drivers/power/reset/arm-versatile-reboot.c

   1 /*
   2  * Copyright (C) 2014 Linaro Ltd.
   3  *
   4  * Author: Linus Walleij <linus.walleij@linaro.org>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2, as
   8  * published by the Free Software Foundation.
   9  *
  10  */
  11 #include <linux/init.h>
  12 #include <linux/mfd/syscon.h>
  13 #include <linux/reboot.h>
  14 #include <linux/regmap.h>
  15 #include <linux/of.h>
  16 #include <asm/system_misc.h>
  17
  18 #define REALVIEW_SYS_LOCK_OFFSET        0x20
  19 #define REALVIEW_SYS_LOCK_VAL           0xA05F
  20 #define REALVIEW_SYS_RESETCTL_OFFSET    0x40
  21
  22 /*
  23  * We detect the different syscon types from the compatible strings.
  24  */
  25 enum versatile_reboot {
  26         REALVIEW_REBOOT_EB,
  27         REALVIEW_REBOOT_PB1176,
  28         REALVIEW_REBOOT_PB11MP,
  29         REALVIEW_REBOOT_PBA8,
  30         REALVIEW_REBOOT_PBX,
  31 };
  32
  33 /* Pointer to the system controller */
  34 static struct regmap *syscon_regmap;
  35 static enum versatile_reboot versatile_reboot_type;
  36
  37 static const struct of_device_id versatile_reboot_of_match[] = {
  38         {
  39                 .compatible = "arm,realview-eb-syscon",
  40                 .data = (void *)REALVIEW_REBOOT_EB,
  41         },
  42         {
  43                 .compatible = "arm,realview-pb1176-syscon",
  44                 .data = (void *)REALVIEW_REBOOT_PB1176,
  45         },
  46         {
  47                 .compatible = "arm,realview-pb11mp-syscon",
  48                 .data = (void *)REALVIEW_REBOOT_PB11MP,
  49         },
  50         {
  51                 .compatible = "arm,realview-pba8-syscon",
  52                 .data = (void *)REALVIEW_REBOOT_PBA8,
  53         },
  54         {
  55                 .compatible = "arm,realview-pbx-syscon",
  56                 .data = (void *)REALVIEW_REBOOT_PBX,
  57         },
  58 };
  59
  60 static void versatile_reboot(enum reboot_mode mode, const char *cmd)
  61 {
  62         /* Unlock the reset register */
  63         regmap_write(syscon_regmap, REALVIEW_SYS_LOCK_OFFSET,
  64                      REALVIEW_SYS_LOCK_VAL);
  65         /* Then hit reset on the different machines */
  66         switch (versatile_reboot_type) {
  67         case REALVIEW_REBOOT_EB:
  68                 regmap_write(syscon_regmap,
  69                              REALVIEW_SYS_RESETCTL_OFFSET, 0x0008);
  70                 break;
  71         case REALVIEW_REBOOT_PB1176:
  72                 regmap_write(syscon_regmap,
  73                              REALVIEW_SYS_RESETCTL_OFFSET, 0x0100);
  74                 break;
  75         case REALVIEW_REBOOT_PB11MP:
  76         case REALVIEW_REBOOT_PBA8:
  77                 regmap_write(syscon_regmap, REALVIEW_SYS_RESETCTL_OFFSET,
  78                              0x0000);
  79                 regmap_write(syscon_regmap, REALVIEW_SYS_RESETCTL_OFFSET,
  80                              0x0004);
  81                 break;
  82         case REALVIEW_REBOOT_PBX:
  83                 regmap_write(syscon_regmap, REALVIEW_SYS_RESETCTL_OFFSET,
  84                              0x00f0);
  85                 regmap_write(syscon_regmap, REALVIEW_SYS_RESETCTL_OFFSET,
  86                              0x00f4);
  87                 break;
  88         }
  89         dsb();
  90 }
  91
  92 static int __init versatile_reboot_probe(void)
  93 {
  94         const struct of_device_id *reboot_id;
  95         struct device_node *np;
  96
  97         np = of_find_matching_node_and_match(NULL, versatile_reboot_of_match,
  98                                                  &reboot_id);
  99         if (!np)
 100                 return -ENODEV;
 101         versatile_reboot_type = (enum versatile_reboot)reboot_id->data;
 102
 103         syscon_regmap = syscon_node_to_regmap(np);
 104         if (IS_ERR(syscon_regmap))
 105                 return PTR_ERR(syscon_regmap);
 106
 107         arm_pm_restart = versatile_reboot;
 108         pr_info("versatile reboot driver registered\n");
 109         return 0;
 110 }
 111 device_initcall(versatile_reboot_probe);