/* * Watchdog driver for SBC-FITPC2 board * * Author: Denis Turischev <denis@compulab.co.il> * * Adapted from the IXP2000 watchdog driver by Deepak Saxena. * * This file is licensed under the terms of the GNU General Public * License version 2. This program is licensed "as is" without any * warranty of any kind, whether express or implied. */ #define pr_fmt(fmt) KBUILD_MODNAME " WATCHDOG: " fmt #include <linux/module.h> #include <linux/types.h> #include <linux/miscdevice.h> #include <linux/watchdog.h> #include <linux/ioport.h> #include <linux/delay.h> #include <linux/fs.h> #include <linux/init.h> #include <linux/moduleparam.h> #include <linux/dmi.h> #include <linux/io.h> #include <linux/uaccess.h> static bool nowayout = WATCHDOG_NOWAYOUT; static unsigned int margin = 60; /* (secs) Default is 1 minute */ static unsigned long wdt_status; static DEFINE_MUTEX(wdt_lock); #define WDT_IN_USE 0 #define WDT_OK_TO_CLOSE 1 #define COMMAND_PORT 0x4c #define DATA_PORT 0x48 #define IFACE_ON_COMMAND 1 #define REBOOT_COMMAND 2 #define WATCHDOG_NAME "SBC-FITPC2 Watchdog" static void wdt_send_data(unsigned char command, unsigned char data) { outb(data, DATA_PORT); msleep(200); outb(command, COMMAND_PORT); msleep(100); } static void wdt_enable(void) { mutex_lock(&wdt_lock); wdt_send_data(IFACE_ON_COMMAND, 1); wdt_send_data(REBOOT_COMMAND, margin); mutex_unlock(&wdt_lock); } static void wdt_disable(void) { mutex_lock(&wdt_lock); wdt_send_data(IFACE_ON_COMMAND, 0); wdt_send_data(REBOOT_COMMAND, 0); mutex_unlock(&wdt_lock); } static int fitpc2_wdt_open(struct inode *inode, struct file *file) { if (test_and_set_bit(WDT_IN_USE, &wdt_status)) return -EBUSY; clear_bit(WDT_OK_TO_CLOSE, &wdt_status); wdt_enable(); return stream_open(inode, file); } static ssize_t fitpc2_wdt_write(struct file *file, const char *data, size_t len, loff_t *ppos) { size_t i; if (!len) return 0; if (nowayout) { len = 0; goto out; } clear_bit(WDT_OK_TO_CLOSE, &wdt_status); for (i = 0; i != len; i++) { char c; if (get_user(c, data + i)) return -EFAULT; if (c == 'V') set_bit(WDT_OK_TO_CLOSE, &wdt_status); } out: wdt_enable(); return len; } static const struct watchdog_info ident = { .options = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING, .identity = WATCHDOG_NAME, }; static long fitpc2_wdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { int ret = -ENOTTY; int time; switch (cmd) { case WDIOC_GETSUPPORT: ret = copy_to_user((struct watchdog_info *)arg, &ident, sizeof(ident)) ? -EFAULT : 0; break; case WDIOC_GETSTATUS: ret = put_user(0, (int *)arg); break; case WDIOC_GETBOOTSTATUS: ret = put_user(0, (int *)arg); break; case WDIOC_KEEPALIVE: wdt_enable(); ret = 0; break; case WDIOC_SETTIMEOUT: ret = get_user(time, (int *)arg); if (ret) break; if (time < 31 || time > 255) { ret = -EINVAL; break; } margin = time; wdt_enable(); /* Fall through */ case WDIOC_GETTIMEOUT: ret = put_user(margin, (int *)arg); break; } return ret; } static int fitpc2_wdt_release(struct inode *inode, struct file *file) { if (test_bit(WDT_OK_TO_CLOSE, &wdt_status)) { wdt_disable(); pr_info("Device disabled\n"); } else { pr_warn("Device closed unexpectedly - timer will not stop\n"); wdt_enable(); } clear_bit(WDT_IN_USE, &wdt_status); clear_bit(WDT_OK_TO_CLOSE, &wdt_status); return 0; } static const struct file_operations fitpc2_wdt_fops = { .owner = THIS_MODULE, .llseek = no_llseek, .write = fitpc2_wdt_write, .unlocked_ioctl = fitpc2_wdt_ioctl, .compat_ioctl = compat_ptr_ioctl, .open = fitpc2_wdt_open, .release = fitpc2_wdt_release, }; static struct miscdevice fitpc2_wdt_miscdev = { .minor = WATCHDOG_MINOR, .name = "watchdog", .fops = &fitpc2_wdt_fops, }; static int __init fitpc2_wdt_init(void) { int err; const char *brd_name; brd_name = dmi_get_system_info(DMI_BOARD_NAME); if (!brd_name || !strstr(brd_name, "SBC-FITPC2")) return -ENODEV; pr_info("%s found\n", brd_name); if (!request_region(COMMAND_PORT, 1, WATCHDOG_NAME)) { pr_err("I/O address 0x%04x already in use\n", COMMAND_PORT); return -EIO; } if (!request_region(DATA_PORT, 1, WATCHDOG_NAME)) { pr_err("I/O address 0x%04x already in use\n", DATA_PORT); err = -EIO; goto err_data_port; } if (margin < 31 || margin > 255) { pr_err("margin must be in range 31 - 255 seconds, you tried to set %d\n", margin); err = -EINVAL; goto err_margin; } err = misc_register(&fitpc2_wdt_miscdev); if (err) { pr_err("cannot register miscdev on minor=%d (err=%d)\n", WATCHDOG_MINOR, err); goto err_margin; } return 0; err_margin: release_region(DATA_PORT, 1); err_data_port: release_region(COMMAND_PORT, 1); return err; } static void __exit fitpc2_wdt_exit(void) { misc_deregister(&fitpc2_wdt_miscdev); release_region(DATA_PORT, 1); release_region(COMMAND_PORT, 1); } module_init(fitpc2_wdt_init); module_exit(fitpc2_wdt_exit); MODULE_AUTHOR("Denis Turischev <denis@compulab.co.il>"); MODULE_DESCRIPTION("SBC-FITPC2 Watchdog"); module_param(margin, int, 0); MODULE_PARM_DESC(margin, "Watchdog margin in seconds (default 60s)"); module_param(nowayout, bool, 0); MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started"); MODULE_LICENSE("GPL");