common/hwconfig.c

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