[WATCHDOG] more coding style clean-up's
[linux-2.6.git] / drivers / watchdog / rm9k_wdt.c
1 /*
2  *  Watchdog implementation for GPI h/w found on PMC-Sierra RM9xxx
3  *  chips.
4  *
5  *  Copyright (C) 2004 by Basler Vision Technologies AG
6  *  Author: Thomas Koeller <thomas.koeller@baslerweb.com>
7  *
8  *  This program is free software; you can redistribute it and/or modify
9  *  it under the terms of the GNU General Public License as published by
10  *  the Free Software Foundation; either version 2 of the License, or
11  *  (at your option) any later version.
12  *
13  *  This program is distributed in the hope that it will be useful,
14  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
15  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16  *  GNU General Public License for more details.
17  *
18  *  You should have received a copy of the GNU General Public License
19  *  along with this program; if not, write to the Free Software
20  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
21  */
22
23 #include <linux/platform_device.h>
24 #include <linux/module.h>
25 #include <linux/moduleparam.h>
26 #include <linux/interrupt.h>
27 #include <linux/fs.h>
28 #include <linux/reboot.h>
29 #include <linux/notifier.h>
30 #include <linux/miscdevice.h>
31 #include <linux/watchdog.h>
32 #include <linux/io.h>
33 #include <linux/uaccess.h>
34 #include <asm/atomic.h>
35 #include <asm/processor.h>
36 #include <asm/system.h>
37 #include <asm/rm9k-ocd.h>
38
39 #include <rm9k_wdt.h>
40
41
42 #define CLOCK                  125000000
43 #define MAX_TIMEOUT_SECONDS    32
44 #define CPCCR                  0x0080
45 #define CPGIG1SR               0x0044
46 #define CPGIG1ER               0x0054
47
48
49 /* Function prototypes */
50 static irqreturn_t wdt_gpi_irqhdl(int, void *);
51 static void wdt_gpi_start(void);
52 static void wdt_gpi_stop(void);
53 static void wdt_gpi_set_timeout(unsigned int);
54 static int wdt_gpi_open(struct inode *, struct file *);
55 static int wdt_gpi_release(struct inode *, struct file *);
56 static ssize_t wdt_gpi_write(struct file *, const char __user *, size_t,
57                                                                 loff_t *);
58 static long wdt_gpi_ioctl(struct file *, unsigned int, unsigned long);
59 static int wdt_gpi_notify(struct notifier_block *, unsigned long, void *);
60 static const struct resource *wdt_gpi_get_resource(struct platform_device *,
61                                                 const char *, unsigned int);
62 static int __init wdt_gpi_probe(struct device *);
63 static int __exit wdt_gpi_remove(struct device *);
64
65
66 static const char wdt_gpi_name[] = "wdt_gpi";
67 static atomic_t opencnt;
68 static int expect_close;
69 static int locked;
70
71
72 /* These are set from device resources */
73 static void __iomem *wd_regs;
74 static unsigned int wd_irq, wd_ctr;
75
76
77 /* Module arguments */
78 static int timeout = MAX_TIMEOUT_SECONDS;
79 module_param(timeout, int, 0444);
80 MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds");
81
82 static unsigned long resetaddr = 0xbffdc200;
83 module_param(resetaddr, ulong, 0444);
84 MODULE_PARM_DESC(resetaddr, "Address to write to to force a reset");
85
86 static unsigned long flagaddr = 0xbffdc104;
87 module_param(flagaddr, ulong, 0444);
88 MODULE_PARM_DESC(flagaddr, "Address to write to boot flags to");
89
90 static int powercycle;
91 module_param(powercycle, bool, 0444);
92 MODULE_PARM_DESC(powercycle, "Cycle power if watchdog expires");
93
94 static int nowayout = WATCHDOG_NOWAYOUT;
95 module_param(nowayout, bool, 0444);
96 MODULE_PARM_DESC(nowayout, "Watchdog cannot be disabled once started");
97
98
99 /* Kernel interfaces */
100 static const struct file_operations fops = {
101         .owner          = THIS_MODULE,
102         .open           = wdt_gpi_open,
103         .release        = wdt_gpi_release,
104         .write          = wdt_gpi_write,
105         .unlocked_ioctl = wdt_gpi_ioctl,
106 };
107
108 static struct miscdevice miscdev = {
109         .minor          = WATCHDOG_MINOR,
110         .name           = wdt_gpi_name,
111         .fops           = &fops,
112 };
113
114 static struct notifier_block wdt_gpi_shutdown = {
115         .notifier_call  = wdt_gpi_notify,
116 };
117
118
119 /* Interrupt handler */
120 static irqreturn_t wdt_gpi_irqhdl(int irq, void *ctxt)
121 {
122         if (!unlikely(__raw_readl(wd_regs + 0x0008) & 0x1))
123                 return IRQ_NONE;
124         __raw_writel(0x1, wd_regs + 0x0008);
125
126
127         printk(KERN_CRIT "%s: watchdog expired - resetting system\n",
128                 wdt_gpi_name);
129
130         *(volatile char *) flagaddr |= 0x01;
131         *(volatile char *) resetaddr = powercycle ? 0x01 : 0x2;
132         iob();
133         while (1)
134                 cpu_relax();
135 }
136
137
138 /* Watchdog functions */
139 static void wdt_gpi_start(void)
140 {
141         u32 reg;
142
143         lock_titan_regs();
144         reg = titan_readl(CPGIG1ER);
145         titan_writel(reg | (0x100 << wd_ctr), CPGIG1ER);
146         iob();
147         unlock_titan_regs();
148 }
149
150 static void wdt_gpi_stop(void)
151 {
152         u32 reg;
153
154         lock_titan_regs();
155         reg = titan_readl(CPCCR) & ~(0xf << (wd_ctr * 4));
156         titan_writel(reg, CPCCR);
157         reg = titan_readl(CPGIG1ER);
158         titan_writel(reg & ~(0x100 << wd_ctr), CPGIG1ER);
159         iob();
160         unlock_titan_regs();
161 }
162
163 static void wdt_gpi_set_timeout(unsigned int to)
164 {
165         u32 reg;
166         const u32 wdval = (to * CLOCK) & ~0x0000000f;
167
168         lock_titan_regs();
169         reg = titan_readl(CPCCR) & ~(0xf << (wd_ctr * 4));
170         titan_writel(reg, CPCCR);
171         wmb();
172         __raw_writel(wdval, wd_regs + 0x0000);
173         wmb();
174         titan_writel(reg | (0x2 << (wd_ctr * 4)), CPCCR);
175         wmb();
176         titan_writel(reg | (0x5 << (wd_ctr * 4)), CPCCR);
177         iob();
178         unlock_titan_regs();
179 }
180
181
182 /* /dev/watchdog operations */
183 static int wdt_gpi_open(struct inode *inode, struct file *file)
184 {
185         int res;
186
187         if (unlikely(atomic_dec_if_positive(&opencnt) < 0))
188                 return -EBUSY;
189
190         expect_close = 0;
191         if (locked) {
192                 module_put(THIS_MODULE);
193                 free_irq(wd_irq, &miscdev);
194                 locked = 0;
195         }
196
197         res = request_irq(wd_irq, wdt_gpi_irqhdl, IRQF_SHARED | IRQF_DISABLED,
198                           wdt_gpi_name, &miscdev);
199         if (unlikely(res))
200                 return res;
201
202         wdt_gpi_set_timeout(timeout);
203         wdt_gpi_start();
204
205         printk(KERN_INFO "%s: watchdog started, timeout = %u seconds\n",
206                 wdt_gpi_name, timeout);
207         return nonseekable_open(inode, file);
208 }
209
210 static int wdt_gpi_release(struct inode *inode, struct file *file)
211 {
212         if (nowayout) {
213                 printk(KERN_INFO "%s: no way out - watchdog left running\n",
214                         wdt_gpi_name);
215                 __module_get(THIS_MODULE);
216                 locked = 1;
217         } else {
218                 if (expect_close) {
219                         wdt_gpi_stop();
220                         free_irq(wd_irq, &miscdev);
221                         printk(KERN_INFO "%s: watchdog stopped\n",
222                                                         wdt_gpi_name);
223                 } else {
224                         printk(KERN_CRIT "%s: unexpected close() -"
225                                 " watchdog left running\n",
226                                 wdt_gpi_name);
227                         wdt_gpi_set_timeout(timeout);
228                         __module_get(THIS_MODULE);
229                         locked = 1;
230                 }
231         }
232
233         atomic_inc(&opencnt);
234         return 0;
235 }
236
237 static ssize_t wdt_gpi_write(struct file *f, const char __user *d, size_t s,
238                                                                 loff_t *o)
239 {
240         char val;
241
242         wdt_gpi_set_timeout(timeout);
243         expect_close = (s > 0) && !get_user(val, d) && (val == 'V');
244         return s ? 1 : 0;
245 }
246
247 static long wdt_gpi_ioctl(struct file *f, unsigned int cmd, unsigned long arg)
248 {
249         long res = -ENOTTY;
250         const long size = _IOC_SIZE(cmd);
251         int stat;
252         void __user *argp = (void __user *)arg;
253         static struct watchdog_info wdinfo = {
254                 .identity               = "RM9xxx/GPI watchdog",
255                 .firmware_version       = 0,
256                 .options                = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING
257         };
258
259         if (unlikely(_IOC_TYPE(cmd) != WATCHDOG_IOCTL_BASE))
260                 return -ENOTTY;
261
262         if ((_IOC_DIR(cmd) & _IOC_READ)
263             && !access_ok(VERIFY_WRITE, arg, size))
264                 return -EFAULT;
265
266         if ((_IOC_DIR(cmd) & _IOC_WRITE)
267             && !access_ok(VERIFY_READ, arg, size))
268                 return -EFAULT;
269
270         expect_close = 0;
271
272         switch (cmd) {
273         case WDIOC_GETSUPPORT:
274                 wdinfo.options = nowayout ?
275                         WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING :
276                         WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
277                         WDIOF_MAGICCLOSE;
278                 res = __copy_to_user(argp, &wdinfo, size) ?  -EFAULT : size;
279                 break;
280
281         case WDIOC_GETSTATUS:
282                 break;
283
284         case WDIOC_GETBOOTSTATUS:
285                 stat = (*(volatile char *) flagaddr & 0x01)
286                         ? WDIOF_CARDRESET : 0;
287                 res = __copy_to_user(argp, &stat, size) ?
288                         -EFAULT : size;
289                 break;
290
291         case WDIOC_SETOPTIONS:
292                 break;
293
294         case WDIOC_KEEPALIVE:
295                 wdt_gpi_set_timeout(timeout);
296                 res = size;
297                 break;
298
299         case WDIOC_SETTIMEOUT:
300                 {
301                         int val;
302                         if (unlikely(__copy_from_user(&val, argp, size))) {
303                                 res = -EFAULT;
304                                 break;
305                         }
306
307                         if (val > MAX_TIMEOUT_SECONDS)
308                                 val = MAX_TIMEOUT_SECONDS;
309                         timeout = val;
310                         wdt_gpi_set_timeout(val);
311                         res = size;
312                         printk(KERN_INFO "%s: timeout set to %u seconds\n",
313                                 wdt_gpi_name, timeout);
314                 }
315                 break;
316
317         case WDIOC_GETTIMEOUT:
318                 res = __copy_to_user(argp, &timeout, size) ?
319                         -EFAULT : size;
320                 break;
321         }
322
323         return res;
324 }
325
326
327 /* Shutdown notifier */
328 static int wdt_gpi_notify(struct notifier_block *this, unsigned long code,
329                           void *unused)
330 {
331         if (code == SYS_DOWN || code == SYS_HALT)
332                 wdt_gpi_stop();
333
334         return NOTIFY_DONE;
335 }
336
337
338 /* Init & exit procedures */
339 static const struct resource *wdt_gpi_get_resource(struct platform_device *pdv,
340                                         const char *name, unsigned int type)
341 {
342         char buf[80];
343         if (snprintf(buf, sizeof buf, "%s_0", name) >= sizeof buf)
344                 return NULL;
345         return platform_get_resource_byname(pdv, type, buf);
346 }
347
348 /* No hotplugging on the platform bus - use __init */
349 static int __init wdt_gpi_probe(struct device *dev)
350 {
351         int res;
352         struct platform_device * const pdv = to_platform_device(dev);
353         const struct resource
354                 * const rr = wdt_gpi_get_resource(pdv, WDT_RESOURCE_REGS,
355                                                   IORESOURCE_MEM),
356                 * const ri = wdt_gpi_get_resource(pdv, WDT_RESOURCE_IRQ,
357                                                   IORESOURCE_IRQ),
358                 * const rc = wdt_gpi_get_resource(pdv, WDT_RESOURCE_COUNTER,
359                                                   0);
360
361         if (unlikely(!rr || !ri || !rc))
362                 return -ENXIO;
363
364         wd_regs = ioremap_nocache(rr->start, rr->end + 1 - rr->start);
365         if (unlikely(!wd_regs))
366                 return -ENOMEM;
367         wd_irq = ri->start;
368         wd_ctr = rc->start;
369         res = misc_register(&miscdev);
370         if (res)
371                 iounmap(wd_regs);
372         else
373                 register_reboot_notifier(&wdt_gpi_shutdown);
374         return res;
375 }
376
377 static int __exit wdt_gpi_remove(struct device *dev)
378 {
379         int res;
380
381         unregister_reboot_notifier(&wdt_gpi_shutdown);
382         res = misc_deregister(&miscdev);
383         iounmap(wd_regs);
384         wd_regs = NULL;
385         return res;
386 }
387
388
389 /* Device driver init & exit */
390 static struct device_driver wdt_gpi_driver = {
391         .name           = (char *) wdt_gpi_name,
392         .bus            = &platform_bus_type,
393         .owner          = THIS_MODULE,
394         .probe          = wdt_gpi_probe,
395         .remove         = __exit_p(wdt_gpi_remove),
396         .shutdown       = NULL,
397         .suspend        = NULL,
398         .resume         = NULL,
399 };
400
401 static int __init wdt_gpi_init_module(void)
402 {
403         atomic_set(&opencnt, 1);
404         if (timeout > MAX_TIMEOUT_SECONDS)
405                 timeout = MAX_TIMEOUT_SECONDS;
406         return driver_register(&wdt_gpi_driver);
407 }
408
409 static void __exit wdt_gpi_cleanup_module(void)
410 {
411         driver_unregister(&wdt_gpi_driver);
412 }
413
414 module_init(wdt_gpi_init_module);
415 module_exit(wdt_gpi_cleanup_module);
416
417 MODULE_AUTHOR("Thomas Koeller <thomas.koeller@baslerweb.com>");
418 MODULE_DESCRIPTION("Basler eXcite watchdog driver for gpi devices");
419 MODULE_VERSION("0.1");
420 MODULE_LICENSE("GPL");
421 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
422