xref: /openbmc/linux/scripts/dtc/fdtput.c (revision 1a59d1b8)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Copyright (c) 2011 The Chromium OS Authors. All rights reserved.
4  */
5 
6 #include <assert.h>
7 #include <ctype.h>
8 #include <getopt.h>
9 #include <stdio.h>
10 #include <stdlib.h>
11 #include <string.h>
12 
13 #include <libfdt.h>
14 
15 #include "util.h"
16 
17 /* These are the operations we support */
18 enum oper_type {
19 	OPER_WRITE_PROP,		/* Write a property in a node */
20 	OPER_CREATE_NODE,		/* Create a new node */
21 };
22 
23 struct display_info {
24 	enum oper_type oper;	/* operation to perform */
25 	int type;		/* data type (s/i/u/x or 0 for default) */
26 	int size;		/* data size (1/2/4) */
27 	int verbose;		/* verbose output */
28 	int auto_path;		/* automatically create all path components */
29 };
30 
31 
32 /**
33  * Report an error with a particular node.
34  *
35  * @param name		Node name to report error on
36  * @param namelen	Length of node name, or -1 to use entire string
37  * @param err		Error number to report (-FDT_ERR_...)
38  */
report_error(const char * name,int namelen,int err)39 static void report_error(const char *name, int namelen, int err)
40 {
41 	if (namelen == -1)
42 		namelen = strlen(name);
43 	fprintf(stderr, "Error at '%1.*s': %s\n", namelen, name,
44 		fdt_strerror(err));
45 }
46 
47 /**
48  * Encode a series of arguments in a property value.
49  *
50  * @param disp		Display information / options
51  * @param arg		List of arguments from command line
52  * @param arg_count	Number of arguments (may be 0)
53  * @param valuep	Returns buffer containing value
54  * @param *value_len	Returns length of value encoded
55  */
encode_value(struct display_info * disp,char ** arg,int arg_count,char ** valuep,int * value_len)56 static int encode_value(struct display_info *disp, char **arg, int arg_count,
57 			char **valuep, int *value_len)
58 {
59 	char *value = NULL;	/* holding area for value */
60 	int value_size = 0;	/* size of holding area */
61 	char *ptr;		/* pointer to current value position */
62 	int len;		/* length of this cell/string/byte */
63 	int ival;
64 	int upto;	/* the number of bytes we have written to buf */
65 	char fmt[3];
66 
67 	upto = 0;
68 
69 	if (disp->verbose)
70 		fprintf(stderr, "Decoding value:\n");
71 
72 	fmt[0] = '%';
73 	fmt[1] = disp->type ? disp->type : 'd';
74 	fmt[2] = '\0';
75 	for (; arg_count > 0; arg++, arg_count--, upto += len) {
76 		/* assume integer unless told otherwise */
77 		if (disp->type == 's')
78 			len = strlen(*arg) + 1;
79 		else
80 			len = disp->size == -1 ? 4 : disp->size;
81 
82 		/* enlarge our value buffer by a suitable margin if needed */
83 		if (upto + len > value_size) {
84 			value_size = (upto + len) + 500;
85 			value = realloc(value, value_size);
86 			if (!value) {
87 				fprintf(stderr, "Out of mmory: cannot alloc "
88 					"%d bytes\n", value_size);
89 				return -1;
90 			}
91 		}
92 
93 		ptr = value + upto;
94 		if (disp->type == 's') {
95 			memcpy(ptr, *arg, len);
96 			if (disp->verbose)
97 				fprintf(stderr, "\tstring: '%s'\n", ptr);
98 		} else {
99 			int *iptr = (int *)ptr;
100 			sscanf(*arg, fmt, &ival);
101 			if (len == 4)
102 				*iptr = cpu_to_fdt32(ival);
103 			else
104 				*ptr = (uint8_t)ival;
105 			if (disp->verbose) {
106 				fprintf(stderr, "\t%s: %d\n",
107 					disp->size == 1 ? "byte" :
108 					disp->size == 2 ? "short" : "int",
109 					ival);
110 			}
111 		}
112 	}
113 	*value_len = upto;
114 	*valuep = value;
115 	if (disp->verbose)
116 		fprintf(stderr, "Value size %d\n", upto);
117 	return 0;
118 }
119 
store_key_value(void * blob,const char * node_name,const char * property,const char * buf,int len)120 static int store_key_value(void *blob, const char *node_name,
121 		const char *property, const char *buf, int len)
122 {
123 	int node;
124 	int err;
125 
126 	node = fdt_path_offset(blob, node_name);
127 	if (node < 0) {
128 		report_error(node_name, -1, node);
129 		return -1;
130 	}
131 
132 	err = fdt_setprop(blob, node, property, buf, len);
133 	if (err) {
134 		report_error(property, -1, err);
135 		return -1;
136 	}
137 	return 0;
138 }
139 
140 /**
141  * Create paths as needed for all components of a path
142  *
143  * Any components of the path that do not exist are created. Errors are
144  * reported.
145  *
146  * @param blob		FDT blob to write into
147  * @param in_path	Path to process
148  * @return 0 if ok, -1 on error
149  */
create_paths(void * blob,const char * in_path)150 static int create_paths(void *blob, const char *in_path)
151 {
152 	const char *path = in_path;
153 	const char *sep;
154 	int node, offset = 0;
155 
156 	/* skip leading '/' */
157 	while (*path == '/')
158 		path++;
159 
160 	for (sep = path; *sep; path = sep + 1, offset = node) {
161 		/* equivalent to strchrnul(), but it requires _GNU_SOURCE */
162 		sep = strchr(path, '/');
163 		if (!sep)
164 			sep = path + strlen(path);
165 
166 		node = fdt_subnode_offset_namelen(blob, offset, path,
167 				sep - path);
168 		if (node == -FDT_ERR_NOTFOUND) {
169 			node = fdt_add_subnode_namelen(blob, offset, path,
170 						       sep - path);
171 		}
172 		if (node < 0) {
173 			report_error(path, sep - path, node);
174 			return -1;
175 		}
176 	}
177 
178 	return 0;
179 }
180 
181 /**
182  * Create a new node in the fdt.
183  *
184  * This will overwrite the node_name string. Any error is reported.
185  *
186  * TODO: Perhaps create fdt_path_offset_namelen() so we don't need to do this.
187  *
188  * @param blob		FDT blob to write into
189  * @param node_name	Name of node to create
190  * @return new node offset if found, or -1 on failure
191  */
create_node(void * blob,const char * node_name)192 static int create_node(void *blob, const char *node_name)
193 {
194 	int node = 0;
195 	char *p;
196 
197 	p = strrchr(node_name, '/');
198 	if (!p) {
199 		report_error(node_name, -1, -FDT_ERR_BADPATH);
200 		return -1;
201 	}
202 	*p = '\0';
203 
204 	if (p > node_name) {
205 		node = fdt_path_offset(blob, node_name);
206 		if (node < 0) {
207 			report_error(node_name, -1, node);
208 			return -1;
209 		}
210 	}
211 
212 	node = fdt_add_subnode(blob, node, p + 1);
213 	if (node < 0) {
214 		report_error(p + 1, -1, node);
215 		return -1;
216 	}
217 
218 	return 0;
219 }
220 
do_fdtput(struct display_info * disp,const char * filename,char ** arg,int arg_count)221 static int do_fdtput(struct display_info *disp, const char *filename,
222 		    char **arg, int arg_count)
223 {
224 	char *value;
225 	char *blob;
226 	int len, ret = 0;
227 
228 	blob = utilfdt_read(filename);
229 	if (!blob)
230 		return -1;
231 
232 	switch (disp->oper) {
233 	case OPER_WRITE_PROP:
234 		/*
235 		 * Convert the arguments into a single binary value, then
236 		 * store them into the property.
237 		 */
238 		assert(arg_count >= 2);
239 		if (disp->auto_path && create_paths(blob, *arg))
240 			return -1;
241 		if (encode_value(disp, arg + 2, arg_count - 2, &value, &len) ||
242 			store_key_value(blob, *arg, arg[1], value, len))
243 			ret = -1;
244 		break;
245 	case OPER_CREATE_NODE:
246 		for (; ret >= 0 && arg_count--; arg++) {
247 			if (disp->auto_path)
248 				ret = create_paths(blob, *arg);
249 			else
250 				ret = create_node(blob, *arg);
251 		}
252 		break;
253 	}
254 	if (ret >= 0)
255 		ret = utilfdt_write(filename, blob);
256 
257 	free(blob);
258 	return ret;
259 }
260 
261 static const char *usage_msg =
262 	"fdtput - write a property value to a device tree\n"
263 	"\n"
264 	"The command line arguments are joined together into a single value.\n"
265 	"\n"
266 	"Usage:\n"
267 	"	fdtput <options> <dt file> <node> <property> [<value>...]\n"
268 	"	fdtput -c <options> <dt file> [<node>...]\n"
269 	"Options:\n"
270 	"\t-c\t\tCreate nodes if they don't already exist\n"
271 	"\t-p\t\tAutomatically create nodes as needed for the node path\n"
272 	"\t-t <type>\tType of data\n"
273 	"\t-v\t\tVerbose: display each value decoded from command line\n"
274 	"\t-h\t\tPrint this help\n\n"
275 	USAGE_TYPE_MSG;
276 
usage(const char * msg)277 static void usage(const char *msg)
278 {
279 	if (msg)
280 		fprintf(stderr, "Error: %s\n\n", msg);
281 
282 	fprintf(stderr, "%s", usage_msg);
283 	exit(2);
284 }
285 
main(int argc,char * argv[])286 int main(int argc, char *argv[])
287 {
288 	struct display_info disp;
289 	char *filename = NULL;
290 
291 	memset(&disp, '\0', sizeof(disp));
292 	disp.size = -1;
293 	disp.oper = OPER_WRITE_PROP;
294 	for (;;) {
295 		int c = getopt(argc, argv, "chpt:v");
296 		if (c == -1)
297 			break;
298 
299 		/*
300 		 * TODO: add options to:
301 		 * - delete property
302 		 * - delete node (optionally recursively)
303 		 * - rename node
304 		 * - pack fdt before writing
305 		 * - set amount of free space when writing
306 		 * - expand fdt if value doesn't fit
307 		 */
308 		switch (c) {
309 		case 'c':
310 			disp.oper = OPER_CREATE_NODE;
311 			break;
312 		case 'h':
313 		case '?':
314 			usage(NULL);
315 		case 'p':
316 			disp.auto_path = 1;
317 			break;
318 		case 't':
319 			if (utilfdt_decode_type(optarg, &disp.type,
320 					&disp.size))
321 				usage("Invalid type string");
322 			break;
323 
324 		case 'v':
325 			disp.verbose = 1;
326 			break;
327 		}
328 	}
329 
330 	if (optind < argc)
331 		filename = argv[optind++];
332 	if (!filename)
333 		usage("Missing filename");
334 
335 	argv += optind;
336 	argc -= optind;
337 
338 	if (disp.oper == OPER_WRITE_PROP) {
339 		if (argc < 1)
340 			usage("Missing node");
341 		if (argc < 2)
342 			usage("Missing property");
343 	}
344 
345 	if (do_fdtput(&disp, filename, argv, argc))
346 		return 1;
347 	return 0;
348 }
349