drivers/bootcount/bootcount_ram.c

   1 /*
   2  * (C) Copyright 2010
   3  * Heiko Schocher, DENX Software Engineering, hs@denx.de.
   4  *
   5  * SPDX-License-Identifier:     GPL-2.0+
   6  */
   7
   8 #include <common.h>
   9 #include <asm/io.h>
  10
  11 DECLARE_GLOBAL_DATA_PTR;
  12
  13 const ulong patterns[]      = { 0x00000000,
  14                                 0xFFFFFFFF,
  15                                 0xFF00FF00,
  16                                 0x0F0F0F0F,
  17                                 0xF0F0F0F0};
  18 const ulong NBR_OF_PATTERNS = sizeof(patterns) / sizeof(*patterns);
  19 const ulong OFFS_PATTERN    = 3;
  20 const ulong REPEAT_PATTERN  = 1000;
  21
  22 void bootcount_store(ulong a)
  23 {
  24         ulong *save_addr;
  25         ulong size = 0;
  26         int i;
  27
  28         for (i = 0; i < CONFIG_NR_DRAM_BANKS; i++)
  29                 size += gd->bd->bi_dram[i].size;
  30         save_addr = (ulong *)(size - BOOTCOUNT_ADDR);
  31         writel(a, save_addr);
  32         writel(BOOTCOUNT_MAGIC, &save_addr[1]);
  33
  34         for (i = 0; i < REPEAT_PATTERN; i++)
  35                 writel(patterns[i % NBR_OF_PATTERNS],
  36                         &save_addr[i + OFFS_PATTERN]);
  37
  38 }
  39
  40 ulong bootcount_load(void)
  41 {
  42         ulong *save_addr;
  43         ulong size = 0;
  44         ulong counter = 0;
  45         int i, tmp;
  46
  47         for (i = 0; i < CONFIG_NR_DRAM_BANKS; i++)
  48                 size += gd->bd->bi_dram[i].size;
  49         save_addr = (ulong *)(size - BOOTCOUNT_ADDR);
  50
  51         counter = readl(&save_addr[0]);
  52
  53         /* Is the counter reliable, check in the big pattern for bit errors */
  54         for (i = 0; (i < REPEAT_PATTERN) && (counter != 0); i++) {
  55                 tmp = readl(&save_addr[i + OFFS_PATTERN]);
  56                 if (tmp != patterns[i % NBR_OF_PATTERNS])
  57                         counter = 0;
  58         }
  59         return counter;
  60 }