watchdog: nowayout is bool
[linux-3.10.git] / drivers / watchdog / bcm63xx_wdt.c
1 /*
2  *  Broadcom BCM63xx SoC watchdog driver
3  *
4  *  Copyright (C) 2007, Miguel Gaio <miguel.gaio@efixo.com>
5  *  Copyright (C) 2008, Florian Fainelli <florian@openwrt.org>
6  *
7  *  This program is free software; you can redistribute it and/or
8  *  modify it under the terms of the GNU General Public License
9  *  as published by the Free Software Foundation; either version
10  *  2 of the License, or (at your option) any later version.
11  */
12
13 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
14
15 #include <linux/bitops.h>
16 #include <linux/errno.h>
17 #include <linux/fs.h>
18 #include <linux/init.h>
19 #include <linux/kernel.h>
20 #include <linux/miscdevice.h>
21 #include <linux/module.h>
22 #include <linux/moduleparam.h>
23 #include <linux/types.h>
24 #include <linux/uaccess.h>
25 #include <linux/watchdog.h>
26 #include <linux/timer.h>
27 #include <linux/jiffies.h>
28 #include <linux/interrupt.h>
29 #include <linux/ptrace.h>
30 #include <linux/resource.h>
31 #include <linux/platform_device.h>
32
33 #include <bcm63xx_cpu.h>
34 #include <bcm63xx_io.h>
35 #include <bcm63xx_regs.h>
36 #include <bcm63xx_timer.h>
37
38 #define PFX KBUILD_MODNAME
39
40 #define WDT_HZ          50000000 /* Fclk */
41 #define WDT_DEFAULT_TIME        30      /* seconds */
42 #define WDT_MAX_TIME            256     /* seconds */
43
44 static struct {
45         void __iomem *regs;
46         struct timer_list timer;
47         int default_ticks;
48         unsigned long inuse;
49         atomic_t ticks;
50 } bcm63xx_wdt_device;
51
52 static int expect_close;
53
54 static int wdt_time = WDT_DEFAULT_TIME;
55 static bool nowayout = WATCHDOG_NOWAYOUT;
56 module_param(nowayout, bool, 0);
57 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
58         __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
59
60 /* HW functions */
61 static void bcm63xx_wdt_hw_start(void)
62 {
63         bcm_writel(0xfffffffe, bcm63xx_wdt_device.regs + WDT_DEFVAL_REG);
64         bcm_writel(WDT_START_1, bcm63xx_wdt_device.regs + WDT_CTL_REG);
65         bcm_writel(WDT_START_2, bcm63xx_wdt_device.regs + WDT_CTL_REG);
66 }
67
68 static void bcm63xx_wdt_hw_stop(void)
69 {
70         bcm_writel(WDT_STOP_1, bcm63xx_wdt_device.regs + WDT_CTL_REG);
71         bcm_writel(WDT_STOP_2, bcm63xx_wdt_device.regs + WDT_CTL_REG);
72 }
73
74 static void bcm63xx_wdt_isr(void *data)
75 {
76         struct pt_regs *regs = get_irq_regs();
77
78         die(PFX " fire", regs);
79 }
80
81 static void bcm63xx_timer_tick(unsigned long unused)
82 {
83         if (!atomic_dec_and_test(&bcm63xx_wdt_device.ticks)) {
84                 bcm63xx_wdt_hw_start();
85                 mod_timer(&bcm63xx_wdt_device.timer, jiffies + HZ);
86         } else
87                 pr_crit("watchdog will restart system\n");
88 }
89
90 static void bcm63xx_wdt_pet(void)
91 {
92         atomic_set(&bcm63xx_wdt_device.ticks, wdt_time);
93 }
94
95 static void bcm63xx_wdt_start(void)
96 {
97         bcm63xx_wdt_pet();
98         bcm63xx_timer_tick(0);
99 }
100
101 static void bcm63xx_wdt_pause(void)
102 {
103         del_timer_sync(&bcm63xx_wdt_device.timer);
104         bcm63xx_wdt_hw_stop();
105 }
106
107 static int bcm63xx_wdt_settimeout(int new_time)
108 {
109         if ((new_time <= 0) || (new_time > WDT_MAX_TIME))
110                 return -EINVAL;
111
112         wdt_time = new_time;
113
114         return 0;
115 }
116
117 static int bcm63xx_wdt_open(struct inode *inode, struct file *file)
118 {
119         if (test_and_set_bit(0, &bcm63xx_wdt_device.inuse))
120                 return -EBUSY;
121
122         bcm63xx_wdt_start();
123         return nonseekable_open(inode, file);
124 }
125
126 static int bcm63xx_wdt_release(struct inode *inode, struct file *file)
127 {
128         if (expect_close == 42)
129                 bcm63xx_wdt_pause();
130         else {
131                 pr_crit("Unexpected close, not stopping watchdog!\n");
132                 bcm63xx_wdt_start();
133         }
134         clear_bit(0, &bcm63xx_wdt_device.inuse);
135         expect_close = 0;
136         return 0;
137 }
138
139 static ssize_t bcm63xx_wdt_write(struct file *file, const char *data,
140                                 size_t len, loff_t *ppos)
141 {
142         if (len) {
143                 if (!nowayout) {
144                         size_t i;
145
146                         /* In case it was set long ago */
147                         expect_close = 0;
148
149                         for (i = 0; i != len; i++) {
150                                 char c;
151                                 if (get_user(c, data + i))
152                                         return -EFAULT;
153                                 if (c == 'V')
154                                         expect_close = 42;
155                         }
156                 }
157                 bcm63xx_wdt_pet();
158         }
159         return len;
160 }
161
162 static struct watchdog_info bcm63xx_wdt_info = {
163         .identity       = PFX,
164         .options        = WDIOF_SETTIMEOUT |
165                                 WDIOF_KEEPALIVEPING |
166                                 WDIOF_MAGICCLOSE,
167 };
168
169
170 static long bcm63xx_wdt_ioctl(struct file *file, unsigned int cmd,
171                                 unsigned long arg)
172 {
173         void __user *argp = (void __user *)arg;
174         int __user *p = argp;
175         int new_value, retval = -EINVAL;
176
177         switch (cmd) {
178         case WDIOC_GETSUPPORT:
179                 return copy_to_user(argp, &bcm63xx_wdt_info,
180                         sizeof(bcm63xx_wdt_info)) ? -EFAULT : 0;
181
182         case WDIOC_GETSTATUS:
183         case WDIOC_GETBOOTSTATUS:
184                 return put_user(0, p);
185
186         case WDIOC_SETOPTIONS:
187                 if (get_user(new_value, p))
188                         return -EFAULT;
189
190                 if (new_value & WDIOS_DISABLECARD) {
191                         bcm63xx_wdt_pause();
192                         retval = 0;
193                 }
194                 if (new_value & WDIOS_ENABLECARD) {
195                         bcm63xx_wdt_start();
196                         retval = 0;
197                 }
198
199                 return retval;
200
201         case WDIOC_KEEPALIVE:
202                 bcm63xx_wdt_pet();
203                 return 0;
204
205         case WDIOC_SETTIMEOUT:
206                 if (get_user(new_value, p))
207                         return -EFAULT;
208
209                 if (bcm63xx_wdt_settimeout(new_value))
210                         return -EINVAL;
211
212                 bcm63xx_wdt_pet();
213
214         case WDIOC_GETTIMEOUT:
215                 return put_user(wdt_time, p);
216
217         default:
218                 return -ENOTTY;
219
220         }
221 }
222
223 static const struct file_operations bcm63xx_wdt_fops = {
224         .owner          = THIS_MODULE,
225         .llseek         = no_llseek,
226         .write          = bcm63xx_wdt_write,
227         .unlocked_ioctl = bcm63xx_wdt_ioctl,
228         .open           = bcm63xx_wdt_open,
229         .release        = bcm63xx_wdt_release,
230 };
231
232 static struct miscdevice bcm63xx_wdt_miscdev = {
233         .minor  = WATCHDOG_MINOR,
234         .name   = "watchdog",
235         .fops   = &bcm63xx_wdt_fops,
236 };
237
238
239 static int __devinit bcm63xx_wdt_probe(struct platform_device *pdev)
240 {
241         int ret;
242         struct resource *r;
243
244         setup_timer(&bcm63xx_wdt_device.timer, bcm63xx_timer_tick, 0L);
245
246         r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
247         if (!r) {
248                 dev_err(&pdev->dev, "failed to get resources\n");
249                 return -ENODEV;
250         }
251
252         bcm63xx_wdt_device.regs = ioremap_nocache(r->start, resource_size(r));
253         if (!bcm63xx_wdt_device.regs) {
254                 dev_err(&pdev->dev, "failed to remap I/O resources\n");
255                 return -ENXIO;
256         }
257
258         ret = bcm63xx_timer_register(TIMER_WDT_ID, bcm63xx_wdt_isr, NULL);
259         if (ret < 0) {
260                 dev_err(&pdev->dev, "failed to register wdt timer isr\n");
261                 goto unmap;
262         }
263
264         if (bcm63xx_wdt_settimeout(wdt_time)) {
265                 bcm63xx_wdt_settimeout(WDT_DEFAULT_TIME);
266                 dev_info(&pdev->dev,
267                         ": wdt_time value must be 1 <= wdt_time <= 256, using %d\n",
268                         wdt_time);
269         }
270
271         ret = misc_register(&bcm63xx_wdt_miscdev);
272         if (ret < 0) {
273                 dev_err(&pdev->dev, "failed to register watchdog device\n");
274                 goto unregister_timer;
275         }
276
277         dev_info(&pdev->dev, " started, timer margin: %d sec\n",
278                                                 WDT_DEFAULT_TIME);
279
280         return 0;
281
282 unregister_timer:
283         bcm63xx_timer_unregister(TIMER_WDT_ID);
284 unmap:
285         iounmap(bcm63xx_wdt_device.regs);
286         return ret;
287 }
288
289 static int __devexit bcm63xx_wdt_remove(struct platform_device *pdev)
290 {
291         if (!nowayout)
292                 bcm63xx_wdt_pause();
293
294         misc_deregister(&bcm63xx_wdt_miscdev);
295         bcm63xx_timer_unregister(TIMER_WDT_ID);
296         iounmap(bcm63xx_wdt_device.regs);
297         return 0;
298 }
299
300 static void bcm63xx_wdt_shutdown(struct platform_device *pdev)
301 {
302         bcm63xx_wdt_pause();
303 }
304
305 static struct platform_driver bcm63xx_wdt = {
306         .probe  = bcm63xx_wdt_probe,
307         .remove = __devexit_p(bcm63xx_wdt_remove),
308         .shutdown = bcm63xx_wdt_shutdown,
309         .driver = {
310                 .owner = THIS_MODULE,
311                 .name = "bcm63xx-wdt",
312         }
313 };
314
315 module_platform_driver(bcm63xx_wdt);
316
317 MODULE_AUTHOR("Miguel Gaio <miguel.gaio@efixo.com>");
318 MODULE_AUTHOR("Florian Fainelli <florian@openwrt.org>");
319 MODULE_DESCRIPTION("Driver for the Broadcom BCM63xx SoC watchdog");
320 MODULE_LICENSE("GPL");
321 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
322 MODULE_ALIAS("platform:bcm63xx-wdt");