[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>
---
v2: comment style, call exit(1) on load_dtb() failure

 hw/arm/boot.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/hw/arm/boot.c b/hw/arm/boot.c
index e32f2f415885..a32ff28d9be1 100644
--- a/hw/arm/boot.c
+++ b/hw/arm/boot.c
@@ -459,6 +459,17 @@ void arm_load_kernel(ARMCPU *cpu, struct arm_boot_info *info)
 
     /* Load the kernel.  */
     if (!info->kernel_filename) {
+
+        if (have_dtb(info)) {
+            /* 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 (load_dtb(info->loader_start, info)) {
+                exit(1);
+            }
+        }
+
         /* 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