ARM/shmobile: Convert to hotplug state machine

Install the callbacks via the state machine so the old notifier based
cpuhotplug infrastructure can be removed.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: linux-sh@vger.kernel.org
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Magnus Damm <magnus.damm@gmail.com>
Cc: Simon Horman <horms@verge.net.au>
Cc: rt@linutronix.de
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/20160906170457.32393-3-bigeasy@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

arch/arm/mach-shmobile/platsmp-scu.c

@@ -21,26 +21,14 @@
 static phys_addr_t shmobile_scu_base_phys;
 static void __iomem *shmobile_scu_base;
 
-static int shmobile_smp_scu_notifier_call(struct notifier_block *nfb,
-					  unsigned long action, void *hcpu)
+static int shmobile_scu_cpu_prepare(unsigned int cpu)
 {
-	unsigned int cpu = (long)hcpu;
-
-	switch (action) {
-	case CPU_UP_PREPARE:
-		/* For this particular CPU register SCU SMP boot vector */
-		shmobile_smp_hook(cpu, virt_to_phys(shmobile_boot_scu),
-				  shmobile_scu_base_phys);
-		break;
-	};
-
-	return NOTIFY_OK;
+	/* For this particular CPU register SCU SMP boot vector */
+	shmobile_smp_hook(cpu, virt_to_phys(shmobile_boot_scu),
+			  shmobile_scu_base_phys);
+	return 0;
 }
 
-static struct notifier_block shmobile_smp_scu_notifier = {
-	.notifier_call = shmobile_smp_scu_notifier_call,
-};
-
 void __init shmobile_smp_scu_prepare_cpus(phys_addr_t scu_base_phys,
 					  unsigned int max_cpus)
 {
@@ -54,7 +42,9 @@ void __init shmobile_smp_scu_prepare_cpus(phys_addr_t scu_base_phys,
 	scu_power_mode(shmobile_scu_base, SCU_PM_NORMAL);
 
 	/* Use CPU notifier for reset vector control */
-	register_cpu_notifier(&shmobile_smp_scu_notifier);
+	cpuhp_setup_state_nocalls(CPUHP_ARM_SHMOBILE_SCU_PREPARE,
+				  "arm/shmobile-scu:prepare",
+				  shmobile_scu_cpu_prepare, NULL);
 }
 
 #ifdef CONFIG_HOTPLUG_CPU

include/linux/cpuhotplug.h

@@ -35,6 +35,7 @@ enum cpuhp_state {
 	CPUHP_POWERPC_PMAC_PREPARE,
 	CPUHP_POWERPC_MMU_CTX_PREPARE,
 	CPUHP_NOTIFY_PREPARE,
+	CPUHP_ARM_SHMOBILE_SCU_PREPARE,
 	CPUHP_TIMERS_DEAD,
 	CPUHP_BRINGUP_CPU,
 	CPUHP_AP_IDLE_DEAD,