summaryrefslogtreecommitdiff
path: root/drivers/watchdog/txx9wdt.c
blob: 88f23c5cfddba5cf646d6adb4de5c4bccd1b9bb4 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
/*
 * txx9wdt: A Hardware Watchdog Driver for TXx9 SoCs
 *
 * Copyright (C) 2007 Atsushi Nemoto <anemo@mba.ocn.ne.jp>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/types.h>
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/clk.h>
#include <linux/err.h>
#include <linux/io.h>
#include <asm/txx9tmr.h>

#define WD_TIMER_CCD	7		/* 1/256 */
#define WD_TIMER_CLK	(clk_get_rate(txx9_imclk) / (2 << WD_TIMER_CCD))
#define WD_MAX_TIMEOUT	((0xffffffff >> (32 - TXX9_TIMER_BITS)) / WD_TIMER_CLK)
#define TIMER_MARGIN	60		/* Default is 60 seconds */

static unsigned int timeout = TIMER_MARGIN;	/* in seconds */
module_param(timeout, uint, 0);
MODULE_PARM_DESC(timeout,
	"Watchdog timeout in seconds. "
	"(0<timeout<((2^" __MODULE_STRING(TXX9_TIMER_BITS) ")/(IMCLK/256)), "
	"default=" __MODULE_STRING(TIMER_MARGIN) ")");

static bool nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, bool, 0);
MODULE_PARM_DESC(nowayout,
	"Watchdog cannot be stopped once started "
	"(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");

static struct txx9_tmr_reg __iomem *txx9wdt_reg;
static struct clk *txx9_imclk;
static DEFINE_SPINLOCK(txx9_lock);

static int txx9wdt_ping(struct watchdog_device *wdt_dev)
{
	spin_lock(&txx9_lock);
	__raw_writel(TXx9_TMWTMR_TWIE | TXx9_TMWTMR_TWC, &txx9wdt_reg->wtmr);
	spin_unlock(&txx9_lock);
	return 0;
}

static int txx9wdt_start(struct watchdog_device *wdt_dev)
{
	spin_lock(&txx9_lock);
	__raw_writel(WD_TIMER_CLK * wdt_dev->timeout, &txx9wdt_reg->cpra);
	__raw_writel(WD_TIMER_CCD, &txx9wdt_reg->ccdr);
	__raw_writel(0, &txx9wdt_reg->tisr);	/* clear pending interrupt */
	__raw_writel(TXx9_TMTCR_TCE | TXx9_TMTCR_CCDE | TXx9_TMTCR_TMODE_WDOG,
		     &txx9wdt_reg->tcr);
	__raw_writel(TXx9_TMWTMR_TWIE | TXx9_TMWTMR_TWC, &txx9wdt_reg->wtmr);
	spin_unlock(&txx9_lock);
	return 0;
}

static int txx9wdt_stop(struct watchdog_device *wdt_dev)
{
	spin_lock(&txx9_lock);
	__raw_writel(TXx9_TMWTMR_WDIS, &txx9wdt_reg->wtmr);
	__raw_writel(__raw_readl(&txx9wdt_reg->tcr) & ~TXx9_TMTCR_TCE,
		     &txx9wdt_reg->tcr);
	spin_unlock(&txx9_lock);
	return 0;
}

static int txx9wdt_set_timeout(struct watchdog_device *wdt_dev,
			       unsigned int new_timeout)
{
	wdt_dev->timeout = new_timeout;
	txx9wdt_stop(wdt_dev);
	txx9wdt_start(wdt_dev);
	return 0;
}

static const struct watchdog_info txx9wdt_info = {
	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
	.identity = "Hardware Watchdog for TXx9",
};

static const struct watchdog_ops txx9wdt_ops = {
	.owner = THIS_MODULE,
	.start = txx9wdt_start,
	.stop = txx9wdt_stop,
	.ping = txx9wdt_ping,
	.set_timeout = txx9wdt_set_timeout,
};

static struct watchdog_device txx9wdt = {
	.info = &txx9wdt_info,
	.ops = &txx9wdt_ops,
};

static int __init txx9wdt_probe(struct platform_device *dev)
{
	struct resource *res;
	int ret;

	txx9_imclk = clk_get(NULL, "imbus_clk");
	if (IS_ERR(txx9_imclk)) {
		ret = PTR_ERR(txx9_imclk);
		txx9_imclk = NULL;
		goto exit;
	}
	ret = clk_enable(txx9_imclk);
	if (ret) {
		clk_put(txx9_imclk);
		txx9_imclk = NULL;
		goto exit;
	}

	res = platform_get_resource(dev, IORESOURCE_MEM, 0);
	txx9wdt_reg = devm_ioremap_resource(&dev->dev, res);
	if (IS_ERR(txx9wdt_reg)) {
		ret = PTR_ERR(txx9wdt_reg);
		goto exit;
	}

	if (timeout < 1 || timeout > WD_MAX_TIMEOUT)
		timeout = TIMER_MARGIN;
	txx9wdt.timeout = timeout;
	txx9wdt.min_timeout = 1;
	txx9wdt.max_timeout = WD_MAX_TIMEOUT;
	watchdog_set_nowayout(&txx9wdt, nowayout);

	ret = watchdog_register_device(&txx9wdt);
	if (ret)
		goto exit;

	pr_info("Hardware Watchdog Timer: timeout=%d sec (max %ld) (nowayout= %d)\n",
		timeout, WD_MAX_TIMEOUT, nowayout);

	return 0;
exit:
	if (txx9_imclk) {
		clk_disable(txx9_imclk);
		clk_put(txx9_imclk);
	}
	return ret;
}

static int __exit txx9wdt_remove(struct platform_device *dev)
{
	watchdog_unregister_device(&txx9wdt);
	clk_disable(txx9_imclk);
	clk_put(txx9_imclk);
	return 0;
}

static void txx9wdt_shutdown(struct platform_device *dev)
{
	txx9wdt_stop(&txx9wdt);
}

static struct platform_driver txx9wdt_driver = {
	.remove = __exit_p(txx9wdt_remove),
	.shutdown = txx9wdt_shutdown,
	.driver = {
		.name = "txx9wdt",
		.owner = THIS_MODULE,
	},
};

module_platform_driver_probe(txx9wdt_driver, txx9wdt_probe);

MODULE_DESCRIPTION("TXx9 Watchdog Driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
MODULE_ALIAS("platform:txx9wdt");