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Subject[patch V2 63/67] clocksource/exynos_mct: Convert to hotplug state machine
From: Richard Cochran <rcochran@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 <rcochran@linutronix.de>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Kukjin Kim <kgene@kernel.org>
Cc: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Cc: linux-samsung-soc@vger.kernel.org
Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de>
---
drivers/clocksource/exynos_mct.c | 46 ++++++++++-----------------------------
include/linux/cpuhotplug.h | 1
2 files changed, 13 insertions(+), 34 deletions(-)

--- a/drivers/clocksource/exynos_mct.c
+++ b/drivers/clocksource/exynos_mct.c
@@ -443,10 +443,11 @@ static irqreturn_t exynos4_mct_tick_isr(
return IRQ_HANDLED;
}

-static int exynos4_local_timer_setup(struct mct_clock_event_device *mevt)
+static int exynos4_mct_starting_cpu(unsigned int cpu)
{
+ struct mct_clock_event_device *mevt =
+ per_cpu_ptr(&percpu_mct_tick, cpu);
struct clock_event_device *evt = &mevt->evt;
- unsigned int cpu = smp_processor_id();

mevt->base = EXYNOS4_MCT_L_BASE(cpu);
snprintf(mevt->name, sizeof(mevt->name), "mct_tick%d", cpu);
@@ -480,8 +481,10 @@ static int exynos4_local_timer_setup(str
return 0;
}

-static void exynos4_local_timer_stop(struct mct_clock_event_device *mevt)
+static int exynos4_mct_dying_cpu(unsigned int cpu)
{
+ struct mct_clock_event_device *mevt =
+ per_cpu_ptr(&percpu_mct_tick, cpu);
struct clock_event_device *evt = &mevt->evt;

evt->set_state_shutdown(evt);
@@ -491,39 +494,12 @@ static void exynos4_local_timer_stop(str
} else {
disable_percpu_irq(mct_irqs[MCT_L0_IRQ]);
}
+ return 0;
}

-static int exynos4_mct_cpu_notify(struct notifier_block *self,
- unsigned long action, void *hcpu)
-{
- struct mct_clock_event_device *mevt;
-
- /*
- * Grab cpu pointer in each case to avoid spurious
- * preemptible warnings
- */
- switch (action & ~CPU_TASKS_FROZEN) {
- case CPU_STARTING:
- mevt = this_cpu_ptr(&percpu_mct_tick);
- exynos4_local_timer_setup(mevt);
- break;
- case CPU_DYING:
- mevt = this_cpu_ptr(&percpu_mct_tick);
- exynos4_local_timer_stop(mevt);
- break;
- }
-
- return NOTIFY_OK;
-}
-
-static struct notifier_block exynos4_mct_cpu_nb = {
- .notifier_call = exynos4_mct_cpu_notify,
-};
-
static int __init exynos4_timer_resources(struct device_node *np, void __iomem *base)
{
int err, cpu;
- struct mct_clock_event_device *mevt = this_cpu_ptr(&percpu_mct_tick);
struct clk *mct_clk, *tick_clk;

tick_clk = np ? of_clk_get_by_name(np, "fin_pll") :
@@ -570,12 +546,14 @@ static int __init exynos4_timer_resource
}
}

- err = register_cpu_notifier(&exynos4_mct_cpu_nb);
+ /* Install hotplug callbacks which configure the timer on this CPU */
+ err = cpuhp_setup_state(CPUHP_AP_EXYNOS4_MCT_TIMER_STARTING,
+ "AP_EXYNOS4_MCT_TIMER_STARTING",
+ exynos4_mct_starting_cpu,
+ exynos4_mct_dying_cpu);
if (err)
goto out_irq;

- /* Immediately configure the timer on the boot CPU */
- exynos4_local_timer_setup(mevt);
return 0;

out_irq:
--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h
@@ -50,6 +50,7 @@ enum cpuhp_state {
CPUHP_AP_ARM_ARCH_TIMER_STARTING,
CPUHP_AP_ARM_GLOBAL_TIMER_STARTING,
CPUHP_AP_DUMMY_TIMER_STARTING,
+ CPUHP_AP_EXYNOS4_MCT_TIMER_STARTING,
CPUHP_AP_ARM_TWD_STARTING,
CPUHP_AP_METAG_TIMER_STARTING,
CPUHP_AP_QCOM_TIMER_STARTING,

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