Root/drivers/watchdog/nv_tco.c

1/*
2 * nv_tco 0.01: TCO timer driver for NV chipsets
3 *
4 * (c) Copyright 2005 Google Inc., All Rights Reserved.
5 *
6 * Based off i8xx_tco.c:
7 * (c) Copyright 2000 kernel concepts <nils@kernelconcepts.de>, All Rights
8 * Reserved.
9 * http://www.kernelconcepts.de
10 *
11 * This program is free software; you can redistribute it and/or
12 * modify it under the terms of the GNU General Public License
13 * as published by the Free Software Foundation; either version
14 * 2 of the License, or (at your option) any later version.
15 *
16 * TCO timer driver for NV chipsets
17 * based on softdog.c by Alan Cox <alan@redhat.com>
18 */
19
20/*
21 * Includes, defines, variables, module parameters, ...
22 */
23
24#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
25
26#include <linux/module.h>
27#include <linux/moduleparam.h>
28#include <linux/types.h>
29#include <linux/miscdevice.h>
30#include <linux/watchdog.h>
31#include <linux/init.h>
32#include <linux/fs.h>
33#include <linux/pci.h>
34#include <linux/ioport.h>
35#include <linux/jiffies.h>
36#include <linux/platform_device.h>
37#include <linux/uaccess.h>
38#include <linux/io.h>
39
40#include "nv_tco.h"
41
42/* Module and version information */
43#define TCO_VERSION "0.01"
44#define TCO_MODULE_NAME "NV_TCO"
45#define TCO_DRIVER_NAME TCO_MODULE_NAME ", v" TCO_VERSION
46
47/* internal variables */
48static unsigned int tcobase;
49static DEFINE_SPINLOCK(tco_lock); /* Guards the hardware */
50static unsigned long timer_alive;
51static char tco_expect_close;
52static struct pci_dev *tco_pci;
53
54/* the watchdog platform device */
55static struct platform_device *nv_tco_platform_device;
56
57/* module parameters */
58#define WATCHDOG_HEARTBEAT 30 /* 30 sec default heartbeat (2<heartbeat<39) */
59static int heartbeat = WATCHDOG_HEARTBEAT; /* in seconds */
60module_param(heartbeat, int, 0);
61MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds. (2<heartbeat<39, "
62                "default=" __MODULE_STRING(WATCHDOG_HEARTBEAT) ")");
63
64static bool nowayout = WATCHDOG_NOWAYOUT;
65module_param(nowayout, bool, 0);
66MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started"
67        " (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
68
69/*
70 * Some TCO specific functions
71 */
72static inline unsigned char seconds_to_ticks(int seconds)
73{
74    /* the internal timer is stored as ticks which decrement
75     * every 0.6 seconds */
76    return (seconds * 10) / 6;
77}
78
79static void tco_timer_start(void)
80{
81    u32 val;
82    unsigned long flags;
83
84    spin_lock_irqsave(&tco_lock, flags);
85    val = inl(TCO_CNT(tcobase));
86    val &= ~TCO_CNT_TCOHALT;
87    outl(val, TCO_CNT(tcobase));
88    spin_unlock_irqrestore(&tco_lock, flags);
89}
90
91static void tco_timer_stop(void)
92{
93    u32 val;
94    unsigned long flags;
95
96    spin_lock_irqsave(&tco_lock, flags);
97    val = inl(TCO_CNT(tcobase));
98    val |= TCO_CNT_TCOHALT;
99    outl(val, TCO_CNT(tcobase));
100    spin_unlock_irqrestore(&tco_lock, flags);
101}
102
103static void tco_timer_keepalive(void)
104{
105    unsigned long flags;
106
107    spin_lock_irqsave(&tco_lock, flags);
108    outb(0x01, TCO_RLD(tcobase));
109    spin_unlock_irqrestore(&tco_lock, flags);
110}
111
112static int tco_timer_set_heartbeat(int t)
113{
114    int ret = 0;
115    unsigned char tmrval;
116    unsigned long flags;
117    u8 val;
118
119    /*
120     * note seconds_to_ticks(t) > t, so if t > 0x3f, so is
121     * tmrval=seconds_to_ticks(t). Check that the count in seconds isn't
122     * out of range on it's own (to avoid overflow in tmrval).
123     */
124    if (t < 0 || t > 0x3f)
125        return -EINVAL;
126    tmrval = seconds_to_ticks(t);
127
128    /* "Values of 0h-3h are ignored and should not be attempted" */
129    if (tmrval > 0x3f || tmrval < 0x04)
130        return -EINVAL;
131
132    /* Write new heartbeat to watchdog */
133    spin_lock_irqsave(&tco_lock, flags);
134    val = inb(TCO_TMR(tcobase));
135    val &= 0xc0;
136    val |= tmrval;
137    outb(val, TCO_TMR(tcobase));
138    val = inb(TCO_TMR(tcobase));
139
140    if ((val & 0x3f) != tmrval)
141        ret = -EINVAL;
142    spin_unlock_irqrestore(&tco_lock, flags);
143
144    if (ret)
145        return ret;
146
147    heartbeat = t;
148    return 0;
149}
150
151/*
152 * /dev/watchdog handling
153 */
154
155static int nv_tco_open(struct inode *inode, struct file *file)
156{
157    /* /dev/watchdog can only be opened once */
158    if (test_and_set_bit(0, &timer_alive))
159        return -EBUSY;
160
161    /* Reload and activate timer */
162    tco_timer_keepalive();
163    tco_timer_start();
164    return nonseekable_open(inode, file);
165}
166
167static int nv_tco_release(struct inode *inode, struct file *file)
168{
169    /* Shut off the timer */
170    if (tco_expect_close == 42) {
171        tco_timer_stop();
172    } else {
173        pr_crit("Unexpected close, not stopping watchdog!\n");
174        tco_timer_keepalive();
175    }
176    clear_bit(0, &timer_alive);
177    tco_expect_close = 0;
178    return 0;
179}
180
181static ssize_t nv_tco_write(struct file *file, const char __user *data,
182                size_t len, loff_t *ppos)
183{
184    /* See if we got the magic character 'V' and reload the timer */
185    if (len) {
186        if (!nowayout) {
187            size_t i;
188
189            /*
190             * note: just in case someone wrote the magic character
191             * five months ago...
192             */
193            tco_expect_close = 0;
194
195            /*
196             * scan to see whether or not we got the magic
197             * character
198             */
199            for (i = 0; i != len; i++) {
200                char c;
201                if (get_user(c, data + i))
202                    return -EFAULT;
203                if (c == 'V')
204                    tco_expect_close = 42;
205            }
206        }
207
208        /* someone wrote to us, we should reload the timer */
209        tco_timer_keepalive();
210    }
211    return len;
212}
213
214static long nv_tco_ioctl(struct file *file, unsigned int cmd,
215             unsigned long arg)
216{
217    int new_options, retval = -EINVAL;
218    int new_heartbeat;
219    void __user *argp = (void __user *)arg;
220    int __user *p = argp;
221    static const struct watchdog_info ident = {
222        .options = WDIOF_SETTIMEOUT |
223                    WDIOF_KEEPALIVEPING |
224                    WDIOF_MAGICCLOSE,
225        .firmware_version = 0,
226        .identity = TCO_MODULE_NAME,
227    };
228
229    switch (cmd) {
230    case WDIOC_GETSUPPORT:
231        return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
232    case WDIOC_GETSTATUS:
233    case WDIOC_GETBOOTSTATUS:
234        return put_user(0, p);
235    case WDIOC_SETOPTIONS:
236        if (get_user(new_options, p))
237            return -EFAULT;
238        if (new_options & WDIOS_DISABLECARD) {
239            tco_timer_stop();
240            retval = 0;
241        }
242        if (new_options & WDIOS_ENABLECARD) {
243            tco_timer_keepalive();
244            tco_timer_start();
245            retval = 0;
246        }
247        return retval;
248    case WDIOC_KEEPALIVE:
249        tco_timer_keepalive();
250        return 0;
251    case WDIOC_SETTIMEOUT:
252        if (get_user(new_heartbeat, p))
253            return -EFAULT;
254        if (tco_timer_set_heartbeat(new_heartbeat))
255            return -EINVAL;
256        tco_timer_keepalive();
257        /* Fall through */
258    case WDIOC_GETTIMEOUT:
259        return put_user(heartbeat, p);
260    default:
261        return -ENOTTY;
262    }
263}
264
265/*
266 * Kernel Interfaces
267 */
268
269static const struct file_operations nv_tco_fops = {
270    .owner = THIS_MODULE,
271    .llseek = no_llseek,
272    .write = nv_tco_write,
273    .unlocked_ioctl = nv_tco_ioctl,
274    .open = nv_tco_open,
275    .release = nv_tco_release,
276};
277
278static struct miscdevice nv_tco_miscdev = {
279    .minor = WATCHDOG_MINOR,
280    .name = "watchdog",
281    .fops = &nv_tco_fops,
282};
283
284/*
285 * Data for PCI driver interface
286 *
287 * This data only exists for exporting the supported
288 * PCI ids via MODULE_DEVICE_TABLE. We do not actually
289 * register a pci_driver, because someone else might one day
290 * want to register another driver on the same PCI id.
291 */
292static DEFINE_PCI_DEVICE_TABLE(tco_pci_tbl) = {
293    { PCI_VENDOR_ID_NVIDIA, PCI_DEVICE_ID_NVIDIA_NFORCE_MCP51_SMBUS,
294      PCI_ANY_ID, PCI_ANY_ID, },
295    { PCI_VENDOR_ID_NVIDIA, PCI_DEVICE_ID_NVIDIA_NFORCE_MCP55_SMBUS,
296      PCI_ANY_ID, PCI_ANY_ID, },
297    { 0, }, /* End of list */
298};
299MODULE_DEVICE_TABLE(pci, tco_pci_tbl);
300
301/*
302 * Init & exit routines
303 */
304
305static unsigned char __devinit nv_tco_getdevice(void)
306{
307    struct pci_dev *dev = NULL;
308    u32 val;
309
310    /* Find the PCI device */
311    for_each_pci_dev(dev) {
312        if (pci_match_id(tco_pci_tbl, dev) != NULL) {
313            tco_pci = dev;
314            break;
315        }
316    }
317
318    if (!tco_pci)
319        return 0;
320
321    /* Find the base io port */
322    pci_read_config_dword(tco_pci, 0x64, &val);
323    val &= 0xffff;
324    if (val == 0x0001 || val == 0x0000) {
325        /* Something is wrong here, bar isn't setup */
326        pr_err("failed to get tcobase address\n");
327        return 0;
328    }
329    val &= 0xff00;
330    tcobase = val + 0x40;
331
332    if (!request_region(tcobase, 0x10, "NV TCO")) {
333        pr_err("I/O address 0x%04x already in use\n", tcobase);
334        return 0;
335    }
336
337    /* Set a reasonable heartbeat before we stop the timer */
338    tco_timer_set_heartbeat(30);
339
340    /*
341     * Stop the TCO before we change anything so we don't race with
342     * a zeroed timer.
343     */
344    tco_timer_keepalive();
345    tco_timer_stop();
346
347    /* Disable SMI caused by TCO */
348    if (!request_region(MCP51_SMI_EN(tcobase), 4, "NV TCO")) {
349        pr_err("I/O address 0x%04x already in use\n",
350               MCP51_SMI_EN(tcobase));
351        goto out;
352    }
353    val = inl(MCP51_SMI_EN(tcobase));
354    val &= ~MCP51_SMI_EN_TCO;
355    outl(val, MCP51_SMI_EN(tcobase));
356    val = inl(MCP51_SMI_EN(tcobase));
357    release_region(MCP51_SMI_EN(tcobase), 4);
358    if (val & MCP51_SMI_EN_TCO) {
359        pr_err("Could not disable SMI caused by TCO\n");
360        goto out;
361    }
362
363    /* Check chipset's NO_REBOOT bit */
364    pci_read_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, &val);
365    val |= MCP51_SMBUS_SETUP_B_TCO_REBOOT;
366    pci_write_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, val);
367    pci_read_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, &val);
368    if (!(val & MCP51_SMBUS_SETUP_B_TCO_REBOOT)) {
369        pr_err("failed to reset NO_REBOOT flag, reboot disabled by hardware\n");
370        goto out;
371    }
372
373    return 1;
374out:
375    release_region(tcobase, 0x10);
376    return 0;
377}
378
379static int __devinit nv_tco_init(struct platform_device *dev)
380{
381    int ret;
382
383    /* Check whether or not the hardware watchdog is there */
384    if (!nv_tco_getdevice())
385        return -ENODEV;
386
387    /* Check to see if last reboot was due to watchdog timeout */
388    pr_info("Watchdog reboot %sdetected\n",
389        inl(TCO_STS(tcobase)) & TCO_STS_TCO2TO_STS ? "" : "not ");
390
391    /* Clear out the old status */
392    outl(TCO_STS_RESET, TCO_STS(tcobase));
393
394    /*
395     * Check that the heartbeat value is within it's range.
396     * If not, reset to the default.
397     */
398    if (tco_timer_set_heartbeat(heartbeat)) {
399        heartbeat = WATCHDOG_HEARTBEAT;
400        tco_timer_set_heartbeat(heartbeat);
401        pr_info("heartbeat value must be 2<heartbeat<39, using %d\n",
402            heartbeat);
403    }
404
405    ret = misc_register(&nv_tco_miscdev);
406    if (ret != 0) {
407        pr_err("cannot register miscdev on minor=%d (err=%d)\n",
408               WATCHDOG_MINOR, ret);
409        goto unreg_region;
410    }
411
412    clear_bit(0, &timer_alive);
413
414    tco_timer_stop();
415
416    pr_info("initialized (0x%04x). heartbeat=%d sec (nowayout=%d)\n",
417        tcobase, heartbeat, nowayout);
418
419    return 0;
420
421unreg_region:
422    release_region(tcobase, 0x10);
423    return ret;
424}
425
426static void __devexit nv_tco_cleanup(void)
427{
428    u32 val;
429
430    /* Stop the timer before we leave */
431    if (!nowayout)
432        tco_timer_stop();
433
434    /* Set the NO_REBOOT bit to prevent later reboots, just for sure */
435    pci_read_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, &val);
436    val &= ~MCP51_SMBUS_SETUP_B_TCO_REBOOT;
437    pci_write_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, val);
438    pci_read_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, &val);
439    if (val & MCP51_SMBUS_SETUP_B_TCO_REBOOT) {
440        pr_crit("Couldn't unset REBOOT bit. Machine may soon reset\n");
441    }
442
443    /* Deregister */
444    misc_deregister(&nv_tco_miscdev);
445    release_region(tcobase, 0x10);
446}
447
448static int __devexit nv_tco_remove(struct platform_device *dev)
449{
450    if (tcobase)
451        nv_tco_cleanup();
452
453    return 0;
454}
455
456static void nv_tco_shutdown(struct platform_device *dev)
457{
458    u32 val;
459
460    tco_timer_stop();
461
462    /* Some BIOSes fail the POST (once) if the NO_REBOOT flag is not
463     * unset during shutdown. */
464    pci_read_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, &val);
465    val &= ~MCP51_SMBUS_SETUP_B_TCO_REBOOT;
466    pci_write_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, val);
467}
468
469static struct platform_driver nv_tco_driver = {
470    .probe = nv_tco_init,
471    .remove = __devexit_p(nv_tco_remove),
472    .shutdown = nv_tco_shutdown,
473    .driver = {
474        .owner = THIS_MODULE,
475        .name = TCO_MODULE_NAME,
476    },
477};
478
479static int __init nv_tco_init_module(void)
480{
481    int err;
482
483    pr_info("NV TCO WatchDog Timer Driver v%s\n", TCO_VERSION);
484
485    err = platform_driver_register(&nv_tco_driver);
486    if (err)
487        return err;
488
489    nv_tco_platform_device = platform_device_register_simple(
490                    TCO_MODULE_NAME, -1, NULL, 0);
491    if (IS_ERR(nv_tco_platform_device)) {
492        err = PTR_ERR(nv_tco_platform_device);
493        goto unreg_platform_driver;
494    }
495
496    return 0;
497
498unreg_platform_driver:
499    platform_driver_unregister(&nv_tco_driver);
500    return err;
501}
502
503static void __exit nv_tco_cleanup_module(void)
504{
505    platform_device_unregister(nv_tco_platform_device);
506    platform_driver_unregister(&nv_tco_driver);
507    pr_info("NV TCO Watchdog Module Unloaded\n");
508}
509
510module_init(nv_tco_init_module);
511module_exit(nv_tco_cleanup_module);
512
513MODULE_AUTHOR("Mike Waychison");
514MODULE_DESCRIPTION("TCO timer driver for NV chipsets");
515MODULE_LICENSE("GPL");
516MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
517

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