1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * nv_tco 0.01: TCO timer driver for NV chipsets
4 *
5 * (c) Copyright 2005 Google Inc., All Rights Reserved.
6 *
7 * Based off i8xx_tco.c:
8 * (c) Copyright 2000 kernel concepts <nils@kernelconcepts.de>, All Rights
9 * Reserved.
10 * https://www.kernelconcepts.de
11 *
12 * TCO timer driver for NV chipsets
13 * based on softdog.c by Alan Cox <alan@redhat.com>
14 */
15
16 /*
17 * Includes, defines, variables, module parameters, ...
18 */
19
20 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
21
22 #include <linux/module.h>
23 #include <linux/moduleparam.h>
24 #include <linux/types.h>
25 #include <linux/miscdevice.h>
26 #include <linux/watchdog.h>
27 #include <linux/init.h>
28 #include <linux/fs.h>
29 #include <linux/pci.h>
30 #include <linux/ioport.h>
31 #include <linux/jiffies.h>
32 #include <linux/platform_device.h>
33 #include <linux/uaccess.h>
34 #include <linux/io.h>
35
36 #include "nv_tco.h"
37
38 /* Module and version information */
39 #define TCO_VERSION "0.01"
40 #define TCO_MODULE_NAME "NV_TCO"
41 #define TCO_DRIVER_NAME TCO_MODULE_NAME ", v" TCO_VERSION
42
43 /* internal variables */
44 static unsigned int tcobase;
45 static DEFINE_SPINLOCK(tco_lock); /* Guards the hardware */
46 static unsigned long timer_alive;
47 static char tco_expect_close;
48 static struct pci_dev *tco_pci;
49
50 /* the watchdog platform device */
51 static struct platform_device *nv_tco_platform_device;
52
53 /* module parameters */
54 #define WATCHDOG_HEARTBEAT 30 /* 30 sec default heartbeat (2<heartbeat<39) */
55 static int heartbeat = WATCHDOG_HEARTBEAT; /* in seconds */
56 module_param(heartbeat, int, 0);
57 MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds. (2<heartbeat<39, "
58 "default=" __MODULE_STRING(WATCHDOG_HEARTBEAT) ")");
59
60 static bool nowayout = WATCHDOG_NOWAYOUT;
61 module_param(nowayout, bool, 0);
62 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started"
63 " (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
64
65 /*
66 * Some TCO specific functions
67 */
seconds_to_ticks(int seconds)68 static inline unsigned char seconds_to_ticks(int seconds)
69 {
70 /* the internal timer is stored as ticks which decrement
71 * every 0.6 seconds */
72 return (seconds * 10) / 6;
73 }
74
tco_timer_start(void)75 static void tco_timer_start(void)
76 {
77 u32 val;
78 unsigned long flags;
79
80 spin_lock_irqsave(&tco_lock, flags);
81 val = inl(TCO_CNT(tcobase));
82 val &= ~TCO_CNT_TCOHALT;
83 outl(val, TCO_CNT(tcobase));
84 spin_unlock_irqrestore(&tco_lock, flags);
85 }
86
tco_timer_stop(void)87 static void tco_timer_stop(void)
88 {
89 u32 val;
90 unsigned long flags;
91
92 spin_lock_irqsave(&tco_lock, flags);
93 val = inl(TCO_CNT(tcobase));
94 val |= TCO_CNT_TCOHALT;
95 outl(val, TCO_CNT(tcobase));
96 spin_unlock_irqrestore(&tco_lock, flags);
97 }
98
tco_timer_keepalive(void)99 static void tco_timer_keepalive(void)
100 {
101 unsigned long flags;
102
103 spin_lock_irqsave(&tco_lock, flags);
104 outb(0x01, TCO_RLD(tcobase));
105 spin_unlock_irqrestore(&tco_lock, flags);
106 }
107
tco_timer_set_heartbeat(int t)108 static int tco_timer_set_heartbeat(int t)
109 {
110 int ret = 0;
111 unsigned char tmrval;
112 unsigned long flags;
113 u8 val;
114
115 /*
116 * note seconds_to_ticks(t) > t, so if t > 0x3f, so is
117 * tmrval=seconds_to_ticks(t). Check that the count in seconds isn't
118 * out of range on it's own (to avoid overflow in tmrval).
119 */
120 if (t < 0 || t > 0x3f)
121 return -EINVAL;
122 tmrval = seconds_to_ticks(t);
123
124 /* "Values of 0h-3h are ignored and should not be attempted" */
125 if (tmrval > 0x3f || tmrval < 0x04)
126 return -EINVAL;
127
128 /* Write new heartbeat to watchdog */
129 spin_lock_irqsave(&tco_lock, flags);
130 val = inb(TCO_TMR(tcobase));
131 val &= 0xc0;
132 val |= tmrval;
133 outb(val, TCO_TMR(tcobase));
134 val = inb(TCO_TMR(tcobase));
135
136 if ((val & 0x3f) != tmrval)
137 ret = -EINVAL;
138 spin_unlock_irqrestore(&tco_lock, flags);
139
140 if (ret)
141 return ret;
142
143 heartbeat = t;
144 return 0;
145 }
146
147 /*
148 * /dev/watchdog handling
149 */
150
nv_tco_open(struct inode * inode,struct file * file)151 static int nv_tco_open(struct inode *inode, struct file *file)
152 {
153 /* /dev/watchdog can only be opened once */
154 if (test_and_set_bit(0, &timer_alive))
155 return -EBUSY;
156
157 /* Reload and activate timer */
158 tco_timer_keepalive();
159 tco_timer_start();
160 return stream_open(inode, file);
161 }
162
nv_tco_release(struct inode * inode,struct file * file)163 static int nv_tco_release(struct inode *inode, struct file *file)
164 {
165 /* Shut off the timer */
166 if (tco_expect_close == 42) {
167 tco_timer_stop();
168 } else {
169 pr_crit("Unexpected close, not stopping watchdog!\n");
170 tco_timer_keepalive();
171 }
172 clear_bit(0, &timer_alive);
173 tco_expect_close = 0;
174 return 0;
175 }
176
nv_tco_write(struct file * file,const char __user * data,size_t len,loff_t * ppos)177 static ssize_t nv_tco_write(struct file *file, const char __user *data,
178 size_t len, loff_t *ppos)
179 {
180 /* See if we got the magic character 'V' and reload the timer */
181 if (len) {
182 if (!nowayout) {
183 size_t i;
184
185 /*
186 * note: just in case someone wrote the magic character
187 * five months ago...
188 */
189 tco_expect_close = 0;
190
191 /*
192 * scan to see whether or not we got the magic
193 * character
194 */
195 for (i = 0; i != len; i++) {
196 char c;
197 if (get_user(c, data + i))
198 return -EFAULT;
199 if (c == 'V')
200 tco_expect_close = 42;
201 }
202 }
203
204 /* someone wrote to us, we should reload the timer */
205 tco_timer_keepalive();
206 }
207 return len;
208 }
209
nv_tco_ioctl(struct file * file,unsigned int cmd,unsigned long arg)210 static long nv_tco_ioctl(struct file *file, unsigned int cmd,
211 unsigned long arg)
212 {
213 int new_options, retval = -EINVAL;
214 int new_heartbeat;
215 void __user *argp = (void __user *)arg;
216 int __user *p = argp;
217 static const struct watchdog_info ident = {
218 .options = WDIOF_SETTIMEOUT |
219 WDIOF_KEEPALIVEPING |
220 WDIOF_MAGICCLOSE,
221 .firmware_version = 0,
222 .identity = TCO_MODULE_NAME,
223 };
224
225 switch (cmd) {
226 case WDIOC_GETSUPPORT:
227 return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
228 case WDIOC_GETSTATUS:
229 case WDIOC_GETBOOTSTATUS:
230 return put_user(0, p);
231 case WDIOC_SETOPTIONS:
232 if (get_user(new_options, p))
233 return -EFAULT;
234 if (new_options & WDIOS_DISABLECARD) {
235 tco_timer_stop();
236 retval = 0;
237 }
238 if (new_options & WDIOS_ENABLECARD) {
239 tco_timer_keepalive();
240 tco_timer_start();
241 retval = 0;
242 }
243 return retval;
244 case WDIOC_KEEPALIVE:
245 tco_timer_keepalive();
246 return 0;
247 case WDIOC_SETTIMEOUT:
248 if (get_user(new_heartbeat, p))
249 return -EFAULT;
250 if (tco_timer_set_heartbeat(new_heartbeat))
251 return -EINVAL;
252 tco_timer_keepalive();
253 fallthrough;
254 case WDIOC_GETTIMEOUT:
255 return put_user(heartbeat, p);
256 default:
257 return -ENOTTY;
258 }
259 }
260
261 /*
262 * Kernel Interfaces
263 */
264
265 static const struct file_operations nv_tco_fops = {
266 .owner = THIS_MODULE,
267 .write = nv_tco_write,
268 .unlocked_ioctl = nv_tco_ioctl,
269 .compat_ioctl = compat_ptr_ioctl,
270 .open = nv_tco_open,
271 .release = nv_tco_release,
272 };
273
274 static struct miscdevice nv_tco_miscdev = {
275 .minor = WATCHDOG_MINOR,
276 .name = "watchdog",
277 .fops = &nv_tco_fops,
278 };
279
280 /*
281 * Data for PCI driver interface
282 *
283 * This data only exists for exporting the supported
284 * PCI ids via MODULE_DEVICE_TABLE. We do not actually
285 * register a pci_driver, because someone else might one day
286 * want to register another driver on the same PCI id.
287 */
288 static const struct pci_device_id tco_pci_tbl[] = {
289 { PCI_VENDOR_ID_NVIDIA, PCI_DEVICE_ID_NVIDIA_NFORCE_MCP51_SMBUS,
290 PCI_ANY_ID, PCI_ANY_ID, },
291 { PCI_VENDOR_ID_NVIDIA, PCI_DEVICE_ID_NVIDIA_NFORCE_MCP55_SMBUS,
292 PCI_ANY_ID, PCI_ANY_ID, },
293 { PCI_VENDOR_ID_NVIDIA, PCI_DEVICE_ID_NVIDIA_NFORCE_MCP78S_SMBUS,
294 PCI_ANY_ID, PCI_ANY_ID, },
295 { PCI_VENDOR_ID_NVIDIA, PCI_DEVICE_ID_NVIDIA_NFORCE_MCP79_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
nv_tco_getdevice(void)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
nv_tco_init(struct platform_device * dev)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
nv_tco_cleanup(void)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
nv_tco_remove(struct platform_device * dev)448 static void nv_tco_remove(struct platform_device *dev)
449 {
450 if (tcobase)
451 nv_tco_cleanup();
452 }
453
nv_tco_shutdown(struct platform_device * dev)454 static void nv_tco_shutdown(struct platform_device *dev)
455 {
456 u32 val;
457
458 tco_timer_stop();
459
460 /* Some BIOSes fail the POST (once) if the NO_REBOOT flag is not
461 * unset during shutdown. */
462 pci_read_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, &val);
463 val &= ~MCP51_SMBUS_SETUP_B_TCO_REBOOT;
464 pci_write_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, val);
465 }
466
467 static struct platform_driver nv_tco_driver = {
468 .probe = nv_tco_init,
469 .remove_new = nv_tco_remove,
470 .shutdown = nv_tco_shutdown,
471 .driver = {
472 .name = TCO_MODULE_NAME,
473 },
474 };
475
nv_tco_init_module(void)476 static int __init nv_tco_init_module(void)
477 {
478 int err;
479
480 pr_info("NV TCO WatchDog Timer Driver v%s\n", TCO_VERSION);
481
482 err = platform_driver_register(&nv_tco_driver);
483 if (err)
484 return err;
485
486 nv_tco_platform_device = platform_device_register_simple(
487 TCO_MODULE_NAME, -1, NULL, 0);
488 if (IS_ERR(nv_tco_platform_device)) {
489 err = PTR_ERR(nv_tco_platform_device);
490 goto unreg_platform_driver;
491 }
492
493 return 0;
494
495 unreg_platform_driver:
496 platform_driver_unregister(&nv_tco_driver);
497 return err;
498 }
499
nv_tco_cleanup_module(void)500 static void __exit nv_tco_cleanup_module(void)
501 {
502 platform_device_unregister(nv_tco_platform_device);
503 platform_driver_unregister(&nv_tco_driver);
504 pr_info("NV TCO Watchdog Module Unloaded\n");
505 }
506
507 module_init(nv_tco_init_module);
508 module_exit(nv_tco_cleanup_module);
509
510 MODULE_AUTHOR("Mike Waychison");
511 MODULE_DESCRIPTION("TCO timer driver for NV chipsets");
512 MODULE_LICENSE("GPL");
513