power/reset/hisi-reboot.c

0001 // SPDX-License-Identifier: GPL-2.0-only
0002 /*
0003  * HiSilicon SoC reset code
0004  *
0005  * Copyright (c) 2014 HiSilicon Ltd.
0006  * Copyright (c) 2014 Linaro Ltd.
0007  *
0008  * Author: Haojian Zhuang <haojian.zhuang@linaro.org>
0009  */
0010
0011 #include <linux/delay.h>
0012 #include <linux/io.h>
0013 #include <linux/module.h>
0014 #include <linux/notifier.h>
0015 #include <linux/of_address.h>
0016 #include <linux/platform_device.h>
0017 #include <linux/reboot.h>
0018
0019 #include <asm/proc-fns.h>
0020
0021 static void __iomem *base;
0022 static u32 reboot_offset;
0023
0024 static int hisi_restart_handler(struct notifier_block *this,
0025                 unsigned long mode, void *cmd)
0026 {
0027     writel_relaxed(0xdeadbeef, base + reboot_offset);
0028
0029     while (1)
0030         cpu_do_idle();
0031
0032     return NOTIFY_DONE;
0033 }
0034
0035 static struct notifier_block hisi_restart_nb = {
0036     .notifier_call = hisi_restart_handler,
0037     .priority = 128,
0038 };
0039
0040 static int hisi_reboot_probe(struct platform_device *pdev)
0041 {
0042     struct device_node *np = pdev->dev.of_node;
0043     int err;
0044
0045     base = of_iomap(np, 0);
0046     if (!base) {
0047         WARN(1, "failed to map base address");
0048         return -ENODEV;
0049     }
0050
0051     if (of_property_read_u32(np, "reboot-offset", &reboot_offset) < 0) {
0052         pr_err("failed to find reboot-offset property\n");
0053         iounmap(base);
0054         return -EINVAL;
0055     }
0056
0057     err = register_restart_handler(&hisi_restart_nb);
0058     if (err) {
0059         dev_err(&pdev->dev, "cannot register restart handler (err=%d)\n",
0060             err);
0061         iounmap(base);
0062     }
0063
0064     return err;
0065 }
0066
0067 static const struct of_device_id hisi_reboot_of_match[] = {
0068     { .compatible = "hisilicon,sysctrl" },
0069     {}
0070 };
0071 MODULE_DEVICE_TABLE(of, hisi_reboot_of_match);
0072
0073 static struct platform_driver hisi_reboot_driver = {
0074     .probe = hisi_reboot_probe,
0075     .driver = {
0076         .name = "hisi-reboot",
0077         .of_match_table = hisi_reboot_of_match,
0078     },
0079 };
0080 module_platform_driver(hisi_reboot_driver);