libata-link: update EH to deal with PMP links
[linux-2.6] / 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 *);
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 /* Kernel interfaces */
98 static const struct file_operations fops = {
99         .owner          = THIS_MODULE,
100         .open           = wdt_gpi_open,
101         .release        = wdt_gpi_release,
102         .write          = wdt_gpi_write,
103         .unlocked_ioctl = wdt_gpi_ioctl,
104 };
105
106 static struct miscdevice miscdev = {
107         .minor          = WATCHDOG_MINOR,
108         .name           = wdt_gpi_name,
109         .fops           = &fops,
110 };
111
112 static struct notifier_block wdt_gpi_shutdown = {
113         .notifier_call  = wdt_gpi_notify,
114 };
115
116
117 /* Interrupt handler */
118 static irqreturn_t wdt_gpi_irqhdl(int irq, void *ctxt)
119 {
120         if (!unlikely(__raw_readl(wd_regs + 0x0008) & 0x1))
121                 return IRQ_NONE;
122         __raw_writel(0x1, wd_regs + 0x0008);
123
124
125         printk(KERN_CRIT "%s: watchdog expired - resetting system\n",
126                 wdt_gpi_name);
127
128         *(volatile char *) flagaddr |= 0x01;
129         *(volatile char *) resetaddr = powercycle ? 0x01 : 0x2;
130         iob();
131         while (1)
132                 cpu_relax();
133 }
134
135
136 /* Watchdog functions */
137 static void wdt_gpi_start(void)
138 {
139         u32 reg;
140
141         lock_titan_regs();
142         reg = titan_readl(CPGIG1ER);
143         titan_writel(reg | (0x100 << wd_ctr), CPGIG1ER);
144         iob();
145         unlock_titan_regs();
146 }
147
148 static void wdt_gpi_stop(void)
149 {
150         u32 reg;
151
152         lock_titan_regs();
153         reg = titan_readl(CPCCR) & ~(0xf << (wd_ctr * 4));
154         titan_writel(reg, CPCCR);
155         reg = titan_readl(CPGIG1ER);
156         titan_writel(reg & ~(0x100 << wd_ctr), CPGIG1ER);
157         iob();
158         unlock_titan_regs();
159 }
160
161 static void wdt_gpi_set_timeout(unsigned int to)
162 {
163         u32 reg;
164         const u32 wdval = (to * CLOCK) & ~0x0000000f;
165
166         lock_titan_regs();
167         reg = titan_readl(CPCCR) & ~(0xf << (wd_ctr * 4));
168         titan_writel(reg, CPCCR);
169         wmb();
170         __raw_writel(wdval, wd_regs + 0x0000);
171         wmb();
172         titan_writel(reg | (0x2 << (wd_ctr * 4)), CPCCR);
173         wmb();
174         titan_writel(reg | (0x5 << (wd_ctr * 4)), CPCCR);
175         iob();
176         unlock_titan_regs();
177 }
178
179
180 /* /dev/watchdog operations */
181 static int wdt_gpi_open(struct inode *inode, struct file *file)
182 {
183         int res;
184
185         if (unlikely(atomic_dec_if_positive(&opencnt) < 0))
186                 return -EBUSY;
187
188         expect_close = 0;
189         if (locked) {
190                 module_put(THIS_MODULE);
191                 free_irq(wd_irq, &miscdev);
192                 locked = 0;
193         }
194
195         res = request_irq(wd_irq, wdt_gpi_irqhdl, IRQF_SHARED | IRQF_DISABLED,
196                           wdt_gpi_name, &miscdev);
197         if (unlikely(res))
198                 return res;
199
200         wdt_gpi_set_timeout(timeout);
201         wdt_gpi_start();
202
203         printk(KERN_INFO "%s: watchdog started, timeout = %u seconds\n",
204                 wdt_gpi_name, timeout);
205         return nonseekable_open(inode, file);
206 }
207
208 static int wdt_gpi_release(struct inode *inode, struct file *file)
209 {
210         if (nowayout) {
211                 printk(KERN_INFO "%s: no way out - watchdog left running\n",
212                         wdt_gpi_name);
213                 __module_get(THIS_MODULE);
214                 locked = 1;
215         } else {
216                 if (expect_close) {
217                         wdt_gpi_stop();
218                         free_irq(wd_irq, &miscdev);
219                         printk(KERN_INFO "%s: watchdog stopped\n", wdt_gpi_name);
220                 } else {
221                         printk(KERN_CRIT "%s: unexpected close() -"
222                                 " watchdog left running\n",
223                                 wdt_gpi_name);
224                         wdt_gpi_set_timeout(timeout);
225                         __module_get(THIS_MODULE);
226                         locked = 1;
227                 }
228         }
229
230         atomic_inc(&opencnt);
231         return 0;
232 }
233
234 static ssize_t
235 wdt_gpi_write(struct file *f, const char __user *d, size_t s, loff_t *o)
236 {
237         char val;
238
239         wdt_gpi_set_timeout(timeout);
240         expect_close = (s > 0) && !get_user(val, d) && (val == 'V');
241         return s ? 1 : 0;
242 }
243
244 static long
245 wdt_gpi_ioctl(struct file *f, unsigned int cmd, unsigned long arg)
246 {
247         long res = -ENOTTY;
248         const long size = _IOC_SIZE(cmd);
249         int stat;
250         void __user *argp = (void __user *)arg;
251         static struct watchdog_info wdinfo = {
252                 .identity               = "RM9xxx/GPI watchdog",
253                 .firmware_version       = 0,
254                 .options                = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING
255         };
256
257         if (unlikely(_IOC_TYPE(cmd) != WATCHDOG_IOCTL_BASE))
258                 return -ENOTTY;
259
260         if ((_IOC_DIR(cmd) & _IOC_READ)
261             && !access_ok(VERIFY_WRITE, arg, size))
262                 return -EFAULT;
263
264         if ((_IOC_DIR(cmd) & _IOC_WRITE)
265             && !access_ok(VERIFY_READ, arg, size))
266                 return -EFAULT;
267
268         expect_close = 0;
269
270         switch (cmd) {
271         case WDIOC_GETSUPPORT:
272                 wdinfo.options = nowayout ?
273                         WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING :
274                         WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE;
275                 res = __copy_to_user(argp, &wdinfo, size) ?  -EFAULT : size;
276                 break;
277
278         case WDIOC_GETSTATUS:
279                 break;
280
281         case WDIOC_GETBOOTSTATUS:
282                 stat = (*(volatile char *) flagaddr & 0x01)
283                         ? WDIOF_CARDRESET : 0;
284                 res = __copy_to_user(argp, &stat, size) ?
285                         -EFAULT : size;
286                 break;
287
288         case WDIOC_SETOPTIONS:
289                 break;
290
291         case WDIOC_KEEPALIVE:
292                 wdt_gpi_set_timeout(timeout);
293                 res = size;
294                 break;
295
296         case WDIOC_SETTIMEOUT:
297                 {
298                         int val;
299                         if (unlikely(__copy_from_user(&val, argp, size))) {
300                                 res = -EFAULT;
301                                 break;
302                         }
303
304                         if (val > MAX_TIMEOUT_SECONDS)
305                                 val = MAX_TIMEOUT_SECONDS;
306                         timeout = val;
307                         wdt_gpi_set_timeout(val);
308                         res = size;
309                         printk(KERN_INFO "%s: timeout set to %u seconds\n",
310                                 wdt_gpi_name, timeout);
311                 }
312                 break;
313
314         case WDIOC_GETTIMEOUT:
315                 res = __copy_to_user(argp, &timeout, size) ?
316                         -EFAULT : size;
317                 break;
318         }
319
320         return res;
321 }
322
323
324 /* Shutdown notifier */
325 static int
326 wdt_gpi_notify(struct notifier_block *this, unsigned long code, void *unused)
327 {
328         if (code == SYS_DOWN || code == SYS_HALT)
329                 wdt_gpi_stop();
330
331         return NOTIFY_DONE;
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