xref: /openbmc/linux/drivers/usb/class/usblp.c (revision 643d1f7f)
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 		usblp->used = 0;
432 		file->private_data = NULL;
433 		retval = -EIO;
434 	}
435 out:
436 	mutex_unlock (&usblp_mutex);
437 	return retval;
438 }
439 
440 static void usblp_cleanup (struct usblp *usblp)
441 {
442 	printk(KERN_INFO "usblp%d: removed\n", usblp->minor);
443 
444 	kfree(usblp->readbuf);
445 	kfree (usblp->device_id_string);
446 	kfree (usblp->statusbuf);
447 	kfree (usblp);
448 }
449 
450 static void usblp_unlink_urbs(struct usblp *usblp)
451 {
452 	usb_kill_anchored_urbs(&usblp->urbs);
453 }
454 
455 static int usblp_release(struct inode *inode, struct file *file)
456 {
457 	struct usblp *usblp = file->private_data;
458 
459 	usblp->flags &= ~LP_ABORT;
460 
461 	mutex_lock (&usblp_mutex);
462 	usblp->used = 0;
463 	if (usblp->present) {
464 		usblp_unlink_urbs(usblp);
465 		usb_autopm_put_interface(usblp->intf);
466 	} else 		/* finish cleanup from disconnect */
467 		usblp_cleanup (usblp);
468 	mutex_unlock (&usblp_mutex);
469 	return 0;
470 }
471 
472 /* No kernel lock - fine */
473 static unsigned int usblp_poll(struct file *file, struct poll_table_struct *wait)
474 {
475 	int ret;
476 	unsigned long flags;
477 
478 	struct usblp *usblp = file->private_data;
479 	/* Should we check file->f_mode & FMODE_WRITE before poll_wait()? */
480 	poll_wait(file, &usblp->rwait, wait);
481 	poll_wait(file, &usblp->wwait, wait);
482 	spin_lock_irqsave(&usblp->lock, flags);
483 	ret = ((usblp->bidir && usblp->rcomplete) ? POLLIN  | POLLRDNORM : 0) |
484 	   ((usblp->no_paper || usblp->wcomplete) ? POLLOUT | POLLWRNORM : 0);
485 	spin_unlock_irqrestore(&usblp->lock, flags);
486 	return ret;
487 }
488 
489 static long usblp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
490 {
491 	struct usblp *usblp = file->private_data;
492 	int length, err, i;
493 	unsigned char newChannel;
494 	int status;
495 	int twoints[2];
496 	int retval = 0;
497 
498 	mutex_lock (&usblp->mut);
499 	if (!usblp->present) {
500 		retval = -ENODEV;
501 		goto done;
502 	}
503 
504 	if (usblp->sleeping) {
505 		retval = -ENODEV;
506 		goto done;
507 	}
508 
509 	dbg("usblp_ioctl: cmd=0x%x (%c nr=%d len=%d dir=%d)", cmd, _IOC_TYPE(cmd),
510 		_IOC_NR(cmd), _IOC_SIZE(cmd), _IOC_DIR(cmd) );
511 
512 	if (_IOC_TYPE(cmd) == 'P')	/* new-style ioctl number */
513 
514 		switch (_IOC_NR(cmd)) {
515 
516 			case IOCNR_GET_DEVICE_ID: /* get the DEVICE_ID string */
517 				if (_IOC_DIR(cmd) != _IOC_READ) {
518 					retval = -EINVAL;
519 					goto done;
520 				}
521 
522 				length = usblp_cache_device_id_string(usblp);
523 				if (length < 0) {
524 					retval = length;
525 					goto done;
526 				}
527 				if (length > _IOC_SIZE(cmd))
528 					length = _IOC_SIZE(cmd); /* truncate */
529 
530 				if (copy_to_user((void __user *) arg,
531 						usblp->device_id_string,
532 						(unsigned long) length)) {
533 					retval = -EFAULT;
534 					goto done;
535 				}
536 
537 				break;
538 
539 			case IOCNR_GET_PROTOCOLS:
540 				if (_IOC_DIR(cmd) != _IOC_READ ||
541 				    _IOC_SIZE(cmd) < sizeof(twoints)) {
542 					retval = -EINVAL;
543 					goto done;
544 				}
545 
546 				twoints[0] = usblp->current_protocol;
547 				twoints[1] = 0;
548 				for (i = USBLP_FIRST_PROTOCOL;
549 				     i <= USBLP_LAST_PROTOCOL; i++) {
550 					if (usblp->protocol[i].alt_setting >= 0)
551 						twoints[1] |= (1<<i);
552 				}
553 
554 				if (copy_to_user((void __user *)arg,
555 						(unsigned char *)twoints,
556 						sizeof(twoints))) {
557 					retval = -EFAULT;
558 					goto done;
559 				}
560 
561 				break;
562 
563 			case IOCNR_SET_PROTOCOL:
564 				if (_IOC_DIR(cmd) != _IOC_WRITE) {
565 					retval = -EINVAL;
566 					goto done;
567 				}
568 
569 #ifdef DEBUG
570 				if (arg == -10) {
571 					usblp_dump(usblp);
572 					break;
573 				}
574 #endif
575 
576 				usblp_unlink_urbs(usblp);
577 				retval = usblp_set_protocol(usblp, arg);
578 				if (retval < 0) {
579 					usblp_set_protocol(usblp,
580 						usblp->current_protocol);
581 				}
582 				break;
583 
584 			case IOCNR_HP_SET_CHANNEL:
585 				if (_IOC_DIR(cmd) != _IOC_WRITE ||
586 				    le16_to_cpu(usblp->dev->descriptor.idVendor) != 0x03F0 ||
587 				    usblp->quirks & USBLP_QUIRK_BIDIR) {
588 					retval = -EINVAL;
589 					goto done;
590 				}
591 
592 				err = usblp_hp_channel_change_request(usblp,
593 					arg, &newChannel);
594 				if (err < 0) {
595 					err("usblp%d: error = %d setting "
596 						"HP channel",
597 						usblp->minor, err);
598 					retval = -EIO;
599 					goto done;
600 				}
601 
602 				dbg("usblp%d requested/got HP channel %ld/%d",
603 					usblp->minor, arg, newChannel);
604 				break;
605 
606 			case IOCNR_GET_BUS_ADDRESS:
607 				if (_IOC_DIR(cmd) != _IOC_READ ||
608 				    _IOC_SIZE(cmd) < sizeof(twoints)) {
609 					retval = -EINVAL;
610 					goto done;
611 				}
612 
613 				twoints[0] = usblp->dev->bus->busnum;
614 				twoints[1] = usblp->dev->devnum;
615 				if (copy_to_user((void __user *)arg,
616 						(unsigned char *)twoints,
617 						sizeof(twoints))) {
618 					retval = -EFAULT;
619 					goto done;
620 				}
621 
622 				dbg("usblp%d is bus=%d, device=%d",
623 					usblp->minor, twoints[0], twoints[1]);
624 				break;
625 
626 			case IOCNR_GET_VID_PID:
627 				if (_IOC_DIR(cmd) != _IOC_READ ||
628 				    _IOC_SIZE(cmd) < sizeof(twoints)) {
629 					retval = -EINVAL;
630 					goto done;
631 				}
632 
633 				twoints[0] = le16_to_cpu(usblp->dev->descriptor.idVendor);
634 				twoints[1] = le16_to_cpu(usblp->dev->descriptor.idProduct);
635 				if (copy_to_user((void __user *)arg,
636 						(unsigned char *)twoints,
637 						sizeof(twoints))) {
638 					retval = -EFAULT;
639 					goto done;
640 				}
641 
642 				dbg("usblp%d is VID=0x%4.4X, PID=0x%4.4X",
643 					usblp->minor, twoints[0], twoints[1]);
644 				break;
645 
646 			case IOCNR_SOFT_RESET:
647 				if (_IOC_DIR(cmd) != _IOC_NONE) {
648 					retval = -EINVAL;
649 					goto done;
650 				}
651 				retval = usblp_reset(usblp);
652 				break;
653 			default:
654 				retval = -ENOTTY;
655 		}
656 	else	/* old-style ioctl value */
657 		switch (cmd) {
658 
659 			case LPGETSTATUS:
660 				if ((retval = usblp_read_status(usblp, usblp->statusbuf))) {
661 					if (printk_ratelimit())
662 						printk(KERN_ERR "usblp%d:"
663 						    "failed reading printer status (%d)\n",
664 						    usblp->minor, retval);
665 					retval = -EIO;
666 					goto done;
667 				}
668 				status = *usblp->statusbuf;
669 				if (copy_to_user ((void __user *)arg, &status, sizeof(int)))
670 					retval = -EFAULT;
671 				break;
672 
673 			case LPABORT:
674 				if (arg)
675 					usblp->flags |= LP_ABORT;
676 				else
677 					usblp->flags &= ~LP_ABORT;
678 				break;
679 
680 			default:
681 				retval = -ENOTTY;
682 		}
683 
684 done:
685 	mutex_unlock (&usblp->mut);
686 	return retval;
687 }
688 
689 static struct urb *usblp_new_writeurb(struct usblp *usblp, int transfer_length)
690 {
691 	struct urb *urb;
692 	char *writebuf;
693 
694 	if ((writebuf = kmalloc(transfer_length, GFP_KERNEL)) == NULL)
695 		return NULL;
696 	if ((urb = usb_alloc_urb(0, GFP_KERNEL)) == NULL) {
697 		kfree(writebuf);
698 		return NULL;
699 	}
700 
701 	usb_fill_bulk_urb(urb, usblp->dev,
702 		usb_sndbulkpipe(usblp->dev,
703 		 usblp->protocol[usblp->current_protocol].epwrite->bEndpointAddress),
704 		writebuf, transfer_length, usblp_bulk_write, usblp);
705 	urb->transfer_flags |= URB_FREE_BUFFER;
706 
707 	return urb;
708 }
709 
710 static ssize_t usblp_write(struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
711 {
712 	struct usblp *usblp = file->private_data;
713 	struct urb *writeurb;
714 	int rv;
715 	int transfer_length;
716 	ssize_t writecount = 0;
717 
718 	if (mutex_lock_interruptible(&usblp->wmut)) {
719 		rv = -EINTR;
720 		goto raise_biglock;
721 	}
722 	if ((rv = usblp_wwait(usblp, !!(file->f_flags & O_NONBLOCK))) < 0)
723 		goto raise_wait;
724 
725 	while (writecount < count) {
726 		/*
727 		 * Step 1: Submit next block.
728 		 */
729 		if ((transfer_length = count - writecount) > USBLP_BUF_SIZE)
730 			transfer_length = USBLP_BUF_SIZE;
731 
732 		rv = -ENOMEM;
733 		if ((writeurb = usblp_new_writeurb(usblp, transfer_length)) == NULL)
734 			goto raise_urb;
735 		usb_anchor_urb(writeurb, &usblp->urbs);
736 
737 		if (copy_from_user(writeurb->transfer_buffer,
738 				   buffer + writecount, transfer_length)) {
739 			rv = -EFAULT;
740 			goto raise_badaddr;
741 		}
742 
743 		spin_lock_irq(&usblp->lock);
744 		usblp->wcomplete = 0;
745 		spin_unlock_irq(&usblp->lock);
746 		if ((rv = usb_submit_urb(writeurb, GFP_KERNEL)) < 0) {
747 			usblp->wstatus = 0;
748 			spin_lock_irq(&usblp->lock);
749 			usblp->no_paper = 0;
750 			usblp->wcomplete = 1;
751 			wake_up(&usblp->wwait);
752 			spin_unlock_irq(&usblp->lock);
753 			if (rv != -ENOMEM)
754 				rv = -EIO;
755 			goto raise_submit;
756 		}
757 
758 		/*
759 		 * Step 2: Wait for transfer to end, collect results.
760 		 */
761 		rv = usblp_wwait(usblp, !!(file->f_flags&O_NONBLOCK));
762 		if (rv < 0) {
763 			if (rv == -EAGAIN) {
764 				/* Presume that it's going to complete well. */
765 				writecount += transfer_length;
766 			}
767 			if (rv == -ENOSPC) {
768 				spin_lock_irq(&usblp->lock);
769 				usblp->no_paper = 1;	/* Mark for poll(2) */
770 				spin_unlock_irq(&usblp->lock);
771 				writecount += transfer_length;
772 			}
773 			/* Leave URB dangling, to be cleaned on close. */
774 			goto collect_error;
775 		}
776 
777 		if (usblp->wstatus < 0) {
778 			rv = -EIO;
779 			goto collect_error;
780 		}
781 		/*
782 		 * This is critical: it must be our URB, not other writer's.
783 		 * The wmut exists mainly to cover us here.
784 		 */
785 		writecount += usblp->wstatus;
786 	}
787 
788 	mutex_unlock(&usblp->wmut);
789 	return writecount;
790 
791 raise_submit:
792 raise_badaddr:
793 	usb_unanchor_urb(writeurb);
794 	usb_free_urb(writeurb);
795 raise_urb:
796 raise_wait:
797 collect_error:		/* Out of raise sequence */
798 	mutex_unlock(&usblp->wmut);
799 raise_biglock:
800 	return writecount ? writecount : rv;
801 }
802 
803 /*
804  * Notice that we fail to restart in a few cases: on EFAULT, on restart
805  * error, etc. This is the historical behaviour. In all such cases we return
806  * EIO, and applications loop in order to get the new read going.
807  */
808 static ssize_t usblp_read(struct file *file, char __user *buffer, size_t len, loff_t *ppos)
809 {
810 	struct usblp *usblp = file->private_data;
811 	ssize_t count;
812 	ssize_t avail;
813 	int rv;
814 
815 	if (!usblp->bidir)
816 		return -EINVAL;
817 
818 	rv = usblp_rwait_and_lock(usblp, !!(file->f_flags & O_NONBLOCK));
819 	if (rv < 0)
820 		return rv;
821 
822 	if ((avail = usblp->rstatus) < 0) {
823 		printk(KERN_ERR "usblp%d: error %d reading from printer\n",
824 		    usblp->minor, (int)avail);
825 		usblp_submit_read(usblp);
826 		count = -EIO;
827 		goto done;
828 	}
829 
830 	count = len < avail - usblp->readcount ? len : avail - usblp->readcount;
831 	if (count != 0 &&
832 	    copy_to_user(buffer, usblp->readbuf + usblp->readcount, count)) {
833 		count = -EFAULT;
834 		goto done;
835 	}
836 
837 	if ((usblp->readcount += count) == avail) {
838 		if (usblp_submit_read(usblp) < 0) {
839 			/* We don't want to leak USB return codes into errno. */
840 			if (count == 0)
841 				count = -EIO;
842 			goto done;
843 		}
844 	}
845 
846 done:
847 	mutex_unlock (&usblp->mut);
848 	return count;
849 }
850 
851 /*
852  * Wait for the write path to come idle.
853  * This is called under the ->wmut, so the idle path stays idle.
854  *
855  * Our write path has a peculiar property: it does not buffer like a tty,
856  * but waits for the write to succeed. This allows our ->release to bug out
857  * without waiting for writes to drain. But it obviously does not work
858  * when O_NONBLOCK is set. So, applications setting O_NONBLOCK must use
859  * select(2) or poll(2) to wait for the buffer to drain before closing.
860  * Alternatively, set blocking mode with fcntl and issue a zero-size write.
861  */
862 static int usblp_wwait(struct usblp *usblp, int nonblock)
863 {
864 	DECLARE_WAITQUEUE(waita, current);
865 	int rc;
866 	int err = 0;
867 
868 	add_wait_queue(&usblp->wwait, &waita);
869 	for (;;) {
870 		set_current_state(TASK_INTERRUPTIBLE);
871 		if (mutex_lock_interruptible(&usblp->mut)) {
872 			rc = -EINTR;
873 			break;
874 		}
875 		rc = usblp_wtest(usblp, nonblock);
876 		mutex_unlock(&usblp->mut);
877 		if (rc <= 0)
878 			break;
879 
880 		if (usblp->flags & LP_ABORT) {
881 			if (schedule_timeout(msecs_to_jiffies(5000)) == 0) {
882 				err = usblp_check_status(usblp, err);
883 				if (err == 1) {	/* Paper out */
884 					rc = -ENOSPC;
885 					break;
886 				}
887 			}
888 		} else {
889 			schedule();
890 		}
891 	}
892 	set_current_state(TASK_RUNNING);
893 	remove_wait_queue(&usblp->wwait, &waita);
894 	return rc;
895 }
896 
897 static int usblp_wtest(struct usblp *usblp, int nonblock)
898 {
899 	unsigned long flags;
900 
901 	if (!usblp->present)
902 		return -ENODEV;
903 	if (signal_pending(current))
904 		return -EINTR;
905 	spin_lock_irqsave(&usblp->lock, flags);
906 	if (usblp->wcomplete) {
907 		spin_unlock_irqrestore(&usblp->lock, flags);
908 		return 0;
909 	}
910 	spin_unlock_irqrestore(&usblp->lock, flags);
911 	if (usblp->sleeping)
912 		return -ENODEV;
913 	if (nonblock)
914 		return -EAGAIN;
915 	return 1;
916 }
917 
918 /*
919  * Wait for read bytes to become available. This probably should have been
920  * called usblp_r_lock_and_wait(), because we lock first. But it's a traditional
921  * name for functions which lock and return.
922  *
923  * We do not use wait_event_interruptible because it makes locking iffy.
924  */
925 static int usblp_rwait_and_lock(struct usblp *usblp, int nonblock)
926 {
927 	DECLARE_WAITQUEUE(waita, current);
928 	int rc;
929 
930 	add_wait_queue(&usblp->rwait, &waita);
931 	for (;;) {
932 		if (mutex_lock_interruptible(&usblp->mut)) {
933 			rc = -EINTR;
934 			break;
935 		}
936 		set_current_state(TASK_INTERRUPTIBLE);
937 		if ((rc = usblp_rtest(usblp, nonblock)) < 0) {
938 			mutex_unlock(&usblp->mut);
939 			break;
940 		}
941 		if (rc == 0)	/* Keep it locked */
942 			break;
943 		mutex_unlock(&usblp->mut);
944 		schedule();
945 	}
946 	set_current_state(TASK_RUNNING);
947 	remove_wait_queue(&usblp->rwait, &waita);
948 	return rc;
949 }
950 
951 static int usblp_rtest(struct usblp *usblp, int nonblock)
952 {
953 	unsigned long flags;
954 
955 	if (!usblp->present)
956 		return -ENODEV;
957 	if (signal_pending(current))
958 		return -EINTR;
959 	spin_lock_irqsave(&usblp->lock, flags);
960 	if (usblp->rcomplete) {
961 		spin_unlock_irqrestore(&usblp->lock, flags);
962 		return 0;
963 	}
964 	spin_unlock_irqrestore(&usblp->lock, flags);
965 	if (usblp->sleeping)
966 		return -ENODEV;
967 	if (nonblock)
968 		return -EAGAIN;
969 	return 1;
970 }
971 
972 /*
973  * Please check ->bidir and other such things outside for now.
974  */
975 static int usblp_submit_read(struct usblp *usblp)
976 {
977 	struct urb *urb;
978 	unsigned long flags;
979 	int rc;
980 
981 	rc = -ENOMEM;
982 	if ((urb = usb_alloc_urb(0, GFP_KERNEL)) == NULL)
983 		goto raise_urb;
984 
985 	usb_fill_bulk_urb(urb, usblp->dev,
986 		usb_rcvbulkpipe(usblp->dev,
987 		  usblp->protocol[usblp->current_protocol].epread->bEndpointAddress),
988 		usblp->readbuf, USBLP_BUF_SIZE_IN,
989 		usblp_bulk_read, usblp);
990 	usb_anchor_urb(urb, &usblp->urbs);
991 
992 	spin_lock_irqsave(&usblp->lock, flags);
993 	usblp->readcount = 0; /* XXX Why here? */
994 	usblp->rcomplete = 0;
995 	spin_unlock_irqrestore(&usblp->lock, flags);
996 	if ((rc = usb_submit_urb(urb, GFP_KERNEL)) < 0) {
997 		dbg("error submitting urb (%d)", rc);
998 		spin_lock_irqsave(&usblp->lock, flags);
999 		usblp->rstatus = rc;
1000 		usblp->rcomplete = 1;
1001 		spin_unlock_irqrestore(&usblp->lock, flags);
1002 		goto raise_submit;
1003 	}
1004 
1005 	return 0;
1006 
1007 raise_submit:
1008 	usb_unanchor_urb(urb);
1009 	usb_free_urb(urb);
1010 raise_urb:
1011 	return rc;
1012 }
1013 
1014 /*
1015  * Checks for printers that have quirks, such as requiring unidirectional
1016  * communication but reporting bidirectional; currently some HP printers
1017  * have this flaw (HP 810, 880, 895, etc.), or needing an init string
1018  * sent at each open (like some Epsons).
1019  * Returns 1 if found, 0 if not found.
1020  *
1021  * HP recommended that we use the bidirectional interface but
1022  * don't attempt any bulk IN transfers from the IN endpoint.
1023  * Here's some more detail on the problem:
1024  * The problem is not that it isn't bidirectional though. The problem
1025  * is that if you request a device ID, or status information, while
1026  * the buffers are full, the return data will end up in the print data
1027  * buffer. For example if you make sure you never request the device ID
1028  * while you are sending print data, and you don't try to query the
1029  * printer status every couple of milliseconds, you will probably be OK.
1030  */
1031 static unsigned int usblp_quirks (__u16 vendor, __u16 product)
1032 {
1033 	int i;
1034 
1035 	for (i = 0; quirk_printers[i].vendorId; i++) {
1036 		if (vendor == quirk_printers[i].vendorId &&
1037 		    product == quirk_printers[i].productId)
1038 			return quirk_printers[i].quirks;
1039  	}
1040 	return 0;
1041 }
1042 
1043 static const struct file_operations usblp_fops = {
1044 	.owner =	THIS_MODULE,
1045 	.read =		usblp_read,
1046 	.write =	usblp_write,
1047 	.poll =		usblp_poll,
1048 	.unlocked_ioctl =	usblp_ioctl,
1049 	.compat_ioctl =		usblp_ioctl,
1050 	.open =		usblp_open,
1051 	.release =	usblp_release,
1052 };
1053 
1054 static struct usb_class_driver usblp_class = {
1055 	.name =		"lp%d",
1056 	.fops =		&usblp_fops,
1057 	.minor_base =	USBLP_MINOR_BASE,
1058 };
1059 
1060 static ssize_t usblp_show_ieee1284_id(struct device *dev, struct device_attribute *attr, char *buf)
1061 {
1062 	struct usb_interface *intf = to_usb_interface(dev);
1063 	struct usblp *usblp = usb_get_intfdata (intf);
1064 
1065 	if (usblp->device_id_string[0] == 0 &&
1066 	    usblp->device_id_string[1] == 0)
1067 		return 0;
1068 
1069 	return sprintf(buf, "%s", usblp->device_id_string+2);
1070 }
1071 
1072 static DEVICE_ATTR(ieee1284_id, S_IRUGO, usblp_show_ieee1284_id, NULL);
1073 
1074 static int usblp_probe(struct usb_interface *intf,
1075 		       const struct usb_device_id *id)
1076 {
1077 	struct usb_device *dev = interface_to_usbdev (intf);
1078 	struct usblp *usblp = NULL;
1079 	int protocol;
1080 	int retval;
1081 
1082 	/* Malloc and start initializing usblp structure so we can use it
1083 	 * directly. */
1084 	if (!(usblp = kzalloc(sizeof(struct usblp), GFP_KERNEL))) {
1085 		retval = -ENOMEM;
1086 		goto abort;
1087 	}
1088 	usblp->dev = dev;
1089 	mutex_init(&usblp->wmut);
1090 	mutex_init (&usblp->mut);
1091 	spin_lock_init(&usblp->lock);
1092 	init_waitqueue_head(&usblp->rwait);
1093 	init_waitqueue_head(&usblp->wwait);
1094 	init_usb_anchor(&usblp->urbs);
1095 	usblp->ifnum = intf->cur_altsetting->desc.bInterfaceNumber;
1096 	usblp->intf = intf;
1097 
1098 	/* Malloc device ID string buffer to the largest expected length,
1099 	 * since we can re-query it on an ioctl and a dynamic string
1100 	 * could change in length. */
1101 	if (!(usblp->device_id_string = kmalloc(USBLP_DEVICE_ID_SIZE, GFP_KERNEL))) {
1102 		retval = -ENOMEM;
1103 		goto abort;
1104 	}
1105 
1106 	/*
1107 	 * Allocate read buffer. We somewhat wastefully
1108 	 * malloc both regardless of bidirectionality, because the
1109 	 * alternate setting can be changed later via an ioctl.
1110 	 */
1111 	if (!(usblp->readbuf = kmalloc(USBLP_BUF_SIZE_IN, GFP_KERNEL))) {
1112 		retval = -ENOMEM;
1113 		goto abort;
1114 	}
1115 
1116 	/* Allocate buffer for printer status */
1117 	usblp->statusbuf = kmalloc(STATUS_BUF_SIZE, GFP_KERNEL);
1118 	if (!usblp->statusbuf) {
1119 		retval = -ENOMEM;
1120 		goto abort;
1121 	}
1122 
1123 	/* Lookup quirks for this printer. */
1124 	usblp->quirks = usblp_quirks(
1125 		le16_to_cpu(dev->descriptor.idVendor),
1126 		le16_to_cpu(dev->descriptor.idProduct));
1127 
1128 	/* Analyze and pick initial alternate settings and endpoints. */
1129 	protocol = usblp_select_alts(usblp);
1130 	if (protocol < 0) {
1131 		dbg("incompatible printer-class device 0x%4.4X/0x%4.4X",
1132 			le16_to_cpu(dev->descriptor.idVendor),
1133 			le16_to_cpu(dev->descriptor.idProduct));
1134 		retval = -ENODEV;
1135 		goto abort;
1136 	}
1137 
1138 	/* Setup the selected alternate setting and endpoints. */
1139 	if (usblp_set_protocol(usblp, protocol) < 0) {
1140 		retval = -ENODEV;	/* ->probe isn't ->ioctl */
1141 		goto abort;
1142 	}
1143 
1144 	/* Retrieve and store the device ID string. */
1145 	usblp_cache_device_id_string(usblp);
1146 	retval = device_create_file(&intf->dev, &dev_attr_ieee1284_id);
1147 	if (retval)
1148 		goto abort_intfdata;
1149 
1150 #ifdef DEBUG
1151 	usblp_check_status(usblp, 0);
1152 #endif
1153 
1154 	usb_set_intfdata (intf, usblp);
1155 
1156 	usblp->present = 1;
1157 
1158 	retval = usb_register_dev(intf, &usblp_class);
1159 	if (retval) {
1160 		printk(KERN_ERR "usblp: Not able to get a minor"
1161 		    " (base %u, slice default): %d\n",
1162 		    USBLP_MINOR_BASE, retval);
1163 		goto abort_intfdata;
1164 	}
1165 	usblp->minor = intf->minor;
1166 	printk(KERN_INFO "usblp%d: USB %sdirectional printer dev %d "
1167 		"if %d alt %d proto %d vid 0x%4.4X pid 0x%4.4X\n",
1168 		usblp->minor, usblp->bidir ? "Bi" : "Uni", dev->devnum,
1169 		usblp->ifnum,
1170 		usblp->protocol[usblp->current_protocol].alt_setting,
1171 		usblp->current_protocol,
1172 		le16_to_cpu(usblp->dev->descriptor.idVendor),
1173 		le16_to_cpu(usblp->dev->descriptor.idProduct));
1174 
1175 	return 0;
1176 
1177 abort_intfdata:
1178 	usb_set_intfdata (intf, NULL);
1179 	device_remove_file(&intf->dev, &dev_attr_ieee1284_id);
1180 abort:
1181 	if (usblp) {
1182 		kfree(usblp->readbuf);
1183 		kfree(usblp->statusbuf);
1184 		kfree(usblp->device_id_string);
1185 		kfree(usblp);
1186 	}
1187 	return retval;
1188 }
1189 
1190 /*
1191  * We are a "new" style driver with usb_device_id table,
1192  * but our requirements are too intricate for simple match to handle.
1193  *
1194  * The "proto_bias" option may be used to specify the preferred protocol
1195  * for all USB printers (1=7/1/1, 2=7/1/2, 3=7/1/3).  If the device
1196  * supports the preferred protocol, then we bind to it.
1197  *
1198  * The best interface for us is 7/1/2, because it is compatible
1199  * with a stream of characters. If we find it, we bind to it.
1200  *
1201  * Note that the people from hpoj.sourceforge.net need to be able to
1202  * bind to 7/1/3 (MLC/1284.4), so we provide them ioctls for this purpose.
1203  *
1204  * Failing 7/1/2, we look for 7/1/3, even though it's probably not
1205  * stream-compatible, because this matches the behaviour of the old code.
1206  *
1207  * If nothing else, we bind to 7/1/1 - the unidirectional interface.
1208  */
1209 static int usblp_select_alts(struct usblp *usblp)
1210 {
1211 	struct usb_interface *if_alt;
1212 	struct usb_host_interface *ifd;
1213 	struct usb_endpoint_descriptor *epd, *epwrite, *epread;
1214 	int p, i, e;
1215 
1216 	if_alt = usblp->intf;
1217 
1218 	for (p = 0; p < USBLP_MAX_PROTOCOLS; p++)
1219 		usblp->protocol[p].alt_setting = -1;
1220 
1221 	/* Find out what we have. */
1222 	for (i = 0; i < if_alt->num_altsetting; i++) {
1223 		ifd = &if_alt->altsetting[i];
1224 
1225 		if (ifd->desc.bInterfaceClass != 7 || ifd->desc.bInterfaceSubClass != 1)
1226 			if (!(usblp->quirks & USBLP_QUIRK_BAD_CLASS))
1227 				continue;
1228 
1229 		if (ifd->desc.bInterfaceProtocol < USBLP_FIRST_PROTOCOL ||
1230 		    ifd->desc.bInterfaceProtocol > USBLP_LAST_PROTOCOL)
1231 			continue;
1232 
1233 		/* Look for bulk OUT and IN endpoints. */
1234 		epwrite = epread = NULL;
1235 		for (e = 0; e < ifd->desc.bNumEndpoints; e++) {
1236 			epd = &ifd->endpoint[e].desc;
1237 
1238 			if (usb_endpoint_is_bulk_out(epd))
1239 				if (!epwrite)
1240 					epwrite = epd;
1241 
1242 			if (usb_endpoint_is_bulk_in(epd))
1243 				if (!epread)
1244 					epread = epd;
1245 		}
1246 
1247 		/* Ignore buggy hardware without the right endpoints. */
1248 		if (!epwrite || (ifd->desc.bInterfaceProtocol > 1 && !epread))
1249 			continue;
1250 
1251 		/* Turn off reads for 7/1/1 (unidirectional) interfaces
1252 		 * and buggy bidirectional printers. */
1253 		if (ifd->desc.bInterfaceProtocol == 1) {
1254 			epread = NULL;
1255 		} else if (usblp->quirks & USBLP_QUIRK_BIDIR) {
1256 			printk(KERN_INFO "usblp%d: Disabling reads from "
1257 			    "problematic bidirectional printer\n",
1258 			    usblp->minor);
1259 			epread = NULL;
1260 		}
1261 
1262 		usblp->protocol[ifd->desc.bInterfaceProtocol].alt_setting =
1263 				ifd->desc.bAlternateSetting;
1264 		usblp->protocol[ifd->desc.bInterfaceProtocol].epwrite = epwrite;
1265 		usblp->protocol[ifd->desc.bInterfaceProtocol].epread = epread;
1266 	}
1267 
1268 	/* If our requested protocol is supported, then use it. */
1269 	if (proto_bias >= USBLP_FIRST_PROTOCOL &&
1270 	    proto_bias <= USBLP_LAST_PROTOCOL &&
1271 	    usblp->protocol[proto_bias].alt_setting != -1)
1272 		return proto_bias;
1273 
1274 	/* Ordering is important here. */
1275 	if (usblp->protocol[2].alt_setting != -1)
1276 		return 2;
1277 	if (usblp->protocol[1].alt_setting != -1)
1278 		return 1;
1279 	if (usblp->protocol[3].alt_setting != -1)
1280 		return 3;
1281 
1282 	/* If nothing is available, then don't bind to this device. */
1283 	return -1;
1284 }
1285 
1286 static int usblp_set_protocol(struct usblp *usblp, int protocol)
1287 {
1288 	int r, alts;
1289 
1290 	if (protocol < USBLP_FIRST_PROTOCOL || protocol > USBLP_LAST_PROTOCOL)
1291 		return -EINVAL;
1292 
1293 	alts = usblp->protocol[protocol].alt_setting;
1294 	if (alts < 0)
1295 		return -EINVAL;
1296 	r = usb_set_interface(usblp->dev, usblp->ifnum, alts);
1297 	if (r < 0) {
1298 		printk(KERN_ERR "usblp: can't set desired altsetting %d on interface %d\n",
1299 			alts, usblp->ifnum);
1300 		return r;
1301 	}
1302 
1303 	usblp->bidir = (usblp->protocol[protocol].epread != NULL);
1304 	usblp->current_protocol = protocol;
1305 	dbg("usblp%d set protocol %d", usblp->minor, protocol);
1306 	return 0;
1307 }
1308 
1309 /* Retrieves and caches device ID string.
1310  * Returns length, including length bytes but not null terminator.
1311  * On error, returns a negative errno value. */
1312 static int usblp_cache_device_id_string(struct usblp *usblp)
1313 {
1314 	int err, length;
1315 
1316 	err = usblp_get_id(usblp, 0, usblp->device_id_string, USBLP_DEVICE_ID_SIZE - 1);
1317 	if (err < 0) {
1318 		dbg("usblp%d: error = %d reading IEEE-1284 Device ID string",
1319 			usblp->minor, err);
1320 		usblp->device_id_string[0] = usblp->device_id_string[1] = '\0';
1321 		return -EIO;
1322 	}
1323 
1324 	/* First two bytes are length in big-endian.
1325 	 * They count themselves, and we copy them into
1326 	 * the user's buffer. */
1327 	length = be16_to_cpu(*((__be16 *)usblp->device_id_string));
1328 	if (length < 2)
1329 		length = 2;
1330 	else if (length >= USBLP_DEVICE_ID_SIZE)
1331 		length = USBLP_DEVICE_ID_SIZE - 1;
1332 	usblp->device_id_string[length] = '\0';
1333 
1334 	dbg("usblp%d Device ID string [len=%d]=\"%s\"",
1335 		usblp->minor, length, &usblp->device_id_string[2]);
1336 
1337 	return length;
1338 }
1339 
1340 static void usblp_disconnect(struct usb_interface *intf)
1341 {
1342 	struct usblp *usblp = usb_get_intfdata (intf);
1343 
1344 	usb_deregister_dev(intf, &usblp_class);
1345 
1346 	if (!usblp || !usblp->dev) {
1347 		err("bogus disconnect");
1348 		BUG ();
1349 	}
1350 
1351 	device_remove_file(&intf->dev, &dev_attr_ieee1284_id);
1352 
1353 	mutex_lock (&usblp_mutex);
1354 	mutex_lock (&usblp->mut);
1355 	usblp->present = 0;
1356 	wake_up(&usblp->wwait);
1357 	wake_up(&usblp->rwait);
1358 	usb_set_intfdata (intf, NULL);
1359 
1360 	usblp_unlink_urbs(usblp);
1361 	mutex_unlock (&usblp->mut);
1362 
1363 	if (!usblp->used)
1364 		usblp_cleanup (usblp);
1365 	mutex_unlock (&usblp_mutex);
1366 }
1367 
1368 static int usblp_suspend (struct usb_interface *intf, pm_message_t message)
1369 {
1370 	struct usblp *usblp = usb_get_intfdata (intf);
1371 
1372 	/* we take no more IO */
1373 	usblp->sleeping = 1;
1374 	usblp_unlink_urbs(usblp);
1375 #if 0 /* XXX Do we want this? What if someone is reading, should we fail? */
1376 	/* not strictly necessary, but just in case */
1377 	wake_up(&usblp->wwait);
1378 	wake_up(&usblp->rwait);
1379 #endif
1380 
1381 	return 0;
1382 }
1383 
1384 static int usblp_resume (struct usb_interface *intf)
1385 {
1386 	struct usblp *usblp = usb_get_intfdata (intf);
1387 	int r;
1388 
1389 	usblp->sleeping = 0;
1390 	r = handle_bidir (usblp);
1391 
1392 	return r;
1393 }
1394 
1395 static struct usb_device_id usblp_ids [] = {
1396 	{ USB_DEVICE_INFO(7, 1, 1) },
1397 	{ USB_DEVICE_INFO(7, 1, 2) },
1398 	{ USB_DEVICE_INFO(7, 1, 3) },
1399 	{ USB_INTERFACE_INFO(7, 1, 1) },
1400 	{ USB_INTERFACE_INFO(7, 1, 2) },
1401 	{ USB_INTERFACE_INFO(7, 1, 3) },
1402 	{ USB_DEVICE(0x04b8, 0x0202) },	/* Seiko Epson Receipt Printer M129C */
1403 	{ }						/* Terminating entry */
1404 };
1405 
1406 MODULE_DEVICE_TABLE (usb, usblp_ids);
1407 
1408 static struct usb_driver usblp_driver = {
1409 	.name =		"usblp",
1410 	.probe =	usblp_probe,
1411 	.disconnect =	usblp_disconnect,
1412 	.suspend =	usblp_suspend,
1413 	.resume =	usblp_resume,
1414 	.id_table =	usblp_ids,
1415 	.supports_autosuspend =	1,
1416 };
1417 
1418 static int __init usblp_init(void)
1419 {
1420 	return usb_register(&usblp_driver);
1421 }
1422 
1423 static void __exit usblp_exit(void)
1424 {
1425 	usb_deregister(&usblp_driver);
1426 }
1427 
1428 module_init(usblp_init);
1429 module_exit(usblp_exit);
1430 
1431 MODULE_AUTHOR( DRIVER_AUTHOR );
1432 MODULE_DESCRIPTION( DRIVER_DESC );
1433 module_param(proto_bias, int, S_IRUGO | S_IWUSR);
1434 MODULE_PARM_DESC(proto_bias, "Favourite protocol number");
1435 MODULE_LICENSE("GPL");
1436