]> nv-tegra.nvidia Code Review - linux-2.6.git/blob - drivers/watchdog/orion5x_wdt.c
Merge git://git.kernel.org/pub/scm/linux/kernel/git/wim/linux-2.6-watchdog
[linux-2.6.git] / 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/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 <plat/orion5x_wdt.h>
26
27 /*
28  * Watchdog timer block registers.
29  */
30 #define TIMER_CTRL              (TIMER_VIRT_BASE + 0x0000)
31 #define  WDT_EN                 0x0010
32 #define WDT_VAL                 (TIMER_VIRT_BASE + 0x0024)
33
34 #define WDT_MAX_CYCLE_COUNT     0xffffffff
35 #define WDT_IN_USE              0
36 #define WDT_OK_TO_CLOSE         1
37
38 static int nowayout = WATCHDOG_NOWAYOUT;
39 static int heartbeat = -1;              /* module parameter (seconds) */
40 static unsigned int wdt_max_duration;   /* (seconds) */
41 static unsigned int wdt_tclk;
42 static unsigned long wdt_status;
43 static spinlock_t wdt_lock;
44
45 static void orion5x_wdt_ping(void)
46 {
47         spin_lock(&wdt_lock);
48
49         /* Reload watchdog duration */
50         writel(wdt_tclk * heartbeat, WDT_VAL);
51
52         spin_unlock(&wdt_lock);
53 }
54
55 static void orion5x_wdt_enable(void)
56 {
57         u32 reg;
58
59         spin_lock(&wdt_lock);
60
61         /* Set watchdog duration */
62         writel(wdt_tclk * heartbeat, WDT_VAL);
63
64         /* Clear watchdog timer interrupt */
65         reg = readl(BRIDGE_CAUSE);
66         reg &= ~WDT_INT_REQ;
67         writel(reg, BRIDGE_CAUSE);
68
69         /* Enable watchdog timer */
70         reg = readl(TIMER_CTRL);
71         reg |= WDT_EN;
72         writel(reg, TIMER_CTRL);
73
74         /* Enable reset on watchdog */
75         reg = readl(CPU_RESET_MASK);
76         reg |= WDT_RESET;
77         writel(reg, CPU_RESET_MASK);
78
79         spin_unlock(&wdt_lock);
80 }
81
82 static void orion5x_wdt_disable(void)
83 {
84         u32 reg;
85
86         spin_lock(&wdt_lock);
87
88         /* Disable reset on watchdog */
89         reg = readl(CPU_RESET_MASK);
90         reg &= ~WDT_RESET;
91         writel(reg, CPU_RESET_MASK);
92
93         /* Disable watchdog timer */
94         reg = readl(TIMER_CTRL);
95         reg &= ~WDT_EN;
96         writel(reg, TIMER_CTRL);
97
98         spin_unlock(&wdt_lock);
99 }
100
101 static int orion5x_wdt_get_timeleft(int *time_left)
102 {
103         spin_lock(&wdt_lock);
104         *time_left = readl(WDT_VAL) / wdt_tclk;
105         spin_unlock(&wdt_lock);
106         return 0;
107 }
108
109 static int orion5x_wdt_open(struct inode *inode, struct file *file)
110 {
111         if (test_and_set_bit(WDT_IN_USE, &wdt_status))
112                 return -EBUSY;
113         clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
114         orion5x_wdt_enable();
115         return nonseekable_open(inode, file);
116 }
117
118 static ssize_t orion5x_wdt_write(struct file *file, const char *data,
119                                         size_t len, loff_t *ppos)
120 {
121         if (len) {
122                 if (!nowayout) {
123                         size_t i;
124
125                         clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
126                         for (i = 0; i != len; i++) {
127                                 char c;
128
129                                 if (get_user(c, data + i))
130                                         return -EFAULT;
131                                 if (c == 'V')
132                                         set_bit(WDT_OK_TO_CLOSE, &wdt_status);
133                         }
134                 }
135                 orion5x_wdt_ping();
136         }
137         return len;
138 }
139
140 static int orion5x_wdt_settimeout(int new_time)
141 {
142         if ((new_time <= 0) || (new_time > wdt_max_duration))
143                 return -EINVAL;
144
145         /* Set new watchdog time to be used when
146          * orion5x_wdt_enable() or orion5x_wdt_ping() is called. */
147         heartbeat = new_time;
148         return 0;
149 }
150
151 static const struct watchdog_info ident = {
152         .options        = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT |
153                           WDIOF_KEEPALIVEPING,
154         .identity       = "Orion5x Watchdog",
155 };
156
157 static long orion5x_wdt_ioctl(struct file *file, unsigned int cmd,
158                                 unsigned long arg)
159 {
160         int ret = -ENOTTY;
161         int time;
162
163         switch (cmd) {
164         case WDIOC_GETSUPPORT:
165                 ret = copy_to_user((struct watchdog_info *)arg, &ident,
166                                    sizeof(ident)) ? -EFAULT : 0;
167                 break;
168
169         case WDIOC_GETSTATUS:
170         case WDIOC_GETBOOTSTATUS:
171                 ret = put_user(0, (int *)arg);
172                 break;
173
174         case WDIOC_KEEPALIVE:
175                 orion5x_wdt_ping();
176                 ret = 0;
177                 break;
178
179         case WDIOC_SETTIMEOUT:
180                 ret = get_user(time, (int *)arg);
181                 if (ret)
182                         break;
183
184                 if (orion5x_wdt_settimeout(time)) {
185                         ret = -EINVAL;
186                         break;
187                 }
188                 orion5x_wdt_ping();
189                 /* Fall through */
190
191         case WDIOC_GETTIMEOUT:
192                 ret = put_user(heartbeat, (int *)arg);
193                 break;
194
195         case WDIOC_GETTIMELEFT:
196                 if (orion5x_wdt_get_timeleft(&time)) {
197                         ret = -EINVAL;
198                         break;
199                 }
200                 ret = put_user(time, (int *)arg);
201                 break;
202         }
203         return ret;
204 }
205
206 static int orion5x_wdt_release(struct inode *inode, struct file *file)
207 {
208         if (test_bit(WDT_OK_TO_CLOSE, &wdt_status))
209                 orion5x_wdt_disable();
210         else
211                 printk(KERN_CRIT "WATCHDOG: Device closed unexpectedly - "
212                                         "timer will not stop\n");
213         clear_bit(WDT_IN_USE, &wdt_status);
214         clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
215
216         return 0;
217 }
218
219
220 static const struct file_operations orion5x_wdt_fops = {
221         .owner          = THIS_MODULE,
222         .llseek         = no_llseek,
223         .write          = orion5x_wdt_write,
224         .unlocked_ioctl = orion5x_wdt_ioctl,
225         .open           = orion5x_wdt_open,
226         .release        = orion5x_wdt_release,
227 };
228
229 static struct miscdevice orion5x_wdt_miscdev = {
230         .minor          = WATCHDOG_MINOR,
231         .name           = "watchdog",
232         .fops           = &orion5x_wdt_fops,
233 };
234
235 static int __devinit orion5x_wdt_probe(struct platform_device *pdev)
236 {
237         struct orion5x_wdt_platform_data *pdata = pdev->dev.platform_data;
238         int ret;
239
240         if (pdata) {
241                 wdt_tclk = pdata->tclk;
242         } else {
243                 printk(KERN_ERR "Orion5x Watchdog misses platform data\n");
244                 return -ENODEV;
245         }
246
247         if (orion5x_wdt_miscdev.parent)
248                 return -EBUSY;
249         orion5x_wdt_miscdev.parent = &pdev->dev;
250
251         wdt_max_duration = WDT_MAX_CYCLE_COUNT / wdt_tclk;
252         if (orion5x_wdt_settimeout(heartbeat))
253                 heartbeat = wdt_max_duration;
254
255         ret = misc_register(&orion5x_wdt_miscdev);
256         if (ret)
257                 return ret;
258
259         printk(KERN_INFO "Orion5x Watchdog Timer: Initial timeout %d sec%s\n",
260                                 heartbeat, nowayout ? ", nowayout" : "");
261         return 0;
262 }
263
264 static int __devexit orion5x_wdt_remove(struct platform_device *pdev)
265 {
266         int ret;
267
268         if (test_bit(WDT_IN_USE, &wdt_status)) {
269                 orion5x_wdt_disable();
270                 clear_bit(WDT_IN_USE, &wdt_status);
271         }
272
273         ret = misc_deregister(&orion5x_wdt_miscdev);
274         if (!ret)
275                 orion5x_wdt_miscdev.parent = NULL;
276
277         return ret;
278 }
279
280 static void orion5x_wdt_shutdown(struct platform_device *pdev)
281 {
282         if (test_bit(WDT_IN_USE, &wdt_status))
283                 orion5x_wdt_disable();
284 }
285
286 static struct platform_driver orion5x_wdt_driver = {
287         .probe          = orion5x_wdt_probe,
288         .remove         = __devexit_p(orion5x_wdt_remove),
289         .shutdown       = orion5x_wdt_shutdown,
290         .driver         = {
291                 .owner  = THIS_MODULE,
292                 .name   = "orion5x_wdt",
293         },
294 };
295
296 static int __init orion5x_wdt_init(void)
297 {
298         spin_lock_init(&wdt_lock);
299         return platform_driver_register(&orion5x_wdt_driver);
300 }
301
302 static void __exit orion5x_wdt_exit(void)
303 {
304         platform_driver_unregister(&orion5x_wdt_driver);
305 }
306
307 module_init(orion5x_wdt_init);
308 module_exit(orion5x_wdt_exit);
309
310 MODULE_AUTHOR("Sylver Bruneau <sylver.bruneau@googlemail.com>");
311 MODULE_DESCRIPTION("Orion5x Processor Watchdog");
312
313 module_param(heartbeat, int, 0);
314 MODULE_PARM_DESC(heartbeat, "Initial watchdog heartbeat in seconds");
315
316 module_param(nowayout, int, 0);
317 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
318                                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
319
320 MODULE_LICENSE("GPL");
321 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);