ARM: tango: add HOTPLUG_CPU support

[linux-2.6-microblaze.git] / arch / arm / mach-tango / platsmp.c

diff --git a/arch/arm/mach-tango/platsmp.c b/arch/arm/mach-tango/platsmp.c
index a21f55e..8380699 100644 (file)
--- 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);