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) && gd->env_valid != ENV_VALID) {
82 printf("WARNING: Calling __hwconfig without a buffer "
83 "and before environment is ready\n");
84 return NULL;
85 }
86 #if CONFIG_IS_ENABLED(ENV_SUPPORT)
87 env_hwconfig = env_get("hwconfig");
88 #endif
89 }
90
91 if (env_hwconfig) {
92 ret = hwconfig_parse(env_hwconfig, strlen(env_hwconfig),
93 opt, ";", ':', arglen);
94 if (ret)
95 return ret;
96 }
97
98 ret = hwconfig_parse(board_hwconfig, strlen(board_hwconfig),
99 opt, ";", ':', arglen);
100 if (ret)
101 return ret;
102
103 return hwconfig_parse(cpu_hwconfig, strlen(cpu_hwconfig),
104 opt, ";", ':', arglen);
105 }
106
107 /*
108 * hwconfig_f - query if a particular hwconfig option is specified
109 * @opt: a string representing an option
110 * @buf: if non-NULL use this buffer to parse, otherwise try env
111 *
112 * This call can be used to find out whether U-Boot should configure
113 * a particular hardware option.
114 *
115 * Returns non-zero value if the hardware option can be used and thus
116 * should be configured, 0 otherwise.
117 *
118 * This function also returns non-zero value if CONFIG_HWCONFIG is
119 * undefined.
120 *
121 * Returning non-zero value without CONFIG_HWCONFIG has its crucial
122 * purpose: the hwconfig() call should be a "transparent" interface,
123 * e.g. if a board doesn't need hwconfig facility, then we assume
124 * that the board file only calls things that are actually used, so
125 * hwconfig() will always return true result.
126 */
hwconfig_f(const char * opt,char * buf)127 int hwconfig_f(const char *opt, char *buf)
128 {
129 return !!__hwconfig(opt, NULL, buf);
130 }
131
132 /*
133 * hwconfig_arg_f - get hwconfig option's argument
134 * @opt: a string representing an option
135 * @arglen: a pointer to an allocated size_t variable
136 * @buf: if non-NULL use this buffer to parse, otherwise try env
137 *
138 * Unlike hwconfig_f() function, this function returns a pointer to the
139 * start of the hwconfig arguments, if option is not found or it has
140 * no specified arguments, the function returns NULL pointer.
141 *
142 * If CONFIG_HWCONFIG is undefined, the function returns "", and
143 * arglen is set to 0.
144 */
hwconfig_arg_f(const char * opt,size_t * arglen,char * buf)145 const char *hwconfig_arg_f(const char *opt, size_t *arglen, char *buf)
146 {
147 return __hwconfig(opt, arglen, buf);
148 }
149
150 /*
151 * hwconfig_arg_cmp_f - compare hwconfig option's argument
152 * @opt: a string representing an option
153 * @arg: a string for comparing an option's argument
154 * @buf: if non-NULL use this buffer to parse, otherwise try env
155 *
156 * This call is similar to hwconfig_arg_f, but instead of returning
157 * hwconfig argument and its length, it is comparing it to @arg.
158 *
159 * Returns non-zero value if @arg matches, 0 otherwise.
160 *
161 * If CONFIG_HWCONFIG is undefined, the function returns a non-zero
162 * value, i.e. the argument matches.
163 */
hwconfig_arg_cmp_f(const char * opt,const char * arg,char * buf)164 int hwconfig_arg_cmp_f(const char *opt, const char *arg, char *buf)
165 {
166 const char *argstr;
167 size_t arglen;
168
169 argstr = hwconfig_arg_f(opt, &arglen, buf);
170 if (!argstr || arglen != strlen(arg))
171 return 0;
172
173 return !strncmp(argstr, arg, arglen);
174 }
175
176 /*
177 * hwconfig_sub_f - query if a particular hwconfig sub-option is specified
178 * @opt: a string representing an option
179 * @subopt: a string representing a sub-option
180 * @buf: if non-NULL use this buffer to parse, otherwise try env
181 *
182 * This call is similar to hwconfig_f(), except that it takes additional
183 * argument @subopt. In this example:
184 * "dr_usb:mode=peripheral"
185 * "dr_usb" is an option, "mode" is a sub-option, and "peripheral" is its
186 * argument.
187 */
hwconfig_sub_f(const char * opt,const char * subopt,char * buf)188 int hwconfig_sub_f(const char *opt, const char *subopt, char *buf)
189 {
190 size_t arglen;
191 const char *arg;
192
193 arg = __hwconfig(opt, &arglen, buf);
194 if (!arg)
195 return 0;
196 return !!hwconfig_parse(arg, arglen, subopt, ",;", '=', NULL);
197 }
198
199 /*
200 * hwconfig_subarg_f - get hwconfig sub-option's argument
201 * @opt: a string representing an option
202 * @subopt: a string representing a sub-option
203 * @subarglen: a pointer to an allocated size_t variable
204 * @buf: if non-NULL use this buffer to parse, otherwise try env
205 *
206 * This call is similar to hwconfig_arg_f(), except that it takes an
207 * additional argument @subopt, and so works with sub-options.
208 */
hwconfig_subarg_f(const char * opt,const char * subopt,size_t * subarglen,char * buf)209 const char *hwconfig_subarg_f(const char *opt, const char *subopt,
210 size_t *subarglen, char *buf)
211 {
212 size_t arglen;
213 const char *arg;
214
215 arg = __hwconfig(opt, &arglen, buf);
216 if (!arg)
217 return NULL;
218 return hwconfig_parse(arg, arglen, subopt, ",;", '=', subarglen);
219 }
220
221 /*
222 * hwconfig_arg_cmp_f - compare hwconfig sub-option's argument
223 * @opt: a string representing an option
224 * @subopt: a string representing a sub-option
225 * @subarg: a string for comparing an sub-option's argument
226 * @buf: if non-NULL use this buffer to parse, otherwise try env
227 *
228 * This call is similar to hwconfig_arg_cmp_f, except that it takes an
229 * additional argument @subopt, and so works with sub-options.
230 */
hwconfig_subarg_cmp_f(const char * opt,const char * subopt,const char * subarg,char * buf)231 int hwconfig_subarg_cmp_f(const char *opt, const char *subopt,
232 const char *subarg, char *buf)
233 {
234 const char *argstr;
235 size_t arglen;
236
237 argstr = hwconfig_subarg_f(opt, subopt, &arglen, buf);
238 if (!argstr || arglen != strlen(subarg))
239 return 0;
240
241 return !strncmp(argstr, subarg, arglen);
242 }
243
244 #ifdef HWCONFIG_TEST
main()245 int main()
246 {
247 const char *ret;
248 size_t len;
249
250 env_set("hwconfig", "key1:subkey1=value1,subkey2=value2;key2:value3;;;;"
251 "key3;:,:=;key4", 1);
252
253 ret = hwconfig_arg("key1", &len);
254 printf("%zd %.*s\n", len, (int)len, ret);
255 assert(len == 29);
256 assert(hwconfig_arg_cmp("key1", "subkey1=value1,subkey2=value2"));
257 assert(!strncmp(ret, "subkey1=value1,subkey2=value2", len));
258
259 ret = hwconfig_subarg("key1", "subkey1", &len);
260 printf("%zd %.*s\n", len, (int)len, ret);
261 assert(len == 6);
262 assert(hwconfig_subarg_cmp("key1", "subkey1", "value1"));
263 assert(!strncmp(ret, "value1", len));
264
265 ret = hwconfig_subarg("key1", "subkey2", &len);
266 printf("%zd %.*s\n", len, (int)len, ret);
267 assert(len == 6);
268 assert(hwconfig_subarg_cmp("key1", "subkey2", "value2"));
269 assert(!strncmp(ret, "value2", len));
270
271 ret = hwconfig_arg("key2", &len);
272 printf("%zd %.*s\n", len, (int)len, ret);
273 assert(len == 6);
274 assert(hwconfig_arg_cmp("key2", "value3"));
275 assert(!strncmp(ret, "value3", len));
276
277 assert(hwconfig("key3"));
278 assert(hwconfig_arg("key4", &len) == NULL);
279 assert(hwconfig_arg("bogus", &len) == NULL);
280
281 unenv_set("hwconfig");
282
283 assert(hwconfig(NULL) == 0);
284 assert(hwconfig("") == 0);
285 assert(hwconfig("key3") == 0);
286
287 return 0;
288 }
289 #endif /* HWCONFIG_TEST */
290