board/gateworks/gw_ventana/eeprom.c

   1 /*
   2  * Copyright (C) 2014 Gateworks Corporation
   3  * Author: Tim Harvey <tharvey@gateworks.com>
   4  *
   5  * SPDX-License-Identifier: GPL-2.0+
   6  */
   7
   8 #include <common.h>
   9 #include <i2c.h>
  10
  11 #include "gsc.h"
  12 #include "ventana_eeprom.h"
  13
  14 /* read ventana EEPROM, check for validity, and return baseboard type */
  15 int
  16 read_eeprom(int bus, struct ventana_board_info *info)
  17 {
  18         int i;
  19         int chksum;
  20         char baseboard;
  21         int type;
  22         unsigned char *buf = (unsigned char *)info;
  23
  24         memset(info, 0, sizeof(*info));
  25
  26         /*
  27          * On a board with a missing/depleted backup battery for GSC, the
  28          * board may be ready to probe the GSC before its firmware is
  29          * running.  We will wait here indefinately for the GSC/EEPROM.
  30          */
  31         while (1) {
  32                 if (0 == i2c_set_bus_num(bus) &&
  33                     0 == i2c_probe(GSC_EEPROM_ADDR))
  34                         break;
  35                 mdelay(1);
  36         }
  37
  38         /* read eeprom config section */
  39         if (gsc_i2c_read(GSC_EEPROM_ADDR, 0x00, 1, buf, sizeof(*info))) {
  40                 puts("EEPROM: Failed to read EEPROM\n");
  41                 info->model[0] = 0;
  42                 return GW_UNKNOWN;
  43         }
  44
  45         /* sanity checks */
  46         if (info->model[0] != 'G' || info->model[1] != 'W') {
  47                 puts("EEPROM: Invalid Model in EEPROM\n");
  48                 info->model[0] = 0;
  49                 return GW_UNKNOWN;
  50         }
  51
  52         /* validate checksum */
  53         for (chksum = 0, i = 0; i < sizeof(*info)-2; i++)
  54                 chksum += buf[i];
  55         if ((info->chksum[0] != chksum>>8) ||
  56             (info->chksum[1] != (chksum&0xff))) {
  57                 puts("EEPROM: Failed EEPROM checksum\n");
  58                 info->model[0] = 0;
  59                 return GW_UNKNOWN;
  60         }
  61
  62         /* original GW5400-A prototype */
  63         baseboard = info->model[3];
  64         if (strncasecmp((const char *)info->model, "GW5400-A", 8) == 0)
  65                 baseboard = '0';
  66
  67         switch (baseboard) {
  68         case '0': /* original GW5400-A prototype */
  69                 type = GW54proto;
  70                 break;
  71         case '1':
  72                 type = GW51xx;
  73                 break;
  74         case '2':
  75                 type = GW52xx;
  76                 break;
  77         case '3':
  78                 type = GW53xx;
  79                 break;
  80         case '4':
  81                 type = GW54xx;
  82                 break;
  83         default:
  84                 printf("EEPROM: Unknown model in EEPROM: %s\n", info->model);
  85                 type = GW_UNKNOWN;
  86                 break;
  87         }
  88         return type;
  89 }