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         /* Make sure the data is written to RAM */
  39         flush_dcache_range((ulong)&save_addr[0],
  40                            (((ulong)&save_addr[REPEAT_PATTERN + OFFS_PATTERN] &
  41                              ~(ARCH_DMA_MINALIGN - 1)) + ARCH_DMA_MINALIGN));
  42 }
  43
  44 ulong bootcount_load(void)
  45 {
  46         ulong *save_addr;
  47         ulong size = 0;
  48         ulong counter = 0;
  49         int i, tmp;
  50
  51         for (i = 0; i < CONFIG_NR_DRAM_BANKS; i++)
  52                 size += gd->bd->bi_dram[i].size;
  53         save_addr = (ulong *)(size - BOOTCOUNT_ADDR);
  54
  55         counter = readl(&save_addr[0]);
  56
  57         /* Is the counter reliable, check in the big pattern for bit errors */
  58         for (i = 0; (i < REPEAT_PATTERN) && (counter != 0); i++) {
  59                 tmp = readl(&save_addr[i + OFFS_PATTERN]);
  60                 if (tmp != patterns[i % NBR_OF_PATTERNS])
  61                         counter = 0;
  62         }
  63         return counter;
  64 }