clocksource/metag: 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 <rcochran@linutronix.de>
Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-metag@vger.kernel.org
Cc: rt@linutronix.de
Link: http://lkml.kernel.org/r/20160713153336.215137642@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>

2 files changed, 7 insertions, 27 deletions

diff --git a/drivers/clocksource/metag_generic.c b/drivers/clocksource/metag_generic.c
index bcd5c0d602a0..a80ab3e446b7 100644
--- a/drivers/clocksource/metag_generic.c
+++ b/drivers/clocksource/metag_generic.c
@@ -90,7 +90,7 @@ unsigned long long sched_clock(void)
         return ticks << HARDWARE_TO_NS_SHIFT;
 }
 
-static void arch_timer_setup(unsigned int cpu)
+static int arch_timer_starting_cpu(unsigned int cpu)
 {
         unsigned int txdivtime;
         struct clock_event_device *clk = &per_cpu(local_clockevent, cpu);
@@ -132,27 +132,9 @@ static void arch_timer_setup(unsigned int cpu)
                 val = core_reg_read(TXUCT_ID, TXTIMER_REGNUM, thread0);
                 __core_reg_set(TXTIMER, val);
         }
+        return 0;
 }
 
-static int arch_timer_cpu_notify(struct notifier_block *self,
-                                           unsigned long action, void *hcpu)
-{
-        int cpu = (long)hcpu;
-
-        switch (action) {
-        case CPU_STARTING:
-        case CPU_STARTING_FROZEN:
-                arch_timer_setup(cpu);
-                break;
-        }
-
-        return NOTIFY_OK;
-}
-
-static struct notifier_block arch_timer_cpu_nb = {
-        .notifier_call = arch_timer_cpu_notify,
-};
-
 int __init metag_generic_timer_init(void)
 {
         /*
@@ -170,11 +152,8 @@ int __init metag_generic_timer_init(void)
 
         setup_irq(tbisig_map(TBID_SIGNUM_TRT), &metag_timer_irq);
 
-        /* Configure timer on boot CPU */
-        arch_timer_setup(smp_processor_id());
-
-        /* Hook cpu boot to configure other CPU's timers */
-        register_cpu_notifier(&arch_timer_cpu_nb);
-
-        return 0;
+        /* Hook cpu boot to configure the CPU's timers */
+        return cpuhp_setup_state(CPUHP_AP_METAG_TIMER_STARTING,
+                                 "AP_METAG_TIMER_STARTING",
+                                 arch_timer_starting_cpu, NULL);
 }
diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
index 81035613a836..afba3b19006c 100644
--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h
@@ -38,6 +38,7 @@ enum cpuhp_state {
         CPUHP_AP_PERF_ARM_STARTING,
         CPUHP_AP_ARM_ARCH_TIMER_STARTING,
         CPUHP_AP_DUMMY_TIMER_STARTING,
+        CPUHP_AP_METAG_TIMER_STARTING,
         CPUHP_AP_KVM_STARTING,
         CPUHP_AP_NOTIFY_STARTING,
         CPUHP_AP_ONLINE,