drivers/watchdog/designware_wdt.c

   1 /*
   2  * Copyright (C) 2013 Altera Corporation <www.altera.com>
   3  *
   4  * SPDX-License-Identifier:     GPL-2.0+
   5  */
   6
   7 #include <common.h>
   8 #include <watchdog.h>
   9 #include <asm/io.h>
  10 #include <asm/utils.h>
  11
  12 #define DW_WDT_CR       0x00
  13 #define DW_WDT_TORR     0x04
  14 #define DW_WDT_CRR      0x0C
  15
  16 #define DW_WDT_CR_EN_OFFSET     0x00
  17 #define DW_WDT_CR_RMOD_OFFSET   0x01
  18 #define DW_WDT_CR_RMOD_VAL      0x00
  19 #define DW_WDT_CRR_RESTART_VAL  0x76
  20
  21 /*
  22  * Set the watchdog time interval.
  23  * Counter is 32 bit.
  24  */
  25 static int designware_wdt_settimeout(unsigned int timeout)
  26 {
  27         signed int i;
  28
  29         /* calculate the timeout range value */
  30         i = (log_2_n_round_up(timeout * CONFIG_DW_WDT_CLOCK_KHZ)) - 16;
  31         if (i > 15)
  32                 i = 15;
  33         if (i < 0)
  34                 i = 0;
  35
  36         writel((i | (i << 4)), (CONFIG_DW_WDT_BASE + DW_WDT_TORR));
  37         return 0;
  38 }
  39
  40 static void designware_wdt_enable(void)
  41 {
  42         writel(((DW_WDT_CR_RMOD_VAL << DW_WDT_CR_RMOD_OFFSET) |
  43               (0x1 << DW_WDT_CR_EN_OFFSET)),
  44               (CONFIG_DW_WDT_BASE + DW_WDT_CR));
  45 }
  46
  47 static unsigned int designware_wdt_is_enabled(void)
  48 {
  49         unsigned long val;
  50         val = readl((CONFIG_DW_WDT_BASE + DW_WDT_CR));
  51         return val & 0x1;
  52 }
  53
  54 #if defined(CONFIG_HW_WATCHDOG)
  55 void hw_watchdog_reset(void)
  56 {
  57         if (designware_wdt_is_enabled())
  58                 /* restart the watchdog counter */
  59                 writel(DW_WDT_CRR_RESTART_VAL,
  60                        (CONFIG_DW_WDT_BASE + DW_WDT_CRR));
  61 }
  62
  63 void hw_watchdog_init(void)
  64 {
  65         /* reset to disable the watchdog */
  66         hw_watchdog_reset();
  67         /* set timer in miliseconds */
  68         designware_wdt_settimeout(CONFIG_WATCHDOG_TIMEOUT_MSECS);
  69         /* enable the watchdog */
  70         designware_wdt_enable();
  71         /* reset the watchdog */
  72         hw_watchdog_reset();
  73 }
  74 #endif