[patch 37/66] clocksource/arm_arch_timer: Convert to hotplug state machine.
From: Anna-Maria Gleixner <anna-maria@linutronix.de>
Date: 2016-07-11 12:41:30
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: Anna-Maria Gleixner <anna-maria@linutronix.de> Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Daniel Lezcano <redacted> --- drivers/clocksource/arm_arch_timer.c | 54 ++++++++++++++++------------------- include/linux/cpuhotplug.h | 1 2 files changed, 27 insertions(+), 28 deletions(-)
--- a/drivers/clocksource/arm_arch_timer.c
+++ b/drivers/clocksource/arm_arch_timer.c@@ -362,8 +362,10 @@ static bool arch_timer_has_nonsecure_ppi arch_timer_ppi[PHYS_NONSECURE_PPI]); } -static int arch_timer_setup(struct clock_event_device *clk) +static int arch_timer_starting_cpu(unsigned int cpu) { + struct clock_event_device *clk = this_cpu_ptr(arch_timer_evt); + __arch_timer_setup(ARCH_CP15_TIMER, clk); enable_percpu_irq(arch_timer_ppi[arch_timer_uses_ppi], 0);
@@ -519,29 +521,14 @@ static void arch_timer_stop(struct clock clk->set_state_shutdown(clk); } -static int arch_timer_cpu_notify(struct notifier_block *self, - unsigned long action, void *hcpu) +static int arch_timer_dying_cpu(unsigned int cpu) { - /* - * Grab cpu pointer in each case to avoid spurious - * preemptible warnings - */ - switch (action & ~CPU_TASKS_FROZEN) { - case CPU_STARTING: - arch_timer_setup(this_cpu_ptr(arch_timer_evt)); - break; - case CPU_DYING: - arch_timer_stop(this_cpu_ptr(arch_timer_evt)); - break; - } + struct clock_event_device *clk = this_cpu_ptr(arch_timer_evt); - return NOTIFY_OK; + arch_timer_stop(clk); + return 0; } -static struct notifier_block arch_timer_cpu_nb = { - .notifier_call = arch_timer_cpu_notify, -}; - #ifdef CONFIG_CPU_PM static unsigned int saved_cntkctl; static int arch_timer_cpu_pm_notify(struct notifier_block *self,
@@ -562,11 +549,21 @@ static int __init arch_timer_cpu_pm_init { return cpu_pm_register_notifier(&arch_timer_cpu_pm_notifier); } + +static void __init arch_timer_cpu_pm_deinit(void) +{ + WARN_ON(cpu_pm_unregister_notifier(&arch_timer_cpu_pm_notifier)); +} + #else static int __init arch_timer_cpu_pm_init(void) { return 0; } + +static void __init arch_timer_cpu_pm_deinit(void) +{ +} #endif static int __init arch_timer_register(void)
@@ -613,22 +610,23 @@ static int __init arch_timer_register(vo goto out_free; } - err = register_cpu_notifier(&arch_timer_cpu_nb); - if (err) - goto out_free_irq; - err = arch_timer_cpu_pm_init(); if (err) goto out_unreg_notify; - /* Immediately configure the timer on the boot CPU */ - arch_timer_setup(this_cpu_ptr(arch_timer_evt)); + /* Register and immediately configure the timer on the boot CPU */ + err = cpuhp_setup_state(CPUHP_AP_ARM_ARCH_TIMER_STARTING, + "AP_ARM_ARCH_TIMER_STARTING", + arch_timer_starting_cpu, arch_timer_dying_cpu); + if (err) + goto out_unreg_cpupm; return 0; +out_unreg_cpupm: + arch_timer_cpu_pm_deinit(); + out_unreg_notify: - unregister_cpu_notifier(&arch_timer_cpu_nb); -out_free_irq: free_percpu_irq(arch_timer_ppi[arch_timer_uses_ppi], arch_timer_evt); if (arch_timer_has_nonsecure_ppi()) free_percpu_irq(arch_timer_ppi[PHYS_NONSECURE_PPI], --- a/include/linux/cpuhotplug.h +++ b/include/linux/cpuhotplug.h
@@ -37,6 +37,7 @@ enum cpuhp_state { CPUHP_AP_PERF_XTENSA_STARTING, CPUHP_AP_ARM_VFP_STARTING, CPUHP_AP_PERF_ARM_STARTING, + CPUHP_AP_ARM_ARCH_TIMER_STARTING, CPUHP_AP_KVM_STARTING, CPUHP_AP_NOTIFY_STARTING, CPUHP_AP_ONLINE,