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
37struct xgene_reboot_context {
38	struct device *dev;
39	void *csr;
40	u32 mask;
41	struct notifier_block restart_handler;
42};
43
44static 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
61static 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		dev_err(dev, "cannot register restart handler (err=%d)\n", err);
86
87	return err;
88}
89
90static const struct of_device_id xgene_reboot_of_match[] = {
91	{ .compatible = "apm,xgene-reboot" },
92	{}
93};
94
95static struct platform_driver xgene_reboot_driver = {
96	.probe = xgene_reboot_probe,
97	.driver = {
98		.name = "xgene-reboot",
99		.of_match_table = xgene_reboot_of_match,
100	},
101};
102
103static int __init xgene_reboot_init(void)
104{
105	return platform_driver_register(&xgene_reboot_driver);
106}
107device_initcall(xgene_reboot_init);
108