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