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 21 static void __iomem *base; 22 static u32 reboot_offset; 23 24 static 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 35 static struct notifier_block hisi_restart_nb = { 36 .notifier_call = hisi_restart_handler, 37 .priority = 128, 38 }; 39 40 static 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 67 static const struct of_device_id hisi_reboot_of_match[] = { 68 { .compatible = "hisilicon,sysctrl" }, 69 {} 70 }; 71 72 static struct platform_driver hisi_reboot_driver = { 73 .probe = hisi_reboot_probe, 74 .driver = { 75 .name = "hisi-reboot", 76 .of_match_table = hisi_reboot_of_match, 77 }, 78 }; 79 module_platform_driver(hisi_reboot_driver); 80