[PATCH for-7.2 v2 18/20] 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 | 21 +++++++++++++++++----
 1 file changed, 17 insertions(+), 4 deletions(-)

diff --git a/softmmu/device_tree.c b/softmmu/device_tree.c
index 9d95e4120b..99d95c1cb9 100644
--- a/softmmu/device_tree.c
+++ b/softmmu/device_tree.c
@@ -728,17 +728,26 @@ static void fdt_prop_format_val(GString *buf, const char *propname,
     g_string_append_printf(buf, "]\n");
 }
 
-static void fdt_format_node(GString *buf, int node, int depth)
+
+static void fdt_format_node(GString *buf, 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;
 
-    g_string_append_printf(buf, "%*s%s {\n", padding, "",
-                           fdt_get_name(fdt, node, NULL));
+    if (fullpath != NULL) {
+        nodename = fullpath;
+    } else {
+        nodename = fdt_get_name(fdt, node, NULL);
+    }
+
+    g_string_append_printf(buf, "%*s%s {\n", padding, "", nodename);
 
     padding += 4;
 
@@ -763,6 +772,10 @@ static void fdt_format_node(GString *buf, int node, int depth)
         }
     }
 
+    fdt_for_each_subnode(node, fdt, parent) {
+        fdt_format_node(buf, node, depth + 1, NULL);
+    }
+
     padding -= 4;
     g_string_append_printf(buf, "%*s}\n", padding, "");
 }
@@ -783,7 +796,7 @@ HumanReadableText *qemu_fdt_qmp_query_fdt(const char *nodepath, Error **errp)
         return NULL;
     }
 
-    fdt_format_node(buf, node, 0);
+    fdt_format_node(buf, node, 0, nodepath);
 
     return human_readable_text_from_str(buf);
 }
-- 
2.36.1