drivers/power/reset/zx-reboot.c

   1 /*
   2  * ZTE zx296702 SoC reset code
   3  *
   4  * Copyright (c) 2015 Linaro Ltd.
   5  *
   6  * Author: Jun Nie <jun.nie@linaro.org>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  */
  12
  13 #include <linux/delay.h>
  14 #include <linux/io.h>
  15 #include <linux/module.h>
  16 #include <linux/notifier.h>
  17 #include <linux/of_address.h>
  18 #include <linux/platform_device.h>
  19 #include <linux/reboot.h>
  20
  21 static void __iomem *base;
  22 static void __iomem *pcu_base;
  23
  24 static int zx_restart_handler(struct notifier_block *this,
  25                               unsigned long mode, void *cmd)
  26 {
  27         writel_relaxed(1, base + 0xb0);
  28         writel_relaxed(1, pcu_base + 0x34);
  29
  30         mdelay(50);
  31         pr_emerg("Unable to restart system\n");
  32
  33         return NOTIFY_DONE;
  34 }
  35
  36 static struct notifier_block zx_restart_nb = {
  37         .notifier_call = zx_restart_handler,
  38         .priority = 128,
  39 };
  40
  41 static int zx_reboot_probe(struct platform_device *pdev)
  42 {
  43         struct device_node *np = pdev->dev.of_node;
  44         int err;
  45
  46         base = of_iomap(np, 0);
  47         if (!base) {
  48                 WARN(1, "failed to map base address");
  49                 return -ENODEV;
  50         }
  51
  52         np = of_find_compatible_node(NULL, NULL, "zte,zx296702-pcu");
  53         pcu_base = of_iomap(np, 0);
  54         of_node_put(np);
  55         if (!pcu_base) {
  56                 iounmap(base);
  57                 WARN(1, "failed to map pcu_base address");
  58                 return -ENODEV;
  59         }
  60
  61         err = register_restart_handler(&zx_restart_nb);
  62         if (err) {
  63                 iounmap(base);
  64                 iounmap(pcu_base);
  65                 dev_err(&pdev->dev, "Register restart handler failed(err=%d)\n",
  66                         err);
  67         }
  68
  69         return err;
  70 }
  71
  72 static const struct of_device_id zx_reboot_of_match[] = {
  73         { .compatible = "zte,sysctrl" },
  74         {}
  75 };
  76 MODULE_DEVICE_TABLE(of, zx_reboot_of_match);
  77
  78 static struct platform_driver zx_reboot_driver = {
  79         .probe = zx_reboot_probe,
  80         .driver = {
  81                 .name = "zx-reboot",
  82                 .of_match_table = zx_reboot_of_match,
  83         },
  84 };
  85 module_platform_driver(zx_reboot_driver);
  86
  87 MODULE_DESCRIPTION("ZTE SoCs reset driver");
  88 MODULE_AUTHOR("Jun Nie <jun.nie@linaro.org>");
  89 MODULE_LICENSE("GPL v2");