xref: /openbmc/linux/drivers/usb/class/usblp.c (revision 22246614)
1 /*
2  * usblp.c
3  *
4  * Copyright (c) 1999 Michael Gee	<michael@linuxspecific.com>
5  * Copyright (c) 1999 Pavel Machek	<pavel@suse.cz>
6  * Copyright (c) 2000 Randy Dunlap	<rdunlap@xenotime.net>
7  * Copyright (c) 2000 Vojtech Pavlik	<vojtech@suse.cz>
8  # Copyright (c) 2001 Pete Zaitcev	<zaitcev@redhat.com>
9  # Copyright (c) 2001 David Paschal	<paschal@rcsis.com>
10  * Copyright (c) 2006 Oliver Neukum	<oliver@neukum.name>
11  *
12  * USB Printer Device Class driver for USB printers and printer cables
13  *
14  * Sponsored by SuSE
15  *
16  * ChangeLog:
17  *	v0.1 - thorough cleaning, URBification, almost a rewrite
18  *	v0.2 - some more cleanups
19  *	v0.3 - cleaner again, waitqueue fixes
20  *	v0.4 - fixes in unidirectional mode
21  *	v0.5 - add DEVICE_ID string support
22  *	v0.6 - never time out
23  *	v0.7 - fixed bulk-IN read and poll (David Paschal)
24  *	v0.8 - add devfs support
25  *	v0.9 - fix unplug-while-open paths
26  *	v0.10- remove sleep_on, fix error on oom (oliver@neukum.org)
27  *	v0.11 - add proto_bias option (Pete Zaitcev)
28  *	v0.12 - add hpoj.sourceforge.net ioctls (David Paschal)
29  *	v0.13 - alloc space for statusbuf (<status> not on stack);
30  *		use usb_buffer_alloc() for read buf & write buf;
31  *      none  - Maintained in Linux kernel after v0.13
32  */
33 
34 /*
35  * This program is free software; you can redistribute it and/or modify
36  * it under the terms of the GNU General Public License as published by
37  * the Free Software Foundation; either version 2 of the License, or
38  * (at your option) any later version.
39  *
40  * This program is distributed in the hope that it will be useful,
41  * but WITHOUT ANY WARRANTY; without even the implied warranty of
42  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
43  * GNU General Public License for more details.
44  *
45  * You should have received a copy of the GNU General Public License
46  * along with this program; if not, write to the Free Software
47  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
48  */
49 
50 #include <linux/module.h>
51 #include <linux/kernel.h>
52 #include <linux/sched.h>
53 #include <linux/signal.h>
54 #include <linux/poll.h>
55 #include <linux/init.h>
56 #include <linux/slab.h>
57 #include <linux/lp.h>
58 #include <linux/mutex.h>
59 #undef DEBUG
60 #include <linux/usb.h>
61 
62 /*
63  * Version Information
64  */
65 #define DRIVER_AUTHOR "Michael Gee, Pavel Machek, Vojtech Pavlik, Randy Dunlap, Pete Zaitcev, David Paschal"
66 #define DRIVER_DESC "USB Printer Device Class driver"
67 
68 #define USBLP_BUF_SIZE		8192
69 #define USBLP_BUF_SIZE_IN	1024
70 #define USBLP_DEVICE_ID_SIZE	1024
71 
72 /* ioctls: */
73 #define IOCNR_GET_DEVICE_ID		1
74 #define IOCNR_GET_PROTOCOLS		2
75 #define IOCNR_SET_PROTOCOL		3
76 #define IOCNR_HP_SET_CHANNEL		4
77 #define IOCNR_GET_BUS_ADDRESS		5
78 #define IOCNR_GET_VID_PID		6
79 #define IOCNR_SOFT_RESET		7
80 /* Get device_id string: */
81 #define LPIOC_GET_DEVICE_ID(len) _IOC(_IOC_READ, 'P', IOCNR_GET_DEVICE_ID, len)
82 /* The following ioctls were added for http://hpoj.sourceforge.net: */
83 /* Get two-int array:
84  * [0]=current protocol (1=7/1/1, 2=7/1/2, 3=7/1/3),
85  * [1]=supported protocol mask (mask&(1<<n)!=0 means 7/1/n supported): */
86 #define LPIOC_GET_PROTOCOLS(len) _IOC(_IOC_READ, 'P', IOCNR_GET_PROTOCOLS, len)
87 /* Set protocol (arg: 1=7/1/1, 2=7/1/2, 3=7/1/3): */
88 #define LPIOC_SET_PROTOCOL _IOC(_IOC_WRITE, 'P', IOCNR_SET_PROTOCOL, 0)
89 /* Set channel number (HP Vendor-specific command): */
90 #define LPIOC_HP_SET_CHANNEL _IOC(_IOC_WRITE, 'P', IOCNR_HP_SET_CHANNEL, 0)
91 /* Get two-int array: [0]=bus number, [1]=device address: */
92 #define LPIOC_GET_BUS_ADDRESS(len) _IOC(_IOC_READ, 'P', IOCNR_GET_BUS_ADDRESS, len)
93 /* Get two-int array: [0]=vendor ID, [1]=product ID: */
94 #define LPIOC_GET_VID_PID(len) _IOC(_IOC_READ, 'P', IOCNR_GET_VID_PID, len)
95 /* Perform class specific soft reset */
96 #define LPIOC_SOFT_RESET _IOC(_IOC_NONE, 'P', IOCNR_SOFT_RESET, 0);
97 
98 /*
99  * A DEVICE_ID string may include the printer's serial number.
100  * It should end with a semi-colon (';').
101  * An example from an HP 970C DeskJet printer is (this is one long string,
102  * with the serial number changed):
103 MFG:HEWLETT-PACKARD;MDL:DESKJET 970C;CMD:MLC,PCL,PML;CLASS:PRINTER;DESCRIPTION:Hewlett-Packard DeskJet 970C;SERN:US970CSEPROF;VSTATUS:$HB0$NC0,ff,DN,IDLE,CUT,K1,C0,DP,NR,KP000,CP027;VP:0800,FL,B0;VJ:                    ;
104  */
105 
106 /*
107  * USB Printer Requests
108  */
109 
110 #define USBLP_REQ_GET_ID			0x00
111 #define USBLP_REQ_GET_STATUS			0x01
112 #define USBLP_REQ_RESET				0x02
113 #define USBLP_REQ_HP_CHANNEL_CHANGE_REQUEST	0x00	/* HP Vendor-specific */
114 
115 #define USBLP_MINORS		16
116 #define USBLP_MINOR_BASE	0
117 
118 #define USBLP_CTL_TIMEOUT	5000			/* 5 seconds */
119 
120 #define USBLP_FIRST_PROTOCOL	1
121 #define USBLP_LAST_PROTOCOL	3
122 #define USBLP_MAX_PROTOCOLS	(USBLP_LAST_PROTOCOL+1)
123 
124 /*
125  * some arbitrary status buffer size;
126  * need a status buffer that is allocated via kmalloc(), not on stack
127  */
128 #define STATUS_BUF_SIZE		8
129 
130 /*
131  * Locks down the locking order:
132  * ->wmut locks wstatus.
133  * ->mut locks the whole usblp, except [rw]complete, and thus, by indirection,
134  * [rw]status. We only touch status when we know the side idle.
135  * ->lock locks what interrupt accesses.
136  */
137 struct usblp {
138 	struct usb_device 	*dev;			/* USB device */
139 	struct mutex		wmut;
140 	struct mutex		mut;
141 	spinlock_t		lock;		/* locks rcomplete, wcomplete */
142 	char			*readbuf;		/* read transfer_buffer */
143 	char			*statusbuf;		/* status transfer_buffer */
144 	struct usb_anchor	urbs;
145 	wait_queue_head_t	rwait, wwait;
146 	int			readcount;		/* Counter for reads */
147 	int			ifnum;			/* Interface number */
148 	struct usb_interface	*intf;			/* The interface */
149 	/* Alternate-setting numbers and endpoints for each protocol
150 	 * (7/1/{index=1,2,3}) that the device supports: */
151 	struct {
152 		int				alt_setting;
153 		struct usb_endpoint_descriptor	*epwrite;
154 		struct usb_endpoint_descriptor	*epread;
155 	}			protocol[USBLP_MAX_PROTOCOLS];
156 	int			current_protocol;
157 	int			minor;			/* minor number of device */
158 	int			wcomplete, rcomplete;
159 	int			wstatus;	/* bytes written or error */
160 	int			rstatus;	/* bytes ready or error */
161 	unsigned int		quirks;			/* quirks flags */
162 	unsigned int		flags;			/* mode flags */
163 	unsigned char		used;			/* True if open */
164 	unsigned char		present;		/* True if not disconnected */
165 	unsigned char		bidir;			/* interface is bidirectional */
166 	unsigned char		sleeping;		/* interface is suspended */
167 	unsigned char		no_paper;		/* Paper Out happened */
168 	unsigned char		*device_id_string;	/* IEEE 1284 DEVICE ID string (ptr) */
169 							/* first 2 bytes are (big-endian) length */
170 };
171 
172 #ifdef DEBUG
173 static void usblp_dump(struct usblp *usblp) {
174 	int p;
175 
176 	dbg("usblp=0x%p", usblp);
177 	dbg("dev=0x%p", usblp->dev);
178 	dbg("present=%d", usblp->present);
179 	dbg("readbuf=0x%p", usblp->readbuf);
180 	dbg("readcount=%d", usblp->readcount);
181 	dbg("ifnum=%d", usblp->ifnum);
182     for (p = USBLP_FIRST_PROTOCOL; p <= USBLP_LAST_PROTOCOL; p++) {
183 	dbg("protocol[%d].alt_setting=%d", p, usblp->protocol[p].alt_setting);
184 	dbg("protocol[%d].epwrite=%p", p, usblp->protocol[p].epwrite);
185 	dbg("protocol[%d].epread=%p", p, usblp->protocol[p].epread);
186     }
187 	dbg("current_protocol=%d", usblp->current_protocol);
188 	dbg("minor=%d", usblp->minor);
189 	dbg("wstatus=%d", usblp->wstatus);
190 	dbg("rstatus=%d", usblp->rstatus);
191 	dbg("quirks=%d", usblp->quirks);
192 	dbg("used=%d", usblp->used);
193 	dbg("bidir=%d", usblp->bidir);
194 	dbg("sleeping=%d", usblp->sleeping);
195 	dbg("device_id_string=\"%s\"",
196 		usblp->device_id_string ?
197 			usblp->device_id_string + 2 :
198 			(unsigned char *)"(null)");
199 }
200 #endif
201 
202 /* Quirks: various printer quirks are handled by this table & its flags. */
203 
204 struct quirk_printer_struct {
205 	__u16 vendorId;
206 	__u16 productId;
207 	unsigned int quirks;
208 };
209 
210 #define USBLP_QUIRK_BIDIR	0x1	/* reports bidir but requires unidirectional mode (no INs/reads) */
211 #define USBLP_QUIRK_USB_INIT	0x2	/* needs vendor USB init string */
212 #define USBLP_QUIRK_BAD_CLASS	0x4	/* descriptor uses vendor-specific Class or SubClass */
213 
214 static const struct quirk_printer_struct quirk_printers[] = {
215 	{ 0x03f0, 0x0004, USBLP_QUIRK_BIDIR }, /* HP DeskJet 895C */
216 	{ 0x03f0, 0x0104, USBLP_QUIRK_BIDIR }, /* HP DeskJet 880C */
217 	{ 0x03f0, 0x0204, USBLP_QUIRK_BIDIR }, /* HP DeskJet 815C */
218 	{ 0x03f0, 0x0304, USBLP_QUIRK_BIDIR }, /* HP DeskJet 810C/812C */
219 	{ 0x03f0, 0x0404, USBLP_QUIRK_BIDIR }, /* HP DeskJet 830C */
220 	{ 0x03f0, 0x0504, USBLP_QUIRK_BIDIR }, /* HP DeskJet 885C */
221 	{ 0x03f0, 0x0604, USBLP_QUIRK_BIDIR }, /* HP DeskJet 840C */
222 	{ 0x03f0, 0x0804, USBLP_QUIRK_BIDIR }, /* HP DeskJet 816C */
223 	{ 0x03f0, 0x1104, USBLP_QUIRK_BIDIR }, /* HP Deskjet 959C */
224 	{ 0x0409, 0xefbe, USBLP_QUIRK_BIDIR }, /* NEC Picty900 (HP OEM) */
225 	{ 0x0409, 0xbef4, USBLP_QUIRK_BIDIR }, /* NEC Picty760 (HP OEM) */
226 	{ 0x0409, 0xf0be, USBLP_QUIRK_BIDIR }, /* NEC Picty920 (HP OEM) */
227 	{ 0x0409, 0xf1be, USBLP_QUIRK_BIDIR }, /* NEC Picty800 (HP OEM) */
228 	{ 0x0482, 0x0010, USBLP_QUIRK_BIDIR }, /* Kyocera Mita FS 820, by zut <kernel@zut.de> */
229 	{ 0x04b8, 0x0202, USBLP_QUIRK_BAD_CLASS }, /* Seiko Epson Receipt Printer M129C */
230 	{ 0, 0 }
231 };
232 
233 static int usblp_wwait(struct usblp *usblp, int nonblock);
234 static int usblp_wtest(struct usblp *usblp, int nonblock);
235 static int usblp_rwait_and_lock(struct usblp *usblp, int nonblock);
236 static int usblp_rtest(struct usblp *usblp, int nonblock);
237 static int usblp_submit_read(struct usblp *usblp);
238 static int usblp_select_alts(struct usblp *usblp);
239 static int usblp_set_protocol(struct usblp *usblp, int protocol);
240 static int usblp_cache_device_id_string(struct usblp *usblp);
241 
242 /* forward reference to make our lives easier */
243 static struct usb_driver usblp_driver;
244 static DEFINE_MUTEX(usblp_mutex);	/* locks the existence of usblp's */
245 
246 /*
247  * Functions for usblp control messages.
248  */
249 
250 static int usblp_ctrl_msg(struct usblp *usblp, int request, int type, int dir, int recip, int value, void *buf, int len)
251 {
252 	int retval;
253 	int index = usblp->ifnum;
254 
255 	/* High byte has the interface index.
256 	   Low byte has the alternate setting.
257 	 */
258 	if ((request == USBLP_REQ_GET_ID) && (type == USB_TYPE_CLASS)) {
259 	  index = (usblp->ifnum<<8)|usblp->protocol[usblp->current_protocol].alt_setting;
260 	}
261 
262 	retval = usb_control_msg(usblp->dev,
263 		dir ? usb_rcvctrlpipe(usblp->dev, 0) : usb_sndctrlpipe(usblp->dev, 0),
264 		request, type | dir | recip, value, index, buf, len, USBLP_CTL_TIMEOUT);
265 	dbg("usblp_control_msg: rq: 0x%02x dir: %d recip: %d value: %d idx: %d len: %#x result: %d",
266 		request, !!dir, recip, value, index, len, retval);
267 	return retval < 0 ? retval : 0;
268 }
269 
270 #define usblp_read_status(usblp, status)\
271 	usblp_ctrl_msg(usblp, USBLP_REQ_GET_STATUS, USB_TYPE_CLASS, USB_DIR_IN, USB_RECIP_INTERFACE, 0, status, 1)
272 #define usblp_get_id(usblp, config, id, maxlen)\
273 	usblp_ctrl_msg(usblp, USBLP_REQ_GET_ID, USB_TYPE_CLASS, USB_DIR_IN, USB_RECIP_INTERFACE, config, id, maxlen)
274 #define usblp_reset(usblp)\
275 	usblp_ctrl_msg(usblp, USBLP_REQ_RESET, USB_TYPE_CLASS, USB_DIR_OUT, USB_RECIP_OTHER, 0, NULL, 0)
276 
277 #define usblp_hp_channel_change_request(usblp, channel, buffer) \
278 	usblp_ctrl_msg(usblp, USBLP_REQ_HP_CHANNEL_CHANGE_REQUEST, USB_TYPE_VENDOR, USB_DIR_IN, USB_RECIP_INTERFACE, channel, buffer, 1)
279 
280 /*
281  * See the description for usblp_select_alts() below for the usage
282  * explanation.  Look into your /proc/bus/usb/devices and dmesg in
283  * case of any trouble.
284  */
285 static int proto_bias = -1;
286 
287 /*
288  * URB callback.
289  */
290 
291 static void usblp_bulk_read(struct urb *urb)
292 {
293 	struct usblp *usblp = urb->context;
294 	int status = urb->status;
295 
296 	if (usblp->present && usblp->used) {
297 		if (status)
298 			printk(KERN_WARNING "usblp%d: "
299 			    "nonzero read bulk status received: %d\n",
300 			    usblp->minor, status);
301 	}
302 	spin_lock(&usblp->lock);
303 	if (status < 0)
304 		usblp->rstatus = status;
305 	else
306 		usblp->rstatus = urb->actual_length;
307 	usblp->rcomplete = 1;
308 	wake_up(&usblp->rwait);
309 	spin_unlock(&usblp->lock);
310 
311 	usb_free_urb(urb);
312 }
313 
314 static void usblp_bulk_write(struct urb *urb)
315 {
316 	struct usblp *usblp = urb->context;
317 	int status = urb->status;
318 
319 	if (usblp->present && usblp->used) {
320 		if (status)
321 			printk(KERN_WARNING "usblp%d: "
322 			    "nonzero write bulk status received: %d\n",
323 			    usblp->minor, status);
324 	}
325 	spin_lock(&usblp->lock);
326 	if (status < 0)
327 		usblp->wstatus = status;
328 	else
329 		usblp->wstatus = urb->actual_length;
330 	usblp->no_paper = 0;
331 	usblp->wcomplete = 1;
332 	wake_up(&usblp->wwait);
333 	spin_unlock(&usblp->lock);
334 
335 	usb_free_urb(urb);
336 }
337 
338 /*
339  * Get and print printer errors.
340  */
341 
342 static const char *usblp_messages[] = { "ok", "out of paper", "off-line", "on fire" };
343 
344 static int usblp_check_status(struct usblp *usblp, int err)
345 {
346 	unsigned char status, newerr = 0;
347 	int error;
348 
349 	mutex_lock(&usblp->mut);
350 	if ((error = usblp_read_status(usblp, usblp->statusbuf)) < 0) {
351 		mutex_unlock(&usblp->mut);
352 		if (printk_ratelimit())
353 			printk(KERN_ERR
354 				"usblp%d: error %d reading printer status\n",
355 				usblp->minor, error);
356 		return 0;
357 	}
358 	status = *usblp->statusbuf;
359 	mutex_unlock(&usblp->mut);
360 
361 	if (~status & LP_PERRORP)
362 		newerr = 3;
363 	if (status & LP_POUTPA)
364 		newerr = 1;
365 	if (~status & LP_PSELECD)
366 		newerr = 2;
367 
368 	if (newerr != err) {
369 		printk(KERN_INFO "usblp%d: %s\n",
370 		   usblp->minor, usblp_messages[newerr]);
371 	}
372 
373 	return newerr;
374 }
375 
376 static int handle_bidir (struct usblp *usblp)
377 {
378 	if (usblp->bidir && usblp->used && !usblp->sleeping) {
379 		if (usblp_submit_read(usblp) < 0)
380 			return -EIO;
381 	}
382 	return 0;
383 }
384 
385 /*
386  * File op functions.
387  */
388 
389 static int usblp_open(struct inode *inode, struct file *file)
390 {
391 	int minor = iminor(inode);
392 	struct usblp *usblp;
393 	struct usb_interface *intf;
394 	int retval;
395 
396 	if (minor < 0)
397 		return -ENODEV;
398 
399 	mutex_lock (&usblp_mutex);
400 
401 	retval = -ENODEV;
402 	intf = usb_find_interface(&usblp_driver, minor);
403 	if (!intf) {
404 		goto out;
405 	}
406 	usblp = usb_get_intfdata (intf);
407 	if (!usblp || !usblp->dev || !usblp->present)
408 		goto out;
409 
410 	retval = -EBUSY;
411 	if (usblp->used)
412 		goto out;
413 
414 	/*
415 	 * We do not implement LP_ABORTOPEN/LPABORTOPEN for two reasons:
416 	 *  - We do not want persistent state which close(2) does not clear
417 	 *  - It is not used anyway, according to CUPS people
418 	 */
419 
420 	retval = usb_autopm_get_interface(intf);
421 	if (retval < 0)
422 		goto out;
423 	usblp->used = 1;
424 	file->private_data = usblp;
425 
426 	usblp->wcomplete = 1; /* we begin writeable */
427 	usblp->wstatus = 0;
428 	usblp->rcomplete = 0;
429 
430 	if (handle_bidir(usblp) < 0) {
431 		usb_autopm_put_interface(intf);
432 		usblp->used = 0;
433 		file->private_data = NULL;
434 		retval = -EIO;
435 	}
436 out:
437 	mutex_unlock (&usblp_mutex);
438 	return retval;
439 }
440 
441 static void usblp_cleanup (struct usblp *usblp)
442 {
443 	printk(KERN_INFO "usblp%d: removed\n", usblp->minor);
444 
445 	kfree(usblp->readbuf);
446 	kfree (usblp->device_id_string);
447 	kfree (usblp->statusbuf);
448 	kfree (usblp);
449 }
450 
451 static void usblp_unlink_urbs(struct usblp *usblp)
452 {
453 	usb_kill_anchored_urbs(&usblp->urbs);
454 }
455 
456 static int usblp_release(struct inode *inode, struct file *file)
457 {
458 	struct usblp *usblp = file->private_data;
459 
460 	usblp->flags &= ~LP_ABORT;
461 
462 	mutex_lock (&usblp_mutex);
463 	usblp->used = 0;
464 	if (usblp->present) {
465 		usblp_unlink_urbs(usblp);
466 		usb_autopm_put_interface(usblp->intf);
467 	} else 		/* finish cleanup from disconnect */
468 		usblp_cleanup (usblp);
469 	mutex_unlock (&usblp_mutex);
470 	return 0;
471 }
472 
473 /* No kernel lock - fine */
474 static unsigned int usblp_poll(struct file *file, struct poll_table_struct *wait)
475 {
476 	int ret;
477 	unsigned long flags;
478 
479 	struct usblp *usblp = file->private_data;
480 	/* Should we check file->f_mode & FMODE_WRITE before poll_wait()? */
481 	poll_wait(file, &usblp->rwait, wait);
482 	poll_wait(file, &usblp->wwait, wait);
483 	spin_lock_irqsave(&usblp->lock, flags);
484 	ret = ((usblp->bidir && usblp->rcomplete) ? POLLIN  | POLLRDNORM : 0) |
485 	   ((usblp->no_paper || usblp->wcomplete) ? POLLOUT | POLLWRNORM : 0);
486 	spin_unlock_irqrestore(&usblp->lock, flags);
487 	return ret;
488 }
489 
490 static long usblp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
491 {
492 	struct usblp *usblp = file->private_data;
493 	int length, err, i;
494 	unsigned char newChannel;
495 	int status;
496 	int twoints[2];
497 	int retval = 0;
498 
499 	mutex_lock (&usblp->mut);
500 	if (!usblp->present) {
501 		retval = -ENODEV;
502 		goto done;
503 	}
504 
505 	if (usblp->sleeping) {
506 		retval = -ENODEV;
507 		goto done;
508 	}
509 
510 	dbg("usblp_ioctl: cmd=0x%x (%c nr=%d len=%d dir=%d)", cmd, _IOC_TYPE(cmd),
511 		_IOC_NR(cmd), _IOC_SIZE(cmd), _IOC_DIR(cmd) );
512 
513 	if (_IOC_TYPE(cmd) == 'P')	/* new-style ioctl number */
514 
515 		switch (_IOC_NR(cmd)) {
516 
517 			case IOCNR_GET_DEVICE_ID: /* get the DEVICE_ID string */
518 				if (_IOC_DIR(cmd) != _IOC_READ) {
519 					retval = -EINVAL;
520 					goto done;
521 				}
522 
523 				length = usblp_cache_device_id_string(usblp);
524 				if (length < 0) {
525 					retval = length;
526 					goto done;
527 				}
528 				if (length > _IOC_SIZE(cmd))
529 					length = _IOC_SIZE(cmd); /* truncate */
530 
531 				if (copy_to_user((void __user *) arg,
532 						usblp->device_id_string,
533 						(unsigned long) length)) {
534 					retval = -EFAULT;
535 					goto done;
536 				}
537 
538 				break;
539 
540 			case IOCNR_GET_PROTOCOLS:
541 				if (_IOC_DIR(cmd) != _IOC_READ ||
542 				    _IOC_SIZE(cmd) < sizeof(twoints)) {
543 					retval = -EINVAL;
544 					goto done;
545 				}
546 
547 				twoints[0] = usblp->current_protocol;
548 				twoints[1] = 0;
549 				for (i = USBLP_FIRST_PROTOCOL;
550 				     i <= USBLP_LAST_PROTOCOL; i++) {
551 					if (usblp->protocol[i].alt_setting >= 0)
552 						twoints[1] |= (1<<i);
553 				}
554 
555 				if (copy_to_user((void __user *)arg,
556 						(unsigned char *)twoints,
557 						sizeof(twoints))) {
558 					retval = -EFAULT;
559 					goto done;
560 				}
561 
562 				break;
563 
564 			case IOCNR_SET_PROTOCOL:
565 				if (_IOC_DIR(cmd) != _IOC_WRITE) {
566 					retval = -EINVAL;
567 					goto done;
568 				}
569 
570 #ifdef DEBUG
571 				if (arg == -10) {
572 					usblp_dump(usblp);
573 					break;
574 				}
575 #endif
576 
577 				usblp_unlink_urbs(usblp);
578 				retval = usblp_set_protocol(usblp, arg);
579 				if (retval < 0) {
580 					usblp_set_protocol(usblp,
581 						usblp->current_protocol);
582 				}
583 				break;
584 
585 			case IOCNR_HP_SET_CHANNEL:
586 				if (_IOC_DIR(cmd) != _IOC_WRITE ||
587 				    le16_to_cpu(usblp->dev->descriptor.idVendor) != 0x03F0 ||
588 				    usblp->quirks & USBLP_QUIRK_BIDIR) {
589 					retval = -EINVAL;
590 					goto done;
591 				}
592 
593 				err = usblp_hp_channel_change_request(usblp,
594 					arg, &newChannel);
595 				if (err < 0) {
596 					err("usblp%d: error = %d setting "
597 						"HP channel",
598 						usblp->minor, err);
599 					retval = -EIO;
600 					goto done;
601 				}
602 
603 				dbg("usblp%d requested/got HP channel %ld/%d",
604 					usblp->minor, arg, newChannel);
605 				break;
606 
607 			case IOCNR_GET_BUS_ADDRESS:
608 				if (_IOC_DIR(cmd) != _IOC_READ ||
609 				    _IOC_SIZE(cmd) < sizeof(twoints)) {
610 					retval = -EINVAL;
611 					goto done;
612 				}
613 
614 				twoints[0] = usblp->dev->bus->busnum;
615 				twoints[1] = usblp->dev->devnum;
616 				if (copy_to_user((void __user *)arg,
617 						(unsigned char *)twoints,
618 						sizeof(twoints))) {
619 					retval = -EFAULT;
620 					goto done;
621 				}
622 
623 				dbg("usblp%d is bus=%d, device=%d",
624 					usblp->minor, twoints[0], twoints[1]);
625 				break;
626 
627 			case IOCNR_GET_VID_PID:
628 				if (_IOC_DIR(cmd) != _IOC_READ ||
629 				    _IOC_SIZE(cmd) < sizeof(twoints)) {
630 					retval = -EINVAL;
631 					goto done;
632 				}
633 
634 				twoints[0] = le16_to_cpu(usblp->dev->descriptor.idVendor);
635 				twoints[1] = le16_to_cpu(usblp->dev->descriptor.idProduct);
636 				if (copy_to_user((void __user *)arg,
637 						(unsigned char *)twoints,
638 						sizeof(twoints))) {
639 					retval = -EFAULT;
640 					goto done;
641 				}
642 
643 				dbg("usblp%d is VID=0x%4.4X, PID=0x%4.4X",
644 					usblp->minor, twoints[0], twoints[1]);
645 				break;
646 
647 			case IOCNR_SOFT_RESET:
648 				if (_IOC_DIR(cmd) != _IOC_NONE) {
649 					retval = -EINVAL;
650 					goto done;
651 				}
652 				retval = usblp_reset(usblp);
653 				break;
654 			default:
655 				retval = -ENOTTY;
656 		}
657 	else	/* old-style ioctl value */
658 		switch (cmd) {
659 
660 			case LPGETSTATUS:
661 				if ((retval = usblp_read_status(usblp, usblp->statusbuf))) {
662 					if (printk_ratelimit())
663 						printk(KERN_ERR "usblp%d:"
664 						    "failed reading printer status (%d)\n",
665 						    usblp->minor, retval);
666 					retval = -EIO;
667 					goto done;
668 				}
669 				status = *usblp->statusbuf;
670 				if (copy_to_user ((void __user *)arg, &status, sizeof(int)))
671 					retval = -EFAULT;
672 				break;
673 
674 			case LPABORT:
675 				if (arg)
676 					usblp->flags |= LP_ABORT;
677 				else
678 					usblp->flags &= ~LP_ABORT;
679 				break;
680 
681 			default:
682 				retval = -ENOTTY;
683 		}
684 
685 done:
686 	mutex_unlock (&usblp->mut);
687 	return retval;
688 }
689 
690 static struct urb *usblp_new_writeurb(struct usblp *usblp, int transfer_length)
691 {
692 	struct urb *urb;
693 	char *writebuf;
694 
695 	if ((writebuf = kmalloc(transfer_length, GFP_KERNEL)) == NULL)
696 		return NULL;
697 	if ((urb = usb_alloc_urb(0, GFP_KERNEL)) == NULL) {
698 		kfree(writebuf);
699 		return NULL;
700 	}
701 
702 	usb_fill_bulk_urb(urb, usblp->dev,
703 		usb_sndbulkpipe(usblp->dev,
704 		 usblp->protocol[usblp->current_protocol].epwrite->bEndpointAddress),
705 		writebuf, transfer_length, usblp_bulk_write, usblp);
706 	urb->transfer_flags |= URB_FREE_BUFFER;
707 
708 	return urb;
709 }
710 
711 static ssize_t usblp_write(struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
712 {
713 	struct usblp *usblp = file->private_data;
714 	struct urb *writeurb;
715 	int rv;
716 	int transfer_length;
717 	ssize_t writecount = 0;
718 
719 	if (mutex_lock_interruptible(&usblp->wmut)) {
720 		rv = -EINTR;
721 		goto raise_biglock;
722 	}
723 	if ((rv = usblp_wwait(usblp, !!(file->f_flags & O_NONBLOCK))) < 0)
724 		goto raise_wait;
725 
726 	while (writecount < count) {
727 		/*
728 		 * Step 1: Submit next block.
729 		 */
730 		if ((transfer_length = count - writecount) > USBLP_BUF_SIZE)
731 			transfer_length = USBLP_BUF_SIZE;
732 
733 		rv = -ENOMEM;
734 		if ((writeurb = usblp_new_writeurb(usblp, transfer_length)) == NULL)
735 			goto raise_urb;
736 		usb_anchor_urb(writeurb, &usblp->urbs);
737 
738 		if (copy_from_user(writeurb->transfer_buffer,
739 				   buffer + writecount, transfer_length)) {
740 			rv = -EFAULT;
741 			goto raise_badaddr;
742 		}
743 
744 		spin_lock_irq(&usblp->lock);
745 		usblp->wcomplete = 0;
746 		spin_unlock_irq(&usblp->lock);
747 		if ((rv = usb_submit_urb(writeurb, GFP_KERNEL)) < 0) {
748 			usblp->wstatus = 0;
749 			spin_lock_irq(&usblp->lock);
750 			usblp->no_paper = 0;
751 			usblp->wcomplete = 1;
752 			wake_up(&usblp->wwait);
753 			spin_unlock_irq(&usblp->lock);
754 			if (rv != -ENOMEM)
755 				rv = -EIO;
756 			goto raise_submit;
757 		}
758 
759 		/*
760 		 * Step 2: Wait for transfer to end, collect results.
761 		 */
762 		rv = usblp_wwait(usblp, !!(file->f_flags&O_NONBLOCK));
763 		if (rv < 0) {
764 			if (rv == -EAGAIN) {
765 				/* Presume that it's going to complete well. */
766 				writecount += transfer_length;
767 			}
768 			if (rv == -ENOSPC) {
769 				spin_lock_irq(&usblp->lock);
770 				usblp->no_paper = 1;	/* Mark for poll(2) */
771 				spin_unlock_irq(&usblp->lock);
772 				writecount += transfer_length;
773 			}
774 			/* Leave URB dangling, to be cleaned on close. */
775 			goto collect_error;
776 		}
777 
778 		if (usblp->wstatus < 0) {
779 			rv = -EIO;
780 			goto collect_error;
781 		}
782 		/*
783 		 * This is critical: it must be our URB, not other writer's.
784 		 * The wmut exists mainly to cover us here.
785 		 */
786 		writecount += usblp->wstatus;
787 	}
788 
789 	mutex_unlock(&usblp->wmut);
790 	return writecount;
791 
792 raise_submit:
793 raise_badaddr:
794 	usb_unanchor_urb(writeurb);
795 	usb_free_urb(writeurb);
796 raise_urb:
797 raise_wait:
798 collect_error:		/* Out of raise sequence */
799 	mutex_unlock(&usblp->wmut);
800 raise_biglock:
801 	return writecount ? writecount : rv;
802 }
803 
804 /*
805  * Notice that we fail to restart in a few cases: on EFAULT, on restart
806  * error, etc. This is the historical behaviour. In all such cases we return
807  * EIO, and applications loop in order to get the new read going.
808  */
809 static ssize_t usblp_read(struct file *file, char __user *buffer, size_t len, loff_t *ppos)
810 {
811 	struct usblp *usblp = file->private_data;
812 	ssize_t count;
813 	ssize_t avail;
814 	int rv;
815 
816 	if (!usblp->bidir)
817 		return -EINVAL;
818 
819 	rv = usblp_rwait_and_lock(usblp, !!(file->f_flags & O_NONBLOCK));
820 	if (rv < 0)
821 		return rv;
822 
823 	if ((avail = usblp->rstatus) < 0) {
824 		printk(KERN_ERR "usblp%d: error %d reading from printer\n",
825 		    usblp->minor, (int)avail);
826 		usblp_submit_read(usblp);
827 		count = -EIO;
828 		goto done;
829 	}
830 
831 	count = len < avail - usblp->readcount ? len : avail - usblp->readcount;
832 	if (count != 0 &&
833 	    copy_to_user(buffer, usblp->readbuf + usblp->readcount, count)) {
834 		count = -EFAULT;
835 		goto done;
836 	}
837 
838 	if ((usblp->readcount += count) == avail) {
839 		if (usblp_submit_read(usblp) < 0) {
840 			/* We don't want to leak USB return codes into errno. */
841 			if (count == 0)
842 				count = -EIO;
843 			goto done;
844 		}
845 	}
846 
847 done:
848 	mutex_unlock (&usblp->mut);
849 	return count;
850 }
851 
852 /*
853  * Wait for the write path to come idle.
854  * This is called under the ->wmut, so the idle path stays idle.
855  *
856  * Our write path has a peculiar property: it does not buffer like a tty,
857  * but waits for the write to succeed. This allows our ->release to bug out
858  * without waiting for writes to drain. But it obviously does not work
859  * when O_NONBLOCK is set. So, applications setting O_NONBLOCK must use
860  * select(2) or poll(2) to wait for the buffer to drain before closing.
861  * Alternatively, set blocking mode with fcntl and issue a zero-size write.
862  */
863 static int usblp_wwait(struct usblp *usblp, int nonblock)
864 {
865 	DECLARE_WAITQUEUE(waita, current);
866 	int rc;
867 	int err = 0;
868 
869 	add_wait_queue(&usblp->wwait, &waita);
870 	for (;;) {
871 		set_current_state(TASK_INTERRUPTIBLE);
872 		if (mutex_lock_interruptible(&usblp->mut)) {
873 			rc = -EINTR;
874 			break;
875 		}
876 		rc = usblp_wtest(usblp, nonblock);
877 		mutex_unlock(&usblp->mut);
878 		if (rc <= 0)
879 			break;
880 
881 		if (usblp->flags & LP_ABORT) {
882 			if (schedule_timeout(msecs_to_jiffies(5000)) == 0) {
883 				err = usblp_check_status(usblp, err);
884 				if (err == 1) {	/* Paper out */
885 					rc = -ENOSPC;
886 					break;
887 				}
888 			}
889 		} else {
890 			schedule();
891 		}
892 	}
893 	set_current_state(TASK_RUNNING);
894 	remove_wait_queue(&usblp->wwait, &waita);
895 	return rc;
896 }
897 
898 static int usblp_wtest(struct usblp *usblp, int nonblock)
899 {
900 	unsigned long flags;
901 
902 	if (!usblp->present)
903 		return -ENODEV;
904 	if (signal_pending(current))
905 		return -EINTR;
906 	spin_lock_irqsave(&usblp->lock, flags);
907 	if (usblp->wcomplete) {
908 		spin_unlock_irqrestore(&usblp->lock, flags);
909 		return 0;
910 	}
911 	spin_unlock_irqrestore(&usblp->lock, flags);
912 	if (usblp->sleeping)
913 		return -ENODEV;
914 	if (nonblock)
915 		return -EAGAIN;
916 	return 1;
917 }
918 
919 /*
920  * Wait for read bytes to become available. This probably should have been
921  * called usblp_r_lock_and_wait(), because we lock first. But it's a traditional
922  * name for functions which lock and return.
923  *
924  * We do not use wait_event_interruptible because it makes locking iffy.
925  */
926 static int usblp_rwait_and_lock(struct usblp *usblp, int nonblock)
927 {
928 	DECLARE_WAITQUEUE(waita, current);
929 	int rc;
930 
931 	add_wait_queue(&usblp->rwait, &waita);
932 	for (;;) {
933 		if (mutex_lock_interruptible(&usblp->mut)) {
934 			rc = -EINTR;
935 			break;
936 		}
937 		set_current_state(TASK_INTERRUPTIBLE);
938 		if ((rc = usblp_rtest(usblp, nonblock)) < 0) {
939 			mutex_unlock(&usblp->mut);
940 			break;
941 		}
942 		if (rc == 0)	/* Keep it locked */
943 			break;
944 		mutex_unlock(&usblp->mut);
945 		schedule();
946 	}
947 	set_current_state(TASK_RUNNING);
948 	remove_wait_queue(&usblp->rwait, &waita);
949 	return rc;
950 }
951 
952 static int usblp_rtest(struct usblp *usblp, int nonblock)
953 {
954 	unsigned long flags;
955 
956 	if (!usblp->present)
957 		return -ENODEV;
958 	if (signal_pending(current))
959 		return -EINTR;
960 	spin_lock_irqsave(&usblp->lock, flags);
961 	if (usblp->rcomplete) {
962 		spin_unlock_irqrestore(&usblp->lock, flags);
963 		return 0;
964 	}
965 	spin_unlock_irqrestore(&usblp->lock, flags);
966 	if (usblp->sleeping)
967 		return -ENODEV;
968 	if (nonblock)
969 		return -EAGAIN;
970 	return 1;
971 }
972 
973 /*
974  * Please check ->bidir and other such things outside for now.
975  */
976 static int usblp_submit_read(struct usblp *usblp)
977 {
978 	struct urb *urb;
979 	unsigned long flags;
980 	int rc;
981 
982 	rc = -ENOMEM;
983 	if ((urb = usb_alloc_urb(0, GFP_KERNEL)) == NULL)
984 		goto raise_urb;
985 
986 	usb_fill_bulk_urb(urb, usblp->dev,
987 		usb_rcvbulkpipe(usblp->dev,
988 		  usblp->protocol[usblp->current_protocol].epread->bEndpointAddress),
989 		usblp->readbuf, USBLP_BUF_SIZE_IN,
990 		usblp_bulk_read, usblp);
991 	usb_anchor_urb(urb, &usblp->urbs);
992 
993 	spin_lock_irqsave(&usblp->lock, flags);
994 	usblp->readcount = 0; /* XXX Why here? */
995 	usblp->rcomplete = 0;
996 	spin_unlock_irqrestore(&usblp->lock, flags);
997 	if ((rc = usb_submit_urb(urb, GFP_KERNEL)) < 0) {
998 		dbg("error submitting urb (%d)", rc);
999 		spin_lock_irqsave(&usblp->lock, flags);
1000 		usblp->rstatus = rc;
1001 		usblp->rcomplete = 1;
1002 		spin_unlock_irqrestore(&usblp->lock, flags);
1003 		goto raise_submit;
1004 	}
1005 
1006 	return 0;
1007 
1008 raise_submit:
1009 	usb_unanchor_urb(urb);
1010 	usb_free_urb(urb);
1011 raise_urb:
1012 	return rc;
1013 }
1014 
1015 /*
1016  * Checks for printers that have quirks, such as requiring unidirectional
1017  * communication but reporting bidirectional; currently some HP printers
1018  * have this flaw (HP 810, 880, 895, etc.), or needing an init string
1019  * sent at each open (like some Epsons).
1020  * Returns 1 if found, 0 if not found.
1021  *
1022  * HP recommended that we use the bidirectional interface but
1023  * don't attempt any bulk IN transfers from the IN endpoint.
1024  * Here's some more detail on the problem:
1025  * The problem is not that it isn't bidirectional though. The problem
1026  * is that if you request a device ID, or status information, while
1027  * the buffers are full, the return data will end up in the print data
1028  * buffer. For example if you make sure you never request the device ID
1029  * while you are sending print data, and you don't try to query the
1030  * printer status every couple of milliseconds, you will probably be OK.
1031  */
1032 static unsigned int usblp_quirks (__u16 vendor, __u16 product)
1033 {
1034 	int i;
1035 
1036 	for (i = 0; quirk_printers[i].vendorId; i++) {
1037 		if (vendor == quirk_printers[i].vendorId &&
1038 		    product == quirk_printers[i].productId)
1039 			return quirk_printers[i].quirks;
1040  	}
1041 	return 0;
1042 }
1043 
1044 static const struct file_operations usblp_fops = {
1045 	.owner =	THIS_MODULE,
1046 	.read =		usblp_read,
1047 	.write =	usblp_write,
1048 	.poll =		usblp_poll,
1049 	.unlocked_ioctl =	usblp_ioctl,
1050 	.compat_ioctl =		usblp_ioctl,
1051 	.open =		usblp_open,
1052 	.release =	usblp_release,
1053 };
1054 
1055 static struct usb_class_driver usblp_class = {
1056 	.name =		"lp%d",
1057 	.fops =		&usblp_fops,
1058 	.minor_base =	USBLP_MINOR_BASE,
1059 };
1060 
1061 static ssize_t usblp_show_ieee1284_id(struct device *dev, struct device_attribute *attr, char *buf)
1062 {
1063 	struct usb_interface *intf = to_usb_interface(dev);
1064 	struct usblp *usblp = usb_get_intfdata (intf);
1065 
1066 	if (usblp->device_id_string[0] == 0 &&
1067 	    usblp->device_id_string[1] == 0)
1068 		return 0;
1069 
1070 	return sprintf(buf, "%s", usblp->device_id_string+2);
1071 }
1072 
1073 static DEVICE_ATTR(ieee1284_id, S_IRUGO, usblp_show_ieee1284_id, NULL);
1074 
1075 static int usblp_probe(struct usb_interface *intf,
1076 		       const struct usb_device_id *id)
1077 {
1078 	struct usb_device *dev = interface_to_usbdev (intf);
1079 	struct usblp *usblp = NULL;
1080 	int protocol;
1081 	int retval;
1082 
1083 	/* Malloc and start initializing usblp structure so we can use it
1084 	 * directly. */
1085 	if (!(usblp = kzalloc(sizeof(struct usblp), GFP_KERNEL))) {
1086 		retval = -ENOMEM;
1087 		goto abort;
1088 	}
1089 	usblp->dev = dev;
1090 	mutex_init(&usblp->wmut);
1091 	mutex_init (&usblp->mut);
1092 	spin_lock_init(&usblp->lock);
1093 	init_waitqueue_head(&usblp->rwait);
1094 	init_waitqueue_head(&usblp->wwait);
1095 	init_usb_anchor(&usblp->urbs);
1096 	usblp->ifnum = intf->cur_altsetting->desc.bInterfaceNumber;
1097 	usblp->intf = intf;
1098 
1099 	/* Malloc device ID string buffer to the largest expected length,
1100 	 * since we can re-query it on an ioctl and a dynamic string
1101 	 * could change in length. */
1102 	if (!(usblp->device_id_string = kmalloc(USBLP_DEVICE_ID_SIZE, GFP_KERNEL))) {
1103 		retval = -ENOMEM;
1104 		goto abort;
1105 	}
1106 
1107 	/*
1108 	 * Allocate read buffer. We somewhat wastefully
1109 	 * malloc both regardless of bidirectionality, because the
1110 	 * alternate setting can be changed later via an ioctl.
1111 	 */
1112 	if (!(usblp->readbuf = kmalloc(USBLP_BUF_SIZE_IN, GFP_KERNEL))) {
1113 		retval = -ENOMEM;
1114 		goto abort;
1115 	}
1116 
1117 	/* Allocate buffer for printer status */
1118 	usblp->statusbuf = kmalloc(STATUS_BUF_SIZE, GFP_KERNEL);
1119 	if (!usblp->statusbuf) {
1120 		retval = -ENOMEM;
1121 		goto abort;
1122 	}
1123 
1124 	/* Lookup quirks for this printer. */
1125 	usblp->quirks = usblp_quirks(
1126 		le16_to_cpu(dev->descriptor.idVendor),
1127 		le16_to_cpu(dev->descriptor.idProduct));
1128 
1129 	/* Analyze and pick initial alternate settings and endpoints. */
1130 	protocol = usblp_select_alts(usblp);
1131 	if (protocol < 0) {
1132 		dbg("incompatible printer-class device 0x%4.4X/0x%4.4X",
1133 			le16_to_cpu(dev->descriptor.idVendor),
1134 			le16_to_cpu(dev->descriptor.idProduct));
1135 		retval = -ENODEV;
1136 		goto abort;
1137 	}
1138 
1139 	/* Setup the selected alternate setting and endpoints. */
1140 	if (usblp_set_protocol(usblp, protocol) < 0) {
1141 		retval = -ENODEV;	/* ->probe isn't ->ioctl */
1142 		goto abort;
1143 	}
1144 
1145 	/* Retrieve and store the device ID string. */
1146 	usblp_cache_device_id_string(usblp);
1147 	retval = device_create_file(&intf->dev, &dev_attr_ieee1284_id);
1148 	if (retval)
1149 		goto abort_intfdata;
1150 
1151 #ifdef DEBUG
1152 	usblp_check_status(usblp, 0);
1153 #endif
1154 
1155 	usb_set_intfdata (intf, usblp);
1156 
1157 	usblp->present = 1;
1158 
1159 	retval = usb_register_dev(intf, &usblp_class);
1160 	if (retval) {
1161 		printk(KERN_ERR "usblp: Not able to get a minor"
1162 		    " (base %u, slice default): %d\n",
1163 		    USBLP_MINOR_BASE, retval);
1164 		goto abort_intfdata;
1165 	}
1166 	usblp->minor = intf->minor;
1167 	printk(KERN_INFO "usblp%d: USB %sdirectional printer dev %d "
1168 		"if %d alt %d proto %d vid 0x%4.4X pid 0x%4.4X\n",
1169 		usblp->minor, usblp->bidir ? "Bi" : "Uni", dev->devnum,
1170 		usblp->ifnum,
1171 		usblp->protocol[usblp->current_protocol].alt_setting,
1172 		usblp->current_protocol,
1173 		le16_to_cpu(usblp->dev->descriptor.idVendor),
1174 		le16_to_cpu(usblp->dev->descriptor.idProduct));
1175 
1176 	return 0;
1177 
1178 abort_intfdata:
1179 	usb_set_intfdata (intf, NULL);
1180 	device_remove_file(&intf->dev, &dev_attr_ieee1284_id);
1181 abort:
1182 	if (usblp) {
1183 		kfree(usblp->readbuf);
1184 		kfree(usblp->statusbuf);
1185 		kfree(usblp->device_id_string);
1186 		kfree(usblp);
1187 	}
1188 	return retval;
1189 }
1190 
1191 /*
1192  * We are a "new" style driver with usb_device_id table,
1193  * but our requirements are too intricate for simple match to handle.
1194  *
1195  * The "proto_bias" option may be used to specify the preferred protocol
1196  * for all USB printers (1=7/1/1, 2=7/1/2, 3=7/1/3).  If the device
1197  * supports the preferred protocol, then we bind to it.
1198  *
1199  * The best interface for us is 7/1/2, because it is compatible
1200  * with a stream of characters. If we find it, we bind to it.
1201  *
1202  * Note that the people from hpoj.sourceforge.net need to be able to
1203  * bind to 7/1/3 (MLC/1284.4), so we provide them ioctls for this purpose.
1204  *
1205  * Failing 7/1/2, we look for 7/1/3, even though it's probably not
1206  * stream-compatible, because this matches the behaviour of the old code.
1207  *
1208  * If nothing else, we bind to 7/1/1 - the unidirectional interface.
1209  */
1210 static int usblp_select_alts(struct usblp *usblp)
1211 {
1212 	struct usb_interface *if_alt;
1213 	struct usb_host_interface *ifd;
1214 	struct usb_endpoint_descriptor *epd, *epwrite, *epread;
1215 	int p, i, e;
1216 
1217 	if_alt = usblp->intf;
1218 
1219 	for (p = 0; p < USBLP_MAX_PROTOCOLS; p++)
1220 		usblp->protocol[p].alt_setting = -1;
1221 
1222 	/* Find out what we have. */
1223 	for (i = 0; i < if_alt->num_altsetting; i++) {
1224 		ifd = &if_alt->altsetting[i];
1225 
1226 		if (ifd->desc.bInterfaceClass != 7 || ifd->desc.bInterfaceSubClass != 1)
1227 			if (!(usblp->quirks & USBLP_QUIRK_BAD_CLASS))
1228 				continue;
1229 
1230 		if (ifd->desc.bInterfaceProtocol < USBLP_FIRST_PROTOCOL ||
1231 		    ifd->desc.bInterfaceProtocol > USBLP_LAST_PROTOCOL)
1232 			continue;
1233 
1234 		/* Look for bulk OUT and IN endpoints. */
1235 		epwrite = epread = NULL;
1236 		for (e = 0; e < ifd->desc.bNumEndpoints; e++) {
1237 			epd = &ifd->endpoint[e].desc;
1238 
1239 			if (usb_endpoint_is_bulk_out(epd))
1240 				if (!epwrite)
1241 					epwrite = epd;
1242 
1243 			if (usb_endpoint_is_bulk_in(epd))
1244 				if (!epread)
1245 					epread = epd;
1246 		}
1247 
1248 		/* Ignore buggy hardware without the right endpoints. */
1249 		if (!epwrite || (ifd->desc.bInterfaceProtocol > 1 && !epread))
1250 			continue;
1251 
1252 		/* Turn off reads for 7/1/1 (unidirectional) interfaces
1253 		 * and buggy bidirectional printers. */
1254 		if (ifd->desc.bInterfaceProtocol == 1) {
1255 			epread = NULL;
1256 		} else if (usblp->quirks & USBLP_QUIRK_BIDIR) {
1257 			printk(KERN_INFO "usblp%d: Disabling reads from "
1258 			    "problematic bidirectional printer\n",
1259 			    usblp->minor);
1260 			epread = NULL;
1261 		}
1262 
1263 		usblp->protocol[ifd->desc.bInterfaceProtocol].alt_setting =
1264 				ifd->desc.bAlternateSetting;
1265 		usblp->protocol[ifd->desc.bInterfaceProtocol].epwrite = epwrite;
1266 		usblp->protocol[ifd->desc.bInterfaceProtocol].epread = epread;
1267 	}
1268 
1269 	/* If our requested protocol is supported, then use it. */
1270 	if (proto_bias >= USBLP_FIRST_PROTOCOL &&
1271 	    proto_bias <= USBLP_LAST_PROTOCOL &&
1272 	    usblp->protocol[proto_bias].alt_setting != -1)
1273 		return proto_bias;
1274 
1275 	/* Ordering is important here. */
1276 	if (usblp->protocol[2].alt_setting != -1)
1277 		return 2;
1278 	if (usblp->protocol[1].alt_setting != -1)
1279 		return 1;
1280 	if (usblp->protocol[3].alt_setting != -1)
1281 		return 3;
1282 
1283 	/* If nothing is available, then don't bind to this device. */
1284 	return -1;
1285 }
1286 
1287 static int usblp_set_protocol(struct usblp *usblp, int protocol)
1288 {
1289 	int r, alts;
1290 
1291 	if (protocol < USBLP_FIRST_PROTOCOL || protocol > USBLP_LAST_PROTOCOL)
1292 		return -EINVAL;
1293 
1294 	alts = usblp->protocol[protocol].alt_setting;
1295 	if (alts < 0)
1296 		return -EINVAL;
1297 	r = usb_set_interface(usblp->dev, usblp->ifnum, alts);
1298 	if (r < 0) {
1299 		printk(KERN_ERR "usblp: can't set desired altsetting %d on interface %d\n",
1300 			alts, usblp->ifnum);
1301 		return r;
1302 	}
1303 
1304 	usblp->bidir = (usblp->protocol[protocol].epread != NULL);
1305 	usblp->current_protocol = protocol;
1306 	dbg("usblp%d set protocol %d", usblp->minor, protocol);
1307 	return 0;
1308 }
1309 
1310 /* Retrieves and caches device ID string.
1311  * Returns length, including length bytes but not null terminator.
1312  * On error, returns a negative errno value. */
1313 static int usblp_cache_device_id_string(struct usblp *usblp)
1314 {
1315 	int err, length;
1316 
1317 	err = usblp_get_id(usblp, 0, usblp->device_id_string, USBLP_DEVICE_ID_SIZE - 1);
1318 	if (err < 0) {
1319 		dbg("usblp%d: error = %d reading IEEE-1284 Device ID string",
1320 			usblp->minor, err);
1321 		usblp->device_id_string[0] = usblp->device_id_string[1] = '\0';
1322 		return -EIO;
1323 	}
1324 
1325 	/* First two bytes are length in big-endian.
1326 	 * They count themselves, and we copy them into
1327 	 * the user's buffer. */
1328 	length = be16_to_cpu(*((__be16 *)usblp->device_id_string));
1329 	if (length < 2)
1330 		length = 2;
1331 	else if (length >= USBLP_DEVICE_ID_SIZE)
1332 		length = USBLP_DEVICE_ID_SIZE - 1;
1333 	usblp->device_id_string[length] = '\0';
1334 
1335 	dbg("usblp%d Device ID string [len=%d]=\"%s\"",
1336 		usblp->minor, length, &usblp->device_id_string[2]);
1337 
1338 	return length;
1339 }
1340 
1341 static void usblp_disconnect(struct usb_interface *intf)
1342 {
1343 	struct usblp *usblp = usb_get_intfdata (intf);
1344 
1345 	usb_deregister_dev(intf, &usblp_class);
1346 
1347 	if (!usblp || !usblp->dev) {
1348 		err("bogus disconnect");
1349 		BUG ();
1350 	}
1351 
1352 	device_remove_file(&intf->dev, &dev_attr_ieee1284_id);
1353 
1354 	mutex_lock (&usblp_mutex);
1355 	mutex_lock (&usblp->mut);
1356 	usblp->present = 0;
1357 	wake_up(&usblp->wwait);
1358 	wake_up(&usblp->rwait);
1359 	usb_set_intfdata (intf, NULL);
1360 
1361 	usblp_unlink_urbs(usblp);
1362 	mutex_unlock (&usblp->mut);
1363 
1364 	if (!usblp->used)
1365 		usblp_cleanup (usblp);
1366 	mutex_unlock (&usblp_mutex);
1367 }
1368 
1369 static int usblp_suspend (struct usb_interface *intf, pm_message_t message)
1370 {
1371 	struct usblp *usblp = usb_get_intfdata (intf);
1372 
1373 	/* we take no more IO */
1374 	usblp->sleeping = 1;
1375 	usblp_unlink_urbs(usblp);
1376 #if 0 /* XXX Do we want this? What if someone is reading, should we fail? */
1377 	/* not strictly necessary, but just in case */
1378 	wake_up(&usblp->wwait);
1379 	wake_up(&usblp->rwait);
1380 #endif
1381 
1382 	return 0;
1383 }
1384 
1385 static int usblp_resume (struct usb_interface *intf)
1386 {
1387 	struct usblp *usblp = usb_get_intfdata (intf);
1388 	int r;
1389 
1390 	usblp->sleeping = 0;
1391 	r = handle_bidir (usblp);
1392 
1393 	return r;
1394 }
1395 
1396 static struct usb_device_id usblp_ids [] = {
1397 	{ USB_DEVICE_INFO(7, 1, 1) },
1398 	{ USB_DEVICE_INFO(7, 1, 2) },
1399 	{ USB_DEVICE_INFO(7, 1, 3) },
1400 	{ USB_INTERFACE_INFO(7, 1, 1) },
1401 	{ USB_INTERFACE_INFO(7, 1, 2) },
1402 	{ USB_INTERFACE_INFO(7, 1, 3) },
1403 	{ USB_DEVICE(0x04b8, 0x0202) },	/* Seiko Epson Receipt Printer M129C */
1404 	{ }						/* Terminating entry */
1405 };
1406 
1407 MODULE_DEVICE_TABLE (usb, usblp_ids);
1408 
1409 static struct usb_driver usblp_driver = {
1410 	.name =		"usblp",
1411 	.probe =	usblp_probe,
1412 	.disconnect =	usblp_disconnect,
1413 	.suspend =	usblp_suspend,
1414 	.resume =	usblp_resume,
1415 	.id_table =	usblp_ids,
1416 	.supports_autosuspend =	1,
1417 };
1418 
1419 static int __init usblp_init(void)
1420 {
1421 	return usb_register(&usblp_driver);
1422 }
1423 
1424 static void __exit usblp_exit(void)
1425 {
1426 	usb_deregister(&usblp_driver);
1427 }
1428 
1429 module_init(usblp_init);
1430 module_exit(usblp_exit);
1431 
1432 MODULE_AUTHOR( DRIVER_AUTHOR );
1433 MODULE_DESCRIPTION( DRIVER_DESC );
1434 module_param(proto_bias, int, S_IRUGO | S_IWUSR);
1435 MODULE_PARM_DESC(proto_bias, "Favourite protocol number");
1436 MODULE_LICENSE("GPL");
1437