ARM: mach-shmobile: SMP base support

Add SMP base support for R-Mobile / SH-Mobile processors.

This patch contains all base code to support CONFIG_SMP
regardless of ARCH_SHMOBILE processor type. Both local timer
and CPU hotplug are supported, but no processor specific
code is included.

At this point only the default behavior is in place, so
a single core will always be used even though CONFIG_SMP
is enabled on multicore systems.

The SMP Kconfig entry for arch/arm/Kconfig is excluded from
this patch to simplify merging.

Signed-off-by: Magnus Damm <damm@opensource.se>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>

1 files changed, 73 insertions, 0 deletions

diff --git a/arch/arm/mach-shmobile/platsmp.c b/arch/arm/mach-shmobile/platsmp.c
new file mode 100644
index 0000000..b41f5d0
--- /dev/null
+++ b/arch/arm/mach-shmobile/platsmp.c
@@ -0,0 +1,73 @@
+/*
+ * SMP support for R-Mobile / SH-Mobile
+ *
+ * Copyright (C) 2010  Magnus Damm
+ *
+ * Based on vexpress, Copyright (C) 2002 ARM Ltd, All Rights Reserved
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#include <linux/init.h>
+#include <linux/errno.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/smp.h>
+#include <linux/io.h>
+#include <asm/localtimer.h>
+
+static unsigned int __init shmobile_smp_get_core_count(void)
+{
+	return 1;
+}
+
+static void __init shmobile_smp_prepare_cpus(void)
+{
+	/* do nothing for now */
+}
+
+
+void __cpuinit platform_secondary_init(unsigned int cpu)
+{
+	trace_hardirqs_off();
+}
+
+int __cpuinit boot_secondary(unsigned int cpu, struct task_struct *idle)
+{
+	return -ENOSYS;
+}
+
+void __init smp_init_cpus(void)
+{
+	unsigned int ncores = shmobile_smp_get_core_count();
+	unsigned int i;
+
+	for (i = 0; i < ncores; i++)
+		set_cpu_possible(i, true);
+}
+
+void __init smp_prepare_cpus(unsigned int max_cpus)
+{
+	unsigned int ncores = shmobile_smp_get_core_count();
+	unsigned int cpu = smp_processor_id();
+	int i;
+
+	smp_store_cpu_info(cpu);
+
+	if (max_cpus > ncores)
+		max_cpus = ncores;
+
+	for (i = 0; i < max_cpus; i++)
+		set_cpu_present(i, true);
+
+	if (max_cpus > 1) {
+		shmobile_smp_prepare_cpus();
+
+		/*
+		 * Enable the local timer or broadcast device for the
+		 * boot CPU, but only if we have more than one CPU.
+		 */
+		percpu_timer_setup();
+	}
+}