xref: /openbmc/linux/drivers/usb/class/usblp.c (revision a09d2831)
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 	{ 0x04f9, 0x000d, USBLP_QUIRK_BIDIR }, /* Brother Industries, Ltd HL-1440 Laser Printer */
230 	{ 0x04b8, 0x0202, USBLP_QUIRK_BAD_CLASS }, /* Seiko Epson Receipt Printer M129C */
231 	{ 0, 0 }
232 };
233 
234 static int usblp_wwait(struct usblp *usblp, int nonblock);
235 static int usblp_wtest(struct usblp *usblp, int nonblock);
236 static int usblp_rwait_and_lock(struct usblp *usblp, int nonblock);
237 static int usblp_rtest(struct usblp *usblp, int nonblock);
238 static int usblp_submit_read(struct usblp *usblp);
239 static int usblp_select_alts(struct usblp *usblp);
240 static int usblp_set_protocol(struct usblp *usblp, int protocol);
241 static int usblp_cache_device_id_string(struct usblp *usblp);
242 
243 /* forward reference to make our lives easier */
244 static struct usb_driver usblp_driver;
245 static DEFINE_MUTEX(usblp_mutex);	/* locks the existence of usblp's */
246 
247 /*
248  * Functions for usblp control messages.
249  */
250 
251 static int usblp_ctrl_msg(struct usblp *usblp, int request, int type, int dir, int recip, int value, void *buf, int len)
252 {
253 	int retval;
254 	int index = usblp->ifnum;
255 
256 	/* High byte has the interface index.
257 	   Low byte has the alternate setting.
258 	 */
259 	if ((request == USBLP_REQ_GET_ID) && (type == USB_TYPE_CLASS)) {
260 	  index = (usblp->ifnum<<8)|usblp->protocol[usblp->current_protocol].alt_setting;
261 	}
262 
263 	retval = usb_control_msg(usblp->dev,
264 		dir ? usb_rcvctrlpipe(usblp->dev, 0) : usb_sndctrlpipe(usblp->dev, 0),
265 		request, type | dir | recip, value, index, buf, len, USBLP_CTL_TIMEOUT);
266 	dbg("usblp_control_msg: rq: 0x%02x dir: %d recip: %d value: %d idx: %d len: %#x result: %d",
267 		request, !!dir, recip, value, index, len, retval);
268 	return retval < 0 ? retval : 0;
269 }
270 
271 #define usblp_read_status(usblp, status)\
272 	usblp_ctrl_msg(usblp, USBLP_REQ_GET_STATUS, USB_TYPE_CLASS, USB_DIR_IN, USB_RECIP_INTERFACE, 0, status, 1)
273 #define usblp_get_id(usblp, config, id, maxlen)\
274 	usblp_ctrl_msg(usblp, USBLP_REQ_GET_ID, USB_TYPE_CLASS, USB_DIR_IN, USB_RECIP_INTERFACE, config, id, maxlen)
275 #define usblp_reset(usblp)\
276 	usblp_ctrl_msg(usblp, USBLP_REQ_RESET, USB_TYPE_CLASS, USB_DIR_OUT, USB_RECIP_OTHER, 0, NULL, 0)
277 
278 #define usblp_hp_channel_change_request(usblp, channel, buffer) \
279 	usblp_ctrl_msg(usblp, USBLP_REQ_HP_CHANNEL_CHANGE_REQUEST, USB_TYPE_VENDOR, USB_DIR_IN, USB_RECIP_INTERFACE, channel, buffer, 1)
280 
281 /*
282  * See the description for usblp_select_alts() below for the usage
283  * explanation.  Look into your /proc/bus/usb/devices and dmesg in
284  * case of any trouble.
285  */
286 static int proto_bias = -1;
287 
288 /*
289  * URB callback.
290  */
291 
292 static void usblp_bulk_read(struct urb *urb)
293 {
294 	struct usblp *usblp = urb->context;
295 	int status = urb->status;
296 
297 	if (usblp->present && usblp->used) {
298 		if (status)
299 			printk(KERN_WARNING "usblp%d: "
300 			    "nonzero read bulk status received: %d\n",
301 			    usblp->minor, status);
302 	}
303 	spin_lock(&usblp->lock);
304 	if (status < 0)
305 		usblp->rstatus = status;
306 	else
307 		usblp->rstatus = urb->actual_length;
308 	usblp->rcomplete = 1;
309 	wake_up(&usblp->rwait);
310 	spin_unlock(&usblp->lock);
311 
312 	usb_free_urb(urb);
313 }
314 
315 static void usblp_bulk_write(struct urb *urb)
316 {
317 	struct usblp *usblp = urb->context;
318 	int status = urb->status;
319 
320 	if (usblp->present && usblp->used) {
321 		if (status)
322 			printk(KERN_WARNING "usblp%d: "
323 			    "nonzero write bulk status received: %d\n",
324 			    usblp->minor, status);
325 	}
326 	spin_lock(&usblp->lock);
327 	if (status < 0)
328 		usblp->wstatus = status;
329 	else
330 		usblp->wstatus = urb->actual_length;
331 	usblp->no_paper = 0;
332 	usblp->wcomplete = 1;
333 	wake_up(&usblp->wwait);
334 	spin_unlock(&usblp->lock);
335 
336 	usb_free_urb(urb);
337 }
338 
339 /*
340  * Get and print printer errors.
341  */
342 
343 static const char *usblp_messages[] = { "ok", "out of paper", "off-line", "on fire" };
344 
345 static int usblp_check_status(struct usblp *usblp, int err)
346 {
347 	unsigned char status, newerr = 0;
348 	int error;
349 
350 	mutex_lock(&usblp->mut);
351 	if ((error = usblp_read_status(usblp, usblp->statusbuf)) < 0) {
352 		mutex_unlock(&usblp->mut);
353 		if (printk_ratelimit())
354 			printk(KERN_ERR
355 				"usblp%d: error %d reading printer status\n",
356 				usblp->minor, error);
357 		return 0;
358 	}
359 	status = *usblp->statusbuf;
360 	mutex_unlock(&usblp->mut);
361 
362 	if (~status & LP_PERRORP)
363 		newerr = 3;
364 	if (status & LP_POUTPA)
365 		newerr = 1;
366 	if (~status & LP_PSELECD)
367 		newerr = 2;
368 
369 	if (newerr != err) {
370 		printk(KERN_INFO "usblp%d: %s\n",
371 		   usblp->minor, usblp_messages[newerr]);
372 	}
373 
374 	return newerr;
375 }
376 
377 static int handle_bidir (struct usblp *usblp)
378 {
379 	if (usblp->bidir && usblp->used && !usblp->sleeping) {
380 		if (usblp_submit_read(usblp) < 0)
381 			return -EIO;
382 	}
383 	return 0;
384 }
385 
386 /*
387  * File op functions.
388  */
389 
390 static int usblp_open(struct inode *inode, struct file *file)
391 {
392 	int minor = iminor(inode);
393 	struct usblp *usblp;
394 	struct usb_interface *intf;
395 	int retval;
396 
397 	if (minor < 0)
398 		return -ENODEV;
399 
400 	mutex_lock (&usblp_mutex);
401 
402 	retval = -ENODEV;
403 	intf = usb_find_interface(&usblp_driver, minor);
404 	if (!intf) {
405 		goto out;
406 	}
407 	usblp = usb_get_intfdata (intf);
408 	if (!usblp || !usblp->dev || !usblp->present)
409 		goto out;
410 
411 	retval = -EBUSY;
412 	if (usblp->used)
413 		goto out;
414 
415 	/*
416 	 * We do not implement LP_ABORTOPEN/LPABORTOPEN for two reasons:
417 	 *  - We do not want persistent state which close(2) does not clear
418 	 *  - It is not used anyway, according to CUPS people
419 	 */
420 
421 	retval = usb_autopm_get_interface(intf);
422 	if (retval < 0)
423 		goto out;
424 	usblp->used = 1;
425 	file->private_data = usblp;
426 
427 	usblp->wcomplete = 1; /* we begin writeable */
428 	usblp->wstatus = 0;
429 	usblp->rcomplete = 0;
430 
431 	if (handle_bidir(usblp) < 0) {
432 		usb_autopm_put_interface(intf);
433 		usblp->used = 0;
434 		file->private_data = NULL;
435 		retval = -EIO;
436 	}
437 out:
438 	mutex_unlock (&usblp_mutex);
439 	return retval;
440 }
441 
442 static void usblp_cleanup (struct usblp *usblp)
443 {
444 	printk(KERN_INFO "usblp%d: removed\n", usblp->minor);
445 
446 	kfree(usblp->readbuf);
447 	kfree (usblp->device_id_string);
448 	kfree (usblp->statusbuf);
449 	kfree (usblp);
450 }
451 
452 static void usblp_unlink_urbs(struct usblp *usblp)
453 {
454 	usb_kill_anchored_urbs(&usblp->urbs);
455 }
456 
457 static int usblp_release(struct inode *inode, struct file *file)
458 {
459 	struct usblp *usblp = file->private_data;
460 
461 	usblp->flags &= ~LP_ABORT;
462 
463 	mutex_lock (&usblp_mutex);
464 	usblp->used = 0;
465 	if (usblp->present) {
466 		usblp_unlink_urbs(usblp);
467 		usb_autopm_put_interface(usblp->intf);
468 	} else 		/* finish cleanup from disconnect */
469 		usblp_cleanup (usblp);
470 	mutex_unlock (&usblp_mutex);
471 	return 0;
472 }
473 
474 /* No kernel lock - fine */
475 static unsigned int usblp_poll(struct file *file, struct poll_table_struct *wait)
476 {
477 	int ret;
478 	unsigned long flags;
479 
480 	struct usblp *usblp = file->private_data;
481 	/* Should we check file->f_mode & FMODE_WRITE before poll_wait()? */
482 	poll_wait(file, &usblp->rwait, wait);
483 	poll_wait(file, &usblp->wwait, wait);
484 	spin_lock_irqsave(&usblp->lock, flags);
485 	ret = ((usblp->bidir && usblp->rcomplete) ? POLLIN  | POLLRDNORM : 0) |
486 	   ((usblp->no_paper || usblp->wcomplete) ? POLLOUT | POLLWRNORM : 0);
487 	spin_unlock_irqrestore(&usblp->lock, flags);
488 	return ret;
489 }
490 
491 static long usblp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
492 {
493 	struct usblp *usblp = file->private_data;
494 	int length, err, i;
495 	unsigned char newChannel;
496 	int status;
497 	int twoints[2];
498 	int retval = 0;
499 
500 	mutex_lock (&usblp->mut);
501 	if (!usblp->present) {
502 		retval = -ENODEV;
503 		goto done;
504 	}
505 
506 	if (usblp->sleeping) {
507 		retval = -ENODEV;
508 		goto done;
509 	}
510 
511 	dbg("usblp_ioctl: cmd=0x%x (%c nr=%d len=%d dir=%d)", cmd, _IOC_TYPE(cmd),
512 		_IOC_NR(cmd), _IOC_SIZE(cmd), _IOC_DIR(cmd) );
513 
514 	if (_IOC_TYPE(cmd) == 'P')	/* new-style ioctl number */
515 
516 		switch (_IOC_NR(cmd)) {
517 
518 			case IOCNR_GET_DEVICE_ID: /* get the DEVICE_ID string */
519 				if (_IOC_DIR(cmd) != _IOC_READ) {
520 					retval = -EINVAL;
521 					goto done;
522 				}
523 
524 				length = usblp_cache_device_id_string(usblp);
525 				if (length < 0) {
526 					retval = length;
527 					goto done;
528 				}
529 				if (length > _IOC_SIZE(cmd))
530 					length = _IOC_SIZE(cmd); /* truncate */
531 
532 				if (copy_to_user((void __user *) arg,
533 						usblp->device_id_string,
534 						(unsigned long) length)) {
535 					retval = -EFAULT;
536 					goto done;
537 				}
538 
539 				break;
540 
541 			case IOCNR_GET_PROTOCOLS:
542 				if (_IOC_DIR(cmd) != _IOC_READ ||
543 				    _IOC_SIZE(cmd) < sizeof(twoints)) {
544 					retval = -EINVAL;
545 					goto done;
546 				}
547 
548 				twoints[0] = usblp->current_protocol;
549 				twoints[1] = 0;
550 				for (i = USBLP_FIRST_PROTOCOL;
551 				     i <= USBLP_LAST_PROTOCOL; i++) {
552 					if (usblp->protocol[i].alt_setting >= 0)
553 						twoints[1] |= (1<<i);
554 				}
555 
556 				if (copy_to_user((void __user *)arg,
557 						(unsigned char *)twoints,
558 						sizeof(twoints))) {
559 					retval = -EFAULT;
560 					goto done;
561 				}
562 
563 				break;
564 
565 			case IOCNR_SET_PROTOCOL:
566 				if (_IOC_DIR(cmd) != _IOC_WRITE) {
567 					retval = -EINVAL;
568 					goto done;
569 				}
570 
571 #ifdef DEBUG
572 				if (arg == -10) {
573 					usblp_dump(usblp);
574 					break;
575 				}
576 #endif
577 
578 				usblp_unlink_urbs(usblp);
579 				retval = usblp_set_protocol(usblp, arg);
580 				if (retval < 0) {
581 					usblp_set_protocol(usblp,
582 						usblp->current_protocol);
583 				}
584 				break;
585 
586 			case IOCNR_HP_SET_CHANNEL:
587 				if (_IOC_DIR(cmd) != _IOC_WRITE ||
588 				    le16_to_cpu(usblp->dev->descriptor.idVendor) != 0x03F0 ||
589 				    usblp->quirks & USBLP_QUIRK_BIDIR) {
590 					retval = -EINVAL;
591 					goto done;
592 				}
593 
594 				err = usblp_hp_channel_change_request(usblp,
595 					arg, &newChannel);
596 				if (err < 0) {
597 					dev_err(&usblp->dev->dev,
598 						"usblp%d: error = %d setting "
599 						"HP channel\n",
600 						usblp->minor, err);
601 					retval = -EIO;
602 					goto done;
603 				}
604 
605 				dbg("usblp%d requested/got HP channel %ld/%d",
606 					usblp->minor, arg, newChannel);
607 				break;
608 
609 			case IOCNR_GET_BUS_ADDRESS:
610 				if (_IOC_DIR(cmd) != _IOC_READ ||
611 				    _IOC_SIZE(cmd) < sizeof(twoints)) {
612 					retval = -EINVAL;
613 					goto done;
614 				}
615 
616 				twoints[0] = usblp->dev->bus->busnum;
617 				twoints[1] = usblp->dev->devnum;
618 				if (copy_to_user((void __user *)arg,
619 						(unsigned char *)twoints,
620 						sizeof(twoints))) {
621 					retval = -EFAULT;
622 					goto done;
623 				}
624 
625 				dbg("usblp%d is bus=%d, device=%d",
626 					usblp->minor, twoints[0], twoints[1]);
627 				break;
628 
629 			case IOCNR_GET_VID_PID:
630 				if (_IOC_DIR(cmd) != _IOC_READ ||
631 				    _IOC_SIZE(cmd) < sizeof(twoints)) {
632 					retval = -EINVAL;
633 					goto done;
634 				}
635 
636 				twoints[0] = le16_to_cpu(usblp->dev->descriptor.idVendor);
637 				twoints[1] = le16_to_cpu(usblp->dev->descriptor.idProduct);
638 				if (copy_to_user((void __user *)arg,
639 						(unsigned char *)twoints,
640 						sizeof(twoints))) {
641 					retval = -EFAULT;
642 					goto done;
643 				}
644 
645 				dbg("usblp%d is VID=0x%4.4X, PID=0x%4.4X",
646 					usblp->minor, twoints[0], twoints[1]);
647 				break;
648 
649 			case IOCNR_SOFT_RESET:
650 				if (_IOC_DIR(cmd) != _IOC_NONE) {
651 					retval = -EINVAL;
652 					goto done;
653 				}
654 				retval = usblp_reset(usblp);
655 				break;
656 			default:
657 				retval = -ENOTTY;
658 		}
659 	else	/* old-style ioctl value */
660 		switch (cmd) {
661 
662 			case LPGETSTATUS:
663 				if ((retval = usblp_read_status(usblp, usblp->statusbuf))) {
664 					if (printk_ratelimit())
665 						printk(KERN_ERR "usblp%d:"
666 						    "failed reading printer status (%d)\n",
667 						    usblp->minor, retval);
668 					retval = -EIO;
669 					goto done;
670 				}
671 				status = *usblp->statusbuf;
672 				if (copy_to_user ((void __user *)arg, &status, sizeof(int)))
673 					retval = -EFAULT;
674 				break;
675 
676 			case LPABORT:
677 				if (arg)
678 					usblp->flags |= LP_ABORT;
679 				else
680 					usblp->flags &= ~LP_ABORT;
681 				break;
682 
683 			default:
684 				retval = -ENOTTY;
685 		}
686 
687 done:
688 	mutex_unlock (&usblp->mut);
689 	return retval;
690 }
691 
692 static struct urb *usblp_new_writeurb(struct usblp *usblp, int transfer_length)
693 {
694 	struct urb *urb;
695 	char *writebuf;
696 
697 	if ((writebuf = kmalloc(transfer_length, GFP_KERNEL)) == NULL)
698 		return NULL;
699 	if ((urb = usb_alloc_urb(0, GFP_KERNEL)) == NULL) {
700 		kfree(writebuf);
701 		return NULL;
702 	}
703 
704 	usb_fill_bulk_urb(urb, usblp->dev,
705 		usb_sndbulkpipe(usblp->dev,
706 		 usblp->protocol[usblp->current_protocol].epwrite->bEndpointAddress),
707 		writebuf, transfer_length, usblp_bulk_write, usblp);
708 	urb->transfer_flags |= URB_FREE_BUFFER;
709 
710 	return urb;
711 }
712 
713 static ssize_t usblp_write(struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
714 {
715 	struct usblp *usblp = file->private_data;
716 	struct urb *writeurb;
717 	int rv;
718 	int transfer_length;
719 	ssize_t writecount = 0;
720 
721 	if (mutex_lock_interruptible(&usblp->wmut)) {
722 		rv = -EINTR;
723 		goto raise_biglock;
724 	}
725 	if ((rv = usblp_wwait(usblp, !!(file->f_flags & O_NONBLOCK))) < 0)
726 		goto raise_wait;
727 
728 	while (writecount < count) {
729 		/*
730 		 * Step 1: Submit next block.
731 		 */
732 		if ((transfer_length = count - writecount) > USBLP_BUF_SIZE)
733 			transfer_length = USBLP_BUF_SIZE;
734 
735 		rv = -ENOMEM;
736 		if ((writeurb = usblp_new_writeurb(usblp, transfer_length)) == NULL)
737 			goto raise_urb;
738 		usb_anchor_urb(writeurb, &usblp->urbs);
739 
740 		if (copy_from_user(writeurb->transfer_buffer,
741 				   buffer + writecount, transfer_length)) {
742 			rv = -EFAULT;
743 			goto raise_badaddr;
744 		}
745 
746 		spin_lock_irq(&usblp->lock);
747 		usblp->wcomplete = 0;
748 		spin_unlock_irq(&usblp->lock);
749 		if ((rv = usb_submit_urb(writeurb, GFP_KERNEL)) < 0) {
750 			usblp->wstatus = 0;
751 			spin_lock_irq(&usblp->lock);
752 			usblp->no_paper = 0;
753 			usblp->wcomplete = 1;
754 			wake_up(&usblp->wwait);
755 			spin_unlock_irq(&usblp->lock);
756 			if (rv != -ENOMEM)
757 				rv = -EIO;
758 			goto raise_submit;
759 		}
760 
761 		/*
762 		 * Step 2: Wait for transfer to end, collect results.
763 		 */
764 		rv = usblp_wwait(usblp, !!(file->f_flags&O_NONBLOCK));
765 		if (rv < 0) {
766 			if (rv == -EAGAIN) {
767 				/* Presume that it's going to complete well. */
768 				writecount += transfer_length;
769 			}
770 			if (rv == -ENOSPC) {
771 				spin_lock_irq(&usblp->lock);
772 				usblp->no_paper = 1;	/* Mark for poll(2) */
773 				spin_unlock_irq(&usblp->lock);
774 				writecount += transfer_length;
775 			}
776 			/* Leave URB dangling, to be cleaned on close. */
777 			goto collect_error;
778 		}
779 
780 		if (usblp->wstatus < 0) {
781 			rv = -EIO;
782 			goto collect_error;
783 		}
784 		/*
785 		 * This is critical: it must be our URB, not other writer's.
786 		 * The wmut exists mainly to cover us here.
787 		 */
788 		writecount += usblp->wstatus;
789 	}
790 
791 	mutex_unlock(&usblp->wmut);
792 	return writecount;
793 
794 raise_submit:
795 raise_badaddr:
796 	usb_unanchor_urb(writeurb);
797 	usb_free_urb(writeurb);
798 raise_urb:
799 raise_wait:
800 collect_error:		/* Out of raise sequence */
801 	mutex_unlock(&usblp->wmut);
802 raise_biglock:
803 	return writecount ? writecount : rv;
804 }
805 
806 /*
807  * Notice that we fail to restart in a few cases: on EFAULT, on restart
808  * error, etc. This is the historical behaviour. In all such cases we return
809  * EIO, and applications loop in order to get the new read going.
810  */
811 static ssize_t usblp_read(struct file *file, char __user *buffer, size_t len, loff_t *ppos)
812 {
813 	struct usblp *usblp = file->private_data;
814 	ssize_t count;
815 	ssize_t avail;
816 	int rv;
817 
818 	if (!usblp->bidir)
819 		return -EINVAL;
820 
821 	rv = usblp_rwait_and_lock(usblp, !!(file->f_flags & O_NONBLOCK));
822 	if (rv < 0)
823 		return rv;
824 
825 	if ((avail = usblp->rstatus) < 0) {
826 		printk(KERN_ERR "usblp%d: error %d reading from printer\n",
827 		    usblp->minor, (int)avail);
828 		usblp_submit_read(usblp);
829 		count = -EIO;
830 		goto done;
831 	}
832 
833 	count = len < avail - usblp->readcount ? len : avail - usblp->readcount;
834 	if (count != 0 &&
835 	    copy_to_user(buffer, usblp->readbuf + usblp->readcount, count)) {
836 		count = -EFAULT;
837 		goto done;
838 	}
839 
840 	if ((usblp->readcount += count) == avail) {
841 		if (usblp_submit_read(usblp) < 0) {
842 			/* We don't want to leak USB return codes into errno. */
843 			if (count == 0)
844 				count = -EIO;
845 			goto done;
846 		}
847 	}
848 
849 done:
850 	mutex_unlock (&usblp->mut);
851 	return count;
852 }
853 
854 /*
855  * Wait for the write path to come idle.
856  * This is called under the ->wmut, so the idle path stays idle.
857  *
858  * Our write path has a peculiar property: it does not buffer like a tty,
859  * but waits for the write to succeed. This allows our ->release to bug out
860  * without waiting for writes to drain. But it obviously does not work
861  * when O_NONBLOCK is set. So, applications setting O_NONBLOCK must use
862  * select(2) or poll(2) to wait for the buffer to drain before closing.
863  * Alternatively, set blocking mode with fcntl and issue a zero-size write.
864  */
865 static int usblp_wwait(struct usblp *usblp, int nonblock)
866 {
867 	DECLARE_WAITQUEUE(waita, current);
868 	int rc;
869 	int err = 0;
870 
871 	add_wait_queue(&usblp->wwait, &waita);
872 	for (;;) {
873 		set_current_state(TASK_INTERRUPTIBLE);
874 		if (mutex_lock_interruptible(&usblp->mut)) {
875 			rc = -EINTR;
876 			break;
877 		}
878 		rc = usblp_wtest(usblp, nonblock);
879 		mutex_unlock(&usblp->mut);
880 		if (rc <= 0)
881 			break;
882 
883 		if (schedule_timeout(msecs_to_jiffies(1500)) == 0) {
884 			if (usblp->flags & LP_ABORT) {
885 				err = usblp_check_status(usblp, err);
886 				if (err == 1) {	/* Paper out */
887 					rc = -ENOSPC;
888 					break;
889 				}
890 			} else {
891 				/* Prod the printer, Gentoo#251237. */
892 				mutex_lock(&usblp->mut);
893 				usblp_read_status(usblp, usblp->statusbuf);
894 				mutex_unlock(&usblp->mut);
895 			}
896 		}
897 	}
898 	set_current_state(TASK_RUNNING);
899 	remove_wait_queue(&usblp->wwait, &waita);
900 	return rc;
901 }
902 
903 static int usblp_wtest(struct usblp *usblp, int nonblock)
904 {
905 	unsigned long flags;
906 
907 	if (!usblp->present)
908 		return -ENODEV;
909 	if (signal_pending(current))
910 		return -EINTR;
911 	spin_lock_irqsave(&usblp->lock, flags);
912 	if (usblp->wcomplete) {
913 		spin_unlock_irqrestore(&usblp->lock, flags);
914 		return 0;
915 	}
916 	spin_unlock_irqrestore(&usblp->lock, flags);
917 	if (usblp->sleeping)
918 		return -ENODEV;
919 	if (nonblock)
920 		return -EAGAIN;
921 	return 1;
922 }
923 
924 /*
925  * Wait for read bytes to become available. This probably should have been
926  * called usblp_r_lock_and_wait(), because we lock first. But it's a traditional
927  * name for functions which lock and return.
928  *
929  * We do not use wait_event_interruptible because it makes locking iffy.
930  */
931 static int usblp_rwait_and_lock(struct usblp *usblp, int nonblock)
932 {
933 	DECLARE_WAITQUEUE(waita, current);
934 	int rc;
935 
936 	add_wait_queue(&usblp->rwait, &waita);
937 	for (;;) {
938 		if (mutex_lock_interruptible(&usblp->mut)) {
939 			rc = -EINTR;
940 			break;
941 		}
942 		set_current_state(TASK_INTERRUPTIBLE);
943 		if ((rc = usblp_rtest(usblp, nonblock)) < 0) {
944 			mutex_unlock(&usblp->mut);
945 			break;
946 		}
947 		if (rc == 0)	/* Keep it locked */
948 			break;
949 		mutex_unlock(&usblp->mut);
950 		schedule();
951 	}
952 	set_current_state(TASK_RUNNING);
953 	remove_wait_queue(&usblp->rwait, &waita);
954 	return rc;
955 }
956 
957 static int usblp_rtest(struct usblp *usblp, int nonblock)
958 {
959 	unsigned long flags;
960 
961 	if (!usblp->present)
962 		return -ENODEV;
963 	if (signal_pending(current))
964 		return -EINTR;
965 	spin_lock_irqsave(&usblp->lock, flags);
966 	if (usblp->rcomplete) {
967 		spin_unlock_irqrestore(&usblp->lock, flags);
968 		return 0;
969 	}
970 	spin_unlock_irqrestore(&usblp->lock, flags);
971 	if (usblp->sleeping)
972 		return -ENODEV;
973 	if (nonblock)
974 		return -EAGAIN;
975 	return 1;
976 }
977 
978 /*
979  * Please check ->bidir and other such things outside for now.
980  */
981 static int usblp_submit_read(struct usblp *usblp)
982 {
983 	struct urb *urb;
984 	unsigned long flags;
985 	int rc;
986 
987 	rc = -ENOMEM;
988 	if ((urb = usb_alloc_urb(0, GFP_KERNEL)) == NULL)
989 		goto raise_urb;
990 
991 	usb_fill_bulk_urb(urb, usblp->dev,
992 		usb_rcvbulkpipe(usblp->dev,
993 		  usblp->protocol[usblp->current_protocol].epread->bEndpointAddress),
994 		usblp->readbuf, USBLP_BUF_SIZE_IN,
995 		usblp_bulk_read, usblp);
996 	usb_anchor_urb(urb, &usblp->urbs);
997 
998 	spin_lock_irqsave(&usblp->lock, flags);
999 	usblp->readcount = 0; /* XXX Why here? */
1000 	usblp->rcomplete = 0;
1001 	spin_unlock_irqrestore(&usblp->lock, flags);
1002 	if ((rc = usb_submit_urb(urb, GFP_KERNEL)) < 0) {
1003 		dbg("error submitting urb (%d)", rc);
1004 		spin_lock_irqsave(&usblp->lock, flags);
1005 		usblp->rstatus = rc;
1006 		usblp->rcomplete = 1;
1007 		spin_unlock_irqrestore(&usblp->lock, flags);
1008 		goto raise_submit;
1009 	}
1010 
1011 	return 0;
1012 
1013 raise_submit:
1014 	usb_unanchor_urb(urb);
1015 	usb_free_urb(urb);
1016 raise_urb:
1017 	return rc;
1018 }
1019 
1020 /*
1021  * Checks for printers that have quirks, such as requiring unidirectional
1022  * communication but reporting bidirectional; currently some HP printers
1023  * have this flaw (HP 810, 880, 895, etc.), or needing an init string
1024  * sent at each open (like some Epsons).
1025  * Returns 1 if found, 0 if not found.
1026  *
1027  * HP recommended that we use the bidirectional interface but
1028  * don't attempt any bulk IN transfers from the IN endpoint.
1029  * Here's some more detail on the problem:
1030  * The problem is not that it isn't bidirectional though. The problem
1031  * is that if you request a device ID, or status information, while
1032  * the buffers are full, the return data will end up in the print data
1033  * buffer. For example if you make sure you never request the device ID
1034  * while you are sending print data, and you don't try to query the
1035  * printer status every couple of milliseconds, you will probably be OK.
1036  */
1037 static unsigned int usblp_quirks (__u16 vendor, __u16 product)
1038 {
1039 	int i;
1040 
1041 	for (i = 0; quirk_printers[i].vendorId; i++) {
1042 		if (vendor == quirk_printers[i].vendorId &&
1043 		    product == quirk_printers[i].productId)
1044 			return quirk_printers[i].quirks;
1045  	}
1046 	return 0;
1047 }
1048 
1049 static const struct file_operations usblp_fops = {
1050 	.owner =	THIS_MODULE,
1051 	.read =		usblp_read,
1052 	.write =	usblp_write,
1053 	.poll =		usblp_poll,
1054 	.unlocked_ioctl =	usblp_ioctl,
1055 	.compat_ioctl =		usblp_ioctl,
1056 	.open =		usblp_open,
1057 	.release =	usblp_release,
1058 };
1059 
1060 static char *usblp_devnode(struct device *dev, mode_t *mode)
1061 {
1062 	return kasprintf(GFP_KERNEL, "usb/%s", dev_name(dev));
1063 }
1064 
1065 static struct usb_class_driver usblp_class = {
1066 	.name =		"lp%d",
1067 	.devnode =	usblp_devnode,
1068 	.fops =		&usblp_fops,
1069 	.minor_base =	USBLP_MINOR_BASE,
1070 };
1071 
1072 static ssize_t usblp_show_ieee1284_id(struct device *dev, struct device_attribute *attr, char *buf)
1073 {
1074 	struct usb_interface *intf = to_usb_interface(dev);
1075 	struct usblp *usblp = usb_get_intfdata (intf);
1076 
1077 	if (usblp->device_id_string[0] == 0 &&
1078 	    usblp->device_id_string[1] == 0)
1079 		return 0;
1080 
1081 	return sprintf(buf, "%s", usblp->device_id_string+2);
1082 }
1083 
1084 static DEVICE_ATTR(ieee1284_id, S_IRUGO, usblp_show_ieee1284_id, NULL);
1085 
1086 static int usblp_probe(struct usb_interface *intf,
1087 		       const struct usb_device_id *id)
1088 {
1089 	struct usb_device *dev = interface_to_usbdev (intf);
1090 	struct usblp *usblp;
1091 	int protocol;
1092 	int retval;
1093 
1094 	/* Malloc and start initializing usblp structure so we can use it
1095 	 * directly. */
1096 	usblp = kzalloc(sizeof(struct usblp), GFP_KERNEL);
1097 	if (!usblp) {
1098 		retval = -ENOMEM;
1099 		goto abort_ret;
1100 	}
1101 	usblp->dev = dev;
1102 	mutex_init(&usblp->wmut);
1103 	mutex_init (&usblp->mut);
1104 	spin_lock_init(&usblp->lock);
1105 	init_waitqueue_head(&usblp->rwait);
1106 	init_waitqueue_head(&usblp->wwait);
1107 	init_usb_anchor(&usblp->urbs);
1108 	usblp->ifnum = intf->cur_altsetting->desc.bInterfaceNumber;
1109 	usblp->intf = intf;
1110 
1111 	/* Malloc device ID string buffer to the largest expected length,
1112 	 * since we can re-query it on an ioctl and a dynamic string
1113 	 * could change in length. */
1114 	if (!(usblp->device_id_string = kmalloc(USBLP_DEVICE_ID_SIZE, GFP_KERNEL))) {
1115 		retval = -ENOMEM;
1116 		goto abort;
1117 	}
1118 
1119 	/*
1120 	 * Allocate read buffer. We somewhat wastefully
1121 	 * malloc both regardless of bidirectionality, because the
1122 	 * alternate setting can be changed later via an ioctl.
1123 	 */
1124 	if (!(usblp->readbuf = kmalloc(USBLP_BUF_SIZE_IN, GFP_KERNEL))) {
1125 		retval = -ENOMEM;
1126 		goto abort;
1127 	}
1128 
1129 	/* Allocate buffer for printer status */
1130 	usblp->statusbuf = kmalloc(STATUS_BUF_SIZE, GFP_KERNEL);
1131 	if (!usblp->statusbuf) {
1132 		retval = -ENOMEM;
1133 		goto abort;
1134 	}
1135 
1136 	/* Lookup quirks for this printer. */
1137 	usblp->quirks = usblp_quirks(
1138 		le16_to_cpu(dev->descriptor.idVendor),
1139 		le16_to_cpu(dev->descriptor.idProduct));
1140 
1141 	/* Analyze and pick initial alternate settings and endpoints. */
1142 	protocol = usblp_select_alts(usblp);
1143 	if (protocol < 0) {
1144 		dbg("incompatible printer-class device 0x%4.4X/0x%4.4X",
1145 			le16_to_cpu(dev->descriptor.idVendor),
1146 			le16_to_cpu(dev->descriptor.idProduct));
1147 		retval = -ENODEV;
1148 		goto abort;
1149 	}
1150 
1151 	/* Setup the selected alternate setting and endpoints. */
1152 	if (usblp_set_protocol(usblp, protocol) < 0) {
1153 		retval = -ENODEV;	/* ->probe isn't ->ioctl */
1154 		goto abort;
1155 	}
1156 
1157 	/* Retrieve and store the device ID string. */
1158 	usblp_cache_device_id_string(usblp);
1159 	retval = device_create_file(&intf->dev, &dev_attr_ieee1284_id);
1160 	if (retval)
1161 		goto abort_intfdata;
1162 
1163 #ifdef DEBUG
1164 	usblp_check_status(usblp, 0);
1165 #endif
1166 
1167 	usb_set_intfdata (intf, usblp);
1168 
1169 	usblp->present = 1;
1170 
1171 	retval = usb_register_dev(intf, &usblp_class);
1172 	if (retval) {
1173 		printk(KERN_ERR "usblp: Not able to get a minor"
1174 		    " (base %u, slice default): %d\n",
1175 		    USBLP_MINOR_BASE, retval);
1176 		goto abort_intfdata;
1177 	}
1178 	usblp->minor = intf->minor;
1179 	printk(KERN_INFO "usblp%d: USB %sdirectional printer dev %d "
1180 		"if %d alt %d proto %d vid 0x%4.4X pid 0x%4.4X\n",
1181 		usblp->minor, usblp->bidir ? "Bi" : "Uni", dev->devnum,
1182 		usblp->ifnum,
1183 		usblp->protocol[usblp->current_protocol].alt_setting,
1184 		usblp->current_protocol,
1185 		le16_to_cpu(usblp->dev->descriptor.idVendor),
1186 		le16_to_cpu(usblp->dev->descriptor.idProduct));
1187 
1188 	return 0;
1189 
1190 abort_intfdata:
1191 	usb_set_intfdata (intf, NULL);
1192 	device_remove_file(&intf->dev, &dev_attr_ieee1284_id);
1193 abort:
1194 	kfree(usblp->readbuf);
1195 	kfree(usblp->statusbuf);
1196 	kfree(usblp->device_id_string);
1197 	kfree(usblp);
1198 abort_ret:
1199 	return retval;
1200 }
1201 
1202 /*
1203  * We are a "new" style driver with usb_device_id table,
1204  * but our requirements are too intricate for simple match to handle.
1205  *
1206  * The "proto_bias" option may be used to specify the preferred protocol
1207  * for all USB printers (1=7/1/1, 2=7/1/2, 3=7/1/3).  If the device
1208  * supports the preferred protocol, then we bind to it.
1209  *
1210  * The best interface for us is 7/1/2, because it is compatible
1211  * with a stream of characters. If we find it, we bind to it.
1212  *
1213  * Note that the people from hpoj.sourceforge.net need to be able to
1214  * bind to 7/1/3 (MLC/1284.4), so we provide them ioctls for this purpose.
1215  *
1216  * Failing 7/1/2, we look for 7/1/3, even though it's probably not
1217  * stream-compatible, because this matches the behaviour of the old code.
1218  *
1219  * If nothing else, we bind to 7/1/1 - the unidirectional interface.
1220  */
1221 static int usblp_select_alts(struct usblp *usblp)
1222 {
1223 	struct usb_interface *if_alt;
1224 	struct usb_host_interface *ifd;
1225 	struct usb_endpoint_descriptor *epd, *epwrite, *epread;
1226 	int p, i, e;
1227 
1228 	if_alt = usblp->intf;
1229 
1230 	for (p = 0; p < USBLP_MAX_PROTOCOLS; p++)
1231 		usblp->protocol[p].alt_setting = -1;
1232 
1233 	/* Find out what we have. */
1234 	for (i = 0; i < if_alt->num_altsetting; i++) {
1235 		ifd = &if_alt->altsetting[i];
1236 
1237 		if (ifd->desc.bInterfaceClass != 7 || ifd->desc.bInterfaceSubClass != 1)
1238 			if (!(usblp->quirks & USBLP_QUIRK_BAD_CLASS))
1239 				continue;
1240 
1241 		if (ifd->desc.bInterfaceProtocol < USBLP_FIRST_PROTOCOL ||
1242 		    ifd->desc.bInterfaceProtocol > USBLP_LAST_PROTOCOL)
1243 			continue;
1244 
1245 		/* Look for bulk OUT and IN endpoints. */
1246 		epwrite = epread = NULL;
1247 		for (e = 0; e < ifd->desc.bNumEndpoints; e++) {
1248 			epd = &ifd->endpoint[e].desc;
1249 
1250 			if (usb_endpoint_is_bulk_out(epd))
1251 				if (!epwrite)
1252 					epwrite = epd;
1253 
1254 			if (usb_endpoint_is_bulk_in(epd))
1255 				if (!epread)
1256 					epread = epd;
1257 		}
1258 
1259 		/* Ignore buggy hardware without the right endpoints. */
1260 		if (!epwrite || (ifd->desc.bInterfaceProtocol > 1 && !epread))
1261 			continue;
1262 
1263 		/* Turn off reads for 7/1/1 (unidirectional) interfaces
1264 		 * and buggy bidirectional printers. */
1265 		if (ifd->desc.bInterfaceProtocol == 1) {
1266 			epread = NULL;
1267 		} else if (usblp->quirks & USBLP_QUIRK_BIDIR) {
1268 			printk(KERN_INFO "usblp%d: Disabling reads from "
1269 			    "problematic bidirectional printer\n",
1270 			    usblp->minor);
1271 			epread = NULL;
1272 		}
1273 
1274 		usblp->protocol[ifd->desc.bInterfaceProtocol].alt_setting =
1275 				ifd->desc.bAlternateSetting;
1276 		usblp->protocol[ifd->desc.bInterfaceProtocol].epwrite = epwrite;
1277 		usblp->protocol[ifd->desc.bInterfaceProtocol].epread = epread;
1278 	}
1279 
1280 	/* If our requested protocol is supported, then use it. */
1281 	if (proto_bias >= USBLP_FIRST_PROTOCOL &&
1282 	    proto_bias <= USBLP_LAST_PROTOCOL &&
1283 	    usblp->protocol[proto_bias].alt_setting != -1)
1284 		return proto_bias;
1285 
1286 	/* Ordering is important here. */
1287 	if (usblp->protocol[2].alt_setting != -1)
1288 		return 2;
1289 	if (usblp->protocol[1].alt_setting != -1)
1290 		return 1;
1291 	if (usblp->protocol[3].alt_setting != -1)
1292 		return 3;
1293 
1294 	/* If nothing is available, then don't bind to this device. */
1295 	return -1;
1296 }
1297 
1298 static int usblp_set_protocol(struct usblp *usblp, int protocol)
1299 {
1300 	int r, alts;
1301 
1302 	if (protocol < USBLP_FIRST_PROTOCOL || protocol > USBLP_LAST_PROTOCOL)
1303 		return -EINVAL;
1304 
1305 	alts = usblp->protocol[protocol].alt_setting;
1306 	if (alts < 0)
1307 		return -EINVAL;
1308 	r = usb_set_interface(usblp->dev, usblp->ifnum, alts);
1309 	if (r < 0) {
1310 		printk(KERN_ERR "usblp: can't set desired altsetting %d on interface %d\n",
1311 			alts, usblp->ifnum);
1312 		return r;
1313 	}
1314 
1315 	usblp->bidir = (usblp->protocol[protocol].epread != NULL);
1316 	usblp->current_protocol = protocol;
1317 	dbg("usblp%d set protocol %d", usblp->minor, protocol);
1318 	return 0;
1319 }
1320 
1321 /* Retrieves and caches device ID string.
1322  * Returns length, including length bytes but not null terminator.
1323  * On error, returns a negative errno value. */
1324 static int usblp_cache_device_id_string(struct usblp *usblp)
1325 {
1326 	int err, length;
1327 
1328 	err = usblp_get_id(usblp, 0, usblp->device_id_string, USBLP_DEVICE_ID_SIZE - 1);
1329 	if (err < 0) {
1330 		dbg("usblp%d: error = %d reading IEEE-1284 Device ID string",
1331 			usblp->minor, err);
1332 		usblp->device_id_string[0] = usblp->device_id_string[1] = '\0';
1333 		return -EIO;
1334 	}
1335 
1336 	/* First two bytes are length in big-endian.
1337 	 * They count themselves, and we copy them into
1338 	 * the user's buffer. */
1339 	length = be16_to_cpu(*((__be16 *)usblp->device_id_string));
1340 	if (length < 2)
1341 		length = 2;
1342 	else if (length >= USBLP_DEVICE_ID_SIZE)
1343 		length = USBLP_DEVICE_ID_SIZE - 1;
1344 	usblp->device_id_string[length] = '\0';
1345 
1346 	dbg("usblp%d Device ID string [len=%d]=\"%s\"",
1347 		usblp->minor, length, &usblp->device_id_string[2]);
1348 
1349 	return length;
1350 }
1351 
1352 static void usblp_disconnect(struct usb_interface *intf)
1353 {
1354 	struct usblp *usblp = usb_get_intfdata (intf);
1355 
1356 	usb_deregister_dev(intf, &usblp_class);
1357 
1358 	if (!usblp || !usblp->dev) {
1359 		dev_err(&intf->dev, "bogus disconnect\n");
1360 		BUG ();
1361 	}
1362 
1363 	device_remove_file(&intf->dev, &dev_attr_ieee1284_id);
1364 
1365 	mutex_lock (&usblp_mutex);
1366 	mutex_lock (&usblp->mut);
1367 	usblp->present = 0;
1368 	wake_up(&usblp->wwait);
1369 	wake_up(&usblp->rwait);
1370 	usb_set_intfdata (intf, NULL);
1371 
1372 	usblp_unlink_urbs(usblp);
1373 	mutex_unlock (&usblp->mut);
1374 
1375 	if (!usblp->used)
1376 		usblp_cleanup (usblp);
1377 	mutex_unlock (&usblp_mutex);
1378 }
1379 
1380 static int usblp_suspend (struct usb_interface *intf, pm_message_t message)
1381 {
1382 	struct usblp *usblp = usb_get_intfdata (intf);
1383 
1384 	/* we take no more IO */
1385 	usblp->sleeping = 1;
1386 	usblp_unlink_urbs(usblp);
1387 #if 0 /* XXX Do we want this? What if someone is reading, should we fail? */
1388 	/* not strictly necessary, but just in case */
1389 	wake_up(&usblp->wwait);
1390 	wake_up(&usblp->rwait);
1391 #endif
1392 
1393 	return 0;
1394 }
1395 
1396 static int usblp_resume (struct usb_interface *intf)
1397 {
1398 	struct usblp *usblp = usb_get_intfdata (intf);
1399 	int r;
1400 
1401 	usblp->sleeping = 0;
1402 	r = handle_bidir (usblp);
1403 
1404 	return r;
1405 }
1406 
1407 static struct usb_device_id usblp_ids [] = {
1408 	{ USB_DEVICE_INFO(7, 1, 1) },
1409 	{ USB_DEVICE_INFO(7, 1, 2) },
1410 	{ USB_DEVICE_INFO(7, 1, 3) },
1411 	{ USB_INTERFACE_INFO(7, 1, 1) },
1412 	{ USB_INTERFACE_INFO(7, 1, 2) },
1413 	{ USB_INTERFACE_INFO(7, 1, 3) },
1414 	{ USB_DEVICE(0x04b8, 0x0202) },	/* Seiko Epson Receipt Printer M129C */
1415 	{ }						/* Terminating entry */
1416 };
1417 
1418 MODULE_DEVICE_TABLE (usb, usblp_ids);
1419 
1420 static struct usb_driver usblp_driver = {
1421 	.name =		"usblp",
1422 	.probe =	usblp_probe,
1423 	.disconnect =	usblp_disconnect,
1424 	.suspend =	usblp_suspend,
1425 	.resume =	usblp_resume,
1426 	.id_table =	usblp_ids,
1427 	.supports_autosuspend =	1,
1428 };
1429 
1430 static int __init usblp_init(void)
1431 {
1432 	return usb_register(&usblp_driver);
1433 }
1434 
1435 static void __exit usblp_exit(void)
1436 {
1437 	usb_deregister(&usblp_driver);
1438 }
1439 
1440 module_init(usblp_init);
1441 module_exit(usblp_exit);
1442 
1443 MODULE_AUTHOR( DRIVER_AUTHOR );
1444 MODULE_DESCRIPTION( DRIVER_DESC );
1445 module_param(proto_bias, int, S_IRUGO | S_IWUSR);
1446 MODULE_PARM_DESC(proto_bias, "Favourite protocol number");
1447 MODULE_LICENSE("GPL");
1448