aboutsummaryrefslogtreecommitdiff
path: root/common/hwconfig.c
blob: e5c60ba7a40a415d5bf10447f697336affd24058 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
/*
 * An inteface for configuring a hardware via u-boot environment.
 *
 * Copyright (c) 2009  MontaVista Software, Inc.
 *
 * Author: Anton Vorontsov <avorontsov@ru.mvista.com>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of
 * the License, or (at your option) any later version.
 */

#include <config.h>
#include <common.h>
#include <exports.h>
#include <hwconfig.h>
#include <linux/types.h>
#include <linux/string.h>

static const char *hwconfig_parse(const char *opts, size_t maxlen,
				  const char *opt, char stopch, char eqch,
				  size_t *arglen)
{
	size_t optlen = strlen(opt);
	char *str;
	const char *start = opts;
	const char *end;

next:
	str = strstr(opts, opt);
	end = str + optlen;
	if (end - start > maxlen)
		return NULL;

	if (str && (str == opts || str[-1] == stopch) &&
			(*end == stopch || *end == eqch || *end == '\0')) {
		const char *arg_end;

		if (!arglen)
			return str;

		if (*end != eqch)
			return NULL;

		arg_end = strchr(str, stopch);
		if (!arg_end)
			*arglen = min(maxlen, strlen(str)) - optlen - 1;
		else
			*arglen = arg_end - end - 1;

		return end + 1;
	} else if (str) {
		opts = end;
		goto next;
	}
	return NULL;
}

const char *cpu_hwconfig __attribute__((weak));
const char *board_hwconfig __attribute__((weak));

static const char *__hwconfig(const char *opt, size_t *arglen)
{
	const char *env_hwconfig = getenv("hwconfig");

	if (env_hwconfig)
		return hwconfig_parse(env_hwconfig, strlen(env_hwconfig),
				      opt, ';', ':', arglen);

	if (board_hwconfig)
		return hwconfig_parse(board_hwconfig, strlen(board_hwconfig),
				      opt, ';', ':', arglen);

	if (cpu_hwconfig)
		return hwconfig_parse(cpu_hwconfig, strlen(cpu_hwconfig),
				      opt, ';', ':', arglen);

	return NULL;
}

/*
 * hwconfig - query if a particular hwconfig option is specified
 * @opt:	a string representing an option
 *
 * This call can be used to find out whether U-Boot should configure
 * a particular hardware option.
 *
 * Returns non-zero value if the hardware option can be used and thus
 * should be configured, 0 otherwise.
 *
 * This function also returns non-zero value if CONFIG_HWCONFIG is
 * undefined.
 *
 * Returning non-zero value without CONFIG_HWCONFIG has its crucial
 * purpose: the hwconfig() call should be a "transparent" interface,
 * e.g. if a board doesn't need hwconfig facility, then we assume
 * that the board file only calls things that are actually used, so
 * hwconfig() will always return true result.
 */
int hwconfig(const char *opt)
{
	return !!__hwconfig(opt, NULL);
}

/*
 * hwconfig_arg - get hwconfig option's argument
 * @opt:	a string representing an option
 * @arglen:	a pointer to an allocated size_t variable
 *
 * Unlike hwconfig() function, this function returns a pointer to the
 * start of the hwconfig arguments, if option is not found or it has
 * no specified arguments, the function returns NULL pointer.
 *
 * If CONFIG_HWCONFIG is undefined, the function returns "", and
 * arglen is set to 0.
 */
const char *hwconfig_arg(const char *opt, size_t *arglen)
{
	return __hwconfig(opt, arglen);
}

/*
 * hwconfig_arg_cmp - compare hwconfig option's argument
 * @opt:	a string representing an option
 * @arg:	a string for comparing an option's argument
 *
 * This call is similar to hwconfig_arg, but instead of returning
 * hwconfig argument and its length, it is comparing it to @arg.
 *
 * Returns non-zero value if @arg matches, 0 otherwise.
 *
 * If CONFIG_HWCONFIG is undefined, the function returns a non-zero
 * value, i.e. the argument matches.
 */
int hwconfig_arg_cmp(const char *opt, const char *arg)
{
	const char *argstr;
	size_t arglen;

	argstr = hwconfig_arg(opt, &arglen);
	if (!argstr || arglen != strlen(arg))
		return 0;

	return !strncmp(argstr, arg, arglen);
}

/*
 * hwconfig_sub - query if a particular hwconfig sub-option is specified
 * @opt:	a string representing an option
 * @subopt:	a string representing a sub-option
 *
 * This call is similar to hwconfig(), except that it takes additional
 * argument @subopt. In this example:
 * 	"dr_usb:mode=peripheral"
 * "dr_usb" is an option, "mode" is a sub-option, and "peripheral" is its
 * argument.
 */
int hwconfig_sub(const char *opt, const char *subopt)
{
	size_t arglen;
	const char *arg;

	arg = __hwconfig(opt, &arglen);
	if (!arg)
		return 0;
	return !!hwconfig_parse(arg, arglen, subopt, ',', '=', NULL);
}

/*
 * hwconfig_subarg - get hwconfig sub-option's argument
 * @opt:	a string representing an option
 * @subopt:	a string representing a sub-option
 * @subarglen:	a pointer to an allocated size_t variable
 *
 * This call is similar to hwconfig_arg(), except that it takes an additional
 * argument @subopt, and so works with sub-options.
 */
const char *hwconfig_subarg(const char *opt, const char *subopt,
			    size_t *subarglen)
{
	size_t arglen;
	const char *arg;

	arg = __hwconfig(opt, &arglen);
	if (!arg)
		return NULL;
	return hwconfig_parse(arg, arglen, subopt, ',', '=', subarglen);
}

/*
 * hwconfig_arg_cmp - compare hwconfig sub-option's argument
 * @opt:	a string representing an option
 * @subopt:	a string representing a sub-option
 * @subarg:	a string for comparing an sub-option's argument
 *
 * This call is similar to hwconfig_arg_cmp, except that it takes an additional
 * argument @subopt, and so works with sub-options.
 */
int hwconfig_subarg_cmp(const char *opt, const char *subopt, const char *subarg)
{
	const char *argstr;
	size_t arglen;

	argstr = hwconfig_subarg(opt, subopt, &arglen);
	if (!argstr || arglen != strlen(subarg))
		return 0;

	return !strncmp(argstr, subarg, arglen);
}