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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#include <linux/uaccess.h>
32#include <mach/hardware.h>
33
34#define WDT_VERSION "0.3"
35#define PFX "ep93xx_wdt: "
36
37
38#define WDT_TIMEOUT 30
39
40static int nowayout = WATCHDOG_NOWAYOUT;
41static int timeout = WDT_TIMEOUT;
42
43static struct timer_list timer;
44static unsigned long next_heartbeat;
45static unsigned long wdt_status;
46static unsigned long boot_status;
47
48#define WDT_IN_USE 0
49#define WDT_OK_TO_CLOSE 1
50
51#define EP93XX_WDT_REG(x) (EP93XX_WATCHDOG_BASE + (x))
52#define EP93XX_WDT_WATCHDOG EP93XX_WDT_REG(0x00)
53#define EP93XX_WDT_WDSTATUS EP93XX_WDT_REG(0x04)
54
55
56#define WDT_INTERVAL (HZ/5)
57
58static void wdt_enable(void)
59{
60 __raw_writew(0xaaaa, EP93XX_WDT_WATCHDOG);
61}
62
63static void wdt_disable(void)
64{
65 __raw_writew(0xaa55, EP93XX_WDT_WATCHDOG);
66}
67
68static inline void wdt_ping(void)
69{
70 __raw_writew(0x5555, EP93XX_WDT_WATCHDOG);
71}
72
73static void wdt_startup(void)
74{
75 next_heartbeat = jiffies + (timeout * HZ);
76
77 wdt_enable();
78 mod_timer(&timer, jiffies + WDT_INTERVAL);
79}
80
81static void wdt_shutdown(void)
82{
83 del_timer_sync(&timer);
84 wdt_disable();
85}
86
87static void wdt_keepalive(void)
88{
89
90 next_heartbeat = jiffies + (timeout * HZ);
91}
92
93static int ep93xx_wdt_open(struct inode *inode, struct file *file)
94{
95 if (test_and_set_bit(WDT_IN_USE, &wdt_status))
96 return -EBUSY;
97
98 clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
99
100 wdt_startup();
101
102 return nonseekable_open(inode, file);
103}
104
105static ssize_t
106ep93xx_wdt_write(struct file *file, const char __user *data, size_t len,
107 loff_t *ppos)
108{
109 if (len) {
110 if (!nowayout) {
111 size_t i;
112
113 clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
114
115 for (i = 0; i != len; i++) {
116 char c;
117
118 if (get_user(c, data + i))
119 return -EFAULT;
120
121 if (c == 'V')
122 set_bit(WDT_OK_TO_CLOSE, &wdt_status);
123 else
124 clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
125 }
126 }
127 wdt_keepalive();
128 }
129
130 return len;
131}
132
133static struct watchdog_info ident = {
134 .options = WDIOF_CARDRESET | WDIOF_MAGICCLOSE,
135 .identity = "EP93xx Watchdog",
136};
137
138static long ep93xx_wdt_ioctl(struct file *file,
139 unsigned int cmd, unsigned long arg)
140{
141 int ret = -ENOTTY;
142
143 switch (cmd) {
144 case WDIOC_GETSUPPORT:
145 ret = copy_to_user((struct watchdog_info __user *)arg, &ident,
146 sizeof(ident)) ? -EFAULT : 0;
147 break;
148
149 case WDIOC_GETSTATUS:
150 ret = put_user(0, (int __user *)arg);
151 break;
152
153 case WDIOC_GETBOOTSTATUS:
154 ret = put_user(boot_status, (int __user *)arg);
155 break;
156
157 case WDIOC_KEEPALIVE:
158 wdt_keepalive();
159 ret = 0;
160 break;
161
162 case WDIOC_GETTIMEOUT:
163
164 ret = put_user(1, (int __user *)arg);
165 break;
166 }
167 return ret;
168}
169
170static int ep93xx_wdt_release(struct inode *inode, struct file *file)
171{
172 if (test_bit(WDT_OK_TO_CLOSE, &wdt_status))
173 wdt_shutdown();
174 else
175 printk(KERN_CRIT PFX
176 "Device closed unexpectedly - timer will not stop\n");
177
178 clear_bit(WDT_IN_USE, &wdt_status);
179 clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
180
181 return 0;
182}
183
184static const struct file_operations ep93xx_wdt_fops = {
185 .owner = THIS_MODULE,
186 .write = ep93xx_wdt_write,
187 .unlocked_ioctl = ep93xx_wdt_ioctl,
188 .open = ep93xx_wdt_open,
189 .release = ep93xx_wdt_release,
190};
191
192static struct miscdevice ep93xx_wdt_miscdev = {
193 .minor = WATCHDOG_MINOR,
194 .name = "watchdog",
195 .fops = &ep93xx_wdt_fops,
196};
197
198static void ep93xx_timer_ping(unsigned long data)
199{
200 if (time_before(jiffies, next_heartbeat))
201 wdt_ping();
202
203
204 mod_timer(&timer, jiffies + WDT_INTERVAL);
205}
206
207static int __init ep93xx_wdt_init(void)
208{
209 int err;
210
211 err = misc_register(&ep93xx_wdt_miscdev);
212
213 boot_status = __raw_readl(EP93XX_WDT_WATCHDOG) & 0x01 ? 1 : 0;
214
215 printk(KERN_INFO PFX "EP93XX watchdog, driver version "
216 WDT_VERSION "%s\n",
217 (__raw_readl(EP93XX_WDT_WATCHDOG) & 0x08)
218 ? " (nCS1 disable detected)" : "");
219
220 if (timeout < 1 || timeout > 3600) {
221 timeout = WDT_TIMEOUT;
222 printk(KERN_INFO PFX
223 "timeout value must be 1<=x<=3600, using %d\n",
224 timeout);
225 }
226
227 setup_timer(&timer, ep93xx_timer_ping, 1);
228 return err;
229}
230
231static void __exit ep93xx_wdt_exit(void)
232{
233 wdt_shutdown();
234 misc_deregister(&ep93xx_wdt_miscdev);
235}
236
237module_init(ep93xx_wdt_init);
238module_exit(ep93xx_wdt_exit);
239
240module_param(nowayout, int, 0);
241MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
242
243module_param(timeout, int, 0);
244MODULE_PARM_DESC(timeout,
245 "Watchdog timeout in seconds. (1<=timeout<=3600, default="
246 __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
