xref: /openbmc/u-boot/common/hwconfig.c (revision ef64e782)
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * An inteface for configuring a hardware via u-boot environment.
4  *
5  * Copyright (c) 2009  MontaVista Software, Inc.
6  * Copyright 2011 Freescale Semiconductor, Inc.
7  *
8  * Author: Anton Vorontsov <avorontsov@ru.mvista.com>
9  */
10 
11 #ifndef HWCONFIG_TEST
12 #include <config.h>
13 #include <common.h>
14 #include <exports.h>
15 #include <hwconfig.h>
16 #include <linux/types.h>
17 #include <linux/string.h>
18 #else
19 #include <stdio.h>
20 #include <stdlib.h>
21 #include <string.h>
22 #include <assert.h>
23 #define min(a, b) (((a) < (b)) ? (a) : (b))
24 #endif /* HWCONFIG_TEST */
25 
26 DECLARE_GLOBAL_DATA_PTR;
27 
28 static const char *hwconfig_parse(const char *opts, size_t maxlen,
29 				  const char *opt, char *stopchs, char eqch,
30 				  size_t *arglen)
31 {
32 	size_t optlen = strlen(opt);
33 	char *str;
34 	const char *start = opts;
35 	const char *end;
36 
37 next:
38 	str = strstr(opts, opt);
39 	end = str + optlen;
40 	if (end - start > maxlen)
41 		return NULL;
42 
43 	if (str && (str == opts || strpbrk(str - 1, stopchs) == str - 1) &&
44 			(strpbrk(end, stopchs) == end || *end == eqch ||
45 			 *end == '\0')) {
46 		const char *arg_end;
47 
48 		if (!arglen)
49 			return str;
50 
51 		if (*end != eqch)
52 			return NULL;
53 
54 		arg_end = strpbrk(str, stopchs);
55 		if (!arg_end)
56 			*arglen = min(maxlen, strlen(str)) - optlen - 1;
57 		else
58 			*arglen = arg_end - end - 1;
59 
60 		return end + 1;
61 	} else if (str) {
62 		opts = end;
63 		goto next;
64 	}
65 	return NULL;
66 }
67 
68 const char cpu_hwconfig[] __attribute__((weak)) = "";
69 const char board_hwconfig[] __attribute__((weak)) = "";
70 
71 static const char *__hwconfig(const char *opt, size_t *arglen,
72 			      const char *env_hwconfig)
73 {
74 	const char *ret;
75 
76 	/* if we are passed a buffer use it, otherwise try the environment */
77 	if (!env_hwconfig) {
78 		if (!(gd->flags & GD_FLG_ENV_READY)) {
79 			printf("WARNING: Calling __hwconfig without a buffer "
80 					"and before environment is ready\n");
81 			return NULL;
82 		}
83 		env_hwconfig = env_get("hwconfig");
84 	}
85 
86 	if (env_hwconfig) {
87 		ret = hwconfig_parse(env_hwconfig, strlen(env_hwconfig),
88 				      opt, ";", ':', arglen);
89 		if (ret)
90 			return ret;
91 	}
92 
93 	ret = hwconfig_parse(board_hwconfig, strlen(board_hwconfig),
94 			opt, ";", ':', arglen);
95 	if (ret)
96 		return ret;
97 
98 	return hwconfig_parse(cpu_hwconfig, strlen(cpu_hwconfig),
99 			opt, ";", ':', arglen);
100 }
101 
102 /*
103  * hwconfig_f - query if a particular hwconfig option is specified
104  * @opt:	a string representing an option
105  * @buf:	if non-NULL use this buffer to parse, otherwise try env
106  *
107  * This call can be used to find out whether U-Boot should configure
108  * a particular hardware option.
109  *
110  * Returns non-zero value if the hardware option can be used and thus
111  * should be configured, 0 otherwise.
112  *
113  * This function also returns non-zero value if CONFIG_HWCONFIG is
114  * undefined.
115  *
116  * Returning non-zero value without CONFIG_HWCONFIG has its crucial
117  * purpose: the hwconfig() call should be a "transparent" interface,
118  * e.g. if a board doesn't need hwconfig facility, then we assume
119  * that the board file only calls things that are actually used, so
120  * hwconfig() will always return true result.
121  */
122 int hwconfig_f(const char *opt, char *buf)
123 {
124 	return !!__hwconfig(opt, NULL, buf);
125 }
126 
127 /*
128  * hwconfig_arg_f - get hwconfig option's argument
129  * @opt:	a string representing an option
130  * @arglen:	a pointer to an allocated size_t variable
131  * @buf:	if non-NULL use this buffer to parse, otherwise try env
132  *
133  * Unlike hwconfig_f() function, this function returns a pointer to the
134  * start of the hwconfig arguments, if option is not found or it has
135  * no specified arguments, the function returns NULL pointer.
136  *
137  * If CONFIG_HWCONFIG is undefined, the function returns "", and
138  * arglen is set to 0.
139  */
140 const char *hwconfig_arg_f(const char *opt, size_t *arglen, char *buf)
141 {
142 	return __hwconfig(opt, arglen, buf);
143 }
144 
145 /*
146  * hwconfig_arg_cmp_f - compare hwconfig option's argument
147  * @opt:	a string representing an option
148  * @arg:	a string for comparing an option's argument
149  * @buf:	if non-NULL use this buffer to parse, otherwise try env
150  *
151  * This call is similar to hwconfig_arg_f, but instead of returning
152  * hwconfig argument and its length, it is comparing it to @arg.
153  *
154  * Returns non-zero value if @arg matches, 0 otherwise.
155  *
156  * If CONFIG_HWCONFIG is undefined, the function returns a non-zero
157  * value, i.e. the argument matches.
158  */
159 int hwconfig_arg_cmp_f(const char *opt, const char *arg, char *buf)
160 {
161 	const char *argstr;
162 	size_t arglen;
163 
164 	argstr = hwconfig_arg_f(opt, &arglen, buf);
165 	if (!argstr || arglen != strlen(arg))
166 		return 0;
167 
168 	return !strncmp(argstr, arg, arglen);
169 }
170 
171 /*
172  * hwconfig_sub_f - query if a particular hwconfig sub-option is specified
173  * @opt:	a string representing an option
174  * @subopt:	a string representing a sub-option
175  * @buf:	if non-NULL use this buffer to parse, otherwise try env
176  *
177  * This call is similar to hwconfig_f(), except that it takes additional
178  * argument @subopt. In this example:
179  * 	"dr_usb:mode=peripheral"
180  * "dr_usb" is an option, "mode" is a sub-option, and "peripheral" is its
181  * argument.
182  */
183 int hwconfig_sub_f(const char *opt, const char *subopt, char *buf)
184 {
185 	size_t arglen;
186 	const char *arg;
187 
188 	arg = __hwconfig(opt, &arglen, buf);
189 	if (!arg)
190 		return 0;
191 	return !!hwconfig_parse(arg, arglen, subopt, ",;", '=', NULL);
192 }
193 
194 /*
195  * hwconfig_subarg_f - get hwconfig sub-option's argument
196  * @opt:	a string representing an option
197  * @subopt:	a string representing a sub-option
198  * @subarglen:	a pointer to an allocated size_t variable
199  * @buf:	if non-NULL use this buffer to parse, otherwise try env
200  *
201  * This call is similar to hwconfig_arg_f(), except that it takes an
202  * additional argument @subopt, and so works with sub-options.
203  */
204 const char *hwconfig_subarg_f(const char *opt, const char *subopt,
205 			      size_t *subarglen, char *buf)
206 {
207 	size_t arglen;
208 	const char *arg;
209 
210 	arg = __hwconfig(opt, &arglen, buf);
211 	if (!arg)
212 		return NULL;
213 	return hwconfig_parse(arg, arglen, subopt, ",;", '=', subarglen);
214 }
215 
216 /*
217  * hwconfig_arg_cmp_f - compare hwconfig sub-option's argument
218  * @opt:	a string representing an option
219  * @subopt:	a string representing a sub-option
220  * @subarg:	a string for comparing an sub-option's argument
221  * @buf:	if non-NULL use this buffer to parse, otherwise try env
222  *
223  * This call is similar to hwconfig_arg_cmp_f, except that it takes an
224  * additional argument @subopt, and so works with sub-options.
225  */
226 int hwconfig_subarg_cmp_f(const char *opt, const char *subopt,
227 			  const char *subarg, char *buf)
228 {
229 	const char *argstr;
230 	size_t arglen;
231 
232 	argstr = hwconfig_subarg_f(opt, subopt, &arglen, buf);
233 	if (!argstr || arglen != strlen(subarg))
234 		return 0;
235 
236 	return !strncmp(argstr, subarg, arglen);
237 }
238 
239 #ifdef HWCONFIG_TEST
240 int main()
241 {
242 	const char *ret;
243 	size_t len;
244 
245 	env_set("hwconfig", "key1:subkey1=value1,subkey2=value2;key2:value3;;;;"
246 			   "key3;:,:=;key4", 1);
247 
248 	ret = hwconfig_arg("key1", &len);
249 	printf("%zd %.*s\n", len, (int)len, ret);
250 	assert(len == 29);
251 	assert(hwconfig_arg_cmp("key1", "subkey1=value1,subkey2=value2"));
252 	assert(!strncmp(ret, "subkey1=value1,subkey2=value2", len));
253 
254 	ret = hwconfig_subarg("key1", "subkey1", &len);
255 	printf("%zd %.*s\n", len, (int)len, ret);
256 	assert(len == 6);
257 	assert(hwconfig_subarg_cmp("key1", "subkey1", "value1"));
258 	assert(!strncmp(ret, "value1", len));
259 
260 	ret = hwconfig_subarg("key1", "subkey2", &len);
261 	printf("%zd %.*s\n", len, (int)len, ret);
262 	assert(len == 6);
263 	assert(hwconfig_subarg_cmp("key1", "subkey2", "value2"));
264 	assert(!strncmp(ret, "value2", len));
265 
266 	ret = hwconfig_arg("key2", &len);
267 	printf("%zd %.*s\n", len, (int)len, ret);
268 	assert(len == 6);
269 	assert(hwconfig_arg_cmp("key2", "value3"));
270 	assert(!strncmp(ret, "value3", len));
271 
272 	assert(hwconfig("key3"));
273 	assert(hwconfig_arg("key4", &len) == NULL);
274 	assert(hwconfig_arg("bogus", &len) == NULL);
275 
276 	unenv_set("hwconfig");
277 
278 	assert(hwconfig(NULL) == 0);
279 	assert(hwconfig("") == 0);
280 	assert(hwconfig("key3") == 0);
281 
282 	return 0;
283 }
284 #endif /* HWCONFIG_TEST */
285