PCI: make no_pci_devices() use the pci_bus_type list
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / drivers / watchdog / s3c2410_wdt.c
blob98532c0e0689c93726976cb3507385321849f828
1 /* linux/drivers/char/watchdog/s3c2410_wdt.c
3 * Copyright (c) 2004 Simtec Electronics
4 * Ben Dooks <ben@simtec.co.uk>
6 * S3C2410 Watchdog Timer Support
8 * Based on, softdog.c by Alan Cox,
9 * (c) Copyright 1996 Alan Cox <alan@redhat.com>
11 * This program is free software; you can redistribute it and/or modify
12 * it under the terms of the GNU General Public License as published by
13 * the Free Software Foundation; either version 2 of the License, or
14 * (at your option) any later version.
16 * This program is distributed in the hope that it will be useful,
17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19 * GNU General Public License for more details.
21 * You should have received a copy of the GNU General Public License
22 * along with this program; if not, write to the Free Software
23 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
25 * Changelog:
26 * 05-Oct-2004 BJD Added semaphore init to stop crashes on open
27 * Fixed tmr_count / wdt_count confusion
28 * Added configurable debug
30 * 11-Jan-2005 BJD Fixed divide-by-2 in timeout code
32 * 25-Jan-2005 DA Added suspend/resume support
33 * Replaced reboot notifier with .shutdown method
35 * 10-Mar-2005 LCVR Changed S3C2410_VA to S3C24XX_VA
38 #include <linux/module.h>
39 #include <linux/moduleparam.h>
40 #include <linux/types.h>
41 #include <linux/timer.h>
42 #include <linux/miscdevice.h>
43 #include <linux/watchdog.h>
44 #include <linux/fs.h>
45 #include <linux/init.h>
46 #include <linux/platform_device.h>
47 #include <linux/interrupt.h>
48 #include <linux/clk.h>
50 #include <asm/uaccess.h>
51 #include <asm/io.h>
53 #include <asm/arch/map.h>
55 #undef S3C_VA_WATCHDOG
56 #define S3C_VA_WATCHDOG (0)
58 #include <asm/plat-s3c/regs-watchdog.h>
60 #define PFX "s3c2410-wdt: "
62 #define CONFIG_S3C2410_WATCHDOG_ATBOOT (0)
63 #define CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME (15)
65 static int nowayout = WATCHDOG_NOWAYOUT;
66 static int tmr_margin = CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME;
67 static int tmr_atboot = CONFIG_S3C2410_WATCHDOG_ATBOOT;
68 static int soft_noboot = 0;
69 static int debug = 0;
71 module_param(tmr_margin, int, 0);
72 module_param(tmr_atboot, int, 0);
73 module_param(nowayout, int, 0);
74 module_param(soft_noboot, int, 0);
75 module_param(debug, int, 0);
77 MODULE_PARM_DESC(tmr_margin, "Watchdog tmr_margin in seconds. default=" __MODULE_STRING(CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME) ")");
79 MODULE_PARM_DESC(tmr_atboot, "Watchdog is started at boot time if set to 1, default=" __MODULE_STRING(CONFIG_S3C2410_WATCHDOG_ATBOOT));
81 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
83 MODULE_PARM_DESC(soft_noboot, "Watchdog action, set to 1 to ignore reboots, 0 to reboot (default depends on ONLY_TESTING)");
85 MODULE_PARM_DESC(debug, "Watchdog debug, set to >1 for debug, (default 0)");
88 typedef enum close_state {
89 CLOSE_STATE_NOT,
90 CLOSE_STATE_ALLOW=0x4021
91 } close_state_t;
93 static DECLARE_MUTEX(open_lock);
95 static struct device *wdt_dev; /* platform device attached to */
96 static struct resource *wdt_mem;
97 static struct resource *wdt_irq;
98 static struct clk *wdt_clock;
99 static void __iomem *wdt_base;
100 static unsigned int wdt_count;
101 static close_state_t allow_close;
103 /* watchdog control routines */
105 #define DBG(msg...) do { \
106 if (debug) \
107 printk(KERN_INFO msg); \
108 } while(0)
110 /* functions */
112 static int s3c2410wdt_keepalive(void)
114 writel(wdt_count, wdt_base + S3C2410_WTCNT);
115 return 0;
118 static int s3c2410wdt_stop(void)
120 unsigned long wtcon;
122 wtcon = readl(wdt_base + S3C2410_WTCON);
123 wtcon &= ~(S3C2410_WTCON_ENABLE | S3C2410_WTCON_RSTEN);
124 writel(wtcon, wdt_base + S3C2410_WTCON);
126 return 0;
129 static int s3c2410wdt_start(void)
131 unsigned long wtcon;
133 s3c2410wdt_stop();
135 wtcon = readl(wdt_base + S3C2410_WTCON);
136 wtcon |= S3C2410_WTCON_ENABLE | S3C2410_WTCON_DIV128;
138 if (soft_noboot) {
139 wtcon |= S3C2410_WTCON_INTEN;
140 wtcon &= ~S3C2410_WTCON_RSTEN;
141 } else {
142 wtcon &= ~S3C2410_WTCON_INTEN;
143 wtcon |= S3C2410_WTCON_RSTEN;
146 DBG("%s: wdt_count=0x%08x, wtcon=%08lx\n",
147 __func__, wdt_count, wtcon);
149 writel(wdt_count, wdt_base + S3C2410_WTDAT);
150 writel(wdt_count, wdt_base + S3C2410_WTCNT);
151 writel(wtcon, wdt_base + S3C2410_WTCON);
153 return 0;
156 static int s3c2410wdt_set_heartbeat(int timeout)
158 unsigned int freq = clk_get_rate(wdt_clock);
159 unsigned int count;
160 unsigned int divisor = 1;
161 unsigned long wtcon;
163 if (timeout < 1)
164 return -EINVAL;
166 freq /= 128;
167 count = timeout * freq;
169 DBG("%s: count=%d, timeout=%d, freq=%d\n",
170 __func__, count, timeout, freq);
172 /* if the count is bigger than the watchdog register,
173 then work out what we need to do (and if) we can
174 actually make this value
177 if (count >= 0x10000) {
178 for (divisor = 1; divisor <= 0x100; divisor++) {
179 if ((count / divisor) < 0x10000)
180 break;
183 if ((count / divisor) >= 0x10000) {
184 dev_err(wdt_dev, "timeout %d too big\n", timeout);
185 return -EINVAL;
189 tmr_margin = timeout;
191 DBG("%s: timeout=%d, divisor=%d, count=%d (%08x)\n",
192 __func__, timeout, divisor, count, count/divisor);
194 count /= divisor;
195 wdt_count = count;
197 /* update the pre-scaler */
198 wtcon = readl(wdt_base + S3C2410_WTCON);
199 wtcon &= ~S3C2410_WTCON_PRESCALE_MASK;
200 wtcon |= S3C2410_WTCON_PRESCALE(divisor-1);
202 writel(count, wdt_base + S3C2410_WTDAT);
203 writel(wtcon, wdt_base + S3C2410_WTCON);
205 return 0;
209 * /dev/watchdog handling
212 static int s3c2410wdt_open(struct inode *inode, struct file *file)
214 if(down_trylock(&open_lock))
215 return -EBUSY;
217 if (nowayout)
218 __module_get(THIS_MODULE);
220 allow_close = CLOSE_STATE_NOT;
222 /* start the timer */
223 s3c2410wdt_start();
224 return nonseekable_open(inode, file);
227 static int s3c2410wdt_release(struct inode *inode, struct file *file)
230 * Shut off the timer.
231 * Lock it in if it's a module and we set nowayout
234 if (allow_close == CLOSE_STATE_ALLOW) {
235 s3c2410wdt_stop();
236 } else {
237 dev_err(wdt_dev, "Unexpected close, not stopping watchdog\n");
238 s3c2410wdt_keepalive();
241 allow_close = CLOSE_STATE_NOT;
242 up(&open_lock);
243 return 0;
246 static ssize_t s3c2410wdt_write(struct file *file, const char __user *data,
247 size_t len, loff_t *ppos)
250 * Refresh the timer.
252 if(len) {
253 if (!nowayout) {
254 size_t i;
256 /* In case it was set long ago */
257 allow_close = CLOSE_STATE_NOT;
259 for (i = 0; i != len; i++) {
260 char c;
262 if (get_user(c, data + i))
263 return -EFAULT;
264 if (c == 'V')
265 allow_close = CLOSE_STATE_ALLOW;
269 s3c2410wdt_keepalive();
271 return len;
274 #define OPTIONS WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE
276 static struct watchdog_info s3c2410_wdt_ident = {
277 .options = OPTIONS,
278 .firmware_version = 0,
279 .identity = "S3C2410 Watchdog",
283 static int s3c2410wdt_ioctl(struct inode *inode, struct file *file,
284 unsigned int cmd, unsigned long arg)
286 void __user *argp = (void __user *)arg;
287 int __user *p = argp;
288 int new_margin;
290 switch (cmd) {
291 default:
292 return -ENOTTY;
294 case WDIOC_GETSUPPORT:
295 return copy_to_user(argp, &s3c2410_wdt_ident,
296 sizeof(s3c2410_wdt_ident)) ? -EFAULT : 0;
298 case WDIOC_GETSTATUS:
299 case WDIOC_GETBOOTSTATUS:
300 return put_user(0, p);
302 case WDIOC_KEEPALIVE:
303 s3c2410wdt_keepalive();
304 return 0;
306 case WDIOC_SETTIMEOUT:
307 if (get_user(new_margin, p))
308 return -EFAULT;
310 if (s3c2410wdt_set_heartbeat(new_margin))
311 return -EINVAL;
313 s3c2410wdt_keepalive();
314 return put_user(tmr_margin, p);
316 case WDIOC_GETTIMEOUT:
317 return put_user(tmr_margin, p);
321 /* kernel interface */
323 static const struct file_operations s3c2410wdt_fops = {
324 .owner = THIS_MODULE,
325 .llseek = no_llseek,
326 .write = s3c2410wdt_write,
327 .ioctl = s3c2410wdt_ioctl,
328 .open = s3c2410wdt_open,
329 .release = s3c2410wdt_release,
332 static struct miscdevice s3c2410wdt_miscdev = {
333 .minor = WATCHDOG_MINOR,
334 .name = "watchdog",
335 .fops = &s3c2410wdt_fops,
338 /* interrupt handler code */
340 static irqreturn_t s3c2410wdt_irq(int irqno, void *param)
342 dev_info(wdt_dev, "watchdog timer expired (irq)\n");
344 s3c2410wdt_keepalive();
345 return IRQ_HANDLED;
347 /* device interface */
349 static int s3c2410wdt_probe(struct platform_device *pdev)
351 struct resource *res;
352 struct device *dev;
353 unsigned int wtcon;
354 int started = 0;
355 int ret;
356 int size;
358 DBG("%s: probe=%p\n", __func__, pdev);
360 dev = &pdev->dev;
361 wdt_dev = &pdev->dev;
363 /* get the memory region for the watchdog timer */
365 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
366 if (res == NULL) {
367 dev_err(dev, "no memory resource specified\n");
368 return -ENOENT;
371 size = (res->end-res->start)+1;
372 wdt_mem = request_mem_region(res->start, size, pdev->name);
373 if (wdt_mem == NULL) {
374 dev_err(dev, "failed to get memory region\n");
375 ret = -ENOENT;
376 goto err_req;
379 wdt_base = ioremap(res->start, size);
380 if (wdt_base == 0) {
381 dev_err(dev, "failed to ioremap() region\n");
382 ret = -EINVAL;
383 goto err_req;
386 DBG("probe: mapped wdt_base=%p\n", wdt_base);
388 wdt_irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
389 if (wdt_irq == NULL) {
390 dev_err(dev, "no irq resource specified\n");
391 ret = -ENOENT;
392 goto err_map;
395 ret = request_irq(wdt_irq->start, s3c2410wdt_irq, 0, pdev->name, pdev);
396 if (ret != 0) {
397 dev_err(dev, "failed to install irq (%d)\n", ret);
398 goto err_map;
401 wdt_clock = clk_get(&pdev->dev, "watchdog");
402 if (IS_ERR(wdt_clock)) {
403 dev_err(dev, "failed to find watchdog clock source\n");
404 ret = PTR_ERR(wdt_clock);
405 goto err_irq;
408 clk_enable(wdt_clock);
410 /* see if we can actually set the requested timer margin, and if
411 * not, try the default value */
413 if (s3c2410wdt_set_heartbeat(tmr_margin)) {
414 started = s3c2410wdt_set_heartbeat(CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME);
416 if (started == 0) {
417 dev_info(dev,"tmr_margin value out of range, default %d used\n",
418 CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME);
419 } else {
420 dev_info(dev, "default timer value is out of range, cannot start\n");
424 ret = misc_register(&s3c2410wdt_miscdev);
425 if (ret) {
426 dev_err(dev, "cannot register miscdev on minor=%d (%d)\n",
427 WATCHDOG_MINOR, ret);
428 goto err_clk;
431 if (tmr_atboot && started == 0) {
432 dev_info(dev, "starting watchdog timer\n");
433 s3c2410wdt_start();
434 } else if (!tmr_atboot) {
435 /* if we're not enabling the watchdog, then ensure it is
436 * disabled if it has been left running from the bootloader
437 * or other source */
439 s3c2410wdt_stop();
442 /* print out a statement of readiness */
444 wtcon = readl(wdt_base + S3C2410_WTCON);
446 dev_info(dev, "watchdog %sactive, reset %sabled, irq %sabled\n",
447 (wtcon & S3C2410_WTCON_ENABLE) ? "" : "in",
448 (wtcon & S3C2410_WTCON_RSTEN) ? "" : "dis",
449 (wtcon & S3C2410_WTCON_INTEN) ? "" : "en");
451 return 0;
453 err_clk:
454 clk_disable(wdt_clock);
455 clk_put(wdt_clock);
457 err_irq:
458 free_irq(wdt_irq->start, pdev);
460 err_map:
461 iounmap(wdt_base);
463 err_req:
464 release_resource(wdt_mem);
465 kfree(wdt_mem);
467 return ret;
470 static int s3c2410wdt_remove(struct platform_device *dev)
472 release_resource(wdt_mem);
473 kfree(wdt_mem);
474 wdt_mem = NULL;
476 free_irq(wdt_irq->start, dev);
477 wdt_irq = NULL;
479 clk_disable(wdt_clock);
480 clk_put(wdt_clock);
481 wdt_clock = NULL;
483 iounmap(wdt_base);
484 misc_deregister(&s3c2410wdt_miscdev);
485 return 0;
488 static void s3c2410wdt_shutdown(struct platform_device *dev)
490 s3c2410wdt_stop();
493 #ifdef CONFIG_PM
495 static unsigned long wtcon_save;
496 static unsigned long wtdat_save;
498 static int s3c2410wdt_suspend(struct platform_device *dev, pm_message_t state)
500 /* Save watchdog state, and turn it off. */
501 wtcon_save = readl(wdt_base + S3C2410_WTCON);
502 wtdat_save = readl(wdt_base + S3C2410_WTDAT);
504 /* Note that WTCNT doesn't need to be saved. */
505 s3c2410wdt_stop();
507 return 0;
510 static int s3c2410wdt_resume(struct platform_device *dev)
512 /* Restore watchdog state. */
514 writel(wtdat_save, wdt_base + S3C2410_WTDAT);
515 writel(wtdat_save, wdt_base + S3C2410_WTCNT); /* Reset count */
516 writel(wtcon_save, wdt_base + S3C2410_WTCON);
518 printk(KERN_INFO PFX "watchdog %sabled\n",
519 (wtcon_save & S3C2410_WTCON_ENABLE) ? "en" : "dis");
521 return 0;
524 #else
525 #define s3c2410wdt_suspend NULL
526 #define s3c2410wdt_resume NULL
527 #endif /* CONFIG_PM */
530 static struct platform_driver s3c2410wdt_driver = {
531 .probe = s3c2410wdt_probe,
532 .remove = s3c2410wdt_remove,
533 .shutdown = s3c2410wdt_shutdown,
534 .suspend = s3c2410wdt_suspend,
535 .resume = s3c2410wdt_resume,
536 .driver = {
537 .owner = THIS_MODULE,
538 .name = "s3c2410-wdt",
543 static char banner[] __initdata = KERN_INFO "S3C2410 Watchdog Timer, (c) 2004 Simtec Electronics\n";
545 static int __init watchdog_init(void)
547 printk(banner);
548 return platform_driver_register(&s3c2410wdt_driver);
551 static void __exit watchdog_exit(void)
553 platform_driver_unregister(&s3c2410wdt_driver);
556 module_init(watchdog_init);
557 module_exit(watchdog_exit);
559 MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>, "
560 "Dimitry Andric <dimitry.andric@tomtom.com>");
561 MODULE_DESCRIPTION("S3C2410 Watchdog Device Driver");
562 MODULE_LICENSE("GPL");
563 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
564 MODULE_ALIAS("platform:s3c2410-wdt");