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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
32static bool nowayout = WATCHDOG_NOWAYOUT;
33module_param(nowayout, bool, 0);
34MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
35
36static unsigned int timeout;
37module_param(timeout, uint, 0);
38MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds.");
39
40#define EP93XX_WATCHDOG 0x00
41#define EP93XX_WDSTATUS 0x04
42
43struct ep93xx_wdt_priv {
44 void __iomem *mmio;
45 struct watchdog_device wdd;
46};
47
48static 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
57static 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
66static 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
75static 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
83static 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
90static 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
133static struct platform_driver ep93xx_wdt_driver = {
134 .driver = {
135 .name = "ep93xx-wdt",
136 },
137 .probe = ep93xx_wdt_probe,
138};
139
140module_platform_driver(ep93xx_wdt_driver);
141
142MODULE_AUTHOR("Ray Lehtiniemi <rayl@mail.com>");
143MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
144MODULE_AUTHOR("H Hartley Sweeten <hsweeten@visionengravers.com>");
145MODULE_DESCRIPTION("EP93xx Watchdog");
146MODULE_LICENSE("GPL");
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 * This file is licensed under the terms of the GNU General Public
12 * License version 2. This program is licensed "as is" without any
13 * warranty of any kind, whether express or implied.
14 *
15 * This watchdog fires after 250msec, which is a too short interval
16 * for us to rely on the user space daemon alone. So we ping the
17 * wdt each ~200msec and eventually stop doing it if the user space
18 * daemon dies.
19 *
20 * TODO:
21 *
22 * - Test last reset from watchdog status
23 * - Add a few missing ioctls
24 */
25
26#include <linux/module.h>
27#include <linux/fs.h>
28#include <linux/miscdevice.h>
29#include <linux/watchdog.h>
30#include <linux/timer.h>
31#include <linux/uaccess.h>
32#include <linux/io.h>
33#include <mach/hardware.h>
34
35#define WDT_VERSION "0.3"
36#define PFX "ep93xx_wdt: "
37
38/* default timeout (secs) */
39#define WDT_TIMEOUT 30
40
41static int nowayout = WATCHDOG_NOWAYOUT;
42static int timeout = WDT_TIMEOUT;
43
44static struct timer_list timer;
45static unsigned long next_heartbeat;
46static unsigned long wdt_status;
47static unsigned long boot_status;
48
49#define WDT_IN_USE 0
50#define WDT_OK_TO_CLOSE 1
51
52#define EP93XX_WDT_REG(x) (EP93XX_WATCHDOG_BASE + (x))
53#define EP93XX_WDT_WATCHDOG EP93XX_WDT_REG(0x00)
54#define EP93XX_WDT_WDSTATUS EP93XX_WDT_REG(0x04)
55
56/* reset the wdt every ~200ms */
57#define WDT_INTERVAL (HZ/5)
58
59static void wdt_enable(void)
60{
61 __raw_writew(0xaaaa, EP93XX_WDT_WATCHDOG);
62}
63
64static void wdt_disable(void)
65{
66 __raw_writew(0xaa55, EP93XX_WDT_WATCHDOG);
67}
68
69static inline void wdt_ping(void)
70{
71 __raw_writew(0x5555, EP93XX_WDT_WATCHDOG);
72}
73
74static void wdt_startup(void)
75{
76 next_heartbeat = jiffies + (timeout * HZ);
77
78 wdt_enable();
79 mod_timer(&timer, jiffies + WDT_INTERVAL);
80}
81
82static void wdt_shutdown(void)
83{
84 del_timer_sync(&timer);
85 wdt_disable();
86}
87
88static void wdt_keepalive(void)
89{
90 /* user land ping */
91 next_heartbeat = jiffies + (timeout * HZ);
92}
93
94static int ep93xx_wdt_open(struct inode *inode, struct file *file)
95{
96 if (test_and_set_bit(WDT_IN_USE, &wdt_status))
97 return -EBUSY;
98
99 clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
100
101 wdt_startup();
102
103 return nonseekable_open(inode, file);
104}
105
106static ssize_t
107ep93xx_wdt_write(struct file *file, const char __user *data, size_t len,
108 loff_t *ppos)
109{
110 if (len) {
111 if (!nowayout) {
112 size_t i;
113
114 clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
115
116 for (i = 0; i != len; i++) {
117 char c;
118
119 if (get_user(c, data + i))
120 return -EFAULT;
121
122 if (c == 'V')
123 set_bit(WDT_OK_TO_CLOSE, &wdt_status);
124 else
125 clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
126 }
127 }
128 wdt_keepalive();
129 }
130
131 return len;
132}
133
134static const struct watchdog_info ident = {
135 .options = WDIOF_CARDRESET | WDIOF_MAGICCLOSE,
136 .identity = "EP93xx Watchdog",
137};
138
139static long ep93xx_wdt_ioctl(struct file *file,
140 unsigned int cmd, unsigned long arg)
141{
142 int ret = -ENOTTY;
143
144 switch (cmd) {
145 case WDIOC_GETSUPPORT:
146 ret = copy_to_user((struct watchdog_info __user *)arg, &ident,
147 sizeof(ident)) ? -EFAULT : 0;
148 break;
149
150 case WDIOC_GETSTATUS:
151 ret = put_user(0, (int __user *)arg);
152 break;
153
154 case WDIOC_GETBOOTSTATUS:
155 ret = put_user(boot_status, (int __user *)arg);
156 break;
157
158 case WDIOC_KEEPALIVE:
159 wdt_keepalive();
160 ret = 0;
161 break;
162
163 case WDIOC_GETTIMEOUT:
164 /* actually, it is 0.250 seconds.... */
165 ret = put_user(1, (int __user *)arg);
166 break;
167 }
168 return ret;
169}
170
171static int ep93xx_wdt_release(struct inode *inode, struct file *file)
172{
173 if (test_bit(WDT_OK_TO_CLOSE, &wdt_status))
174 wdt_shutdown();
175 else
176 printk(KERN_CRIT PFX
177 "Device closed unexpectedly - timer will not stop\n");
178
179 clear_bit(WDT_IN_USE, &wdt_status);
180 clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
181
182 return 0;
183}
184
185static const struct file_operations ep93xx_wdt_fops = {
186 .owner = THIS_MODULE,
187 .write = ep93xx_wdt_write,
188 .unlocked_ioctl = ep93xx_wdt_ioctl,
189 .open = ep93xx_wdt_open,
190 .release = ep93xx_wdt_release,
191 .llseek = no_llseek,
192};
193
194static struct miscdevice ep93xx_wdt_miscdev = {
195 .minor = WATCHDOG_MINOR,
196 .name = "watchdog",
197 .fops = &ep93xx_wdt_fops,
198};
199
200static void ep93xx_timer_ping(unsigned long data)
201{
202 if (time_before(jiffies, next_heartbeat))
203 wdt_ping();
204
205 /* Re-set the timer interval */
206 mod_timer(&timer, jiffies + WDT_INTERVAL);
207}
208
209static int __init ep93xx_wdt_init(void)
210{
211 int err;
212
213 err = misc_register(&ep93xx_wdt_miscdev);
214
215 boot_status = __raw_readl(EP93XX_WDT_WATCHDOG) & 0x01 ? 1 : 0;
216
217 printk(KERN_INFO PFX "EP93XX watchdog, driver version "
218 WDT_VERSION "%s\n",
219 (__raw_readl(EP93XX_WDT_WATCHDOG) & 0x08)
220 ? " (nCS1 disable detected)" : "");
221
222 if (timeout < 1 || timeout > 3600) {
223 timeout = WDT_TIMEOUT;
224 printk(KERN_INFO PFX
225 "timeout value must be 1<=x<=3600, using %d\n",
226 timeout);
227 }
228
229 setup_timer(&timer, ep93xx_timer_ping, 1);
230 return err;
231}
232
233static void __exit ep93xx_wdt_exit(void)
234{
235 wdt_shutdown();
236 misc_deregister(&ep93xx_wdt_miscdev);
237}
238
239module_init(ep93xx_wdt_init);
240module_exit(ep93xx_wdt_exit);
241
242module_param(nowayout, int, 0);
243MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
244
245module_param(timeout, int, 0);
246MODULE_PARM_DESC(timeout,
247 "Watchdog timeout in seconds. (1<=timeout<=3600, default="
248 __MODULE_STRING(WDT_TIMEOUT) ")");
249
250MODULE_AUTHOR("Ray Lehtiniemi <rayl@mail.com>,"
251 "Alessandro Zummo <a.zummo@towertech.it>");
252MODULE_DESCRIPTION("EP93xx Watchdog");
253MODULE_LICENSE("GPL");
254MODULE_VERSION(WDT_VERSION);
255MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);