[Qemu-devel] [RFC v0 03/10] device_tree: allow property getters to inherit

[Peter A. G. Crosthwaite]

If the inherit flag is set, and the specified property is not found, then search
the parents for it as well.

Signed-off-by: Peter A. G. Crosthwaite <peter.crosthwa...@petalogix.com>
---
 device_tree.c |   11 ++++++++---
 device_tree.h |    4 ++--
 hw/arm_boot.c |    6 ++++--
 3 files changed, 14 insertions(+), 7 deletions(-)

diff --git a/device_tree.c b/device_tree.c
index 3792085..7edbbff 100644
--- a/device_tree.c
+++ b/device_tree.c
@@ -180,7 +180,7 @@ int qemu_devtree_setprop_string(void *fdt, const char 
*node_path,
 
 const void *qemu_devtree_getprop(void *fdt, const char *node_path,
                                  const char *property, int *lenp,
-                                 Error **errp)
+                                 bool inherit, Error **errp)
 {
     int len;
     const void *r;
@@ -189,6 +189,11 @@ const void *qemu_devtree_getprop(void *fdt, const char 
*node_path,
     }
     r = fdt_getprop(fdt, findnode_nofail(fdt, node_path), property, lenp);
     if (!r) {
+        char parent[DT_PATH_LENGTH];
+        if (inherit && !qemu_devtree_getparent(fdt, parent, node_path)) {
+            return qemu_devtree_getprop(fdt, parent, property, lenp, true,
+                                                                errp);
+        }
         fprintf(stderr, "%s: Couldn't get %s/%s: %s\n", __func__,
                 node_path, property, fdt_strerror(*lenp));
         /* FIXME: Be smarter */
@@ -200,11 +205,11 @@ const void *qemu_devtree_getprop(void *fdt, const char 
*node_path,
 
 uint32_t qemu_devtree_getprop_cell(void *fdt, const char *node_path,
                                    const char *property, int offset,
-                                   Error **errp)
+                                   bool inherit, Error **errp)
 {
     int len;
     const uint32_t *p = qemu_devtree_getprop(fdt, node_path, property, &len,
-                                                                        errp);
+                                                                inherit, errp);
     if (errp && *errp) {
         return 0;
     }
diff --git a/device_tree.h b/device_tree.h
index b707085..c3f3b28 100644
--- a/device_tree.h
+++ b/device_tree.h
@@ -33,10 +33,10 @@ int qemu_devtree_setprop_phandle(void *fdt, const char 
*node_path,
                                  const char *target_node_path);
 const void *qemu_devtree_getprop(void *fdt, const char *node_path,
                                  const char *property, int *lenp,
-                                 Error **errp);
+                                 bool inherit, Error **errp);
 uint32_t qemu_devtree_getprop_cell(void *fdt, const char *node_path,
                                    const char *property, int offset,
-                                   Error **errp);
+                                   bool inherit, Error **errp);
 uint32_t qemu_devtree_get_phandle(void *fdt, const char *path);
 uint32_t qemu_devtree_alloc_phandle(void *fdt);
 int qemu_devtree_nop_node(void *fdt, const char *node_path);
diff --git a/hw/arm_boot.c b/hw/arm_boot.c
index 45a7455..d79605c 100644
--- a/hw/arm_boot.c
+++ b/hw/arm_boot.c
@@ -239,8 +239,10 @@ static int load_dtb(target_phys_addr_t addr, const struct 
arm_boot_info *binfo)
     }
     g_free(filename);
 
-    acells = qemu_devtree_getprop_cell(fdt, "/", "#address-cells", 0, &errp);
-    scells = qemu_devtree_getprop_cell(fdt, "/", "#size-cells", 0, &errp);
+    acells = qemu_devtree_getprop_cell(fdt, "/", "#address-cells", 0,
+                                        false, &errp);
+    scells = qemu_devtree_getprop_cell(fdt, "/", "#size-cells", 0,
+                                        false, &errp);
     assert_no_error(errp);
 
     if (acells == 0 || scells == 0) {
-- 
1.7.0.4