LXR linux/drivers/power/reset/hisi-reboot.c

   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * HiSilicon SoC reset code
   4 *
   5 * Copyright (c) 2014 HiSilicon Ltd.
   6 * Copyright (c) 2014 Linaro Ltd.
   7 *
   8 * Author: Haojian Zhuang <haojian.zhuang@linaro.org>
   9 */
  10
  11#include <linux/delay.h>
  12#include <linux/io.h>
  13#include <linux/module.h>
  14#include <linux/notifier.h>
  15#include <linux/of_address.h>
  16#include <linux/platform_device.h>
  17#include <linux/reboot.h>
  18
  19#include <asm/proc-fns.h>
  20
  21static void __iomem *base;
  22static u32 reboot_offset;
  23
  24static int hisi_restart_handler(struct notifier_block *this,
  25                                unsigned long mode, void *cmd)
  26{
  27        writel_relaxed(0xdeadbeef, base + reboot_offset);
  28
  29        while (1)
  30                cpu_do_idle();
  31
  32        return NOTIFY_DONE;
  33}
  34
  35static struct notifier_block hisi_restart_nb = {
  36        .notifier_call = hisi_restart_handler,
  37        .priority = 128,
  38};
  39
  40static int hisi_reboot_probe(struct platform_device *pdev)
  41{
  42        struct device_node *np = pdev->dev.of_node;
  43        int err;
  44
  45        base = of_iomap(np, 0);
  46        if (!base) {
  47                WARN(1, "failed to map base address");
  48                return -ENODEV;
  49        }
  50
  51        if (of_property_read_u32(np, "reboot-offset", &reboot_offset) < 0) {
  52                pr_err("failed to find reboot-offset property\n");
  53                iounmap(base);
  54                return -EINVAL;
  55        }
  56
  57        err = register_restart_handler(&hisi_restart_nb);
  58        if (err) {
  59                dev_err(&pdev->dev, "cannot register restart handler (err=%d)\n",
  60                        err);
  61                iounmap(base);
  62        }
  63
  64        return err;
  65}
  66
  67static const struct of_device_id hisi_reboot_of_match[] = {
  68        { .compatible = "hisilicon,sysctrl" },
  69        {}
  70};
  71MODULE_DEVICE_TABLE(of, hisi_reboot_of_match);
  72
  73static struct platform_driver hisi_reboot_driver = {
  74        .probe = hisi_reboot_probe,
  75        .driver = {
  76                .name = "hisi-reboot",
  77                .of_match_table = hisi_reboot_of_match,
  78        },
  79};
  80module_platform_driver(hisi_reboot_driver);
  81