drivers/bootcount/bootcount_i2c.c

   1 /*
   2  * (C) Copyright 2013
   3  * Heiko Schocher, DENX Software Engineering, hs@denx.de.
   4  *
   5  * SPDX-License-Identifier:     GPL-2.0+
   6  */
   7
   8 #include <bootcount.h>
   9 #include <linux/compiler.h>
  10 #include <i2c.h>
  11
  12 #define BC_MAGIC        0xbc
  13
  14 void bootcount_store(ulong a)
  15 {
  16         unsigned char buf[3];
  17         int ret;
  18
  19         buf[0] = BC_MAGIC;
  20         buf[1] = (a & 0xff);
  21         ret = i2c_write(CONFIG_SYS_I2C_RTC_ADDR, CONFIG_SYS_BOOTCOUNT_ADDR,
  22                   CONFIG_BOOTCOUNT_ALEN, buf, 2);
  23         if (ret != 0)
  24                 puts("Error writing bootcount\n");
  25 }
  26
  27 ulong bootcount_load(void)
  28 {
  29         unsigned char buf[3];
  30         int ret;
  31
  32         ret = i2c_read(CONFIG_SYS_I2C_RTC_ADDR, CONFIG_SYS_BOOTCOUNT_ADDR,
  33                        CONFIG_BOOTCOUNT_ALEN, buf, 2);
  34         if (ret != 0) {
  35                 puts("Error loading bootcount\n");
  36                 return 0;
  37         }
  38         if (buf[0] == BC_MAGIC)
  39                 return buf[1];
  40
  41         bootcount_store(0);
  42
  43         return 0;
  44 }