[RFC PATCH 1/2] ARM: Dummy Virtual Machine platform support

[Will Deacon]

From: Marc Zyngier <marc.zyngier at arm.com>

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.

Signed-off-by: Marc Zyngier <marc.zyngier at arm.com>
Signed-off-by: Will Deacon <will.deacon at arm.com>
---
 arch/arm/Kconfig            |  2 ++
 arch/arm/Makefile           |  1 +
 arch/arm/mach-virt/Kconfig  |  9 +++++++
 arch/arm/mach-virt/Makefile |  5 ++++
 arch/arm/mach-virt/virt.c   | 65 +++++++++++++++++++++++++++++++++++++++++++++
 5 files changed, 82 insertions(+)
 create mode 100644 arch/arm/mach-virt/Kconfig
 create mode 100644 arch/arm/mach-virt/Makefile
 create mode 100644 arch/arm/mach-virt/virt.c

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 781725e..ba0dca7 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -1126,6 +1126,8 @@ source "arch/arm/mach-versatile/Kconfig"
 source "arch/arm/mach-vexpress/Kconfig"
 source "arch/arm/plat-versatile/Kconfig"
 
+source "arch/arm/mach-virt/Kconfig"
+
 source "arch/arm/mach-w90x900/Kconfig"
 
 # Definitions to make life easier
diff --git a/arch/arm/Makefile b/arch/arm/Makefile
index 5f914fc..e8232ad 100644
--- a/arch/arm/Makefile
+++ b/arch/arm/Makefile
@@ -192,6 +192,7 @@ machine-$(CONFIG_ARCH_SOCFPGA)		+= socfpga
 machine-$(CONFIG_ARCH_SPEAR13XX)	+= spear13xx
 machine-$(CONFIG_ARCH_SPEAR3XX)		+= spear3xx
 machine-$(CONFIG_MACH_SPEAR600)		+= spear6xx
+machine-$(CONFIG_ARCH_VIRT)		+= virt
 machine-$(CONFIG_ARCH_ZYNQ)		+= zynq
 
 # Platform directory name.  This list is sorted alphanumerically
diff --git a/arch/arm/mach-virt/Kconfig b/arch/arm/mach-virt/Kconfig
new file mode 100644
index 0000000..a568a2a
--- /dev/null
+++ b/arch/arm/mach-virt/Kconfig
@@ -0,0 +1,9 @@
+config ARCH_VIRT
+	bool "Dummy Virtual Machine" if ARCH_MULTI_V7
+	select ARCH_WANT_OPTIONAL_GPIOLIB
+	select ARM_GIC
+	select ARM_ARCH_TIMER
+	select HAVE_SMP
+	select CPU_V7
+	select SPARSE_IRQ
+	select USE_OF
diff --git a/arch/arm/mach-virt/Makefile b/arch/arm/mach-virt/Makefile
new file mode 100644
index 0000000..7ddbfa6
--- /dev/null
+++ b/arch/arm/mach-virt/Makefile
@@ -0,0 +1,5 @@
+#
+# Makefile for the linux kernel.
+#
+
+obj-y					:= virt.o
diff --git a/arch/arm/mach-virt/virt.c b/arch/arm/mach-virt/virt.c
new file mode 100644
index 0000000..174b9da
--- /dev/null
+++ b/arch/arm/mach-virt/virt.c
@@ -0,0 +1,65 @@
+/*
+ * Dummy Virtual Machine - does what it says on the tin.
+ *
+ * Copyright (C) 2012 ARM Ltd
+ * Authors: Will Deacon <will.deacon at arm.com>,
+ *          Marc Zyngier <marc.zyngier at 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/of_irq.h>
+#include <linux/of_platform.h>
+
+#include <asm/arch_timer.h>
+#include <asm/hardware/gic.h>
+#include <asm/mach/arch.h>
+#include <asm/mach/time.h>
+
+const static struct of_device_id irq_match[] = {
+	{ .compatible = "arm,cortex-a15-gic", .data = gic_of_init, },
+	{}
+};
+
+static void __init gic_init_irq(void)
+{
+	of_irq_init(irq_match);
+}
+
+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	= gic_init_irq,
+	.handle_irq     = gic_handle_irq,
+	.timer		= &virt_timer,
+	.init_machine	= virt_init,
+	.dt_compat	= virt_dt_match,
+MACHINE_END
-- 
1.8.0