Merge commit 'v2.6.27-rc6' into x86/cleanups
[linux-2.6] / drivers / watchdog / rc32434_wdt.c
1 /*
2  *  IDT Interprise 79RC32434 watchdog driver
3  *
4  *  Copyright (C) 2006, Ondrej Zajicek <santiago@crfreenet.org>
5  *  Copyright (C) 2008, Florian Fainelli <florian@openwrt.org>
6  *
7  *  based on
8  *  SoftDog 0.05:       A Software Watchdog Device
9  *
10  *  (c) Copyright 1996 Alan Cox <alan@redhat.com>, All Rights Reserved.
11  *
12  *  This program is free software; you can redistribute it and/or
13  *  modify it under the terms of the GNU General Public License
14  *  as published by the Free Software Foundation; either version
15  *  2 of the License, or (at your option) any later version.
16  *
17  */
18
19 #include <linux/module.h>
20 #include <linux/types.h>
21 #include <linux/kernel.h>
22 #include <linux/fs.h>
23 #include <linux/mm.h>
24 #include <linux/miscdevice.h>
25 #include <linux/watchdog.h>
26 #include <linux/reboot.h>
27 #include <linux/smp_lock.h>
28 #include <linux/init.h>
29 #include <linux/platform_device.h>
30 #include <linux/uaccess.h>
31
32 #include <asm/bootinfo.h>
33 #include <asm/time.h>
34 #include <asm/mach-rc32434/integ.h>
35
36 #define MAX_TIMEOUT                     20
37 #define RC32434_WDT_INTERVAL            (15 * HZ)
38
39 #define VERSION "0.2"
40
41 static struct {
42         struct completion stop;
43         int running;
44         struct timer_list timer;
45         int queue;
46         int default_ticks;
47         unsigned long inuse;
48 } rc32434_wdt_device;
49
50 static struct integ __iomem *wdt_reg;
51 static int ticks = 100 * HZ;
52
53 static int expect_close;
54 static int timeout;
55
56 static int nowayout = WATCHDOG_NOWAYOUT;
57 module_param(nowayout, int, 0);
58 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
59         __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
60
61
62 static void rc32434_wdt_start(void)
63 {
64         u32 val;
65
66         if (!rc32434_wdt_device.inuse) {
67                 writel(0, &wdt_reg->wtcount);
68
69                 val = RC32434_ERR_WRE;
70                 writel(readl(&wdt_reg->errcs) | val, &wdt_reg->errcs);
71
72                 val = RC32434_WTC_EN;
73                 writel(readl(&wdt_reg->wtc) | val, &wdt_reg->wtc);
74         }
75         rc32434_wdt_device.running++;
76 }
77
78 static void rc32434_wdt_stop(void)
79 {
80         u32 val;
81
82         if (rc32434_wdt_device.running) {
83
84                 val = ~RC32434_WTC_EN;
85                 writel(readl(&wdt_reg->wtc) & val, &wdt_reg->wtc);
86
87                 val = ~RC32434_ERR_WRE;
88                 writel(readl(&wdt_reg->errcs) & val, &wdt_reg->errcs);
89
90                 rc32434_wdt_device.running = 0;
91         }
92 }
93
94 static void rc32434_wdt_set(int new_timeout)
95 {
96         u32 cmp = new_timeout * HZ;
97         u32 state, val;
98
99         timeout = new_timeout;
100         /*
101          * store and disable WTC
102          */
103         state = (u32)(readl(&wdt_reg->wtc) & RC32434_WTC_EN);
104         val = ~RC32434_WTC_EN;
105         writel(readl(&wdt_reg->wtc) & val, &wdt_reg->wtc);
106
107         writel(0, &wdt_reg->wtcount);
108         writel(cmp, &wdt_reg->wtcompare);
109
110         /*
111          * restore WTC
112          */
113
114         writel(readl(&wdt_reg->wtc) | state, &wdt_reg);
115 }
116
117 static void rc32434_wdt_reset(void)
118 {
119         ticks = rc32434_wdt_device.default_ticks;
120 }
121
122 static void rc32434_wdt_update(unsigned long unused)
123 {
124         if (rc32434_wdt_device.running)
125                 ticks--;
126
127         writel(0, &wdt_reg->wtcount);
128
129         if (rc32434_wdt_device.queue && ticks)
130                 mod_timer(&rc32434_wdt_device.timer,
131                         jiffies + RC32434_WDT_INTERVAL);
132         else
133                 complete(&rc32434_wdt_device.stop);
134 }
135
136 static int rc32434_wdt_open(struct inode *inode, struct file *file)
137 {
138         if (test_and_set_bit(0, &rc32434_wdt_device.inuse))
139                 return -EBUSY;
140
141         if (nowayout)
142                 __module_get(THIS_MODULE);
143
144         return nonseekable_open(inode, file);
145 }
146
147 static int rc32434_wdt_release(struct inode *inode, struct file *file)
148 {
149         if (expect_close && nowayout == 0) {
150                 rc32434_wdt_stop();
151                 printk(KERN_INFO KBUILD_MODNAME ": disabling watchdog timer\n");
152                 module_put(THIS_MODULE);
153         } else
154                 printk(KERN_CRIT KBUILD_MODNAME
155                         ": device closed unexpectedly. WDT will not stop !\n");
156
157         clear_bit(0, &rc32434_wdt_device.inuse);
158         return 0;
159 }
160
161 static ssize_t rc32434_wdt_write(struct file *file, const char *data,
162                                 size_t len, loff_t *ppos)
163 {
164         if (len) {
165                 if (!nowayout) {
166                         size_t i;
167
168                         /* In case it was set long ago */
169                         expect_close = 0;
170
171                         for (i = 0; i != len; i++) {
172                                 char c;
173                                 if (get_user(c, data + i))
174                                         return -EFAULT;
175                                 if (c == 'V')
176                                         expect_close = 1;
177                         }
178                 }
179                 rc32434_wdt_update(0);
180                 return len;
181         }
182         return 0;
183 }
184
185 static int rc32434_wdt_ioctl(struct inode *inode, struct file *file,
186         unsigned int cmd, unsigned long arg)
187 {
188         void __user *argp = (void __user *)arg;
189         int new_timeout;
190         unsigned int value;
191         static struct watchdog_info ident = {
192                 .options =              WDIOF_SETTIMEOUT |
193                                         WDIOF_KEEPALIVEPING |
194                                         WDIOF_MAGICCLOSE,
195                 .identity =             "RC32434_WDT Watchdog",
196         };
197         switch (cmd) {
198         case WDIOC_KEEPALIVE:
199                 rc32434_wdt_reset();
200                 break;
201         case WDIOC_GETSTATUS:
202         case WDIOC_GETBOOTSTATUS:
203                 value = readl(&wdt_reg->wtcount);
204                 if (copy_to_user(argp, &value, sizeof(int)))
205                         return -EFAULT;
206                 break;
207         case WDIOC_GETSUPPORT:
208                 if (copy_to_user(argp, &ident, sizeof(ident)))
209                         return -EFAULT;
210                 break;
211         case WDIOC_SETOPTIONS:
212                 if (copy_from_user(&value, argp, sizeof(int)))
213                         return -EFAULT;
214                 switch (value) {
215                 case WDIOS_ENABLECARD:
216                         rc32434_wdt_start();
217                         break;
218                 case WDIOS_DISABLECARD:
219                         rc32434_wdt_stop();
220                 default:
221                         return -EINVAL;
222                 }
223                 break;
224         case WDIOC_SETTIMEOUT:
225                 if (copy_from_user(&new_timeout, argp, sizeof(int)))
226                         return -EFAULT;
227                 if (new_timeout < 1)
228                         return -EINVAL;
229                 if (new_timeout > MAX_TIMEOUT)
230                         return -EINVAL;
231                 rc32434_wdt_set(new_timeout);
232         case WDIOC_GETTIMEOUT:
233                 return copy_to_user(argp, &timeout, sizeof(int));
234         default:
235                 return -ENOTTY;
236         }
237
238         return 0;
239 }
240
241 static struct file_operations rc32434_wdt_fops = {
242         .owner          = THIS_MODULE,
243         .llseek         = no_llseek,
244         .write          = rc32434_wdt_write,
245         .ioctl          = rc32434_wdt_ioctl,
246         .open           = rc32434_wdt_open,
247         .release        = rc32434_wdt_release,
248 };
249
250 static struct miscdevice rc32434_wdt_miscdev = {
251         .minor  = WATCHDOG_MINOR,
252         .name   = "watchdog",
253         .fops   = &rc32434_wdt_fops,
254 };
255
256 static char banner[] = KERN_INFO KBUILD_MODNAME
257                 ": Watchdog Timer version " VERSION ", timer margin: %d sec\n";
258
259 static int rc32434_wdt_probe(struct platform_device *pdev)
260 {
261         int ret;
262         struct resource *r;
263
264         r = platform_get_resource_byname(pdev, IORESOURCE_MEM, "rb500_wdt_res");
265         if (!r) {
266                 printk(KERN_ERR KBUILD_MODNAME
267                         "failed to retrieve resources\n");
268                 return -ENODEV;
269         }
270
271         wdt_reg = ioremap_nocache(r->start, r->end - r->start);
272         if (!wdt_reg) {
273                 printk(KERN_ERR KBUILD_MODNAME
274                         "failed to remap I/O resources\n");
275                 return -ENXIO;
276         }
277
278         ret = misc_register(&rc32434_wdt_miscdev);
279
280         if (ret < 0) {
281                 printk(KERN_ERR KBUILD_MODNAME
282                         "failed to register watchdog device\n");
283                 goto unmap;
284         }
285
286         init_completion(&rc32434_wdt_device.stop);
287         rc32434_wdt_device.queue = 0;
288
289         clear_bit(0, &rc32434_wdt_device.inuse);
290
291         setup_timer(&rc32434_wdt_device.timer, rc32434_wdt_update, 0L);
292
293         rc32434_wdt_device.default_ticks = ticks;
294
295         rc32434_wdt_start();
296
297         printk(banner, timeout);
298
299         return 0;
300
301 unmap:
302         iounmap(wdt_reg);
303         return ret;
304 }
305
306 static int rc32434_wdt_remove(struct platform_device *pdev)
307 {
308         if (rc32434_wdt_device.queue) {
309                 rc32434_wdt_device.queue = 0;
310                 wait_for_completion(&rc32434_wdt_device.stop);
311         }
312         misc_deregister(&rc32434_wdt_miscdev);
313
314         iounmap(wdt_reg);
315
316         return 0;
317 }
318
319 static struct platform_driver rc32434_wdt = {
320         .probe  = rc32434_wdt_probe,
321         .remove = rc32434_wdt_remove,
322         .driver = {
323                 .name = "rc32434_wdt",
324         }
325 };
326
327 static int __init rc32434_wdt_init(void)
328 {
329         return platform_driver_register(&rc32434_wdt);
330 }
331
332 static void __exit rc32434_wdt_exit(void)
333 {
334         platform_driver_unregister(&rc32434_wdt);
335 }
336
337 module_init(rc32434_wdt_init);
338 module_exit(rc32434_wdt_exit);
339
340 MODULE_AUTHOR("Ondrej Zajicek <santiago@crfreenet.org>,"
341                 "Florian Fainelli <florian@openwrt.org>");
342 MODULE_DESCRIPTION("Driver for the IDT RC32434 SoC watchdog");
343 MODULE_LICENSE("GPL");
344 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);