Root/drivers/watchdog/sch311x_wdt.c

1/*
2 * sch311x_wdt.c - Driver for the SCH311x Super-I/O chips
3 * integrated watchdog.
4 *
5 * (c) Copyright 2008 Wim Van Sebroeck <wim@iguana.be>.
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * as published by the Free Software Foundation; either version
10 * 2 of the License, or (at your option) any later version.
11 *
12 * Neither Wim Van Sebroeck nor Iguana vzw. admit liability nor
13 * provide warranty for any of this software. This material is
14 * provided "AS-IS" and at no charge.
15 */
16
17/*
18 * Includes, defines, variables, module parameters, ...
19 */
20
21#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
22
23/* Includes */
24#include <linux/module.h> /* For module specific items */
25#include <linux/moduleparam.h> /* For new moduleparam's */
26#include <linux/types.h> /* For standard types (like size_t) */
27#include <linux/errno.h> /* For the -ENODEV/... values */
28#include <linux/kernel.h> /* For printk/... */
29#include <linux/miscdevice.h> /* For MODULE_ALIAS_MISCDEV
30                            (WATCHDOG_MINOR) */
31#include <linux/watchdog.h> /* For the watchdog specific items */
32#include <linux/init.h> /* For __init/__exit/... */
33#include <linux/fs.h> /* For file operations */
34#include <linux/platform_device.h> /* For platform_driver framework */
35#include <linux/ioport.h> /* For io-port access */
36#include <linux/spinlock.h> /* For spin_lock/spin_unlock/... */
37#include <linux/uaccess.h> /* For copy_to_user/put_user/... */
38#include <linux/io.h> /* For inb/outb/... */
39
40/* Module and version information */
41#define DRV_NAME "sch311x_wdt"
42
43/* Runtime registers */
44#define GP60 0x47
45#define WDT_TIME_OUT 0x65
46#define WDT_VAL 0x66
47#define WDT_CFG 0x67
48#define WDT_CTRL 0x68
49
50/* internal variables */
51static unsigned long sch311x_wdt_is_open;
52static char sch311x_wdt_expect_close;
53static struct platform_device *sch311x_wdt_pdev;
54
55static int sch311x_ioports[] = { 0x2e, 0x4e, 0x162e, 0x164e, 0x00 };
56
57static struct { /* The devices private data */
58    /* the Runtime Register base address */
59    unsigned short runtime_reg;
60    /* The card's boot status */
61    int boot_status;
62    /* the lock for io operations */
63    spinlock_t io_lock;
64} sch311x_wdt_data;
65
66/* Module load parameters */
67static unsigned short force_id;
68module_param(force_id, ushort, 0);
69MODULE_PARM_DESC(force_id, "Override the detected device ID");
70
71#define WATCHDOG_TIMEOUT 60 /* 60 sec default timeout */
72static int timeout = WATCHDOG_TIMEOUT; /* in seconds */
73module_param(timeout, int, 0);
74MODULE_PARM_DESC(timeout,
75    "Watchdog timeout in seconds. 1<= timeout <=15300, default="
76        __MODULE_STRING(WATCHDOG_TIMEOUT) ".");
77
78static bool nowayout = WATCHDOG_NOWAYOUT;
79module_param(nowayout, bool, 0);
80MODULE_PARM_DESC(nowayout,
81    "Watchdog cannot be stopped once started (default="
82        __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
83
84/*
85 * Super-IO functions
86 */
87
88static inline void sch311x_sio_enter(int sio_config_port)
89{
90    outb(0x55, sio_config_port);
91}
92
93static inline void sch311x_sio_exit(int sio_config_port)
94{
95    outb(0xaa, sio_config_port);
96}
97
98static inline int sch311x_sio_inb(int sio_config_port, int reg)
99{
100    outb(reg, sio_config_port);
101    return inb(sio_config_port + 1);
102}
103
104static inline void sch311x_sio_outb(int sio_config_port, int reg, int val)
105{
106    outb(reg, sio_config_port);
107    outb(val, sio_config_port + 1);
108}
109
110/*
111 * Watchdog Operations
112 */
113
114static void sch311x_wdt_set_timeout(int t)
115{
116    unsigned char timeout_unit = 0x80;
117
118    /* When new timeout is bigger then 255 seconds, we will use minutes */
119    if (t > 255) {
120        timeout_unit = 0;
121        t /= 60;
122    }
123
124    /* -- Watchdog Timeout --
125     * Bit 0-6 (Reserved)
126     * Bit 7 WDT Time-out Value Units Select
127     * (0 = Minutes, 1 = Seconds)
128     */
129    outb(timeout_unit, sch311x_wdt_data.runtime_reg + WDT_TIME_OUT);
130
131    /* -- Watchdog Timer Time-out Value --
132     * Bit 0-7 Binary coded units (0=Disabled, 1..255)
133     */
134    outb(t, sch311x_wdt_data.runtime_reg + WDT_VAL);
135}
136
137static void sch311x_wdt_start(void)
138{
139    unsigned char t;
140
141    spin_lock(&sch311x_wdt_data.io_lock);
142
143    /* set watchdog's timeout */
144    sch311x_wdt_set_timeout(timeout);
145    /* enable the watchdog */
146    /* -- General Purpose I/O Bit 6.0 --
147     * Bit 0, In/Out: 0 = Output, 1 = Input
148     * Bit 1, Polarity: 0 = No Invert, 1 = Invert
149     * Bit 2-3, Function select: 00 = GPI/O, 01 = LED1, 11 = WDT,
150     * 10 = Either Edge Triggered Intr.4
151     * Bit 4-6 (Reserved)
152     * Bit 7, Output Type: 0 = Push Pull Bit, 1 = Open Drain
153     */
154    t = inb(sch311x_wdt_data.runtime_reg + GP60);
155    outb((t & ~0x0d) | 0x0c, sch311x_wdt_data.runtime_reg + GP60);
156
157    spin_unlock(&sch311x_wdt_data.io_lock);
158
159}
160
161static void sch311x_wdt_stop(void)
162{
163    unsigned char t;
164
165    spin_lock(&sch311x_wdt_data.io_lock);
166
167    /* stop the watchdog */
168    t = inb(sch311x_wdt_data.runtime_reg + GP60);
169    outb((t & ~0x0d) | 0x01, sch311x_wdt_data.runtime_reg + GP60);
170    /* disable timeout by setting it to 0 */
171    sch311x_wdt_set_timeout(0);
172
173    spin_unlock(&sch311x_wdt_data.io_lock);
174}
175
176static void sch311x_wdt_keepalive(void)
177{
178    spin_lock(&sch311x_wdt_data.io_lock);
179    sch311x_wdt_set_timeout(timeout);
180    spin_unlock(&sch311x_wdt_data.io_lock);
181}
182
183static int sch311x_wdt_set_heartbeat(int t)
184{
185    if (t < 1 || t > (255*60))
186        return -EINVAL;
187
188    /* When new timeout is bigger then 255 seconds,
189     * we will round up to minutes (with a max of 255) */
190    if (t > 255)
191        t = (((t - 1) / 60) + 1) * 60;
192
193    timeout = t;
194    return 0;
195}
196
197static void sch311x_wdt_get_status(int *status)
198{
199    unsigned char new_status;
200
201    *status = 0;
202
203    spin_lock(&sch311x_wdt_data.io_lock);
204
205    /* -- Watchdog timer control --
206     * Bit 0 Status Bit: 0 = Timer counting, 1 = Timeout occurred
207     * Bit 1 Reserved
208     * Bit 2 Force Timeout: 1 = Forces WD timeout event (self-cleaning)
209     * Bit 3 P20 Force Timeout enabled:
210     * 0 = P20 activity does not generate the WD timeout event
211     * 1 = P20 Allows rising edge of P20, from the keyboard
212     * controller, to force the WD timeout event.
213     * Bit 4-7 Reserved
214     */
215    new_status = inb(sch311x_wdt_data.runtime_reg + WDT_CTRL);
216    if (new_status & 0x01)
217        *status |= WDIOF_CARDRESET;
218
219    spin_unlock(&sch311x_wdt_data.io_lock);
220}
221
222/*
223 * /dev/watchdog handling
224 */
225
226static ssize_t sch311x_wdt_write(struct file *file, const char __user *buf,
227                        size_t count, loff_t *ppos)
228{
229    if (count) {
230        if (!nowayout) {
231            size_t i;
232
233            sch311x_wdt_expect_close = 0;
234
235            for (i = 0; i != count; i++) {
236                char c;
237                if (get_user(c, buf + i))
238                    return -EFAULT;
239                if (c == 'V')
240                    sch311x_wdt_expect_close = 42;
241            }
242        }
243        sch311x_wdt_keepalive();
244    }
245    return count;
246}
247
248static long sch311x_wdt_ioctl(struct file *file, unsigned int cmd,
249                            unsigned long arg)
250{
251    int status;
252    int new_timeout;
253    void __user *argp = (void __user *)arg;
254    int __user *p = argp;
255    static const struct watchdog_info ident = {
256        .options = WDIOF_KEEPALIVEPING |
257                      WDIOF_SETTIMEOUT |
258                      WDIOF_MAGICCLOSE,
259        .firmware_version = 1,
260        .identity = DRV_NAME,
261    };
262
263    switch (cmd) {
264    case WDIOC_GETSUPPORT:
265        if (copy_to_user(argp, &ident, sizeof(ident)))
266            return -EFAULT;
267        break;
268
269    case WDIOC_GETSTATUS:
270    {
271        sch311x_wdt_get_status(&status);
272        return put_user(status, p);
273    }
274    case WDIOC_GETBOOTSTATUS:
275        return put_user(sch311x_wdt_data.boot_status, p);
276
277    case WDIOC_SETOPTIONS:
278    {
279        int options, retval = -EINVAL;
280
281        if (get_user(options, p))
282            return -EFAULT;
283        if (options & WDIOS_DISABLECARD) {
284            sch311x_wdt_stop();
285            retval = 0;
286        }
287        if (options & WDIOS_ENABLECARD) {
288            sch311x_wdt_start();
289            retval = 0;
290        }
291        return retval;
292    }
293    case WDIOC_KEEPALIVE:
294        sch311x_wdt_keepalive();
295        break;
296
297    case WDIOC_SETTIMEOUT:
298        if (get_user(new_timeout, p))
299            return -EFAULT;
300        if (sch311x_wdt_set_heartbeat(new_timeout))
301            return -EINVAL;
302        sch311x_wdt_keepalive();
303        /* Fall */
304    case WDIOC_GETTIMEOUT:
305        return put_user(timeout, p);
306    default:
307        return -ENOTTY;
308    }
309    return 0;
310}
311
312static int sch311x_wdt_open(struct inode *inode, struct file *file)
313{
314    if (test_and_set_bit(0, &sch311x_wdt_is_open))
315        return -EBUSY;
316    /*
317     * Activate
318     */
319    sch311x_wdt_start();
320    return nonseekable_open(inode, file);
321}
322
323static int sch311x_wdt_close(struct inode *inode, struct file *file)
324{
325    if (sch311x_wdt_expect_close == 42) {
326        sch311x_wdt_stop();
327    } else {
328        pr_crit("Unexpected close, not stopping watchdog!\n");
329        sch311x_wdt_keepalive();
330    }
331    clear_bit(0, &sch311x_wdt_is_open);
332    sch311x_wdt_expect_close = 0;
333    return 0;
334}
335
336/*
337 * Kernel Interfaces
338 */
339
340static const struct file_operations sch311x_wdt_fops = {
341    .owner = THIS_MODULE,
342    .llseek = no_llseek,
343    .write = sch311x_wdt_write,
344    .unlocked_ioctl = sch311x_wdt_ioctl,
345    .open = sch311x_wdt_open,
346    .release = sch311x_wdt_close,
347};
348
349static struct miscdevice sch311x_wdt_miscdev = {
350    .minor = WATCHDOG_MINOR,
351    .name = "watchdog",
352    .fops = &sch311x_wdt_fops,
353};
354
355/*
356 * Init & exit routines
357 */
358
359static int __devinit sch311x_wdt_probe(struct platform_device *pdev)
360{
361    struct device *dev = &pdev->dev;
362    int err;
363
364    spin_lock_init(&sch311x_wdt_data.io_lock);
365
366    if (!request_region(sch311x_wdt_data.runtime_reg + GP60, 1, DRV_NAME)) {
367        dev_err(dev, "Failed to request region 0x%04x-0x%04x.\n",
368            sch311x_wdt_data.runtime_reg + GP60,
369            sch311x_wdt_data.runtime_reg + GP60);
370        err = -EBUSY;
371        goto exit;
372    }
373
374    if (!request_region(sch311x_wdt_data.runtime_reg + WDT_TIME_OUT, 4,
375                                DRV_NAME)) {
376        dev_err(dev, "Failed to request region 0x%04x-0x%04x.\n",
377            sch311x_wdt_data.runtime_reg + WDT_TIME_OUT,
378            sch311x_wdt_data.runtime_reg + WDT_CTRL);
379        err = -EBUSY;
380        goto exit_release_region;
381    }
382
383    /* Make sure that the watchdog is not running */
384    sch311x_wdt_stop();
385
386    /* Disable keyboard and mouse interaction and interrupt */
387    /* -- Watchdog timer configuration --
388     * Bit 0 Reserved
389     * Bit 1 Keyboard enable: 0* = No Reset, 1 = Reset WDT upon KBD Intr.
390     * Bit 2 Mouse enable: 0* = No Reset, 1 = Reset WDT upon Mouse Intr
391     * Bit 3 Reserved
392     * Bit 4-7 WDT Interrupt Mapping: (0000* = Disabled,
393     * 0001=IRQ1, 0010=(Invalid), 0011=IRQ3 to 1111=IRQ15)
394     */
395    outb(0, sch311x_wdt_data.runtime_reg + WDT_CFG);
396
397    /* Check that the heartbeat value is within it's range ;
398     * if not reset to the default */
399    if (sch311x_wdt_set_heartbeat(timeout)) {
400        sch311x_wdt_set_heartbeat(WATCHDOG_TIMEOUT);
401        dev_info(dev, "timeout value must be 1<=x<=15300, using %d\n",
402            timeout);
403    }
404
405    /* Get status at boot */
406    sch311x_wdt_get_status(&sch311x_wdt_data.boot_status);
407
408    sch311x_wdt_miscdev.parent = dev;
409
410    err = misc_register(&sch311x_wdt_miscdev);
411    if (err != 0) {
412        dev_err(dev, "cannot register miscdev on minor=%d (err=%d)\n",
413                            WATCHDOG_MINOR, err);
414        goto exit_release_region2;
415    }
416
417    dev_info(dev,
418        "SMSC SCH311x WDT initialized. timeout=%d sec (nowayout=%d)\n",
419        timeout, nowayout);
420
421    return 0;
422
423exit_release_region2:
424    release_region(sch311x_wdt_data.runtime_reg + WDT_TIME_OUT, 4);
425exit_release_region:
426    release_region(sch311x_wdt_data.runtime_reg + GP60, 1);
427    sch311x_wdt_data.runtime_reg = 0;
428exit:
429    return err;
430}
431
432static int __devexit sch311x_wdt_remove(struct platform_device *pdev)
433{
434    /* Stop the timer before we leave */
435    if (!nowayout)
436        sch311x_wdt_stop();
437
438    /* Deregister */
439    misc_deregister(&sch311x_wdt_miscdev);
440    release_region(sch311x_wdt_data.runtime_reg + WDT_TIME_OUT, 4);
441    release_region(sch311x_wdt_data.runtime_reg + GP60, 1);
442    sch311x_wdt_data.runtime_reg = 0;
443    return 0;
444}
445
446static void sch311x_wdt_shutdown(struct platform_device *dev)
447{
448    /* Turn the WDT off if we have a soft shutdown */
449    sch311x_wdt_stop();
450}
451
452static struct platform_driver sch311x_wdt_driver = {
453    .probe = sch311x_wdt_probe,
454    .remove = __devexit_p(sch311x_wdt_remove),
455    .shutdown = sch311x_wdt_shutdown,
456    .driver = {
457        .owner = THIS_MODULE,
458        .name = DRV_NAME,
459    },
460};
461
462static int __init sch311x_detect(int sio_config_port, unsigned short *addr)
463{
464    int err = 0, reg;
465    unsigned short base_addr;
466    unsigned char dev_id;
467
468    sch311x_sio_enter(sio_config_port);
469
470    /* Check device ID. We currently know about:
471     * SCH3112 (0x7c), SCH3114 (0x7d), and SCH3116 (0x7f). */
472    reg = force_id ? force_id : sch311x_sio_inb(sio_config_port, 0x20);
473    if (!(reg == 0x7c || reg == 0x7d || reg == 0x7f)) {
474        err = -ENODEV;
475        goto exit;
476    }
477    dev_id = reg == 0x7c ? 2 : reg == 0x7d ? 4 : 6;
478
479    /* Select logical device A (runtime registers) */
480    sch311x_sio_outb(sio_config_port, 0x07, 0x0a);
481
482    /* Check if Logical Device Register is currently active */
483    if ((sch311x_sio_inb(sio_config_port, 0x30) & 0x01) == 0)
484        pr_info("Seems that LDN 0x0a is not active...\n");
485
486    /* Get the base address of the runtime registers */
487    base_addr = (sch311x_sio_inb(sio_config_port, 0x60) << 8) |
488               sch311x_sio_inb(sio_config_port, 0x61);
489    if (!base_addr) {
490        pr_err("Base address not set\n");
491        err = -ENODEV;
492        goto exit;
493    }
494    *addr = base_addr;
495
496    pr_info("Found an SMSC SCH311%d chip at 0x%04x\n", dev_id, base_addr);
497
498exit:
499    sch311x_sio_exit(sio_config_port);
500    return err;
501}
502
503static int __init sch311x_wdt_init(void)
504{
505    int err, i, found = 0;
506    unsigned short addr = 0;
507
508    for (i = 0; !found && sch311x_ioports[i]; i++)
509        if (sch311x_detect(sch311x_ioports[i], &addr) == 0)
510            found++;
511
512    if (!found)
513        return -ENODEV;
514
515    sch311x_wdt_data.runtime_reg = addr;
516
517    err = platform_driver_register(&sch311x_wdt_driver);
518    if (err)
519        return err;
520
521    sch311x_wdt_pdev = platform_device_register_simple(DRV_NAME, addr,
522                                NULL, 0);
523
524    if (IS_ERR(sch311x_wdt_pdev)) {
525        err = PTR_ERR(sch311x_wdt_pdev);
526        goto unreg_platform_driver;
527    }
528
529    return 0;
530
531unreg_platform_driver:
532    platform_driver_unregister(&sch311x_wdt_driver);
533    return err;
534}
535
536static void __exit sch311x_wdt_exit(void)
537{
538    platform_device_unregister(sch311x_wdt_pdev);
539    platform_driver_unregister(&sch311x_wdt_driver);
540}
541
542module_init(sch311x_wdt_init);
543module_exit(sch311x_wdt_exit);
544
545MODULE_AUTHOR("Wim Van Sebroeck <wim@iguana.be>");
546MODULE_DESCRIPTION("SMSC SCH311x WatchDog Timer Driver");
547MODULE_LICENSE("GPL");
548MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
549
550

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