a0fabf6f92b02c7f849be81fdf881842100ec2d8
[sfrench/cifs-2.6.git] / 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 */
48 static unsigned int tcobase;
49 static DEFINE_SPINLOCK(tco_lock);       /* Guards the hardware */
50 static unsigned long timer_alive;
51 static char tco_expect_close;
52 static struct pci_dev *tco_pci;
53
54 /* the watchdog platform device */
55 static struct platform_device *nv_tco_platform_device;
56
57 /* module parameters */
58 #define WATCHDOG_HEARTBEAT 30   /* 30 sec default heartbeat (2<heartbeat<39) */
59 static int heartbeat = WATCHDOG_HEARTBEAT;  /* in seconds */
60 module_param(heartbeat, int, 0);
61 MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds. (2<heartbeat<39, "
62                             "default=" __MODULE_STRING(WATCHDOG_HEARTBEAT) ")");
63
64 static bool nowayout = WATCHDOG_NOWAYOUT;
65 module_param(nowayout, bool, 0);
66 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started"
67                 " (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
68
69 /*
70  * Some TCO specific functions
71  */
72 static 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
79 static 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
91 static 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
103 static 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
112 static 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
155 static 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
167 static 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
181 static 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
214 static 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
269 static 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
278 static 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  */
292 static const struct pci_device_id 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         { PCI_VENDOR_ID_NVIDIA, PCI_DEVICE_ID_NVIDIA_NFORCE_MCP78S_SMBUS,
298           PCI_ANY_ID, PCI_ANY_ID, },
299         { PCI_VENDOR_ID_NVIDIA, PCI_DEVICE_ID_NVIDIA_NFORCE_MCP79_SMBUS,
300           PCI_ANY_ID, PCI_ANY_ID, },
301         { 0, },                 /* End of list */
302 };
303 MODULE_DEVICE_TABLE(pci, tco_pci_tbl);
304
305 /*
306  *      Init & exit routines
307  */
308
309 static unsigned char nv_tco_getdevice(void)
310 {
311         struct pci_dev *dev = NULL;
312         u32 val;
313
314         /* Find the PCI device */
315         for_each_pci_dev(dev) {
316                 if (pci_match_id(tco_pci_tbl, dev) != NULL) {
317                         tco_pci = dev;
318                         break;
319                 }
320         }
321
322         if (!tco_pci)
323                 return 0;
324
325         /* Find the base io port */
326         pci_read_config_dword(tco_pci, 0x64, &val);
327         val &= 0xffff;
328         if (val == 0x0001 || val == 0x0000) {
329                 /* Something is wrong here, bar isn't setup */
330                 pr_err("failed to get tcobase address\n");
331                 return 0;
332         }
333         val &= 0xff00;
334         tcobase = val + 0x40;
335
336         if (!request_region(tcobase, 0x10, "NV TCO")) {
337                 pr_err("I/O address 0x%04x already in use\n", tcobase);
338                 return 0;
339         }
340
341         /* Set a reasonable heartbeat before we stop the timer */
342         tco_timer_set_heartbeat(30);
343
344         /*
345          * Stop the TCO before we change anything so we don't race with
346          * a zeroed timer.
347          */
348         tco_timer_keepalive();
349         tco_timer_stop();
350
351         /* Disable SMI caused by TCO */
352         if (!request_region(MCP51_SMI_EN(tcobase), 4, "NV TCO")) {
353                 pr_err("I/O address 0x%04x already in use\n",
354                        MCP51_SMI_EN(tcobase));
355                 goto out;
356         }
357         val = inl(MCP51_SMI_EN(tcobase));
358         val &= ~MCP51_SMI_EN_TCO;
359         outl(val, MCP51_SMI_EN(tcobase));
360         val = inl(MCP51_SMI_EN(tcobase));
361         release_region(MCP51_SMI_EN(tcobase), 4);
362         if (val & MCP51_SMI_EN_TCO) {
363                 pr_err("Could not disable SMI caused by TCO\n");
364                 goto out;
365         }
366
367         /* Check chipset's NO_REBOOT bit */
368         pci_read_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, &val);
369         val |= MCP51_SMBUS_SETUP_B_TCO_REBOOT;
370         pci_write_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, val);
371         pci_read_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, &val);
372         if (!(val & MCP51_SMBUS_SETUP_B_TCO_REBOOT)) {
373                 pr_err("failed to reset NO_REBOOT flag, reboot disabled by hardware\n");
374                 goto out;
375         }
376
377         return 1;
378 out:
379         release_region(tcobase, 0x10);
380         return 0;
381 }
382
383 static int nv_tco_init(struct platform_device *dev)
384 {
385         int ret;
386
387         /* Check whether or not the hardware watchdog is there */
388         if (!nv_tco_getdevice())
389                 return -ENODEV;
390
391         /* Check to see if last reboot was due to watchdog timeout */
392         pr_info("Watchdog reboot %sdetected\n",
393                 inl(TCO_STS(tcobase)) & TCO_STS_TCO2TO_STS ? "" : "not ");
394
395         /* Clear out the old status */
396         outl(TCO_STS_RESET, TCO_STS(tcobase));
397
398         /*
399          * Check that the heartbeat value is within it's range.
400          * If not, reset to the default.
401          */
402         if (tco_timer_set_heartbeat(heartbeat)) {
403                 heartbeat = WATCHDOG_HEARTBEAT;
404                 tco_timer_set_heartbeat(heartbeat);
405                 pr_info("heartbeat value must be 2<heartbeat<39, using %d\n",
406                         heartbeat);
407         }
408
409         ret = misc_register(&nv_tco_miscdev);
410         if (ret != 0) {
411                 pr_err("cannot register miscdev on minor=%d (err=%d)\n",
412                        WATCHDOG_MINOR, ret);
413                 goto unreg_region;
414         }
415
416         clear_bit(0, &timer_alive);
417
418         tco_timer_stop();
419
420         pr_info("initialized (0x%04x). heartbeat=%d sec (nowayout=%d)\n",
421                 tcobase, heartbeat, nowayout);
422
423         return 0;
424
425 unreg_region:
426         release_region(tcobase, 0x10);
427         return ret;
428 }
429
430 static void nv_tco_cleanup(void)
431 {
432         u32 val;
433
434         /* Stop the timer before we leave */
435         if (!nowayout)
436                 tco_timer_stop();
437
438         /* Set the NO_REBOOT bit to prevent later reboots, just for sure */
439         pci_read_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, &val);
440         val &= ~MCP51_SMBUS_SETUP_B_TCO_REBOOT;
441         pci_write_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, val);
442         pci_read_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, &val);
443         if (val & MCP51_SMBUS_SETUP_B_TCO_REBOOT) {
444                 pr_crit("Couldn't unset REBOOT bit.  Machine may soon reset\n");
445         }
446
447         /* Deregister */
448         misc_deregister(&nv_tco_miscdev);
449         release_region(tcobase, 0x10);
450 }
451
452 static int nv_tco_remove(struct platform_device *dev)
453 {
454         if (tcobase)
455                 nv_tco_cleanup();
456
457         return 0;
458 }
459
460 static void nv_tco_shutdown(struct platform_device *dev)
461 {
462         u32 val;
463
464         tco_timer_stop();
465
466         /* Some BIOSes fail the POST (once) if the NO_REBOOT flag is not
467          * unset during shutdown. */
468         pci_read_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, &val);
469         val &= ~MCP51_SMBUS_SETUP_B_TCO_REBOOT;
470         pci_write_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, val);
471 }
472
473 static struct platform_driver nv_tco_driver = {
474         .probe          = nv_tco_init,
475         .remove         = nv_tco_remove,
476         .shutdown       = nv_tco_shutdown,
477         .driver         = {
478                 .name   = TCO_MODULE_NAME,
479         },
480 };
481
482 static int __init nv_tco_init_module(void)
483 {
484         int err;
485
486         pr_info("NV TCO WatchDog Timer Driver v%s\n", TCO_VERSION);
487
488         err = platform_driver_register(&nv_tco_driver);
489         if (err)
490                 return err;
491
492         nv_tco_platform_device = platform_device_register_simple(
493                                         TCO_MODULE_NAME, -1, NULL, 0);
494         if (IS_ERR(nv_tco_platform_device)) {
495                 err = PTR_ERR(nv_tco_platform_device);
496                 goto unreg_platform_driver;
497         }
498
499         return 0;
500
501 unreg_platform_driver:
502         platform_driver_unregister(&nv_tco_driver);
503         return err;
504 }
505
506 static void __exit nv_tco_cleanup_module(void)
507 {
508         platform_device_unregister(nv_tco_platform_device);
509         platform_driver_unregister(&nv_tco_driver);
510         pr_info("NV TCO Watchdog Module Unloaded\n");
511 }
512
513 module_init(nv_tco_init_module);
514 module_exit(nv_tco_cleanup_module);
515
516 MODULE_AUTHOR("Mike Waychison");
517 MODULE_DESCRIPTION("TCO timer driver for NV chipsets");
518 MODULE_LICENSE("GPL");