Merge branch 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...
[platform/kernel/linux-rpi.git] / drivers / watchdog / ep93xx_wdt.c
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
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
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
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
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");