[WATCHDOG] MIPS RM9000 on-chip watchdog device - patch 4
[sfrench/cifs-2.6.git] / drivers / char / 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 <asm/io.h>
33 #include <asm/atomic.h>
34 #include <asm/processor.h>
35 #include <asm/uaccess.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 *, struct pt_regs *);
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, loff_t *);
57 static long wdt_gpi_ioctl(struct file *, unsigned int, unsigned long);
58 static int wdt_gpi_notify(struct notifier_block *, unsigned long, void *);
59 static const struct resource *wdt_gpi_get_resource(struct platform_device *, const char *, unsigned int);
60 static int __init wdt_gpi_probe(struct device *);
61 static int __exit wdt_gpi_remove(struct device *);
62
63
64 static const char wdt_gpi_name[] = "wdt_gpi";
65 static atomic_t opencnt;
66 static int expect_close;
67 static int locked;
68
69
70 /* These are set from device resources */
71 static void __iomem * wd_regs;
72 static unsigned int wd_irq, wd_ctr;
73
74
75 /* Module arguments */
76 static int timeout = MAX_TIMEOUT_SECONDS;
77 module_param(timeout, int, 0444);
78 MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds");
79
80 static unsigned long resetaddr = 0xbffdc200;
81 module_param(resetaddr, ulong, 0444);
82 MODULE_PARM_DESC(resetaddr, "Address to write to to force a reset");
83
84 static unsigned long flagaddr = 0xbffdc104;
85 module_param(flagaddr, ulong, 0444);
86 MODULE_PARM_DESC(flagaddr, "Address to write to boot flags to");
87
88 static int powercycle;
89 module_param(powercycle, bool, 0444);
90 MODULE_PARM_DESC(powercycle, "Cycle power if watchdog expires");
91
92 static int nowayout = WATCHDOG_NOWAYOUT;
93 module_param(nowayout, bool, 0444);
94 MODULE_PARM_DESC(nowayout, "Watchdog cannot be disabled once started");
95
96
97 /* Interrupt handler */
98 static irqreturn_t wdt_gpi_irqhdl(int irq, void *ctxt, struct pt_regs *regs)
99 {
100         if (!unlikely(__raw_readl(wd_regs + 0x0008) & 0x1))
101                 return IRQ_NONE;
102         __raw_writel(0x1, wd_regs + 0x0008);
103
104
105         printk(KERN_CRIT "%s: watchdog expired - resetting system\n",
106                 wdt_gpi_name);
107
108         *(volatile char *) flagaddr |= 0x01;
109         *(volatile char *) resetaddr = powercycle ? 0x01 : 0x2;
110         iob();
111         while (1)
112                 cpu_relax();
113 }
114
115
116 /* Watchdog functions */
117 static void wdt_gpi_start(void)
118 {
119         u32 reg;
120
121         lock_titan_regs();
122         reg = titan_readl(CPGIG1ER);
123         titan_writel(reg | (0x100 << wd_ctr), CPGIG1ER);
124         iob();
125         unlock_titan_regs();
126 }
127
128 static void wdt_gpi_stop(void)
129 {
130         u32 reg;
131
132         lock_titan_regs();
133         reg = titan_readl(CPCCR) & ~(0xf << (wd_ctr * 4));
134         titan_writel(reg, CPCCR);
135         reg = titan_readl(CPGIG1ER);
136         titan_writel(reg & ~(0x100 << wd_ctr), CPGIG1ER);
137         iob();
138         unlock_titan_regs();
139 }
140
141 static void wdt_gpi_set_timeout(unsigned int to)
142 {
143         u32 reg;
144         const u32 wdval = (to * CLOCK) & ~0x0000000f;
145
146         lock_titan_regs();
147         reg = titan_readl(CPCCR) & ~(0xf << (wd_ctr * 4));
148         titan_writel(reg, CPCCR);
149         wmb();
150         __raw_writel(wdval, wd_regs + 0x0000);
151         wmb();
152         titan_writel(reg | (0x2 << (wd_ctr * 4)), CPCCR);
153         wmb();
154         titan_writel(reg | (0x5 << (wd_ctr * 4)), CPCCR);
155         iob();
156         unlock_titan_regs();
157 }
158
159
160 /* /dev/watchdog operations */
161 static int wdt_gpi_open(struct inode *inode, struct file *file)
162 {
163         int res;
164
165         if (unlikely(atomic_dec_if_positive(&opencnt) < 0))
166                 return -EBUSY;
167
168         expect_close = 0;
169         if (locked) {
170                 module_put(THIS_MODULE);
171                 free_irq(wd_irq, &miscdev);
172                 locked = 0;
173         }
174
175         res = request_irq(wd_irq, wdt_gpi_irqhdl, SA_SHIRQ | SA_INTERRUPT,
176                           wdt_gpi_name, &miscdev);
177         if (unlikely(res))
178                 return res;
179
180         wdt_gpi_set_timeout(timeout);
181         wdt_gpi_start();
182
183         printk(KERN_INFO "%s: watchdog started, timeout = %u seconds\n",
184                 wdt_gpi_name, timeout);
185         return nonseekable_open(inode, file);
186 }
187
188 static int wdt_gpi_release(struct inode *inode, struct file *file)
189 {
190         if (nowayout) {
191                 printk(KERN_INFO "%s: no way out - watchdog left running\n",
192                         wdt_gpi_name);
193                 __module_get(THIS_MODULE);
194                 locked = 1;
195         } else {
196                 if (expect_close) {
197                         wdt_gpi_stop();
198                         free_irq(wd_irq, &miscdev);
199                         printk(KERN_INFO "%s: watchdog stopped\n", wdt_gpi_name);
200                 } else {
201                         printk(KERN_CRIT "%s: unexpected close() -"
202                                 " watchdog left running\n",
203                                 wdt_gpi_name);
204                         wdt_gpi_set_timeout(timeout);
205                         __module_get(THIS_MODULE);
206                         locked = 1;
207                 }
208         }
209
210         atomic_inc(&opencnt);
211         return 0;
212 }
213
214 static ssize_t
215 wdt_gpi_write(struct file *f, const char __user *d, size_t s, loff_t *o)
216 {
217         char val;
218
219         wdt_gpi_set_timeout(timeout);
220         expect_close = (s > 0) && !get_user(val, d) && (val == 'V');
221         return s ? 1 : 0;
222 }
223
224 static long
225 wdt_gpi_ioctl(struct file *f, unsigned int cmd, unsigned long arg)
226 {
227         long res = -ENOTTY;
228         const long size = _IOC_SIZE(cmd);
229         int stat;
230         void __user *argp = (void __user *)arg;
231         static struct watchdog_info wdinfo = {
232                 .identity               = "RM9xxx/GPI watchdog",
233                 .firmware_version       = 0,
234                 .options                = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING
235         };
236
237         if (unlikely(_IOC_TYPE(cmd) != WATCHDOG_IOCTL_BASE))
238                 return -ENOTTY;
239
240         if ((_IOC_DIR(cmd) & _IOC_READ)
241             && !access_ok(VERIFY_WRITE, arg, size))
242                 return -EFAULT;
243
244         if ((_IOC_DIR(cmd) & _IOC_WRITE)
245             && !access_ok(VERIFY_READ, arg, size))
246                 return -EFAULT;
247
248         expect_close = 0;
249
250         switch (cmd) {
251         case WDIOC_GETSUPPORT:
252                 wdinfo.options = nowayout ?
253                         WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING :
254                         WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE;
255                 res = __copy_to_user(argp, &wdinfo, size) ?  -EFAULT : size;
256                 break;
257
258         case WDIOC_GETSTATUS:
259                 break;
260
261         case WDIOC_GETBOOTSTATUS:
262                 stat = (*(volatile char *) flagaddr & 0x01)
263                         ? WDIOF_CARDRESET : 0;
264                 res = __copy_to_user(argp, &stat, size) ?
265                         -EFAULT : size;
266                 break;
267
268         case WDIOC_SETOPTIONS:
269                 break;
270
271         case WDIOC_KEEPALIVE:
272                 wdt_gpi_set_timeout(timeout);
273                 res = size;
274                 break;
275
276         case WDIOC_SETTIMEOUT:
277                 {
278                         int val;
279                         if (unlikely(__copy_from_user(&val, argp, size))) {
280                                 res = -EFAULT;
281                                 break;
282                         }
283
284                         if (val > MAX_TIMEOUT_SECONDS)
285                                 val = MAX_TIMEOUT_SECONDS;
286                         timeout = val;
287                         wdt_gpi_set_timeout(val);
288                         res = size;
289                         printk(KERN_INFO "%s: timeout set to %u seconds\n",
290                                 wdt_gpi_name, timeout);
291                 }
292                 break;
293
294         case WDIOC_GETTIMEOUT:
295                 res = __copy_to_user(argp, &timeout, size) ?
296                         -EFAULT : size;
297                 break;
298         }
299
300         return res;
301 }
302
303
304 /* Shutdown notifier */
305 static int
306 wdt_gpi_notify(struct notifier_block *this, unsigned long code, void *unused)
307 {
308         if (code == SYS_DOWN || code == SYS_HALT)
309                 wdt_gpi_stop();
310
311         return NOTIFY_DONE;
312 }
313
314
315 /* Kernel interfaces */
316 static struct file_operations fops = {
317         .owner          = THIS_MODULE,
318         .open           = wdt_gpi_open,
319         .release        = wdt_gpi_release,
320         .write          = wdt_gpi_write,
321         .unlocked_ioctl = wdt_gpi_ioctl,
322 };
323
324 static struct miscdevice miscdev = {
325         .minor          = WATCHDOG_MINOR,
326         .name           = wdt_gpi_name,
327         .fops           = &fops,
328 };
329
330 static struct notifier_block wdt_gpi_shutdown = {
331         .notifier_call  = wdt_gpi_notify,
332 };
333
334
335 /* Init & exit procedures */
336 static const struct resource *
337 wdt_gpi_get_resource(struct platform_device *pdv, const char *name,
338                       unsigned int type)
339 {
340         char buf[80];
341         if (snprintf(buf, sizeof buf, "%s_0", name) >= sizeof buf)
342                 return NULL;
343         return platform_get_resource_byname(pdv, type, buf);
344 }
345
346 /* No hotplugging on the platform bus - use __init */
347 static int __init wdt_gpi_probe(struct device *dev)
348 {
349         int res;
350         struct platform_device * const pdv = to_platform_device(dev);
351         const struct resource
352                 * const rr = wdt_gpi_get_resource(pdv, WDT_RESOURCE_REGS,
353                                                   IORESOURCE_MEM),
354                 * const ri = wdt_gpi_get_resource(pdv, WDT_RESOURCE_IRQ,
355                                                   IORESOURCE_IRQ),
356                 * const rc = wdt_gpi_get_resource(pdv, WDT_RESOURCE_COUNTER,
357                                                   0);
358
359         if (unlikely(!rr || !ri || !rc))
360                 return -ENXIO;
361
362         wd_regs = ioremap_nocache(rr->start, rr->end + 1 - rr->start);
363         if (unlikely(!wd_regs))
364                 return -ENOMEM;
365         wd_irq = ri->start;
366         wd_ctr = rc->start;
367         res = misc_register(&miscdev);
368         if (res)
369                 iounmap(wd_regs);
370         else
371                 register_reboot_notifier(&wdt_gpi_shutdown);
372         return res;
373 }
374
375 static int __exit wdt_gpi_remove(struct device *dev)
376 {
377         int res;
378
379         unregister_reboot_notifier(&wdt_gpi_shutdown);
380         res = misc_deregister(&miscdev);
381         iounmap(wd_regs);
382         wd_regs = NULL;
383         return res;
384 }
385
386
387 /* Device driver init & exit */
388 static struct device_driver wdt_gpi_driver = {
389         .name           = (char *) wdt_gpi_name,
390         .bus            = &platform_bus_type,
391         .owner          = THIS_MODULE,
392         .probe          = wdt_gpi_probe,
393         .remove         = __exit_p(wdt_gpi_remove),
394         .shutdown       = NULL,
395         .suspend        = NULL,
396         .resume         = NULL,
397 };
398
399 static int __init wdt_gpi_init_module(void)
400 {
401         atomic_set(&opencnt, 1);
402         if (timeout > MAX_TIMEOUT_SECONDS)
403                 timeout = MAX_TIMEOUT_SECONDS;
404         return driver_register(&wdt_gpi_driver);
405 }
406
407 static void __exit wdt_gpi_cleanup_module(void)
408 {
409         driver_unregister(&wdt_gpi_driver);
410 }
411
412 module_init(wdt_gpi_init_module);
413 module_exit(wdt_gpi_cleanup_module);
414
415 MODULE_AUTHOR("Thomas Koeller <thomas.koeller@baslerweb.com>");
416 MODULE_DESCRIPTION("Basler eXcite watchdog driver for gpi devices");
417 MODULE_VERSION("0.1");
418 MODULE_LICENSE("GPL");
419 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
420