arch/arm/mach-bcm/kona.c

   1 /*
   2  * Copyright (C) 2013 Broadcom Corporation
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public License as
   6  * published by the Free Software Foundation version 2.
   7  *
   8  * This program is distributed "as is" WITHOUT ANY WARRANTY of any
   9  * kind, whether express or implied; without even the implied warranty
  10  * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  */
  13
  14 #include <linux/of_address.h>
  15 #include <asm/io.h>
  16
  17 #include "kona.h"
  18
  19 static void __iomem *watchdog_base;
  20
  21 void bcm_kona_setup_restart(void)
  22 {
  23         struct device_node *np_wdog;
  24
  25         /*
  26          * The assumption is that whoever calls bcm_kona_setup_restart()
  27          * also needs a Kona Watchdog Timer entry in Device Tree, i.e. we
  28          * report an error if the DT entry is missing.
  29          */
  30         np_wdog = of_find_compatible_node(NULL, NULL, "brcm,kona-wdt");
  31         if (!np_wdog) {
  32                 pr_err("brcm,kona-wdt not found in DT, reboot disabled\n");
  33                 return;
  34         }
  35         watchdog_base = of_iomap(np_wdog, 0);
  36         WARN(!watchdog_base, "failed to map watchdog base");
  37         of_node_put(np_wdog);
  38 }
  39
  40 #define SECWDOG_OFFSET                  0x00000000
  41 #define SECWDOG_RESERVED_MASK           0xE2000000
  42 #define SECWDOG_WD_LOAD_FLAG_MASK       0x10000000
  43 #define SECWDOG_EN_MASK                 0x08000000
  44 #define SECWDOG_SRSTEN_MASK             0x04000000
  45 #define SECWDOG_CLKS_SHIFT              20
  46 #define SECWDOG_LOCK_SHIFT              0
  47
  48 void bcm_kona_restart(enum reboot_mode mode, const char *cmd)
  49 {
  50         uint32_t val;
  51
  52         if (!watchdog_base)
  53                 panic("Watchdog not mapped. Reboot failed.\n");
  54
  55         /* Enable watchdog2 with very short timeout. */
  56         val = readl(watchdog_base + SECWDOG_OFFSET);
  57         val &= SECWDOG_RESERVED_MASK | SECWDOG_WD_LOAD_FLAG_MASK;
  58         val |= SECWDOG_EN_MASK | SECWDOG_SRSTEN_MASK |
  59                 (0x8 << SECWDOG_CLKS_SHIFT) |
  60                 (0x8 << SECWDOG_LOCK_SHIFT);
  61         writel(val, watchdog_base + SECWDOG_OFFSET);
  62
  63         while (1)
  64                 ;
  65 }