[coreboot-gerrit] Change in ...coreboot[master]: device_tree: Match debug output format to dtc -O dts output

[Julius Werner (Code Review)]

Hello Patrick Rudolph,

I'd like you to do a code review. Please visit

https://review.coreboot.org/c/coreboot/+/32867

to review the following change.

Change subject: device_tree: Match debug output format to dtc -O dts output
......................................................................

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 
---
M src/lib/device_tree.c
1 file changed, 38 insertions(+), 11 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/67/32867/1

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)