1 /*
2  * AppliedMicro X-Gene SoC Reboot Driver
3  *
4  * Copyright (c) 2013, Applied Micro Circuits Corporation
5  * Author: Feng Kan <fkan@apm.com>
6  * Author: Loc Ho <lho@apm.com>
7  *
8  * This program is free software; you can redistribute it and/or
9  * modify it under the terms of the GNU General Public License as
10  * published by the Free Software Foundation; either version 2 of
11  * the License, or (at your option) any later version.
12  *
13  * This program is distributed in the hope that it will be useful,
14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16  * GNU General Public License for more details.
17  *
18  * You should have received a copy of the GNU General Public License
19  * along with this program; if not, write to the Free Software
20  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
21  * MA 02111-1307 USA
22  *
23  * This driver provides system reboot functionality for APM X-Gene SoC.
24  * For system shutdown, this is board specify. If a board designer
25  * implements GPIO shutdown, use the gpio-poweroff.c driver.
26  */
27 #include <linux/delay.h>
28 #include <linux/io.h>
29 #include <linux/notifier.h>
30 #include <linux/of_device.h>
31 #include <linux/of_address.h>
32 #include <linux/platform_device.h>
33 #include <linux/reboot.h>
34 #include <linux/stat.h>
35 #include <linux/slab.h>
36 
37 struct xgene_reboot_context {
38 	struct device *dev;
39 	void *csr;
40 	u32 mask;
41 	struct notifier_block restart_handler;
42 };
43 
44 static int xgene_restart_handler(struct notifier_block *this,
45 				 unsigned long mode, void *cmd)
46 {
47 	struct xgene_reboot_context *ctx =
48 		container_of(this, struct xgene_reboot_context,
49 			     restart_handler);
50 
51 	/* Issue the reboot */
52 	writel(ctx->mask, ctx->csr);
53 
54 	mdelay(1000);
55 
56 	dev_emerg(ctx->dev, "Unable to restart system\n");
57 
58 	return NOTIFY_DONE;
59 }
60 
61 static int xgene_reboot_probe(struct platform_device *pdev)
62 {
63 	struct xgene_reboot_context *ctx;
64 	struct device *dev = &pdev->dev;
65 	int err;
66 
67 	ctx = devm_kzalloc(dev, sizeof(*ctx), GFP_KERNEL);
68 	if (!ctx)
69 		return -ENOMEM;
70 
71 	ctx->csr = of_iomap(dev->of_node, 0);
72 	if (!ctx->csr) {
73 		dev_err(dev, "can not map resource\n");
74 		return -ENODEV;
75 	}
76 
77 	if (of_property_read_u32(dev->of_node, "mask", &ctx->mask))
78 		ctx->mask = 0xFFFFFFFF;
79 
80 	ctx->dev = dev;
81 	ctx->restart_handler.notifier_call = xgene_restart_handler;
82 	ctx->restart_handler.priority = 128;
83 	err = register_restart_handler(&ctx->restart_handler);
84 	if (err) {
85 		iounmap(ctx->csr);
86 		dev_err(dev, "cannot register restart handler (err=%d)\n", err);
87 	}
88 
89 	return err;
90 }
91 
92 static const struct of_device_id xgene_reboot_of_match[] = {
93 	{ .compatible = "apm,xgene-reboot" },
94 	{}
95 };
96 
97 static struct platform_driver xgene_reboot_driver = {
98 	.probe = xgene_reboot_probe,
99 	.driver = {
100 		.name = "xgene-reboot",
101 		.of_match_table = xgene_reboot_of_match,
102 	},
103 };
104 
105 static int __init xgene_reboot_init(void)
106 {
107 	return platform_driver_register(&xgene_reboot_driver);
108 }
109 device_initcall(xgene_reboot_init);
110