util/cbfstool/fmaptool: generate defines for all fmap sections

Add defines for the start and size of the FMAP sections to the
optionally generated header file. For the defines the name of the
corresponding FMAP section is used without the full path, since every
section name should be unique anyway as documented here:
Documentation/lib/flashmap.md

BUG=b:157068645
TEST=Generated header file contains expected defines.
BRANCH=zork

Change-Id: Ie31161cfd304b69a3cb4bb366bf365d979e77c64
Signed-off-by: Felix Held <felix-coreboot@felixheld.de>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/45594
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-by: Furquan Shaikh <furquan@google.com>

util/cbfstool/fmaptool.c

@@ -71,6 +71,29 @@ static void list_cbfs_section_names(FILE *out)
 	fputc('\n', out);
 }
 
+static void write_header_fmap_sections(FILE *header, const struct flashmap_descriptor *root,
+				       unsigned int offset)
+{
+	assert(root);
+	/*
+	 * The offset may only be unknown for the root node in a system where the flash isn't
+	 * memory-mapped.
+	 */
+	if (!root->offset_known && offset != 0)
+		return;
+
+	const unsigned int current_offset = offset + (root->offset_known ? root->offset : 0);
+	fprintf(header, "#define FMAP_SECTION_%s_START %#x\n", root->name, current_offset);
+
+	if (!root->size_known)
+		return;
+
+	fprintf(header, "#define FMAP_SECTION_%s_SIZE %#x\n", root->name, root->size);
+
+	fmd_foreach_child(child, root)
+		write_header_fmap_sections(header, child, current_offset);
+}
+
 static bool write_header(const char *out_fname,
 			 const struct flashmap_descriptor *root,
 			 const int fmap_size)
@@ -93,6 +116,9 @@ static bool write_header(const char *out_fname,
 	fprintf(header, "#define %s %#x\n", HEADER_FMAP_OFFSET, fmap_offset);
 	fprintf(header, "#define %s %#x\n\n", HEADER_FMAP_SIZE, fmap_size);
 
+	write_header_fmap_sections(header, root, 0);
+	fputs("\n", header);
+
 	fputs("#endif\n", header);
 
 	fclose(header);