ARM: highbank: Add cpu hotplug support

This adds cpu hotplug for highbank. On highbank, a core is always reset and
boots up the same path as a cold boot.

Signed-off-by: Martin Bogomolni <martin@calxeda.com>
Signed-off-by: Rob Herring <rob.herring@calxeda.com>
Reviewed-by: Jamie Iles <jamie@jamieiles.com>
Reviewed-by: Shawn Guo <shawn.guo@linaro.org>

arch/arm/mach-highbank/Makefile

@@ -2,3 +2,4 @@ obj-y					:= clock.o highbank.o system.o
 obj-$(CONFIG_DEBUG_HIGHBANK_UART)	+= lluart.o
 obj-$(CONFIG_SMP)			+= platsmp.o
 obj-$(CONFIG_LOCAL_TIMERS)		+= localtimer.o
+obj-$(CONFIG_HOTPLUG_CPU)		+= hotplug.o

arch/arm/mach-highbank/hotplug.c

@@ -0,0 +1,56 @@
+/*
+ * Copyright 2011 Calxeda, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/smp.h>
+
+#include <asm/smp_scu.h>
+#include <asm/cacheflush.h>
+
+#include "core.h"
+
+extern void secondary_startup(void);
+
+int platform_cpu_kill(unsigned int cpu)
+{
+	return 1;
+}
+
+/*
+ * platform-specific code to shutdown a CPU
+ *
+ */
+void platform_cpu_die(unsigned int cpu)
+{
+	flush_cache_all();
+
+	highbank_set_cpu_jump(cpu, secondary_startup);
+	scu_power_mode(scu_base_addr, SCU_PM_POWEROFF);
+
+	cpu_do_idle();
+
+	/* We should never return from idle */
+	panic("highbank: cpu %d unexpectedly exit from shutdown\n", cpu);
+}
+
+int platform_cpu_disable(unsigned int cpu)
+{
+	/*
+	 * CPU0 should not be shut down via hotplug.  cpu_idle can WFI
+	 * or a proper shutdown or hibernate should be used.
+	 */
+	return cpu == 0 ? -EPERM : 0;
+}