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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
32#include <asm/hardware.h>
33#include <asm/uaccess.h>
34
35#define WDT_VERSION "0.3"
36#define PFX "ep93xx_wdt: "
37
38
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
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
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 struct watchdog_info ident = {
135 .options = WDIOF_CARDRESET | WDIOF_MAGICCLOSE,
136 .identity = "EP93xx Watchdog",
137};
138
139static int
140ep93xx_wdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
141 unsigned long arg)
142{
143 int ret = -ENOTTY;
144
145 switch (cmd) {
146 case WDIOC_GETSUPPORT:
147 ret = copy_to_user((struct watchdog_info __user *)arg, &ident,
148 sizeof(ident)) ? -EFAULT : 0;
149 break;
150
151 case WDIOC_GETSTATUS:
152 ret = put_user(0, (int __user *)arg);
153 break;
154
155 case WDIOC_GETBOOTSTATUS:
156 ret = put_user(boot_status, (int __user *)arg);
157 break;
158
159 case WDIOC_GETTIMEOUT:
160
161 ret = put_user(1, (int __user *)arg);
162 break;
163
164 case WDIOC_KEEPALIVE:
165 wdt_keepalive();
166 ret = 0;
167 break;
168 }
169 return ret;
170}
171
172static int ep93xx_wdt_release(struct inode *inode, struct file *file)
173{
174 if (test_bit(WDT_OK_TO_CLOSE, &wdt_status))
175 wdt_shutdown();
176 else
177 printk(KERN_CRIT PFX "Device closed unexpectedly - "
178 "timer will not stop\n");
179
180 clear_bit(WDT_IN_USE, &wdt_status);
181 clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
182
183 return 0;
184}
185
186static const struct file_operations ep93xx_wdt_fops = {
187 .owner = THIS_MODULE,
188 .write = ep93xx_wdt_write,
189 .ioctl = ep93xx_wdt_ioctl,
190 .open = ep93xx_wdt_open,
191 .release = ep93xx_wdt_release,
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
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, "Watchdog timeout in seconds. (1<=timeout<=3600, default=" __MODULE_STRING(WATCHDOG_TIMEOUT) ")");
247
248MODULE_AUTHOR("Ray Lehtiniemi <rayl@mail.com>,"
249 "Alessandro Zummo <a.zummo@towertech.it>");
250MODULE_DESCRIPTION("EP93xx Watchdog");
251MODULE_LICENSE("GPL");
252MODULE_VERSION(WDT_VERSION);
253MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
254
