xref: /openbmc/linux/scripts/dtc/fdtget.c (revision 1a59d1b8)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Copyright (c) 2011 The Chromium OS Authors. All rights reserved.
4  *
5  * Portions from U-Boot cmd_fdt.c (C) Copyright 2007
6  * Gerald Van Baren, Custom IDEAS, vanbaren@cideas.com
7  * Based on code written by:
8  *   Pantelis Antoniou <pantelis.antoniou@gmail.com> and
9  *   Matthew McClintock <msm@freescale.com>
10  */
11 
12 #include <assert.h>
13 #include <ctype.h>
14 #include <getopt.h>
15 #include <stdio.h>
16 #include <stdlib.h>
17 #include <string.h>
18 
19 #include <libfdt.h>
20 
21 #include "util.h"
22 
23 enum display_mode {
24 	MODE_SHOW_VALUE,	/* show values for node properties */
25 	MODE_LIST_PROPS,	/* list the properties for a node */
26 	MODE_LIST_SUBNODES,	/* list the subnodes of a node */
27 };
28 
29 /* Holds information which controls our output and options */
30 struct display_info {
31 	int type;		/* data type (s/i/u/x or 0 for default) */
32 	int size;		/* data size (1/2/4) */
33 	enum display_mode mode;	/* display mode that we are using */
34 	const char *default_val; /* default value if node/property not found */
35 };
36 
report_error(const char * where,int err)37 static void report_error(const char *where, int err)
38 {
39 	fprintf(stderr, "Error at '%s': %s\n", where, fdt_strerror(err));
40 }
41 
42 /**
43  * Displays data of a given length according to selected options
44  *
45  * If a specific data type is provided in disp, then this is used. Otherwise
46  * we try to guess the data type / size from the contents.
47  *
48  * @param disp		Display information / options
49  * @param data		Data to display
50  * @param len		Maximum length of buffer
51  * @return 0 if ok, -1 if data does not match format
52  */
show_data(struct display_info * disp,const char * data,int len)53 static int show_data(struct display_info *disp, const char *data, int len)
54 {
55 	int i, size;
56 	const uint8_t *p = (const uint8_t *)data;
57 	const char *s;
58 	int value;
59 	int is_string;
60 	char fmt[3];
61 
62 	/* no data, don't print */
63 	if (len == 0)
64 		return 0;
65 
66 	is_string = (disp->type) == 's' ||
67 		(!disp->type && util_is_printable_string(data, len));
68 	if (is_string) {
69 		if (data[len - 1] != '\0') {
70 			fprintf(stderr, "Unterminated string\n");
71 			return -1;
72 		}
73 		for (s = data; s - data < len; s += strlen(s) + 1) {
74 			if (s != data)
75 				printf(" ");
76 			printf("%s", (const char *)s);
77 		}
78 		return 0;
79 	}
80 	size = disp->size;
81 	if (size == -1) {
82 		size = (len % 4) == 0 ? 4 : 1;
83 	} else if (len % size) {
84 		fprintf(stderr, "Property length must be a multiple of "
85 				"selected data size\n");
86 		return -1;
87 	}
88 	fmt[0] = '%';
89 	fmt[1] = disp->type ? disp->type : 'd';
90 	fmt[2] = '\0';
91 	for (i = 0; i < len; i += size, p += size) {
92 		if (i)
93 			printf(" ");
94 		value = size == 4 ? fdt32_to_cpu(*(const uint32_t *)p) :
95 			size == 2 ? (*p << 8) | p[1] : *p;
96 		printf(fmt, value);
97 	}
98 	return 0;
99 }
100 
101 /**
102  * List all properties in a node, one per line.
103  *
104  * @param blob		FDT blob
105  * @param node		Node to display
106  * @return 0 if ok, or FDT_ERR... if not.
107  */
list_properties(const void * blob,int node)108 static int list_properties(const void *blob, int node)
109 {
110 	const struct fdt_property *data;
111 	const char *name;
112 	int prop;
113 
114 	prop = fdt_first_property_offset(blob, node);
115 	do {
116 		/* Stop silently when there are no more properties */
117 		if (prop < 0)
118 			return prop == -FDT_ERR_NOTFOUND ? 0 : prop;
119 		data = fdt_get_property_by_offset(blob, prop, NULL);
120 		name = fdt_string(blob, fdt32_to_cpu(data->nameoff));
121 		if (name)
122 			puts(name);
123 		prop = fdt_next_property_offset(blob, prop);
124 	} while (1);
125 }
126 
127 #define MAX_LEVEL	32		/* how deeply nested we will go */
128 
129 /**
130  * List all subnodes in a node, one per line
131  *
132  * @param blob		FDT blob
133  * @param node		Node to display
134  * @return 0 if ok, or FDT_ERR... if not.
135  */
list_subnodes(const void * blob,int node)136 static int list_subnodes(const void *blob, int node)
137 {
138 	int nextoffset;		/* next node offset from libfdt */
139 	uint32_t tag;		/* current tag */
140 	int level = 0;		/* keep track of nesting level */
141 	const char *pathp;
142 	int depth = 1;		/* the assumed depth of this node */
143 
144 	while (level >= 0) {
145 		tag = fdt_next_tag(blob, node, &nextoffset);
146 		switch (tag) {
147 		case FDT_BEGIN_NODE:
148 			pathp = fdt_get_name(blob, node, NULL);
149 			if (level <= depth) {
150 				if (pathp == NULL)
151 					pathp = "/* NULL pointer error */";
152 				if (*pathp == '\0')
153 					pathp = "/";	/* root is nameless */
154 				if (level == 1)
155 					puts(pathp);
156 			}
157 			level++;
158 			if (level >= MAX_LEVEL) {
159 				printf("Nested too deep, aborting.\n");
160 				return 1;
161 			}
162 			break;
163 		case FDT_END_NODE:
164 			level--;
165 			if (level == 0)
166 				level = -1;		/* exit the loop */
167 			break;
168 		case FDT_END:
169 			return 1;
170 		case FDT_PROP:
171 			break;
172 		default:
173 			if (level <= depth)
174 				printf("Unknown tag 0x%08X\n", tag);
175 			return 1;
176 		}
177 		node = nextoffset;
178 	}
179 	return 0;
180 }
181 
182 /**
183  * Show the data for a given node (and perhaps property) according to the
184  * display option provided.
185  *
186  * @param blob		FDT blob
187  * @param disp		Display information / options
188  * @param node		Node to display
189  * @param property	Name of property to display, or NULL if none
190  * @return 0 if ok, -ve on error
191  */
show_data_for_item(const void * blob,struct display_info * disp,int node,const char * property)192 static int show_data_for_item(const void *blob, struct display_info *disp,
193 		int node, const char *property)
194 {
195 	const void *value = NULL;
196 	int len, err = 0;
197 
198 	switch (disp->mode) {
199 	case MODE_LIST_PROPS:
200 		err = list_properties(blob, node);
201 		break;
202 
203 	case MODE_LIST_SUBNODES:
204 		err = list_subnodes(blob, node);
205 		break;
206 
207 	default:
208 		assert(property);
209 		value = fdt_getprop(blob, node, property, &len);
210 		if (value) {
211 			if (show_data(disp, value, len))
212 				err = -1;
213 			else
214 				printf("\n");
215 		} else if (disp->default_val) {
216 			puts(disp->default_val);
217 		} else {
218 			report_error(property, len);
219 			err = -1;
220 		}
221 		break;
222 	}
223 
224 	return err;
225 }
226 
227 /**
228  * Run the main fdtget operation, given a filename and valid arguments
229  *
230  * @param disp		Display information / options
231  * @param filename	Filename of blob file
232  * @param arg		List of arguments to process
233  * @param arg_count	Number of arguments
234  * @param return 0 if ok, -ve on error
235  */
do_fdtget(struct display_info * disp,const char * filename,char ** arg,int arg_count,int args_per_step)236 static int do_fdtget(struct display_info *disp, const char *filename,
237 		     char **arg, int arg_count, int args_per_step)
238 {
239 	char *blob;
240 	const char *prop;
241 	int i, node;
242 
243 	blob = utilfdt_read(filename);
244 	if (!blob)
245 		return -1;
246 
247 	for (i = 0; i + args_per_step <= arg_count; i += args_per_step) {
248 		node = fdt_path_offset(blob, arg[i]);
249 		if (node < 0) {
250 			if (disp->default_val) {
251 				puts(disp->default_val);
252 				continue;
253 			} else {
254 				report_error(arg[i], node);
255 				return -1;
256 			}
257 		}
258 		prop = args_per_step == 1 ? NULL : arg[i + 1];
259 
260 		if (show_data_for_item(blob, disp, node, prop))
261 			return -1;
262 	}
263 	return 0;
264 }
265 
266 static const char *usage_msg =
267 	"fdtget - read values from device tree\n"
268 	"\n"
269 	"Each value is printed on a new line.\n\n"
270 	"Usage:\n"
271 	"	fdtget <options> <dt file> [<node> <property>]...\n"
272 	"	fdtget -p <options> <dt file> [<node> ]...\n"
273 	"Options:\n"
274 	"\t-t <type>\tType of data\n"
275 	"\t-p\t\tList properties for each node\n"
276 	"\t-l\t\tList subnodes for each node\n"
277 	"\t-d\t\tDefault value to display when the property is "
278 			"missing\n"
279 	"\t-h\t\tPrint this help\n\n"
280 	USAGE_TYPE_MSG;
281 
usage(const char * msg)282 static void usage(const char *msg)
283 {
284 	if (msg)
285 		fprintf(stderr, "Error: %s\n\n", msg);
286 
287 	fprintf(stderr, "%s", usage_msg);
288 	exit(2);
289 }
290 
main(int argc,char * argv[])291 int main(int argc, char *argv[])
292 {
293 	char *filename = NULL;
294 	struct display_info disp;
295 	int args_per_step = 2;
296 
297 	/* set defaults */
298 	memset(&disp, '\0', sizeof(disp));
299 	disp.size = -1;
300 	disp.mode = MODE_SHOW_VALUE;
301 	for (;;) {
302 		int c = getopt(argc, argv, "d:hlpt:");
303 		if (c == -1)
304 			break;
305 
306 		switch (c) {
307 		case 'h':
308 		case '?':
309 			usage(NULL);
310 
311 		case 't':
312 			if (utilfdt_decode_type(optarg, &disp.type,
313 					&disp.size))
314 				usage("Invalid type string");
315 			break;
316 
317 		case 'p':
318 			disp.mode = MODE_LIST_PROPS;
319 			args_per_step = 1;
320 			break;
321 
322 		case 'l':
323 			disp.mode = MODE_LIST_SUBNODES;
324 			args_per_step = 1;
325 			break;
326 
327 		case 'd':
328 			disp.default_val = optarg;
329 			break;
330 		}
331 	}
332 
333 	if (optind < argc)
334 		filename = argv[optind++];
335 	if (!filename)
336 		usage("Missing filename");
337 
338 	argv += optind;
339 	argc -= optind;
340 
341 	/* Allow no arguments, and silently succeed */
342 	if (!argc)
343 		return 0;
344 
345 	/* Check for node, property arguments */
346 	if (args_per_step == 2 && (argc % 2))
347 		usage("Must have an even number of arguments");
348 
349 	if (do_fdtget(&disp, filename, argv, argc, args_per_step))
350 		return 1;
351 	return 0;
352 }
353