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

[Anna-Maria Gleixner]

From: Richard Cochran <rcoch...@linutronix.de>

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

Signed-off-by: Richard Cochran <rcoch...@linutronix.de>
Reviewed-by: Sebastian Andrzej Siewior <bige...@linutronix.de>
Cc: Daniel Lezcano <daniel.lezc...@linaro.org>
Cc: Linus Torvalds <torva...@linux-foundation.org>
Cc: Peter Zijlstra <pet...@infradead.org>
Cc: Thomas Gleixner <t...@linutronix.de>
Signed-off-by: Anna-Maria Gleixner <anna-ma...@linutronix.de>
---
 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