[RFC PATCH 1/5] device_tree: Add qemu_fdt_add_path

[Ying Fang]

qemu_fdt_add_path() works like qemu_fdt_add_subnode(), except
it also adds any missing parent nodes. We also tweak an error
message of qemu_fdt_add_subnode().

Signed-off-by: Andrew Jones <drjo...@redhat.com>
Signed-off-by: Ying Fang <fangyi...@huawei.com>
---
 include/sysemu/device_tree.h |  1 +
 softmmu/device_tree.c        | 45 ++++++++++++++++++++++++++++++++++--
 2 files changed, 44 insertions(+), 2 deletions(-)

diff --git a/include/sysemu/device_tree.h b/include/sysemu/device_tree.h
index 982c89345f..15fb98af98 100644
--- a/include/sysemu/device_tree.h
+++ b/include/sysemu/device_tree.h
@@ -104,6 +104,7 @@ uint32_t qemu_fdt_get_phandle(void *fdt, const char *path);
 uint32_t qemu_fdt_alloc_phandle(void *fdt);
 int qemu_fdt_nop_node(void *fdt, const char *node_path);
 int qemu_fdt_add_subnode(void *fdt, const char *name);
+int qemu_fdt_add_path(void *fdt, const char *path);
 
 #define qemu_fdt_setprop_cells(fdt, node_path, property, ...)                 \
     do {                                                                      \
diff --git a/softmmu/device_tree.c b/softmmu/device_tree.c
index b9a3ddc518..1e3857ca0c 100644
--- a/softmmu/device_tree.c
+++ b/softmmu/device_tree.c
@@ -515,8 +515,8 @@ int qemu_fdt_add_subnode(void *fdt, const char *name)
 
     retval = fdt_add_subnode(fdt, parent, basename);
     if (retval < 0) {
-        error_report("FDT: Failed to create subnode %s: %s", name,
-                     fdt_strerror(retval));
+        error_report("%s: Failed to create subnode %s: %s",
+                     __func__, name, fdt_strerror(retval));
         exit(1);
     }
 
@@ -524,6 +524,47 @@ int qemu_fdt_add_subnode(void *fdt, const char *name)
     return retval;
 }
 
+/*
+ * Like qemu_fdt_add_subnode(), but will add all missing
+ * subnodes in the path.
+ */
+int qemu_fdt_add_path(void *fdt, const char *path)
+{
+    char *dupname, *basename, *p;
+    int parent, retval = -1;
+
+    if (path[0] != '/') {
+        return retval;
+    }
+
+    parent = fdt_path_offset(fdt, "/");
+    p = dupname = g_strdup(path);
+
+    while (p) {
+        *p = '/';
+        basename = p + 1;
+        p = strchr(p + 1, '/');
+        if (p) {
+            *p = '\0';
+        }
+        retval = fdt_path_offset(fdt, dupname);
+        if (retval < 0 && retval != -FDT_ERR_NOTFOUND) {
+            error_report("%s: Invalid path %s: %s",
+                         __func__, path, fdt_strerror(retval));
+            exit(1);
+        } else if (retval == -FDT_ERR_NOTFOUND) {
+            retval = fdt_add_subnode(fdt, parent, basename);
+            if (retval < 0) {
+                break;
+            }
+        }
+        parent = retval;
+    }
+
+    g_free(dupname);
+    return retval;
+}
+
 void qemu_fdt_dumpdtb(void *fdt, int size)
 {
     const char *dumpdtb = current_machine->dumpdtb;
-- 
2.23.0