Current File : //usr/src/linux-headers-5.15.0-125-generic/scripts/dtc/fdtget.c
// SPDX-License-Identifier: GPL-2.0-or-later
/*
* 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>
*/
#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;
}
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