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(val: ctx->mask, addr: 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, size: sizeof(*ctx), GFP_KERNEL);
54 if (!ctx)
55 return -ENOMEM;
56
57 ctx->csr = of_iomap(node: dev->of_node, index: 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(np: dev->of_node, propname: "mask", out_value: &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(addr: 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};
90builtin_platform_driver(xgene_reboot_driver);
91

source code of linux/drivers/power/reset/xgene-reboot.c