arm/boot: Allow boards to modify the FDT blob

Add a callback hook in arm_boot_info to allow board models to
modify the device tree blob if they need to. (The major expected
use case is to add virtio-mmio nodes for virtio-mmio transports
that exist in QEMU but not in the hardware.)

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 1373977512-28932-7-git-send-email-peter.maydell@linaro.org

diff --git a/hw/arm/boot.c b/hw/arm/boot.c
index 1780316..9fbe5d2 100644 (file)
--- a/hw/arm/boot.c
+++ b/hw/arm/boot.c
@@ -294,6 +294,11 @@ static int load_dtb(hwaddr addr, const struct arm_boot_info *binfo)
             goto fail;
         }
     }
+
+    if (binfo->modify_dtb) {
+        binfo->modify_dtb(binfo, fdt);
+    }
+
     qemu_devtree_dumpdtb(fdt, size);
 
     cpu_physical_memory_write(addr, fdt, size);

diff --git a/include/hw/arm/arm.h b/include/hw/arm/arm.h
index 7b2b02d..bae87c6 100644 (file)
--- a/include/hw/arm/arm.h
+++ b/include/hw/arm/arm.h
@@ -55,6 +55,10 @@ struct arm_boot_info {
                                  const struct arm_boot_info *info);
     void (*secondary_cpu_reset_hook)(ARMCPU *cpu,
                                      const struct arm_boot_info *info);
+    /* if a board needs to be able to modify a device tree provided by
+     * the user it should implement this hook.
+     */
+    void (*modify_dtb)(const struct arm_boot_info *info, void *fdt);
     /* Used internally by arm_boot.c */
     int is_linux;
     hwaddr initrd_start;