Root/drivers/watchdog/w83627hf_wdt.c

1/*
2 * w83627hf/thf WDT driver
3 *
4 * (c) Copyright 2007 Vlad Drukker <vlad@storewiz.com>
5 * added support for W83627THF.
6 *
7 * (c) Copyright 2003,2007 Pádraig Brady <P@draigBrady.com>
8 *
9 * Based on advantechwdt.c which is based on wdt.c.
10 * Original copyright messages:
11 *
12 * (c) Copyright 2000-2001 Marek Michalkiewicz <marekm@linux.org.pl>
13 *
14 * (c) Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk>,
15 * All Rights Reserved.
16 *
17 * This program is free software; you can redistribute it and/or
18 * modify it under the terms of the GNU General Public License
19 * as published by the Free Software Foundation; either version
20 * 2 of the License, or (at your option) any later version.
21 *
22 * Neither Alan Cox nor CymruNet Ltd. admit liability nor provide
23 * warranty for any of this software. This material is provided
24 * "AS-IS" and at no charge.
25 *
26 * (c) Copyright 1995 Alan Cox <alan@lxorguk.ukuu.org.uk>
27 */
28
29#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
30
31#include <linux/module.h>
32#include <linux/moduleparam.h>
33#include <linux/types.h>
34#include <linux/miscdevice.h>
35#include <linux/watchdog.h>
36#include <linux/fs.h>
37#include <linux/ioport.h>
38#include <linux/notifier.h>
39#include <linux/reboot.h>
40#include <linux/init.h>
41#include <linux/spinlock.h>
42#include <linux/io.h>
43#include <linux/uaccess.h>
44
45
46#define WATCHDOG_NAME "w83627hf/thf/hg/dhg WDT"
47#define WATCHDOG_TIMEOUT 60 /* 60 sec default timeout */
48
49static unsigned long wdt_is_open;
50static char expect_close;
51static DEFINE_SPINLOCK(io_lock);
52
53/* You must set this - there is no sane way to probe for this board. */
54static int wdt_io = 0x2E;
55module_param(wdt_io, int, 0);
56MODULE_PARM_DESC(wdt_io, "w83627hf/thf WDT io port (default 0x2E)");
57
58static int timeout = WATCHDOG_TIMEOUT; /* in seconds */
59module_param(timeout, int, 0);
60MODULE_PARM_DESC(timeout,
61        "Watchdog timeout in seconds. 1 <= timeout <= 255, default="
62                __MODULE_STRING(WATCHDOG_TIMEOUT) ".");
63
64static bool nowayout = WATCHDOG_NOWAYOUT;
65module_param(nowayout, bool, 0);
66MODULE_PARM_DESC(nowayout,
67        "Watchdog cannot be stopped once started (default="
68                __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
69
70/*
71 * Kernel methods.
72 */
73
74#define WDT_EFER (wdt_io+0) /* Extended Function Enable Registers */
75#define WDT_EFIR (wdt_io+0) /* Extended Function Index Register
76                            (same as EFER) */
77#define WDT_EFDR (WDT_EFIR+1) /* Extended Function Data Register */
78
79static void w83627hf_select_wd_register(void)
80{
81    unsigned char c;
82    outb_p(0x87, WDT_EFER); /* Enter extended function mode */
83    outb_p(0x87, WDT_EFER); /* Again according to manual */
84
85    outb(0x20, WDT_EFER); /* check chip version */
86    c = inb(WDT_EFDR);
87    if (c == 0x82) { /* W83627THF */
88        outb_p(0x2b, WDT_EFER); /* select GPIO3 */
89        c = ((inb_p(WDT_EFDR) & 0xf7) | 0x04); /* select WDT0 */
90        outb_p(0x2b, WDT_EFER);
91        outb_p(c, WDT_EFDR); /* set GPIO3 to WDT0 */
92    } else if (c == 0x88 || c == 0xa0) { /* W83627EHF / W83627DHG */
93        outb_p(0x2d, WDT_EFER); /* select GPIO5 */
94        c = inb_p(WDT_EFDR) & ~0x01; /* PIN77 -> WDT0# */
95        outb_p(0x2d, WDT_EFER);
96        outb_p(c, WDT_EFDR); /* set GPIO5 to WDT0 */
97    }
98
99    outb_p(0x07, WDT_EFER); /* point to logical device number reg */
100    outb_p(0x08, WDT_EFDR); /* select logical device 8 (GPIO2) */
101    outb_p(0x30, WDT_EFER); /* select CR30 */
102    outb_p(0x01, WDT_EFDR); /* set bit 0 to activate GPIO2 */
103}
104
105static void w83627hf_unselect_wd_register(void)
106{
107    outb_p(0xAA, WDT_EFER); /* Leave extended function mode */
108}
109
110/* tyan motherboards seem to set F5 to 0x4C ?
111 * So explicitly init to appropriate value. */
112
113static void w83627hf_init(void)
114{
115    unsigned char t;
116
117    w83627hf_select_wd_register();
118
119    outb_p(0xF6, WDT_EFER); /* Select CRF6 */
120    t = inb_p(WDT_EFDR); /* read CRF6 */
121    if (t != 0) {
122        pr_info("Watchdog already running. Resetting timeout to %d sec\n",
123            timeout);
124        outb_p(timeout, WDT_EFDR); /* Write back to CRF6 */
125    }
126
127    outb_p(0xF5, WDT_EFER); /* Select CRF5 */
128    t = inb_p(WDT_EFDR); /* read CRF5 */
129    t &= ~0x0C; /* set second mode & disable keyboard
130                    turning off watchdog */
131    t |= 0x02; /* enable the WDTO# output low pulse
132                    to the KBRST# pin (PIN60) */
133    outb_p(t, WDT_EFDR); /* Write back to CRF5 */
134
135    outb_p(0xF7, WDT_EFER); /* Select CRF7 */
136    t = inb_p(WDT_EFDR); /* read CRF7 */
137    t &= ~0xC0; /* disable keyboard & mouse turning off
138                    watchdog */
139    outb_p(t, WDT_EFDR); /* Write back to CRF7 */
140
141    w83627hf_unselect_wd_register();
142}
143
144static void wdt_set_time(int timeout)
145{
146    spin_lock(&io_lock);
147
148    w83627hf_select_wd_register();
149
150    outb_p(0xF6, WDT_EFER); /* Select CRF6 */
151    outb_p(timeout, WDT_EFDR); /* Write Timeout counter to CRF6 */
152
153    w83627hf_unselect_wd_register();
154
155    spin_unlock(&io_lock);
156}
157
158static int wdt_ping(void)
159{
160    wdt_set_time(timeout);
161    return 0;
162}
163
164static int wdt_disable(void)
165{
166    wdt_set_time(0);
167    return 0;
168}
169
170static int wdt_set_heartbeat(int t)
171{
172    if (t < 1 || t > 255)
173        return -EINVAL;
174    timeout = t;
175    return 0;
176}
177
178static int wdt_get_time(void)
179{
180    int timeleft;
181
182    spin_lock(&io_lock);
183
184    w83627hf_select_wd_register();
185
186    outb_p(0xF6, WDT_EFER); /* Select CRF6 */
187    timeleft = inb_p(WDT_EFDR); /* Read Timeout counter to CRF6 */
188
189    w83627hf_unselect_wd_register();
190
191    spin_unlock(&io_lock);
192
193    return timeleft;
194}
195
196static ssize_t wdt_write(struct file *file, const char __user *buf,
197                        size_t count, loff_t *ppos)
198{
199    if (count) {
200        if (!nowayout) {
201            size_t i;
202
203            expect_close = 0;
204
205            for (i = 0; i != count; i++) {
206                char c;
207                if (get_user(c, buf + i))
208                    return -EFAULT;
209                if (c == 'V')
210                    expect_close = 42;
211            }
212        }
213        wdt_ping();
214    }
215    return count;
216}
217
218static long wdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
219{
220    void __user *argp = (void __user *)arg;
221    int __user *p = argp;
222    int timeval;
223    static const struct watchdog_info ident = {
224        .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT |
225                            WDIOF_MAGICCLOSE,
226        .firmware_version = 1,
227        .identity = "W83627HF WDT",
228    };
229
230    switch (cmd) {
231    case WDIOC_GETSUPPORT:
232        if (copy_to_user(argp, &ident, sizeof(ident)))
233            return -EFAULT;
234        break;
235    case WDIOC_GETSTATUS:
236    case WDIOC_GETBOOTSTATUS:
237        return put_user(0, p);
238    case WDIOC_SETOPTIONS:
239    {
240        int options, retval = -EINVAL;
241
242        if (get_user(options, p))
243            return -EFAULT;
244        if (options & WDIOS_DISABLECARD) {
245            wdt_disable();
246            retval = 0;
247        }
248        if (options & WDIOS_ENABLECARD) {
249            wdt_ping();
250            retval = 0;
251        }
252        return retval;
253    }
254    case WDIOC_KEEPALIVE:
255        wdt_ping();
256        break;
257    case WDIOC_SETTIMEOUT:
258        if (get_user(timeval, p))
259            return -EFAULT;
260        if (wdt_set_heartbeat(timeval))
261            return -EINVAL;
262        wdt_ping();
263        /* Fall */
264    case WDIOC_GETTIMEOUT:
265        return put_user(timeout, p);
266    case WDIOC_GETTIMELEFT:
267        timeval = wdt_get_time();
268        return put_user(timeval, p);
269    default:
270        return -ENOTTY;
271    }
272    return 0;
273}
274
275static int wdt_open(struct inode *inode, struct file *file)
276{
277    if (test_and_set_bit(0, &wdt_is_open))
278        return -EBUSY;
279    /*
280     * Activate
281     */
282
283    wdt_ping();
284    return nonseekable_open(inode, file);
285}
286
287static int wdt_close(struct inode *inode, struct file *file)
288{
289    if (expect_close == 42)
290        wdt_disable();
291    else {
292        pr_crit("Unexpected close, not stopping watchdog!\n");
293        wdt_ping();
294    }
295    expect_close = 0;
296    clear_bit(0, &wdt_is_open);
297    return 0;
298}
299
300/*
301 * Notifier for system down
302 */
303
304static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
305    void *unused)
306{
307    if (code == SYS_DOWN || code == SYS_HALT)
308        wdt_disable(); /* Turn the WDT off */
309
310    return NOTIFY_DONE;
311}
312
313/*
314 * Kernel Interfaces
315 */
316
317static const struct file_operations wdt_fops = {
318    .owner = THIS_MODULE,
319    .llseek = no_llseek,
320    .write = wdt_write,
321    .unlocked_ioctl = wdt_ioctl,
322    .open = wdt_open,
323    .release = wdt_close,
324};
325
326static struct miscdevice wdt_miscdev = {
327    .minor = WATCHDOG_MINOR,
328    .name = "watchdog",
329    .fops = &wdt_fops,
330};
331
332/*
333 * The WDT needs to learn about soft shutdowns in order to
334 * turn the timebomb registers off.
335 */
336
337static struct notifier_block wdt_notifier = {
338    .notifier_call = wdt_notify_sys,
339};
340
341static int __init wdt_init(void)
342{
343    int ret;
344
345    pr_info("WDT driver for the Winbond(TM) W83627HF/THF/HG/DHG Super I/O chip initialising\n");
346
347    if (wdt_set_heartbeat(timeout)) {
348        wdt_set_heartbeat(WATCHDOG_TIMEOUT);
349        pr_info("timeout value must be 1 <= timeout <= 255, using %d\n",
350            WATCHDOG_TIMEOUT);
351    }
352
353    if (!request_region(wdt_io, 1, WATCHDOG_NAME)) {
354        pr_err("I/O address 0x%04x already in use\n", wdt_io);
355        ret = -EIO;
356        goto out;
357    }
358
359    w83627hf_init();
360
361    ret = register_reboot_notifier(&wdt_notifier);
362    if (ret != 0) {
363        pr_err("cannot register reboot notifier (err=%d)\n", ret);
364        goto unreg_regions;
365    }
366
367    ret = misc_register(&wdt_miscdev);
368    if (ret != 0) {
369        pr_err("cannot register miscdev on minor=%d (err=%d)\n",
370               WATCHDOG_MINOR, ret);
371        goto unreg_reboot;
372    }
373
374    pr_info("initialized. timeout=%d sec (nowayout=%d)\n",
375        timeout, nowayout);
376
377out:
378    return ret;
379unreg_reboot:
380    unregister_reboot_notifier(&wdt_notifier);
381unreg_regions:
382    release_region(wdt_io, 1);
383    goto out;
384}
385
386static void __exit wdt_exit(void)
387{
388    misc_deregister(&wdt_miscdev);
389    unregister_reboot_notifier(&wdt_notifier);
390    release_region(wdt_io, 1);
391}
392
393module_init(wdt_init);
394module_exit(wdt_exit);
395
396MODULE_LICENSE("GPL");
397MODULE_AUTHOR("Pádraig Brady <P@draigBrady.com>");
398MODULE_DESCRIPTION("w83627hf/thf WDT driver");
399MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
400

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