media: soc_camera: tegra: fix one building warning
[linux-2.6.git] / drivers / watchdog / orion_wdt.c
1 /*
2  * drivers/watchdog/orion_wdt.c
3  *
4  * Watchdog driver for Orion/Kirkwood 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/platform_device.h>
20 #include <linux/watchdog.h>
21 #include <linux/init.h>
22 #include <linux/uaccess.h>
23 #include <linux/io.h>
24 #include <linux/spinlock.h>
25 #include <mach/bridge-regs.h>
26 #include <plat/orion_wdt.h>
27
28 /*
29  * Watchdog timer block registers.
30  */
31 #define TIMER_CTRL              (TIMER_VIRT_BASE + 0x0000)
32 #define  WDT_EN                 0x0010
33 #define WDT_VAL                 (TIMER_VIRT_BASE + 0x0024)
34
35 #define WDT_MAX_CYCLE_COUNT     0xffffffff
36 #define WDT_IN_USE              0
37 #define WDT_OK_TO_CLOSE         1
38
39 static int nowayout = WATCHDOG_NOWAYOUT;
40 static int heartbeat = -1;              /* module parameter (seconds) */
41 static unsigned int wdt_max_duration;   /* (seconds) */
42 static unsigned int wdt_tclk;
43 static unsigned long wdt_status;
44 static spinlock_t wdt_lock;
45
46 static void orion_wdt_ping(void)
47 {
48         spin_lock(&wdt_lock);
49
50         /* Reload watchdog duration */
51         writel(wdt_tclk * heartbeat, WDT_VAL);
52
53         spin_unlock(&wdt_lock);
54 }
55
56 static void orion_wdt_enable(void)
57 {
58         u32 reg;
59
60         spin_lock(&wdt_lock);
61
62         /* Set watchdog duration */
63         writel(wdt_tclk * heartbeat, WDT_VAL);
64
65         /* Clear watchdog timer interrupt */
66         reg = readl(BRIDGE_CAUSE);
67         reg &= ~WDT_INT_REQ;
68         writel(reg, BRIDGE_CAUSE);
69
70         /* Enable watchdog timer */
71         reg = readl(TIMER_CTRL);
72         reg |= WDT_EN;
73         writel(reg, TIMER_CTRL);
74
75         /* Enable reset on watchdog */
76         reg = readl(RSTOUTn_MASK);
77         reg |= WDT_RESET_OUT_EN;
78         writel(reg, RSTOUTn_MASK);
79
80         spin_unlock(&wdt_lock);
81 }
82
83 static void orion_wdt_disable(void)
84 {
85         u32 reg;
86
87         spin_lock(&wdt_lock);
88
89         /* Disable reset on watchdog */
90         reg = readl(RSTOUTn_MASK);
91         reg &= ~WDT_RESET_OUT_EN;
92         writel(reg, RSTOUTn_MASK);
93
94         /* Disable watchdog timer */
95         reg = readl(TIMER_CTRL);
96         reg &= ~WDT_EN;
97         writel(reg, TIMER_CTRL);
98
99         spin_unlock(&wdt_lock);
100 }
101
102 static int orion_wdt_get_timeleft(int *time_left)
103 {
104         spin_lock(&wdt_lock);
105         *time_left = readl(WDT_VAL) / wdt_tclk;
106         spin_unlock(&wdt_lock);
107         return 0;
108 }
109
110 static int orion_wdt_open(struct inode *inode, struct file *file)
111 {
112         if (test_and_set_bit(WDT_IN_USE, &wdt_status))
113                 return -EBUSY;
114         clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
115         orion_wdt_enable();
116         return nonseekable_open(inode, file);
117 }
118
119 static ssize_t orion_wdt_write(struct file *file, const char *data,
120                                         size_t len, loff_t *ppos)
121 {
122         if (len) {
123                 if (!nowayout) {
124                         size_t i;
125
126                         clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
127                         for (i = 0; i != len; i++) {
128                                 char c;
129
130                                 if (get_user(c, data + i))
131                                         return -EFAULT;
132                                 if (c == 'V')
133                                         set_bit(WDT_OK_TO_CLOSE, &wdt_status);
134                         }
135                 }
136                 orion_wdt_ping();
137         }
138         return len;
139 }
140
141 static int orion_wdt_settimeout(int new_time)
142 {
143         if ((new_time <= 0) || (new_time > wdt_max_duration))
144                 return -EINVAL;
145
146         /* Set new watchdog time to be used when
147          * orion_wdt_enable() or orion_wdt_ping() is called. */
148         heartbeat = new_time;
149         return 0;
150 }
151
152 static const struct watchdog_info ident = {
153         .options        = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT |
154                           WDIOF_KEEPALIVEPING,
155         .identity       = "Orion Watchdog",
156 };
157
158 static long orion_wdt_ioctl(struct file *file, unsigned int cmd,
159                                 unsigned long arg)
160 {
161         int ret = -ENOTTY;
162         int time;
163
164         switch (cmd) {
165         case WDIOC_GETSUPPORT:
166                 ret = copy_to_user((struct watchdog_info *)arg, &ident,
167                                    sizeof(ident)) ? -EFAULT : 0;
168                 break;
169
170         case WDIOC_GETSTATUS:
171         case WDIOC_GETBOOTSTATUS:
172                 ret = put_user(0, (int *)arg);
173                 break;
174
175         case WDIOC_KEEPALIVE:
176                 orion_wdt_ping();
177                 ret = 0;
178                 break;
179
180         case WDIOC_SETTIMEOUT:
181                 ret = get_user(time, (int *)arg);
182                 if (ret)
183                         break;
184
185                 if (orion_wdt_settimeout(time)) {
186                         ret = -EINVAL;
187                         break;
188                 }
189                 orion_wdt_ping();
190                 /* Fall through */
191
192         case WDIOC_GETTIMEOUT:
193                 ret = put_user(heartbeat, (int *)arg);
194                 break;
195
196         case WDIOC_GETTIMELEFT:
197                 if (orion_wdt_get_timeleft(&time)) {
198                         ret = -EINVAL;
199                         break;
200                 }
201                 ret = put_user(time, (int *)arg);
202                 break;
203         }
204         return ret;
205 }
206
207 static int orion_wdt_release(struct inode *inode, struct file *file)
208 {
209         if (test_bit(WDT_OK_TO_CLOSE, &wdt_status))
210                 orion_wdt_disable();
211         else
212                 printk(KERN_CRIT "WATCHDOG: Device closed unexpectedly - "
213                                         "timer will not stop\n");
214         clear_bit(WDT_IN_USE, &wdt_status);
215         clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
216
217         return 0;
218 }
219
220
221 static const struct file_operations orion_wdt_fops = {
222         .owner          = THIS_MODULE,
223         .llseek         = no_llseek,
224         .write          = orion_wdt_write,
225         .unlocked_ioctl = orion_wdt_ioctl,
226         .open           = orion_wdt_open,
227         .release        = orion_wdt_release,
228 };
229
230 static struct miscdevice orion_wdt_miscdev = {
231         .minor          = WATCHDOG_MINOR,
232         .name           = "watchdog",
233         .fops           = &orion_wdt_fops,
234 };
235
236 static int __devinit orion_wdt_probe(struct platform_device *pdev)
237 {
238         struct orion_wdt_platform_data *pdata = pdev->dev.platform_data;
239         int ret;
240
241         if (pdata) {
242                 wdt_tclk = pdata->tclk;
243         } else {
244                 printk(KERN_ERR "Orion Watchdog misses platform data\n");
245                 return -ENODEV;
246         }
247
248         if (orion_wdt_miscdev.parent)
249                 return -EBUSY;
250         orion_wdt_miscdev.parent = &pdev->dev;
251
252         wdt_max_duration = WDT_MAX_CYCLE_COUNT / wdt_tclk;
253         if (orion_wdt_settimeout(heartbeat))
254                 heartbeat = wdt_max_duration;
255
256         ret = misc_register(&orion_wdt_miscdev);
257         if (ret)
258                 return ret;
259
260         printk(KERN_INFO "Orion Watchdog Timer: Initial timeout %d sec%s\n",
261                                 heartbeat, nowayout ? ", nowayout" : "");
262         return 0;
263 }
264
265 static int __devexit orion_wdt_remove(struct platform_device *pdev)
266 {
267         int ret;
268
269         if (test_bit(WDT_IN_USE, &wdt_status)) {
270                 orion_wdt_disable();
271                 clear_bit(WDT_IN_USE, &wdt_status);
272         }
273
274         ret = misc_deregister(&orion_wdt_miscdev);
275         if (!ret)
276                 orion_wdt_miscdev.parent = NULL;
277
278         return ret;
279 }
280
281 static void orion_wdt_shutdown(struct platform_device *pdev)
282 {
283         if (test_bit(WDT_IN_USE, &wdt_status))
284                 orion_wdt_disable();
285 }
286
287 static struct platform_driver orion_wdt_driver = {
288         .probe          = orion_wdt_probe,
289         .remove         = __devexit_p(orion_wdt_remove),
290         .shutdown       = orion_wdt_shutdown,
291         .driver         = {
292                 .owner  = THIS_MODULE,
293                 .name   = "orion_wdt",
294         },
295 };
296
297 static int __init orion_wdt_init(void)
298 {
299         spin_lock_init(&wdt_lock);
300         return platform_driver_register(&orion_wdt_driver);
301 }
302
303 static void __exit orion_wdt_exit(void)
304 {
305         platform_driver_unregister(&orion_wdt_driver);
306 }
307
308 module_init(orion_wdt_init);
309 module_exit(orion_wdt_exit);
310
311 MODULE_AUTHOR("Sylver Bruneau <sylver.bruneau@googlemail.com>");
312 MODULE_DESCRIPTION("Orion Processor Watchdog");
313
314 module_param(heartbeat, int, 0);
315 MODULE_PARM_DESC(heartbeat, "Initial watchdog heartbeat in seconds");
316
317 module_param(nowayout, int, 0);
318 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
319                                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
320
321 MODULE_LICENSE("GPL");
322 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);