common/hwconfig.c

   1 /*
   2  * An inteface for configuring a hardware via u-boot environment.
   3  *
   4  * Copyright (c) 2009  MontaVista Software, Inc.
   5  *
   6  * Author: Anton Vorontsov <avorontsov@ru.mvista.com>
   7  *
   8  * This program is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU General Public License as
  10  * published by the Free Software Foundation; either version 2 of
  11  * the License, or (at your option) any later version.
  12  */
  13
  14 #ifndef HWCONFIG_TEST
  15 #include <config.h>
  16 #include <common.h>
  17 #include <exports.h>
  18 #include <hwconfig.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
  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
  74 #define HWCONFIG_PRE_RELOC_BUF_SIZE     128
  75
  76 static const char *__hwconfig(const char *opt, size_t *arglen)
  77 {
  78         const char *env_hwconfig = NULL;
  79         char buf[HWCONFIG_PRE_RELOC_BUF_SIZE];
  80
  81         if (gd->flags & GD_FLG_ENV_READY) {
  82                 env_hwconfig = getenv("hwconfig");
  83         } else {
  84                 /*
  85                  * Use our own on stack based buffer before relocation to allow
  86                  * accessing longer hwconfig strings that might be in the
  87                  * environment before we've relocated.  This is pretty fragile
  88                  * on both the use of stack and if the buffer is big enough.
  89                  * However we will get a warning from getenv_f for the later.
  90                  */
  91                 if ((getenv_f("hwconfig", buf, sizeof(buf))) > 0)
  92                         env_hwconfig = buf;
  93         }
  94
  95         if (env_hwconfig)
  96                 return hwconfig_parse(env_hwconfig, strlen(env_hwconfig),
  97                                       opt, ";", ':', arglen);
  98
  99         return hwconfig_parse(board_hwconfig, strlen(board_hwconfig),
 100                         opt, ";", ':', arglen);
 101
 102         return hwconfig_parse(cpu_hwconfig, strlen(cpu_hwconfig),
 103                         opt, ";", ':', arglen);
 104
 105         return NULL;
 106 }
 107
 108 /*
 109  * hwconfig - query if a particular hwconfig option is specified
 110  * @opt:        a string representing an option
 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  */
 127 int hwconfig(const char *opt)
 128 {
 129         return !!__hwconfig(opt, NULL);
 130 }
 131
 132 /*
 133  * hwconfig_arg - get hwconfig option's argument
 134  * @opt:        a string representing an option
 135  * @arglen:     a pointer to an allocated size_t variable
 136  *
 137  * Unlike hwconfig() function, this function returns a pointer to the
 138  * start of the hwconfig arguments, if option is not found or it has
 139  * no specified arguments, the function returns NULL pointer.
 140  *
 141  * If CONFIG_HWCONFIG is undefined, the function returns "", and
 142  * arglen is set to 0.
 143  */
 144 const char *hwconfig_arg(const char *opt, size_t *arglen)
 145 {
 146         return __hwconfig(opt, arglen);
 147 }
 148
 149 /*
 150  * hwconfig_arg_cmp - compare hwconfig option's argument
 151  * @opt:        a string representing an option
 152  * @arg:        a string for comparing an option's argument
 153  *
 154  * This call is similar to hwconfig_arg, 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  */
 162 int hwconfig_arg_cmp(const char *opt, const char *arg)
 163 {
 164         const char *argstr;
 165         size_t arglen;
 166
 167         argstr = hwconfig_arg(opt, &arglen);
 168         if (!argstr || arglen != strlen(arg))
 169                 return 0;
 170
 171         return !strncmp(argstr, arg, arglen);
 172 }
 173
 174 /*
 175  * hwconfig_sub - 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  *
 179  * This call is similar to hwconfig(), except that it takes additional
 180  * argument @subopt. In this example:
 181  *      "dr_usb:mode=peripheral"
 182  * "dr_usb" is an option, "mode" is a sub-option, and "peripheral" is its
 183  * argument.
 184  */
 185 int hwconfig_sub(const char *opt, const char *subopt)
 186 {
 187         size_t arglen;
 188         const char *arg;
 189
 190         arg = __hwconfig(opt, &arglen);
 191         if (!arg)
 192                 return 0;
 193         return !!hwconfig_parse(arg, arglen, subopt, ",;", '=', NULL);
 194 }
 195
 196 /*
 197  * hwconfig_subarg - get hwconfig sub-option's argument
 198  * @opt:        a string representing an option
 199  * @subopt:     a string representing a sub-option
 200  * @subarglen:  a pointer to an allocated size_t variable
 201  *
 202  * This call is similar to hwconfig_arg(), except that it takes an additional
 203  * argument @subopt, and so works with sub-options.
 204  */
 205 const char *hwconfig_subarg(const char *opt, const char *subopt,
 206                             size_t *subarglen)
 207 {
 208         size_t arglen;
 209         const char *arg;
 210
 211         arg = __hwconfig(opt, &arglen);
 212         if (!arg)
 213                 return NULL;
 214         return hwconfig_parse(arg, arglen, subopt, ",;", '=', subarglen);
 215 }
 216
 217 /*
 218  * hwconfig_arg_cmp - 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  *
 223  * This call is similar to hwconfig_arg_cmp, except that it takes an additional
 224  * argument @subopt, and so works with sub-options.
 225  */
 226 int hwconfig_subarg_cmp(const char *opt, const char *subopt, const char *subarg)
 227 {
 228         const char *argstr;
 229         size_t arglen;
 230
 231         argstr = hwconfig_subarg(opt, subopt, &arglen);
 232         if (!argstr || arglen != strlen(subarg))
 233                 return 0;
 234
 235         return !strncmp(argstr, subarg, arglen);
 236 }
 237
 238 #ifdef HWCONFIG_TEST
 239 int main()
 240 {
 241         const char *ret;
 242         size_t len;
 243
 244         setenv("hwconfig", "key1:subkey1=value1,subkey2=value2;key2:value3;;;;"
 245                            "key3;:,:=;key4", 1);
 246
 247         ret = hwconfig_arg("key1", &len);
 248         printf("%zd %.*s\n", len, (int)len, ret);
 249         assert(len == 29);
 250         assert(hwconfig_arg_cmp("key1", "subkey1=value1,subkey2=value2"));
 251         assert(!strncmp(ret, "subkey1=value1,subkey2=value2", len));
 252
 253         ret = hwconfig_subarg("key1", "subkey1", &len);
 254         printf("%zd %.*s\n", len, (int)len, ret);
 255         assert(len == 6);
 256         assert(hwconfig_subarg_cmp("key1", "subkey1", "value1"));
 257         assert(!strncmp(ret, "value1", len));
 258
 259         ret = hwconfig_subarg("key1", "subkey2", &len);
 260         printf("%zd %.*s\n", len, (int)len, ret);
 261         assert(len == 6);
 262         assert(hwconfig_subarg_cmp("key1", "subkey2", "value2"));
 263         assert(!strncmp(ret, "value2", len));
 264
 265         ret = hwconfig_arg("key2", &len);
 266         printf("%zd %.*s\n", len, (int)len, ret);
 267         assert(len == 6);
 268         assert(hwconfig_arg_cmp("key2", "value3"));
 269         assert(!strncmp(ret, "value3", len));
 270
 271         assert(hwconfig("key3"));
 272         assert(hwconfig_arg("key4", &len) == NULL);
 273         assert(hwconfig_arg("bogus", &len) == NULL);
 274
 275         unsetenv("hwconfig");
 276
 277         assert(hwconfig(NULL) == 0);
 278         assert(hwconfig("") == 0);
 279         assert(hwconfig("key3") == 0);
 280
 281         return 0;
 282 }
 283 #endif /* HWCONFIG_TEST */