commit 0d74653bd46a360466cf5050ea0c102fc11cdc2d
author Julius Werner <jwerner@chromium.org> Mon May 06 19:35:56 2019 -0700
committer Patrick Georgi <pgeorgi@google.com> Tue Jun 04 11:24:34 2019 +0000
tree a7abf5c68748acf1241ff5144b7ce0b8d6c31156
parent 6d5695fac53f52e1f389f420b5428e92de5b8c9c

device_tree: Match debug output format to dtc -O dts output

This patch updates the device tree dumping functions (not compiled by
default but available for debugging) to output properties and nodes in a
format similar to .dts files that is very close to what dtc outputs when
you decompile a .dtb with it. This makes it easier to match device tree
dumps from coreboot with device tree dumps generated by other device
tree tooling.

This patch was adapted from depthcharge's http://crosreview.com/1536386

Change-Id: Ib40e50d906aff05473a70c4fc9b124d63232558c
Signed-off-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/32867
Reviewed-by: Hung-Te Lin <hungte@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/lib/device_tree.c

diff --git a/src/lib/device_tree.c b/src/lib/device_tree.c
index bbcd7c0..3c4bd24 100644
--- a/src/lib/device_tree.c
+++ b/src/lib/device_tree.c
@@ -80,21 +80,36 @@
 
 static void print_indent(int depth)
 {
-	while (depth--)
-		printk(BIOS_DEBUG, "  ");
+	printk(BIOS_DEBUG, "%*s", depth * 8, "");
 }
 
 static void print_property(const struct fdt_property *prop, int depth)
 {
+	int is_string = prop->size > 0 &&
+			((char *)prop->data)[prop->size - 1] == '\0';
+
+	if (is_string)
+		for (const char *c = prop->data; *c != '\0'; c++)
+			if (!isprint(*c))
+				is_string = 0;
+
 	print_indent(depth);
-	printk(BIOS_DEBUG, "prop \"%s\" (%d bytes).\n", prop->name, prop->size);
-	print_indent(depth + 1);
-	for (int i = 0; i < MIN(25, prop->size); i++) {
-		printk(BIOS_DEBUG, "%02x ", ((uint8_t *)prop->data)[i]);
+	if (is_string) {
+		printk(BIOS_DEBUG, "%s = \"%s\";\n",
+		       prop->name, (const char *)prop->data);
+	} else {
+		printk(BIOS_DEBUG, "%s = < ", prop->name);
+		for (int i = 0; i < MIN(128, prop->size); i += 4) {
+			uint32_t val = 0;
+			for (int j = 0; j < MIN(4, prop->size - i); j++)
+				val |= ((uint8_t *)prop->data)[i + j] <<
+					(24 - j * 8);
+			printk(BIOS_DEBUG, "%#.2x ", val);
+		}
+		if (prop->size > 128)
+			printk(BIOS_DEBUG, "...");
+		printk(BIOS_DEBUG, ">;\n");
 	}
-	if (prop->size > 25)
-		printk(BIOS_DEBUG, "...");
-	printk(BIOS_DEBUG, "\n");
 }
 
 static int print_flat_node(const void *blob, uint32_t start_offset, int depth)
@@ -109,7 +124,7 @@
 	offset += size;
 
 	print_indent(depth);
-	printk(BIOS_DEBUG, "name = %s\n", name);
+	printk(BIOS_DEBUG, "%s {\n", name);
 
 	struct fdt_property prop;
 	while ((size = fdt_next_property(blob, offset, &prop))) {
@@ -118,9 +133,14 @@
 		offset += size;
 	}
 
+	printk(BIOS_DEBUG, "\n");	// empty line between props and nodes
+
 	while ((size = print_flat_node(blob, offset, depth + 1)))
 		offset += size;
 
+	print_indent(depth);
+	printk(BIOS_DEBUG, "}\n");
+
 	return offset - start_offset + sizeof(uint32_t);
 }
 
@@ -458,15 +478,22 @@
 static void print_node(const struct device_tree_node *node, int depth)
 {
 	print_indent(depth);
-	printk(BIOS_DEBUG, "name = %s\n", node->name);
+	if (depth == 0)		// root node has no name, print a starting slash
+		printk(BIOS_DEBUG, "/");
+	printk(BIOS_DEBUG, "%s {\n", node->name);
 
 	struct device_tree_property *prop;
 	list_for_each(prop, node->properties, list_node)
 		print_property(&prop->prop, depth + 1);
 
+	printk(BIOS_DEBUG, "\n");	// empty line between props and nodes
+
 	struct device_tree_node *child;
 	list_for_each(child, node->children, list_node)
 		print_node(child, depth + 1);
+
+	print_indent(depth);
+	printk(BIOS_DEBUG, "};\n");
 }
 
 void dt_print_node(const struct device_tree_node *node)