Edit File: fdtget.c
/* * Copyright (c) 2011 The Chromium OS Authors. All rights reserved. * * Portions from U-Boot cmd_fdt.c (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> * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License as * published by the Free Software Foundation; either version 2 of * the License, or (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, * MA 02111-1307 USA */ #include <assert.h> #include <ctype.h> #include <getopt.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <libfdt.h> #include "util.h" enum display_mode { MODE_SHOW_VALUE, /* show values for node properties */ MODE_LIST_PROPS, /* list the properties for a node */ MODE_LIST_SUBNODES, /* list the subnodes of a node */ }; /* Holds information which controls our output and options */ struct display_info { int type; /* data type (s/i/u/x or 0 for default) */ int size; /* data size (1/2/4) */ enum display_mode mode; /* display mode that we are using */ const char *default_val; /* default value if node/property not found */ }; static void report_error(const char *where, int err) { fprintf(stderr, "Error at '%s': %s\n", where, fdt_strerror(err)); } /** * Displays data of a given length according to selected options * * If a specific data type is provided in disp, then this is used. Otherwise * we try to guess the data type / size from the contents. * * @param disp Display information / options * @param data Data to display * @param len Maximum length of buffer * @return 0 if ok, -1 if data does not match format */ static int show_data(struct display_info *disp, const char *data, int len) { int i, size; const uint8_t *p = (const uint8_t *)data; const char *s; int value; int is_string; char fmt[3]; /* no data, don't print */ if (len == 0) return 0; is_string = (disp->type) == 's' || (!disp->type && util_is_printable_string(data, len)); if (is_string) { if (data[len - 1] != '\0') { fprintf(stderr, "Unterminated string\n"); return -1; } for (s = data; s - data < len; s += strlen(s) + 1) { if (s != data) printf(" "); printf("%s", (const char *)s); } return 0; } size = disp->size; if (size == -1) { size = (len % 4) == 0 ? 4 : 1; } else if (len % size) { fprintf(stderr, "Property length must be a multiple of " "selected data size\n"); return -1; } fmt[0] = '%'; fmt[1] = disp->type ? disp->type : 'd'; fmt[2] = '\0'; for (i = 0; i < len; i += size, p += size) { if (i) printf(" "); value = size == 4 ? fdt32_to_cpu(*(const uint32_t *)p) : size == 2 ? (*p << 8) | p[1] : *p; printf(fmt, value); } return 0; } /** * List all properties in a node, one per line. * * @param blob FDT blob * @param node Node to display * @return 0 if ok, or FDT_ERR... if not. */ static int list_properties(const void *blob, int node) { const struct fdt_property *data; const char *name; int prop; prop = fdt_first_property_offset(blob, node); do { /* Stop silently when there are no more properties */ if (prop < 0) return prop == -FDT_ERR_NOTFOUND ? 0 : prop; data = fdt_get_property_by_offset(blob, prop, NULL); name = fdt_string(blob, fdt32_to_cpu(data->nameoff)); if (name) puts(name); prop = fdt_next_property_offset(blob, prop); } while (1); } #define MAX_LEVEL 32 /* how deeply nested we will go */ /** * List all subnodes in a node, one per line * * @param blob FDT blob * @param node Node to display * @return 0 if ok, or FDT_ERR... if not. */ static int list_subnodes(const void *blob, int node) { int nextoffset; /* next node offset from libfdt */ uint32_t tag; /* current tag */ int level = 0; /* keep track of nesting level */ const char *pathp; int depth = 1; /* the assumed depth of this node */ while (level >= 0) { tag = fdt_next_tag(blob, node, &nextoffset); switch (tag) { case FDT_BEGIN_NODE: pathp = fdt_get_name(blob, node, NULL); if (level <= depth) { if (pathp == NULL) pathp = "/* NULL pointer error */"; if (*pathp == '\0') pathp = "/"; /* root is nameless */ if (level == 1) puts(pathp); } level++; if (level >= MAX_LEVEL) { printf("Nested too deep, aborting.\n"); return 1; } break; case FDT_END_NODE: level--; if (level == 0) level = -1; /* exit the loop */ break; case FDT_END: return 1; case FDT_PROP: break; default: if (level <= depth) printf("Unknown tag 0x%08X\n", tag); return 1; } node = nextoffset; } return 0; } /** * Show the data for a given node (and perhaps property) according to the * display option provided. * * @param blob FDT blob * @param disp Display information / options * @param node Node to display * @param property Name of property to display, or NULL if none * @return 0 if ok, -ve on error */ static int show_data_for_item(const void *blob, struct display_info *disp, int node, const char *property) { const void *value = NULL; int len, err = 0; switch (disp->mode) { case MODE_LIST_PROPS: err = list_properties(blob, node); break; case MODE_LIST_SUBNODES: err = list_subnodes(blob, node); break; default: assert(property); value = fdt_getprop(blob, node, property, &len); if (value) { if (show_data(disp, value, len)) err = -1; else printf("\n"); } else if (disp->default_val) { puts(disp->default_val); } else { report_error(property, len); err = -1; } break; } return err; } /** * Run the main fdtget operation, given a filename and valid arguments * * @param disp Display information / options * @param filename Filename of blob file * @param arg List of arguments to process * @param arg_count Number of arguments * @param return 0 if ok, -ve on error */ static int do_fdtget(struct display_info *disp, const char *filename, char **arg, int arg_count, int args_per_step) { char *blob; const char *prop; int i, node; blob = utilfdt_read(filename); if (!blob) return -1; for (i = 0; i + args_per_step <= arg_count; i += args_per_step) { node = fdt_path_offset(blob, arg[i]); if (node < 0) { if (disp->default_val) { puts(disp->default_val); continue; } else { report_error(arg[i], node); return -1; } } prop = args_per_step == 1 ? NULL : arg[i + 1]; if (show_data_for_item(blob, disp, node, prop)) return -1; } return 0; } static const char *usage_msg = "fdtget - read values from device tree\n" "\n" "Each value is printed on a new line.\n\n" "Usage:\n" " fdtget <options> <dt file> [<node> <property>]...\n" " fdtget -p <options> <dt file> [<node> ]...\n" "Options:\n" "\t-t <type>\tType of data\n" "\t-p\t\tList properties for each node\n" "\t-l\t\tList subnodes for each node\n" "\t-d\t\tDefault value to display when the property is " "missing\n" "\t-h\t\tPrint this help\n\n" USAGE_TYPE_MSG; static void usage(const char *msg) { if (msg) fprintf(stderr, "Error: %s\n\n", msg); fprintf(stderr, "%s", usage_msg); exit(2); } int main(int argc, char *argv[]) { char *filename = NULL; struct display_info disp; int args_per_step = 2; /* set defaults */ memset(&disp, '\0', sizeof(disp)); disp.size = -1; disp.mode = MODE_SHOW_VALUE; for (;;) { int c = getopt(argc, argv, "d:hlpt:"); if (c == -1) break; switch (c) { case 'h': case '?': usage(NULL); case 't': if (utilfdt_decode_type(optarg, &disp.type, &disp.size)) usage("Invalid type string"); break; case 'p': disp.mode = MODE_LIST_PROPS; args_per_step = 1; break; case 'l': disp.mode = MODE_LIST_SUBNODES; args_per_step = 1; break; case 'd': disp.default_val = optarg; break; } } if (optind < argc) filename = argv[optind++]; if (!filename) usage("Missing filename"); argv += optind; argc -= optind; /* Allow no arguments, and silently succeed */ if (!argc) return 0; /* Check for node, property arguments */ if (args_per_step == 2 && (argc % 2)) usage("Must have an even number of arguments"); if (do_fdtget(&disp, filename, argv, argc, args_per_step)) return 1; return 0; }