1 /*
2 * Watchdog driver for Cirrus Logic EP93xx family of devices.
3 *
4 * Copyright (c) 2004 Ray Lehtiniemi
5 * Copyright (c) 2006 Tower Technologies
6 * Based on ep93xx driver, bits from alim7101_wdt.c
7 *
8 * Authors: Ray Lehtiniemi <rayl@mail.com>,
9 * Alessandro Zummo <a.zummo@towertech.it>
10 *
11 * Copyright (c) 2012 H Hartley Sweeten <hsweeten@visionengravers.com>
12 * Convert to a platform device and use the watchdog framework API
13 *
14 * This file is licensed under the terms of the GNU General Public
15 * License version 2. This program is licensed "as is" without any
16 * warranty of any kind, whether express or implied.
17 *
18 * This watchdog fires after 250msec, which is a too short interval
19 * for us to rely on the user space daemon alone. So we ping the
20 * wdt each ~200msec and eventually stop doing it if the user space
21 * daemon dies.
22 */
23
24 #include <linux/platform_device.h>
25 #include <linux/module.h>
26 #include <linux/watchdog.h>
27 #include <linux/io.h>
28
29 /* default timeout (secs) */
30 #define WDT_TIMEOUT 30
31
32 static bool nowayout = WATCHDOG_NOWAYOUT;
33 module_param(nowayout, bool, 0);
34 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
35
36 static unsigned int timeout;
37 module_param(timeout, uint, 0);
38 MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds.");
39
40 #define EP93XX_WATCHDOG 0x00
41 #define EP93XX_WDSTATUS 0x04
42
43 struct ep93xx_wdt_priv {
44 void __iomem *mmio;
45 struct watchdog_device wdd;
46 };
47
ep93xx_wdt_start(struct watchdog_device * wdd)48 static int ep93xx_wdt_start(struct watchdog_device *wdd)
49 {
50 struct ep93xx_wdt_priv *priv = watchdog_get_drvdata(wdd);
51
52 writel(0xaaaa, priv->mmio + EP93XX_WATCHDOG);
53
54 return 0;
55 }
56
ep93xx_wdt_stop(struct watchdog_device * wdd)57 static int ep93xx_wdt_stop(struct watchdog_device *wdd)
58 {
59 struct ep93xx_wdt_priv *priv = watchdog_get_drvdata(wdd);
60
61 writel(0xaa55, priv->mmio + EP93XX_WATCHDOG);
62
63 return 0;
64 }
65
ep93xx_wdt_ping(struct watchdog_device * wdd)66 static int ep93xx_wdt_ping(struct watchdog_device *wdd)
67 {
68 struct ep93xx_wdt_priv *priv = watchdog_get_drvdata(wdd);
69
70 writel(0x5555, priv->mmio + EP93XX_WATCHDOG);
71
72 return 0;
73 }
74
75 static const struct watchdog_info ep93xx_wdt_ident = {
76 .options = WDIOF_CARDRESET |
77 WDIOF_SETTIMEOUT |
78 WDIOF_MAGICCLOSE |
79 WDIOF_KEEPALIVEPING,
80 .identity = "EP93xx Watchdog",
81 };
82
83 static const struct watchdog_ops ep93xx_wdt_ops = {
84 .owner = THIS_MODULE,
85 .start = ep93xx_wdt_start,
86 .stop = ep93xx_wdt_stop,
87 .ping = ep93xx_wdt_ping,
88 };
89
ep93xx_wdt_probe(struct platform_device * pdev)90 static int ep93xx_wdt_probe(struct platform_device *pdev)
91 {
92 struct device *dev = &pdev->dev;
93 struct ep93xx_wdt_priv *priv;
94 struct watchdog_device *wdd;
95 unsigned long val;
96 int ret;
97
98 priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
99 if (!priv)
100 return -ENOMEM;
101
102 priv->mmio = devm_platform_ioremap_resource(pdev, 0);
103 if (IS_ERR(priv->mmio))
104 return PTR_ERR(priv->mmio);
105
106 val = readl(priv->mmio + EP93XX_WATCHDOG);
107
108 wdd = &priv->wdd;
109 wdd->bootstatus = (val & 0x01) ? WDIOF_CARDRESET : 0;
110 wdd->info = &ep93xx_wdt_ident;
111 wdd->ops = &ep93xx_wdt_ops;
112 wdd->min_timeout = 1;
113 wdd->max_hw_heartbeat_ms = 200;
114 wdd->parent = dev;
115
116 watchdog_set_nowayout(wdd, nowayout);
117
118 wdd->timeout = WDT_TIMEOUT;
119 watchdog_init_timeout(wdd, timeout, dev);
120
121 watchdog_set_drvdata(wdd, priv);
122
123 ret = devm_watchdog_register_device(dev, wdd);
124 if (ret)
125 return ret;
126
127 dev_info(dev, "EP93XX watchdog driver %s\n",
128 (val & 0x08) ? " (nCS1 disable detected)" : "");
129
130 return 0;
131 }
132
133 static struct platform_driver ep93xx_wdt_driver = {
134 .driver = {
135 .name = "ep93xx-wdt",
136 },
137 .probe = ep93xx_wdt_probe,
138 };
139
140 module_platform_driver(ep93xx_wdt_driver);
141
142 MODULE_AUTHOR("Ray Lehtiniemi <rayl@mail.com>");
143 MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
144 MODULE_AUTHOR("H Hartley Sweeten <hsweeten@visionengravers.com>");
145 MODULE_DESCRIPTION("EP93xx Watchdog");
146 MODULE_LICENSE("GPL");
147