ARM: Dummy Virtual Machine platform support

Add support for the smallest, dumbest possible platform, to be
used as a guest for KVM or other hypervisors.

It only mandates a GIC and architected timers. Fits nicely with
a multiplatform zImage. Uses very little silicon area.

Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
[will: fixed up conflicts with GIC move to drivers/irqchip/]
Signed-off-by: Will Deacon <will.deacon@arm.com>

arch/arm/mach-virt/virt.c

@@ -0,0 +1,54 @@
+/*
+ * Dummy Virtual Machine - does what it says on the tin.
+ *
+ * Copyright (C) 2012 ARM Ltd
+ * Authors: Will Deacon <will.deacon@arm.com>,
+ *          Marc Zyngier <marc.zyngier@arm.com>
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that 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/irqchip.h>
+#include <linux/of_irq.h>
+#include <linux/of_platform.h>
+
+#include <asm/arch_timer.h>
+#include <asm/mach/arch.h>
+#include <asm/mach/time.h>
+
+static void __init virt_init(void)
+{
+	of_platform_populate(NULL, of_default_bus_match_table, NULL, NULL);
+}
+
+static void __init virt_timer_init(void)
+{
+	WARN_ON(arch_timer_of_register() != 0);
+	WARN_ON(arch_timer_sched_clock_init() != 0);
+}
+
+static const char *virt_dt_match[] = {
+	"linux,dummy-virt",
+	NULL
+};
+
+static struct sys_timer virt_timer = {
+	.init = virt_timer_init,
+};
+
+DT_MACHINE_START(VIRT, "Dummy Virtual Machine")
+	.init_irq	= irqchip_init,
+	.timer		= &virt_timer,
+	.init_machine	= virt_init,
+	.dt_compat	= virt_dt_match,
+MACHINE_END