/* * NANO7240 SBC Watchdog device driver * * Based on w83877f.c by Scott Jennings, * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation; * * Software distributed under the License is distributed on an "AS IS" * basis, WITHOUT WARRANTY OF ANY KIND, either express or * implied. See the License for the specific language governing * rights and limitations under the License. * * (c) Copyright 2007 Gilles GIGAN <gilles.gigan@jcu.edu.au> * */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include <linux/fs.h> #include <linux/init.h> #include <linux/ioport.h> #include <linux/jiffies.h> #include <linux/module.h> #include <linux/moduleparam.h> #include <linux/miscdevice.h> #include <linux/notifier.h> #include <linux/reboot.h> #include <linux/types.h> #include <linux/watchdog.h> #include <linux/io.h> #include <linux/uaccess.h> #include <linux/atomic.h> #define SBC7240_ENABLE_PORT 0x443 #define SBC7240_DISABLE_PORT 0x043 #define SBC7240_SET_TIMEOUT_PORT SBC7240_ENABLE_PORT #define SBC7240_MAGIC_CHAR 'V' #define SBC7240_TIMEOUT 30 #define SBC7240_MAX_TIMEOUT 255 static int timeout = SBC7240_TIMEOUT; /* in seconds */ module_param(timeout, int, 0); MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. (1<=timeout<=" __MODULE_STRING(SBC7240_MAX_TIMEOUT) ", default=" __MODULE_STRING(SBC7240_TIMEOUT) ")"); static bool nowayout = WATCHDOG_NOWAYOUT; module_param(nowayout, bool, 0); MODULE_PARM_DESC(nowayout, "Disable watchdog when closing device file"); #define SBC7240_OPEN_STATUS_BIT 0 #define SBC7240_ENABLED_STATUS_BIT 1 #define SBC7240_EXPECT_CLOSE_STATUS_BIT 2 static unsigned long wdt_status; /* * Utility routines */ static void wdt_disable(void) { /* disable the watchdog */ if (test_and_clear_bit(SBC7240_ENABLED_STATUS_BIT, &wdt_status)) { inb_p(SBC7240_DISABLE_PORT); pr_info("Watchdog timer is now disabled\n"); } } static void wdt_enable(void) { /* enable the watchdog */ if (!test_and_set_bit(SBC7240_ENABLED_STATUS_BIT, &wdt_status)) { inb_p(SBC7240_ENABLE_PORT); pr_info("Watchdog timer is now enabled\n"); } } static int wdt_set_timeout(int t) { if (t < 1 || t > SBC7240_MAX_TIMEOUT) { pr_err("timeout value must be 1<=x<=%d\n", SBC7240_MAX_TIMEOUT); return -1; } /* set the timeout */ outb_p((unsigned)t, SBC7240_SET_TIMEOUT_PORT); timeout = t; pr_info("timeout set to %d seconds\n", t); return 0; } /* Whack the dog */ static inline void wdt_keepalive(void) { if (test_bit(SBC7240_ENABLED_STATUS_BIT, &wdt_status)) inb_p(SBC7240_ENABLE_PORT); } /* * /dev/watchdog handling */ static ssize_t fop_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) { size_t i; char c; if (count) { if (!nowayout) { clear_bit(SBC7240_EXPECT_CLOSE_STATUS_BIT, &wdt_status); /* is there a magic char ? */ for (i = 0; i != count; i++) { if (get_user(c, buf + i)) return -EFAULT; if (c == SBC7240_MAGIC_CHAR) { set_bit(SBC7240_EXPECT_CLOSE_STATUS_BIT, &wdt_status); break; } } } wdt_keepalive(); } return count; } static int fop_open(struct inode *inode, struct file *file) { if (test_and_set_bit(SBC7240_OPEN_STATUS_BIT, &wdt_status)) return -EBUSY; wdt_enable(); return nonseekable_open(inode, file); } static int fop_close(struct inode *inode, struct file *file) { if (test_and_clear_bit(SBC7240_EXPECT_CLOSE_STATUS_BIT, &wdt_status) || !nowayout) { wdt_disable(); } else { pr_crit("Unexpected close, not stopping watchdog!\n"); wdt_keepalive(); } clear_bit(SBC7240_OPEN_STATUS_BIT, &wdt_status); return 0; } static const struct watchdog_info ident = { .options = WDIOF_KEEPALIVEPING| WDIOF_SETTIMEOUT| WDIOF_MAGICCLOSE, .firmware_version = 1, .identity = "SBC7240", }; static long fop_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { switch (cmd) { case WDIOC_GETSUPPORT: return copy_to_user((void __user *)arg, &ident, sizeof(ident)) ? -EFAULT : 0; case WDIOC_GETSTATUS: case WDIOC_GETBOOTSTATUS: return put_user(0, (int __user *)arg); case WDIOC_SETOPTIONS: { int options; int retval = -EINVAL; if (get_user(options, (int __user *)arg)) return -EFAULT; if (options & WDIOS_DISABLECARD) { wdt_disable(); retval = 0; } if (options & WDIOS_ENABLECARD) { wdt_enable(); retval = 0; } return retval; } case WDIOC_KEEPALIVE: wdt_keepalive(); return 0; case WDIOC_SETTIMEOUT: { int new_timeout; if (get_user(new_timeout, (int __user *)arg)) return -EFAULT; if (wdt_set_timeout(new_timeout)) return -EINVAL; /* Fall through */ } case WDIOC_GETTIMEOUT: return put_user(timeout, (int __user *)arg); default: return -ENOTTY; } } static const struct file_operations wdt_fops = { .owner = THIS_MODULE, .llseek = no_llseek, .write = fop_write, .open = fop_open, .release = fop_close, .unlocked_ioctl = fop_ioctl, }; static struct miscdevice wdt_miscdev = { .minor = WATCHDOG_MINOR, .name = "watchdog", .fops = &wdt_fops, }; /* * Notifier for system down */ static int wdt_notify_sys(struct notifier_block *this, unsigned long code, void *unused) { if (code == SYS_DOWN || code == SYS_HALT) wdt_disable(); return NOTIFY_DONE; } static struct notifier_block wdt_notifier = { .notifier_call = wdt_notify_sys, }; static void __exit sbc7240_wdt_unload(void) { pr_info("Removing watchdog\n"); misc_deregister(&wdt_miscdev); unregister_reboot_notifier(&wdt_notifier); release_region(SBC7240_ENABLE_PORT, 1); } static int __init sbc7240_wdt_init(void) { int rc = -EBUSY; if (!request_region(SBC7240_ENABLE_PORT, 1, "SBC7240 WDT")) { pr_err("I/O address 0x%04x already in use\n", SBC7240_ENABLE_PORT); rc = -EIO; goto err_out; } /* The IO port 0x043 used to disable the watchdog * is already claimed by the system timer, so we * can't request_region() it ...*/ if (timeout < 1 || timeout > SBC7240_MAX_TIMEOUT) { timeout = SBC7240_TIMEOUT; pr_info("timeout value must be 1<=x<=%d, using %d\n", SBC7240_MAX_TIMEOUT, timeout); } wdt_set_timeout(timeout); wdt_disable(); rc = register_reboot_notifier(&wdt_notifier); if (rc) { pr_err("cannot register reboot notifier (err=%d)\n", rc); goto err_out_region; } rc = misc_register(&wdt_miscdev); if (rc) { pr_err("cannot register miscdev on minor=%d (err=%d)\n", wdt_miscdev.minor, rc); goto err_out_reboot_notifier; } pr_info("Watchdog driver for SBC7240 initialised (nowayout=%d)\n", nowayout); return 0; err_out_reboot_notifier: unregister_reboot_notifier(&wdt_notifier); err_out_region: release_region(SBC7240_ENABLE_PORT, 1); err_out: return rc; } module_init(sbc7240_wdt_init); module_exit(sbc7240_wdt_unload); MODULE_AUTHOR("Gilles Gigan"); MODULE_DESCRIPTION("Watchdog device driver for single board" " computers EPIC Nano 7240 from iEi"); MODULE_LICENSE("GPL");