[Qemu-devel] [PATCH] hw/arm/boot: load device tree to base of DRAM if no -kernel option was passed

[Ard Biesheuvel <ard.biesheuvel@linaro.org>]

If we are running the 'virt' machine, we may have a device tree blob but no
kernel to supply it to if no -kernel option was passed. In that case, copy it
to the base of DRAM where it can be picked up by a bootloader executing from
NOR flash.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 hw/arm/boot.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/hw/arm/boot.c b/hw/arm/boot.c
index 3d1f4a255b48..ff6a727613aa 100644
--- a/hw/arm/boot.c
+++ b/hw/arm/boot.c
@@ -455,6 +455,14 @@ void arm_load_kernel(ARMCPU *cpu, struct arm_boot_info *info)
 
     /* Load the kernel.  */
     if (!info->kernel_filename) {
+        /*
+         * If we have a device tree blob, but no kernel to supply it to, copy it
+         * to the base of DRAM for a bootloader executing from NOR flash to
+         * pick up.
+         */
+        if (have_dtb(info))
+            load_dtb(info->loader_start, info);
+
         /* If no kernel specified, do nothing; we will start from address 0
          * (typically a boot ROM image) in the same way as hardware.
          */
-- 
1.8.3.2