xref: /openbmc/linux/drivers/usb/class/usblp.c (revision 1e013ff7)
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * usblp.c
4  *
5  * Copyright (c) 1999 Michael Gee	<michael@linuxspecific.com>
6  * Copyright (c) 1999 Pavel Machek	<pavel@ucw.cz>
7  * Copyright (c) 2000 Randy Dunlap	<rdunlap@xenotime.net>
8  * Copyright (c) 2000 Vojtech Pavlik	<vojtech@suse.cz>
9  # Copyright (c) 2001 Pete Zaitcev	<zaitcev@redhat.com>
10  # Copyright (c) 2001 David Paschal	<paschal@rcsis.com>
11  * Copyright (c) 2006 Oliver Neukum	<oliver@neukum.name>
12  *
13  * USB Printer Device Class driver for USB printers and printer cables
14  *
15  * Sponsored by SuSE
16  *
17  * ChangeLog:
18  *	v0.1 - thorough cleaning, URBification, almost a rewrite
19  *	v0.2 - some more cleanups
20  *	v0.3 - cleaner again, waitqueue fixes
21  *	v0.4 - fixes in unidirectional mode
22  *	v0.5 - add DEVICE_ID string support
23  *	v0.6 - never time out
24  *	v0.7 - fixed bulk-IN read and poll (David Paschal)
25  *	v0.8 - add devfs support
26  *	v0.9 - fix unplug-while-open paths
27  *	v0.10- remove sleep_on, fix error on oom (oliver@neukum.org)
28  *	v0.11 - add proto_bias option (Pete Zaitcev)
29  *	v0.12 - add hpoj.sourceforge.net ioctls (David Paschal)
30  *	v0.13 - alloc space for statusbuf (<status> not on stack);
31  *		use usb_alloc_coherent() for read buf & write buf;
32  *      none  - Maintained in Linux kernel after v0.13
33  */
34 
35 #include <linux/module.h>
36 #include <linux/kernel.h>
37 #include <linux/sched/signal.h>
38 #include <linux/signal.h>
39 #include <linux/poll.h>
40 #include <linux/slab.h>
41 #include <linux/lp.h>
42 #include <linux/mutex.h>
43 #undef DEBUG
44 #include <linux/usb.h>
45 #include <linux/usb/ch9.h>
46 #include <linux/ratelimit.h>
47 
48 /*
49  * Version Information
50  */
51 #define DRIVER_AUTHOR "Michael Gee, Pavel Machek, Vojtech Pavlik, Randy Dunlap, Pete Zaitcev, David Paschal"
52 #define DRIVER_DESC "USB Printer Device Class driver"
53 
54 #define USBLP_BUF_SIZE		8192
55 #define USBLP_BUF_SIZE_IN	1024
56 #define USBLP_DEVICE_ID_SIZE	1024
57 
58 /* ioctls: */
59 #define IOCNR_GET_DEVICE_ID		1
60 #define IOCNR_GET_PROTOCOLS		2
61 #define IOCNR_SET_PROTOCOL		3
62 #define IOCNR_HP_SET_CHANNEL		4
63 #define IOCNR_GET_BUS_ADDRESS		5
64 #define IOCNR_GET_VID_PID		6
65 #define IOCNR_SOFT_RESET		7
66 /* Get device_id string: */
67 #define LPIOC_GET_DEVICE_ID(len) _IOC(_IOC_READ, 'P', IOCNR_GET_DEVICE_ID, len)
68 /* The following ioctls were added for http://hpoj.sourceforge.net:
69  * Get two-int array:
70  * [0]=current protocol
71  *     (1=USB_CLASS_PRINTER/1/1, 2=USB_CLASS_PRINTER/1/2,
72  *         3=USB_CLASS_PRINTER/1/3),
73  * [1]=supported protocol mask (mask&(1<<n)!=0 means
74  *     USB_CLASS_PRINTER/1/n supported):
75  */
76 #define LPIOC_GET_PROTOCOLS(len) _IOC(_IOC_READ, 'P', IOCNR_GET_PROTOCOLS, len)
77 /*
78  * Set protocol
79  *     (arg: 1=USB_CLASS_PRINTER/1/1, 2=USB_CLASS_PRINTER/1/2,
80  *         3=USB_CLASS_PRINTER/1/3):
81  */
82 #define LPIOC_SET_PROTOCOL _IOC(_IOC_WRITE, 'P', IOCNR_SET_PROTOCOL, 0)
83 /* Set channel number (HP Vendor-specific command): */
84 #define LPIOC_HP_SET_CHANNEL _IOC(_IOC_WRITE, 'P', IOCNR_HP_SET_CHANNEL, 0)
85 /* Get two-int array: [0]=bus number, [1]=device address: */
86 #define LPIOC_GET_BUS_ADDRESS(len) _IOC(_IOC_READ, 'P', IOCNR_GET_BUS_ADDRESS, len)
87 /* Get two-int array: [0]=vendor ID, [1]=product ID: */
88 #define LPIOC_GET_VID_PID(len) _IOC(_IOC_READ, 'P', IOCNR_GET_VID_PID, len)
89 /* Perform class specific soft reset */
90 #define LPIOC_SOFT_RESET _IOC(_IOC_NONE, 'P', IOCNR_SOFT_RESET, 0);
91 
92 /*
93  * A DEVICE_ID string may include the printer's serial number.
94  * It should end with a semi-colon (';').
95  * An example from an HP 970C DeskJet printer is (this is one long string,
96  * with the serial number changed):
97 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:                    ;
98  */
99 
100 /*
101  * USB Printer Requests
102  */
103 
104 #define USBLP_REQ_GET_ID			0x00
105 #define USBLP_REQ_GET_STATUS			0x01
106 #define USBLP_REQ_RESET				0x02
107 #define USBLP_REQ_HP_CHANNEL_CHANGE_REQUEST	0x00	/* HP Vendor-specific */
108 
109 #define USBLP_MINORS		16
110 #define USBLP_MINOR_BASE	0
111 
112 #define USBLP_CTL_TIMEOUT	5000			/* 5 seconds */
113 
114 #define USBLP_FIRST_PROTOCOL	1
115 #define USBLP_LAST_PROTOCOL	3
116 #define USBLP_MAX_PROTOCOLS	(USBLP_LAST_PROTOCOL+1)
117 
118 /*
119  * some arbitrary status buffer size;
120  * need a status buffer that is allocated via kmalloc(), not on stack
121  */
122 #define STATUS_BUF_SIZE		8
123 
124 /*
125  * Locks down the locking order:
126  * ->wmut locks wstatus.
127  * ->mut locks the whole usblp, except [rw]complete, and thus, by indirection,
128  * [rw]status. We only touch status when we know the side idle.
129  * ->lock locks what interrupt accesses.
130  */
131 struct usblp {
132 	struct usb_device	*dev;			/* USB device */
133 	struct mutex		wmut;
134 	struct mutex		mut;
135 	spinlock_t		lock;		/* locks rcomplete, wcomplete */
136 	char			*readbuf;		/* read transfer_buffer */
137 	char			*statusbuf;		/* status transfer_buffer */
138 	struct usb_anchor	urbs;
139 	wait_queue_head_t	rwait, wwait;
140 	int			readcount;		/* Counter for reads */
141 	int			ifnum;			/* Interface number */
142 	struct usb_interface	*intf;			/* The interface */
143 	/*
144 	 * Alternate-setting numbers and endpoints for each protocol
145 	 * (USB_CLASS_PRINTER/1/{index=1,2,3}) that the device supports:
146 	 */
147 	struct {
148 		int				alt_setting;
149 		struct usb_endpoint_descriptor	*epwrite;
150 		struct usb_endpoint_descriptor	*epread;
151 	}			protocol[USBLP_MAX_PROTOCOLS];
152 	int			current_protocol;
153 	int			minor;			/* minor number of device */
154 	int			wcomplete, rcomplete;
155 	int			wstatus;	/* bytes written or error */
156 	int			rstatus;	/* bytes ready or error */
157 	unsigned int		quirks;			/* quirks flags */
158 	unsigned int		flags;			/* mode flags */
159 	unsigned char		used;			/* True if open */
160 	unsigned char		present;		/* True if not disconnected */
161 	unsigned char		bidir;			/* interface is bidirectional */
162 	unsigned char		no_paper;		/* Paper Out happened */
163 	unsigned char		*device_id_string;	/* IEEE 1284 DEVICE ID string (ptr) */
164 							/* first 2 bytes are (big-endian) length */
165 };
166 
167 #ifdef DEBUG
168 static void usblp_dump(struct usblp *usblp)
169 {
170 	struct device *dev = &usblp->intf->dev;
171 	int p;
172 
173 	dev_dbg(dev, "usblp=0x%p\n", usblp);
174 	dev_dbg(dev, "dev=0x%p\n", usblp->dev);
175 	dev_dbg(dev, "present=%d\n", usblp->present);
176 	dev_dbg(dev, "readbuf=0x%p\n", usblp->readbuf);
177 	dev_dbg(dev, "readcount=%d\n", usblp->readcount);
178 	dev_dbg(dev, "ifnum=%d\n", usblp->ifnum);
179 	for (p = USBLP_FIRST_PROTOCOL; p <= USBLP_LAST_PROTOCOL; p++) {
180 		dev_dbg(dev, "protocol[%d].alt_setting=%d\n", p,
181 			usblp->protocol[p].alt_setting);
182 		dev_dbg(dev, "protocol[%d].epwrite=%p\n", p,
183 			usblp->protocol[p].epwrite);
184 		dev_dbg(dev, "protocol[%d].epread=%p\n", p,
185 			usblp->protocol[p].epread);
186 	}
187 	dev_dbg(dev, "current_protocol=%d\n", usblp->current_protocol);
188 	dev_dbg(dev, "minor=%d\n", usblp->minor);
189 	dev_dbg(dev, "wstatus=%d\n", usblp->wstatus);
190 	dev_dbg(dev, "rstatus=%d\n", usblp->rstatus);
191 	dev_dbg(dev, "quirks=%d\n", usblp->quirks);
192 	dev_dbg(dev, "used=%d\n", usblp->used);
193 	dev_dbg(dev, "bidir=%d\n", usblp->bidir);
194 	dev_dbg(dev, "device_id_string=\"%s\"\n",
195 		usblp->device_id_string ?
196 			usblp->device_id_string + 2 :
197 			(unsigned char *)"(null)");
198 }
199 #endif
200 
201 /* Quirks: various printer quirks are handled by this table & its flags. */
202 
203 struct quirk_printer_struct {
204 	__u16 vendorId;
205 	__u16 productId;
206 	unsigned int quirks;
207 };
208 
209 #define USBLP_QUIRK_BIDIR	0x1	/* reports bidir but requires unidirectional mode (no INs/reads) */
210 #define USBLP_QUIRK_USB_INIT	0x2	/* needs vendor USB init string */
211 #define USBLP_QUIRK_BAD_CLASS	0x4	/* descriptor uses vendor-specific Class or SubClass */
212 
213 static const struct quirk_printer_struct quirk_printers[] = {
214 	{ 0x03f0, 0x0004, USBLP_QUIRK_BIDIR }, /* HP DeskJet 895C */
215 	{ 0x03f0, 0x0104, USBLP_QUIRK_BIDIR }, /* HP DeskJet 880C */
216 	{ 0x03f0, 0x0204, USBLP_QUIRK_BIDIR }, /* HP DeskJet 815C */
217 	{ 0x03f0, 0x0304, USBLP_QUIRK_BIDIR }, /* HP DeskJet 810C/812C */
218 	{ 0x03f0, 0x0404, USBLP_QUIRK_BIDIR }, /* HP DeskJet 830C */
219 	{ 0x03f0, 0x0504, USBLP_QUIRK_BIDIR }, /* HP DeskJet 885C */
220 	{ 0x03f0, 0x0604, USBLP_QUIRK_BIDIR }, /* HP DeskJet 840C */
221 	{ 0x03f0, 0x0804, USBLP_QUIRK_BIDIR }, /* HP DeskJet 816C */
222 	{ 0x03f0, 0x1104, USBLP_QUIRK_BIDIR }, /* HP Deskjet 959C */
223 	{ 0x0409, 0xefbe, USBLP_QUIRK_BIDIR }, /* NEC Picty900 (HP OEM) */
224 	{ 0x0409, 0xbef4, USBLP_QUIRK_BIDIR }, /* NEC Picty760 (HP OEM) */
225 	{ 0x0409, 0xf0be, USBLP_QUIRK_BIDIR }, /* NEC Picty920 (HP OEM) */
226 	{ 0x0409, 0xf1be, USBLP_QUIRK_BIDIR }, /* NEC Picty800 (HP OEM) */
227 	{ 0x0482, 0x0010, USBLP_QUIRK_BIDIR }, /* Kyocera Mita FS 820, by zut <kernel@zut.de> */
228 	{ 0x04f9, 0x000d, USBLP_QUIRK_BIDIR }, /* Brother Industries, Ltd HL-1440 Laser Printer */
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 	retval = usb_control_msg(usblp->dev,
262 		dir ? usb_rcvctrlpipe(usblp->dev, 0) : usb_sndctrlpipe(usblp->dev, 0),
263 		request, type | dir | recip, value, index, buf, len, USBLP_CTL_TIMEOUT);
264 	dev_dbg(&usblp->intf->dev,
265 		"usblp_control_msg: rq: 0x%02x dir: %d recip: %d value: %d idx: %d len: %#x result: %d\n",
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 static int usblp_hp_channel_change_request(struct usblp *usblp, int channel, u8 *new_channel)
278 {
279 	u8 *buf;
280 	int ret;
281 
282 	buf = kzalloc(1, GFP_KERNEL);
283 	if (!buf)
284 		return -ENOMEM;
285 
286 	ret = usblp_ctrl_msg(usblp, USBLP_REQ_HP_CHANNEL_CHANGE_REQUEST,
287 			USB_TYPE_VENDOR, USB_DIR_IN, USB_RECIP_INTERFACE,
288 			channel, buf, 1);
289 	if (ret == 0)
290 		*new_channel = buf[0];
291 
292 	kfree(buf);
293 
294 	return ret;
295 }
296 
297 /*
298  * See the description for usblp_select_alts() below for the usage
299  * explanation.  Look into your /sys/kernel/debug/usb/devices and dmesg in
300  * case of any trouble.
301  */
302 static int proto_bias = -1;
303 
304 /*
305  * URB callback.
306  */
307 
308 static void usblp_bulk_read(struct urb *urb)
309 {
310 	struct usblp *usblp = urb->context;
311 	int status = urb->status;
312 	unsigned long flags;
313 
314 	if (usblp->present && usblp->used) {
315 		if (status)
316 			printk(KERN_WARNING "usblp%d: "
317 			    "nonzero read bulk status received: %d\n",
318 			    usblp->minor, status);
319 	}
320 	spin_lock_irqsave(&usblp->lock, flags);
321 	if (status < 0)
322 		usblp->rstatus = status;
323 	else
324 		usblp->rstatus = urb->actual_length;
325 	usblp->rcomplete = 1;
326 	wake_up(&usblp->rwait);
327 	spin_unlock_irqrestore(&usblp->lock, flags);
328 
329 	usb_free_urb(urb);
330 }
331 
332 static void usblp_bulk_write(struct urb *urb)
333 {
334 	struct usblp *usblp = urb->context;
335 	int status = urb->status;
336 	unsigned long flags;
337 
338 	if (usblp->present && usblp->used) {
339 		if (status)
340 			printk(KERN_WARNING "usblp%d: "
341 			    "nonzero write bulk status received: %d\n",
342 			    usblp->minor, status);
343 	}
344 	spin_lock_irqsave(&usblp->lock, flags);
345 	if (status < 0)
346 		usblp->wstatus = status;
347 	else
348 		usblp->wstatus = urb->actual_length;
349 	usblp->no_paper = 0;
350 	usblp->wcomplete = 1;
351 	wake_up(&usblp->wwait);
352 	spin_unlock_irqrestore(&usblp->lock, flags);
353 
354 	usb_free_urb(urb);
355 }
356 
357 /*
358  * Get and print printer errors.
359  */
360 
361 static const char *usblp_messages[] = { "ok", "out of paper", "off-line", "on fire" };
362 
363 static int usblp_check_status(struct usblp *usblp, int err)
364 {
365 	unsigned char status, newerr = 0;
366 	int error;
367 
368 	mutex_lock(&usblp->mut);
369 	if ((error = usblp_read_status(usblp, usblp->statusbuf)) < 0) {
370 		mutex_unlock(&usblp->mut);
371 		printk_ratelimited(KERN_ERR
372 				"usblp%d: error %d reading printer status\n",
373 				usblp->minor, error);
374 		return 0;
375 	}
376 	status = *usblp->statusbuf;
377 	mutex_unlock(&usblp->mut);
378 
379 	if (~status & LP_PERRORP)
380 		newerr = 3;
381 	if (status & LP_POUTPA)
382 		newerr = 1;
383 	if (~status & LP_PSELECD)
384 		newerr = 2;
385 
386 	if (newerr != err) {
387 		printk(KERN_INFO "usblp%d: %s\n",
388 		   usblp->minor, usblp_messages[newerr]);
389 	}
390 
391 	return newerr;
392 }
393 
394 static int handle_bidir(struct usblp *usblp)
395 {
396 	if (usblp->bidir && usblp->used) {
397 		if (usblp_submit_read(usblp) < 0)
398 			return -EIO;
399 	}
400 	return 0;
401 }
402 
403 /*
404  * File op functions.
405  */
406 
407 static int usblp_open(struct inode *inode, struct file *file)
408 {
409 	int minor = iminor(inode);
410 	struct usblp *usblp;
411 	struct usb_interface *intf;
412 	int retval;
413 
414 	if (minor < 0)
415 		return -ENODEV;
416 
417 	mutex_lock(&usblp_mutex);
418 
419 	retval = -ENODEV;
420 	intf = usb_find_interface(&usblp_driver, minor);
421 	if (!intf)
422 		goto out;
423 	usblp = usb_get_intfdata(intf);
424 	if (!usblp || !usblp->dev || !usblp->present)
425 		goto out;
426 
427 	retval = -EBUSY;
428 	if (usblp->used)
429 		goto out;
430 
431 	/*
432 	 * We do not implement LP_ABORTOPEN/LPABORTOPEN for two reasons:
433 	 *  - We do not want persistent state which close(2) does not clear
434 	 *  - It is not used anyway, according to CUPS people
435 	 */
436 
437 	retval = usb_autopm_get_interface(intf);
438 	if (retval < 0)
439 		goto out;
440 	usblp->used = 1;
441 	file->private_data = usblp;
442 
443 	usblp->wcomplete = 1; /* we begin writeable */
444 	usblp->wstatus = 0;
445 	usblp->rcomplete = 0;
446 
447 	if (handle_bidir(usblp) < 0) {
448 		usb_autopm_put_interface(intf);
449 		usblp->used = 0;
450 		file->private_data = NULL;
451 		retval = -EIO;
452 	}
453 out:
454 	mutex_unlock(&usblp_mutex);
455 	return retval;
456 }
457 
458 static void usblp_cleanup(struct usblp *usblp)
459 {
460 	printk(KERN_INFO "usblp%d: removed\n", usblp->minor);
461 
462 	kfree(usblp->readbuf);
463 	kfree(usblp->device_id_string);
464 	kfree(usblp->statusbuf);
465 	usb_put_intf(usblp->intf);
466 	kfree(usblp);
467 }
468 
469 static void usblp_unlink_urbs(struct usblp *usblp)
470 {
471 	usb_kill_anchored_urbs(&usblp->urbs);
472 }
473 
474 static int usblp_release(struct inode *inode, struct file *file)
475 {
476 	struct usblp *usblp = file->private_data;
477 
478 	usblp->flags &= ~LP_ABORT;
479 
480 	mutex_lock(&usblp_mutex);
481 	usblp->used = 0;
482 	if (usblp->present)
483 		usblp_unlink_urbs(usblp);
484 
485 	usb_autopm_put_interface(usblp->intf);
486 
487 	if (!usblp->present)		/* finish cleanup from disconnect */
488 		usblp_cleanup(usblp);	/* any URBs must be dead */
489 
490 	mutex_unlock(&usblp_mutex);
491 	return 0;
492 }
493 
494 /* No kernel lock - fine */
495 static __poll_t usblp_poll(struct file *file, struct poll_table_struct *wait)
496 {
497 	__poll_t ret;
498 	unsigned long flags;
499 
500 	struct usblp *usblp = file->private_data;
501 	/* Should we check file->f_mode & FMODE_WRITE before poll_wait()? */
502 	poll_wait(file, &usblp->rwait, wait);
503 	poll_wait(file, &usblp->wwait, wait);
504 	spin_lock_irqsave(&usblp->lock, flags);
505 	ret = ((usblp->bidir && usblp->rcomplete) ? EPOLLIN  | EPOLLRDNORM : 0) |
506 	   ((usblp->no_paper || usblp->wcomplete) ? EPOLLOUT | EPOLLWRNORM : 0);
507 	spin_unlock_irqrestore(&usblp->lock, flags);
508 	return ret;
509 }
510 
511 static long usblp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
512 {
513 	struct usblp *usblp = file->private_data;
514 	int length, err, i;
515 	unsigned char newChannel;
516 	int status;
517 	int twoints[2];
518 	int retval = 0;
519 
520 	mutex_lock(&usblp->mut);
521 	if (!usblp->present) {
522 		retval = -ENODEV;
523 		goto done;
524 	}
525 
526 	dev_dbg(&usblp->intf->dev,
527 		"usblp_ioctl: cmd=0x%x (%c nr=%d len=%d dir=%d)\n", cmd,
528 		_IOC_TYPE(cmd), _IOC_NR(cmd), _IOC_SIZE(cmd), _IOC_DIR(cmd));
529 
530 	if (_IOC_TYPE(cmd) == 'P')	/* new-style ioctl number */
531 
532 		switch (_IOC_NR(cmd)) {
533 
534 		case IOCNR_GET_DEVICE_ID: /* get the DEVICE_ID string */
535 			if (_IOC_DIR(cmd) != _IOC_READ) {
536 				retval = -EINVAL;
537 				goto done;
538 			}
539 
540 			length = usblp_cache_device_id_string(usblp);
541 			if (length < 0) {
542 				retval = length;
543 				goto done;
544 			}
545 			if (length > _IOC_SIZE(cmd))
546 				length = _IOC_SIZE(cmd); /* truncate */
547 
548 			if (copy_to_user((void __user *) arg,
549 					usblp->device_id_string,
550 					(unsigned long) length)) {
551 				retval = -EFAULT;
552 				goto done;
553 			}
554 
555 			break;
556 
557 		case IOCNR_GET_PROTOCOLS:
558 			if (_IOC_DIR(cmd) != _IOC_READ ||
559 			    _IOC_SIZE(cmd) < sizeof(twoints)) {
560 				retval = -EINVAL;
561 				goto done;
562 			}
563 
564 			twoints[0] = usblp->current_protocol;
565 			twoints[1] = 0;
566 			for (i = USBLP_FIRST_PROTOCOL;
567 			     i <= USBLP_LAST_PROTOCOL; i++) {
568 				if (usblp->protocol[i].alt_setting >= 0)
569 					twoints[1] |= (1<<i);
570 			}
571 
572 			if (copy_to_user((void __user *)arg,
573 					(unsigned char *)twoints,
574 					sizeof(twoints))) {
575 				retval = -EFAULT;
576 				goto done;
577 			}
578 
579 			break;
580 
581 		case IOCNR_SET_PROTOCOL:
582 			if (_IOC_DIR(cmd) != _IOC_WRITE) {
583 				retval = -EINVAL;
584 				goto done;
585 			}
586 
587 #ifdef DEBUG
588 			if (arg == -10) {
589 				usblp_dump(usblp);
590 				break;
591 			}
592 #endif
593 
594 			usblp_unlink_urbs(usblp);
595 			retval = usblp_set_protocol(usblp, arg);
596 			if (retval < 0) {
597 				usblp_set_protocol(usblp,
598 					usblp->current_protocol);
599 			}
600 			break;
601 
602 		case IOCNR_HP_SET_CHANNEL:
603 			if (_IOC_DIR(cmd) != _IOC_WRITE ||
604 			    le16_to_cpu(usblp->dev->descriptor.idVendor) != 0x03F0 ||
605 			    usblp->quirks & USBLP_QUIRK_BIDIR) {
606 				retval = -EINVAL;
607 				goto done;
608 			}
609 
610 			err = usblp_hp_channel_change_request(usblp,
611 				arg, &newChannel);
612 			if (err < 0) {
613 				dev_err(&usblp->dev->dev,
614 					"usblp%d: error = %d setting "
615 					"HP channel\n",
616 					usblp->minor, err);
617 				retval = -EIO;
618 				goto done;
619 			}
620 
621 			dev_dbg(&usblp->intf->dev,
622 				"usblp%d requested/got HP channel %ld/%d\n",
623 				usblp->minor, arg, newChannel);
624 			break;
625 
626 		case IOCNR_GET_BUS_ADDRESS:
627 			if (_IOC_DIR(cmd) != _IOC_READ ||
628 			    _IOC_SIZE(cmd) < sizeof(twoints)) {
629 				retval = -EINVAL;
630 				goto done;
631 			}
632 
633 			twoints[0] = usblp->dev->bus->busnum;
634 			twoints[1] = usblp->dev->devnum;
635 			if (copy_to_user((void __user *)arg,
636 					(unsigned char *)twoints,
637 					sizeof(twoints))) {
638 				retval = -EFAULT;
639 				goto done;
640 			}
641 
642 			dev_dbg(&usblp->intf->dev,
643 				"usblp%d is bus=%d, device=%d\n",
644 				usblp->minor, twoints[0], twoints[1]);
645 			break;
646 
647 		case IOCNR_GET_VID_PID:
648 			if (_IOC_DIR(cmd) != _IOC_READ ||
649 			    _IOC_SIZE(cmd) < sizeof(twoints)) {
650 				retval = -EINVAL;
651 				goto done;
652 			}
653 
654 			twoints[0] = le16_to_cpu(usblp->dev->descriptor.idVendor);
655 			twoints[1] = le16_to_cpu(usblp->dev->descriptor.idProduct);
656 			if (copy_to_user((void __user *)arg,
657 					(unsigned char *)twoints,
658 					sizeof(twoints))) {
659 				retval = -EFAULT;
660 				goto done;
661 			}
662 
663 			dev_dbg(&usblp->intf->dev,
664 				"usblp%d is VID=0x%4.4X, PID=0x%4.4X\n",
665 				usblp->minor, twoints[0], twoints[1]);
666 			break;
667 
668 		case IOCNR_SOFT_RESET:
669 			if (_IOC_DIR(cmd) != _IOC_NONE) {
670 				retval = -EINVAL;
671 				goto done;
672 			}
673 			retval = usblp_reset(usblp);
674 			break;
675 		default:
676 			retval = -ENOTTY;
677 		}
678 	else	/* old-style ioctl value */
679 		switch (cmd) {
680 
681 		case LPGETSTATUS:
682 			retval = usblp_read_status(usblp, usblp->statusbuf);
683 			if (retval) {
684 				printk_ratelimited(KERN_ERR "usblp%d:"
685 					    "failed reading printer status (%d)\n",
686 					    usblp->minor, retval);
687 				retval = -EIO;
688 				goto done;
689 			}
690 			status = *usblp->statusbuf;
691 			if (copy_to_user((void __user *)arg, &status, sizeof(int)))
692 				retval = -EFAULT;
693 			break;
694 
695 		case LPABORT:
696 			if (arg)
697 				usblp->flags |= LP_ABORT;
698 			else
699 				usblp->flags &= ~LP_ABORT;
700 			break;
701 
702 		default:
703 			retval = -ENOTTY;
704 		}
705 
706 done:
707 	mutex_unlock(&usblp->mut);
708 	return retval;
709 }
710 
711 static struct urb *usblp_new_writeurb(struct usblp *usblp, int transfer_length)
712 {
713 	struct urb *urb;
714 	char *writebuf;
715 
716 	writebuf = kmalloc(transfer_length, GFP_KERNEL);
717 	if (writebuf == NULL)
718 		return NULL;
719 	urb = usb_alloc_urb(0, GFP_KERNEL);
720 	if (urb == NULL) {
721 		kfree(writebuf);
722 		return NULL;
723 	}
724 
725 	usb_fill_bulk_urb(urb, usblp->dev,
726 		usb_sndbulkpipe(usblp->dev,
727 		 usblp->protocol[usblp->current_protocol].epwrite->bEndpointAddress),
728 		writebuf, transfer_length, usblp_bulk_write, usblp);
729 	urb->transfer_flags |= URB_FREE_BUFFER;
730 
731 	return urb;
732 }
733 
734 static ssize_t usblp_write(struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
735 {
736 	struct usblp *usblp = file->private_data;
737 	struct urb *writeurb;
738 	int rv;
739 	int transfer_length;
740 	ssize_t writecount = 0;
741 
742 	if (mutex_lock_interruptible(&usblp->wmut)) {
743 		rv = -EINTR;
744 		goto raise_biglock;
745 	}
746 	if ((rv = usblp_wwait(usblp, !!(file->f_flags & O_NONBLOCK))) < 0)
747 		goto raise_wait;
748 
749 	while (writecount < count) {
750 		/*
751 		 * Step 1: Submit next block.
752 		 */
753 		if ((transfer_length = count - writecount) > USBLP_BUF_SIZE)
754 			transfer_length = USBLP_BUF_SIZE;
755 
756 		rv = -ENOMEM;
757 		writeurb = usblp_new_writeurb(usblp, transfer_length);
758 		if (writeurb == NULL)
759 			goto raise_urb;
760 		usb_anchor_urb(writeurb, &usblp->urbs);
761 
762 		if (copy_from_user(writeurb->transfer_buffer,
763 				   buffer + writecount, transfer_length)) {
764 			rv = -EFAULT;
765 			goto raise_badaddr;
766 		}
767 
768 		spin_lock_irq(&usblp->lock);
769 		usblp->wcomplete = 0;
770 		spin_unlock_irq(&usblp->lock);
771 		if ((rv = usb_submit_urb(writeurb, GFP_KERNEL)) < 0) {
772 			usblp->wstatus = 0;
773 			spin_lock_irq(&usblp->lock);
774 			usblp->no_paper = 0;
775 			usblp->wcomplete = 1;
776 			wake_up(&usblp->wwait);
777 			spin_unlock_irq(&usblp->lock);
778 			if (rv != -ENOMEM)
779 				rv = -EIO;
780 			goto raise_submit;
781 		}
782 
783 		/*
784 		 * Step 2: Wait for transfer to end, collect results.
785 		 */
786 		rv = usblp_wwait(usblp, !!(file->f_flags&O_NONBLOCK));
787 		if (rv < 0) {
788 			if (rv == -EAGAIN) {
789 				/* Presume that it's going to complete well. */
790 				writecount += transfer_length;
791 			}
792 			if (rv == -ENOSPC) {
793 				spin_lock_irq(&usblp->lock);
794 				usblp->no_paper = 1;	/* Mark for poll(2) */
795 				spin_unlock_irq(&usblp->lock);
796 				writecount += transfer_length;
797 			}
798 			/* Leave URB dangling, to be cleaned on close. */
799 			goto collect_error;
800 		}
801 
802 		if (usblp->wstatus < 0) {
803 			rv = -EIO;
804 			goto collect_error;
805 		}
806 		/*
807 		 * This is critical: it must be our URB, not other writer's.
808 		 * The wmut exists mainly to cover us here.
809 		 */
810 		writecount += usblp->wstatus;
811 	}
812 
813 	mutex_unlock(&usblp->wmut);
814 	return writecount;
815 
816 raise_submit:
817 raise_badaddr:
818 	usb_unanchor_urb(writeurb);
819 	usb_free_urb(writeurb);
820 raise_urb:
821 raise_wait:
822 collect_error:		/* Out of raise sequence */
823 	mutex_unlock(&usblp->wmut);
824 raise_biglock:
825 	return writecount ? writecount : rv;
826 }
827 
828 /*
829  * Notice that we fail to restart in a few cases: on EFAULT, on restart
830  * error, etc. This is the historical behaviour. In all such cases we return
831  * EIO, and applications loop in order to get the new read going.
832  */
833 static ssize_t usblp_read(struct file *file, char __user *buffer, size_t len, loff_t *ppos)
834 {
835 	struct usblp *usblp = file->private_data;
836 	ssize_t count;
837 	ssize_t avail;
838 	int rv;
839 
840 	if (!usblp->bidir)
841 		return -EINVAL;
842 
843 	rv = usblp_rwait_and_lock(usblp, !!(file->f_flags & O_NONBLOCK));
844 	if (rv < 0)
845 		return rv;
846 
847 	if (!usblp->present) {
848 		count = -ENODEV;
849 		goto done;
850 	}
851 
852 	if ((avail = usblp->rstatus) < 0) {
853 		printk(KERN_ERR "usblp%d: error %d reading from printer\n",
854 		    usblp->minor, (int)avail);
855 		usblp_submit_read(usblp);
856 		count = -EIO;
857 		goto done;
858 	}
859 
860 	count = len < avail - usblp->readcount ? len : avail - usblp->readcount;
861 	if (count != 0 &&
862 	    copy_to_user(buffer, usblp->readbuf + usblp->readcount, count)) {
863 		count = -EFAULT;
864 		goto done;
865 	}
866 
867 	if ((usblp->readcount += count) == avail) {
868 		if (usblp_submit_read(usblp) < 0) {
869 			/* We don't want to leak USB return codes into errno. */
870 			if (count == 0)
871 				count = -EIO;
872 			goto done;
873 		}
874 	}
875 
876 done:
877 	mutex_unlock(&usblp->mut);
878 	return count;
879 }
880 
881 /*
882  * Wait for the write path to come idle.
883  * This is called under the ->wmut, so the idle path stays idle.
884  *
885  * Our write path has a peculiar property: it does not buffer like a tty,
886  * but waits for the write to succeed. This allows our ->release to bug out
887  * without waiting for writes to drain. But it obviously does not work
888  * when O_NONBLOCK is set. So, applications setting O_NONBLOCK must use
889  * select(2) or poll(2) to wait for the buffer to drain before closing.
890  * Alternatively, set blocking mode with fcntl and issue a zero-size write.
891  */
892 static int usblp_wwait(struct usblp *usblp, int nonblock)
893 {
894 	DECLARE_WAITQUEUE(waita, current);
895 	int rc;
896 	int err = 0;
897 
898 	add_wait_queue(&usblp->wwait, &waita);
899 	for (;;) {
900 		if (mutex_lock_interruptible(&usblp->mut)) {
901 			rc = -EINTR;
902 			break;
903 		}
904 		set_current_state(TASK_INTERRUPTIBLE);
905 		rc = usblp_wtest(usblp, nonblock);
906 		mutex_unlock(&usblp->mut);
907 		if (rc <= 0)
908 			break;
909 
910 		if (schedule_timeout(msecs_to_jiffies(1500)) == 0) {
911 			if (usblp->flags & LP_ABORT) {
912 				err = usblp_check_status(usblp, err);
913 				if (err == 1) {	/* Paper out */
914 					rc = -ENOSPC;
915 					break;
916 				}
917 			} else {
918 				/* Prod the printer, Gentoo#251237. */
919 				mutex_lock(&usblp->mut);
920 				usblp_read_status(usblp, usblp->statusbuf);
921 				mutex_unlock(&usblp->mut);
922 			}
923 		}
924 	}
925 	set_current_state(TASK_RUNNING);
926 	remove_wait_queue(&usblp->wwait, &waita);
927 	return rc;
928 }
929 
930 static int usblp_wtest(struct usblp *usblp, int nonblock)
931 {
932 	unsigned long flags;
933 
934 	if (!usblp->present)
935 		return -ENODEV;
936 	if (signal_pending(current))
937 		return -EINTR;
938 	spin_lock_irqsave(&usblp->lock, flags);
939 	if (usblp->wcomplete) {
940 		spin_unlock_irqrestore(&usblp->lock, flags);
941 		return 0;
942 	}
943 	spin_unlock_irqrestore(&usblp->lock, flags);
944 	if (nonblock)
945 		return -EAGAIN;
946 	return 1;
947 }
948 
949 /*
950  * Wait for read bytes to become available. This probably should have been
951  * called usblp_r_lock_and_wait(), because we lock first. But it's a traditional
952  * name for functions which lock and return.
953  *
954  * We do not use wait_event_interruptible because it makes locking iffy.
955  */
956 static int usblp_rwait_and_lock(struct usblp *usblp, int nonblock)
957 {
958 	DECLARE_WAITQUEUE(waita, current);
959 	int rc;
960 
961 	add_wait_queue(&usblp->rwait, &waita);
962 	for (;;) {
963 		if (mutex_lock_interruptible(&usblp->mut)) {
964 			rc = -EINTR;
965 			break;
966 		}
967 		set_current_state(TASK_INTERRUPTIBLE);
968 		if ((rc = usblp_rtest(usblp, nonblock)) < 0) {
969 			mutex_unlock(&usblp->mut);
970 			break;
971 		}
972 		if (rc == 0)	/* Keep it locked */
973 			break;
974 		mutex_unlock(&usblp->mut);
975 		schedule();
976 	}
977 	set_current_state(TASK_RUNNING);
978 	remove_wait_queue(&usblp->rwait, &waita);
979 	return rc;
980 }
981 
982 static int usblp_rtest(struct usblp *usblp, int nonblock)
983 {
984 	unsigned long flags;
985 
986 	if (!usblp->present)
987 		return -ENODEV;
988 	if (signal_pending(current))
989 		return -EINTR;
990 	spin_lock_irqsave(&usblp->lock, flags);
991 	if (usblp->rcomplete) {
992 		spin_unlock_irqrestore(&usblp->lock, flags);
993 		return 0;
994 	}
995 	spin_unlock_irqrestore(&usblp->lock, flags);
996 	if (nonblock)
997 		return -EAGAIN;
998 	return 1;
999 }
1000 
1001 /*
1002  * Please check ->bidir and other such things outside for now.
1003  */
1004 static int usblp_submit_read(struct usblp *usblp)
1005 {
1006 	struct urb *urb;
1007 	unsigned long flags;
1008 	int rc;
1009 
1010 	rc = -ENOMEM;
1011 	urb = usb_alloc_urb(0, GFP_KERNEL);
1012 	if (urb == NULL)
1013 		goto raise_urb;
1014 
1015 	usb_fill_bulk_urb(urb, usblp->dev,
1016 		usb_rcvbulkpipe(usblp->dev,
1017 		  usblp->protocol[usblp->current_protocol].epread->bEndpointAddress),
1018 		usblp->readbuf, USBLP_BUF_SIZE_IN,
1019 		usblp_bulk_read, usblp);
1020 	usb_anchor_urb(urb, &usblp->urbs);
1021 
1022 	spin_lock_irqsave(&usblp->lock, flags);
1023 	usblp->readcount = 0; /* XXX Why here? */
1024 	usblp->rcomplete = 0;
1025 	spin_unlock_irqrestore(&usblp->lock, flags);
1026 	if ((rc = usb_submit_urb(urb, GFP_KERNEL)) < 0) {
1027 		dev_dbg(&usblp->intf->dev, "error submitting urb (%d)\n", rc);
1028 		spin_lock_irqsave(&usblp->lock, flags);
1029 		usblp->rstatus = rc;
1030 		usblp->rcomplete = 1;
1031 		spin_unlock_irqrestore(&usblp->lock, flags);
1032 		goto raise_submit;
1033 	}
1034 
1035 	return 0;
1036 
1037 raise_submit:
1038 	usb_unanchor_urb(urb);
1039 	usb_free_urb(urb);
1040 raise_urb:
1041 	return rc;
1042 }
1043 
1044 /*
1045  * Checks for printers that have quirks, such as requiring unidirectional
1046  * communication but reporting bidirectional; currently some HP printers
1047  * have this flaw (HP 810, 880, 895, etc.), or needing an init string
1048  * sent at each open (like some Epsons).
1049  * Returns 1 if found, 0 if not found.
1050  *
1051  * HP recommended that we use the bidirectional interface but
1052  * don't attempt any bulk IN transfers from the IN endpoint.
1053  * Here's some more detail on the problem:
1054  * The problem is not that it isn't bidirectional though. The problem
1055  * is that if you request a device ID, or status information, while
1056  * the buffers are full, the return data will end up in the print data
1057  * buffer. For example if you make sure you never request the device ID
1058  * while you are sending print data, and you don't try to query the
1059  * printer status every couple of milliseconds, you will probably be OK.
1060  */
1061 static unsigned int usblp_quirks(__u16 vendor, __u16 product)
1062 {
1063 	int i;
1064 
1065 	for (i = 0; quirk_printers[i].vendorId; i++) {
1066 		if (vendor == quirk_printers[i].vendorId &&
1067 		    product == quirk_printers[i].productId)
1068 			return quirk_printers[i].quirks;
1069 	}
1070 	return 0;
1071 }
1072 
1073 static const struct file_operations usblp_fops = {
1074 	.owner =	THIS_MODULE,
1075 	.read =		usblp_read,
1076 	.write =	usblp_write,
1077 	.poll =		usblp_poll,
1078 	.unlocked_ioctl =	usblp_ioctl,
1079 	.compat_ioctl =		usblp_ioctl,
1080 	.open =		usblp_open,
1081 	.release =	usblp_release,
1082 	.llseek =	noop_llseek,
1083 };
1084 
1085 static char *usblp_devnode(struct device *dev, umode_t *mode)
1086 {
1087 	return kasprintf(GFP_KERNEL, "usb/%s", dev_name(dev));
1088 }
1089 
1090 static struct usb_class_driver usblp_class = {
1091 	.name =		"lp%d",
1092 	.devnode =	usblp_devnode,
1093 	.fops =		&usblp_fops,
1094 	.minor_base =	USBLP_MINOR_BASE,
1095 };
1096 
1097 static ssize_t ieee1284_id_show(struct device *dev, struct device_attribute *attr, char *buf)
1098 {
1099 	struct usb_interface *intf = to_usb_interface(dev);
1100 	struct usblp *usblp = usb_get_intfdata(intf);
1101 
1102 	if (usblp->device_id_string[0] == 0 &&
1103 	    usblp->device_id_string[1] == 0)
1104 		return 0;
1105 
1106 	return sprintf(buf, "%s", usblp->device_id_string+2);
1107 }
1108 
1109 static DEVICE_ATTR_RO(ieee1284_id);
1110 
1111 static struct attribute *usblp_attrs[] = {
1112 	&dev_attr_ieee1284_id.attr,
1113 	NULL,
1114 };
1115 ATTRIBUTE_GROUPS(usblp);
1116 
1117 static int usblp_probe(struct usb_interface *intf,
1118 		       const struct usb_device_id *id)
1119 {
1120 	struct usb_device *dev = interface_to_usbdev(intf);
1121 	struct usblp *usblp;
1122 	int protocol;
1123 	int retval;
1124 
1125 	/* Malloc and start initializing usblp structure so we can use it
1126 	 * directly. */
1127 	usblp = kzalloc(sizeof(struct usblp), GFP_KERNEL);
1128 	if (!usblp) {
1129 		retval = -ENOMEM;
1130 		goto abort_ret;
1131 	}
1132 	usblp->dev = dev;
1133 	mutex_init(&usblp->wmut);
1134 	mutex_init(&usblp->mut);
1135 	spin_lock_init(&usblp->lock);
1136 	init_waitqueue_head(&usblp->rwait);
1137 	init_waitqueue_head(&usblp->wwait);
1138 	init_usb_anchor(&usblp->urbs);
1139 	usblp->ifnum = intf->cur_altsetting->desc.bInterfaceNumber;
1140 	usblp->intf = usb_get_intf(intf);
1141 
1142 	/* Malloc device ID string buffer to the largest expected length,
1143 	 * since we can re-query it on an ioctl and a dynamic string
1144 	 * could change in length. */
1145 	if (!(usblp->device_id_string = kmalloc(USBLP_DEVICE_ID_SIZE, GFP_KERNEL))) {
1146 		retval = -ENOMEM;
1147 		goto abort;
1148 	}
1149 
1150 	/*
1151 	 * Allocate read buffer. We somewhat wastefully
1152 	 * malloc both regardless of bidirectionality, because the
1153 	 * alternate setting can be changed later via an ioctl.
1154 	 */
1155 	if (!(usblp->readbuf = kmalloc(USBLP_BUF_SIZE_IN, GFP_KERNEL))) {
1156 		retval = -ENOMEM;
1157 		goto abort;
1158 	}
1159 
1160 	/* Allocate buffer for printer status */
1161 	usblp->statusbuf = kmalloc(STATUS_BUF_SIZE, GFP_KERNEL);
1162 	if (!usblp->statusbuf) {
1163 		retval = -ENOMEM;
1164 		goto abort;
1165 	}
1166 
1167 	/* Lookup quirks for this printer. */
1168 	usblp->quirks = usblp_quirks(
1169 		le16_to_cpu(dev->descriptor.idVendor),
1170 		le16_to_cpu(dev->descriptor.idProduct));
1171 
1172 	/* Analyze and pick initial alternate settings and endpoints. */
1173 	protocol = usblp_select_alts(usblp);
1174 	if (protocol < 0) {
1175 		dev_dbg(&intf->dev,
1176 			"incompatible printer-class device 0x%4.4X/0x%4.4X\n",
1177 			le16_to_cpu(dev->descriptor.idVendor),
1178 			le16_to_cpu(dev->descriptor.idProduct));
1179 		retval = -ENODEV;
1180 		goto abort;
1181 	}
1182 
1183 	/* Setup the selected alternate setting and endpoints. */
1184 	if (usblp_set_protocol(usblp, protocol) < 0) {
1185 		retval = -ENODEV;	/* ->probe isn't ->ioctl */
1186 		goto abort;
1187 	}
1188 
1189 	/* Retrieve and store the device ID string. */
1190 	usblp_cache_device_id_string(usblp);
1191 
1192 #ifdef DEBUG
1193 	usblp_check_status(usblp, 0);
1194 #endif
1195 
1196 	usb_set_intfdata(intf, usblp);
1197 
1198 	usblp->present = 1;
1199 
1200 	retval = usb_register_dev(intf, &usblp_class);
1201 	if (retval) {
1202 		dev_err(&intf->dev,
1203 			"usblp: Not able to get a minor (base %u, slice default): %d\n",
1204 			USBLP_MINOR_BASE, retval);
1205 		goto abort_intfdata;
1206 	}
1207 	usblp->minor = intf->minor;
1208 	dev_info(&intf->dev,
1209 		"usblp%d: USB %sdirectional printer dev %d if %d alt %d proto %d vid 0x%4.4X pid 0x%4.4X\n",
1210 		usblp->minor, usblp->bidir ? "Bi" : "Uni", dev->devnum,
1211 		usblp->ifnum,
1212 		usblp->protocol[usblp->current_protocol].alt_setting,
1213 		usblp->current_protocol,
1214 		le16_to_cpu(usblp->dev->descriptor.idVendor),
1215 		le16_to_cpu(usblp->dev->descriptor.idProduct));
1216 
1217 	return 0;
1218 
1219 abort_intfdata:
1220 	usb_set_intfdata(intf, NULL);
1221 abort:
1222 	kfree(usblp->readbuf);
1223 	kfree(usblp->statusbuf);
1224 	kfree(usblp->device_id_string);
1225 	usb_put_intf(usblp->intf);
1226 	kfree(usblp);
1227 abort_ret:
1228 	return retval;
1229 }
1230 
1231 /*
1232  * We are a "new" style driver with usb_device_id table,
1233  * but our requirements are too intricate for simple match to handle.
1234  *
1235  * The "proto_bias" option may be used to specify the preferred protocol
1236  * for all USB printers (1=USB_CLASS_PRINTER/1/1, 2=USB_CLASS_PRINTER/1/2,
1237  * 3=USB_CLASS_PRINTER/1/3).  If the device supports the preferred protocol,
1238  * then we bind to it.
1239  *
1240  * The best interface for us is USB_CLASS_PRINTER/1/2, because it
1241  * is compatible with a stream of characters. If we find it, we bind to it.
1242  *
1243  * Note that the people from hpoj.sourceforge.net need to be able to
1244  * bind to USB_CLASS_PRINTER/1/3 (MLC/1284.4), so we provide them ioctls
1245  * for this purpose.
1246  *
1247  * Failing USB_CLASS_PRINTER/1/2, we look for USB_CLASS_PRINTER/1/3,
1248  * even though it's probably not stream-compatible, because this matches
1249  * the behaviour of the old code.
1250  *
1251  * If nothing else, we bind to USB_CLASS_PRINTER/1/1
1252  * - the unidirectional interface.
1253  */
1254 static int usblp_select_alts(struct usblp *usblp)
1255 {
1256 	struct usb_interface *if_alt;
1257 	struct usb_host_interface *ifd;
1258 	struct usb_endpoint_descriptor *epwrite, *epread;
1259 	int p, i;
1260 	int res;
1261 
1262 	if_alt = usblp->intf;
1263 
1264 	for (p = 0; p < USBLP_MAX_PROTOCOLS; p++)
1265 		usblp->protocol[p].alt_setting = -1;
1266 
1267 	/* Find out what we have. */
1268 	for (i = 0; i < if_alt->num_altsetting; i++) {
1269 		ifd = &if_alt->altsetting[i];
1270 
1271 		if (ifd->desc.bInterfaceClass != USB_CLASS_PRINTER ||
1272 		    ifd->desc.bInterfaceSubClass != 1)
1273 			if (!(usblp->quirks & USBLP_QUIRK_BAD_CLASS))
1274 				continue;
1275 
1276 		if (ifd->desc.bInterfaceProtocol < USBLP_FIRST_PROTOCOL ||
1277 		    ifd->desc.bInterfaceProtocol > USBLP_LAST_PROTOCOL)
1278 			continue;
1279 
1280 		/* Look for the expected bulk endpoints. */
1281 		if (ifd->desc.bInterfaceProtocol > 1) {
1282 			res = usb_find_common_endpoints(ifd,
1283 					&epread, &epwrite, NULL, NULL);
1284 		} else {
1285 			epread = NULL;
1286 			res = usb_find_bulk_out_endpoint(ifd, &epwrite);
1287 		}
1288 
1289 		/* Ignore buggy hardware without the right endpoints. */
1290 		if (res)
1291 			continue;
1292 
1293 		/* Turn off reads for buggy bidirectional printers. */
1294 		if (usblp->quirks & USBLP_QUIRK_BIDIR) {
1295 			printk(KERN_INFO "usblp%d: Disabling reads from "
1296 			    "problematic bidirectional printer\n",
1297 			    usblp->minor);
1298 			epread = NULL;
1299 		}
1300 
1301 		usblp->protocol[ifd->desc.bInterfaceProtocol].alt_setting =
1302 				ifd->desc.bAlternateSetting;
1303 		usblp->protocol[ifd->desc.bInterfaceProtocol].epwrite = epwrite;
1304 		usblp->protocol[ifd->desc.bInterfaceProtocol].epread = epread;
1305 	}
1306 
1307 	/* If our requested protocol is supported, then use it. */
1308 	if (proto_bias >= USBLP_FIRST_PROTOCOL &&
1309 	    proto_bias <= USBLP_LAST_PROTOCOL &&
1310 	    usblp->protocol[proto_bias].alt_setting != -1)
1311 		return proto_bias;
1312 
1313 	/* Ordering is important here. */
1314 	if (usblp->protocol[2].alt_setting != -1)
1315 		return 2;
1316 	if (usblp->protocol[1].alt_setting != -1)
1317 		return 1;
1318 	if (usblp->protocol[3].alt_setting != -1)
1319 		return 3;
1320 
1321 	/* If nothing is available, then don't bind to this device. */
1322 	return -1;
1323 }
1324 
1325 static int usblp_set_protocol(struct usblp *usblp, int protocol)
1326 {
1327 	int r, alts;
1328 
1329 	if (protocol < USBLP_FIRST_PROTOCOL || protocol > USBLP_LAST_PROTOCOL)
1330 		return -EINVAL;
1331 
1332 	alts = usblp->protocol[protocol].alt_setting;
1333 	if (alts < 0)
1334 		return -EINVAL;
1335 	r = usb_set_interface(usblp->dev, usblp->ifnum, alts);
1336 	if (r < 0) {
1337 		printk(KERN_ERR "usblp: can't set desired altsetting %d on interface %d\n",
1338 			alts, usblp->ifnum);
1339 		return r;
1340 	}
1341 
1342 	usblp->bidir = (usblp->protocol[protocol].epread != NULL);
1343 	usblp->current_protocol = protocol;
1344 	dev_dbg(&usblp->intf->dev, "usblp%d set protocol %d\n",
1345 		usblp->minor, protocol);
1346 	return 0;
1347 }
1348 
1349 /* Retrieves and caches device ID string.
1350  * Returns length, including length bytes but not null terminator.
1351  * On error, returns a negative errno value. */
1352 static int usblp_cache_device_id_string(struct usblp *usblp)
1353 {
1354 	int err, length;
1355 
1356 	err = usblp_get_id(usblp, 0, usblp->device_id_string, USBLP_DEVICE_ID_SIZE - 1);
1357 	if (err < 0) {
1358 		dev_dbg(&usblp->intf->dev,
1359 			"usblp%d: error = %d reading IEEE-1284 Device ID string\n",
1360 			usblp->minor, err);
1361 		usblp->device_id_string[0] = usblp->device_id_string[1] = '\0';
1362 		return -EIO;
1363 	}
1364 
1365 	/* First two bytes are length in big-endian.
1366 	 * They count themselves, and we copy them into
1367 	 * the user's buffer. */
1368 	length = be16_to_cpu(*((__be16 *)usblp->device_id_string));
1369 	if (length < 2)
1370 		length = 2;
1371 	else if (length >= USBLP_DEVICE_ID_SIZE)
1372 		length = USBLP_DEVICE_ID_SIZE - 1;
1373 	usblp->device_id_string[length] = '\0';
1374 
1375 	dev_dbg(&usblp->intf->dev, "usblp%d Device ID string [len=%d]=\"%s\"\n",
1376 		usblp->minor, length, &usblp->device_id_string[2]);
1377 
1378 	return length;
1379 }
1380 
1381 static void usblp_disconnect(struct usb_interface *intf)
1382 {
1383 	struct usblp *usblp = usb_get_intfdata(intf);
1384 
1385 	usb_deregister_dev(intf, &usblp_class);
1386 
1387 	if (!usblp || !usblp->dev) {
1388 		dev_err(&intf->dev, "bogus disconnect\n");
1389 		BUG();
1390 	}
1391 
1392 	mutex_lock(&usblp_mutex);
1393 	mutex_lock(&usblp->mut);
1394 	usblp->present = 0;
1395 	wake_up(&usblp->wwait);
1396 	wake_up(&usblp->rwait);
1397 	usb_set_intfdata(intf, NULL);
1398 
1399 	usblp_unlink_urbs(usblp);
1400 	mutex_unlock(&usblp->mut);
1401 	usb_poison_anchored_urbs(&usblp->urbs);
1402 
1403 	if (!usblp->used)
1404 		usblp_cleanup(usblp);
1405 
1406 	mutex_unlock(&usblp_mutex);
1407 }
1408 
1409 static int usblp_suspend(struct usb_interface *intf, pm_message_t message)
1410 {
1411 	struct usblp *usblp = usb_get_intfdata(intf);
1412 
1413 	usblp_unlink_urbs(usblp);
1414 #if 0 /* XXX Do we want this? What if someone is reading, should we fail? */
1415 	/* not strictly necessary, but just in case */
1416 	wake_up(&usblp->wwait);
1417 	wake_up(&usblp->rwait);
1418 #endif
1419 
1420 	return 0;
1421 }
1422 
1423 static int usblp_resume(struct usb_interface *intf)
1424 {
1425 	struct usblp *usblp = usb_get_intfdata(intf);
1426 	int r;
1427 
1428 	r = handle_bidir(usblp);
1429 
1430 	return r;
1431 }
1432 
1433 static const struct usb_device_id usblp_ids[] = {
1434 	{ USB_DEVICE_INFO(USB_CLASS_PRINTER, 1, 1) },
1435 	{ USB_DEVICE_INFO(USB_CLASS_PRINTER, 1, 2) },
1436 	{ USB_DEVICE_INFO(USB_CLASS_PRINTER, 1, 3) },
1437 	{ USB_INTERFACE_INFO(USB_CLASS_PRINTER, 1, 1) },
1438 	{ USB_INTERFACE_INFO(USB_CLASS_PRINTER, 1, 2) },
1439 	{ USB_INTERFACE_INFO(USB_CLASS_PRINTER, 1, 3) },
1440 	{ USB_DEVICE(0x04b8, 0x0202) },	/* Seiko Epson Receipt Printer M129C */
1441 	{ }						/* Terminating entry */
1442 };
1443 
1444 MODULE_DEVICE_TABLE(usb, usblp_ids);
1445 
1446 static struct usb_driver usblp_driver = {
1447 	.name =		"usblp",
1448 	.probe =	usblp_probe,
1449 	.disconnect =	usblp_disconnect,
1450 	.suspend =	usblp_suspend,
1451 	.resume =	usblp_resume,
1452 	.id_table =	usblp_ids,
1453 	.dev_groups =	usblp_groups,
1454 	.supports_autosuspend =	1,
1455 };
1456 
1457 module_usb_driver(usblp_driver);
1458 
1459 MODULE_AUTHOR(DRIVER_AUTHOR);
1460 MODULE_DESCRIPTION(DRIVER_DESC);
1461 module_param(proto_bias, int, S_IRUGO | S_IWUSR);
1462 MODULE_PARM_DESC(proto_bias, "Favourite protocol number");
1463 MODULE_LICENSE("GPL");
1464