drivers/watchdog/mixcomwd.c

0001 // SPDX-License-Identifier: GPL-2.0-or-later
0002 /*
0003  * MixCom Watchdog: A Simple Hardware Watchdog Device
0004  * Based on Softdog driver by Alan Cox and PC Watchdog driver by Ken Hollis
0005  *
0006  * Author: Gergely Madarasz <gorgo@itc.hu>
0007  *
0008  * Copyright (c) 1999 ITConsult-Pro Co. <info@itc.hu>
0009  *
0010  * Version 0.1 (99/04/15):
0011  *      - first version
0012  *
0013  * Version 0.2 (99/06/16):
0014  *      - added kernel timer watchdog ping after close
0015  *        since the hardware does not support watchdog shutdown
0016  *
0017  * Version 0.3 (99/06/21):
0018  *      - added WDIOC_GETSTATUS and WDIOC_GETSUPPORT ioctl calls
0019  *
0020  * Version 0.3.1 (99/06/22):
0021  *      - allow module removal while internal timer is active,
0022  *        print warning about probable reset
0023  *
0024  * Version 0.4 (99/11/15):
0025  *      - support for one more type board
0026  *
0027  * Version 0.5 (2001/12/14) Matt Domsch <Matt_Domsch@dell.com>
0028  *      - added nowayout module option to override
0029  *        CONFIG_WATCHDOG_NOWAYOUT
0030  *
0031  * Version 0.6 (2002/04/12): Rob Radez <rob@osinvestor.com>
0032  *      - make mixcomwd_opened unsigned,
0033  *        removed lock_kernel/unlock_kernel from mixcomwd_release,
0034  *        modified ioctl a bit to conform to API
0035  */
0036
0037 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
0038
0039 #define VERSION "0.6"
0040 #define WATCHDOG_NAME "mixcomwd"
0041
0042 #include <linux/module.h>
0043 #include <linux/moduleparam.h>
0044 #include <linux/types.h>
0045 #include <linux/miscdevice.h>
0046 #include <linux/ioport.h>
0047 #include <linux/watchdog.h>
0048 #include <linux/fs.h>
0049 #include <linux/reboot.h>
0050 #include <linux/init.h>
0051 #include <linux/jiffies.h>
0052 #include <linux/timer.h>
0053 #include <linux/uaccess.h>
0054 #include <linux/io.h>
0055
0056 /*
0057  * We have two types of cards that can be probed:
0058  * 1) The Mixcom cards: these cards can be found at addresses
0059  *    0x180, 0x280, 0x380 with an additional offset of 0xc10.
0060  *    (Or 0xd90, 0xe90, 0xf90).
0061  * 2) The FlashCOM cards: these cards can be set up at
0062  *    0x300 -> 0x378, in 0x8 jumps with an offset of 0x04.
0063  *    (Or 0x304 -> 0x37c in 0x8 jumps).
0064  *    Each card has it's own ID.
0065  */
0066 #define MIXCOM_ID 0x11
0067 #define FLASHCOM_ID 0x18
0068 static struct {
0069     int ioport;
0070     int id;
0071 } mixcomwd_io_info[] = {
0072     /* The Mixcom cards */
0073     {0x0d90, MIXCOM_ID},
0074     {0x0e90, MIXCOM_ID},
0075     {0x0f90, MIXCOM_ID},
0076     /* The FlashCOM cards */
0077     {0x0304, FLASHCOM_ID},
0078     {0x030c, FLASHCOM_ID},
0079     {0x0314, FLASHCOM_ID},
0080     {0x031c, FLASHCOM_ID},
0081     {0x0324, FLASHCOM_ID},
0082     {0x032c, FLASHCOM_ID},
0083     {0x0334, FLASHCOM_ID},
0084     {0x033c, FLASHCOM_ID},
0085     {0x0344, FLASHCOM_ID},
0086     {0x034c, FLASHCOM_ID},
0087     {0x0354, FLASHCOM_ID},
0088     {0x035c, FLASHCOM_ID},
0089     {0x0364, FLASHCOM_ID},
0090     {0x036c, FLASHCOM_ID},
0091     {0x0374, FLASHCOM_ID},
0092     {0x037c, FLASHCOM_ID},
0093     /* The end of the list */
0094     {0x0000, 0},
0095 };
0096
0097 static void mixcomwd_timerfun(struct timer_list *unused);
0098
0099 static unsigned long mixcomwd_opened; /* long req'd for setbit --RR */
0100
0101 static int watchdog_port;
0102 static int mixcomwd_timer_alive;
0103 static DEFINE_TIMER(mixcomwd_timer, mixcomwd_timerfun);
0104 static char expect_close;
0105
0106 static bool nowayout = WATCHDOG_NOWAYOUT;
0107 module_param(nowayout, bool, 0);
0108 MODULE_PARM_DESC(nowayout,
0109         "Watchdog cannot be stopped once started (default="
0110                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
0111
0112 static void mixcomwd_ping(void)
0113 {
0114     outb_p(55, watchdog_port);
0115     return;
0116 }
0117
0118 static void mixcomwd_timerfun(struct timer_list *unused)
0119 {
0120     mixcomwd_ping();
0121     mod_timer(&mixcomwd_timer, jiffies + 5 * HZ);
0122 }
0123
0124 /*
0125  *  Allow only one person to hold it open
0126  */
0127
0128 static int mixcomwd_open(struct inode *inode, struct file *file)
0129 {
0130     if (test_and_set_bit(0, &mixcomwd_opened))
0131         return -EBUSY;
0132
0133     mixcomwd_ping();
0134
0135     if (nowayout)
0136         /*
0137          * fops_get() code via open() has already done
0138          * a try_module_get() so it is safe to do the
0139          * __module_get().
0140          */
0141         __module_get(THIS_MODULE);
0142     else {
0143         if (mixcomwd_timer_alive) {
0144             del_timer(&mixcomwd_timer);
0145             mixcomwd_timer_alive = 0;
0146         }
0147     }
0148     return stream_open(inode, file);
0149 }
0150
0151 static int mixcomwd_release(struct inode *inode, struct file *file)
0152 {
0153     if (expect_close == 42) {
0154         if (mixcomwd_timer_alive) {
0155             pr_err("release called while internal timer alive\n");
0156             return -EBUSY;
0157         }
0158         mixcomwd_timer_alive = 1;
0159         mod_timer(&mixcomwd_timer, jiffies + 5 * HZ);
0160     } else
0161         pr_crit("WDT device closed unexpectedly.  WDT will not stop!\n");
0162
0163     clear_bit(0, &mixcomwd_opened);
0164     expect_close = 0;
0165     return 0;
0166 }
0167
0168
0169 static ssize_t mixcomwd_write(struct file *file, const char __user *data,
0170                         size_t len, loff_t *ppos)
0171 {
0172     if (len) {
0173         if (!nowayout) {
0174             size_t i;
0175
0176             /* In case it was set long ago */
0177             expect_close = 0;
0178
0179             for (i = 0; i != len; i++) {
0180                 char c;
0181                 if (get_user(c, data + i))
0182                     return -EFAULT;
0183                 if (c == 'V')
0184                     expect_close = 42;
0185             }
0186         }
0187         mixcomwd_ping();
0188     }
0189     return len;
0190 }
0191
0192 static long mixcomwd_ioctl(struct file *file,
0193                 unsigned int cmd, unsigned long arg)
0194 {
0195     void __user *argp = (void __user *)arg;
0196     int __user *p = argp;
0197     int status;
0198     static const struct watchdog_info ident = {
0199         .options = WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
0200         .firmware_version = 1,
0201         .identity = "MixCOM watchdog",
0202     };
0203
0204     switch (cmd) {
0205     case WDIOC_GETSUPPORT:
0206         if (copy_to_user(argp, &ident, sizeof(ident)))
0207             return -EFAULT;
0208         break;
0209     case WDIOC_GETSTATUS:
0210         status = mixcomwd_opened;
0211         if (!nowayout)
0212             status |= mixcomwd_timer_alive;
0213         return put_user(status, p);
0214     case WDIOC_GETBOOTSTATUS:
0215         return put_user(0, p);
0216     case WDIOC_KEEPALIVE:
0217         mixcomwd_ping();
0218         break;
0219     default:
0220         return -ENOTTY;
0221     }
0222     return 0;
0223 }
0224
0225 static const struct file_operations mixcomwd_fops = {
0226     .owner      = THIS_MODULE,
0227     .llseek     = no_llseek,
0228     .write      = mixcomwd_write,
0229     .unlocked_ioctl = mixcomwd_ioctl,
0230     .compat_ioctl   = compat_ptr_ioctl,
0231     .open       = mixcomwd_open,
0232     .release    = mixcomwd_release,
0233 };
0234
0235 static struct miscdevice mixcomwd_miscdev = {
0236     .minor  = WATCHDOG_MINOR,
0237     .name   = "watchdog",
0238     .fops   = &mixcomwd_fops,
0239 };
0240
0241 static int __init checkcard(int port, int card_id)
0242 {
0243     int id;
0244
0245     if (!request_region(port, 1, "MixCOM watchdog"))
0246         return 0;
0247
0248     id = inb_p(port);
0249     if (card_id == MIXCOM_ID)
0250         id &= 0x3f;
0251
0252     if (id != card_id) {
0253         release_region(port, 1);
0254         return 0;
0255     }
0256     return 1;
0257 }
0258
0259 static int __init mixcomwd_init(void)
0260 {
0261     int i, ret, found = 0;
0262
0263     for (i = 0; !found && mixcomwd_io_info[i].ioport != 0; i++) {
0264         if (checkcard(mixcomwd_io_info[i].ioport,
0265                   mixcomwd_io_info[i].id)) {
0266             found = 1;
0267             watchdog_port = mixcomwd_io_info[i].ioport;
0268         }
0269     }
0270
0271     if (!found) {
0272         pr_err("No card detected, or port not available\n");
0273         return -ENODEV;
0274     }
0275
0276     ret = misc_register(&mixcomwd_miscdev);
0277     if (ret) {
0278         pr_err("cannot register miscdev on minor=%d (err=%d)\n",
0279                WATCHDOG_MINOR, ret);
0280         goto error_misc_register_watchdog;
0281     }
0282
0283     pr_info("MixCOM watchdog driver v%s, watchdog port at 0x%3x\n",
0284         VERSION, watchdog_port);
0285
0286     return 0;
0287
0288 error_misc_register_watchdog:
0289     release_region(watchdog_port, 1);
0290     watchdog_port = 0x0000;
0291     return ret;
0292 }
0293
0294 static void __exit mixcomwd_exit(void)
0295 {
0296     if (!nowayout) {
0297         if (mixcomwd_timer_alive) {
0298             pr_warn("I quit now, hardware will probably reboot!\n");
0299             del_timer_sync(&mixcomwd_timer);
0300             mixcomwd_timer_alive = 0;
0301         }
0302     }
0303     misc_deregister(&mixcomwd_miscdev);
0304     release_region(watchdog_port, 1);
0305 }
0306
0307 module_init(mixcomwd_init);
0308 module_exit(mixcomwd_exit);
0309
0310 MODULE_AUTHOR("Gergely Madarasz <gorgo@itc.hu>");
0311 MODULE_DESCRIPTION("MixCom Watchdog driver");
0312 MODULE_VERSION(VERSION);
0313 MODULE_LICENSE("GPL");