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David Hardemancc90ef02005-08-17 09:07:44 +02001/*
David Hardemanabda5c82005-09-01 22:34:53 +02002 * i6300esb: Watchdog timer driver for Intel 6300ESB chipset
David Hardemancc90ef02005-08-17 09:07:44 +02003 *
4 * (c) Copyright 2004 Google Inc.
David Hardemanabda5c82005-09-01 22:34:53 +02005 * (c) Copyright 2005 David Härdeman <david@2gen.com>
David Hardemancc90ef02005-08-17 09:07:44 +02006 *
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 *
David Hardemanabda5c82005-09-01 22:34:53 +020012 * based on i810-tco.c which is in turn based on softdog.c
David Hardemancc90ef02005-08-17 09:07:44 +020013 *
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 300641-003
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#include <linux/module.h>
31#include <linux/types.h>
32#include <linux/kernel.h>
33#include <linux/fs.h>
34#include <linux/mm.h>
35#include <linux/miscdevice.h>
36#include <linux/watchdog.h>
37#include <linux/reboot.h>
38#include <linux/init.h>
39#include <linux/pci.h>
40#include <linux/ioport.h>
41
42#include <asm/uaccess.h>
43#include <asm/io.h>
44
David Hardemancc90ef02005-08-17 09:07:44 +020045/* Module and version information */
46#define ESB_VERSION "0.03"
47#define ESB_MODULE_NAME "i6300ESB timer"
48#define ESB_DRIVER_NAME ESB_MODULE_NAME ", v" ESB_VERSION
49#define PFX ESB_MODULE_NAME ": "
50
David Hardemanabda5c82005-09-01 22:34:53 +020051/* PCI configuration registers */
52#define ESB_CONFIG_REG 0x60 /* Config register */
53#define ESB_LOCK_REG 0x68 /* WDT lock register */
54
55/* Memory mapped registers */
56#define ESB_TIMER1_REG BASEADDR + 0x00 /* Timer1 value after each reset */
57#define ESB_TIMER2_REG BASEADDR + 0x04 /* Timer2 value after each reset */
58#define ESB_GINTSR_REG BASEADDR + 0x08 /* General Interrupt Status Register */
59#define ESB_RELOAD_REG BASEADDR + 0x0c /* Reload register */
60
61/* Lock register bits */
62#define ESB_WDT_FUNC ( 0x01 << 2 ) /* Watchdog functionality */
63#define ESB_WDT_ENABLE ( 0x01 << 1 ) /* Enable WDT */
64#define ESB_WDT_LOCK ( 0x01 << 0 ) /* Lock (nowayout) */
65
66/* Config register bits */
67#define ESB_WDT_REBOOT ( 0x01 << 5 ) /* Enable reboot on timeout */
68#define ESB_WDT_FREQ ( 0x01 << 2 ) /* Decrement frequency */
69#define ESB_WDT_INTTYPE ( 0x11 << 0 ) /* Interrupt type on timer1 timeout */
70
71/* Reload register bits */
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
David Hardemancc90ef02005-08-17 09:07:44 +020078/* internal variables */
79static void __iomem *BASEADDR;
80static spinlock_t esb_lock; /* Guards the hardware */
81static unsigned long timer_alive;
82static struct pci_dev *esb_pci;
83static unsigned short triggered; /* The status of the watchdog upon boot */
84static char esb_expect_close;
85
86/* module parameters */
87#define WATCHDOG_HEARTBEAT 30 /* 30 sec default heartbeat (1<heartbeat<2*1023) */
88static int heartbeat = WATCHDOG_HEARTBEAT; /* in seconds */
89module_param(heartbeat, int, 0);
90MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds. (1<heartbeat<2046, default=" __MODULE_STRING(WATCHDOG_HEARTBEAT) ")");
91
Naveen Gupta811f9992005-08-21 13:02:41 +020092static int nowayout = WATCHDOG_NOWAYOUT;
David Hardemancc90ef02005-08-17 09:07:44 +020093module_param(nowayout, int, 0);
94MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)");
95
96/*
97 * Some i6300ESB specific functions
98 */
99
100/*
101 * Prepare for reloading the timer by unlocking the proper registers.
102 * This is performed by first writing 0x80 followed by 0x86 to the
103 * reload register. After this the appropriate registers can be written
104 * to once before they need to be unlocked again.
105 */
106static inline void esb_unlock_registers(void) {
107 writeb(ESB_UNLOCK1, ESB_RELOAD_REG);
108 writeb(ESB_UNLOCK2, ESB_RELOAD_REG);
109}
110
111static void esb_timer_start(void)
112{
113 u8 val;
114
115 /* Enable or Enable + Lock? */
Naveen Gupta28562af2005-08-17 09:10:10 +0200116 val = 0x02 | (nowayout ? 0x01 : 0x00);
David Hardemancc90ef02005-08-17 09:07:44 +0200117
118 pci_write_config_byte(esb_pci, ESB_LOCK_REG, val);
119}
120
121static int esb_timer_stop(void)
122{
123 u8 val;
124
125 spin_lock(&esb_lock);
126 /* First, reset timers as suggested by the docs */
127 esb_unlock_registers();
Naveen Guptace2f50b2005-08-17 09:11:46 +0200128 writew(ESB_WDT_RELOAD, ESB_RELOAD_REG);
David Hardemancc90ef02005-08-17 09:07:44 +0200129 /* Then disable the WDT */
130 pci_write_config_byte(esb_pci, ESB_LOCK_REG, 0x0);
131 pci_read_config_byte(esb_pci, ESB_LOCK_REG, &val);
132 spin_unlock(&esb_lock);
133
134 /* Returns 0 if the timer was disabled, non-zero otherwise */
135 return (val & 0x01);
136}
137
138static void esb_timer_keepalive(void)
139{
140 spin_lock(&esb_lock);
141 esb_unlock_registers();
Naveen Guptace2f50b2005-08-17 09:11:46 +0200142 writew(ESB_WDT_RELOAD, ESB_RELOAD_REG);
David Hardemancc90ef02005-08-17 09:07:44 +0200143 /* FIXME: Do we need to flush anything here? */
144 spin_unlock(&esb_lock);
145}
146
147static int esb_timer_set_heartbeat(int time)
148{
149 u32 val;
150
151 if (time < 0x1 || time > (2 * 0x03ff))
152 return -EINVAL;
153
154 spin_lock(&esb_lock);
155
156 /* We shift by 9, so if we are passed a value of 1 sec,
157 * val will be 1 << 9 = 512, then write that to two
158 * timers => 2 * 512 = 1024 (which is decremented at 1KHz)
159 */
160 val = time << 9;
161
162 /* Write timer 1 */
163 esb_unlock_registers();
164 writel(val, ESB_TIMER1_REG);
165
166 /* Write timer 2 */
167 esb_unlock_registers();
168 writel(val, ESB_TIMER2_REG);
169
170 /* Reload */
171 esb_unlock_registers();
Naveen Guptace2f50b2005-08-17 09:11:46 +0200172 writew(ESB_WDT_RELOAD, ESB_RELOAD_REG);
David Hardemancc90ef02005-08-17 09:07:44 +0200173
174 /* FIXME: Do we need to flush everything out? */
175
176 /* Done */
177 heartbeat = time;
178 spin_unlock(&esb_lock);
179 return 0;
180}
181
182static int esb_timer_read (void)
183{
184 u32 count;
185
186 /* This isn't documented, and doesn't take into
187 * acount which stage is running, but it looks
188 * like a 20 bit count down, so we might as well report it.
189 */
190 pci_read_config_dword(esb_pci, 0x64, &count);
191 return (int)count;
192}
193
194/*
195 * /dev/watchdog handling
196 */
197
198static int esb_open (struct inode *inode, struct file *file)
199{
200 /* /dev/watchdog can only be opened once */
201 if (test_and_set_bit(0, &timer_alive))
202 return -EBUSY;
203
204 /* Reload and activate timer */
205 esb_timer_keepalive ();
206 esb_timer_start ();
207
208 return nonseekable_open(inode, file);
209}
210
211static 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 printk(KERN_CRIT PFX "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
225static 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 magic character */
238 for (i = 0; i != len; i++) {
239 char c;
240 if(get_user(c, data+i))
241 return -EFAULT;
242 if (c == 'V')
243 esb_expect_close = 42;
244 }
245 }
246
247 /* someone wrote to us, we should reload the timer */
248 esb_timer_keepalive ();
249 }
250 return len;
251}
252
253static int esb_ioctl (struct inode *inode, struct file *file,
254 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 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 (esb_timer_read(), p);
275
276 case WDIOC_GETBOOTSTATUS:
277 return put_user (triggered, p);
278
279 case WDIOC_KEEPALIVE:
280 esb_timer_keepalive ();
281 return 0;
282
283 case WDIOC_SETOPTIONS:
284 {
285 if (get_user (new_options, p))
286 return -EFAULT;
287
288 if (new_options & WDIOS_DISABLECARD) {
289 esb_timer_stop ();
290 retval = 0;
291 }
292
293 if (new_options & WDIOS_ENABLECARD) {
294 esb_timer_keepalive ();
295 esb_timer_start ();
296 retval = 0;
297 }
298
299 return retval;
300 }
301
302 case WDIOC_SETTIMEOUT:
303 {
304 if (get_user(new_heartbeat, p))
305 return -EFAULT;
306
307 if (esb_timer_set_heartbeat(new_heartbeat))
308 return -EINVAL;
309
310 esb_timer_keepalive ();
311 /* Fall */
312 }
313
314 case WDIOC_GETTIMEOUT:
315 return put_user(heartbeat, p);
316
317 default:
318 return -ENOIOCTLCMD;
319 }
320}
321
322/*
323 * Notify system
324 */
325
326static int esb_notify_sys (struct notifier_block *this, unsigned long code, void *unused)
327{
328 if (code==SYS_DOWN || code==SYS_HALT) {
329 /* Turn the WDT off */
330 esb_timer_stop ();
331 }
332
333 return NOTIFY_DONE;
334}
335
336/*
337 * Kernel Interfaces
338 */
339
340static struct file_operations esb_fops = {
341 .owner = THIS_MODULE,
342 .llseek = no_llseek,
343 .write = esb_write,
344 .ioctl = esb_ioctl,
345 .open = esb_open,
346 .release = esb_release,
347};
348
349static struct miscdevice esb_miscdev = {
350 .minor = WATCHDOG_MINOR,
351 .name = "watchdog",
352 .fops = &esb_fops,
353};
354
355static struct notifier_block esb_notifier = {
356 .notifier_call = esb_notify_sys,
357};
358
359/*
360 * Data for PCI driver interface
361 *
362 * This data only exists for exporting the supported
363 * PCI ids via MODULE_DEVICE_TABLE. We do not actually
364 * register a pci_driver, because someone else might one day
365 * want to register another driver on the same PCI id.
366 */
367static struct pci_device_id esb_pci_tbl[] = {
Jiri Slabybb5dc362005-08-22 09:05:03 +0200368 { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_ESB_9), },
David Hardemancc90ef02005-08-17 09:07:44 +0200369 { 0, }, /* End of list */
370};
371MODULE_DEVICE_TABLE (pci, esb_pci_tbl);
372
373/*
374 * Init & exit routines
375 */
376
377static unsigned char __init esb_getdevice (void)
378{
379 u8 val1;
380 unsigned short val2;
381
382 struct pci_dev *dev = NULL;
383 /*
384 * Find the PCI device
385 */
386
Naveen Gupta811f9992005-08-21 13:02:41 +0200387 for_each_pci_dev(dev) {
Jiri Slabybb5dc362005-08-22 09:05:03 +0200388 if (pci_match_id(esb_pci_tbl, dev)) {
David Hardemancc90ef02005-08-17 09:07:44 +0200389 esb_pci = dev;
390 break;
391 }
Naveen Gupta811f9992005-08-21 13:02:41 +0200392 }
David Hardemancc90ef02005-08-17 09:07:44 +0200393
394 if (esb_pci) {
395 if (pci_enable_device(esb_pci)) {
396 printk (KERN_ERR PFX "failed to enable device\n");
Naveen Gupta811f9992005-08-21 13:02:41 +0200397 goto err_devput;
David Hardemancc90ef02005-08-17 09:07:44 +0200398 }
399
400 if (pci_request_region(esb_pci, 0, ESB_MODULE_NAME)) {
401 printk (KERN_ERR PFX "failed to request region\n");
402 goto err_disable;
403 }
404
405 BASEADDR = ioremap(pci_resource_start(esb_pci, 0),
406 pci_resource_len(esb_pci, 0));
407 if (BASEADDR == NULL) {
408 /* Something's wrong here, BASEADDR has to be set */
409 printk (KERN_ERR PFX "failed to get BASEADDR\n");
410 goto err_release;
411 }
412
413 /*
414 * The watchdog has two timers, it can be setup so that the
415 * expiry of timer1 results in an interrupt and the expiry of
416 * timer2 results in a reboot. We set it to not generate
417 * any interrupts as there is not much we can do with it
418 * right now.
419 *
420 * We also enable reboots and set the timer frequency to
421 * the PCI clock divided by 2^15 (approx 1KHz).
422 */
423 pci_write_config_word(esb_pci, ESB_CONFIG_REG, 0x0003);
424
425 /* Check that the WDT isn't already locked */
426 pci_read_config_byte(esb_pci, ESB_LOCK_REG, &val1);
427 if (val1 & ESB_WDT_LOCK)
428 printk (KERN_WARNING PFX "nowayout already set\n");
429
430 /* Set the timer to watchdog mode and disable it for now */
431 pci_write_config_byte(esb_pci, ESB_LOCK_REG, 0x00);
432
433 /* Check if the watchdog was previously triggered */
434 esb_unlock_registers();
435 val2 = readw(ESB_RELOAD_REG);
436 triggered = (val2 & (0x01 << 9) >> 9);
437
438 /* Reset trigger flag and timers */
439 esb_unlock_registers();
440 writew((0x11 << 8), ESB_RELOAD_REG);
441
442 /* Done */
443 return 1;
444
445err_release:
446 pci_release_region(esb_pci, 0);
447err_disable:
448 pci_disable_device(esb_pci);
Naveen Gupta811f9992005-08-21 13:02:41 +0200449err_devput:
Jiri Slabyc69af032005-08-17 09:09:13 +0200450 pci_dev_put(esb_pci);
David Hardemancc90ef02005-08-17 09:07:44 +0200451 }
David Hardemancc90ef02005-08-17 09:07:44 +0200452 return 0;
453}
454
455static int __init watchdog_init (void)
456{
457 int ret;
458
459 spin_lock_init(&esb_lock);
460
461 /* Check whether or not the hardware watchdog is there */
462 if (!esb_getdevice () || esb_pci == NULL)
463 return -ENODEV;
464
465 /* Check that the heartbeat value is within it's range ; if not reset to the default */
466 if (esb_timer_set_heartbeat (heartbeat)) {
467 esb_timer_set_heartbeat (WATCHDOG_HEARTBEAT);
468 printk(KERN_INFO PFX "heartbeat value must be 1<heartbeat<2046, using %d\n",
469 heartbeat);
470 }
471
472 ret = register_reboot_notifier(&esb_notifier);
473 if (ret != 0) {
474 printk(KERN_ERR PFX "cannot register reboot notifier (err=%d)\n",
475 ret);
476 goto err_unmap;
477 }
478
479 ret = misc_register(&esb_miscdev);
480 if (ret != 0) {
481 printk(KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n",
482 WATCHDOG_MINOR, ret);
483 goto err_notifier;
484 }
485
486 esb_timer_stop ();
487
488 printk (KERN_INFO PFX "initialized (0x%p). heartbeat=%d sec (nowayout=%d)\n",
489 BASEADDR, heartbeat, nowayout);
490
491 return 0;
492
493err_notifier:
494 unregister_reboot_notifier(&esb_notifier);
495err_unmap:
496 iounmap(BASEADDR);
497/* err_release: */
498 pci_release_region(esb_pci, 0);
499/* err_disable: */
500 pci_disable_device(esb_pci);
Naveen Gupta811f9992005-08-21 13:02:41 +0200501/* err_devput: */
Jiri Slabyc69af032005-08-17 09:09:13 +0200502 pci_dev_put(esb_pci);
David Hardemancc90ef02005-08-17 09:07:44 +0200503 return ret;
504}
505
506static void __exit watchdog_cleanup (void)
507{
508 /* Stop the timer before we leave */
509 if (!nowayout)
510 esb_timer_stop ();
511
512 /* Deregister */
513 misc_deregister(&esb_miscdev);
514 unregister_reboot_notifier(&esb_notifier);
515 iounmap(BASEADDR);
516 pci_release_region(esb_pci, 0);
517 pci_disable_device(esb_pci);
Jiri Slabyc69af032005-08-17 09:09:13 +0200518 pci_dev_put(esb_pci);
David Hardemancc90ef02005-08-17 09:07:44 +0200519}
520
521module_init(watchdog_init);
522module_exit(watchdog_cleanup);
523
524MODULE_AUTHOR("Ross Biro and David Härdeman");
525MODULE_DESCRIPTION("Watchdog driver for Intel 6300ESB chipsets");
526MODULE_LICENSE("GPL");
527MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);