2 * mpc8xxx_wdt.c - MPC8xx/MPC83xx/MPC86xx watchdog userspace interface
4 * Authors: Dave Updegraff <dave@cray.org>
5 * Kumar Gala <galak@kernel.crashing.org>
6 * Attribution: from 83xx_wst: Florian Schirmer <jolt@tuxbox.org>
8 * Copyright (c) 2008 MontaVista Software, Inc.
9 * Anton Vorontsov <avorontsov@ru.mvista.com>
11 * Note: it appears that you can only actually ENABLE or DISABLE the thing
12 * once after POR. Once enabled, you cannot disable, and vice versa.
14 * This program is free software; you can redistribute it and/or modify it
15 * under the terms of the GNU General Public License as published by the
16 * Free Software Foundation; either version 2 of the License, or (at your
17 * option) any later version.
21 #include <linux/init.h>
22 #include <linux/kernel.h>
23 #include <linux/timer.h>
24 #include <linux/miscdevice.h>
25 #include <linux/of_platform.h>
26 #include <linux/module.h>
27 #include <linux/watchdog.h>
29 #include <linux/uaccess.h>
30 #include <sysdev/fsl_soc.h>
34 __be32 swcrr; /* System watchdog control register */
35 #define SWCRR_SWTC 0xFFFF0000 /* Software Watchdog Time Count. */
36 #define SWCRR_SWEN 0x00000004 /* Watchdog Enable bit. */
37 #define SWCRR_SWRI 0x00000002 /* Software Watchdog Reset/Interrupt Select bit.*/
38 #define SWCRR_SWPR 0x00000001 /* Software Watchdog Counter Prescale bit. */
39 __be32 swcnr; /* System watchdog count register */
41 __be16 swsrr; /* System watchdog service register */
45 struct mpc8xxx_wdt_type {
50 static struct mpc8xxx_wdt __iomem *wd_base;
51 static int mpc8xxx_wdt_init_late(void);
53 static u16 timeout = 0xffff;
54 module_param(timeout, ushort, 0);
55 MODULE_PARM_DESC(timeout,
56 "Watchdog timeout in ticks. (0<timeout<65536, default=65535)");
59 module_param(reset, bool, 0);
60 MODULE_PARM_DESC(reset,
61 "Watchdog Interrupt/Reset Mode. 0 = interrupt, 1 = reset");
63 static int nowayout = WATCHDOG_NOWAYOUT;
64 module_param(nowayout, int, 0);
65 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
66 "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
69 * We always prescale, but if someone really doesn't want to they can set this
72 static int prescale = 1;
73 static unsigned int timeout_sec;
75 static unsigned long wdt_is_open;
76 static DEFINE_SPINLOCK(wdt_spinlock);
78 static void mpc8xxx_wdt_keepalive(void)
81 spin_lock(&wdt_spinlock);
82 out_be16(&wd_base->swsrr, 0x556c);
83 out_be16(&wd_base->swsrr, 0xaa39);
84 spin_unlock(&wdt_spinlock);
87 static void mpc8xxx_wdt_timer_ping(unsigned long arg);
88 static DEFINE_TIMER(wdt_timer, mpc8xxx_wdt_timer_ping, 0, 0);
90 static void mpc8xxx_wdt_timer_ping(unsigned long arg)
92 mpc8xxx_wdt_keepalive();
93 /* We're pinging it twice faster than needed, just to be sure. */
94 mod_timer(&wdt_timer, jiffies + HZ * timeout_sec / 2);
97 static void mpc8xxx_wdt_pr_warn(const char *msg)
99 pr_crit("mpc8xxx_wdt: %s, expect the %s soon!\n", msg,
100 reset ? "reset" : "machine check exception");
103 static ssize_t mpc8xxx_wdt_write(struct file *file, const char __user *buf,
104 size_t count, loff_t *ppos)
107 mpc8xxx_wdt_keepalive();
111 static int mpc8xxx_wdt_open(struct inode *inode, struct file *file)
113 u32 tmp = SWCRR_SWEN;
114 if (test_and_set_bit(0, &wdt_is_open))
117 /* Once we start the watchdog we can't stop it */
119 __module_get(THIS_MODULE);
121 /* Good, fire up the show */
127 tmp |= timeout << 16;
129 out_be32(&wd_base->swcrr, tmp);
131 del_timer_sync(&wdt_timer);
133 return nonseekable_open(inode, file);
136 static int mpc8xxx_wdt_release(struct inode *inode, struct file *file)
139 mpc8xxx_wdt_timer_ping(0);
141 mpc8xxx_wdt_pr_warn("watchdog closed");
142 clear_bit(0, &wdt_is_open);
146 static long mpc8xxx_wdt_ioctl(struct file *file, unsigned int cmd,
149 void __user *argp = (void __user *)arg;
150 int __user *p = argp;
151 static const struct watchdog_info ident = {
152 .options = WDIOF_KEEPALIVEPING,
153 .firmware_version = 1,
154 .identity = "MPC8xxx",
158 case WDIOC_GETSUPPORT:
159 return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
160 case WDIOC_GETSTATUS:
161 case WDIOC_GETBOOTSTATUS:
162 return put_user(0, p);
163 case WDIOC_KEEPALIVE:
164 mpc8xxx_wdt_keepalive();
166 case WDIOC_GETTIMEOUT:
167 return put_user(timeout_sec, p);
173 static const struct file_operations mpc8xxx_wdt_fops = {
174 .owner = THIS_MODULE,
176 .write = mpc8xxx_wdt_write,
177 .unlocked_ioctl = mpc8xxx_wdt_ioctl,
178 .open = mpc8xxx_wdt_open,
179 .release = mpc8xxx_wdt_release,
182 static struct miscdevice mpc8xxx_wdt_miscdev = {
183 .minor = WATCHDOG_MINOR,
185 .fops = &mpc8xxx_wdt_fops,
188 static int __devinit mpc8xxx_wdt_probe(struct of_device *ofdev,
189 const struct of_device_id *match)
192 struct device_node *np = ofdev->dev.of_node;
193 struct mpc8xxx_wdt_type *wdt_type = match->data;
194 u32 freq = fsl_get_sys_freq();
197 if (!freq || freq == -1)
200 wd_base = of_iomap(np, 0);
204 enabled = in_be32(&wd_base->swcrr) & SWCRR_SWEN;
205 if (!enabled && wdt_type->hw_enabled) {
206 pr_info("mpc8xxx_wdt: could not be enabled in software\n");
211 /* Calculate the timeout in seconds */
213 timeout_sec = (timeout * wdt_type->prescaler) / freq;
215 timeout_sec = timeout / freq;
218 ret = mpc8xxx_wdt_init_late();
223 pr_info("WDT driver for MPC8xxx initialized. mode:%s timeout=%d "
224 "(%d seconds)\n", reset ? "reset" : "interrupt", timeout,
228 * If the watchdog was previously enabled or we're running on
229 * MPC8xxx, we should ping the wdt from the kernel until the
230 * userspace handles it.
233 mpc8xxx_wdt_timer_ping(0);
241 static int __devexit mpc8xxx_wdt_remove(struct of_device *ofdev)
243 mpc8xxx_wdt_pr_warn("watchdog removed");
244 del_timer_sync(&wdt_timer);
245 misc_deregister(&mpc8xxx_wdt_miscdev);
251 static const struct of_device_id mpc8xxx_wdt_match[] = {
253 .compatible = "mpc83xx_wdt",
254 .data = &(struct mpc8xxx_wdt_type) {
255 .prescaler = 0x10000,
259 .compatible = "fsl,mpc8610-wdt",
260 .data = &(struct mpc8xxx_wdt_type) {
261 .prescaler = 0x10000,
266 .compatible = "fsl,mpc823-wdt",
267 .data = &(struct mpc8xxx_wdt_type) {
273 MODULE_DEVICE_TABLE(of, mpc8xxx_wdt_match);
275 static struct of_platform_driver mpc8xxx_wdt_driver = {
276 .probe = mpc8xxx_wdt_probe,
277 .remove = __devexit_p(mpc8xxx_wdt_remove),
279 .name = "mpc8xxx_wdt",
280 .owner = THIS_MODULE,
281 .of_match_table = mpc8xxx_wdt_match,
286 * We do wdt initialization in two steps: arch_initcall probes the wdt
287 * very early to start pinging the watchdog (misc devices are not yet
288 * available), and later module_init() just registers the misc device.
290 static int mpc8xxx_wdt_init_late(void)
297 ret = misc_register(&mpc8xxx_wdt_miscdev);
299 pr_err("cannot register miscdev on minor=%d (err=%d)\n",
300 WATCHDOG_MINOR, ret);
306 module_init(mpc8xxx_wdt_init_late);
309 static int __init mpc8xxx_wdt_init(void)
311 return of_register_platform_driver(&mpc8xxx_wdt_driver);
313 arch_initcall(mpc8xxx_wdt_init);
315 static void __exit mpc8xxx_wdt_exit(void)
317 of_unregister_platform_driver(&mpc8xxx_wdt_driver);
319 module_exit(mpc8xxx_wdt_exit);
321 MODULE_AUTHOR("Dave Updegraff, Kumar Gala");
322 MODULE_DESCRIPTION("Driver for watchdog timer in MPC8xx/MPC83xx/MPC86xx "
324 MODULE_LICENSE("GPL");
325 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);