1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * AppliedMicro X-Gene SoC Reboot Driver
4 *
5 * Copyright (c) 2013, Applied Micro Circuits Corporation
6 * Author: Feng Kan <fkan@apm.com>
7 * Author: Loc Ho <lho@apm.com>
8 *
9 * This driver provides system reboot functionality for APM X-Gene SoC.
10 * For system shutdown, this is board specify. If a board designer
11 * implements GPIO shutdown, use the gpio-poweroff.c driver.
12 */
13#include <linux/delay.h>
14#include <linux/io.h>
15#include <linux/notifier.h>
16#include <linux/of.h>
17#include <linux/of_address.h>
18#include <linux/platform_device.h>
19#include <linux/reboot.h>
20#include <linux/stat.h>
21#include <linux/slab.h>
22
23struct xgene_reboot_context {
24	struct device *dev;
25	void *csr;
26	u32 mask;
27	struct notifier_block restart_handler;
28};
29
30static int xgene_restart_handler(struct notifier_block *this,
31				 unsigned long mode, void *cmd)
32{
33	struct xgene_reboot_context *ctx =
34		container_of(this, struct xgene_reboot_context,
35			     restart_handler);
36
37	/* Issue the reboot */
38	writel(ctx->mask, ctx->csr);
39
40	mdelay(1000);
41
42	dev_emerg(ctx->dev, "Unable to restart system\n");
43
44	return NOTIFY_DONE;
45}
46
47static int xgene_reboot_probe(struct platform_device *pdev)
48{
49	struct xgene_reboot_context *ctx;
50	struct device *dev = &pdev->dev;
51	int err;
52
53	ctx = devm_kzalloc(dev, sizeof(*ctx), GFP_KERNEL);
54	if (!ctx)
55		return -ENOMEM;
56
57	ctx->csr = of_iomap(dev->of_node, 0);
58	if (!ctx->csr) {
59		dev_err(dev, "can not map resource\n");
60		return -ENODEV;
61	}
62
63	if (of_property_read_u32(dev->of_node, "mask", &ctx->mask))
64		ctx->mask = 0xFFFFFFFF;
65
66	ctx->dev = dev;
67	ctx->restart_handler.notifier_call = xgene_restart_handler;
68	ctx->restart_handler.priority = 128;
69	err = register_restart_handler(&ctx->restart_handler);
70	if (err) {
71		iounmap(ctx->csr);
72		dev_err(dev, "cannot register restart handler (err=%d)\n", err);
73	}
74
75	return err;
76}
77
78static const struct of_device_id xgene_reboot_of_match[] = {
79	{ .compatible = "apm,xgene-reboot" },
80	{}
81};
82
83static struct platform_driver xgene_reboot_driver = {
84	.probe = xgene_reboot_probe,
85	.driver = {
86		.name = "xgene-reboot",
87		.of_match_table = xgene_reboot_of_match,
88	},
89};
90
91static int __init xgene_reboot_init(void)
92{
93	return platform_driver_register(&xgene_reboot_driver);
94}
95device_initcall(xgene_reboot_init);
96