[patch 38/66] clocksource/arm_global_timer: Convert to hotplug state machine.
From: anna-maria@linutronix.de (Anna-Maria Gleixner)
Date: 2016-07-11 12:40:34
Also in:
lkml
From: Richard Cochran <redacted> Install the callbacks via the state machine and let the core invoke the callbacks on the already online CPUs. Signed-off-by: Richard Cochran <redacted> Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Srinivas Kandagatla <redacted> Cc: Maxime Coquelin <redacted> Cc: Patrice Chotard <redacted> Cc: Daniel Lezcano <redacted> Cc: linux-arm-kernel at lists.infradead.org Cc: kernel at stlinux.com Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de> --- drivers/clocksource/arm_global_timer.c | 41 ++++++++------------------------- include/linux/cpuhotplug.h | 1 2 files changed, 11 insertions(+), 31 deletions(-)
--- a/drivers/clocksource/arm_global_timer.c
+++ b/drivers/clocksource/arm_global_timer.c@@ -165,9 +165,9 @@ static irqreturn_t gt_clockevent_interru return IRQ_HANDLED; } -static int gt_clockevents_init(struct clock_event_device *clk) +static int gt_starting_cpu(unsigned int cpu) { - int cpu = smp_processor_id(); + struct clock_event_device *clk = this_cpu_ptr(gt_evt); clk->name = "arm_global_timer"; clk->features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT |
@@ -186,10 +186,13 @@ static int gt_clockevents_init(struct cl return 0; } -static void gt_clockevents_stop(struct clock_event_device *clk) +static int gt_dying_cpu(unsigned int cpu) { + struct clock_event_device *clk = this_cpu_ptr(gt_evt); + gt_clockevent_shutdown(clk); disable_percpu_irq(clk->irq); + return 0; } static cycle_t gt_clocksource_read(struct clocksource *cs)
@@ -252,24 +255,6 @@ static void __init gt_clocksource_init(v clocksource_register_hz(>_clocksource, gt_clk_rate); } -static int gt_cpu_notify(struct notifier_block *self, unsigned long action, - void *hcpu) -{ - switch (action & ~CPU_TASKS_FROZEN) { - case CPU_STARTING: - gt_clockevents_init(this_cpu_ptr(gt_evt)); - break; - case CPU_DYING: - gt_clockevents_stop(this_cpu_ptr(gt_evt)); - break; - } - - return NOTIFY_OK; -} -static struct notifier_block gt_cpu_nb = { - .notifier_call = gt_cpu_notify, -}; - static void __init global_timer_of_register(struct device_node *np) { struct clk *gt_clk;
@@ -325,21 +310,15 @@ static void __init global_timer_of_regis goto out_free; } - err = register_cpu_notifier(>_cpu_nb); - if (err) { - pr_warn("global-timer: unable to register cpu notifier.\n"); - goto out_irq; - } - - /* Immediately configure the timer on the boot CPU */ + /* Register and immediately configure the timer on the boot CPU */ gt_clocksource_init(); - gt_clockevents_init(this_cpu_ptr(gt_evt)); + cpuhp_setup_state(CPUHP_AP_ARM_GLOBAL_TIMER_STARTING, + "AP_ARM_GLOBAL_TIMER_STARTING", gt_starting_cpu, + gt_dying_cpu); gt_delay_timer_init(); return; -out_irq: - free_percpu_irq(gt_ppi, gt_evt); out_free: free_percpu(gt_evt); out_clk: --- a/include/linux/cpuhotplug.h +++ b/include/linux/cpuhotplug.h
@@ -38,6 +38,7 @@ enum cpuhp_state { CPUHP_AP_ARM_VFP_STARTING, CPUHP_AP_PERF_ARM_STARTING, CPUHP_AP_ARM_ARCH_TIMER_STARTING, + CPUHP_AP_ARM_GLOBAL_TIMER_STARTING, CPUHP_AP_KVM_STARTING, CPUHP_AP_NOTIFY_STARTING, CPUHP_AP_ONLINE,