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
29DECLARE_GLOBAL_DATA_PTR;
30
31static 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
40next:
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
71const char cpu_hwconfig[] __attribute__((weak)) = "";
72const char board_hwconfig[] __attribute__((weak)) = "";
73
74static 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 */
127int 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 */
145const 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 */
164int 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 */
188int 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 */
209const 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 */
231int 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
245int 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