diff options
Diffstat (limited to 'dtc/fdtdump.c')
| -rw-r--r-- | dtc/fdtdump.c | 248 |
1 files changed, 248 insertions, 0 deletions
diff --git a/dtc/fdtdump.c b/dtc/fdtdump.c new file mode 100644 index 000000000..d9fb374a5 --- /dev/null +++ b/dtc/fdtdump.c @@ -0,0 +1,248 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * fdtdump.c - Contributed by Pantelis Antoniou <pantelis.antoniou AT gmail.com> + */ + +#include <stdbool.h> +#include <stdint.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <ctype.h> +#include <inttypes.h> + +#include <libfdt.h> +#include <libfdt_env.h> +#include <fdt.h> + +#include "util.h" + +#define FDT_MAGIC_SIZE 4 +#define MAX_VERSION 17 + +#define ALIGN(x, a) (((x) + ((a) - 1)) & ~((a) - 1)) +#define PALIGN(p, a) ((void *)(ALIGN((unsigned long)(p), (a)))) +#define GET_CELL(p) (p += 4, *((const fdt32_t *)(p-4))) + +static const char *tagname(uint32_t tag) +{ + static const char * const names[] = { +#define TN(t) [t] = #t + TN(FDT_BEGIN_NODE), + TN(FDT_END_NODE), + TN(FDT_PROP), + TN(FDT_NOP), + TN(FDT_END), +#undef TN + }; + if (tag < ARRAY_SIZE(names)) + if (names[tag]) + return names[tag]; + return "FDT_???"; +} + +#define dumpf(fmt, args...) \ + do { if (debug) printf("// " fmt, ## args); } while (0) + +static void dump_blob(void *blob, bool debug) +{ + uintptr_t blob_off = (uintptr_t)blob; + struct fdt_header *bph = blob; + uint32_t off_mem_rsvmap = fdt32_to_cpu(bph->off_mem_rsvmap); + uint32_t off_dt = fdt32_to_cpu(bph->off_dt_struct); + uint32_t off_str = fdt32_to_cpu(bph->off_dt_strings); + struct fdt_reserve_entry *p_rsvmap = + (struct fdt_reserve_entry *)((char *)blob + off_mem_rsvmap); + const char *p_struct = (const char *)blob + off_dt; + const char *p_strings = (const char *)blob + off_str; + uint32_t version = fdt32_to_cpu(bph->version); + uint32_t totalsize = fdt32_to_cpu(bph->totalsize); + uint32_t tag; + const char *p, *s, *t; + int depth, sz, shift; + int i; + uint64_t addr, size; + + depth = 0; + shift = 4; + + printf("/dts-v1/;\n"); + printf("// magic:\t\t0x%"PRIx32"\n", fdt32_to_cpu(bph->magic)); + printf("// totalsize:\t\t0x%"PRIx32" (%"PRIu32")\n", + totalsize, totalsize); + printf("// off_dt_struct:\t0x%"PRIx32"\n", off_dt); + printf("// off_dt_strings:\t0x%"PRIx32"\n", off_str); + printf("// off_mem_rsvmap:\t0x%"PRIx32"\n", off_mem_rsvmap); + printf("// version:\t\t%"PRIu32"\n", version); + printf("// last_comp_version:\t%"PRIu32"\n", + fdt32_to_cpu(bph->last_comp_version)); + if (version >= 2) + printf("// boot_cpuid_phys:\t0x%"PRIx32"\n", + fdt32_to_cpu(bph->boot_cpuid_phys)); + + if (version >= 3) + printf("// size_dt_strings:\t0x%"PRIx32"\n", + fdt32_to_cpu(bph->size_dt_strings)); + if (version >= 17) + printf("// size_dt_struct:\t0x%"PRIx32"\n", + fdt32_to_cpu(bph->size_dt_struct)); + printf("\n"); + + for (i = 0; ; i++) { + addr = fdt64_to_cpu(p_rsvmap[i].address); + size = fdt64_to_cpu(p_rsvmap[i].size); + if (addr == 0 && size == 0) + break; + + printf("/memreserve/ %#"PRIx64" %#"PRIx64";\n", + addr, size); + } + + p = p_struct; + while ((tag = fdt32_to_cpu(GET_CELL(p))) != FDT_END) { + + dumpf("%04"PRIxPTR": tag: 0x%08"PRIx32" (%s)\n", + (uintptr_t)p - blob_off - 4, tag, tagname(tag)); + + if (tag == FDT_BEGIN_NODE) { + s = p; + p = PALIGN(p + strlen(s) + 1, 4); + + if (*s == '\0') + s = "/"; + + printf("%*s%s {\n", depth * shift, "", s); + + depth++; + continue; + } + + if (tag == FDT_END_NODE) { + depth--; + + printf("%*s};\n", depth * shift, ""); + continue; + } + + if (tag == FDT_NOP) { + printf("%*s// [NOP]\n", depth * shift, ""); + continue; + } + + if (tag != FDT_PROP) { + fprintf(stderr, "%*s ** Unknown tag 0x%08"PRIx32"\n", depth * shift, "", tag); + break; + } + sz = fdt32_to_cpu(GET_CELL(p)); + s = p_strings + fdt32_to_cpu(GET_CELL(p)); + if (version < 16 && sz >= 8) + p = PALIGN(p, 8); + t = p; + + p = PALIGN(p + sz, 4); + + dumpf("%04"PRIxPTR": string: %s\n", (uintptr_t)s - blob_off, s); + dumpf("%04"PRIxPTR": value\n", (uintptr_t)t - blob_off); + printf("%*s%s", depth * shift, "", s); + utilfdt_print_data(t, sz); + printf(";\n"); + } +} + +/* Usage related data. */ +static const char usage_synopsis[] = "fdtdump [options] <file>"; +static const char usage_short_opts[] = "ds" USAGE_COMMON_SHORT_OPTS; +static struct option const usage_long_opts[] = { + {"debug", no_argument, NULL, 'd'}, + {"scan", no_argument, NULL, 's'}, + USAGE_COMMON_LONG_OPTS +}; +static const char * const usage_opts_help[] = { + "Dump debug information while decoding the file", + "Scan for an embedded fdt in file", + USAGE_COMMON_OPTS_HELP +}; + +static bool valid_header(char *p, off_t len) +{ + if (len < sizeof(struct fdt_header) || + fdt_magic(p) != FDT_MAGIC || + fdt_version(p) > MAX_VERSION || + fdt_last_comp_version(p) > MAX_VERSION || + fdt_totalsize(p) >= len || + fdt_off_dt_struct(p) >= len || + fdt_off_dt_strings(p) >= len) + return 0; + else + return 1; +} + +int main(int argc, char *argv[]) +{ + int opt; + const char *file; + char *buf; + bool debug = false; + bool scan = false; + size_t len; + + fprintf(stderr, "\n" +"**** fdtdump is a low-level debugging tool, not meant for general use.\n" +"**** If you want to decompile a dtb, you probably want\n" +"**** dtc -I dtb -O dts <filename>\n\n" + ); + while ((opt = util_getopt_long()) != EOF) { + switch (opt) { + case_USAGE_COMMON_FLAGS + + case 'd': + debug = true; + break; + case 's': + scan = true; + break; + } + } + if (optind != argc - 1) + usage("missing input filename"); + file = argv[optind]; + + buf = utilfdt_read(file, &len); + if (!buf) + die("could not read: %s\n", file); + + /* try and locate an embedded fdt in a bigger blob */ + if (scan) { + unsigned char smagic[FDT_MAGIC_SIZE]; + char *p = buf; + char *endp = buf + len; + + fdt32_st(smagic, FDT_MAGIC); + + /* poor man's memmem */ + while ((endp - p) >= FDT_MAGIC_SIZE) { + p = memchr(p, smagic[0], endp - p - FDT_MAGIC_SIZE); + if (!p) + break; + if (fdt_magic(p) == FDT_MAGIC) { + /* try and validate the main struct */ + off_t this_len = endp - p; + if (valid_header(p, this_len)) + break; + if (debug) + printf("%s: skipping fdt magic at offset %#tx\n", + file, p - buf); + } + ++p; + } + if (!p || endp - p < sizeof(struct fdt_header)) + die("%s: could not locate fdt magic\n", file); + printf("%s: found fdt at offset %#tx\n", file, p - buf); + buf = p; + } else if (!valid_header(buf, len)) + die("%s: header is not valid\n", file); + + dump_blob(buf, debug); + + return 0; +} |