U-Boot

// SPDX-License-Identifier: GPL-2.0+
/*
 * (C) Copyright 2007
 * Gerald Van Baren, Custom IDEAS, vanbaren@cideas.com
 * Based on code written by:
 *   Pantelis Antoniou <pantelis.antoniou@gmail.com> and
 *   Matthew McClintock <msm@freescale.com>
 */

#include <env.h>
#include <linux/ctype.h>
#include <linux/types.h>
#include <linux/libfdt.h>
#include <fdt_support.h>

#define MAX_LEVEL	32		/* how deeply nested we will go */

bool fdt_printable_str(const void *data, int len)
{
	const char *s = data;
	const char *ss, *se;

	/* zero length is not */
	if (!len)
		return false;

	/* must terminate with zero */
	if (s[len - 1])
		return false;

	se = s + len;

	while (s < se) {
		ss = s;
		while (s < se && *s && isprint((unsigned char)*s))
			s++;

		/* not zero, or not done yet */
		if (*s || s == ss)
			return false;

		s++;
	}

	return true;
}

/*
 * Print the property in the best format, a heuristic guess.  Print as
 * a string, concatenated strings, a byte, word, double word, or (if all
 * else fails) it is printed as a stream of bytes.
 */
static void print_data(const void *data, int len)
{
	int j;
	const char *env_max_dump;
	ulong max_dump = ULONG_MAX;

	/* no data, don't print */
	if (len == 0)
		return;

	env_max_dump = env_get("fdt_max_dump");
	if (env_max_dump)
		max_dump = hextoul(env_max_dump, NULL);

	/*
	 * It is a string, but it may have multiple strings (embedded '\0's).
	 */
	if (fdt_printable_str(data, len)) {
		puts("\"");
		j = 0;
		while (j < len) {
			if (j > 0)
				puts("\", \"");
			puts(data);
			j    += strlen(data) + 1;
			data += strlen(data) + 1;
		}
		puts("\"");
		return;
	}

	if ((len %4) == 0) {
		if (len > max_dump)
			printf("* 0x%p [0x%08x]", data, len);
		else {
			const __be32 *p;

			printf("<");
			for (j = 0, p = data; j < len/4; j++)
				printf("0x%08x%s", fdt32_to_cpu(p[j]),
					j < (len/4 - 1) ? " " : "");
			printf(">");
		}
	} else { /* anything else... hexdump */
		if (len > max_dump)
			printf("* 0x%p [0x%08x]", data, len);
		else {
			const u8 *s;

			printf("[");
			for (j = 0, s = data; j < len; j++)
				printf("%02x%s", s[j], j < len - 1 ? " " : "");
			printf("]");
		}
	}
}

/****************************************************************************/

/*
 * Recursively print (a portion of) an fdt starting from a node.
 * The depth parameter determines how deeply nested the fdt is printed.
 */
int fdt_print(const void *fdt, int nodeoffset, int depth)
{
	static char tabs[MAX_LEVEL+1] =
		"\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t"
		"\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t";
	const void *nodep;	/* property node pointer */
	int  nextoffset;	/* next node offset from libfdt */
	uint32_t tag;		/* tag */
	int  len;		/* length of the property */
	int  level = 0;		/* keep track of nesting level */
	const struct fdt_property *fdt_prop;
	const char *pathp;

	/*
	 * Print the node and all subnodes.
	 */
	while(level >= 0) {
		tag = fdt_next_tag(fdt, nodeoffset, &nextoffset);
		switch(tag) {
		case FDT_BEGIN_NODE:
			pathp = fdt_get_name(fdt, nodeoffset, NULL);
			if (level <= depth) {
				if (pathp == NULL)
					pathp = "/* NULL pointer error */";
				if (*pathp == '\0')
					pathp = "/";	/* root is nameless */
				printf("%s%s {\n",
					&tabs[MAX_LEVEL - level], pathp);
			}
			level++;
			if (level >= MAX_LEVEL) {
				printf("Nested too deep, aborting.\n");
				return 1;
			}
			break;
		case FDT_END_NODE:
			level--;
			if (level <= depth)
				printf("%s};\n", &tabs[MAX_LEVEL - level]);
			if (level == 0) {
				level = -1;		/* exit the loop */
			}
			break;
		case FDT_PROP:
			fdt_prop = fdt_offset_ptr(fdt, nodeoffset,
					sizeof(*fdt_prop));
			pathp    = fdt_string(fdt,
					fdt32_to_cpu(fdt_prop->nameoff));
			len      = fdt32_to_cpu(fdt_prop->len);
			nodep    = fdt_prop->data;
			if (len < 0) {
				printf ("libfdt fdt_getprop(): %s\n",
					fdt_strerror(len));
				return 1;
			} else if (len == 0) {
				/* the property has no value */
				if (level <= depth)
					printf("%s%s;\n",
						&tabs[MAX_LEVEL - level],
						pathp);
			} else {
				if (level <= depth) {
					printf("%s%s = ",
						&tabs[MAX_LEVEL - level],
						pathp);
					print_data (nodep, len);
					printf(";\n");
				}
			}
			break;
		case FDT_NOP:
			printf("%s/* NOP */\n", &tabs[MAX_LEVEL - level]);
			break;
		case FDT_END:
			return 1;
		default:
			if (level <= depth)
				printf("Unknown tag 0x%08X\n", tag);
			return 1;
		}
		nodeoffset = nextoffset;
	}
	return 0;
}

/*
 * Print a portion of the working_fdt starting from a path.
 * The depth parameter determines how deeply nested the fdt is printed.
 */
int fdt_print_path(const char *pathp, char *prop, int depth)
{
	const void *nodep;	/* property node pointer */
	int  nodeoffset;	/* node offset from libfdt */
	int  len;		/* length of the property */

	nodeoffset = fdt_path_offset (working_fdt, pathp);
	if (nodeoffset < 0) {
		/*
		 * Not found or something else bad happened.
		 */
		printf ("libfdt fdt_path_offset() returned %s\n",
			fdt_strerror(nodeoffset));
		return 1;
	}
	/*
	 * The user passed in a property as well as node path.
	 * Print only the given property and then return.
	 */
	if (prop) {
		nodep = fdt_getprop (working_fdt, nodeoffset, prop, &len);
		if (len == 0) {
			/* no property value */
			printf("%s %s\n", pathp, prop);
			return 0;
		} else if (nodep && len > 0) {
			printf("%s = ", prop);
			print_data (nodep, len);
			printf("\n");
			return 0;
		} else {
			printf ("libfdt fdt_getprop(): %s\n",
				fdt_strerror(len));
			return 1;
		}
	}

	/* Print the node and all subnodes using fdt_print() */
	return fdt_print(working_fdt, nodeoffset, depth);
}