1 /* riowd.c - driver for hw watchdog inside Super I/O of RIO
3 * Copyright (C) 2001, 2008 David S. Miller (davem@davemloft.net)
6 #include <linux/kernel.h>
7 #include <linux/module.h>
8 #include <linux/types.h>
10 #include <linux/errno.h>
11 #include <linux/init.h>
12 #include <linux/miscdevice.h>
13 #include <linux/watchdog.h>
15 #include <linux/of_device.h>
17 #include <linux/uaccess.h>
18 #include <linux/slab.h>
21 /* RIO uses the NatSemi Super I/O power management logical device
24 * When the watchdog triggers, it asserts a line to the BBC (Boot Bus
25 * Controller) of the machine. The BBC can only be configured to
26 * trigger a power-on reset when the signal is asserted. The BBC
27 * can be configured to ignore the signal entirely as well.
29 * The only Super I/O device register we care about is at index
30 * 0x05 (WDTO_INDEX) which is the watchdog time-out in minutes (1-255).
31 * If set to zero, this disables the watchdog. When set, the system
32 * must periodically (before watchdog expires) clear (set to zero) and
33 * re-set the watchdog else it will trigger.
35 * There are two other indexed watchdog registers inside this Super I/O
36 * logical device, but they are unused. The first, at index 0x06 is
37 * the watchdog control and can be used to make the watchdog timer re-set
38 * when the PS/2 mouse or serial lines show activity. The second, at
39 * index 0x07 is merely a sampling of the line from the watchdog to the
42 * The watchdog device generates no interrupts.
45 MODULE_AUTHOR("David S. Miller <davem@davemloft.net>");
46 MODULE_DESCRIPTION("Hardware watchdog driver for Sun RIO");
47 MODULE_SUPPORTED_DEVICE("watchdog");
48 MODULE_LICENSE("GPL");
50 #define DRIVER_NAME "riowd"
51 #define PFX DRIVER_NAME ": "
58 static struct riowd *riowd_device;
60 #define WDTO_INDEX 0x05
62 static int riowd_timeout = 1; /* in minutes */
63 module_param(riowd_timeout, int, 0);
64 MODULE_PARM_DESC(riowd_timeout, "Watchdog timeout in minutes");
66 static void riowd_writereg(struct riowd *p, u8 val, int index)
70 spin_lock_irqsave(&p->lock, flags);
71 writeb(index, p->regs + 0);
72 writeb(val, p->regs + 1);
73 spin_unlock_irqrestore(&p->lock, flags);
76 static int riowd_open(struct inode *inode, struct file *filp)
78 nonseekable_open(inode, filp);
82 static int riowd_release(struct inode *inode, struct file *filp)
87 static long riowd_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
89 static const struct watchdog_info info = {
90 .options = WDIOF_SETTIMEOUT,
91 .firmware_version = 1,
92 .identity = DRIVER_NAME,
94 void __user *argp = (void __user *)arg;
95 struct riowd *p = riowd_device;
100 case WDIOC_GETSUPPORT:
101 if (copy_to_user(argp, &info, sizeof(info)))
105 case WDIOC_GETSTATUS:
106 case WDIOC_GETBOOTSTATUS:
107 if (put_user(0, (int __user *)argp))
111 case WDIOC_KEEPALIVE:
112 riowd_writereg(p, riowd_timeout, WDTO_INDEX);
115 case WDIOC_SETOPTIONS:
116 if (copy_from_user(&options, argp, sizeof(options)))
119 if (options & WDIOS_DISABLECARD)
120 riowd_writereg(p, 0, WDTO_INDEX);
121 else if (options & WDIOS_ENABLECARD)
122 riowd_writereg(p, riowd_timeout, WDTO_INDEX);
128 case WDIOC_SETTIMEOUT:
129 if (get_user(new_margin, (int __user *)argp))
131 if ((new_margin < 60) || (new_margin > (255 * 60)))
133 riowd_timeout = (new_margin + 59) / 60;
134 riowd_writereg(p, riowd_timeout, WDTO_INDEX);
137 case WDIOC_GETTIMEOUT:
138 return put_user(riowd_timeout * 60, (int __user *)argp);
147 static ssize_t riowd_write(struct file *file, const char __user *buf,
148 size_t count, loff_t *ppos)
150 struct riowd *p = riowd_device;
153 riowd_writereg(p, riowd_timeout, WDTO_INDEX);
160 static const struct file_operations riowd_fops = {
161 .owner = THIS_MODULE,
163 .unlocked_ioctl = riowd_ioctl,
165 .write = riowd_write,
166 .release = riowd_release,
169 static struct miscdevice riowd_miscdev = {
170 .minor = WATCHDOG_MINOR,
175 static int __devinit riowd_probe(struct platform_device *op)
184 p = kzalloc(sizeof(*p), GFP_KERNEL);
188 spin_lock_init(&p->lock);
190 p->regs = of_ioremap(&op->resource[0], 0, 2, DRIVER_NAME);
192 printk(KERN_ERR PFX "Cannot map registers.\n");
195 /* Make miscdev useable right away */
198 err = misc_register(&riowd_miscdev);
200 printk(KERN_ERR PFX "Cannot register watchdog misc device.\n");
204 printk(KERN_INFO PFX "Hardware watchdog [%i minutes], "
205 "regs at %p\n", riowd_timeout, p->regs);
207 dev_set_drvdata(&op->dev, p);
212 of_iounmap(&op->resource[0], p->regs, 2);
221 static int __devexit riowd_remove(struct platform_device *op)
223 struct riowd *p = dev_get_drvdata(&op->dev);
225 misc_deregister(&riowd_miscdev);
226 of_iounmap(&op->resource[0], p->regs, 2);
232 static const struct of_device_id riowd_match[] = {
238 MODULE_DEVICE_TABLE(of, riowd_match);
240 static struct platform_driver riowd_driver = {
243 .owner = THIS_MODULE,
244 .of_match_table = riowd_match,
246 .probe = riowd_probe,
247 .remove = __devexit_p(riowd_remove),
250 static int __init riowd_init(void)
252 return platform_driver_register(&riowd_driver);
255 static void __exit riowd_exit(void)
257 platform_driver_unregister(&riowd_driver);
260 module_init(riowd_init);
261 module_exit(riowd_exit);