4 * Watchdog driver for the TI OMAP 16xx & 24xx/34xx 32KHz (non-secure) watchdog
6 * Author: MontaVista Software, Inc.
7 * <gdavis@mvista.com> or <source@mvista.com>
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
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>
21 * Copyright (c) 2004 Texas Instruments.
22 * 1. Modified to support OMAP1610 32-KHz watchdog timer
23 * 2. Ported to 2.6 kernel
25 * Copyright (c) 2005 David Brownell
26 * Use the driver model and standard identifiers; handle bigger timeouts.
29 #include <linux/module.h>
30 #include <linux/types.h>
31 #include <linux/kernel.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/bitops.h>
43 #include <linux/uaccess.h>
44 #include <linux/slab.h>
45 #include <linux/pm_runtime.h>
46 #include <mach/hardware.h>
47 #include <plat/prcm.h>
51 static struct platform_device *omap_wdt_dev;
53 static unsigned timer_margin;
54 module_param(timer_margin, uint, 0);
55 MODULE_PARM_DESC(timer_margin, "initial watchdog timeout (in seconds)");
57 static unsigned int wdt_trgr_pattern = 0x1234;
58 static spinlock_t wdt_lock;
61 void __iomem *base; /* physical */
65 struct miscdevice omap_wdt_miscdev;
68 static void omap_wdt_ping(struct omap_wdt_dev *wdev)
70 void __iomem *base = wdev->base;
72 /* wait for posted write to complete */
73 while ((__raw_readl(base + OMAP_WATCHDOG_WPS)) & 0x08)
76 wdt_trgr_pattern = ~wdt_trgr_pattern;
77 __raw_writel(wdt_trgr_pattern, (base + OMAP_WATCHDOG_TGR));
79 /* wait for posted write to complete */
80 while ((__raw_readl(base + OMAP_WATCHDOG_WPS)) & 0x08)
82 /* reloaded WCRR from WLDR */
85 static void omap_wdt_enable(struct omap_wdt_dev *wdev)
87 void __iomem *base = wdev->base;
89 /* Sequence to enable the watchdog */
90 __raw_writel(0xBBBB, base + OMAP_WATCHDOG_SPR);
91 while ((__raw_readl(base + OMAP_WATCHDOG_WPS)) & 0x10)
94 __raw_writel(0x4444, base + OMAP_WATCHDOG_SPR);
95 while ((__raw_readl(base + OMAP_WATCHDOG_WPS)) & 0x10)
99 static void omap_wdt_disable(struct omap_wdt_dev *wdev)
101 void __iomem *base = wdev->base;
103 /* sequence required to disable watchdog */
104 __raw_writel(0xAAAA, base + OMAP_WATCHDOG_SPR); /* TIMER_MODE */
105 while (__raw_readl(base + OMAP_WATCHDOG_WPS) & 0x10)
108 __raw_writel(0x5555, base + OMAP_WATCHDOG_SPR); /* TIMER_MODE */
109 while (__raw_readl(base + OMAP_WATCHDOG_WPS) & 0x10)
113 static void omap_wdt_adjust_timeout(unsigned new_timeout)
115 if (new_timeout < TIMER_MARGIN_MIN)
116 new_timeout = TIMER_MARGIN_DEFAULT;
117 if (new_timeout > TIMER_MARGIN_MAX)
118 new_timeout = TIMER_MARGIN_MAX;
119 timer_margin = new_timeout;
122 static void omap_wdt_set_timeout(struct omap_wdt_dev *wdev)
124 u32 pre_margin = GET_WLDR_VAL(timer_margin);
125 void __iomem *base = wdev->base;
127 /* just count up at 32 KHz */
128 while (__raw_readl(base + OMAP_WATCHDOG_WPS) & 0x04)
131 __raw_writel(pre_margin, base + OMAP_WATCHDOG_LDR);
132 while (__raw_readl(base + OMAP_WATCHDOG_WPS) & 0x04)
137 * Allow only one task to hold it open
139 static int omap_wdt_open(struct inode *inode, struct file *file)
141 struct omap_wdt_dev *wdev = platform_get_drvdata(omap_wdt_dev);
142 void __iomem *base = wdev->base;
144 if (test_and_set_bit(1, (unsigned long *)&(wdev->omap_wdt_users)))
147 pm_runtime_get_sync(wdev->dev);
149 /* initialize prescaler */
150 while (__raw_readl(base + OMAP_WATCHDOG_WPS) & 0x01)
153 __raw_writel((1 << 5) | (PTV << 2), base + OMAP_WATCHDOG_CNTRL);
154 while (__raw_readl(base + OMAP_WATCHDOG_WPS) & 0x01)
157 file->private_data = (void *) wdev;
159 omap_wdt_set_timeout(wdev);
160 omap_wdt_ping(wdev); /* trigger loading of new timeout value */
161 omap_wdt_enable(wdev);
163 return nonseekable_open(inode, file);
166 static int omap_wdt_release(struct inode *inode, struct file *file)
168 struct omap_wdt_dev *wdev = file->private_data;
171 * Shut off the timer unless NOWAYOUT is defined.
173 #ifndef CONFIG_WATCHDOG_NOWAYOUT
175 omap_wdt_disable(wdev);
177 pm_runtime_put_sync(wdev->dev);
179 printk(KERN_CRIT "omap_wdt: Unexpected close, not stopping!\n");
181 wdev->omap_wdt_users = 0;
186 static ssize_t omap_wdt_write(struct file *file, const char __user *data,
187 size_t len, loff_t *ppos)
189 struct omap_wdt_dev *wdev = file->private_data;
191 /* Refresh LOAD_TIME. */
193 spin_lock(&wdt_lock);
195 spin_unlock(&wdt_lock);
200 static long omap_wdt_ioctl(struct file *file, unsigned int cmd,
203 struct omap_wdt_dev *wdev;
205 static const struct watchdog_info ident = {
206 .identity = "OMAP Watchdog",
207 .options = WDIOF_SETTIMEOUT,
208 .firmware_version = 0,
211 wdev = file->private_data;
214 case WDIOC_GETSUPPORT:
215 return copy_to_user((struct watchdog_info __user *)arg, &ident,
217 case WDIOC_GETSTATUS:
218 return put_user(0, (int __user *)arg);
219 case WDIOC_GETBOOTSTATUS:
220 if (cpu_is_omap16xx())
221 return put_user(__raw_readw(ARM_SYSST),
223 if (cpu_is_omap24xx())
224 return put_user(omap_prcm_get_reset_sources(),
226 case WDIOC_KEEPALIVE:
227 spin_lock(&wdt_lock);
229 spin_unlock(&wdt_lock);
231 case WDIOC_SETTIMEOUT:
232 if (get_user(new_margin, (int __user *)arg))
234 omap_wdt_adjust_timeout(new_margin);
236 spin_lock(&wdt_lock);
237 omap_wdt_disable(wdev);
238 omap_wdt_set_timeout(wdev);
239 omap_wdt_enable(wdev);
242 spin_unlock(&wdt_lock);
244 case WDIOC_GETTIMEOUT:
245 return put_user(timer_margin, (int __user *)arg);
251 static const struct file_operations omap_wdt_fops = {
252 .owner = THIS_MODULE,
253 .write = omap_wdt_write,
254 .unlocked_ioctl = omap_wdt_ioctl,
255 .open = omap_wdt_open,
256 .release = omap_wdt_release,
259 static int __devinit omap_wdt_probe(struct platform_device *pdev)
261 struct resource *res, *mem;
262 struct omap_wdt_dev *wdev;
265 /* reserve static register mappings */
266 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
269 goto err_get_resource;
277 mem = request_mem_region(res->start, resource_size(res), pdev->name);
283 wdev = kzalloc(sizeof(struct omap_wdt_dev), GFP_KERNEL);
289 wdev->omap_wdt_users = 0;
291 wdev->dev = &pdev->dev;
293 wdev->base = ioremap(res->start, resource_size(res));
299 platform_set_drvdata(pdev, wdev);
301 pm_runtime_enable(wdev->dev);
302 pm_runtime_get_sync(wdev->dev);
304 omap_wdt_disable(wdev);
305 omap_wdt_adjust_timeout(timer_margin);
307 wdev->omap_wdt_miscdev.parent = &pdev->dev;
308 wdev->omap_wdt_miscdev.minor = WATCHDOG_MINOR;
309 wdev->omap_wdt_miscdev.name = "watchdog";
310 wdev->omap_wdt_miscdev.fops = &omap_wdt_fops;
312 ret = misc_register(&(wdev->omap_wdt_miscdev));
316 pr_info("OMAP Watchdog Timer Rev 0x%02x: initial timeout %d sec\n",
317 __raw_readl(wdev->base + OMAP_WATCHDOG_REV) & 0xFF,
320 pm_runtime_put_sync(wdev->dev);
327 platform_set_drvdata(pdev, NULL);
335 release_mem_region(res->start, resource_size(res));
343 static void omap_wdt_shutdown(struct platform_device *pdev)
345 struct omap_wdt_dev *wdev = platform_get_drvdata(pdev);
347 if (wdev->omap_wdt_users)
348 omap_wdt_disable(wdev);
351 static int __devexit omap_wdt_remove(struct platform_device *pdev)
353 struct omap_wdt_dev *wdev = platform_get_drvdata(pdev);
354 struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
359 misc_deregister(&(wdev->omap_wdt_miscdev));
360 release_mem_region(res->start, resource_size(res));
361 platform_set_drvdata(pdev, NULL);
373 /* REVISIT ... not clear this is the best way to handle system suspend; and
374 * it's very inappropriate for selective device suspend (e.g. suspending this
375 * through sysfs rather than by stopping the watchdog daemon). Also, this
376 * may not play well enough with NOWAYOUT...
379 static int omap_wdt_suspend(struct platform_device *pdev, pm_message_t state)
381 struct omap_wdt_dev *wdev = platform_get_drvdata(pdev);
383 if (wdev->omap_wdt_users)
384 omap_wdt_disable(wdev);
389 static int omap_wdt_resume(struct platform_device *pdev)
391 struct omap_wdt_dev *wdev = platform_get_drvdata(pdev);
393 if (wdev->omap_wdt_users) {
394 omap_wdt_enable(wdev);
402 #define omap_wdt_suspend NULL
403 #define omap_wdt_resume NULL
406 static struct platform_driver omap_wdt_driver = {
407 .probe = omap_wdt_probe,
408 .remove = __devexit_p(omap_wdt_remove),
409 .shutdown = omap_wdt_shutdown,
410 .suspend = omap_wdt_suspend,
411 .resume = omap_wdt_resume,
413 .owner = THIS_MODULE,
418 static int __init omap_wdt_init(void)
420 spin_lock_init(&wdt_lock);
421 return platform_driver_register(&omap_wdt_driver);
424 static void __exit omap_wdt_exit(void)
426 platform_driver_unregister(&omap_wdt_driver);
429 module_init(omap_wdt_init);
430 module_exit(omap_wdt_exit);
432 MODULE_AUTHOR("George G. Davis");
433 MODULE_LICENSE("GPL");
434 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
435 MODULE_ALIAS("platform:omap_wdt");