IB/uverbs: Fix reference counting usage of event files
[linux/fpc-iii.git] / drivers / watchdog / i6300esb.c
blobd7befd58b391a98cf074be706f3230b9e7c26d01
1 /*
2 * i6300esb: Watchdog timer driver for Intel 6300ESB chipset
4 * (c) Copyright 2004 Google Inc.
5 * (c) Copyright 2005 David Härdeman <david@2gen.com>
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.
12 * based on i810-tco.c which is in turn based on softdog.c
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
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
27 * Includes, defines, variables, module parameters, ...
30 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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/pci.h>
40 #include <linux/ioport.h>
41 #include <linux/uaccess.h>
42 #include <linux/io.h>
44 /* Module and version information */
45 #define ESB_VERSION "0.05"
46 #define ESB_MODULE_NAME "i6300ESB timer"
47 #define ESB_DRIVER_NAME ESB_MODULE_NAME ", v" ESB_VERSION
49 /* PCI configuration registers */
50 #define ESB_CONFIG_REG 0x60 /* Config register */
51 #define ESB_LOCK_REG 0x68 /* WDT lock register */
53 /* Memory mapped registers */
54 #define ESB_TIMER1_REG (BASEADDR + 0x00)/* Timer1 value after each reset */
55 #define ESB_TIMER2_REG (BASEADDR + 0x04)/* Timer2 value after each reset */
56 #define ESB_GINTSR_REG (BASEADDR + 0x08)/* General Interrupt Status Register */
57 #define ESB_RELOAD_REG (BASEADDR + 0x0c)/* Reload register */
59 /* Lock register bits */
60 #define ESB_WDT_FUNC (0x01 << 2) /* Watchdog functionality */
61 #define ESB_WDT_ENABLE (0x01 << 1) /* Enable WDT */
62 #define ESB_WDT_LOCK (0x01 << 0) /* Lock (nowayout) */
64 /* Config register bits */
65 #define ESB_WDT_REBOOT (0x01 << 5) /* Enable reboot on timeout */
66 #define ESB_WDT_FREQ (0x01 << 2) /* Decrement frequency */
67 #define ESB_WDT_INTTYPE (0x03 << 0) /* Interrupt type on timer1 timeout */
69 /* Reload register bits */
70 #define ESB_WDT_TIMEOUT (0x01 << 9) /* Watchdog timed out */
71 #define ESB_WDT_RELOAD (0x01 << 8) /* prevent timeout */
73 /* Magic constants */
74 #define ESB_UNLOCK1 0x80 /* Step 1 to unlock reset registers */
75 #define ESB_UNLOCK2 0x86 /* Step 2 to unlock reset registers */
77 /* internal variables */
78 static void __iomem *BASEADDR;
79 static DEFINE_SPINLOCK(esb_lock); /* Guards the hardware */
80 static unsigned long timer_alive;
81 static struct pci_dev *esb_pci;
82 static unsigned short triggered; /* The status of the watchdog upon boot */
83 static char esb_expect_close;
85 /* We can only use 1 card due to the /dev/watchdog restriction */
86 static int cards_found;
88 /* module parameters */
89 /* 30 sec default heartbeat (1 < heartbeat < 2*1023) */
90 #define WATCHDOG_HEARTBEAT 30
91 static int heartbeat = WATCHDOG_HEARTBEAT; /* in seconds */
92 module_param(heartbeat, int, 0);
93 MODULE_PARM_DESC(heartbeat,
94 "Watchdog heartbeat in seconds. (1<heartbeat<2046, default="
95 __MODULE_STRING(WATCHDOG_HEARTBEAT) ")");
97 static bool nowayout = WATCHDOG_NOWAYOUT;
98 module_param(nowayout, bool, 0);
99 MODULE_PARM_DESC(nowayout,
100 "Watchdog cannot be stopped once started (default="
101 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
104 * Some i6300ESB specific functions
108 * Prepare for reloading the timer by unlocking the proper registers.
109 * This is performed by first writing 0x80 followed by 0x86 to the
110 * reload register. After this the appropriate registers can be written
111 * to once before they need to be unlocked again.
113 static inline void esb_unlock_registers(void)
115 writew(ESB_UNLOCK1, ESB_RELOAD_REG);
116 writew(ESB_UNLOCK2, ESB_RELOAD_REG);
119 static int esb_timer_start(void)
121 u8 val;
123 spin_lock(&esb_lock);
124 esb_unlock_registers();
125 writew(ESB_WDT_RELOAD, ESB_RELOAD_REG);
126 /* Enable or Enable + Lock? */
127 val = ESB_WDT_ENABLE | (nowayout ? ESB_WDT_LOCK : 0x00);
128 pci_write_config_byte(esb_pci, ESB_LOCK_REG, val);
129 spin_unlock(&esb_lock);
130 return 0;
133 static int esb_timer_stop(void)
135 u8 val;
137 spin_lock(&esb_lock);
138 /* First, reset timers as suggested by the docs */
139 esb_unlock_registers();
140 writew(ESB_WDT_RELOAD, ESB_RELOAD_REG);
141 /* Then disable the WDT */
142 pci_write_config_byte(esb_pci, ESB_LOCK_REG, 0x0);
143 pci_read_config_byte(esb_pci, ESB_LOCK_REG, &val);
144 spin_unlock(&esb_lock);
146 /* Returns 0 if the timer was disabled, non-zero otherwise */
147 return val & ESB_WDT_ENABLE;
150 static void esb_timer_keepalive(void)
152 spin_lock(&esb_lock);
153 esb_unlock_registers();
154 writew(ESB_WDT_RELOAD, ESB_RELOAD_REG);
155 /* FIXME: Do we need to flush anything here? */
156 spin_unlock(&esb_lock);
159 static int esb_timer_set_heartbeat(int time)
161 u32 val;
163 if (time < 0x1 || time > (2 * 0x03ff))
164 return -EINVAL;
166 spin_lock(&esb_lock);
168 /* We shift by 9, so if we are passed a value of 1 sec,
169 * val will be 1 << 9 = 512, then write that to two
170 * timers => 2 * 512 = 1024 (which is decremented at 1KHz)
172 val = time << 9;
174 /* Write timer 1 */
175 esb_unlock_registers();
176 writel(val, ESB_TIMER1_REG);
178 /* Write timer 2 */
179 esb_unlock_registers();
180 writel(val, ESB_TIMER2_REG);
182 /* Reload */
183 esb_unlock_registers();
184 writew(ESB_WDT_RELOAD, ESB_RELOAD_REG);
186 /* FIXME: Do we need to flush everything out? */
188 /* Done */
189 heartbeat = time;
190 spin_unlock(&esb_lock);
191 return 0;
195 * /dev/watchdog handling
198 static int esb_open(struct inode *inode, struct file *file)
200 /* /dev/watchdog can only be opened once */
201 if (test_and_set_bit(0, &timer_alive))
202 return -EBUSY;
204 /* Reload and activate timer */
205 esb_timer_start();
207 return nonseekable_open(inode, file);
210 static int esb_release(struct inode *inode, struct file *file)
212 /* Shut off the timer. */
213 if (esb_expect_close == 42)
214 esb_timer_stop();
215 else {
216 pr_crit("Unexpected close, not stopping watchdog!\n");
217 esb_timer_keepalive();
219 clear_bit(0, &timer_alive);
220 esb_expect_close = 0;
221 return 0;
224 static ssize_t esb_write(struct file *file, const char __user *data,
225 size_t len, loff_t *ppos)
227 /* See if we got the magic character 'V' and reload the timer */
228 if (len) {
229 if (!nowayout) {
230 size_t i;
232 /* note: just in case someone wrote the magic character
233 * five months ago... */
234 esb_expect_close = 0;
236 /* scan to see whether or not we got the
237 * 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;
247 /* someone wrote to us, we should reload the timer */
248 esb_timer_keepalive();
250 return len;
253 static long esb_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
255 int new_options, retval = -EINVAL;
256 int new_heartbeat;
257 void __user *argp = (void __user *)arg;
258 int __user *p = argp;
259 static const struct watchdog_info ident = {
260 .options = WDIOF_SETTIMEOUT |
261 WDIOF_KEEPALIVEPING |
262 WDIOF_MAGICCLOSE,
263 .firmware_version = 0,
264 .identity = ESB_MODULE_NAME,
267 switch (cmd) {
268 case WDIOC_GETSUPPORT:
269 return copy_to_user(argp, &ident,
270 sizeof(ident)) ? -EFAULT : 0;
272 case WDIOC_GETSTATUS:
273 return put_user(0, p);
275 case WDIOC_GETBOOTSTATUS:
276 return put_user(triggered, p);
278 case WDIOC_SETOPTIONS:
280 if (get_user(new_options, p))
281 return -EFAULT;
283 if (new_options & WDIOS_DISABLECARD) {
284 esb_timer_stop();
285 retval = 0;
288 if (new_options & WDIOS_ENABLECARD) {
289 esb_timer_start();
290 retval = 0;
292 return retval;
294 case WDIOC_KEEPALIVE:
295 esb_timer_keepalive();
296 return 0;
298 case WDIOC_SETTIMEOUT:
300 if (get_user(new_heartbeat, p))
301 return -EFAULT;
302 if (esb_timer_set_heartbeat(new_heartbeat))
303 return -EINVAL;
304 esb_timer_keepalive();
305 /* Fall */
307 case WDIOC_GETTIMEOUT:
308 return put_user(heartbeat, p);
309 default:
310 return -ENOTTY;
315 * Kernel Interfaces
318 static const struct file_operations esb_fops = {
319 .owner = THIS_MODULE,
320 .llseek = no_llseek,
321 .write = esb_write,
322 .unlocked_ioctl = esb_ioctl,
323 .open = esb_open,
324 .release = esb_release,
327 static struct miscdevice esb_miscdev = {
328 .minor = WATCHDOG_MINOR,
329 .name = "watchdog",
330 .fops = &esb_fops,
334 * Data for PCI driver interface
336 static const struct pci_device_id esb_pci_tbl[] = {
337 { PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_ESB_9), },
338 { 0, }, /* End of list */
340 MODULE_DEVICE_TABLE(pci, esb_pci_tbl);
343 * Init & exit routines
346 static unsigned char esb_getdevice(struct pci_dev *pdev)
348 if (pci_enable_device(pdev)) {
349 pr_err("failed to enable device\n");
350 goto err_devput;
353 if (pci_request_region(pdev, 0, ESB_MODULE_NAME)) {
354 pr_err("failed to request region\n");
355 goto err_disable;
358 BASEADDR = pci_ioremap_bar(pdev, 0);
359 if (BASEADDR == NULL) {
360 /* Something's wrong here, BASEADDR has to be set */
361 pr_err("failed to get BASEADDR\n");
362 goto err_release;
365 /* Done */
366 esb_pci = pdev;
367 return 1;
369 err_release:
370 pci_release_region(pdev, 0);
371 err_disable:
372 pci_disable_device(pdev);
373 err_devput:
374 return 0;
377 static void esb_initdevice(void)
379 u8 val1;
380 u16 val2;
383 * Config register:
384 * Bit 5 : 0 = Enable WDT_OUTPUT
385 * Bit 2 : 0 = set the timer frequency to the PCI clock
386 * divided by 2^15 (approx 1KHz).
387 * Bits 1:0 : 11 = WDT_INT_TYPE Disabled.
388 * The watchdog has two timers, it can be setup so that the
389 * expiry of timer1 results in an interrupt and the expiry of
390 * timer2 results in a reboot. We set it to not generate
391 * any interrupts as there is not much we can do with it
392 * right now.
394 pci_write_config_word(esb_pci, ESB_CONFIG_REG, 0x0003);
396 /* Check that the WDT isn't already locked */
397 pci_read_config_byte(esb_pci, ESB_LOCK_REG, &val1);
398 if (val1 & ESB_WDT_LOCK)
399 pr_warn("nowayout already set\n");
401 /* Set the timer to watchdog mode and disable it for now */
402 pci_write_config_byte(esb_pci, ESB_LOCK_REG, 0x00);
404 /* Check if the watchdog was previously triggered */
405 esb_unlock_registers();
406 val2 = readw(ESB_RELOAD_REG);
407 if (val2 & ESB_WDT_TIMEOUT)
408 triggered = WDIOF_CARDRESET;
410 /* Reset WDT_TIMEOUT flag and timers */
411 esb_unlock_registers();
412 writew((ESB_WDT_TIMEOUT | ESB_WDT_RELOAD), ESB_RELOAD_REG);
414 /* And set the correct timeout value */
415 esb_timer_set_heartbeat(heartbeat);
418 static int esb_probe(struct pci_dev *pdev,
419 const struct pci_device_id *ent)
421 int ret;
423 cards_found++;
424 if (cards_found == 1)
425 pr_info("Intel 6300ESB WatchDog Timer Driver v%s\n",
426 ESB_VERSION);
428 if (cards_found > 1) {
429 pr_err("This driver only supports 1 device\n");
430 return -ENODEV;
433 /* Check whether or not the hardware watchdog is there */
434 if (!esb_getdevice(pdev) || esb_pci == NULL)
435 return -ENODEV;
437 /* Check that the heartbeat value is within it's range;
438 if not reset to the default */
439 if (heartbeat < 0x1 || heartbeat > 2 * 0x03ff) {
440 heartbeat = WATCHDOG_HEARTBEAT;
441 pr_info("heartbeat value must be 1<heartbeat<2046, using %d\n",
442 heartbeat);
445 /* Initialize the watchdog and make sure it does not run */
446 esb_initdevice();
448 /* Register the watchdog so that userspace has access to it */
449 ret = misc_register(&esb_miscdev);
450 if (ret != 0) {
451 pr_err("cannot register miscdev on minor=%d (err=%d)\n",
452 WATCHDOG_MINOR, ret);
453 goto err_unmap;
455 pr_info("initialized (0x%p). heartbeat=%d sec (nowayout=%d)\n",
456 BASEADDR, heartbeat, nowayout);
457 return 0;
459 err_unmap:
460 iounmap(BASEADDR);
461 pci_release_region(esb_pci, 0);
462 pci_disable_device(esb_pci);
463 esb_pci = NULL;
464 return ret;
467 static void esb_remove(struct pci_dev *pdev)
469 /* Stop the timer before we leave */
470 if (!nowayout)
471 esb_timer_stop();
473 /* Deregister */
474 misc_deregister(&esb_miscdev);
475 iounmap(BASEADDR);
476 pci_release_region(esb_pci, 0);
477 pci_disable_device(esb_pci);
478 esb_pci = NULL;
481 static void esb_shutdown(struct pci_dev *pdev)
483 esb_timer_stop();
486 static struct pci_driver esb_driver = {
487 .name = ESB_MODULE_NAME,
488 .id_table = esb_pci_tbl,
489 .probe = esb_probe,
490 .remove = esb_remove,
491 .shutdown = esb_shutdown,
494 module_pci_driver(esb_driver);
496 MODULE_AUTHOR("Ross Biro and David Härdeman");
497 MODULE_DESCRIPTION("Watchdog driver for Intel 6300ESB chipsets");
498 MODULE_LICENSE("GPL");