static ssize_t wafwdt_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) { if (count) { if (!nowayout) { size_t i; expect_close = 0; for (i = 0; i != count; i++) { char c; if (get_user(c, buf + i)) return -EFAULT; if (c == 'V') expect_close = 42; } } wafwdt_ping(); } return count; }
static ssize_t wafwdt_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) { /* See if we got the magic character 'V' and reload the timer */ if (count) { if (!nowayout) { size_t i; /* In case it was set long ago */ expect_close = 0; /* scan to see whether or not we got the magic character */ for (i = 0; i != count; i++) { char c; if (get_user(c, buf + i)) return -EFAULT; if (c == 'V') expect_close = 42; } } /* Well, anyhow someone wrote to us, we should return that favour */ wafwdt_ping(); } return count; }
static long wafwdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { int new_timeout; void __user *argp = (void __user *)arg; int __user *p = argp; static const struct watchdog_info ident = { .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE, .firmware_version = 1, .identity = "Wafer 5823 WDT", }; switch (cmd) { case WDIOC_GETSUPPORT: if (copy_to_user(argp, &ident, sizeof(ident))) return -EFAULT; break; case WDIOC_GETSTATUS: case WDIOC_GETBOOTSTATUS: return put_user(0, p); case WDIOC_SETOPTIONS: { int options, retval = -EINVAL; if (get_user(options, p)) return -EFAULT; if (options & WDIOS_DISABLECARD) { wafwdt_start(); retval = 0; } if (options & WDIOS_ENABLECARD) { wafwdt_stop(); retval = 0; } return retval; } case WDIOC_KEEPALIVE: wafwdt_ping(); break; case WDIOC_SETTIMEOUT: if (get_user(new_timeout, p)) return -EFAULT; if ((new_timeout < 1) || (new_timeout > 255)) return -EINVAL; timeout = new_timeout; wafwdt_stop(); wafwdt_start(); case WDIOC_GETTIMEOUT: return put_user(timeout, p); default: return -ENOTTY; } return 0; } static int wafwdt_open(struct inode *inode, struct file *file) { if (test_and_set_bit(0, &wafwdt_is_open)) return -EBUSY; wafwdt_start(); return nonseekable_open(inode, file); } static int wafwdt_close(struct inode *inode, struct file *file) { if (expect_close == 42) wafwdt_stop(); else { printk(KERN_CRIT PFX "WDT device closed unexpectedly. WDT will not stop!\n"); wafwdt_ping(); } clear_bit(0, &wafwdt_is_open); expect_close = 0; return 0; } static int wafwdt_notify_sys(struct notifier_block *this, unsigned long code, void *unused) { if (code == SYS_DOWN || code == SYS_HALT) wafwdt_stop(); return NOTIFY_DONE; } static const struct file_operations wafwdt_fops = { .owner = THIS_MODULE, .llseek = no_llseek, .write = wafwdt_write, .unlocked_ioctl = wafwdt_ioctl, .open = wafwdt_open, .release = wafwdt_close, }; static struct miscdevice wafwdt_miscdev = { .minor = WATCHDOG_MINOR, .name = "watchdog", .fops = &wafwdt_fops, }; static struct notifier_block wafwdt_notifier = { .notifier_call = wafwdt_notify_sys, }; static int __init wafwdt_init(void) { int ret; printk(KERN_INFO "WDT driver for Wafer 5823 single board computer initialising.\n"); if (timeout < 1 || timeout > 255) { timeout = WD_TIMO; printk(KERN_INFO PFX "timeout value must be 1 <= x <= 255, using %d\n", timeout); } if (wdt_stop != wdt_start) { if (!request_region(wdt_stop, 1, "Wafer 5823 WDT")) { printk(KERN_ERR PFX "I/O address 0x%04x already in use\n", wdt_stop); ret = -EIO; goto error; } } if (!request_region(wdt_start, 1, "Wafer 5823 WDT")) { printk(KERN_ERR PFX "I/O address 0x%04x already in use\n", wdt_start); ret = -EIO; goto error2; } ret = register_reboot_notifier(&wafwdt_notifier); if (ret != 0) { printk(KERN_ERR PFX "cannot register reboot notifier (err=%d)\n", ret); goto error3; } ret = misc_register(&wafwdt_miscdev); if (ret != 0) { printk(KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n", WATCHDOG_MINOR, ret); goto error4; } printk(KERN_INFO PFX "initialized. timeout=%d sec (nowayout=%d)\n", timeout, nowayout); return ret; error4: unregister_reboot_notifier(&wafwdt_notifier); error3: release_region(wdt_start, 1); error2: if (wdt_stop != wdt_start) release_region(wdt_stop, 1); error: return ret; } static void __exit wafwdt_exit(void) { misc_deregister(&wafwdt_miscdev); unregister_reboot_notifier(&wafwdt_notifier); if (wdt_stop != wdt_start) release_region(wdt_stop, 1); release_region(wdt_start, 1); }