switch lookup_mnt()
[linux-2.6.git] / drivers / watchdog / omap_wdt.c
1 /*
2  * omap_wdt.c
3  *
4  * Watchdog driver for the TI OMAP 16xx & 24xx/34xx 32KHz (non-secure) watchdog
5  *
6  * Author: MontaVista Software, Inc.
7  *       <gdavis@mvista.com> or <source@mvista.com>
8  *
9  * 2003 (c) MontaVista Software, Inc. This file is licensed under the
10  * terms of the GNU General Public License version 2. This program is
11  * licensed "as is" without any warranty of any kind, whether express
12  * or implied.
13  *
14  * History:
15  *
16  * 20030527: George G. Davis <gdavis@mvista.com>
17  *      Initially based on linux-2.4.19-rmk7-pxa1/drivers/char/sa1100_wdt.c
18  *      (c) Copyright 2000 Oleg Drokin <green@crimea.edu>
19  *      Based on SoftDog driver by Alan Cox <alan@lxorguk.ukuu.org.uk>
20  *
21  * Copyright (c) 2004 Texas Instruments.
22  *      1. Modified to support OMAP1610 32-KHz watchdog timer
23  *      2. Ported to 2.6 kernel
24  *
25  * Copyright (c) 2005 David Brownell
26  *      Use the driver model and standard identifiers; handle bigger timeouts.
27  */
28
29 #include <linux/module.h>
30 #include <linux/types.h>
31 #include <linux/kernel.h>
32 #include <linux/fs.h>
33 #include <linux/mm.h>
34 #include <linux/miscdevice.h>
35 #include <linux/watchdog.h>
36 #include <linux/reboot.h>
37 #include <linux/init.h>
38 #include <linux/err.h>
39 #include <linux/platform_device.h>
40 #include <linux/moduleparam.h>
41 #include <linux/clk.h>
42 #include <linux/bitops.h>
43 #include <linux/io.h>
44 #include <linux/uaccess.h>
45 #include <mach/hardware.h>
46 #include <mach/prcm.h>
47
48 #include "omap_wdt.h"
49
50 static struct platform_device *omap_wdt_dev;
51
52 static unsigned timer_margin;
53 module_param(timer_margin, uint, 0);
54 MODULE_PARM_DESC(timer_margin, "initial watchdog timeout (in seconds)");
55
56 static unsigned int wdt_trgr_pattern = 0x1234;
57 static spinlock_t wdt_lock;
58
59 struct omap_wdt_dev {
60         void __iomem    *base;          /* physical */
61         struct device   *dev;
62         int             omap_wdt_users;
63         struct clk      *ick;
64         struct clk      *fck;
65         struct resource *mem;
66         struct miscdevice omap_wdt_miscdev;
67 };
68
69 static void omap_wdt_ping(struct omap_wdt_dev *wdev)
70 {
71         void __iomem    *base = wdev->base;
72
73         /* wait for posted write to complete */
74         while ((__raw_readl(base + OMAP_WATCHDOG_WPS)) & 0x08)
75                 cpu_relax();
76
77         wdt_trgr_pattern = ~wdt_trgr_pattern;
78         __raw_writel(wdt_trgr_pattern, (base + OMAP_WATCHDOG_TGR));
79
80         /* wait for posted write to complete */
81         while ((__raw_readl(base + OMAP_WATCHDOG_WPS)) & 0x08)
82                 cpu_relax();
83         /* reloaded WCRR from WLDR */
84 }
85
86 static void omap_wdt_enable(struct omap_wdt_dev *wdev)
87 {
88         void __iomem *base = wdev->base;
89
90         /* Sequence to enable the watchdog */
91         __raw_writel(0xBBBB, base + OMAP_WATCHDOG_SPR);
92         while ((__raw_readl(base + OMAP_WATCHDOG_WPS)) & 0x10)
93                 cpu_relax();
94
95         __raw_writel(0x4444, base + OMAP_WATCHDOG_SPR);
96         while ((__raw_readl(base + OMAP_WATCHDOG_WPS)) & 0x10)
97                 cpu_relax();
98 }
99
100 static void omap_wdt_disable(struct omap_wdt_dev *wdev)
101 {
102         void __iomem *base = wdev->base;
103
104         /* sequence required to disable watchdog */
105         __raw_writel(0xAAAA, base + OMAP_WATCHDOG_SPR); /* TIMER_MODE */
106         while (__raw_readl(base + OMAP_WATCHDOG_WPS) & 0x10)
107                 cpu_relax();
108
109         __raw_writel(0x5555, base + OMAP_WATCHDOG_SPR); /* TIMER_MODE */
110         while (__raw_readl(base + OMAP_WATCHDOG_WPS) & 0x10)
111                 cpu_relax();
112 }
113
114 static void omap_wdt_adjust_timeout(unsigned new_timeout)
115 {
116         if (new_timeout < TIMER_MARGIN_MIN)
117                 new_timeout = TIMER_MARGIN_DEFAULT;
118         if (new_timeout > TIMER_MARGIN_MAX)
119                 new_timeout = TIMER_MARGIN_MAX;
120         timer_margin = new_timeout;
121 }
122
123 static void omap_wdt_set_timeout(struct omap_wdt_dev *wdev)
124 {
125         u32 pre_margin = GET_WLDR_VAL(timer_margin);
126         void __iomem *base = wdev->base;
127
128         /* just count up at 32 KHz */
129         while (__raw_readl(base + OMAP_WATCHDOG_WPS) & 0x04)
130                 cpu_relax();
131
132         __raw_writel(pre_margin, base + OMAP_WATCHDOG_LDR);
133         while (__raw_readl(base + OMAP_WATCHDOG_WPS) & 0x04)
134                 cpu_relax();
135 }
136
137 /*
138  *      Allow only one task to hold it open
139  */
140 static int omap_wdt_open(struct inode *inode, struct file *file)
141 {
142         struct omap_wdt_dev *wdev = platform_get_drvdata(omap_wdt_dev);
143         void __iomem *base = wdev->base;
144
145         if (test_and_set_bit(1, (unsigned long *)&(wdev->omap_wdt_users)))
146                 return -EBUSY;
147
148         clk_enable(wdev->ick);    /* Enable the interface clock */
149         clk_enable(wdev->fck);    /* Enable the functional clock */
150
151         /* initialize prescaler */
152         while (__raw_readl(base + OMAP_WATCHDOG_WPS) & 0x01)
153                 cpu_relax();
154
155         __raw_writel((1 << 5) | (PTV << 2), base + OMAP_WATCHDOG_CNTRL);
156         while (__raw_readl(base + OMAP_WATCHDOG_WPS) & 0x01)
157                 cpu_relax();
158
159         file->private_data = (void *) wdev;
160
161         omap_wdt_set_timeout(wdev);
162         omap_wdt_enable(wdev);
163
164         return nonseekable_open(inode, file);
165 }
166
167 static int omap_wdt_release(struct inode *inode, struct file *file)
168 {
169         struct omap_wdt_dev *wdev = file->private_data;
170
171         /*
172          *      Shut off the timer unless NOWAYOUT is defined.
173          */
174 #ifndef CONFIG_WATCHDOG_NOWAYOUT
175
176         omap_wdt_disable(wdev);
177
178         clk_disable(wdev->ick);
179         clk_disable(wdev->fck);
180 #else
181         printk(KERN_CRIT "omap_wdt: Unexpected close, not stopping!\n");
182 #endif
183         wdev->omap_wdt_users = 0;
184
185         return 0;
186 }
187
188 static ssize_t omap_wdt_write(struct file *file, const char __user *data,
189                 size_t len, loff_t *ppos)
190 {
191         struct omap_wdt_dev *wdev = file->private_data;
192
193         /* Refresh LOAD_TIME. */
194         if (len) {
195                 spin_lock(&wdt_lock);
196                 omap_wdt_ping(wdev);
197                 spin_unlock(&wdt_lock);
198         }
199         return len;
200 }
201
202 static long omap_wdt_ioctl(struct file *file, unsigned int cmd,
203                                                 unsigned long arg)
204 {
205         struct omap_wdt_dev *wdev;
206         int new_margin;
207         static const struct watchdog_info ident = {
208                 .identity = "OMAP Watchdog",
209                 .options = WDIOF_SETTIMEOUT,
210                 .firmware_version = 0,
211         };
212
213         wdev = file->private_data;
214
215         switch (cmd) {
216         case WDIOC_GETSUPPORT:
217                 return copy_to_user((struct watchdog_info __user *)arg, &ident,
218                                 sizeof(ident));
219         case WDIOC_GETSTATUS:
220                 return put_user(0, (int __user *)arg);
221         case WDIOC_GETBOOTSTATUS:
222                 if (cpu_is_omap16xx())
223                         return put_user(__raw_readw(ARM_SYSST),
224                                         (int __user *)arg);
225                 if (cpu_is_omap24xx())
226                         return put_user(omap_prcm_get_reset_sources(),
227                                         (int __user *)arg);
228         case WDIOC_KEEPALIVE:
229                 spin_lock(&wdt_lock);
230                 omap_wdt_ping(wdev);
231                 spin_unlock(&wdt_lock);
232                 return 0;
233         case WDIOC_SETTIMEOUT:
234                 if (get_user(new_margin, (int __user *)arg))
235                         return -EFAULT;
236                 omap_wdt_adjust_timeout(new_margin);
237
238                 spin_lock(&wdt_lock);
239                 omap_wdt_disable(wdev);
240                 omap_wdt_set_timeout(wdev);
241                 omap_wdt_enable(wdev);
242
243                 omap_wdt_ping(wdev);
244                 spin_unlock(&wdt_lock);
245                 /* Fall */
246         case WDIOC_GETTIMEOUT:
247                 return put_user(timer_margin, (int __user *)arg);
248         default:
249                 return -ENOTTY;
250         }
251 }
252
253 static const struct file_operations omap_wdt_fops = {
254         .owner = THIS_MODULE,
255         .write = omap_wdt_write,
256         .unlocked_ioctl = omap_wdt_ioctl,
257         .open = omap_wdt_open,
258         .release = omap_wdt_release,
259 };
260
261 static int __devinit omap_wdt_probe(struct platform_device *pdev)
262 {
263         struct resource *res, *mem;
264         struct omap_wdt_dev *wdev;
265         int ret;
266
267         /* reserve static register mappings */
268         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
269         if (!res) {
270                 ret = -ENOENT;
271                 goto err_get_resource;
272         }
273
274         if (omap_wdt_dev) {
275                 ret = -EBUSY;
276                 goto err_busy;
277         }
278
279         mem = request_mem_region(res->start, res->end - res->start + 1,
280                                  pdev->name);
281         if (!mem) {
282                 ret = -EBUSY;
283                 goto err_busy;
284         }
285
286         wdev = kzalloc(sizeof(struct omap_wdt_dev), GFP_KERNEL);
287         if (!wdev) {
288                 ret = -ENOMEM;
289                 goto err_kzalloc;
290         }
291
292         wdev->omap_wdt_users = 0;
293         wdev->mem = mem;
294
295         wdev->ick = clk_get(&pdev->dev, "ick");
296         if (IS_ERR(wdev->ick)) {
297                 ret = PTR_ERR(wdev->ick);
298                 wdev->ick = NULL;
299                 goto err_clk;
300         }
301         wdev->fck = clk_get(&pdev->dev, "fck");
302         if (IS_ERR(wdev->fck)) {
303                 ret = PTR_ERR(wdev->fck);
304                 wdev->fck = NULL;
305                 goto err_clk;
306         }
307
308         wdev->base = ioremap(res->start, res->end - res->start + 1);
309         if (!wdev->base) {
310                 ret = -ENOMEM;
311                 goto err_ioremap;
312         }
313
314         platform_set_drvdata(pdev, wdev);
315
316         omap_wdt_disable(wdev);
317         omap_wdt_adjust_timeout(timer_margin);
318
319         wdev->omap_wdt_miscdev.parent = &pdev->dev;
320         wdev->omap_wdt_miscdev.minor = WATCHDOG_MINOR;
321         wdev->omap_wdt_miscdev.name = "watchdog";
322         wdev->omap_wdt_miscdev.fops = &omap_wdt_fops;
323
324         ret = misc_register(&(wdev->omap_wdt_miscdev));
325         if (ret)
326                 goto err_misc;
327
328         pr_info("OMAP Watchdog Timer Rev 0x%02x: initial timeout %d sec\n",
329                 __raw_readl(wdev->base + OMAP_WATCHDOG_REV) & 0xFF,
330                 timer_margin);
331
332         /* autogate OCP interface clock */
333         __raw_writel(0x01, wdev->base + OMAP_WATCHDOG_SYS_CONFIG);
334
335         omap_wdt_dev = pdev;
336
337         return 0;
338
339 err_misc:
340         platform_set_drvdata(pdev, NULL);
341         iounmap(wdev->base);
342
343 err_ioremap:
344         wdev->base = NULL;
345
346 err_clk:
347         if (wdev->ick)
348                 clk_put(wdev->ick);
349         if (wdev->fck)
350                 clk_put(wdev->fck);
351         kfree(wdev);
352
353 err_kzalloc:
354         release_mem_region(res->start, res->end - res->start + 1);
355
356 err_busy:
357 err_get_resource:
358
359         return ret;
360 }
361
362 static void omap_wdt_shutdown(struct platform_device *pdev)
363 {
364         struct omap_wdt_dev *wdev = platform_get_drvdata(pdev);
365
366         if (wdev->omap_wdt_users)
367                 omap_wdt_disable(wdev);
368 }
369
370 static int __devexit omap_wdt_remove(struct platform_device *pdev)
371 {
372         struct omap_wdt_dev *wdev = platform_get_drvdata(pdev);
373         struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
374
375         if (!res)
376                 return -ENOENT;
377
378         misc_deregister(&(wdev->omap_wdt_miscdev));
379         release_mem_region(res->start, res->end - res->start + 1);
380         platform_set_drvdata(pdev, NULL);
381
382         clk_put(wdev->ick);
383         clk_put(wdev->fck);
384         iounmap(wdev->base);
385
386         kfree(wdev);
387         omap_wdt_dev = NULL;
388
389         return 0;
390 }
391
392 #ifdef  CONFIG_PM
393
394 /* REVISIT ... not clear this is the best way to handle system suspend; and
395  * it's very inappropriate for selective device suspend (e.g. suspending this
396  * through sysfs rather than by stopping the watchdog daemon).  Also, this
397  * may not play well enough with NOWAYOUT...
398  */
399
400 static int omap_wdt_suspend(struct platform_device *pdev, pm_message_t state)
401 {
402         struct omap_wdt_dev *wdev = platform_get_drvdata(pdev);
403
404         if (wdev->omap_wdt_users)
405                 omap_wdt_disable(wdev);
406
407         return 0;
408 }
409
410 static int omap_wdt_resume(struct platform_device *pdev)
411 {
412         struct omap_wdt_dev *wdev = platform_get_drvdata(pdev);
413
414         if (wdev->omap_wdt_users) {
415                 omap_wdt_enable(wdev);
416                 omap_wdt_ping(wdev);
417         }
418
419         return 0;
420 }
421
422 #else
423 #define omap_wdt_suspend        NULL
424 #define omap_wdt_resume         NULL
425 #endif
426
427 static struct platform_driver omap_wdt_driver = {
428         .probe          = omap_wdt_probe,
429         .remove         = __devexit_p(omap_wdt_remove),
430         .shutdown       = omap_wdt_shutdown,
431         .suspend        = omap_wdt_suspend,
432         .resume         = omap_wdt_resume,
433         .driver         = {
434                 .owner  = THIS_MODULE,
435                 .name   = "omap_wdt",
436         },
437 };
438
439 static int __init omap_wdt_init(void)
440 {
441         spin_lock_init(&wdt_lock);
442         return platform_driver_register(&omap_wdt_driver);
443 }
444
445 static void __exit omap_wdt_exit(void)
446 {
447         platform_driver_unregister(&omap_wdt_driver);
448 }
449
450 module_init(omap_wdt_init);
451 module_exit(omap_wdt_exit);
452
453 MODULE_AUTHOR("George G. Davis");
454 MODULE_LICENSE("GPL");
455 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
456 MODULE_ALIAS("platform:omap_wdt");