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
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 */
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 */
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 */
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 */
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 */
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
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
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
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