File: ep93xx_wdt.c

package info (click to toggle)
linux 4.19.20-1
  • links: PTS, VCS
  • area: main
  • in suites: buster
  • size: 954,852 kB
  • sloc: ansic: 16,749,828; asm: 271,286; makefile: 38,257; sh: 32,808; perl: 27,671; python: 21,022; cpp: 5,063; yacc: 4,648; lex: 2,585; awk: 1,385; ruby: 25; sed: 5
file content (147 lines) | stat: -rw-r--r-- 3,773 bytes parent folder | download | duplicates (5)
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
/*
 * Watchdog driver for Cirrus Logic EP93xx family of devices.
 *
 * Copyright (c) 2004 Ray Lehtiniemi
 * Copyright (c) 2006 Tower Technologies
 * Based on ep93xx driver, bits from alim7101_wdt.c
 *
 * Authors: Ray Lehtiniemi <rayl@mail.com>,
 *	Alessandro Zummo <a.zummo@towertech.it>
 *
 * Copyright (c) 2012 H Hartley Sweeten <hsweeten@visionengravers.com>
 *	Convert to a platform device and use the watchdog framework API
 *
 * This file is licensed under the terms of the GNU General Public
 * License version 2. This program is licensed "as is" without any
 * warranty of any kind, whether express or implied.
 *
 * This watchdog fires after 250msec, which is a too short interval
 * for us to rely on the user space daemon alone. So we ping the
 * wdt each ~200msec and eventually stop doing it if the user space
 * daemon dies.
 */

#include <linux/platform_device.h>
#include <linux/module.h>
#include <linux/watchdog.h>
#include <linux/io.h>

/* default timeout (secs) */
#define WDT_TIMEOUT 30

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

static unsigned int timeout;
module_param(timeout, uint, 0);
MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds.");

#define EP93XX_WATCHDOG		0x00
#define EP93XX_WDSTATUS		0x04

struct ep93xx_wdt_priv {
	void __iomem *mmio;
	struct watchdog_device wdd;
};

static int ep93xx_wdt_start(struct watchdog_device *wdd)
{
	struct ep93xx_wdt_priv *priv = watchdog_get_drvdata(wdd);

	writel(0xaaaa, priv->mmio + EP93XX_WATCHDOG);

	return 0;
}

static int ep93xx_wdt_stop(struct watchdog_device *wdd)
{
	struct ep93xx_wdt_priv *priv = watchdog_get_drvdata(wdd);

	writel(0xaa55, priv->mmio + EP93XX_WATCHDOG);

	return 0;
}

static int ep93xx_wdt_ping(struct watchdog_device *wdd)
{
	struct ep93xx_wdt_priv *priv = watchdog_get_drvdata(wdd);

	writel(0x5555, priv->mmio + EP93XX_WATCHDOG);

	return 0;
}

static const struct watchdog_info ep93xx_wdt_ident = {
	.options	= WDIOF_CARDRESET |
			  WDIOF_SETTIMEOUT |
			  WDIOF_MAGICCLOSE |
			  WDIOF_KEEPALIVEPING,
	.identity	= "EP93xx Watchdog",
};

static const struct watchdog_ops ep93xx_wdt_ops = {
	.owner		= THIS_MODULE,
	.start		= ep93xx_wdt_start,
	.stop		= ep93xx_wdt_stop,
	.ping		= ep93xx_wdt_ping,
};

static int ep93xx_wdt_probe(struct platform_device *pdev)
{
	struct ep93xx_wdt_priv *priv;
	struct watchdog_device *wdd;
	struct resource *res;
	unsigned long val;
	int ret;

	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
	if (!priv)
		return -ENOMEM;

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	priv->mmio = devm_ioremap_resource(&pdev->dev, res);
	if (IS_ERR(priv->mmio))
		return PTR_ERR(priv->mmio);

	val = readl(priv->mmio + EP93XX_WATCHDOG);

	wdd = &priv->wdd;
	wdd->bootstatus = (val & 0x01) ? WDIOF_CARDRESET : 0;
	wdd->info = &ep93xx_wdt_ident;
	wdd->ops = &ep93xx_wdt_ops;
	wdd->min_timeout = 1;
	wdd->max_hw_heartbeat_ms = 200;
	wdd->parent = &pdev->dev;

	watchdog_set_nowayout(wdd, nowayout);

	wdd->timeout = WDT_TIMEOUT;
	watchdog_init_timeout(wdd, timeout, &pdev->dev);

	watchdog_set_drvdata(wdd, priv);

	ret = devm_watchdog_register_device(&pdev->dev, wdd);
	if (ret)
		return ret;

	dev_info(&pdev->dev, "EP93XX watchdog driver %s\n",
		(val & 0x08) ? " (nCS1 disable detected)" : "");

	return 0;
}

static struct platform_driver ep93xx_wdt_driver = {
	.driver		= {
		.name	= "ep93xx-wdt",
	},
	.probe		= ep93xx_wdt_probe,
};

module_platform_driver(ep93xx_wdt_driver);

MODULE_AUTHOR("Ray Lehtiniemi <rayl@mail.com>");
MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
MODULE_AUTHOR("H Hartley Sweeten <hsweeten@visionengravers.com>");
MODULE_DESCRIPTION("EP93xx Watchdog");
MODULE_LICENSE("GPL");