2 * linux/drivers/char/watchdog/omap_wdt.c
4 * Watchdog driver for the TI OMAP 16xx & 24xx 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@redhat.com>
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/clk.h>
42 #include <linux/bitops.h>
44 #include <linux/uaccess.h>
45 #include <linux/hardware.h>
47 #include <asm/arch/prcm.h>
51 static unsigned timer_margin;
52 module_param(timer_margin, uint, 0);
53 MODULE_PARM_DESC(timer_margin, "initial watchdog timeout (in seconds)");
55 static int omap_wdt_users;
56 static struct clk *armwdt_ck;
57 static struct clk *mpu_wdt_ick;
58 static struct clk *mpu_wdt_fck;
60 static unsigned int wdt_trgr_pattern = 0x1234;
61 static spinlock_t wdt_lock;
63 static void omap_wdt_ping(void)
65 /* wait for posted write to complete */
66 while ((omap_readl(OMAP_WATCHDOG_WPS)) & 0x08)
68 wdt_trgr_pattern = ~wdt_trgr_pattern;
69 omap_writel(wdt_trgr_pattern, (OMAP_WATCHDOG_TGR));
70 /* wait for posted write to complete */
71 while ((omap_readl(OMAP_WATCHDOG_WPS)) & 0x08)
73 /* reloaded WCRR from WLDR */
76 static void omap_wdt_enable(void)
78 /* Sequence to enable the watchdog */
79 omap_writel(0xBBBB, OMAP_WATCHDOG_SPR);
80 while ((omap_readl(OMAP_WATCHDOG_WPS)) & 0x10)
82 omap_writel(0x4444, OMAP_WATCHDOG_SPR);
83 while ((omap_readl(OMAP_WATCHDOG_WPS)) & 0x10)
87 static void omap_wdt_disable(void)
89 /* sequence required to disable watchdog */
90 omap_writel(0xAAAA, OMAP_WATCHDOG_SPR); /* TIMER_MODE */
91 while (omap_readl(OMAP_WATCHDOG_WPS) & 0x10)
93 omap_writel(0x5555, OMAP_WATCHDOG_SPR); /* TIMER_MODE */
94 while (omap_readl(OMAP_WATCHDOG_WPS) & 0x10)
98 static void omap_wdt_adjust_timeout(unsigned new_timeout)
100 if (new_timeout < TIMER_MARGIN_MIN)
101 new_timeout = TIMER_MARGIN_DEFAULT;
102 if (new_timeout > TIMER_MARGIN_MAX)
103 new_timeout = TIMER_MARGIN_MAX;
104 timer_margin = new_timeout;
107 static void omap_wdt_set_timeout(void)
109 u32 pre_margin = GET_WLDR_VAL(timer_margin);
111 /* just count up at 32 KHz */
112 while (omap_readl(OMAP_WATCHDOG_WPS) & 0x04)
114 omap_writel(pre_margin, OMAP_WATCHDOG_LDR);
115 while (omap_readl(OMAP_WATCHDOG_WPS) & 0x04)
120 * Allow only one task to hold it open
123 static int omap_wdt_open(struct inode *inode, struct file *file)
125 if (test_and_set_bit(1, (unsigned long *)&omap_wdt_users))
128 if (cpu_is_omap16xx())
129 clk_enable(armwdt_ck); /* Enable the clock */
131 if (cpu_is_omap24xx()) {
132 clk_enable(mpu_wdt_ick); /* Enable the interface clock */
133 clk_enable(mpu_wdt_fck); /* Enable the functional clock */
136 /* initialize prescaler */
137 while (omap_readl(OMAP_WATCHDOG_WPS) & 0x01)
139 omap_writel((1 << 5) | (PTV << 2), OMAP_WATCHDOG_CNTRL);
140 while (omap_readl(OMAP_WATCHDOG_WPS) & 0x01)
143 omap_wdt_set_timeout();
145 return nonseekable_open(inode, file);
148 static int omap_wdt_release(struct inode *inode, struct file *file)
151 * Shut off the timer unless NOWAYOUT is defined.
153 #ifndef CONFIG_WATCHDOG_NOWAYOUT
156 if (cpu_is_omap16xx()) {
157 clk_disable(armwdt_ck); /* Disable the clock */
162 if (cpu_is_omap24xx()) {
163 clk_disable(mpu_wdt_ick); /* Disable the clock */
164 clk_disable(mpu_wdt_fck); /* Disable the clock */
165 clk_put(mpu_wdt_ick);
166 clk_put(mpu_wdt_fck);
171 printk(KERN_CRIT "omap_wdt: Unexpected close, not stopping!\n");
177 static ssize_t omap_wdt_write(struct file *file, const char __user *data,
178 size_t len, loff_t *ppos)
180 /* Refresh LOAD_TIME. */
182 spin_lock(&wdt_lock);
184 spin_unlock(&wdt_lock);
189 static long omap_wdt_ioctl(struct file *file, unsigned int cmd,
193 static const struct watchdog_info ident = {
194 .identity = "OMAP Watchdog",
195 .options = WDIOF_SETTIMEOUT,
196 .firmware_version = 0,
202 case WDIOC_GETSUPPORT:
203 return copy_to_user((struct watchdog_info __user *)arg, &ident,
205 case WDIOC_GETSTATUS:
206 return put_user(0, (int __user *)arg);
207 case WDIOC_GETBOOTSTATUS:
208 if (cpu_is_omap16xx())
209 return put_user(omap_readw(ARM_SYSST),
211 if (cpu_is_omap24xx())
212 return put_user(omap_prcm_get_reset_sources(),
214 case WDIOC_KEEPALIVE:
215 spin_lock(&wdt_lock);
217 spin_unlock(&wdt_lock);
219 case WDIOC_SETTIMEOUT:
220 if (get_user(new_margin, (int __user *)arg))
222 omap_wdt_adjust_timeout(new_margin);
224 spin_lock(&wdt_lock);
226 omap_wdt_set_timeout();
230 spin_unlock(&wdt_lock);
232 case WDIOC_GETTIMEOUT:
233 return put_user(timer_margin, (int __user *)arg);
237 static const struct file_operations omap_wdt_fops = {
238 .owner = THIS_MODULE,
239 .write = omap_wdt_write,
240 .unlocked_ioctl = omap_wdt_ioctl,
241 .open = omap_wdt_open,
242 .release = omap_wdt_release,
245 static struct miscdevice omap_wdt_miscdev = {
246 .minor = WATCHDOG_MINOR,
248 .fops = &omap_wdt_fops
251 static int __init omap_wdt_probe(struct platform_device *pdev)
253 struct resource *res, *mem;
256 /* reserve static register mappings */
257 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
261 mem = request_mem_region(res->start, res->end - res->start + 1,
266 platform_set_drvdata(pdev, mem);
270 if (cpu_is_omap16xx()) {
271 armwdt_ck = clk_get(&pdev->dev, "armwdt_ck");
272 if (IS_ERR(armwdt_ck)) {
273 ret = PTR_ERR(armwdt_ck);
279 if (cpu_is_omap24xx()) {
280 mpu_wdt_ick = clk_get(&pdev->dev, "mpu_wdt_ick");
281 if (IS_ERR(mpu_wdt_ick)) {
282 ret = PTR_ERR(mpu_wdt_ick);
286 mpu_wdt_fck = clk_get(&pdev->dev, "mpu_wdt_fck");
287 if (IS_ERR(mpu_wdt_fck)) {
288 ret = PTR_ERR(mpu_wdt_fck);
295 omap_wdt_adjust_timeout(timer_margin);
297 omap_wdt_miscdev.parent = &pdev->dev;
298 ret = misc_register(&omap_wdt_miscdev);
302 pr_info("OMAP Watchdog Timer: initial timeout %d sec\n", timer_margin);
304 /* autogate OCP interface clock */
305 omap_writel(0x01, OMAP_WATCHDOG_SYS_CONFIG);
312 clk_put(mpu_wdt_ick);
314 clk_put(mpu_wdt_fck);
315 release_resource(mem);
319 static void omap_wdt_shutdown(struct platform_device *pdev)
324 static int omap_wdt_remove(struct platform_device *pdev)
326 struct resource *mem = platform_get_drvdata(pdev);
327 misc_deregister(&omap_wdt_miscdev);
328 release_resource(mem);
332 clk_put(mpu_wdt_ick);
334 clk_put(mpu_wdt_fck);
340 /* REVISIT ... not clear this is the best way to handle system suspend; and
341 * it's very inappropriate for selective device suspend (e.g. suspending this
342 * through sysfs rather than by stopping the watchdog daemon). Also, this
343 * may not play well enough with NOWAYOUT...
346 static int omap_wdt_suspend(struct platform_device *pdev, pm_message_t state)
353 static int omap_wdt_resume(struct platform_device *pdev)
355 if (omap_wdt_users) {
363 #define omap_wdt_suspend NULL
364 #define omap_wdt_resume NULL
367 static struct platform_driver omap_wdt_driver = {
368 .probe = omap_wdt_probe,
369 .remove = omap_wdt_remove,
370 .shutdown = omap_wdt_shutdown,
371 .suspend = omap_wdt_suspend,
372 .resume = omap_wdt_resume,
374 .owner = THIS_MODULE,
379 static int __init omap_wdt_init(void)
381 spin_lock_init(&wdt_lock);
382 return platform_driver_register(&omap_wdt_driver);
385 static void __exit omap_wdt_exit(void)
387 platform_driver_unregister(&omap_wdt_driver);
390 module_init(omap_wdt_init);
391 module_exit(omap_wdt_exit);
393 MODULE_AUTHOR("George G. Davis");
394 MODULE_LICENSE("GPL");
395 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
396 MODULE_ALIAS("platform:omap_wdt");