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nv_tco.c
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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 <[email protected]>, 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 <[email protected]>
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 |
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 DEFINE_PCI_DEVICE_TABLE(tco_pci_tbl) = {
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 __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);
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 __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)) {
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 __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);
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 __devexit 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);
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 = __devexit_p(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");