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