Root/drivers/watchdog/machzwd.c

1/*
2 * MachZ ZF-Logic Watchdog Timer driver for Linux
3 *
4 *
5 * This program is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU General Public License
7 * as published by the Free Software Foundation; either version
8 * 2 of the License, or (at your option) any later version.
9 *
10 * The author does NOT admit liability nor provide warranty for
11 * any of this software. This material is provided "AS-IS" in
12 * the hope that it may be useful for others.
13 *
14 * Author: Fernando Fuganti <fuganti@conectiva.com.br>
15 *
16 * Based on sbc60xxwdt.c by Jakob Oestergaard
17 *
18 *
19 * We have two timers (wd#1, wd#2) driven by a 32 KHz clock with the
20 * following periods:
21 * wd#1 - 2 seconds;
22 * wd#2 - 7.2 ms;
23 * After the expiration of wd#1, it can generate a NMI, SCI, SMI, or
24 * a system RESET and it starts wd#2 that unconditionally will RESET
25 * the system when the counter reaches zero.
26 *
27 * 14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com>
28 * Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT
29 */
30
31#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
32
33#include <linux/module.h>
34#include <linux/moduleparam.h>
35#include <linux/types.h>
36#include <linux/timer.h>
37#include <linux/jiffies.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/io.h>
46#include <linux/uaccess.h>
47
48
49/* ports */
50#define ZF_IOBASE 0x218
51#define INDEX 0x218
52#define DATA_B 0x219
53#define DATA_W 0x21A
54#define DATA_D 0x21A
55
56/* indexes */ /* size */
57#define ZFL_VERSION 0x02 /* 16 */
58#define CONTROL 0x10 /* 16 */
59#define STATUS 0x12 /* 8 */
60#define COUNTER_1 0x0C /* 16 */
61#define COUNTER_2 0x0E /* 8 */
62#define PULSE_LEN 0x0F /* 8 */
63
64/* controls */
65#define ENABLE_WD1 0x0001
66#define ENABLE_WD2 0x0002
67#define RESET_WD1 0x0010
68#define RESET_WD2 0x0020
69#define GEN_SCI 0x0100
70#define GEN_NMI 0x0200
71#define GEN_SMI 0x0400
72#define GEN_RESET 0x0800
73
74
75/* utilities */
76
77#define WD1 0
78#define WD2 1
79
80#define zf_writew(port, data) { outb(port, INDEX); outw(data, DATA_W); }
81#define zf_writeb(port, data) { outb(port, INDEX); outb(data, DATA_B); }
82#define zf_get_ZFL_version() zf_readw(ZFL_VERSION)
83
84
85static unsigned short zf_readw(unsigned char port)
86{
87    outb(port, INDEX);
88    return inw(DATA_W);
89}
90
91
92MODULE_AUTHOR("Fernando Fuganti <fuganti@conectiva.com.br>");
93MODULE_DESCRIPTION("MachZ ZF-Logic Watchdog driver");
94MODULE_LICENSE("GPL");
95MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
96
97static bool nowayout = WATCHDOG_NOWAYOUT;
98module_param(nowayout, bool, 0);
99MODULE_PARM_DESC(nowayout,
100        "Watchdog cannot be stopped once started (default="
101                __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
102
103#define PFX "machzwd"
104
105static const struct watchdog_info zf_info = {
106    .options = WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
107    .firmware_version = 1,
108    .identity = "ZF-Logic watchdog",
109};
110
111
112/*
113 * action refers to action taken when watchdog resets
114 * 0 = GEN_RESET
115 * 1 = GEN_SMI
116 * 2 = GEN_NMI
117 * 3 = GEN_SCI
118 * defaults to GEN_RESET (0)
119 */
120static int action;
121module_param(action, int, 0);
122MODULE_PARM_DESC(action, "after watchdog resets, generate: "
123                "0 = RESET(*) 1 = SMI 2 = NMI 3 = SCI");
124
125static void zf_ping(unsigned long data);
126
127static int zf_action = GEN_RESET;
128static unsigned long zf_is_open;
129static char zf_expect_close;
130static DEFINE_SPINLOCK(zf_port_lock);
131static DEFINE_TIMER(zf_timer, zf_ping, 0, 0);
132static unsigned long next_heartbeat;
133
134
135/* timeout for user land heart beat (10 seconds) */
136#define ZF_USER_TIMEO (HZ*10)
137
138/* timeout for hardware watchdog (~500ms) */
139#define ZF_HW_TIMEO (HZ/2)
140
141/* number of ticks on WD#1 (driven by a 32KHz clock, 2s) */
142#define ZF_CTIMEOUT 0xffff
143
144#ifndef ZF_DEBUG
145#define dprintk(format, args...)
146#else
147#define dprintk(format, args...) \
148    pr_debug(":%s:%d: " format, __func__, __LINE__ , ## args)
149#endif
150
151
152static inline void zf_set_status(unsigned char new)
153{
154    zf_writeb(STATUS, new);
155}
156
157
158/* CONTROL register functions */
159
160static inline unsigned short zf_get_control(void)
161{
162    return zf_readw(CONTROL);
163}
164
165static inline void zf_set_control(unsigned short new)
166{
167    zf_writew(CONTROL, new);
168}
169
170
171/* WD#? counter functions */
172/*
173 * Just set counter value
174 */
175
176static inline void zf_set_timer(unsigned short new, unsigned char n)
177{
178    switch (n) {
179    case WD1:
180        zf_writew(COUNTER_1, new);
181    case WD2:
182        zf_writeb(COUNTER_2, new > 0xff ? 0xff : new);
183    default:
184        return;
185    }
186}
187
188/*
189 * stop hardware timer
190 */
191static void zf_timer_off(void)
192{
193    unsigned int ctrl_reg = 0;
194    unsigned long flags;
195
196    /* stop internal ping */
197    del_timer_sync(&zf_timer);
198
199    spin_lock_irqsave(&zf_port_lock, flags);
200    /* stop watchdog timer */
201    ctrl_reg = zf_get_control();
202    ctrl_reg |= (ENABLE_WD1|ENABLE_WD2); /* disable wd1 and wd2 */
203    ctrl_reg &= ~(ENABLE_WD1|ENABLE_WD2);
204    zf_set_control(ctrl_reg);
205    spin_unlock_irqrestore(&zf_port_lock, flags);
206
207    pr_info("Watchdog timer is now disabled\n");
208}
209
210
211/*
212 * start hardware timer
213 */
214static void zf_timer_on(void)
215{
216    unsigned int ctrl_reg = 0;
217    unsigned long flags;
218
219    spin_lock_irqsave(&zf_port_lock, flags);
220
221    zf_writeb(PULSE_LEN, 0xff);
222
223    zf_set_timer(ZF_CTIMEOUT, WD1);
224
225    /* user land ping */
226    next_heartbeat = jiffies + ZF_USER_TIMEO;
227
228    /* start the timer for internal ping */
229    mod_timer(&zf_timer, jiffies + ZF_HW_TIMEO);
230
231    /* start watchdog timer */
232    ctrl_reg = zf_get_control();
233    ctrl_reg |= (ENABLE_WD1|zf_action);
234    zf_set_control(ctrl_reg);
235    spin_unlock_irqrestore(&zf_port_lock, flags);
236
237    pr_info("Watchdog timer is now enabled\n");
238}
239
240
241static void zf_ping(unsigned long data)
242{
243    unsigned int ctrl_reg = 0;
244    unsigned long flags;
245
246    zf_writeb(COUNTER_2, 0xff);
247
248    if (time_before(jiffies, next_heartbeat)) {
249        dprintk("time_before: %ld\n", next_heartbeat - jiffies);
250        /*
251         * reset event is activated by transition from 0 to 1 on
252         * RESET_WD1 bit and we assume that it is already zero...
253         */
254
255        spin_lock_irqsave(&zf_port_lock, flags);
256        ctrl_reg = zf_get_control();
257        ctrl_reg |= RESET_WD1;
258        zf_set_control(ctrl_reg);
259
260        /* ...and nothing changes until here */
261        ctrl_reg &= ~(RESET_WD1);
262        zf_set_control(ctrl_reg);
263        spin_unlock_irqrestore(&zf_port_lock, flags);
264
265        mod_timer(&zf_timer, jiffies + ZF_HW_TIMEO);
266    } else
267        pr_crit("I will reset your machine\n");
268}
269
270static ssize_t zf_write(struct file *file, const char __user *buf, size_t count,
271                                loff_t *ppos)
272{
273    /* See if we got the magic character */
274    if (count) {
275        /*
276         * no need to check for close confirmation
277         * no way to disable watchdog ;)
278         */
279        if (!nowayout) {
280            size_t ofs;
281            /*
282             * note: just in case someone wrote the magic character
283             * five months ago...
284             */
285            zf_expect_close = 0;
286
287            /* now scan */
288            for (ofs = 0; ofs != count; ofs++) {
289                char c;
290                if (get_user(c, buf + ofs))
291                    return -EFAULT;
292                if (c == 'V') {
293                    zf_expect_close = 42;
294                    dprintk("zf_expect_close = 42\n");
295                }
296            }
297        }
298
299        /*
300         * Well, anyhow someone wrote to us,
301         * we should return that favour
302         */
303        next_heartbeat = jiffies + ZF_USER_TIMEO;
304        dprintk("user ping at %ld\n", jiffies);
305    }
306    return count;
307}
308
309static long zf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
310{
311    void __user *argp = (void __user *)arg;
312    int __user *p = argp;
313    switch (cmd) {
314    case WDIOC_GETSUPPORT:
315        if (copy_to_user(argp, &zf_info, sizeof(zf_info)))
316            return -EFAULT;
317        break;
318    case WDIOC_GETSTATUS:
319    case WDIOC_GETBOOTSTATUS:
320        return put_user(0, p);
321    case WDIOC_KEEPALIVE:
322        zf_ping(0);
323        break;
324    default:
325        return -ENOTTY;
326    }
327    return 0;
328}
329
330static int zf_open(struct inode *inode, struct file *file)
331{
332    if (test_and_set_bit(0, &zf_is_open))
333        return -EBUSY;
334    if (nowayout)
335        __module_get(THIS_MODULE);
336    zf_timer_on();
337    return nonseekable_open(inode, file);
338}
339
340static int zf_close(struct inode *inode, struct file *file)
341{
342    if (zf_expect_close == 42)
343        zf_timer_off();
344    else {
345        del_timer(&zf_timer);
346        pr_err("device file closed unexpectedly. Will not stop the WDT!\n");
347    }
348    clear_bit(0, &zf_is_open);
349    zf_expect_close = 0;
350    return 0;
351}
352
353/*
354 * Notifier for system down
355 */
356
357static int zf_notify_sys(struct notifier_block *this, unsigned long code,
358                                void *unused)
359{
360    if (code == SYS_DOWN || code == SYS_HALT)
361        zf_timer_off();
362    return NOTIFY_DONE;
363}
364
365static const struct file_operations zf_fops = {
366    .owner = THIS_MODULE,
367    .llseek = no_llseek,
368    .write = zf_write,
369    .unlocked_ioctl = zf_ioctl,
370    .open = zf_open,
371    .release = zf_close,
372};
373
374static struct miscdevice zf_miscdev = {
375    .minor = WATCHDOG_MINOR,
376    .name = "watchdog",
377    .fops = &zf_fops,
378};
379
380
381/*
382 * The device needs to learn about soft shutdowns in order to
383 * turn the timebomb registers off.
384 */
385static struct notifier_block zf_notifier = {
386    .notifier_call = zf_notify_sys,
387};
388
389static void __init zf_show_action(int act)
390{
391    static const char * const str[] = { "RESET", "SMI", "NMI", "SCI" };
392
393    pr_info("Watchdog using action = %s\n", str[act]);
394}
395
396static int __init zf_init(void)
397{
398    int ret;
399
400    pr_info("MachZ ZF-Logic Watchdog driver initializing\n");
401
402    ret = zf_get_ZFL_version();
403    if (!ret || ret == 0xffff) {
404        pr_warn("no ZF-Logic found\n");
405        return -ENODEV;
406    }
407
408    if (action <= 3 && action >= 0)
409        zf_action = zf_action >> action;
410    else
411        action = 0;
412
413    zf_show_action(action);
414
415    if (!request_region(ZF_IOBASE, 3, "MachZ ZFL WDT")) {
416        pr_err("cannot reserve I/O ports at %d\n", ZF_IOBASE);
417        ret = -EBUSY;
418        goto no_region;
419    }
420
421    ret = register_reboot_notifier(&zf_notifier);
422    if (ret) {
423        pr_err("can't register reboot notifier (err=%d)\n", ret);
424        goto no_reboot;
425    }
426
427    ret = misc_register(&zf_miscdev);
428    if (ret) {
429        pr_err("can't misc_register on minor=%d\n", WATCHDOG_MINOR);
430        goto no_misc;
431    }
432
433    zf_set_status(0);
434    zf_set_control(0);
435
436    return 0;
437
438no_misc:
439    unregister_reboot_notifier(&zf_notifier);
440no_reboot:
441    release_region(ZF_IOBASE, 3);
442no_region:
443    return ret;
444}
445
446
447static void __exit zf_exit(void)
448{
449    zf_timer_off();
450
451    misc_deregister(&zf_miscdev);
452    unregister_reboot_notifier(&zf_notifier);
453    release_region(ZF_IOBASE, 3);
454}
455
456module_init(zf_init);
457module_exit(zf_exit);
458

Archive Download this file

Branches:
ben-wpan
ben-wpan-stefan
javiroman/ks7010
jz-2.6.34
jz-2.6.34-rc5
jz-2.6.34-rc6
jz-2.6.34-rc7
jz-2.6.35
jz-2.6.36
jz-2.6.37
jz-2.6.38
jz-2.6.39
jz-3.0
jz-3.1
jz-3.11
jz-3.12
jz-3.13
jz-3.15
jz-3.16
jz-3.18-dt
jz-3.2
jz-3.3
jz-3.4
jz-3.5
jz-3.6
jz-3.6-rc2-pwm
jz-3.9
jz-3.9-clk
jz-3.9-rc8
jz47xx
jz47xx-2.6.38
master

Tags:
od-2011-09-04
od-2011-09-18
v2.6.34-rc5
v2.6.34-rc6
v2.6.34-rc7
v3.9



interactive