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 __iomem *csr;
26	u32 mask;
27};
28
29static int xgene_restart_handler(struct sys_off_data *data)
30{
31	struct xgene_reboot_context *ctx = data->cb_data;
32
33	/* Issue the reboot */
34	writel(ctx->mask, ctx->csr);
35
36	mdelay(1000);
37
38	dev_emerg(ctx->dev, "Unable to restart system\n");
39
40	return NOTIFY_DONE;
41}
42
43static int xgene_reboot_probe(struct platform_device *pdev)
44{
45	struct xgene_reboot_context *ctx;
46	struct device *dev = &pdev->dev;
47	int err;
48
49	ctx = devm_kzalloc(dev, sizeof(*ctx), GFP_KERNEL);
50	if (!ctx)
51		return -ENOMEM;
52
53	ctx->csr = devm_platform_ioremap_resource(pdev, 0);
54	if (IS_ERR(ctx->csr)) {
55		dev_err(dev, "can not map resource\n");
56		return PTR_ERR(ctx->csr);
57	}
58
59	if (of_property_read_u32(dev->of_node, "mask", &ctx->mask))
60		ctx->mask = 0xFFFFFFFF;
61
62	ctx->dev = dev;
63	err = devm_register_sys_off_handler(dev, SYS_OFF_MODE_RESTART, 128,
64					    xgene_restart_handler, ctx);
65	if (err)
66		dev_err(dev, "cannot register restart handler (err=%d)\n", err);
67
68	return err;
69}
70
71static const struct of_device_id xgene_reboot_of_match[] = {
72	{ .compatible = "apm,xgene-reboot" },
73	{}
74};
75
76static struct platform_driver xgene_reboot_driver = {
77	.probe = xgene_reboot_probe,
78	.driver = {
79		.name = "xgene-reboot",
80		.of_match_table = xgene_reboot_of_match,
81	},
82};
83builtin_platform_driver(xgene_reboot_driver);
84