus <noamc@xxxxxxxxxx>
ARC Timers so far have been handled as "legacy" w/o explicit description
in DT. This poses challenge for newer platforms wanting to use them.
This series will eventually help move timers over to DT.
This patch does a small change of using a CPU notifier to set clockevent
on non-boot CPUs. So explicit setup is done only on boot CPU (which will
later be done by DT)
This also helps
- wean away from arc_request_percpu_irq() which has a design flaw as
noted in c6317bc7c5ab
("ARCv2: perf: Ensure perf intr gets enabled on all cores")
- Remove exposing timer function to smp.c
Cc: Daniel Lezcano <daniel.lezcano at linaro.org>
Signed-off-by: Noam Camus <noamc at ezchip.com>
[vgupta: broken off from a bigger patch]
Signed-off-by: Vineet Gupta <vgupta at synopsys.com>
Signed-off-by: Vineet Gupta <vgupta at synopsys.com>
---
arch/arc/include/asm/irq.h | 1 -
arch/arc/kernel/smp.c | 2 --
arch/arc/kernel/time.c | 48 ++++++++++++++++++++++++++++++++++++++--------
3 files changed, 40 insertions(+), 11 deletions(-)
diff --git a/arch/arc/include/asm/irq.h b/arch/arc/include/asm/irq.h
index 4fd7d62a6e30..0c86f0787bcd 100644
--- a/arch/arc/include/asm/irq.h
+++ b/arch/arc/include/asm/irq.h
@@ -27,7 +27,6 @@
#include <asm-generic/irq.h>
extern void arc_init_IRQ(void);
-void arc_local_timer_setup(void);
void arc_request_percpu_irq(int irq, int cpu,
irqreturn_t (*isr)(int irq, void *dev),
const char *irq_nm, void *percpu_dev);
diff --git a/arch/arc/kernel/smp.c b/arch/arc/kernel/smp.c
index ef6e9e15b82a..ea790f1c1107 100644
--- a/arch/arc/kernel/smp.c
+++ b/arch/arc/kernel/smp.c
@@ -138,8 +138,6 @@ void start_kernel_secondary(void)
if (machine_desc->init_per_cpu)
machine_desc->init_per_cpu(cpu);
- arc_local_timer_setup();
-
local_irq_enable();
preempt_disable();
cpu_startup_entry(CPUHP_ONLINE);
diff --git a/arch/arc/kernel/time.c b/arch/arc/kernel/time.c
index 156d9833ff84..bdfc621d5d85 100644
--- a/arch/arc/kernel/time.c
+++ b/arch/arc/kernel/time.c
@@ -183,6 +183,8 @@ static struct clocksource arc_counter = {
/********** Clock Event Device *********/
+static int arc_timer_irq = TIMER0_IRQ;
+
/*
* Arm the timer to interrupt after @cycles
* The distinction for oneshot/periodic is done in arc_event_timer_ack() below
@@ -244,21 +246,52 @@ static irqreturn_t timer_irq_handler(int irq, void *dev_id)
return IRQ_HANDLED;
}
+static int arc_timer_cpu_notify(struct notifier_block *self,
+ unsigned long action, void *hcpu)
+{
+ struct clock_event_device *evt = this_cpu_ptr(&arc_clockevent_device);
+
+ evt->cpumask = cpumask_of(smp_processor_id());
+
+ switch (action & ~CPU_TASKS_FROZEN) {
+ case CPU_STARTING:
+ clockevents_config_and_register(evt, arc_get_core_freq(),
+ 0, ULONG_MAX);
+ enable_percpu_irq(arc_timer_irq, 0);
+ break;
+ case CPU_DYING:
+ disable_percpu_irq(arc_timer_irq);
+ break;
+ }
+
+ return NOTIFY_OK;
+}
+
+static struct notifier_block nps_timer_cpu_nb = {
+ .notifier_call = arc_timer_cpu_notify,
+};
+
/*
- * Setup the local event timer for @cpu
+ * clockevent setup for boot CPU
*/
-void arc_local_timer_setup()
+static void __init arc_clockevent_setup()
{
struct clock_event_device *evt = this_cpu_ptr(&arc_clockevent_device);
- int cpu = smp_processor_id();
- evt->cpumask = cpumask_of(cpu);
+ register_cpu_notifier(&arc_timer_cpu_nb);
+
+ evt->cpumask = cpumask_of(smp_processor_id());
clockevents_config_and_register(evt, arc_get_core_freq(),
0, ARC_TIMER_MAX);
/* setup the per-cpu timer IRQ handler - for all cpus */
- arc_request_percpu_irq(TIMER0_IRQ, cpu, timer_irq_handler,
- "Timer0 (per-cpu-tick)", evt);
+ request_percpu_irq(arc_timer_irq, timer_irq_handler,
+ "Timer0 (per-cpu-tick)", evt);
+
+ enable_percpu_irq(arc_timer_irq, 0);
+
+ if (ret)
+ pr_err("Unable to register interrupt\n");
}
/*
@@ -283,6 +316,5 @@ void __init time_init(void)
*/
clocksource_register_hz(&arc_counter, arc_get_core_freq());
- /* sets up the periodic event timer */
- arc_local_timer_setup();
+ arc_clockevent_setup();
}
--
2.5.0
