Root/drivers/watchdog/w83697ug_wdt.c

1/*
2 * w83697ug/uf WDT driver
3 *
4 * (c) Copyright 2008 Flemming Fransen <ff@nrvissing.net>
5 * reused original code to support w83697ug/uf.
6 *
7 * Based on w83627hf_wdt.c which is based on advantechwdt.c
8 * which is based on wdt.c.
9 * Original copyright messages:
10 *
11 * (c) Copyright 2007 Vlad Drukker <vlad@storewiz.com>
12 * added support for W83627THF.
13 *
14 * (c) Copyright 2003 Pádraig Brady <P@draigBrady.com>
15 *
16 * (c) Copyright 2000-2001 Marek Michalkiewicz <marekm@linux.org.pl>
17 *
18 * (c) Copyright 1996 Alan Cox <alan@redhat.com>, All Rights Reserved.
19 * http://www.redhat.com
20 *
21 * This program is free software; you can redistribute it and/or
22 * modify it under the terms of the GNU General Public License
23 * as published by the Free Software Foundation; either version
24 * 2 of the License, or (at your option) any later version.
25 *
26 * Neither Alan Cox nor CymruNet Ltd. admit liability nor provide
27 * warranty for any of this software. This material is provided
28 * "AS-IS" and at no charge.
29 *
30 * (c) Copyright 1995 Alan Cox <alan@redhat.com>
31 */
32
33#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
34
35#include <linux/module.h>
36#include <linux/moduleparam.h>
37#include <linux/types.h>
38#include <linux/miscdevice.h>
39#include <linux/watchdog.h>
40#include <linux/fs.h>
41#include <linux/ioport.h>
42#include <linux/notifier.h>
43#include <linux/reboot.h>
44#include <linux/init.h>
45#include <linux/spinlock.h>
46#include <linux/io.h>
47#include <linux/uaccess.h>
48
49
50#define WATCHDOG_NAME "w83697ug/uf WDT"
51#define WATCHDOG_TIMEOUT 60 /* 60 sec default timeout */
52
53static unsigned long wdt_is_open;
54static char expect_close;
55static DEFINE_SPINLOCK(io_lock);
56
57static int wdt_io = 0x2e;
58module_param(wdt_io, int, 0);
59MODULE_PARM_DESC(wdt_io, "w83697ug/uf WDT io port (default 0x2e)");
60
61static int timeout = WATCHDOG_TIMEOUT; /* in seconds */
62module_param(timeout, int, 0);
63MODULE_PARM_DESC(timeout,
64    "Watchdog timeout in seconds. 1<= timeout <=255 (default="
65                __MODULE_STRING(WATCHDOG_TIMEOUT) ")");
66
67static bool nowayout = WATCHDOG_NOWAYOUT;
68module_param(nowayout, bool, 0);
69MODULE_PARM_DESC(nowayout,
70    "Watchdog cannot be stopped once started (default="
71                __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
72
73/*
74 * Kernel methods.
75 */
76
77#define WDT_EFER (wdt_io+0) /* Extended Function Enable Registers */
78#define WDT_EFIR (wdt_io+0) /* Extended Function Index Register
79                            (same as EFER) */
80#define WDT_EFDR (WDT_EFIR+1) /* Extended Function Data Register */
81
82static int w83697ug_select_wd_register(void)
83{
84    unsigned char c;
85    unsigned char version;
86
87    outb_p(0x87, WDT_EFER); /* Enter extended function mode */
88    outb_p(0x87, WDT_EFER); /* Again according to manual */
89
90    outb(0x20, WDT_EFER); /* check chip version */
91    version = inb(WDT_EFDR);
92
93    if (version == 0x68) { /* W83697UG */
94        pr_info("Watchdog chip version 0x%02x = W83697UG/UF found at 0x%04x\n",
95            version, wdt_io);
96
97        outb_p(0x2b, WDT_EFER);
98        c = inb_p(WDT_EFDR); /* select WDT0 */
99        c &= ~0x04;
100        outb_p(0x2b, WDT_EFER);
101        outb_p(c, WDT_EFDR); /* set pin118 to WDT0 */
102
103    } else {
104        pr_err("No W83697UG/UF could be found\n");
105        return -ENODEV;
106    }
107
108    outb_p(0x07, WDT_EFER); /* point to logical device number reg */
109    outb_p(0x08, WDT_EFDR); /* select logical device 8 (GPIO2) */
110    outb_p(0x30, WDT_EFER); /* select CR30 */
111    c = inb_p(WDT_EFDR);
112    outb_p(c | 0x01, WDT_EFDR); /* set bit 0 to activate GPIO2 */
113
114    return 0;
115}
116
117static void w83697ug_unselect_wd_register(void)
118{
119    outb_p(0xAA, WDT_EFER); /* Leave extended function mode */
120}
121
122static int w83697ug_init(void)
123{
124    int ret;
125    unsigned char t;
126
127    ret = w83697ug_select_wd_register();
128    if (ret != 0)
129        return ret;
130
131    outb_p(0xF6, WDT_EFER); /* Select CRF6 */
132    t = inb_p(WDT_EFDR); /* read CRF6 */
133    if (t != 0) {
134        pr_info("Watchdog already running. Resetting timeout to %d sec\n",
135            timeout);
136        outb_p(timeout, WDT_EFDR); /* Write back to CRF6 */
137    }
138    outb_p(0xF5, WDT_EFER); /* Select CRF5 */
139    t = inb_p(WDT_EFDR); /* read CRF5 */
140    t &= ~0x0C; /* set second mode &
141                    disable keyboard turning off watchdog */
142    outb_p(t, WDT_EFDR); /* Write back to CRF5 */
143
144    w83697ug_unselect_wd_register();
145    return 0;
146}
147
148static void wdt_ctrl(int timeout)
149{
150    spin_lock(&io_lock);
151
152    if (w83697ug_select_wd_register() < 0) {
153        spin_unlock(&io_lock);
154        return;
155    }
156
157    outb_p(0xF4, WDT_EFER); /* Select CRF4 */
158    outb_p(timeout, WDT_EFDR); /* Write Timeout counter to CRF4 */
159
160    w83697ug_unselect_wd_register();
161
162    spin_unlock(&io_lock);
163}
164
165static int wdt_ping(void)
166{
167    wdt_ctrl(timeout);
168    return 0;
169}
170
171static int wdt_disable(void)
172{
173    wdt_ctrl(0);
174    return 0;
175}
176
177static int wdt_set_heartbeat(int t)
178{
179    if (t < 1 || t > 255)
180        return -EINVAL;
181
182    timeout = t;
183    return 0;
184}
185
186static ssize_t wdt_write(struct file *file, const char __user *buf,
187                        size_t count, loff_t *ppos)
188{
189    if (count) {
190        if (!nowayout) {
191            size_t i;
192
193            expect_close = 0;
194
195            for (i = 0; i != count; i++) {
196                char c;
197                if (get_user(c, buf + i))
198                    return -EFAULT;
199                if (c == 'V')
200                    expect_close = 42;
201            }
202        }
203        wdt_ping();
204    }
205    return count;
206}
207
208static long wdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
209{
210    void __user *argp = (void __user *)arg;
211    int __user *p = argp;
212    int new_timeout;
213    static const struct watchdog_info ident = {
214        .options = WDIOF_KEEPALIVEPING |
215                    WDIOF_SETTIMEOUT |
216                    WDIOF_MAGICCLOSE,
217        .firmware_version = 1,
218        .identity = "W83697UG WDT",
219    };
220
221    switch (cmd) {
222    case WDIOC_GETSUPPORT:
223        if (copy_to_user(argp, &ident, sizeof(ident)))
224            return -EFAULT;
225        break;
226
227    case WDIOC_GETSTATUS:
228    case WDIOC_GETBOOTSTATUS:
229        return put_user(0, p);
230
231    case WDIOC_SETOPTIONS:
232    {
233        int options, retval = -EINVAL;
234
235        if (get_user(options, p))
236            return -EFAULT;
237
238        if (options & WDIOS_DISABLECARD) {
239            wdt_disable();
240            retval = 0;
241        }
242
243        if (options & WDIOS_ENABLECARD) {
244            wdt_ping();
245            retval = 0;
246        }
247
248        return retval;
249    }
250
251    case WDIOC_KEEPALIVE:
252        wdt_ping();
253        break;
254
255    case WDIOC_SETTIMEOUT:
256        if (get_user(new_timeout, p))
257            return -EFAULT;
258        if (wdt_set_heartbeat(new_timeout))
259            return -EINVAL;
260        wdt_ping();
261        /* Fall */
262
263    case WDIOC_GETTIMEOUT:
264        return put_user(timeout, p);
265
266    default:
267        return -ENOTTY;
268    }
269    return 0;
270}
271
272static int wdt_open(struct inode *inode, struct file *file)
273{
274    if (test_and_set_bit(0, &wdt_is_open))
275        return -EBUSY;
276    /*
277     * Activate
278     */
279
280    wdt_ping();
281    return nonseekable_open(inode, file);
282}
283
284static int wdt_close(struct inode *inode, struct file *file)
285{
286    if (expect_close == 42)
287        wdt_disable();
288    else {
289        pr_crit("Unexpected close, not stopping watchdog!\n");
290        wdt_ping();
291    }
292    expect_close = 0;
293    clear_bit(0, &wdt_is_open);
294    return 0;
295}
296
297/*
298 * Notifier for system down
299 */
300
301static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
302    void *unused)
303{
304    if (code == SYS_DOWN || code == SYS_HALT)
305        wdt_disable(); /* Turn the WDT off */
306
307    return NOTIFY_DONE;
308}
309
310/*
311 * Kernel Interfaces
312 */
313
314static const struct file_operations wdt_fops = {
315    .owner = THIS_MODULE,
316    .llseek = no_llseek,
317    .write = wdt_write,
318    .unlocked_ioctl = wdt_ioctl,
319    .open = wdt_open,
320    .release = wdt_close,
321};
322
323static struct miscdevice wdt_miscdev = {
324    .minor = WATCHDOG_MINOR,
325    .name = "watchdog",
326    .fops = &wdt_fops,
327};
328
329/*
330 * The WDT needs to learn about soft shutdowns in order to
331 * turn the timebomb registers off.
332 */
333
334static struct notifier_block wdt_notifier = {
335    .notifier_call = wdt_notify_sys,
336};
337
338static int __init wdt_init(void)
339{
340    int ret;
341
342    pr_info("WDT driver for the Winbond(TM) W83697UG/UF Super I/O chip initialising\n");
343
344    if (wdt_set_heartbeat(timeout)) {
345        wdt_set_heartbeat(WATCHDOG_TIMEOUT);
346        pr_info("timeout value must be 1<=timeout<=255, using %d\n",
347            WATCHDOG_TIMEOUT);
348    }
349
350    if (!request_region(wdt_io, 1, WATCHDOG_NAME)) {
351        pr_err("I/O address 0x%04x already in use\n", wdt_io);
352        ret = -EIO;
353        goto out;
354    }
355
356    ret = w83697ug_init();
357    if (ret != 0)
358        goto unreg_regions;
359
360    ret = register_reboot_notifier(&wdt_notifier);
361    if (ret != 0) {
362        pr_err("cannot register reboot notifier (err=%d)\n", ret);
363        goto unreg_regions;
364    }
365
366    ret = misc_register(&wdt_miscdev);
367    if (ret != 0) {
368        pr_err("cannot register miscdev on minor=%d (err=%d)\n",
369               WATCHDOG_MINOR, ret);
370        goto unreg_reboot;
371    }
372
373    pr_info("initialized. timeout=%d sec (nowayout=%d)\n",
374        timeout, nowayout);
375
376out:
377    return ret;
378unreg_reboot:
379    unregister_reboot_notifier(&wdt_notifier);
380unreg_regions:
381    release_region(wdt_io, 1);
382    goto out;
383}
384
385static void __exit wdt_exit(void)
386{
387    misc_deregister(&wdt_miscdev);
388    unregister_reboot_notifier(&wdt_notifier);
389    release_region(wdt_io, 1);
390}
391
392module_init(wdt_init);
393module_exit(wdt_exit);
394
395MODULE_LICENSE("GPL");
396MODULE_AUTHOR("Flemming Frandsen <ff@nrvissing.net>");
397MODULE_DESCRIPTION("w83697ug/uf WDT driver");
398MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
399

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