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