libfdt: Add fdt_find_regions()

Add a function to find regions in device tree given a list of nodes to
include and properties to exclude.

See the header file for full documentation.

Signed-off-by: Simon Glass <sjg@chromium.org>

1 files changed, 129 insertions, 0 deletions

diff --git a/lib/libfdt/fdt_wip.c b/lib/libfdt/fdt_wip.c
index 63e67b7..b9e3c4a 100644
--- a/lib/libfdt/fdt_wip.c
+++ b/lib/libfdt/fdt_wip.c
@@ -120,3 +120,132 @@ int fdt_nop_node(void *fdt, int nodeoffset)
 			endoffset - nodeoffset);
 	return 0;
 }
+
+#define FDT_MAX_DEPTH	32
+
+static int str_in_list(const char *str, char * const list[], int count)
+{
+	int i;
+
+	for (i = 0; i < count; i++)
+		if (!strcmp(list[i], str))
+			return 1;
+
+	return 0;
+}
+
+int fdt_find_regions(const void *fdt, char * const inc[], int inc_count,
+		     char * const exc_prop[], int exc_prop_count,
+		     struct fdt_region region[], int max_regions,
+		     char *path, int path_len, int add_string_tab)
+{
+	int stack[FDT_MAX_DEPTH];
+	char *end;
+	int nextoffset = 0;
+	uint32_t tag;
+	int count = 0;
+	int start = -1;
+	int depth = -1;
+	int want = 0;
+	int base = fdt_off_dt_struct(fdt);
+
+	end = path;
+	*end = '\0';
+	do {
+		const struct fdt_property *prop;
+		const char *name;
+		const char *str;
+		int include = 0;
+		int stop_at = 0;
+		int offset;
+		int len;
+
+		offset = nextoffset;
+		tag = fdt_next_tag(fdt, offset, &nextoffset);
+		stop_at = nextoffset;
+
+		switch (tag) {
+		case FDT_PROP:
+			include = want >= 2;
+			stop_at = offset;
+			prop = fdt_get_property_by_offset(fdt, offset, NULL);
+			str = fdt_string(fdt, fdt32_to_cpu(prop->nameoff));
+			if (str_in_list(str, exc_prop, exc_prop_count))
+				include = 0;
+			break;
+
+		case FDT_NOP:
+			include = want >= 2;
+			stop_at = offset;
+			break;
+
+		case FDT_BEGIN_NODE:
+			depth++;
+			if (depth == FDT_MAX_DEPTH)
+				return -FDT_ERR_BADSTRUCTURE;
+			name = fdt_get_name(fdt, offset, &len);
+			if (end - path + 2 + len >= path_len)
+				return -FDT_ERR_NOSPACE;
+			if (end != path + 1)
+				*end++ = '/';
+			strcpy(end, name);
+			end += len;
+			stack[depth] = want;
+			if (want == 1)
+				stop_at = offset;
+			if (str_in_list(path, inc, inc_count))
+				want = 2;
+			else if (want)
+				want--;
+			else
+				stop_at = offset;
+			include = want;
+			break;
+
+		case FDT_END_NODE:
+			include = want;
+			want = stack[depth--];
+			while (end > path && *--end != '/')
+				;
+			*end = '\0';
+			break;
+
+		case FDT_END:
+			include = 1;
+			break;
+		}
+
+		if (include && start == -1) {
+			/* Should we merge with previous? */
+			if (count && count <= max_regions &&
+			    offset == region[count - 1].offset +
+					region[count - 1].size - base)
+				start = region[--count].offset - base;
+			else
+				start = offset;
+		}
+
+		if (!include && start != -1) {
+			if (count < max_regions) {
+				region[count].offset = base + start;
+				region[count].size = stop_at - start;
+			}
+			count++;
+			start = -1;
+		}
+	} while (tag != FDT_END);
+
+	if (nextoffset != fdt_size_dt_struct(fdt))
+		return -FDT_ERR_BADLAYOUT;
+
+	/* Add a region for the END tag and the string table */
+	if (count < max_regions) {
+		region[count].offset = base + start;
+		region[count].size = nextoffset - start;
+		if (add_string_tab)
+			region[count].size += fdt_size_dt_strings(fdt);
+	}
+	count++;
+
+	return count;
+}