[RFC PATCH v4 4/7] device_tree: Add qemu_fdt_add_path

[Yanan Wang <wangyanan55@huawei.com>]

qemu_fdt_add_path() works like qemu_fdt_add_subnode(), except it
also adds all missing subnodes from the given path. We'll use it
in a coming patch where we will add cpu-map to the device tree.

And we also tweak an error message of qemu_fdt_add_subnode().

Cc: David Gibson <david@gibson.dropbear.id.au>
Cc: Alistair Francis <alistair.francis@wdc.com>
Co-developed-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Yanan Wang <wangyanan55@huawei.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Andrew Jones <drjones@redhat.com>
---
 include/sysemu/device_tree.h |  1 +
 softmmu/device_tree.c        | 44 ++++++++++++++++++++++++++++++++++--
 2 files changed, 43 insertions(+), 2 deletions(-)

diff --git a/include/sysemu/device_tree.h b/include/sysemu/device_tree.h
index 8a2fe55622..ef060a9759 100644
--- a/include/sysemu/device_tree.h
+++ b/include/sysemu/device_tree.h
@@ -121,6 +121,7 @@ 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 b621f63fba..3965c834ca 100644
--- a/softmmu/device_tree.c
+++ b/softmmu/device_tree.c
@@ -540,8 +540,8 @@ 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);
     }
 
@@ -549,6 +549,46 @@ int qemu_fdt_add_subnode(void *fdt, const char *name)
     return retval;
 }
 
+/*
+ * qemu_fdt_add_path: Like qemu_fdt_add_subnode(), but will add
+ * all missing subnodes from the given path.
+ */
+int qemu_fdt_add_path(void *fdt, const char *path)
+{
+    const char *name;
+    const char *p = path;
+    int namelen, retval;
+    int parent = 0;
+
+    if (path[0] != '/') {
+        return -1;
+    }
+
+    while (p) {
+        name = p + 1;
+        p = strchr(name, '/');
+        namelen = p != NULL ? p - name : strlen(name);
+
+        retval = fdt_subnode_offset_namelen(fdt, parent, name, namelen);
+        if (retval < 0 && retval != -FDT_ERR_NOTFOUND) {
+            error_report("%s: Unexpected error in finding subnode %.*s: %s",
+                         __func__, namelen, name, fdt_strerror(retval));
+            exit(1);
+        } else if (retval == -FDT_ERR_NOTFOUND) {
+            retval = fdt_add_subnode_namelen(fdt, parent, name, namelen);
+            if (retval < 0) {
+                error_report("%s: Failed to create subnode %.*s: %s",
+                             __func__, namelen, name, fdt_strerror(retval));
+                exit(1);
+            }
+        }
+
+        parent = retval;
+    }
+
+    return retval;
+}
+
 void qemu_fdt_dumpdtb(void *fdt, int size)
 {
     const char *dumpdtb = current_machine->dumpdtb;
-- 
2.23.0