xref: /openbmc/linux/drivers/watchdog/pcwd_usb.c (revision 6dfcd296)
1 /*
2  *	Berkshire USB-PC Watchdog Card Driver
3  *
4  *	(c) Copyright 2004-2007 Wim Van Sebroeck <wim@iguana.be>.
5  *
6  *	Based on source code of the following authors:
7  *	  Ken Hollis <kenji@bitgate.com>,
8  *	  Alan Cox <alan@lxorguk.ukuu.org.uk>,
9  *	  Matt Domsch <Matt_Domsch@dell.com>,
10  *	  Rob Radez <rob@osinvestor.com>,
11  *	  Greg Kroah-Hartman <greg@kroah.com>
12  *
13  *	This program is free software; you can redistribute it and/or
14  *	modify it under the terms of the GNU General Public License
15  *	as published by the Free Software Foundation; either version
16  *	2 of the License, or (at your option) any later version.
17  *
18  *	Neither Wim Van Sebroeck nor Iguana vzw. admit liability nor
19  *	provide warranty for any of this software. This material is
20  *	provided "AS-IS" and at no charge.
21  *
22  *	Thanks also to Simon Machell at Berkshire Products Inc. for
23  *	providing the test hardware. More info is available at
24  *	http://www.berkprod.com/ or http://www.pcwatchdog.com/
25  */
26 
27 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
28 
29 #include <linux/module.h>	/* For module specific items */
30 #include <linux/moduleparam.h>	/* For new moduleparam's */
31 #include <linux/types.h>	/* For standard types (like size_t) */
32 #include <linux/errno.h>	/* For the -ENODEV/... values */
33 #include <linux/kernel.h>	/* For printk/panic/... */
34 #include <linux/delay.h>	/* For mdelay function */
35 #include <linux/miscdevice.h>	/* For struct miscdevice */
36 #include <linux/watchdog.h>	/* For the watchdog specific items */
37 #include <linux/notifier.h>	/* For notifier support */
38 #include <linux/reboot.h>	/* For reboot_notifier stuff */
39 #include <linux/init.h>		/* For __init/__exit/... */
40 #include <linux/fs.h>		/* For file operations */
41 #include <linux/usb.h>		/* For USB functions */
42 #include <linux/slab.h>		/* For kmalloc, ... */
43 #include <linux/mutex.h>	/* For mutex locking */
44 #include <linux/hid.h>		/* For HID_REQ_SET_REPORT & HID_DT_REPORT */
45 #include <linux/uaccess.h>	/* For copy_to_user/put_user/... */
46 
47 
48 /* Module and Version Information */
49 #define DRIVER_VERSION "1.02"
50 #define DRIVER_AUTHOR "Wim Van Sebroeck <wim@iguana.be>"
51 #define DRIVER_DESC "Berkshire USB-PC Watchdog driver"
52 #define DRIVER_LICENSE "GPL"
53 #define DRIVER_NAME "pcwd_usb"
54 
55 MODULE_AUTHOR(DRIVER_AUTHOR);
56 MODULE_DESCRIPTION(DRIVER_DESC);
57 MODULE_LICENSE(DRIVER_LICENSE);
58 
59 #define WATCHDOG_HEARTBEAT 0	/* default heartbeat =
60 						delay-time from dip-switches */
61 static int heartbeat = WATCHDOG_HEARTBEAT;
62 module_param(heartbeat, int, 0);
63 MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds. "
64 	"(0<heartbeat<65536 or 0=delay-time from dip-switches, default="
65 				__MODULE_STRING(WATCHDOG_HEARTBEAT) ")");
66 
67 static bool nowayout = WATCHDOG_NOWAYOUT;
68 module_param(nowayout, bool, 0);
69 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
70 				__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
71 
72 /* The vendor and product id's for the USB-PC Watchdog card */
73 #define USB_PCWD_VENDOR_ID	0x0c98
74 #define USB_PCWD_PRODUCT_ID	0x1140
75 
76 /* table of devices that work with this driver */
77 static struct usb_device_id usb_pcwd_table[] = {
78 	{ USB_DEVICE(USB_PCWD_VENDOR_ID, USB_PCWD_PRODUCT_ID) },
79 	{ }					/* Terminating entry */
80 };
81 MODULE_DEVICE_TABLE(usb, usb_pcwd_table);
82 
83 /* according to documentation max. time to process a command for the USB
84  * watchdog card is 100 or 200 ms, so we give it 250 ms to do it's job */
85 #define USB_COMMAND_TIMEOUT	250
86 
87 /* Watchdog's internal commands */
88 #define CMD_READ_TEMP			0x02	/* Read Temperature;
89 							Re-trigger Watchdog */
90 #define CMD_TRIGGER			CMD_READ_TEMP
91 #define CMD_GET_STATUS			0x04	/* Get Status Information */
92 #define CMD_GET_FIRMWARE_VERSION	0x08	/* Get Firmware Version */
93 #define CMD_GET_DIP_SWITCH_SETTINGS	0x0c	/* Get Dip Switch Settings */
94 #define CMD_READ_WATCHDOG_TIMEOUT	0x18	/* Read Current Watchdog Time */
95 #define CMD_WRITE_WATCHDOG_TIMEOUT	0x19	/* Write Current WatchdogTime */
96 #define CMD_ENABLE_WATCHDOG		0x30	/* Enable / Disable Watchdog */
97 #define CMD_DISABLE_WATCHDOG		CMD_ENABLE_WATCHDOG
98 
99 /* Watchdog's Dip Switch heartbeat values */
100 static const int heartbeat_tbl[] = {
101 	5,	/* OFF-OFF-OFF	=  5 Sec  */
102 	10,	/* OFF-OFF-ON	= 10 Sec  */
103 	30,	/* OFF-ON-OFF	= 30 Sec  */
104 	60,	/* OFF-ON-ON	=  1 Min  */
105 	300,	/* ON-OFF-OFF	=  5 Min  */
106 	600,	/* ON-OFF-ON	= 10 Min  */
107 	1800,	/* ON-ON-OFF	= 30 Min  */
108 	3600,	/* ON-ON-ON	=  1 hour */
109 };
110 
111 /* We can only use 1 card due to the /dev/watchdog restriction */
112 static int cards_found;
113 
114 /* some internal variables */
115 static unsigned long is_active;
116 static char expect_release;
117 
118 /* Structure to hold all of our device specific stuff */
119 struct usb_pcwd_private {
120 	/* save off the usb device pointer */
121 	struct usb_device	*udev;
122 	/* the interface for this device */
123 	struct usb_interface	*interface;
124 
125 	/* the interface number used for cmd's */
126 	unsigned int		interface_number;
127 
128 	/* the buffer to intr data */
129 	unsigned char		*intr_buffer;
130 	/* the dma address for the intr buffer */
131 	dma_addr_t		intr_dma;
132 	/* the size of the intr buffer */
133 	size_t			intr_size;
134 	/* the urb used for the intr pipe */
135 	struct urb		*intr_urb;
136 
137 	/* The command that is reported back */
138 	unsigned char		cmd_command;
139 	/* The data MSB that is reported back */
140 	unsigned char		cmd_data_msb;
141 	/* The data LSB that is reported back */
142 	unsigned char		cmd_data_lsb;
143 	/* true if we received a report after a command */
144 	atomic_t		cmd_received;
145 
146 	/* Wether or not the device exists */
147 	int			exists;
148 	/* locks this structure */
149 	struct mutex		mtx;
150 };
151 static struct usb_pcwd_private *usb_pcwd_device;
152 
153 /* prevent races between open() and disconnect() */
154 static DEFINE_MUTEX(disconnect_mutex);
155 
156 /* local function prototypes */
157 static int usb_pcwd_probe(struct usb_interface *interface,
158 						const struct usb_device_id *id);
159 static void usb_pcwd_disconnect(struct usb_interface *interface);
160 
161 /* usb specific object needed to register this driver with the usb subsystem */
162 static struct usb_driver usb_pcwd_driver = {
163 	.name =		DRIVER_NAME,
164 	.probe =	usb_pcwd_probe,
165 	.disconnect =	usb_pcwd_disconnect,
166 	.id_table =	usb_pcwd_table,
167 };
168 
169 
170 static void usb_pcwd_intr_done(struct urb *urb)
171 {
172 	struct usb_pcwd_private *usb_pcwd =
173 				(struct usb_pcwd_private *)urb->context;
174 	unsigned char *data = usb_pcwd->intr_buffer;
175 	struct device *dev = &usb_pcwd->interface->dev;
176 	int retval;
177 
178 	switch (urb->status) {
179 	case 0:			/* success */
180 		break;
181 	case -ECONNRESET:	/* unlink */
182 	case -ENOENT:
183 	case -ESHUTDOWN:
184 		/* this urb is terminated, clean up */
185 		dev_dbg(dev, "%s - urb shutting down with status: %d",
186 			__func__, urb->status);
187 		return;
188 	/* -EPIPE:  should clear the halt */
189 	default:		/* error */
190 		dev_dbg(dev, "%s - nonzero urb status received: %d",
191 			__func__, urb->status);
192 		goto resubmit;
193 	}
194 
195 	dev_dbg(dev, "received following data cmd=0x%02x msb=0x%02x lsb=0x%02x",
196 		data[0], data[1], data[2]);
197 
198 	usb_pcwd->cmd_command  = data[0];
199 	usb_pcwd->cmd_data_msb = data[1];
200 	usb_pcwd->cmd_data_lsb = data[2];
201 
202 	/* notify anyone waiting that the cmd has finished */
203 	atomic_set(&usb_pcwd->cmd_received, 1);
204 
205 resubmit:
206 	retval = usb_submit_urb(urb, GFP_ATOMIC);
207 	if (retval)
208 		pr_err("can't resubmit intr, usb_submit_urb failed with result %d\n",
209 		       retval);
210 }
211 
212 static int usb_pcwd_send_command(struct usb_pcwd_private *usb_pcwd,
213 		unsigned char cmd, unsigned char *msb, unsigned char *lsb)
214 {
215 	int got_response, count;
216 	unsigned char *buf;
217 
218 	/* We will not send any commands if the USB PCWD device does
219 	 * not exist */
220 	if ((!usb_pcwd) || (!usb_pcwd->exists))
221 		return -1;
222 
223 	buf = kmalloc(6, GFP_KERNEL);
224 	if (buf == NULL)
225 		return 0;
226 
227 	/* The USB PC Watchdog uses a 6 byte report format.
228 	 * The board currently uses only 3 of the six bytes of the report. */
229 	buf[0] = cmd;			/* Byte 0 = CMD */
230 	buf[1] = *msb;			/* Byte 1 = Data MSB */
231 	buf[2] = *lsb;			/* Byte 2 = Data LSB */
232 	buf[3] = buf[4] = buf[5] = 0;	/* All other bytes not used */
233 
234 	dev_dbg(&usb_pcwd->interface->dev,
235 		"sending following data cmd=0x%02x msb=0x%02x lsb=0x%02x",
236 		buf[0], buf[1], buf[2]);
237 
238 	atomic_set(&usb_pcwd->cmd_received, 0);
239 
240 	if (usb_control_msg(usb_pcwd->udev, usb_sndctrlpipe(usb_pcwd->udev, 0),
241 			HID_REQ_SET_REPORT, HID_DT_REPORT,
242 			0x0200, usb_pcwd->interface_number, buf, 6,
243 			USB_COMMAND_TIMEOUT) != 6) {
244 		dev_dbg(&usb_pcwd->interface->dev,
245 			"usb_pcwd_send_command: error in usb_control_msg for cmd 0x%x 0x%x 0x%x\n",
246 			cmd, *msb, *lsb);
247 	}
248 	/* wait till the usb card processed the command,
249 	 * with a max. timeout of USB_COMMAND_TIMEOUT */
250 	got_response = 0;
251 	for (count = 0; (count < USB_COMMAND_TIMEOUT) && (!got_response);
252 								count++) {
253 		mdelay(1);
254 		if (atomic_read(&usb_pcwd->cmd_received))
255 			got_response = 1;
256 	}
257 
258 	if ((got_response) && (cmd == usb_pcwd->cmd_command)) {
259 		/* read back response */
260 		*msb = usb_pcwd->cmd_data_msb;
261 		*lsb = usb_pcwd->cmd_data_lsb;
262 	}
263 
264 	kfree(buf);
265 
266 	return got_response;
267 }
268 
269 static int usb_pcwd_start(struct usb_pcwd_private *usb_pcwd)
270 {
271 	unsigned char msb = 0x00;
272 	unsigned char lsb = 0x00;
273 	int retval;
274 
275 	/* Enable Watchdog */
276 	retval = usb_pcwd_send_command(usb_pcwd, CMD_ENABLE_WATCHDOG,
277 								&msb, &lsb);
278 
279 	if ((retval == 0) || (lsb == 0)) {
280 		pr_err("Card did not acknowledge enable attempt\n");
281 		return -1;
282 	}
283 
284 	return 0;
285 }
286 
287 static int usb_pcwd_stop(struct usb_pcwd_private *usb_pcwd)
288 {
289 	unsigned char msb = 0xA5;
290 	unsigned char lsb = 0xC3;
291 	int retval;
292 
293 	/* Disable Watchdog */
294 	retval = usb_pcwd_send_command(usb_pcwd, CMD_DISABLE_WATCHDOG,
295 								&msb, &lsb);
296 
297 	if ((retval == 0) || (lsb != 0)) {
298 		pr_err("Card did not acknowledge disable attempt\n");
299 		return -1;
300 	}
301 
302 	return 0;
303 }
304 
305 static int usb_pcwd_keepalive(struct usb_pcwd_private *usb_pcwd)
306 {
307 	unsigned char dummy;
308 
309 	/* Re-trigger Watchdog */
310 	usb_pcwd_send_command(usb_pcwd, CMD_TRIGGER, &dummy, &dummy);
311 
312 	return 0;
313 }
314 
315 static int usb_pcwd_set_heartbeat(struct usb_pcwd_private *usb_pcwd, int t)
316 {
317 	unsigned char msb = t / 256;
318 	unsigned char lsb = t % 256;
319 
320 	if ((t < 0x0001) || (t > 0xFFFF))
321 		return -EINVAL;
322 
323 	/* Write new heartbeat to watchdog */
324 	usb_pcwd_send_command(usb_pcwd, CMD_WRITE_WATCHDOG_TIMEOUT, &msb, &lsb);
325 
326 	heartbeat = t;
327 	return 0;
328 }
329 
330 static int usb_pcwd_get_temperature(struct usb_pcwd_private *usb_pcwd,
331 							int *temperature)
332 {
333 	unsigned char msb, lsb;
334 
335 	usb_pcwd_send_command(usb_pcwd, CMD_READ_TEMP, &msb, &lsb);
336 
337 	/*
338 	 * Convert celsius to fahrenheit, since this was
339 	 * the decided 'standard' for this return value.
340 	 */
341 	*temperature = (lsb * 9 / 5) + 32;
342 
343 	return 0;
344 }
345 
346 static int usb_pcwd_get_timeleft(struct usb_pcwd_private *usb_pcwd,
347 								int *time_left)
348 {
349 	unsigned char msb, lsb;
350 
351 	/* Read the time that's left before rebooting */
352 	/* Note: if the board is not yet armed then we will read 0xFFFF */
353 	usb_pcwd_send_command(usb_pcwd, CMD_READ_WATCHDOG_TIMEOUT, &msb, &lsb);
354 
355 	*time_left = (msb << 8) + lsb;
356 
357 	return 0;
358 }
359 
360 /*
361  *	/dev/watchdog handling
362  */
363 
364 static ssize_t usb_pcwd_write(struct file *file, const char __user *data,
365 						size_t len, loff_t *ppos)
366 {
367 	/* See if we got the magic character 'V' and reload the timer */
368 	if (len) {
369 		if (!nowayout) {
370 			size_t i;
371 
372 			/* note: just in case someone wrote the magic character
373 			 * five months ago... */
374 			expect_release = 0;
375 
376 			/* scan to see whether or not we got the
377 			 * magic character */
378 			for (i = 0; i != len; i++) {
379 				char c;
380 				if (get_user(c, data + i))
381 					return -EFAULT;
382 				if (c == 'V')
383 					expect_release = 42;
384 			}
385 		}
386 
387 		/* someone wrote to us, we should reload the timer */
388 		usb_pcwd_keepalive(usb_pcwd_device);
389 	}
390 	return len;
391 }
392 
393 static long usb_pcwd_ioctl(struct file *file, unsigned int cmd,
394 						unsigned long arg)
395 {
396 	void __user *argp = (void __user *)arg;
397 	int __user *p = argp;
398 	static const struct watchdog_info ident = {
399 		.options =		WDIOF_KEEPALIVEPING |
400 					WDIOF_SETTIMEOUT |
401 					WDIOF_MAGICCLOSE,
402 		.firmware_version =	1,
403 		.identity =		DRIVER_NAME,
404 	};
405 
406 	switch (cmd) {
407 	case WDIOC_GETSUPPORT:
408 		return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
409 
410 	case WDIOC_GETSTATUS:
411 	case WDIOC_GETBOOTSTATUS:
412 		return put_user(0, p);
413 
414 	case WDIOC_GETTEMP:
415 	{
416 		int temperature;
417 
418 		if (usb_pcwd_get_temperature(usb_pcwd_device, &temperature))
419 			return -EFAULT;
420 
421 		return put_user(temperature, p);
422 	}
423 
424 	case WDIOC_SETOPTIONS:
425 	{
426 		int new_options, retval = -EINVAL;
427 
428 		if (get_user(new_options, p))
429 			return -EFAULT;
430 
431 		if (new_options & WDIOS_DISABLECARD) {
432 			usb_pcwd_stop(usb_pcwd_device);
433 			retval = 0;
434 		}
435 
436 		if (new_options & WDIOS_ENABLECARD) {
437 			usb_pcwd_start(usb_pcwd_device);
438 			retval = 0;
439 		}
440 
441 		return retval;
442 	}
443 
444 	case WDIOC_KEEPALIVE:
445 		usb_pcwd_keepalive(usb_pcwd_device);
446 		return 0;
447 
448 	case WDIOC_SETTIMEOUT:
449 	{
450 		int new_heartbeat;
451 
452 		if (get_user(new_heartbeat, p))
453 			return -EFAULT;
454 
455 		if (usb_pcwd_set_heartbeat(usb_pcwd_device, new_heartbeat))
456 			return -EINVAL;
457 
458 		usb_pcwd_keepalive(usb_pcwd_device);
459 		/* Fall */
460 	}
461 
462 	case WDIOC_GETTIMEOUT:
463 		return put_user(heartbeat, p);
464 
465 	case WDIOC_GETTIMELEFT:
466 	{
467 		int time_left;
468 
469 		if (usb_pcwd_get_timeleft(usb_pcwd_device, &time_left))
470 			return -EFAULT;
471 
472 		return put_user(time_left, p);
473 	}
474 
475 	default:
476 		return -ENOTTY;
477 	}
478 }
479 
480 static int usb_pcwd_open(struct inode *inode, struct file *file)
481 {
482 	/* /dev/watchdog can only be opened once */
483 	if (test_and_set_bit(0, &is_active))
484 		return -EBUSY;
485 
486 	/* Activate */
487 	usb_pcwd_start(usb_pcwd_device);
488 	usb_pcwd_keepalive(usb_pcwd_device);
489 	return nonseekable_open(inode, file);
490 }
491 
492 static int usb_pcwd_release(struct inode *inode, struct file *file)
493 {
494 	/*
495 	 *      Shut off the timer.
496 	 */
497 	if (expect_release == 42) {
498 		usb_pcwd_stop(usb_pcwd_device);
499 	} else {
500 		pr_crit("Unexpected close, not stopping watchdog!\n");
501 		usb_pcwd_keepalive(usb_pcwd_device);
502 	}
503 	expect_release = 0;
504 	clear_bit(0, &is_active);
505 	return 0;
506 }
507 
508 /*
509  *	/dev/temperature handling
510  */
511 
512 static ssize_t usb_pcwd_temperature_read(struct file *file, char __user *data,
513 				size_t len, loff_t *ppos)
514 {
515 	int temperature;
516 
517 	if (usb_pcwd_get_temperature(usb_pcwd_device, &temperature))
518 		return -EFAULT;
519 
520 	if (copy_to_user(data, &temperature, 1))
521 		return -EFAULT;
522 
523 	return 1;
524 }
525 
526 static int usb_pcwd_temperature_open(struct inode *inode, struct file *file)
527 {
528 	return nonseekable_open(inode, file);
529 }
530 
531 static int usb_pcwd_temperature_release(struct inode *inode, struct file *file)
532 {
533 	return 0;
534 }
535 
536 /*
537  *	Notify system
538  */
539 
540 static int usb_pcwd_notify_sys(struct notifier_block *this, unsigned long code,
541 								void *unused)
542 {
543 	if (code == SYS_DOWN || code == SYS_HALT)
544 		usb_pcwd_stop(usb_pcwd_device);	/* Turn the WDT off */
545 
546 	return NOTIFY_DONE;
547 }
548 
549 /*
550  *	Kernel Interfaces
551  */
552 
553 static const struct file_operations usb_pcwd_fops = {
554 	.owner =	THIS_MODULE,
555 	.llseek =	no_llseek,
556 	.write =	usb_pcwd_write,
557 	.unlocked_ioctl = usb_pcwd_ioctl,
558 	.open =		usb_pcwd_open,
559 	.release =	usb_pcwd_release,
560 };
561 
562 static struct miscdevice usb_pcwd_miscdev = {
563 	.minor =	WATCHDOG_MINOR,
564 	.name =		"watchdog",
565 	.fops =		&usb_pcwd_fops,
566 };
567 
568 static const struct file_operations usb_pcwd_temperature_fops = {
569 	.owner =	THIS_MODULE,
570 	.llseek =	no_llseek,
571 	.read =		usb_pcwd_temperature_read,
572 	.open =		usb_pcwd_temperature_open,
573 	.release =	usb_pcwd_temperature_release,
574 };
575 
576 static struct miscdevice usb_pcwd_temperature_miscdev = {
577 	.minor =	TEMP_MINOR,
578 	.name =		"temperature",
579 	.fops =		&usb_pcwd_temperature_fops,
580 };
581 
582 static struct notifier_block usb_pcwd_notifier = {
583 	.notifier_call =	usb_pcwd_notify_sys,
584 };
585 
586 /**
587  *	usb_pcwd_delete
588  */
589 static inline void usb_pcwd_delete(struct usb_pcwd_private *usb_pcwd)
590 {
591 	usb_free_urb(usb_pcwd->intr_urb);
592 	if (usb_pcwd->intr_buffer != NULL)
593 		usb_free_coherent(usb_pcwd->udev, usb_pcwd->intr_size,
594 				  usb_pcwd->intr_buffer, usb_pcwd->intr_dma);
595 	kfree(usb_pcwd);
596 }
597 
598 /**
599  *	usb_pcwd_probe
600  *
601  *	Called by the usb core when a new device is connected that it thinks
602  *	this driver might be interested in.
603  */
604 static int usb_pcwd_probe(struct usb_interface *interface,
605 						const struct usb_device_id *id)
606 {
607 	struct usb_device *udev = interface_to_usbdev(interface);
608 	struct usb_host_interface *iface_desc;
609 	struct usb_endpoint_descriptor *endpoint;
610 	struct usb_pcwd_private *usb_pcwd = NULL;
611 	int pipe;
612 	int retval = -ENOMEM;
613 	int got_fw_rev;
614 	unsigned char fw_rev_major, fw_rev_minor;
615 	char fw_ver_str[20];
616 	unsigned char option_switches, dummy;
617 
618 	cards_found++;
619 	if (cards_found > 1) {
620 		pr_err("This driver only supports 1 device\n");
621 		return -ENODEV;
622 	}
623 
624 	/* get the active interface descriptor */
625 	iface_desc = interface->cur_altsetting;
626 
627 	/* check out that we have a HID device */
628 	if (!(iface_desc->desc.bInterfaceClass == USB_CLASS_HID)) {
629 		pr_err("The device isn't a Human Interface Device\n");
630 		return -ENODEV;
631 	}
632 
633 	/* check out the endpoint: it has to be Interrupt & IN */
634 	endpoint = &iface_desc->endpoint[0].desc;
635 
636 	if (!usb_endpoint_is_int_in(endpoint)) {
637 		/* we didn't find a Interrupt endpoint with direction IN */
638 		pr_err("Couldn't find an INTR & IN endpoint\n");
639 		return -ENODEV;
640 	}
641 
642 	/* get a handle to the interrupt data pipe */
643 	pipe = usb_rcvintpipe(udev, endpoint->bEndpointAddress);
644 
645 	/* allocate memory for our device and initialize it */
646 	usb_pcwd = kzalloc(sizeof(struct usb_pcwd_private), GFP_KERNEL);
647 	if (usb_pcwd == NULL)
648 		goto error;
649 
650 	usb_pcwd_device = usb_pcwd;
651 
652 	mutex_init(&usb_pcwd->mtx);
653 	usb_pcwd->udev = udev;
654 	usb_pcwd->interface = interface;
655 	usb_pcwd->interface_number = iface_desc->desc.bInterfaceNumber;
656 	usb_pcwd->intr_size = (le16_to_cpu(endpoint->wMaxPacketSize) > 8 ?
657 				le16_to_cpu(endpoint->wMaxPacketSize) : 8);
658 
659 	/* set up the memory buffer's */
660 	usb_pcwd->intr_buffer = usb_alloc_coherent(udev, usb_pcwd->intr_size,
661 					GFP_ATOMIC, &usb_pcwd->intr_dma);
662 	if (!usb_pcwd->intr_buffer) {
663 		pr_err("Out of memory\n");
664 		goto error;
665 	}
666 
667 	/* allocate the urb's */
668 	usb_pcwd->intr_urb = usb_alloc_urb(0, GFP_KERNEL);
669 	if (!usb_pcwd->intr_urb)
670 		goto error;
671 
672 	/* initialise the intr urb's */
673 	usb_fill_int_urb(usb_pcwd->intr_urb, udev, pipe,
674 			usb_pcwd->intr_buffer, usb_pcwd->intr_size,
675 			usb_pcwd_intr_done, usb_pcwd, endpoint->bInterval);
676 	usb_pcwd->intr_urb->transfer_dma = usb_pcwd->intr_dma;
677 	usb_pcwd->intr_urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
678 
679 	/* register our interrupt URB with the USB system */
680 	if (usb_submit_urb(usb_pcwd->intr_urb, GFP_KERNEL)) {
681 		pr_err("Problem registering interrupt URB\n");
682 		retval = -EIO; /* failure */
683 		goto error;
684 	}
685 
686 	/* The device exists and can be communicated with */
687 	usb_pcwd->exists = 1;
688 
689 	/* disable card */
690 	usb_pcwd_stop(usb_pcwd);
691 
692 	/* Get the Firmware Version */
693 	got_fw_rev = usb_pcwd_send_command(usb_pcwd, CMD_GET_FIRMWARE_VERSION,
694 						&fw_rev_major, &fw_rev_minor);
695 	if (got_fw_rev)
696 		sprintf(fw_ver_str, "%u.%02u", fw_rev_major, fw_rev_minor);
697 	else
698 		sprintf(fw_ver_str, "<card no answer>");
699 
700 	pr_info("Found card (Firmware: %s) with temp option\n", fw_ver_str);
701 
702 	/* Get switch settings */
703 	usb_pcwd_send_command(usb_pcwd, CMD_GET_DIP_SWITCH_SETTINGS, &dummy,
704 							&option_switches);
705 
706 	pr_info("Option switches (0x%02x): Temperature Reset Enable=%s, Power On Delay=%s\n",
707 		option_switches,
708 		((option_switches & 0x10) ? "ON" : "OFF"),
709 		((option_switches & 0x08) ? "ON" : "OFF"));
710 
711 	/* If heartbeat = 0 then we use the heartbeat from the dip-switches */
712 	if (heartbeat == 0)
713 		heartbeat = heartbeat_tbl[(option_switches & 0x07)];
714 
715 	/* Check that the heartbeat value is within it's range ;
716 	 * if not reset to the default */
717 	if (usb_pcwd_set_heartbeat(usb_pcwd, heartbeat)) {
718 		usb_pcwd_set_heartbeat(usb_pcwd, WATCHDOG_HEARTBEAT);
719 		pr_info("heartbeat value must be 0<heartbeat<65536, using %d\n",
720 			WATCHDOG_HEARTBEAT);
721 	}
722 
723 	retval = register_reboot_notifier(&usb_pcwd_notifier);
724 	if (retval != 0) {
725 		pr_err("cannot register reboot notifier (err=%d)\n", retval);
726 		goto error;
727 	}
728 
729 	retval = misc_register(&usb_pcwd_temperature_miscdev);
730 	if (retval != 0) {
731 		pr_err("cannot register miscdev on minor=%d (err=%d)\n",
732 		       TEMP_MINOR, retval);
733 		goto err_out_unregister_reboot;
734 	}
735 
736 	retval = misc_register(&usb_pcwd_miscdev);
737 	if (retval != 0) {
738 		pr_err("cannot register miscdev on minor=%d (err=%d)\n",
739 		       WATCHDOG_MINOR, retval);
740 		goto err_out_misc_deregister;
741 	}
742 
743 	/* we can register the device now, as it is ready */
744 	usb_set_intfdata(interface, usb_pcwd);
745 
746 	pr_info("initialized. heartbeat=%d sec (nowayout=%d)\n",
747 		heartbeat, nowayout);
748 
749 	return 0;
750 
751 err_out_misc_deregister:
752 	misc_deregister(&usb_pcwd_temperature_miscdev);
753 err_out_unregister_reboot:
754 	unregister_reboot_notifier(&usb_pcwd_notifier);
755 error:
756 	if (usb_pcwd)
757 		usb_pcwd_delete(usb_pcwd);
758 	usb_pcwd_device = NULL;
759 	return retval;
760 }
761 
762 
763 /**
764  *	usb_pcwd_disconnect
765  *
766  *	Called by the usb core when the device is removed from the system.
767  *
768  *	This routine guarantees that the driver will not submit any more urbs
769  *	by clearing dev->udev.
770  */
771 static void usb_pcwd_disconnect(struct usb_interface *interface)
772 {
773 	struct usb_pcwd_private *usb_pcwd;
774 
775 	/* prevent races with open() */
776 	mutex_lock(&disconnect_mutex);
777 
778 	usb_pcwd = usb_get_intfdata(interface);
779 	usb_set_intfdata(interface, NULL);
780 
781 	mutex_lock(&usb_pcwd->mtx);
782 
783 	/* Stop the timer before we leave */
784 	if (!nowayout)
785 		usb_pcwd_stop(usb_pcwd);
786 
787 	/* We should now stop communicating with the USB PCWD device */
788 	usb_pcwd->exists = 0;
789 
790 	/* Deregister */
791 	misc_deregister(&usb_pcwd_miscdev);
792 	misc_deregister(&usb_pcwd_temperature_miscdev);
793 	unregister_reboot_notifier(&usb_pcwd_notifier);
794 
795 	mutex_unlock(&usb_pcwd->mtx);
796 
797 	/* Delete the USB PCWD device */
798 	usb_pcwd_delete(usb_pcwd);
799 
800 	cards_found--;
801 
802 	mutex_unlock(&disconnect_mutex);
803 
804 	pr_info("USB PC Watchdog disconnected\n");
805 }
806 
807 module_usb_driver(usb_pcwd_driver);
808