ARM: tango: add HOTPLUG_CPU support

cpu_die() and cpu_kill() are implemented in firmware.

Signed-off-by: Marc Gonzalez <marc_gonzalez@sigmadesigns.com>
Signed-off-by: Olof Johansson <olof@lixom.net>

1 files changed, 36 insertions, 0 deletions

diff --git a/arch/arm/mach-tango/platsmp.c b/arch/arm/mach-tango/platsmp.c
index a21f55e000d2..8380699d4fa3 100644
--- a/arch/arm/mach-tango/platsmp.c
+++ b/arch/arm/mach-tango/platsmp.c
@@ -1,3 +1,4 @@
+#include <linux/delay.h>
 #include <linux/init.h>
 #include <linux/smp.h>
 #include "smc.h"
@@ -9,8 +10,43 @@ static int tango_boot_secondary(unsigned int cpu, struct task_struct *idle)
 	return 0;
 }
 
+#ifdef CONFIG_HOTPLUG_CPU
+/*
+ * cpu_kill() and cpu_die() run concurrently on different cores.
+ * Firmware will only "kill" a core once it has properly "died".
+ * Try a few times to kill a core before giving up, and sleep
+ * between tries to give that core enough time to die.
+ */
+static int tango_cpu_kill(unsigned int cpu)
+{
+	int i, err;
+
+	for (i = 0; i < 10; ++i) {
+		msleep(10);
+		err = tango_aux_core_kill(cpu);
+		if (!err)
+			return true;
+	}
+
+	return false;
+}
+
+static void tango_cpu_die(unsigned int cpu)
+{
+	while (tango_aux_core_die(cpu) < 0)
+		cpu_relax();
+
+	panic("cpu %d failed to die\n", cpu);
+}
+#else
+#define tango_cpu_kill	NULL
+#define tango_cpu_die	NULL
+#endif
+
 static const struct smp_operations tango_smp_ops __initconst = {
 	.smp_boot_secondary	= tango_boot_secondary,
+	.cpu_kill		= tango_cpu_kill,
+	.cpu_die		= tango_cpu_die,
 };
 
 CPU_METHOD_OF_DECLARE(tango4_smp, "sigma,tango4-smp", &tango_smp_ops);