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_device.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
23 struct xgene_reboot_context {
24 struct device *dev;
25 void *csr;
26 u32 mask;
27 struct notifier_block restart_handler;
28 };
29
xgene_restart_handler(struct notifier_block * this,unsigned long mode,void * cmd)30 static 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
xgene_reboot_probe(struct platform_device * pdev)47 static 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
78 static const struct of_device_id xgene_reboot_of_match[] = {
79 { .compatible = "apm,xgene-reboot" },
80 {}
81 };
82
83 static 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
xgene_reboot_init(void)91 static int __init xgene_reboot_init(void)
92 {
93 return platform_driver_register(&xgene_reboot_driver);
94 }
95 device_initcall(xgene_reboot_init);
96