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 <env.h>
15 #include <exports.h>
16 #include <hwconfig.h>
17 #include <log.h>
18 #include <asm/global_data.h>
19 #include <linux/types.h>
20 #include <linux/string.h>
21 #else
22 #include <stdio.h>
23 #include <stdlib.h>
24 #include <string.h>
25 #include <assert.h>
26 #define min(a, b) (((a) < (b)) ? (a) : (b))
27 #endif /* HWCONFIG_TEST */
28
29 DECLARE_GLOBAL_DATA_PTR;
30
hwconfig_parse(const char * opts,size_t maxlen,const char * opt,char * stopchs,char eqch,size_t * arglen)31 static const char *hwconfig_parse(const char *opts, size_t maxlen,
32 const char *opt, char *stopchs, char eqch,
33 size_t *arglen)
34 {
35 size_t optlen = strlen(opt);
36 char *str;
37 const char *start = opts;
38 const char *end;
39
40 next:
41 str = strstr(opts, opt);
42 end = str + optlen;
43 if (end - start > maxlen)
44 return NULL;
45
46 if (str && (str == opts || strpbrk(str - 1, stopchs) == str - 1) &&
47 (strpbrk(end, stopchs) == end || *end == eqch ||
48 *end == '\0')) {
49 const char *arg_end;
50
51 if (!arglen)
52 return str;
53
54 if (*end != eqch)
55 return NULL;
56
57 arg_end = strpbrk(str, stopchs);
58 if (!arg_end)
59 *arglen = min(maxlen, strlen(str)) - optlen - 1;
60 else
61 *arglen = arg_end - end - 1;
62
63 return end + 1;
64 } else if (str) {
65 opts = end;
66 goto next;
67 }
68 return NULL;
69 }
70
71 const char cpu_hwconfig[] __attribute__((weak)) = "";
72 const char board_hwconfig[] __attribute__((weak)) = "";
73
__hwconfig(const char * opt,size_t * arglen,const char * env_hwconfig)74 static const char *__hwconfig(const char *opt, size_t *arglen,
75 const char *env_hwconfig)
76 {
77 const char *ret;
78
79 /* if we are passed a buffer use it, otherwise try the environment */
80 if (!env_hwconfig) {
81 if (!(gd->flags & GD_FLG_ENV_READY)) {
82 printf("WARNING: Calling __hwconfig without a buffer "
83 "and before environment is ready\n");
84 return NULL;
85 }
86 env_hwconfig = env_get("hwconfig");
87 }
88
89 if (env_hwconfig) {
90 ret = hwconfig_parse(env_hwconfig, strlen(env_hwconfig),
91 opt, ";", ':', arglen);
92 if (ret)
93 return ret;
94 }
95
96 ret = hwconfig_parse(board_hwconfig, strlen(board_hwconfig),
97 opt, ";", ':', arglen);
98 if (ret)
99 return ret;
100
101 return hwconfig_parse(cpu_hwconfig, strlen(cpu_hwconfig),
102 opt, ";", ':', arglen);
103 }
104
105 /*
106 * hwconfig_f - query if a particular hwconfig option is specified
107 * @opt: a string representing an option
108 * @buf: if non-NULL use this buffer to parse, otherwise try env
109 *
110 * This call can be used to find out whether U-Boot should configure
111 * a particular hardware option.
112 *
113 * Returns non-zero value if the hardware option can be used and thus
114 * should be configured, 0 otherwise.
115 *
116 * This function also returns non-zero value if CONFIG_HWCONFIG is
117 * undefined.
118 *
119 * Returning non-zero value without CONFIG_HWCONFIG has its crucial
120 * purpose: the hwconfig() call should be a "transparent" interface,
121 * e.g. if a board doesn't need hwconfig facility, then we assume
122 * that the board file only calls things that are actually used, so
123 * hwconfig() will always return true result.
124 */
hwconfig_f(const char * opt,char * buf)125 int hwconfig_f(const char *opt, char *buf)
126 {
127 return !!__hwconfig(opt, NULL, buf);
128 }
129
130 /*
131 * hwconfig_arg_f - get hwconfig option's argument
132 * @opt: a string representing an option
133 * @arglen: a pointer to an allocated size_t variable
134 * @buf: if non-NULL use this buffer to parse, otherwise try env
135 *
136 * Unlike hwconfig_f() function, this function returns a pointer to the
137 * start of the hwconfig arguments, if option is not found or it has
138 * no specified arguments, the function returns NULL pointer.
139 *
140 * If CONFIG_HWCONFIG is undefined, the function returns "", and
141 * arglen is set to 0.
142 */
hwconfig_arg_f(const char * opt,size_t * arglen,char * buf)143 const char *hwconfig_arg_f(const char *opt, size_t *arglen, char *buf)
144 {
145 return __hwconfig(opt, arglen, buf);
146 }
147
148 /*
149 * hwconfig_arg_cmp_f - compare hwconfig option's argument
150 * @opt: a string representing an option
151 * @arg: a string for comparing an option's argument
152 * @buf: if non-NULL use this buffer to parse, otherwise try env
153 *
154 * This call is similar to hwconfig_arg_f, but instead of returning
155 * hwconfig argument and its length, it is comparing it to @arg.
156 *
157 * Returns non-zero value if @arg matches, 0 otherwise.
158 *
159 * If CONFIG_HWCONFIG is undefined, the function returns a non-zero
160 * value, i.e. the argument matches.
161 */
hwconfig_arg_cmp_f(const char * opt,const char * arg,char * buf)162 int hwconfig_arg_cmp_f(const char *opt, const char *arg, char *buf)
163 {
164 const char *argstr;
165 size_t arglen;
166
167 argstr = hwconfig_arg_f(opt, &arglen, buf);
168 if (!argstr || arglen != strlen(arg))
169 return 0;
170
171 return !strncmp(argstr, arg, arglen);
172 }
173
174 /*
175 * hwconfig_sub_f - query if a particular hwconfig sub-option is specified
176 * @opt: a string representing an option
177 * @subopt: a string representing a sub-option
178 * @buf: if non-NULL use this buffer to parse, otherwise try env
179 *
180 * This call is similar to hwconfig_f(), except that it takes additional
181 * argument @subopt. In this example:
182 * "dr_usb:mode=peripheral"
183 * "dr_usb" is an option, "mode" is a sub-option, and "peripheral" is its
184 * argument.
185 */
hwconfig_sub_f(const char * opt,const char * subopt,char * buf)186 int hwconfig_sub_f(const char *opt, const char *subopt, char *buf)
187 {
188 size_t arglen;
189 const char *arg;
190
191 arg = __hwconfig(opt, &arglen, buf);
192 if (!arg)
193 return 0;
194 return !!hwconfig_parse(arg, arglen, subopt, ",;", '=', NULL);
195 }
196
197 /*
198 * hwconfig_subarg_f - get hwconfig sub-option's argument
199 * @opt: a string representing an option
200 * @subopt: a string representing a sub-option
201 * @subarglen: a pointer to an allocated size_t variable
202 * @buf: if non-NULL use this buffer to parse, otherwise try env
203 *
204 * This call is similar to hwconfig_arg_f(), except that it takes an
205 * additional argument @subopt, and so works with sub-options.
206 */
hwconfig_subarg_f(const char * opt,const char * subopt,size_t * subarglen,char * buf)207 const char *hwconfig_subarg_f(const char *opt, const char *subopt,
208 size_t *subarglen, char *buf)
209 {
210 size_t arglen;
211 const char *arg;
212
213 arg = __hwconfig(opt, &arglen, buf);
214 if (!arg)
215 return NULL;
216 return hwconfig_parse(arg, arglen, subopt, ",;", '=', subarglen);
217 }
218
219 /*
220 * hwconfig_arg_cmp_f - compare hwconfig sub-option's argument
221 * @opt: a string representing an option
222 * @subopt: a string representing a sub-option
223 * @subarg: a string for comparing an sub-option's argument
224 * @buf: if non-NULL use this buffer to parse, otherwise try env
225 *
226 * This call is similar to hwconfig_arg_cmp_f, except that it takes an
227 * additional argument @subopt, and so works with sub-options.
228 */
hwconfig_subarg_cmp_f(const char * opt,const char * subopt,const char * subarg,char * buf)229 int hwconfig_subarg_cmp_f(const char *opt, const char *subopt,
230 const char *subarg, char *buf)
231 {
232 const char *argstr;
233 size_t arglen;
234
235 argstr = hwconfig_subarg_f(opt, subopt, &arglen, buf);
236 if (!argstr || arglen != strlen(subarg))
237 return 0;
238
239 return !strncmp(argstr, subarg, arglen);
240 }
241
242 #ifdef HWCONFIG_TEST
main()243 int main()
244 {
245 const char *ret;
246 size_t len;
247
248 env_set("hwconfig", "key1:subkey1=value1,subkey2=value2;key2:value3;;;;"
249 "key3;:,:=;key4", 1);
250
251 ret = hwconfig_arg("key1", &len);
252 printf("%zd %.*s\n", len, (int)len, ret);
253 assert(len == 29);
254 assert(hwconfig_arg_cmp("key1", "subkey1=value1,subkey2=value2"));
255 assert(!strncmp(ret, "subkey1=value1,subkey2=value2", len));
256
257 ret = hwconfig_subarg("key1", "subkey1", &len);
258 printf("%zd %.*s\n", len, (int)len, ret);
259 assert(len == 6);
260 assert(hwconfig_subarg_cmp("key1", "subkey1", "value1"));
261 assert(!strncmp(ret, "value1", len));
262
263 ret = hwconfig_subarg("key1", "subkey2", &len);
264 printf("%zd %.*s\n", len, (int)len, ret);
265 assert(len == 6);
266 assert(hwconfig_subarg_cmp("key1", "subkey2", "value2"));
267 assert(!strncmp(ret, "value2", len));
268
269 ret = hwconfig_arg("key2", &len);
270 printf("%zd %.*s\n", len, (int)len, ret);
271 assert(len == 6);
272 assert(hwconfig_arg_cmp("key2", "value3"));
273 assert(!strncmp(ret, "value3", len));
274
275 assert(hwconfig("key3"));
276 assert(hwconfig_arg("key4", &len) == NULL);
277 assert(hwconfig_arg("bogus", &len) == NULL);
278
279 unenv_set("hwconfig");
280
281 assert(hwconfig(NULL) == 0);
282 assert(hwconfig("") == 0);
283 assert(hwconfig("key3") == 0);
284
285 return 0;
286 }
287 #endif /* HWCONFIG_TEST */
288