src/mainboard/prodrive/atlas/vpd.c

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2
   3 #include <console/console.h>
   4 #include <stdio.h>
   5 #include <string.h>
   6 #include <types.h>
   7
   8 #include "ec.h"
   9 #include "mainboard.h"
  10 #include "vpd.h"
  11
  12 static void write_invalid_str(char *dest, size_t length)
  13 {
  14         snprintf(dest, length, "%s", "INVALID");
  15 }
  16
  17 const struct emi_eeprom_vpd *get_emi_eeprom_vpd(void)
  18 {
  19         static union {
  20                 struct emi_eeprom_vpd layout;
  21                 uint8_t raw[sizeof(struct emi_eeprom_vpd)];
  22         } vpd = {0};
  23
  24         /* Check if cached VPD is valid */
  25         if (vpd.layout.header.revision == VPD_LATEST_REVISION)
  26                 return &vpd.layout;
  27
  28         ec_emi_read(vpd.raw, EMI_0_IO_BASE_ADDR, 0, 0, sizeof(vpd.raw));
  29
  30         /* If the magic value doesn't match, consider EEPROM VPD unreliable */
  31         if (vpd.layout.header.magic != VPD_MAGIC) {
  32                 printk(BIOS_WARNING, "Atlas VPD: Bad magic value, using fallback defaults\n");
  33                 vpd.layout.header.revision = 0;
  34         } else {
  35                 printk(BIOS_DEBUG, "Atlas VPD: Got revision %u from EC\n",
  36                                 vpd.layout.header.revision);
  37         }
  38
  39         /*
  40          * For backwards compatibility, if the VPD from the EC is an older
  41          * version, uprev it to the latest version coreboot knows about by
  42          * filling in the remaining fields with default values. Should the
  43          * EC provide a newer VPD revision, coreboot would downgrade it to
  44          * the latest version it knows about as the VPD layout is designed
  45          * to be backwards compatible.
  46          *
  47          * Whenever the value of `VPD_LATEST_REVISION` is incremented, add
  48          * a new `case` label just before the `default` label that matches
  49          * the second latest revision to initialise the newly-added fields
  50          * of the VPD structure with a reasonable fallback value. Note the
  51          * intentional falling through.
  52          */
  53         switch (vpd.layout.header.revision) {
  54         case 0:
  55                 memset(vpd.raw, 0, sizeof(vpd.raw));
  56                 vpd.layout.header.magic = VPD_MAGIC;
  57                 write_invalid_str(vpd.layout.serial_number, sizeof(vpd.layout.serial_number));
  58                 write_invalid_str(vpd.layout.part_number, sizeof(vpd.layout.part_number));
  59                 vpd.layout.profile = ATLAS_PROF_UNPROGRAMMED;
  60                 __fallthrough;
  61         default:
  62                 /* Ensure serial numbers are NULL-terminated, update revision last */
  63                 vpd.layout.serial_number[ATLAS_SN_PN_LENGTH - 1] = '\0';
  64                 vpd.layout.part_number[ATLAS_SN_PN_LENGTH - 1] = '\0';
  65                 vpd.layout.header.revision = VPD_LATEST_REVISION;
  66                 break;
  67         }
  68
  69         return &vpd.layout;
  70 }