1 /*
2 * i6300esb: Watchdog timer driver for Intel 6300ESB chipset
3 *
4 * (c) Copyright 2004 Google Inc.
5 * (c) Copyright 2005 David Härdeman <david@2gen.com>
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * as published by the Free Software Foundation; either version
10 * 2 of the License, or (at your option) any later version.
11 *
12 * based on i810-tco.c which is in turn based on softdog.c
13 *
14 * The timer is implemented in the following I/O controller hubs:
15 * (See the intel documentation on http://developer.intel.com.)
16 * 6300ESB chip : document number 300641-004
17 *
18 * 2004YYZZ Ross Biro
19 * Initial version 0.01
20 * 2004YYZZ Ross Biro
21 * Version 0.02
22 * 20050210 David Härdeman <david@2gen.com>
23 * Ported driver to kernel 2.6
24 */
25
26 /*
27 * Includes, defines, variables, module parameters, ...
28 */
29
30 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
31
32 #include <linux/module.h>
33 #include <linux/types.h>
34 #include <linux/kernel.h>
35 #include <linux/fs.h>
36 #include <linux/mm.h>
37 #include <linux/miscdevice.h>
38 #include <linux/watchdog.h>
39 #include <linux/init.h>
40 #include <linux/pci.h>
41 #include <linux/ioport.h>
42 #include <linux/uaccess.h>
43 #include <linux/io.h>
44
45 /* Module and version information */
46 #define ESB_VERSION "0.05"
47 #define ESB_MODULE_NAME "i6300ESB timer"
48 #define ESB_DRIVER_NAME ESB_MODULE_NAME ", v" ESB_VERSION
49
50 /* PCI configuration registers */
51 #define ESB_CONFIG_REG 0x60 /* Config register */
52 #define ESB_LOCK_REG 0x68 /* WDT lock register */
53
54 /* Memory mapped registers */
55 #define ESB_TIMER1_REG (BASEADDR + 0x00)/* Timer1 value after each reset */
56 #define ESB_TIMER2_REG (BASEADDR + 0x04)/* Timer2 value after each reset */
57 #define ESB_GINTSR_REG (BASEADDR + 0x08)/* General Interrupt Status Register */
58 #define ESB_RELOAD_REG (BASEADDR + 0x0c)/* Reload register */
59
60 /* Lock register bits */
61 #define ESB_WDT_FUNC (0x01 << 2) /* Watchdog functionality */
62 #define ESB_WDT_ENABLE (0x01 << 1) /* Enable WDT */
63 #define ESB_WDT_LOCK (0x01 << 0) /* Lock (nowayout) */
64
65 /* Config register bits */
66 #define ESB_WDT_REBOOT (0x01 << 5) /* Enable reboot on timeout */
67 #define ESB_WDT_FREQ (0x01 << 2) /* Decrement frequency */
68 #define ESB_WDT_INTTYPE (0x03 << 0) /* Interrupt type on timer1 timeout */
69
70 /* Reload register bits */
71 #define ESB_WDT_TIMEOUT (0x01 << 9) /* Watchdog timed out */
72 #define ESB_WDT_RELOAD (0x01 << 8) /* prevent timeout */
73
74 /* Magic constants */
75 #define ESB_UNLOCK1 0x80 /* Step 1 to unlock reset registers */
76 #define ESB_UNLOCK2 0x86 /* Step 2 to unlock reset registers */
77
78 /* internal variables */
79 static void __iomem *BASEADDR;
80 static DEFINE_SPINLOCK(esb_lock); /* Guards the hardware */
81 static unsigned long timer_alive;
82 static struct pci_dev *esb_pci;
83 static unsigned short triggered; /* The status of the watchdog upon boot */
84 static char esb_expect_close;
85
86 /* We can only use 1 card due to the /dev/watchdog restriction */
87 static int cards_found;
88
89 /* module parameters */
90 /* 30 sec default heartbeat (1 < heartbeat < 2*1023) */
91 #define WATCHDOG_HEARTBEAT 30
92 static int heartbeat = WATCHDOG_HEARTBEAT; /* in seconds */
93 module_param(heartbeat, int, 0);
94 MODULE_PARM_DESC(heartbeat,
95 "Watchdog heartbeat in seconds. (1<heartbeat<2046, default="
96 __MODULE_STRING(WATCHDOG_HEARTBEAT) ")");
97
98 static bool nowayout = WATCHDOG_NOWAYOUT;
99 module_param(nowayout, bool, 0);
100 MODULE_PARM_DESC(nowayout,
101 "Watchdog cannot be stopped once started (default="
102 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
103
104 /*
105 * Some i6300ESB specific functions
106 */
107
108 /*
109 * Prepare for reloading the timer by unlocking the proper registers.
110 * This is performed by first writing 0x80 followed by 0x86 to the
111 * reload register. After this the appropriate registers can be written
112 * to once before they need to be unlocked again.
113 */
esb_unlock_registers(void)114 static inline void esb_unlock_registers(void)
115 {
116 writew(ESB_UNLOCK1, ESB_RELOAD_REG);
117 writew(ESB_UNLOCK2, ESB_RELOAD_REG);
118 }
119
esb_timer_start(void)120 static int esb_timer_start(void)
121 {
122 u8 val;
123
124 spin_lock(&esb_lock);
125 esb_unlock_registers();
126 writew(ESB_WDT_RELOAD, ESB_RELOAD_REG);
127 /* Enable or Enable + Lock? */
128 val = ESB_WDT_ENABLE | (nowayout ? ESB_WDT_LOCK : 0x00);
129 pci_write_config_byte(esb_pci, ESB_LOCK_REG, val);
130 spin_unlock(&esb_lock);
131 return 0;
132 }
133
esb_timer_stop(void)134 static int esb_timer_stop(void)
135 {
136 u8 val;
137
138 spin_lock(&esb_lock);
139 /* First, reset timers as suggested by the docs */
140 esb_unlock_registers();
141 writew(ESB_WDT_RELOAD, ESB_RELOAD_REG);
142 /* Then disable the WDT */
143 pci_write_config_byte(esb_pci, ESB_LOCK_REG, 0x0);
144 pci_read_config_byte(esb_pci, ESB_LOCK_REG, &val);
145 spin_unlock(&esb_lock);
146
147 /* Returns 0 if the timer was disabled, non-zero otherwise */
148 return val & ESB_WDT_ENABLE;
149 }
150
esb_timer_keepalive(void)151 static void esb_timer_keepalive(void)
152 {
153 spin_lock(&esb_lock);
154 esb_unlock_registers();
155 writew(ESB_WDT_RELOAD, ESB_RELOAD_REG);
156 /* FIXME: Do we need to flush anything here? */
157 spin_unlock(&esb_lock);
158 }
159
esb_timer_set_heartbeat(int time)160 static int esb_timer_set_heartbeat(int time)
161 {
162 u32 val;
163
164 if (time < 0x1 || time > (2 * 0x03ff))
165 return -EINVAL;
166
167 spin_lock(&esb_lock);
168
169 /* We shift by 9, so if we are passed a value of 1 sec,
170 * val will be 1 << 9 = 512, then write that to two
171 * timers => 2 * 512 = 1024 (which is decremented at 1KHz)
172 */
173 val = time << 9;
174
175 /* Write timer 1 */
176 esb_unlock_registers();
177 writel(val, ESB_TIMER1_REG);
178
179 /* Write timer 2 */
180 esb_unlock_registers();
181 writel(val, ESB_TIMER2_REG);
182
183 /* Reload */
184 esb_unlock_registers();
185 writew(ESB_WDT_RELOAD, ESB_RELOAD_REG);
186
187 /* FIXME: Do we need to flush everything out? */
188
189 /* Done */
190 heartbeat = time;
191 spin_unlock(&esb_lock);
192 return 0;
193 }
194
195 /*
196 * /dev/watchdog handling
197 */
198
esb_open(struct inode * inode,struct file * file)199 static int esb_open(struct inode *inode, struct file *file)
200 {
201 /* /dev/watchdog can only be opened once */
202 if (test_and_set_bit(0, &timer_alive))
203 return -EBUSY;
204
205 /* Reload and activate timer */
206 esb_timer_start();
207
208 return nonseekable_open(inode, file);
209 }
210
esb_release(struct inode * inode,struct file * file)211 static int esb_release(struct inode *inode, struct file *file)
212 {
213 /* Shut off the timer. */
214 if (esb_expect_close == 42)
215 esb_timer_stop();
216 else {
217 pr_crit("Unexpected close, not stopping watchdog!\n");
218 esb_timer_keepalive();
219 }
220 clear_bit(0, &timer_alive);
221 esb_expect_close = 0;
222 return 0;
223 }
224
esb_write(struct file * file,const char __user * data,size_t len,loff_t * ppos)225 static ssize_t esb_write(struct file *file, const char __user *data,
226 size_t len, loff_t *ppos)
227 {
228 /* See if we got the magic character 'V' and reload the timer */
229 if (len) {
230 if (!nowayout) {
231 size_t i;
232
233 /* note: just in case someone wrote the magic character
234 * five months ago... */
235 esb_expect_close = 0;
236
237 /* scan to see whether or not we got the
238 * magic character */
239 for (i = 0; i != len; i++) {
240 char c;
241 if (get_user(c, data + i))
242 return -EFAULT;
243 if (c == 'V')
244 esb_expect_close = 42;
245 }
246 }
247
248 /* someone wrote to us, we should reload the timer */
249 esb_timer_keepalive();
250 }
251 return len;
252 }
253
esb_ioctl(struct file * file,unsigned int cmd,unsigned long arg)254 static long esb_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
255 {
256 int new_options, retval = -EINVAL;
257 int new_heartbeat;
258 void __user *argp = (void __user *)arg;
259 int __user *p = argp;
260 static const struct watchdog_info ident = {
261 .options = WDIOF_SETTIMEOUT |
262 WDIOF_KEEPALIVEPING |
263 WDIOF_MAGICCLOSE,
264 .firmware_version = 0,
265 .identity = ESB_MODULE_NAME,
266 };
267
268 switch (cmd) {
269 case WDIOC_GETSUPPORT:
270 return copy_to_user(argp, &ident,
271 sizeof(ident)) ? -EFAULT : 0;
272
273 case WDIOC_GETSTATUS:
274 return put_user(0, p);
275
276 case WDIOC_GETBOOTSTATUS:
277 return put_user(triggered, p);
278
279 case WDIOC_SETOPTIONS:
280 {
281 if (get_user(new_options, p))
282 return -EFAULT;
283
284 if (new_options & WDIOS_DISABLECARD) {
285 esb_timer_stop();
286 retval = 0;
287 }
288
289 if (new_options & WDIOS_ENABLECARD) {
290 esb_timer_start();
291 retval = 0;
292 }
293 return retval;
294 }
295 case WDIOC_KEEPALIVE:
296 esb_timer_keepalive();
297 return 0;
298
299 case WDIOC_SETTIMEOUT:
300 {
301 if (get_user(new_heartbeat, p))
302 return -EFAULT;
303 if (esb_timer_set_heartbeat(new_heartbeat))
304 return -EINVAL;
305 esb_timer_keepalive();
306 /* Fall */
307 }
308 case WDIOC_GETTIMEOUT:
309 return put_user(heartbeat, p);
310 default:
311 return -ENOTTY;
312 }
313 }
314
315 /*
316 * Kernel Interfaces
317 */
318
319 static const struct file_operations esb_fops = {
320 .owner = THIS_MODULE,
321 .llseek = no_llseek,
322 .write = esb_write,
323 .unlocked_ioctl = esb_ioctl,
324 .open = esb_open,
325 .release = esb_release,
326 };
327
328 static struct miscdevice esb_miscdev = {
329 .minor = WATCHDOG_MINOR,
330 .name = "watchdog",
331 .fops = &esb_fops,
332 };
333
334 /*
335 * Data for PCI driver interface
336 */
337 static DEFINE_PCI_DEVICE_TABLE(esb_pci_tbl) = {
338 { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_ESB_9), },
339 { 0, }, /* End of list */
340 };
341 MODULE_DEVICE_TABLE(pci, esb_pci_tbl);
342
343 /*
344 * Init & exit routines
345 */
346
esb_getdevice(struct pci_dev * pdev)347 static unsigned char __devinit esb_getdevice(struct pci_dev *pdev)
348 {
349 if (pci_enable_device(pdev)) {
350 pr_err("failed to enable device\n");
351 goto err_devput;
352 }
353
354 if (pci_request_region(pdev, 0, ESB_MODULE_NAME)) {
355 pr_err("failed to request region\n");
356 goto err_disable;
357 }
358
359 BASEADDR = pci_ioremap_bar(pdev, 0);
360 if (BASEADDR == NULL) {
361 /* Something's wrong here, BASEADDR has to be set */
362 pr_err("failed to get BASEADDR\n");
363 goto err_release;
364 }
365
366 /* Done */
367 esb_pci = pdev;
368 return 1;
369
370 err_release:
371 pci_release_region(pdev, 0);
372 err_disable:
373 pci_disable_device(pdev);
374 err_devput:
375 return 0;
376 }
377
esb_initdevice(void)378 static void __devinit esb_initdevice(void)
379 {
380 u8 val1;
381 u16 val2;
382
383 /*
384 * Config register:
385 * Bit 5 : 0 = Enable WDT_OUTPUT
386 * Bit 2 : 0 = set the timer frequency to the PCI clock
387 * divided by 2^15 (approx 1KHz).
388 * Bits 1:0 : 11 = WDT_INT_TYPE Disabled.
389 * The watchdog has two timers, it can be setup so that the
390 * expiry of timer1 results in an interrupt and the expiry of
391 * timer2 results in a reboot. We set it to not generate
392 * any interrupts as there is not much we can do with it
393 * right now.
394 */
395 pci_write_config_word(esb_pci, ESB_CONFIG_REG, 0x0003);
396
397 /* Check that the WDT isn't already locked */
398 pci_read_config_byte(esb_pci, ESB_LOCK_REG, &val1);
399 if (val1 & ESB_WDT_LOCK)
400 pr_warn("nowayout already set\n");
401
402 /* Set the timer to watchdog mode and disable it for now */
403 pci_write_config_byte(esb_pci, ESB_LOCK_REG, 0x00);
404
405 /* Check if the watchdog was previously triggered */
406 esb_unlock_registers();
407 val2 = readw(ESB_RELOAD_REG);
408 if (val2 & ESB_WDT_TIMEOUT)
409 triggered = WDIOF_CARDRESET;
410
411 /* Reset WDT_TIMEOUT flag and timers */
412 esb_unlock_registers();
413 writew((ESB_WDT_TIMEOUT | ESB_WDT_RELOAD), ESB_RELOAD_REG);
414
415 /* And set the correct timeout value */
416 esb_timer_set_heartbeat(heartbeat);
417 }
418
esb_probe(struct pci_dev * pdev,const struct pci_device_id * ent)419 static int __devinit esb_probe(struct pci_dev *pdev,
420 const struct pci_device_id *ent)
421 {
422 int ret;
423
424 cards_found++;
425 if (cards_found == 1)
426 pr_info("Intel 6300ESB WatchDog Timer Driver v%s\n",
427 ESB_VERSION);
428
429 if (cards_found > 1) {
430 pr_err("This driver only supports 1 device\n");
431 return -ENODEV;
432 }
433
434 /* Check whether or not the hardware watchdog is there */
435 if (!esb_getdevice(pdev) || esb_pci == NULL)
436 return -ENODEV;
437
438 /* Check that the heartbeat value is within it's range;
439 if not reset to the default */
440 if (heartbeat < 0x1 || heartbeat > 2 * 0x03ff) {
441 heartbeat = WATCHDOG_HEARTBEAT;
442 pr_info("heartbeat value must be 1<heartbeat<2046, using %d\n",
443 heartbeat);
444 }
445
446 /* Initialize the watchdog and make sure it does not run */
447 esb_initdevice();
448
449 /* Register the watchdog so that userspace has access to it */
450 ret = misc_register(&esb_miscdev);
451 if (ret != 0) {
452 pr_err("cannot register miscdev on minor=%d (err=%d)\n",
453 WATCHDOG_MINOR, ret);
454 goto err_unmap;
455 }
456 pr_info("initialized (0x%p). heartbeat=%d sec (nowayout=%d)\n",
457 BASEADDR, heartbeat, nowayout);
458 return 0;
459
460 err_unmap:
461 iounmap(BASEADDR);
462 pci_release_region(esb_pci, 0);
463 pci_disable_device(esb_pci);
464 esb_pci = NULL;
465 return ret;
466 }
467
esb_remove(struct pci_dev * pdev)468 static void __devexit esb_remove(struct pci_dev *pdev)
469 {
470 /* Stop the timer before we leave */
471 if (!nowayout)
472 esb_timer_stop();
473
474 /* Deregister */
475 misc_deregister(&esb_miscdev);
476 iounmap(BASEADDR);
477 pci_release_region(esb_pci, 0);
478 pci_disable_device(esb_pci);
479 esb_pci = NULL;
480 }
481
esb_shutdown(struct pci_dev * pdev)482 static void esb_shutdown(struct pci_dev *pdev)
483 {
484 esb_timer_stop();
485 }
486
487 static struct pci_driver esb_driver = {
488 .name = ESB_MODULE_NAME,
489 .id_table = esb_pci_tbl,
490 .probe = esb_probe,
491 .remove = __devexit_p(esb_remove),
492 .shutdown = esb_shutdown,
493 };
494
watchdog_init(void)495 static int __init watchdog_init(void)
496 {
497 return pci_register_driver(&esb_driver);
498 }
499
watchdog_cleanup(void)500 static void __exit watchdog_cleanup(void)
501 {
502 pci_unregister_driver(&esb_driver);
503 pr_info("Watchdog Module Unloaded\n");
504 }
505
506 module_init(watchdog_init);
507 module_exit(watchdog_cleanup);
508
509 MODULE_AUTHOR("Ross Biro and David Härdeman");
510 MODULE_DESCRIPTION("Watchdog driver for Intel 6300ESB chipsets");
511 MODULE_LICENSE("GPL");
512 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
513