From 04766fba9325c5603c9ee09f728d99f4ce577e94 Mon Sep 17 00:00:00 2001
From: Magnus Damm <damm@opensource.se>
Date: Wed, 28 Dec 2011 16:53:16 +0900
Subject: [PATCH] --- yaml --- r: 283644 b: refs/heads/master c:
 1229835ccb6d7ea2b36230121205be95c88eca88 h: refs/heads/master v: v3

---
 [refs]                                 |  2 +-
 trunk/arch/arm/mach-shmobile/hotplug.c | 31 +++++++++++++++++++++++++-
 2 files changed, 31 insertions(+), 2 deletions(-)

diff --git a/[refs] b/[refs]
index 3ddbccc93247..a60190872474 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 8b306796995609c281f6d32b3cbaa814551ad5ac
+refs/heads/master: 1229835ccb6d7ea2b36230121205be95c88eca88
diff --git a/trunk/arch/arm/mach-shmobile/hotplug.c b/trunk/arch/arm/mach-shmobile/hotplug.c
index aee3a1088a5a..828d22f3af57 100644
--- a/trunk/arch/arm/mach-shmobile/hotplug.c
+++ b/trunk/arch/arm/mach-shmobile/hotplug.c
@@ -12,15 +12,43 @@
 #include <linux/kernel.h>
 #include <linux/errno.h>
 #include <linux/smp.h>
+#include <linux/cpumask.h>
+#include <linux/delay.h>
 #include <mach/common.h>
+#include <asm/cacheflush.h>
+
+static cpumask_t dead_cpus;
 
 int platform_cpu_kill(unsigned int cpu)
 {
-	return shmobile_platform_cpu_kill(cpu);
+	int k;
+
+	/* this function is running on another CPU than the offline target,
+	 * here we need wait for shutdown code in platform_cpu_die() to
+	 * finish before asking SoC-specific code to power off the CPU core.
+	 */
+	for (k = 0; k < 1000; k++) {
+		if (cpumask_test_cpu(cpu, &dead_cpus))
+			return shmobile_platform_cpu_kill(cpu);
+
+		mdelay(1);
+	}
+
+	return 0;
 }
 
 void platform_cpu_die(unsigned int cpu)
 {
+	/* hardware shutdown code running on the CPU that is being offlined */
+	flush_cache_all();
+	dsb();
+
+	/* notify platform_cpu_kill() that hardware shutdown is finished */
+	cpumask_set_cpu(cpu, &dead_cpus);
+
+	/* wait for SoC code in platform_cpu_kill() to shut off CPU core
+	 * power. CPU bring up starts from the reset vector.
+	 */
 	while (1) {
 		/*
 		 * here's the WFI
@@ -34,6 +62,7 @@ void platform_cpu_die(unsigned int cpu)
 
 int platform_cpu_disable(unsigned int cpu)
 {
+	cpumask_clear_cpu(cpu, &dead_cpus);
 	/*
 	 * we don't allow CPU 0 to be shutdown (it is still too special
 	 * e.g. clock tick interrupts)