From a7b3d5a715f489ee542e59d722281c9f16da50dc Mon Sep 17 00:00:00 2001
From: Jisheng Zhang <jszhang@marvell.com>
Date: Mon, 14 Sep 2015 14:47:45 +0800
Subject: [PATCH] arm: berlin: add CPU hotplug support

Add cpu hotplug support for berlin SoCs such as BG2 and BG2Q. These SoC
don't support power off cpu independently, but we also want cpu hotplug
support in these SoCs. We achieve this goal by putting the dying CPU in
WFI state after the coherency is disabled, then asserting the dying CPU
reset bit to put the CPU in reset state.

Signed-off-by: Jisheng Zhang <jszhang@marvell.com>
Signed-off-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
---
 arch/arm/mach-berlin/platsmp.c | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/arch/arm/mach-berlin/platsmp.c b/arch/arm/mach-berlin/platsmp.c
index 64cb1ab182c4..405cd37e4fba 100644
--- a/arch/arm/mach-berlin/platsmp.c
+++ b/arch/arm/mach-berlin/platsmp.c
@@ -14,6 +14,7 @@
 #include <linux/of_address.h>
 
 #include <asm/cacheflush.h>
+#include <asm/cp15.h>
 #include <asm/smp_plat.h>
 #include <asm/smp_scu.h>
 
@@ -98,8 +99,32 @@ static void __init berlin_smp_prepare_cpus(unsigned int max_cpus)
 	iounmap(scu_base);
 }
 
+#ifdef CONFIG_HOTPLUG_CPU
+static void berlin_cpu_die(unsigned int cpu)
+{
+	v7_exit_coherency_flush(louis);
+	while (1)
+		cpu_do_idle();
+}
+
+static int berlin_cpu_kill(unsigned int cpu)
+{
+	u32 val;
+
+	val = readl(cpu_ctrl + CPU_RESET_NON_SC);
+	val &= ~BIT(cpu_logical_map(cpu));
+	writel(val, cpu_ctrl + CPU_RESET_NON_SC);
+
+	return 1;
+}
+#endif
+
 static struct smp_operations berlin_smp_ops __initdata = {
 	.smp_prepare_cpus	= berlin_smp_prepare_cpus,
 	.smp_boot_secondary	= berlin_boot_secondary,
+#ifdef CONFIG_HOTPLUG_CPU
+	.cpu_die		= berlin_cpu_die,
+	.cpu_kill		= berlin_cpu_kill,
+#endif
 };
 CPU_METHOD_OF_DECLARE(berlin_smp, "marvell,berlin-smp", &berlin_smp_ops);