drivers/bootcount/bootcount_ram.c

   1 /*
   2  * (C) Copyright 2010
   3  * Heiko Schocher, DENX Software Engineering, hs@denx.de.
   4  *
   5  * See file CREDITS for list of people who contributed to this
   6  * project.
   7  *
   8  * This program is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU General Public License as
  10  * published by the Free Software Foundation; either version 2 of
  11  * the License, or (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  */
  19
  20 #include <common.h>
  21 #include <asm/io.h>
  22
  23 DECLARE_GLOBAL_DATA_PTR;
  24
  25 const ulong patterns[]      = { 0x00000000,
  26                                 0xFFFFFFFF,
  27                                 0xFF00FF00,
  28                                 0x0F0F0F0F,
  29                                 0xF0F0F0F0};
  30 const ulong NBR_OF_PATTERNS = sizeof(patterns) / sizeof(*patterns);
  31 const ulong OFFS_PATTERN    = 3;
  32 const ulong REPEAT_PATTERN  = 1000;
  33
  34 void bootcount_store(ulong a)
  35 {
  36         ulong *save_addr;
  37         ulong size = 0;
  38         int i;
  39
  40         for (i = 0; i < CONFIG_NR_DRAM_BANKS; i++)
  41                 size += gd->bd->bi_dram[i].size;
  42         save_addr = (ulong *)(size - BOOTCOUNT_ADDR);
  43         writel(a, save_addr);
  44         writel(BOOTCOUNT_MAGIC, &save_addr[1]);
  45
  46         for (i = 0; i < REPEAT_PATTERN; i++)
  47                 writel(patterns[i % NBR_OF_PATTERNS],
  48                         &save_addr[i + OFFS_PATTERN]);
  49
  50 }
  51
  52 ulong bootcount_load(void)
  53 {
  54         ulong *save_addr;
  55         ulong size = 0;
  56         ulong counter = 0;
  57         int i, tmp;
  58
  59         for (i = 0; i < CONFIG_NR_DRAM_BANKS; i++)
  60                 size += gd->bd->bi_dram[i].size;
  61         save_addr = (ulong *)(size - BOOTCOUNT_ADDR);
  62
  63         counter = readl(&save_addr[0]);
  64
  65         /* Is the counter reliable, check in the big pattern for bit errors */
  66         for (i = 0; (i < REPEAT_PATTERN) && (counter != 0); i++) {
  67                 tmp = readl(&save_addr[i + OFFS_PATTERN]);
  68                 if (tmp != patterns[i % NBR_OF_PATTERNS])
  69                         counter = 0;
  70         }
  71         return counter;
  72 }