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Linux/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         { 0, },                 /* End of list */
298 };
299 MODULE_DEVICE_TABLE(pci, tco_pci_tbl);
300 
301 /*
302  *      Init & exit routines
303  */
304 
305 static unsigned char 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;
374 out:
375         release_region(tcobase, 0x10);
376         return 0;
377 }
378 
379 static int 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 
421 unreg_region:
422         release_region(tcobase, 0x10);
423         return ret;
424 }
425 
426 static void 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 
448 static int nv_tco_remove(struct platform_device *dev)
449 {
450         if (tcobase)
451                 nv_tco_cleanup();
452 
453         return 0;
454 }
455 
456 static 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 
469 static struct platform_driver nv_tco_driver = {
470         .probe          = nv_tco_init,
471         .remove         = nv_tco_remove,
472         .shutdown       = nv_tco_shutdown,
473         .driver         = {
474                 .owner  = THIS_MODULE,
475                 .name   = TCO_MODULE_NAME,
476         },
477 };
478 
479 static 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 
498 unreg_platform_driver:
499         platform_driver_unregister(&nv_tco_driver);
500         return err;
501 }
502 
503 static 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 
510 module_init(nv_tco_init_module);
511 module_exit(nv_tco_cleanup_module);
512 
513 MODULE_AUTHOR("Mike Waychison");
514 MODULE_DESCRIPTION("TCO timer driver for NV chipsets");
515 MODULE_LICENSE("GPL");
516 

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