src/vendorcode/google/chromeos/vpd_mac.c

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2
   3 #include <boot/coreboot_tables.h>
   4 #include <console/console.h>
   5 #include <ctype.h>
   6 #include <string.h>
   7
   8 #include <drivers/vpd/vpd.h>
   9
  10 /*
  11  * Decode string representation of the MAC address (a string of 12 hex
  12  * symbols) into binary. 'key_name' is the name of the VPD field, it's used if
  13  * it is necessary to report an input data format problem.
  14  */
  15 static void decode_mac(struct mac_address *mac,
  16                        const char *mac_addr_str,
  17                        const char *key_name)
  18 {
  19         int i;
  20
  21         for (i = 0; i < sizeof(mac->mac_addr); i++) {
  22                 int j;
  23                 uint8_t n = 0;
  24
  25                 for (j = 0; j < 2; j++) {
  26                         char c = mac_addr_str[i * 2 + j];
  27
  28                         if (isxdigit(c)) {
  29                                 if (isdigit(c))
  30                                         c -= '0';
  31                                 else
  32                                         c = tolower(c) - 'a' + 10;
  33                         } else {
  34                                 printk(BIOS_ERR, "%s: non hexadecimal symbol "
  35                                        "%#2.2x in the VPD field %s:%s\n",
  36                                        __func__, (uint8_t)c, key_name,
  37                                        mac_addr_str);
  38                                 c = 0;
  39                         }
  40                         n <<= 4;
  41                         n |= c;
  42                 }
  43                 mac->mac_addr[i] = n;
  44         }
  45 }
  46
  47 void lb_table_add_macs_from_vpd(struct lb_header *header)
  48 {
  49         /*
  50          * Mac addresses in the VPD can be stored in two groups, for ethernet
  51          * and WiFi, with keys 'ethernet_macX and wifi_macX.
  52          */
  53         const char *mac_addr_key_bases[] = {"ethernet_mac0", "wifi_mac0"};
  54         char mac_addr_key[20]; /* large enough for either key */
  55         char mac_addr_str[13]; /* 12 symbols and the trailing zero. */
  56         int i, count;
  57         struct lb_macs *macs = NULL;
  58
  59         /* Make sure the copy is always zero terminated. */
  60         mac_addr_key[sizeof(mac_addr_key) - 1] = '\0';
  61
  62         count = 0;
  63         for (i = 0; i < ARRAY_SIZE(mac_addr_key_bases); i++) {
  64                 int index_of_index;
  65
  66                 strncpy(mac_addr_key, mac_addr_key_bases[i],
  67                         sizeof(mac_addr_key) - 1);
  68                 index_of_index = strlen(mac_addr_key) - 1;
  69
  70                 do {
  71                         /*
  72                          * If there are no more MAC addresses of this template
  73                          * in the VPD - move on.
  74                          */
  75                         if (!vpd_gets(mac_addr_key, mac_addr_str,
  76                                            sizeof(mac_addr_str), VPD_RO_THEN_RW))
  77                                 break;
  78
  79                         if (!macs) {
  80                                 macs = (struct lb_macs *)lb_new_record(header);
  81                                 macs->tag = LB_TAG_MAC_ADDRS;
  82                         }
  83
  84                         decode_mac(macs->mac_addrs + count,
  85                                    mac_addr_str,
  86                                    mac_addr_key);
  87
  88                         count++;
  89                         mac_addr_key[index_of_index]++;
  90                 } while (count < 10);
  91         }
  92         if (!count)
  93                 return; /* No MAC addresses in the VPD. */
  94
  95         macs->count = count;
  96         macs->size = sizeof(*macs) + count * sizeof(struct mac_address);
  97 }