[PATCH for-7.2 08/10] device_node.c: enable 'info fdt' to print subnodes

[Daniel Henrique Barboza <danielhb413@gmail.com>]

Printing subnodes of a given node will allow us to show a whole subtree,
which the additional perk of 'info fdt /' being able to print the whole
FDT.

Since we're now printing more than one subnode, change 'fdt_info' to
print the full path of the first node. This small tweak helps
identifying which node or subnode are being displayed.

To demostrate this capability without printing the whole FDT, the
'/cpus/cpu-map' node from the ARM 'virt' machine has a lot of subnodes:

(qemu) info fdt /cpus/cpu-map
/cpus/cpu-map {
    socket0 {
        cluster0 {
            core0 {
                cpu = <0x8001>
            }
        }
    }
}

Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
---
 softmmu/device_tree.c | 18 +++++++++++++++---
 1 file changed, 15 insertions(+), 3 deletions(-)

diff --git a/softmmu/device_tree.c b/softmmu/device_tree.c
index 3a4d09483b..88b6a0c902 100644
--- a/softmmu/device_tree.c
+++ b/softmmu/device_tree.c
@@ -721,16 +721,24 @@ static void fdt_prop_print_val(const char *propname, const void *data,
     qemu_printf("]\n");
 }
 
-static void fdt_print_node(int node, int depth)
+static void fdt_print_node(int node, int depth, const char *fullpath)
 {
     const struct fdt_property *prop = NULL;
+    const char *nodename = NULL;
     const char *propname = NULL;
     void *fdt = current_machine->fdt;
     int padding = depth * 4;
     int property = 0;
+    int parent = node;
     int prop_size;
 
-    qemu_printf("%*s%s {\n", padding, "", fdt_get_name(fdt, node, NULL));
+    if (fullpath != NULL) {
+        nodename = fullpath;
+    } else {
+        nodename = fdt_get_name(fdt, node, NULL);
+    }
+
+    qemu_printf("%*s%s {\n", padding, "", nodename);
 
     padding += 4;
 
@@ -754,6 +762,10 @@ static void fdt_print_node(int node, int depth)
         }
     }
 
+    fdt_for_each_subnode(node, fdt, parent) {
+        fdt_print_node(node, depth + 1, NULL);
+    }
+
     padding -= 4;
     qemu_printf("%*s}\n", padding, "");
 }
@@ -773,5 +785,5 @@ void fdt_info(const char *fullpath, Error **errp)
         return;
     }
 
-    fdt_print_node(node, 0);
+    fdt_print_node(node, 0, fullpath);
 }
-- 
2.36.1