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>
20 /* RIO uses the NatSemi Super I/O power management logical device
23 * When the watchdog triggers, it asserts a line to the BBC (Boot Bus
24 * Controller) of the machine. The BBC can only be configured to
25 * trigger a power-on reset when the signal is asserted. The BBC
26 * can be configured to ignore the signal entirely as well.
28 * The only Super I/O device register we care about is at index
29 * 0x05 (WDTO_INDEX) which is the watchdog time-out in minutes (1-255).
30 * If set to zero, this disables the watchdog. When set, the system
31 * must periodically (before watchdog expires) clear (set to zero) and
32 * re-set the watchdog else it will trigger.
34 * There are two other indexed watchdog registers inside this Super I/O
35 * logical device, but they are unused. The first, at index 0x06 is
36 * the watchdog control and can be used to make the watchdog timer re-set
37 * when the PS/2 mouse or serial lines show activity. The second, at
38 * index 0x07 is merely a sampling of the line from the watchdog to the
41 * The watchdog device generates no interrupts.
44 MODULE_AUTHOR("David S. Miller <davem@davemloft.net>");
45 MODULE_DESCRIPTION("Hardware watchdog driver for Sun RIO");
46 MODULE_SUPPORTED_DEVICE("watchdog");
47 MODULE_LICENSE("GPL");
49 #define DRIVER_NAME "riowd"
50 #define PFX DRIVER_NAME ": "
57 static struct riowd *riowd_device;
59 #define WDTO_INDEX 0x05
61 static int riowd_timeout = 1; /* in minutes */
62 module_param(riowd_timeout, int, 0);
63 MODULE_PARM_DESC(riowd_timeout, "Watchdog timeout in minutes");
65 static void riowd_writereg(struct riowd *p, u8 val, int index)
69 spin_lock_irqsave(&p->lock, flags);
70 writeb(index, p->regs + 0);
71 writeb(val, p->regs + 1);
72 spin_unlock_irqrestore(&p->lock, flags);
75 static int riowd_open(struct inode *inode, struct file *filp)
77 nonseekable_open(inode, filp);
81 static int riowd_release(struct inode *inode, struct file *filp)
86 static long riowd_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
88 static const struct watchdog_info info = {
89 .options = WDIOF_SETTIMEOUT,
90 .firmware_version = 1,
91 .identity = DRIVER_NAME,
93 void __user *argp = (void __user *)arg;
94 struct riowd *p = riowd_device;
99 case WDIOC_GETSUPPORT:
100 if (copy_to_user(argp, &info, sizeof(info)))
104 case WDIOC_GETSTATUS:
105 case WDIOC_GETBOOTSTATUS:
106 if (put_user(0, (int __user *)argp))
110 case WDIOC_KEEPALIVE:
111 riowd_writereg(p, riowd_timeout, WDTO_INDEX);
114 case WDIOC_SETOPTIONS:
115 if (copy_from_user(&options, argp, sizeof(options)))
118 if (options & WDIOS_DISABLECARD)
119 riowd_writereg(p, 0, WDTO_INDEX);
120 else if (options & WDIOS_ENABLECARD)
121 riowd_writereg(p, riowd_timeout, WDTO_INDEX);
127 case WDIOC_SETTIMEOUT:
128 if (get_user(new_margin, (int __user *)argp))
130 if ((new_margin < 60) || (new_margin > (255 * 60)))
132 riowd_timeout = (new_margin + 59) / 60;
133 riowd_writereg(p, riowd_timeout, WDTO_INDEX);
136 case WDIOC_GETTIMEOUT:
137 return put_user(riowd_timeout * 60, (int __user *)argp);
146 static ssize_t riowd_write(struct file *file, const char __user *buf,
147 size_t count, loff_t *ppos)
149 struct riowd *p = riowd_device;
152 riowd_writereg(p, riowd_timeout, WDTO_INDEX);
159 static const struct file_operations riowd_fops = {
160 .owner = THIS_MODULE,
162 .unlocked_ioctl = riowd_ioctl,
164 .write = riowd_write,
165 .release = riowd_release,
168 static struct miscdevice riowd_miscdev = {
169 .minor = WATCHDOG_MINOR,
174 static int __devinit riowd_probe(struct of_device *op,
175 const struct of_device_id *match)
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 of_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 of_platform_driver riowd_driver = {
242 .match_table = riowd_match,
243 .probe = riowd_probe,
244 .remove = __devexit_p(riowd_remove),
247 static int __init riowd_init(void)
249 return of_register_driver(&riowd_driver, &of_bus_type);
252 static void __exit riowd_exit(void)
254 of_unregister_driver(&riowd_driver);
257 module_init(riowd_init);
258 module_exit(riowd_exit);