fdtgrep: Cope with the /aliases node being last

With skeleton.dtsi being dropped it is more likely that the /aliases node
will be last in the device tree. Update fdtgrep to handle this.

Signed-off-by: Simon Glass <sjg@chromium.org>
Tested-by: Masahiro Yamada <yamada.masahiro@socionext.com>

diff --git a/lib/libfdt/fdt_region.c b/lib/libfdt/fdt_region.c
index d2ce4c1c537baed2970850ccb38ada4e627c6c94..8b8a54755549844a3479d7a5d42d2d43e25d24b4 100644 (file)
--- a/lib/libfdt/fdt_region.c
+++ b/lib/libfdt/fdt_region.c
@@ -63,6 +63,30 @@ static int region_list_contains_offset(struct fdt_region_state *info,
        return 0;
 }
 
+/**
+ * fdt_add_alias_regions() - Add regions covering the aliases that we want
+ *
+ * The /aliases node is not automatically included by fdtgrep unless the
+ * command-line arguments cause to be included (or not excluded). However
+ * aliases are special in that we generally want to include those which
+ * reference a node that fdtgrep includes.
+ *
+ * In fact we want to include only aliases for those nodes still included in
+ * the fdt, and drop the other aliases since they point to nodes that will not
+ * be present.
+ *
+ * This function scans the aliases and adds regions for those which we want
+ * to keep.
+ *
+ * @fdt: Device tree to scan
+ * @region: List of regions
+ * @count: Number of regions in the list so far (i.e. starting point for this
+ *     function)
+ * @max_regions: Maximum number of regions in @region list
+ * @info: Place to put the region state
+ * @return number of regions after processing, or -FDT_ERR_NOSPACE if we did
+ * not have enough room in the regions table for the regions we wanted to add.
+ */
 int fdt_add_alias_regions(const void *fdt, struct fdt_region *region, int count,
                          int max_regions, struct fdt_region_state *info)
 {
@@ -74,11 +98,17 @@ int fdt_add_alias_regions(const void *fdt, struct fdt_region *region, int count,
        if (node < 0)
                return -FDT_ERR_NOTFOUND;
 
-       /* The aliases node must come before the others */
+       /*
+        * Find the next node so that we know where the /aliases node ends. We
+        * need special handling if /aliases is the last node.
+        */
        node_end = fdt_next_subnode(fdt, node);
-       if (node_end <= 0)
-               return -FDT_ERR_BADLAYOUT;
-       node_end -= sizeof(fdt32_t);
+       if (node_end == -FDT_ERR_NOTFOUND)
+               /* Move back to the FDT_END_NODE tag of '/' */
+               node_end = fdt_size_dt_struct(fdt) - sizeof(fdt32_t) * 2;
+       else if (node_end < 0) /* other error */
+               return node_end;
+       node_end -= sizeof(fdt32_t);  /* Move to FDT_END_NODE tag of /aliases */
 
        did_alias_header = 0;
        info->region = region;
@@ -109,7 +139,7 @@ int fdt_add_alias_regions(const void *fdt, struct fdt_region *region, int count,
                fdt_add_region(info, base + offset, next - offset);
        }
 
-       /* Add the 'end' tag */
+       /* Add the FDT_END_NODE tag */
        if (did_alias_header)
                fdt_add_region(info, base + node_end, sizeof(fdt32_t));
 

diff --git a/tools/fdtgrep.c b/tools/fdtgrep.c
index b9078273c954b97c6d7740147cd51fc1e42ff4a2..e373c43e3699e3d4387072f4dd89dfa061284ce6 100644 (file)
--- a/tools/fdtgrep.c
+++ b/tools/fdtgrep.c
@@ -810,9 +810,6 @@ static int do_fdtgrep(struct display_info *disp, const char *filename)
                                disp->flags);
                if (count < 0) {
                        report_error("fdt_find_regions", count);
-                       if (count == -FDT_ERR_BADLAYOUT)
-                               fprintf(stderr,
-                                       "/aliases node must come before all other nodes\n");
                        return -1;
                }
                if (count <= max_regions)