drivers/power/reset/zx-reboot.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * ZTE zx296702 SoC reset code
   4  *
   5  * Copyright (c) 2015 Linaro Ltd.
   6  *
   7  * Author: Jun Nie <jun.nie@linaro.org>
   8  */
   9
  10 #include <linux/delay.h>
  11 #include <linux/io.h>
  12 #include <linux/module.h>
  13 #include <linux/notifier.h>
  14 #include <linux/of_address.h>
  15 #include <linux/platform_device.h>
  16 #include <linux/reboot.h>
  17
  18 static void __iomem *base;
  19 static void __iomem *pcu_base;
  20
  21 static int zx_restart_handler(struct notifier_block *this,
  22                               unsigned long mode, void *cmd)
  23 {
  24         writel_relaxed(1, base + 0xb0);
  25         writel_relaxed(1, pcu_base + 0x34);
  26
  27         mdelay(50);
  28         pr_emerg("Unable to restart system\n");
  29
  30         return NOTIFY_DONE;
  31 }
  32
  33 static struct notifier_block zx_restart_nb = {
  34         .notifier_call = zx_restart_handler,
  35         .priority = 128,
  36 };
  37
  38 static int zx_reboot_probe(struct platform_device *pdev)
  39 {
  40         struct device_node *np = pdev->dev.of_node;
  41         int err;
  42
  43         base = of_iomap(np, 0);
  44         if (!base) {
  45                 WARN(1, "failed to map base address");
  46                 return -ENODEV;
  47         }
  48
  49         np = of_find_compatible_node(NULL, NULL, "zte,zx296702-pcu");
  50         pcu_base = of_iomap(np, 0);
  51         of_node_put(np);
  52         if (!pcu_base) {
  53                 iounmap(base);
  54                 WARN(1, "failed to map pcu_base address");
  55                 return -ENODEV;
  56         }
  57
  58         err = register_restart_handler(&zx_restart_nb);
  59         if (err) {
  60                 iounmap(base);
  61                 iounmap(pcu_base);
  62                 dev_err(&pdev->dev, "Register restart handler failed(err=%d)\n",
  63                         err);
  64         }
  65
  66         return err;
  67 }
  68
  69 static const struct of_device_id zx_reboot_of_match[] = {
  70         { .compatible = "zte,sysctrl" },
  71         {}
  72 };
  73 MODULE_DEVICE_TABLE(of, zx_reboot_of_match);
  74
  75 static struct platform_driver zx_reboot_driver = {
  76         .probe = zx_reboot_probe,
  77         .driver = {
  78                 .name = "zx-reboot",
  79                 .of_match_table = zx_reboot_of_match,
  80         },
  81 };
  82 module_platform_driver(zx_reboot_driver);
  83
  84 MODULE_DESCRIPTION("ZTE SoCs reset driver");
  85 MODULE_AUTHOR("Jun Nie <jun.nie@linaro.org>");
  86 MODULE_LICENSE("GPL v2");