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Subject[patch 51/66] arm: twd: Convert to hotplug state machine
From: Richard Cochran <rcochran@linutronix.de>

Install the callbacks via the state machine. The callbacks won't be invoked on
already online CPUs.

Signed-off-by: Richard Cochran <rcochran@linutronix.de>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Cc: linux-arm-kernel@lists.infradead.org
Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de>
---
arch/arm/kernel/smp_twd.c | 31 +++++++++++--------------------
include/linux/cpuhotplug.h | 1 +
2 files changed, 12 insertions(+), 20 deletions(-)

--- a/arch/arm/kernel/smp_twd.c
+++ b/arch/arm/kernel/smp_twd.c
@@ -310,24 +310,17 @@ static void twd_timer_setup(void)
enable_percpu_irq(clk->irq, 0);
}

-static int twd_timer_cpu_notify(struct notifier_block *self,
- unsigned long action, void *hcpu)
+static int twd_timer_starting_cpu(unsigned int cpu)
{
- switch (action & ~CPU_TASKS_FROZEN) {
- case CPU_STARTING:
- twd_timer_setup();
- break;
- case CPU_DYING:
- twd_timer_stop();
- break;
- }
-
- return NOTIFY_OK;
+ twd_timer_setup();
+ return 0;
}

-static struct notifier_block twd_timer_cpu_nb = {
- .notifier_call = twd_timer_cpu_notify,
-};
+static int twd_timer_dying_cpu(unsigned int cpu)
+{
+ twd_timer_stop();
+ return 0;
+}

static int __init twd_local_timer_common_register(struct device_node *np)
{
@@ -345,9 +338,9 @@ static int __init twd_local_timer_common
goto out_free;
}

- err = register_cpu_notifier(&twd_timer_cpu_nb);
- if (err)
- goto out_irq;
+ cpuhp_setup_state_nocalls(CPUHP_AP_ARM_TWD_STARTING,
+ "AP_ARM_TWD_STARTING",
+ twd_timer_starting_cpu, twd_timer_dying_cpu);

twd_get_clock(np);
if (!of_property_read_bool(np, "always-on"))
@@ -365,8 +358,6 @@ static int __init twd_local_timer_common

return 0;

-out_irq:
- free_percpu_irq(twd_ppi, twd_evt);
out_free:
iounmap(twd_base);
twd_base = NULL;
--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h
@@ -42,6 +42,7 @@ enum cpuhp_state {
CPUHP_AP_ARM_ARCH_TIMER_STARTING,
CPUHP_AP_ARM_GLOBAL_TIMER_STARTING,
CPUHP_AP_DUMMY_TIMER_STARTING,
+ CPUHP_AP_ARM_TWD_STARTING,
CPUHP_AP_EXYNOS4_MCT_TIMER_STARTING,
CPUHP_AP_METAG_TIMER_STARTING,
CPUHP_AP_QCOM_TIMER_STARTING,

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