common/hwconfig.c

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