From: Michael Olbrich <m.olbrich@pengutronix.de>
Date: Sat, 10 Sep 2016 17:40:56 +0200
Subject: [PATCH] vexpress: use device tree provided by QEMU if available

Signed-off-by: Michael Olbrich <m.olbrich@pengutronix.de>
---
 arch/arm/boards/vexpress/lowlevel.c | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/arch/arm/boards/vexpress/lowlevel.c b/arch/arm/boards/vexpress/lowlevel.c
index 204d29d8f098..7ed07a1e4134 100644
--- a/arch/arm/boards/vexpress/lowlevel.c
+++ b/arch/arm/boards/vexpress/lowlevel.c
@@ -9,14 +9,27 @@
 #include <asm/barebox-arm-head.h>
 #include <asm/barebox-arm.h>
 #include <asm/system_info.h>
+#include <asm/unaligned.h>
 #include <linux/amba/sp804.h>
 
 void __naked barebox_arm_reset_vector(void)
 {
+	unsigned long membase;
+	void *boarddata;
+
 	arm_cpu_lowlevel_init();
 
 	if (amba_is_arm_sp804(IOMEM(0x10011000)))
-		barebox_arm_entry(0x60000000, SZ_512M, NULL);
+		membase = 0x60000000;
+	else
+		membase = 0x80000000;
+
+	/* QEMU may put a dtb at the bare address */
+	if (IS_ENABLED(CONFIG_OFDEVICE) &&
+			get_unaligned_be32((void*)membase) == FDT_MAGIC)
+		boarddata = (void*)membase;
 	else
-		barebox_arm_entry(0x80000000, SZ_512M, NULL);
+		boarddata = NULL;
+
+	barebox_arm_entry(membase, SZ_512M, boarddata);
 }