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Subject[patch V2 03/67] irqchip/gic: Convert to hotplug state machine
From: Richard Cochran <rcochran@linutronix.de>

More or less straightforward, although this driver sports some very
interesting SMP setup code. Regarding the callback ordering, this
deleted comment is interesting:

... the GIC needs to be up before the ARM generic timers.

That comment is half baken as the same requirement is true for perf.

Signed-off-by: Richard Cochran <rcochran@linutronix.de>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de>
---
drivers/irqchip/irq-gic.c | 23 ++++++-----------------
include/linux/cpuhotplug.h | 1 +
2 files changed, 7 insertions(+), 17 deletions(-)

diff --git a/drivers/irqchip/irq-gic.c b/drivers/irqchip/irq-gic.c
index fbc4ae2..606f114 100644
--- a/drivers/irqchip/irq-gic.c
+++ b/drivers/irqchip/irq-gic.c
@@ -984,25 +984,12 @@ static int gic_irq_domain_translate(struct irq_domain *d,
return -EINVAL;
}

-#ifdef CONFIG_SMP
-static int gic_secondary_init(struct notifier_block *nfb, unsigned long action,
- void *hcpu)
+static int gic_starting_cpu(unsigned int cpu)
{
- if (action == CPU_STARTING || action == CPU_STARTING_FROZEN)
- gic_cpu_init(&gic_data[0]);
- return NOTIFY_OK;
+ gic_cpu_init(&gic_data[0]);
+ return 0;
}

-/*
- * Notifier for enabling the GIC CPU interface. Set an arbitrarily high
- * priority because the GIC needs to be up before the ARM generic timers.
- */
-static struct notifier_block gic_cpu_notifier = {
- .notifier_call = gic_secondary_init,
- .priority = 100,
-};
-#endif
-
static int gic_irq_domain_alloc(struct irq_domain *domain, unsigned int virq,
unsigned int nr_irqs, void *arg)
{
@@ -1148,8 +1135,10 @@ static int __init __gic_init_bases(struct gic_chip_data *gic, int irq_start,
gic_cpu_map[i] = 0xff;
#ifdef CONFIG_SMP
set_smp_cross_call(gic_raise_softirq);
- register_cpu_notifier(&gic_cpu_notifier);
#endif
+ cpuhp_setup_state_nocalls(CPUHP_AP_IRQ_GIC_STARTING,
+ "AP_IRQ_GIC_STARTING",
+ gic_starting_cpu, NULL);
set_handle_irq(gic_handle_irq);
if (static_key_true(&supports_deactivate))
pr_info("GIC: Using split EOI/Deactivate mode\n");
diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
index fe05640..edc8adf 100644
--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h
@@ -9,6 +9,7 @@ enum cpuhp_state {
CPUHP_AP_IDLE_DEAD,
CPUHP_AP_OFFLINE,
CPUHP_AP_SCHED_STARTING,
+ CPUHP_AP_IRQ_GIC_STARTING,
CPUHP_AP_NOTIFY_STARTING,
CPUHP_AP_ONLINE,
CPUHP_TEARDOWN_CPU,
--
2.8.1


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