[patch V2 42/67] clocksource/mips-gic: Convert to hotplug state machine

From: Anna-Maria Gleixner
Date: Wed Jul 13 2016 - 13:22:12 EST


From: Richard Cochran <rcochran@xxxxxxxxxxxxx>

Install the callbacks via the state machine and let the core invoke
the callbacks on the already online CPUs.

Signed-off-by: Richard Cochran <rcochran@xxxxxxxxxxxxx>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
Cc: Daniel Lezcano <daniel.lezcano@xxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Anna-Maria Gleixner <anna-maria@xxxxxxxxxxxxx>
---
drivers/clocksource/mips-gic-timer.c | 38 ++++++++++++------------------------
include/linux/cpuhotplug.h | 1 +
2 files changed, 14 insertions(+), 25 deletions(-)

diff --git a/drivers/clocksource/mips-gic-timer.c b/drivers/clocksource/mips-gic-timer.c
index 1572c7a..d91e872 100644
--- a/drivers/clocksource/mips-gic-timer.c
+++ b/drivers/clocksource/mips-gic-timer.c
@@ -49,10 +49,9 @@ struct irqaction gic_compare_irqaction = {
.name = "timer",
};

-static void gic_clockevent_cpu_init(struct clock_event_device *cd)
+static void gic_clockevent_cpu_init(unsigned int cpu,
+ struct clock_event_device *cd)
{
- unsigned int cpu = smp_processor_id();
-
cd->name = "MIPS GIC";
cd->features = CLOCK_EVT_FEAT_ONESHOT |
CLOCK_EVT_FEAT_C3STOP;
@@ -79,19 +78,10 @@ static void gic_update_frequency(void *data)
clockevents_update_freq(this_cpu_ptr(&gic_clockevent_device), rate);
}

-static int gic_cpu_notifier(struct notifier_block *nb, unsigned long action,
- void *data)
+static int gic_starting_cpu(unsigned int cpu)
{
- switch (action & ~CPU_TASKS_FROZEN) {
- case CPU_STARTING:
- gic_clockevent_cpu_init(this_cpu_ptr(&gic_clockevent_device));
- break;
- case CPU_DYING:
- gic_clockevent_cpu_exit(this_cpu_ptr(&gic_clockevent_device));
- break;
- }
-
- return NOTIFY_OK;
+ gic_clockevent_cpu_init(cpu, this_cpu_ptr(&gic_clockevent_device));
+ return 0;
}

static int gic_clk_notifier(struct notifier_block *nb, unsigned long action,
@@ -105,10 +95,11 @@ static int gic_clk_notifier(struct notifier_block *nb, unsigned long action,
return NOTIFY_OK;
}

-
-static struct notifier_block gic_cpu_nb = {
- .notifier_call = gic_cpu_notifier,
-};
+static int gic_dying_cpu(unsigned int cpu)
+{
+ gic_clockevent_cpu_exit(this_cpu_ptr(&gic_clockevent_device));
+ return 0;
+}

static struct notifier_block gic_clk_nb = {
.notifier_call = gic_clk_notifier,
@@ -125,12 +116,9 @@ static int gic_clockevent_init(void)
if (ret < 0)
return ret;

- ret = register_cpu_notifier(&gic_cpu_nb);
- if (ret < 0)
- pr_warn("GIC: Unable to register CPU notifier\n");
-
- gic_clockevent_cpu_init(this_cpu_ptr(&gic_clockevent_device));
-
+ cpuhp_setup_state(CPUHP_AP_MIPS_GIC_TIMER_STARTING,
+ "AP_MIPS_GIC_TIMER_STARTING", gic_starting_cpu,
+ gic_dying_cpu);
return 0;
}

diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
index 5121ec1..c052b04 100644
--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h
@@ -41,6 +41,7 @@ enum cpuhp_state {
CPUHP_AP_DUMMY_TIMER_STARTING,
CPUHP_AP_METAG_TIMER_STARTING,
CPUHP_AP_QCOM_TIMER_STARTING,
+ CPUHP_AP_MIPS_GIC_TIMER_STARTING,
CPUHP_AP_KVM_STARTING,
CPUHP_AP_NOTIFY_STARTING,
CPUHP_AP_ONLINE,
--
2.8.1