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(val: ctx->mask, addr: 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, size: sizeof(*ctx), GFP_KERNEL);
50 if (!ctx)
51 return -ENOMEM;
52
53 ctx->csr = devm_platform_ioremap_resource(pdev, index: 0);
54 if (IS_ERR(ptr: ctx->csr)) {
55 dev_err(dev, "can not map resource\n");
56 return PTR_ERR(ptr: ctx->csr);
57 }
58
59 if (of_property_read_u32(np: dev->of_node, propname: "mask", out_value: &ctx->mask))
60 ctx->mask = 0xFFFFFFFF;
61
62 ctx->dev = dev;
63 err = devm_register_sys_off_handler(dev, mode: SYS_OFF_MODE_RESTART, priority: 128,
64 callback: xgene_restart_handler, cb_data: 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

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