Merge branch 'topic/emu10k1' into for-linus
[linux-2.6] / drivers / watchdog / orion5x_wdt.c
1 /*
2  * drivers/watchdog/orion5x_wdt.c
3  *
4  * Watchdog driver for Orion5x processors
5  *
6  * Author: Sylver Bruneau <sylver.bruneau@googlemail.com>
7  *
8  * This file is licensed under  the terms of the GNU General Public
9  * License version 2. This program is licensed "as is" without any
10  * warranty of any kind, whether express or implied.
11  */
12
13 #include <linux/module.h>
14 #include <linux/moduleparam.h>
15 #include <linux/types.h>
16 #include <linux/kernel.h>
17 #include <linux/fs.h>
18 #include <linux/miscdevice.h>
19 #include <linux/watchdog.h>
20 #include <linux/init.h>
21 #include <linux/uaccess.h>
22 #include <linux/io.h>
23 #include <linux/spinlock.h>
24
25 /*
26  * Watchdog timer block registers.
27  */
28 #define TIMER_CTRL              (TIMER_VIRT_BASE + 0x0000)
29 #define  WDT_EN                 0x0010
30 #define WDT_VAL                 (TIMER_VIRT_BASE + 0x0024)
31
32 #define ORION5X_TCLK            166666667
33 #define WDT_MAX_DURATION        (0xffffffff / ORION5X_TCLK)
34 #define WDT_IN_USE              0
35 #define WDT_OK_TO_CLOSE         1
36
37 static int nowayout = WATCHDOG_NOWAYOUT;
38 static int heartbeat =  WDT_MAX_DURATION;       /* (seconds) */
39 static unsigned long wdt_status;
40 static spinlock_t wdt_lock;
41
42 static void wdt_enable(void)
43 {
44         u32 reg;
45
46         spin_lock(&wdt_lock);
47
48         /* Set watchdog duration */
49         writel(ORION5X_TCLK * heartbeat, WDT_VAL);
50
51         /* Clear watchdog timer interrupt */
52         reg = readl(BRIDGE_CAUSE);
53         reg &= ~WDT_INT_REQ;
54         writel(reg, BRIDGE_CAUSE);
55
56         /* Enable watchdog timer */
57         reg = readl(TIMER_CTRL);
58         reg |= WDT_EN;
59         writel(reg, TIMER_CTRL);
60
61         /* Enable reset on watchdog */
62         reg = readl(CPU_RESET_MASK);
63         reg |= WDT_RESET;
64         writel(reg, CPU_RESET_MASK);
65
66         spin_unlock(&wdt_lock);
67 }
68
69 static void wdt_disable(void)
70 {
71         u32 reg;
72
73         spin_lock(&wdt_lock);
74
75         /* Disable reset on watchdog */
76         reg = readl(CPU_RESET_MASK);
77         reg &= ~WDT_RESET;
78         writel(reg, CPU_RESET_MASK);
79
80         /* Disable watchdog timer */
81         reg = readl(TIMER_CTRL);
82         reg &= ~WDT_EN;
83         writel(reg, TIMER_CTRL);
84
85         spin_unlock(&wdt_lock);
86 }
87
88 static int orion5x_wdt_get_timeleft(int *time_left)
89 {
90         spin_lock(&wdt_lock);
91         *time_left = readl(WDT_VAL) / ORION5X_TCLK;
92         spin_unlock(&wdt_lock);
93         return 0;
94 }
95
96 static int orion5x_wdt_open(struct inode *inode, struct file *file)
97 {
98         if (test_and_set_bit(WDT_IN_USE, &wdt_status))
99                 return -EBUSY;
100         clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
101         wdt_enable();
102         return nonseekable_open(inode, file);
103 }
104
105 static ssize_t orion5x_wdt_write(struct file *file, const char *data,
106                                         size_t len, loff_t *ppos)
107 {
108         if (len) {
109                 if (!nowayout) {
110                         size_t i;
111
112                         clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
113                         for (i = 0; i != len; i++) {
114                                 char c;
115
116                                 if (get_user(c, data + i))
117                                         return -EFAULT;
118                                 if (c == 'V')
119                                         set_bit(WDT_OK_TO_CLOSE, &wdt_status);
120                         }
121                 }
122                 wdt_enable();
123         }
124         return len;
125 }
126
127 static struct watchdog_info ident = {
128         .options        = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT |
129                           WDIOF_KEEPALIVEPING,
130         .identity       = "Orion5x Watchdog",
131 };
132
133
134 static long orion5x_wdt_ioctl(struct file *file, unsigned int cmd,
135                                 unsigned long arg)
136 {
137         int ret = -ENOTTY;
138         int time;
139
140         switch (cmd) {
141         case WDIOC_GETSUPPORT:
142                 ret = copy_to_user((struct watchdog_info *)arg, &ident,
143                                    sizeof(ident)) ? -EFAULT : 0;
144                 break;
145
146         case WDIOC_GETSTATUS:
147         case WDIOC_GETBOOTSTATUS:
148                 ret = put_user(0, (int *)arg);
149                 break;
150
151         case WDIOC_KEEPALIVE:
152                 wdt_enable();
153                 ret = 0;
154                 break;
155
156         case WDIOC_SETTIMEOUT:
157                 ret = get_user(time, (int *)arg);
158                 if (ret)
159                         break;
160
161                 if (time <= 0 || time > WDT_MAX_DURATION) {
162                         ret = -EINVAL;
163                         break;
164                 }
165                 heartbeat = time;
166                 wdt_enable();
167                 /* Fall through */
168
169         case WDIOC_GETTIMEOUT:
170                 ret = put_user(heartbeat, (int *)arg);
171                 break;
172
173         case WDIOC_GETTIMELEFT:
174                 if (orion5x_wdt_get_timeleft(&time)) {
175                         ret = -EINVAL;
176                         break;
177                 }
178                 ret = put_user(time, (int *)arg);
179                 break;
180         }
181         return ret;
182 }
183
184 static int orion5x_wdt_release(struct inode *inode, struct file *file)
185 {
186         if (test_bit(WDT_OK_TO_CLOSE, &wdt_status))
187                 wdt_disable();
188         else
189                 printk(KERN_CRIT "WATCHDOG: Device closed unexpectedly - "
190                                         "timer will not stop\n");
191         clear_bit(WDT_IN_USE, &wdt_status);
192         clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
193
194         return 0;
195 }
196
197
198 static const struct file_operations orion5x_wdt_fops = {
199         .owner          = THIS_MODULE,
200         .llseek         = no_llseek,
201         .write          = orion5x_wdt_write,
202         .unlocked_ioctl = orion5x_wdt_ioctl,
203         .open           = orion5x_wdt_open,
204         .release        = orion5x_wdt_release,
205 };
206
207 static struct miscdevice orion5x_wdt_miscdev = {
208         .minor          = WATCHDOG_MINOR,
209         .name           = "watchdog",
210         .fops           = &orion5x_wdt_fops,
211 };
212
213 static int __init orion5x_wdt_init(void)
214 {
215         int ret;
216
217         spin_lock_init(&wdt_lock);
218
219         ret = misc_register(&orion5x_wdt_miscdev);
220         if (ret == 0)
221                 printk("Orion5x Watchdog Timer: heartbeat %d sec\n",
222                                                                 heartbeat);
223
224         return ret;
225 }
226
227 static void __exit orion5x_wdt_exit(void)
228 {
229         misc_deregister(&orion5x_wdt_miscdev);
230 }
231
232 module_init(orion5x_wdt_init);
233 module_exit(orion5x_wdt_exit);
234
235 MODULE_AUTHOR("Sylver Bruneau <sylver.bruneau@googlemail.com>");
236 MODULE_DESCRIPTION("Orion5x Processor Watchdog");
237
238 module_param(heartbeat, int, 0);
239 MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds (default is "
240                                         __MODULE_STRING(WDT_MAX_DURATION) ")");
241
242 module_param(nowayout, int, 0);
243 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
244
245 MODULE_LICENSE("GPL");
246 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);