drivers/power/reset/hisi-reboot.c

   1 /*
   2  * Hisilicon SoC reset code
   3  *
   4  * Copyright (c) 2014 Hisilicon Ltd.
   5  * Copyright (c) 2014 Linaro Ltd.
   6  *
   7  * Author: Haojian Zhuang <haojian.zhuang@linaro.org>
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License version 2 as
  11  * published by the Free Software Foundation.
  12  */
  13
  14 #include <linux/delay.h>
  15 #include <linux/io.h>
  16 #include <linux/module.h>
  17 #include <linux/notifier.h>
  18 #include <linux/of_address.h>
  19 #include <linux/platform_device.h>
  20 #include <linux/reboot.h>
  21
  22 #include <asm/proc-fns.h>
  23
  24 static void __iomem *base;
  25 static u32 reboot_offset;
  26
  27 static int hisi_restart_handler(struct notifier_block *this,
  28                                 unsigned long mode, void *cmd)
  29 {
  30         writel_relaxed(0xdeadbeef, base + reboot_offset);
  31
  32         while (1)
  33                 cpu_do_idle();
  34
  35         return NOTIFY_DONE;
  36 }
  37
  38 static struct notifier_block hisi_restart_nb = {
  39         .notifier_call = hisi_restart_handler,
  40         .priority = 128,
  41 };
  42
  43 static int hisi_reboot_probe(struct platform_device *pdev)
  44 {
  45         struct device_node *np = pdev->dev.of_node;
  46         int err;
  47
  48         base = of_iomap(np, 0);
  49         if (!base) {
  50                 WARN(1, "failed to map base address");
  51                 return -ENODEV;
  52         }
  53
  54         if (of_property_read_u32(np, "reboot-offset", &reboot_offset) < 0) {
  55                 pr_err("failed to find reboot-offset property\n");
  56                 iounmap(base);
  57                 return -EINVAL;
  58         }
  59
  60         err = register_restart_handler(&hisi_restart_nb);
  61         if (err) {
  62                 dev_err(&pdev->dev, "cannot register restart handler (err=%d)\n",
  63                         err);
  64                 iounmap(base);
  65         }
  66
  67         return err;
  68 }
  69
  70 static const struct of_device_id hisi_reboot_of_match[] = {
  71         { .compatible = "hisilicon,sysctrl" },
  72         {}
  73 };
  74
  75 static struct platform_driver hisi_reboot_driver = {
  76         .probe = hisi_reboot_probe,
  77         .driver = {
  78                 .name = "hisi-reboot",
  79                 .of_match_table = hisi_reboot_of_match,
  80         },
  81 };
  82 module_platform_driver(hisi_reboot_driver);