From d11b3a60fcc8c6e44dd370f1cf2738eb5bec7353 Mon Sep 17 00:00:00 2001 From: Richard Cochran Date: Wed, 13 Jul 2016 17:17:05 +0000 Subject: [PATCH] clocksource/exynos_mct: Convert to hotplug state machine Install the callbacks via the state machine and let the core invoke the callbacks on the already online CPUs. Signed-off-by: Richard Cochran Signed-off-by: Anna-Maria Gleixner Reviewed-by: Sebastian Andrzej Siewior Cc: Daniel Lezcano Cc: Krzysztof Kozlowski Cc: Kukjin Kim Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-samsung-soc@vger.kernel.org Cc: rt@linutronix.de Link: http://lkml.kernel.org/r/20160713153338.147940411@linutronix.de Signed-off-by: Ingo Molnar --- drivers/clocksource/exynos_mct.c | 46 +++++++++----------------------- include/linux/cpuhotplug.h | 1 + 2 files changed, 13 insertions(+), 34 deletions(-) diff --git a/drivers/clocksource/exynos_mct.c b/drivers/clocksource/exynos_mct.c index 0d18dd4b3bd2..41840d02c331 100644 --- a/drivers/clocksource/exynos_mct.c +++ b/drivers/clocksource/exynos_mct.c @@ -443,10 +443,11 @@ static irqreturn_t exynos4_mct_tick_isr(int irq, void *dev_id) 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(struct mct_clock_event_device *mevt) 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(struct mct_clock_event_device *mevt) } 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_resources(struct device_node *np, void __iomem * } } - 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: diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h index d24b0fc2f88d..7ad8a7e7806d 100644 --- a/include/linux/cpuhotplug.h +++ b/include/linux/cpuhotplug.h @@ -49,6 +49,7 @@ 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, -- 2.20.1