MIPS/Loongson-3: Convert oprofile 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>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Robert Richter <rric@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mips@linux-mips.org
Cc: oprofile-list@lists.sf.net
Cc: rt@linutronix.de
Link: http://lkml.kernel.org/r/20160713153337.054827168@linutronix.deSigned-off-by: Ingo Molnar <mingo@kernel.org>

arch/mips/oprofile/op_model_loongson3.c

@@ -168,33 +168,26 @@ static int loongson3_perfcount_handler(void)
 	return handled;
 }
 
-static int loongson3_cpu_callback(struct notifier_block *nfb,
-	unsigned long action, void *hcpu)
+static int loongson3_starting_cpu(unsigned int cpu)
 {
-	switch (action) {
-	case CPU_STARTING:
-	case CPU_STARTING_FROZEN:
 	write_c0_perflo1(reg.control1);
 	write_c0_perflo2(reg.control2);
-		break;
-	case CPU_DYING:
-	case CPU_DYING_FROZEN:
+	return 0;
+}
+
+static int loongson3_dying_cpu(unsigned int cpu)
+{
 	write_c0_perflo1(0xc0000000);
 	write_c0_perflo2(0x40000000);
-		break;
-	}
-
-	return NOTIFY_OK;
+	return 0;
 }
 
-static struct notifier_block loongson3_notifier_block = {
-	.notifier_call = loongson3_cpu_callback
-};
-
 static int __init loongson3_init(void)
 {
 	on_each_cpu(reset_counters, NULL, 1);
-	register_hotcpu_notifier(&loongson3_notifier_block);
+	cpuhp_setup_state_nocalls(CPUHP_AP_MIPS_OP_LOONGSON3_STARTING,
+				  "AP_MIPS_OP_LOONGSON3_STARTING",
+				  loongson3_starting_cpu, loongson3_dying_cpu);
 	save_perf_irq = perf_irq;
 	perf_irq = loongson3_perfcount_handler;
 
@@ -204,7 +197,7 @@ static int __init loongson3_init(void)
 static void loongson3_exit(void)
 {
 	on_each_cpu(reset_counters, NULL, 1);
-	unregister_hotcpu_notifier(&loongson3_notifier_block);
+	cpuhp_remove_state_nocalls(CPUHP_AP_MIPS_OP_LOONGSON3_STARTING);
 	perf_irq = save_perf_irq;
 }
 

include/linux/cpuhotplug.h

@@ -35,6 +35,7 @@ enum cpuhp_state {
 	CPUHP_AP_PERF_X86_CSTATE_STARTING,
 	CPUHP_AP_PERF_XTENSA_STARTING,
 	CPUHP_AP_PERF_METAG_STARTING,
+	CPUHP_AP_MIPS_OP_LOONGSON3_STARTING,
 	CPUHP_AP_ARM_VFP_STARTING,
 	CPUHP_AP_PERF_ARM_STARTING,
 	CPUHP_AP_ARM_L2X0_STARTING,