xref: /openbmc/linux/drivers/usb/class/usblp.c (revision 82b5d164)
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 #define usblp_hp_channel_change_request(usblp, channel, buffer) \
278 	usblp_ctrl_msg(usblp, USBLP_REQ_HP_CHANNEL_CHANGE_REQUEST, USB_TYPE_VENDOR, USB_DIR_IN, USB_RECIP_INTERFACE, channel, buffer, 1)
279 
280 /*
281  * See the description for usblp_select_alts() below for the usage
282  * explanation.  Look into your /sys/kernel/debug/usb/devices and dmesg in
283  * case of any trouble.
284  */
285 static int proto_bias = -1;
286 
287 /*
288  * URB callback.
289  */
290 
291 static void usblp_bulk_read(struct urb *urb)
292 {
293 	struct usblp *usblp = urb->context;
294 	int status = urb->status;
295 	unsigned long flags;
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_irqsave(&usblp->lock, flags);
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_irqrestore(&usblp->lock, flags);
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 	unsigned long flags;
320 
321 	if (usblp->present && usblp->used) {
322 		if (status)
323 			printk(KERN_WARNING "usblp%d: "
324 			    "nonzero write bulk status received: %d\n",
325 			    usblp->minor, status);
326 	}
327 	spin_lock_irqsave(&usblp->lock, flags);
328 	if (status < 0)
329 		usblp->wstatus = status;
330 	else
331 		usblp->wstatus = urb->actual_length;
332 	usblp->no_paper = 0;
333 	usblp->wcomplete = 1;
334 	wake_up(&usblp->wwait);
335 	spin_unlock_irqrestore(&usblp->lock, flags);
336 
337 	usb_free_urb(urb);
338 }
339 
340 /*
341  * Get and print printer errors.
342  */
343 
344 static const char *usblp_messages[] = { "ok", "out of paper", "off-line", "on fire" };
345 
346 static int usblp_check_status(struct usblp *usblp, int err)
347 {
348 	unsigned char status, newerr = 0;
349 	int error;
350 
351 	mutex_lock(&usblp->mut);
352 	if ((error = usblp_read_status(usblp, usblp->statusbuf)) < 0) {
353 		mutex_unlock(&usblp->mut);
354 		printk_ratelimited(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) {
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 	usblp = usb_get_intfdata(intf);
407 	if (!usblp || !usblp->dev || !usblp->present)
408 		goto out;
409 
410 	retval = -EBUSY;
411 	if (usblp->used)
412 		goto out;
413 
414 	/*
415 	 * We do not implement LP_ABORTOPEN/LPABORTOPEN for two reasons:
416 	 *  - We do not want persistent state which close(2) does not clear
417 	 *  - It is not used anyway, according to CUPS people
418 	 */
419 
420 	retval = usb_autopm_get_interface(intf);
421 	if (retval < 0)
422 		goto out;
423 	usblp->used = 1;
424 	file->private_data = usblp;
425 
426 	usblp->wcomplete = 1; /* we begin writeable */
427 	usblp->wstatus = 0;
428 	usblp->rcomplete = 0;
429 
430 	if (handle_bidir(usblp) < 0) {
431 		usb_autopm_put_interface(intf);
432 		usblp->used = 0;
433 		file->private_data = NULL;
434 		retval = -EIO;
435 	}
436 out:
437 	mutex_unlock(&usblp_mutex);
438 	return retval;
439 }
440 
441 static void usblp_cleanup(struct usblp *usblp)
442 {
443 	printk(KERN_INFO "usblp%d: removed\n", usblp->minor);
444 
445 	kfree(usblp->readbuf);
446 	kfree(usblp->device_id_string);
447 	kfree(usblp->statusbuf);
448 	kfree(usblp);
449 }
450 
451 static void usblp_unlink_urbs(struct usblp *usblp)
452 {
453 	usb_kill_anchored_urbs(&usblp->urbs);
454 }
455 
456 static int usblp_release(struct inode *inode, struct file *file)
457 {
458 	struct usblp *usblp = file->private_data;
459 
460 	usblp->flags &= ~LP_ABORT;
461 
462 	mutex_lock(&usblp_mutex);
463 	usblp->used = 0;
464 	if (usblp->present) {
465 		usblp_unlink_urbs(usblp);
466 		usb_autopm_put_interface(usblp->intf);
467 	} else		/* finish cleanup from disconnect */
468 		usblp_cleanup(usblp);
469 	mutex_unlock(&usblp_mutex);
470 	return 0;
471 }
472 
473 /* No kernel lock - fine */
474 static __poll_t usblp_poll(struct file *file, struct poll_table_struct *wait)
475 {
476 	__poll_t ret;
477 	unsigned long flags;
478 
479 	struct usblp *usblp = file->private_data;
480 	/* Should we check file->f_mode & FMODE_WRITE before poll_wait()? */
481 	poll_wait(file, &usblp->rwait, wait);
482 	poll_wait(file, &usblp->wwait, wait);
483 	spin_lock_irqsave(&usblp->lock, flags);
484 	ret = ((usblp->bidir && usblp->rcomplete) ? EPOLLIN  | EPOLLRDNORM : 0) |
485 	   ((usblp->no_paper || usblp->wcomplete) ? EPOLLOUT | EPOLLWRNORM : 0);
486 	spin_unlock_irqrestore(&usblp->lock, flags);
487 	return ret;
488 }
489 
490 static long usblp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
491 {
492 	struct usblp *usblp = file->private_data;
493 	int length, err, i;
494 	unsigned char newChannel;
495 	int status;
496 	int twoints[2];
497 	int retval = 0;
498 
499 	mutex_lock(&usblp->mut);
500 	if (!usblp->present) {
501 		retval = -ENODEV;
502 		goto done;
503 	}
504 
505 	dev_dbg(&usblp->intf->dev,
506 		"usblp_ioctl: cmd=0x%x (%c nr=%d len=%d dir=%d)\n", cmd,
507 		_IOC_TYPE(cmd), _IOC_NR(cmd), _IOC_SIZE(cmd), _IOC_DIR(cmd));
508 
509 	if (_IOC_TYPE(cmd) == 'P')	/* new-style ioctl number */
510 
511 		switch (_IOC_NR(cmd)) {
512 
513 		case IOCNR_GET_DEVICE_ID: /* get the DEVICE_ID string */
514 			if (_IOC_DIR(cmd) != _IOC_READ) {
515 				retval = -EINVAL;
516 				goto done;
517 			}
518 
519 			length = usblp_cache_device_id_string(usblp);
520 			if (length < 0) {
521 				retval = length;
522 				goto done;
523 			}
524 			if (length > _IOC_SIZE(cmd))
525 				length = _IOC_SIZE(cmd); /* truncate */
526 
527 			if (copy_to_user((void __user *) arg,
528 					usblp->device_id_string,
529 					(unsigned long) length)) {
530 				retval = -EFAULT;
531 				goto done;
532 			}
533 
534 			break;
535 
536 		case IOCNR_GET_PROTOCOLS:
537 			if (_IOC_DIR(cmd) != _IOC_READ ||
538 			    _IOC_SIZE(cmd) < sizeof(twoints)) {
539 				retval = -EINVAL;
540 				goto done;
541 			}
542 
543 			twoints[0] = usblp->current_protocol;
544 			twoints[1] = 0;
545 			for (i = USBLP_FIRST_PROTOCOL;
546 			     i <= USBLP_LAST_PROTOCOL; i++) {
547 				if (usblp->protocol[i].alt_setting >= 0)
548 					twoints[1] |= (1<<i);
549 			}
550 
551 			if (copy_to_user((void __user *)arg,
552 					(unsigned char *)twoints,
553 					sizeof(twoints))) {
554 				retval = -EFAULT;
555 				goto done;
556 			}
557 
558 			break;
559 
560 		case IOCNR_SET_PROTOCOL:
561 			if (_IOC_DIR(cmd) != _IOC_WRITE) {
562 				retval = -EINVAL;
563 				goto done;
564 			}
565 
566 #ifdef DEBUG
567 			if (arg == -10) {
568 				usblp_dump(usblp);
569 				break;
570 			}
571 #endif
572 
573 			usblp_unlink_urbs(usblp);
574 			retval = usblp_set_protocol(usblp, arg);
575 			if (retval < 0) {
576 				usblp_set_protocol(usblp,
577 					usblp->current_protocol);
578 			}
579 			break;
580 
581 		case IOCNR_HP_SET_CHANNEL:
582 			if (_IOC_DIR(cmd) != _IOC_WRITE ||
583 			    le16_to_cpu(usblp->dev->descriptor.idVendor) != 0x03F0 ||
584 			    usblp->quirks & USBLP_QUIRK_BIDIR) {
585 				retval = -EINVAL;
586 				goto done;
587 			}
588 
589 			err = usblp_hp_channel_change_request(usblp,
590 				arg, &newChannel);
591 			if (err < 0) {
592 				dev_err(&usblp->dev->dev,
593 					"usblp%d: error = %d setting "
594 					"HP channel\n",
595 					usblp->minor, err);
596 				retval = -EIO;
597 				goto done;
598 			}
599 
600 			dev_dbg(&usblp->intf->dev,
601 				"usblp%d requested/got HP channel %ld/%d\n",
602 				usblp->minor, arg, newChannel);
603 			break;
604 
605 		case IOCNR_GET_BUS_ADDRESS:
606 			if (_IOC_DIR(cmd) != _IOC_READ ||
607 			    _IOC_SIZE(cmd) < sizeof(twoints)) {
608 				retval = -EINVAL;
609 				goto done;
610 			}
611 
612 			twoints[0] = usblp->dev->bus->busnum;
613 			twoints[1] = usblp->dev->devnum;
614 			if (copy_to_user((void __user *)arg,
615 					(unsigned char *)twoints,
616 					sizeof(twoints))) {
617 				retval = -EFAULT;
618 				goto done;
619 			}
620 
621 			dev_dbg(&usblp->intf->dev,
622 				"usblp%d is bus=%d, device=%d\n",
623 				usblp->minor, twoints[0], twoints[1]);
624 			break;
625 
626 		case IOCNR_GET_VID_PID:
627 			if (_IOC_DIR(cmd) != _IOC_READ ||
628 			    _IOC_SIZE(cmd) < sizeof(twoints)) {
629 				retval = -EINVAL;
630 				goto done;
631 			}
632 
633 			twoints[0] = le16_to_cpu(usblp->dev->descriptor.idVendor);
634 			twoints[1] = le16_to_cpu(usblp->dev->descriptor.idProduct);
635 			if (copy_to_user((void __user *)arg,
636 					(unsigned char *)twoints,
637 					sizeof(twoints))) {
638 				retval = -EFAULT;
639 				goto done;
640 			}
641 
642 			dev_dbg(&usblp->intf->dev,
643 				"usblp%d is VID=0x%4.4X, PID=0x%4.4X\n",
644 				usblp->minor, twoints[0], twoints[1]);
645 			break;
646 
647 		case IOCNR_SOFT_RESET:
648 			if (_IOC_DIR(cmd) != _IOC_NONE) {
649 				retval = -EINVAL;
650 				goto done;
651 			}
652 			retval = usblp_reset(usblp);
653 			break;
654 		default:
655 			retval = -ENOTTY;
656 		}
657 	else	/* old-style ioctl value */
658 		switch (cmd) {
659 
660 		case LPGETSTATUS:
661 			retval = usblp_read_status(usblp, usblp->statusbuf);
662 			if (retval) {
663 				printk_ratelimited(KERN_ERR "usblp%d:"
664 					    "failed reading printer status (%d)\n",
665 					    usblp->minor, retval);
666 				retval = -EIO;
667 				goto done;
668 			}
669 			status = *usblp->statusbuf;
670 			if (copy_to_user((void __user *)arg, &status, sizeof(int)))
671 				retval = -EFAULT;
672 			break;
673 
674 		case LPABORT:
675 			if (arg)
676 				usblp->flags |= LP_ABORT;
677 			else
678 				usblp->flags &= ~LP_ABORT;
679 			break;
680 
681 		default:
682 			retval = -ENOTTY;
683 		}
684 
685 done:
686 	mutex_unlock(&usblp->mut);
687 	return retval;
688 }
689 
690 static struct urb *usblp_new_writeurb(struct usblp *usblp, int transfer_length)
691 {
692 	struct urb *urb;
693 	char *writebuf;
694 
695 	writebuf = kmalloc(transfer_length, GFP_KERNEL);
696 	if (writebuf == NULL)
697 		return NULL;
698 	urb = usb_alloc_urb(0, GFP_KERNEL);
699 	if (urb == 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 		writeurb = usblp_new_writeurb(usblp, transfer_length);
737 		if (writeurb == NULL)
738 			goto raise_urb;
739 		usb_anchor_urb(writeurb, &usblp->urbs);
740 
741 		if (copy_from_user(writeurb->transfer_buffer,
742 				   buffer + writecount, transfer_length)) {
743 			rv = -EFAULT;
744 			goto raise_badaddr;
745 		}
746 
747 		spin_lock_irq(&usblp->lock);
748 		usblp->wcomplete = 0;
749 		spin_unlock_irq(&usblp->lock);
750 		if ((rv = usb_submit_urb(writeurb, GFP_KERNEL)) < 0) {
751 			usblp->wstatus = 0;
752 			spin_lock_irq(&usblp->lock);
753 			usblp->no_paper = 0;
754 			usblp->wcomplete = 1;
755 			wake_up(&usblp->wwait);
756 			spin_unlock_irq(&usblp->lock);
757 			if (rv != -ENOMEM)
758 				rv = -EIO;
759 			goto raise_submit;
760 		}
761 
762 		/*
763 		 * Step 2: Wait for transfer to end, collect results.
764 		 */
765 		rv = usblp_wwait(usblp, !!(file->f_flags&O_NONBLOCK));
766 		if (rv < 0) {
767 			if (rv == -EAGAIN) {
768 				/* Presume that it's going to complete well. */
769 				writecount += transfer_length;
770 			}
771 			if (rv == -ENOSPC) {
772 				spin_lock_irq(&usblp->lock);
773 				usblp->no_paper = 1;	/* Mark for poll(2) */
774 				spin_unlock_irq(&usblp->lock);
775 				writecount += transfer_length;
776 			}
777 			/* Leave URB dangling, to be cleaned on close. */
778 			goto collect_error;
779 		}
780 
781 		if (usblp->wstatus < 0) {
782 			rv = -EIO;
783 			goto collect_error;
784 		}
785 		/*
786 		 * This is critical: it must be our URB, not other writer's.
787 		 * The wmut exists mainly to cover us here.
788 		 */
789 		writecount += usblp->wstatus;
790 	}
791 
792 	mutex_unlock(&usblp->wmut);
793 	return writecount;
794 
795 raise_submit:
796 raise_badaddr:
797 	usb_unanchor_urb(writeurb);
798 	usb_free_urb(writeurb);
799 raise_urb:
800 raise_wait:
801 collect_error:		/* Out of raise sequence */
802 	mutex_unlock(&usblp->wmut);
803 raise_biglock:
804 	return writecount ? writecount : rv;
805 }
806 
807 /*
808  * Notice that we fail to restart in a few cases: on EFAULT, on restart
809  * error, etc. This is the historical behaviour. In all such cases we return
810  * EIO, and applications loop in order to get the new read going.
811  */
812 static ssize_t usblp_read(struct file *file, char __user *buffer, size_t len, loff_t *ppos)
813 {
814 	struct usblp *usblp = file->private_data;
815 	ssize_t count;
816 	ssize_t avail;
817 	int rv;
818 
819 	if (!usblp->bidir)
820 		return -EINVAL;
821 
822 	rv = usblp_rwait_and_lock(usblp, !!(file->f_flags & O_NONBLOCK));
823 	if (rv < 0)
824 		return rv;
825 
826 	if ((avail = usblp->rstatus) < 0) {
827 		printk(KERN_ERR "usblp%d: error %d reading from printer\n",
828 		    usblp->minor, (int)avail);
829 		usblp_submit_read(usblp);
830 		count = -EIO;
831 		goto done;
832 	}
833 
834 	count = len < avail - usblp->readcount ? len : avail - usblp->readcount;
835 	if (count != 0 &&
836 	    copy_to_user(buffer, usblp->readbuf + usblp->readcount, count)) {
837 		count = -EFAULT;
838 		goto done;
839 	}
840 
841 	if ((usblp->readcount += count) == avail) {
842 		if (usblp_submit_read(usblp) < 0) {
843 			/* We don't want to leak USB return codes into errno. */
844 			if (count == 0)
845 				count = -EIO;
846 			goto done;
847 		}
848 	}
849 
850 done:
851 	mutex_unlock(&usblp->mut);
852 	return count;
853 }
854 
855 /*
856  * Wait for the write path to come idle.
857  * This is called under the ->wmut, so the idle path stays idle.
858  *
859  * Our write path has a peculiar property: it does not buffer like a tty,
860  * but waits for the write to succeed. This allows our ->release to bug out
861  * without waiting for writes to drain. But it obviously does not work
862  * when O_NONBLOCK is set. So, applications setting O_NONBLOCK must use
863  * select(2) or poll(2) to wait for the buffer to drain before closing.
864  * Alternatively, set blocking mode with fcntl and issue a zero-size write.
865  */
866 static int usblp_wwait(struct usblp *usblp, int nonblock)
867 {
868 	DECLARE_WAITQUEUE(waita, current);
869 	int rc;
870 	int err = 0;
871 
872 	add_wait_queue(&usblp->wwait, &waita);
873 	for (;;) {
874 		if (mutex_lock_interruptible(&usblp->mut)) {
875 			rc = -EINTR;
876 			break;
877 		}
878 		set_current_state(TASK_INTERRUPTIBLE);
879 		rc = usblp_wtest(usblp, nonblock);
880 		mutex_unlock(&usblp->mut);
881 		if (rc <= 0)
882 			break;
883 
884 		if (schedule_timeout(msecs_to_jiffies(1500)) == 0) {
885 			if (usblp->flags & LP_ABORT) {
886 				err = usblp_check_status(usblp, err);
887 				if (err == 1) {	/* Paper out */
888 					rc = -ENOSPC;
889 					break;
890 				}
891 			} else {
892 				/* Prod the printer, Gentoo#251237. */
893 				mutex_lock(&usblp->mut);
894 				usblp_read_status(usblp, usblp->statusbuf);
895 				mutex_unlock(&usblp->mut);
896 			}
897 		}
898 	}
899 	set_current_state(TASK_RUNNING);
900 	remove_wait_queue(&usblp->wwait, &waita);
901 	return rc;
902 }
903 
904 static int usblp_wtest(struct usblp *usblp, int nonblock)
905 {
906 	unsigned long flags;
907 
908 	if (!usblp->present)
909 		return -ENODEV;
910 	if (signal_pending(current))
911 		return -EINTR;
912 	spin_lock_irqsave(&usblp->lock, flags);
913 	if (usblp->wcomplete) {
914 		spin_unlock_irqrestore(&usblp->lock, flags);
915 		return 0;
916 	}
917 	spin_unlock_irqrestore(&usblp->lock, flags);
918 	if (nonblock)
919 		return -EAGAIN;
920 	return 1;
921 }
922 
923 /*
924  * Wait for read bytes to become available. This probably should have been
925  * called usblp_r_lock_and_wait(), because we lock first. But it's a traditional
926  * name for functions which lock and return.
927  *
928  * We do not use wait_event_interruptible because it makes locking iffy.
929  */
930 static int usblp_rwait_and_lock(struct usblp *usblp, int nonblock)
931 {
932 	DECLARE_WAITQUEUE(waita, current);
933 	int rc;
934 
935 	add_wait_queue(&usblp->rwait, &waita);
936 	for (;;) {
937 		if (mutex_lock_interruptible(&usblp->mut)) {
938 			rc = -EINTR;
939 			break;
940 		}
941 		set_current_state(TASK_INTERRUPTIBLE);
942 		if ((rc = usblp_rtest(usblp, nonblock)) < 0) {
943 			mutex_unlock(&usblp->mut);
944 			break;
945 		}
946 		if (rc == 0)	/* Keep it locked */
947 			break;
948 		mutex_unlock(&usblp->mut);
949 		schedule();
950 	}
951 	set_current_state(TASK_RUNNING);
952 	remove_wait_queue(&usblp->rwait, &waita);
953 	return rc;
954 }
955 
956 static int usblp_rtest(struct usblp *usblp, int nonblock)
957 {
958 	unsigned long flags;
959 
960 	if (!usblp->present)
961 		return -ENODEV;
962 	if (signal_pending(current))
963 		return -EINTR;
964 	spin_lock_irqsave(&usblp->lock, flags);
965 	if (usblp->rcomplete) {
966 		spin_unlock_irqrestore(&usblp->lock, flags);
967 		return 0;
968 	}
969 	spin_unlock_irqrestore(&usblp->lock, flags);
970 	if (nonblock)
971 		return -EAGAIN;
972 	return 1;
973 }
974 
975 /*
976  * Please check ->bidir and other such things outside for now.
977  */
978 static int usblp_submit_read(struct usblp *usblp)
979 {
980 	struct urb *urb;
981 	unsigned long flags;
982 	int rc;
983 
984 	rc = -ENOMEM;
985 	urb = usb_alloc_urb(0, GFP_KERNEL);
986 	if (urb == NULL)
987 		goto raise_urb;
988 
989 	usb_fill_bulk_urb(urb, usblp->dev,
990 		usb_rcvbulkpipe(usblp->dev,
991 		  usblp->protocol[usblp->current_protocol].epread->bEndpointAddress),
992 		usblp->readbuf, USBLP_BUF_SIZE_IN,
993 		usblp_bulk_read, usblp);
994 	usb_anchor_urb(urb, &usblp->urbs);
995 
996 	spin_lock_irqsave(&usblp->lock, flags);
997 	usblp->readcount = 0; /* XXX Why here? */
998 	usblp->rcomplete = 0;
999 	spin_unlock_irqrestore(&usblp->lock, flags);
1000 	if ((rc = usb_submit_urb(urb, GFP_KERNEL)) < 0) {
1001 		dev_dbg(&usblp->intf->dev, "error submitting urb (%d)\n", rc);
1002 		spin_lock_irqsave(&usblp->lock, flags);
1003 		usblp->rstatus = rc;
1004 		usblp->rcomplete = 1;
1005 		spin_unlock_irqrestore(&usblp->lock, flags);
1006 		goto raise_submit;
1007 	}
1008 
1009 	return 0;
1010 
1011 raise_submit:
1012 	usb_unanchor_urb(urb);
1013 	usb_free_urb(urb);
1014 raise_urb:
1015 	return rc;
1016 }
1017 
1018 /*
1019  * Checks for printers that have quirks, such as requiring unidirectional
1020  * communication but reporting bidirectional; currently some HP printers
1021  * have this flaw (HP 810, 880, 895, etc.), or needing an init string
1022  * sent at each open (like some Epsons).
1023  * Returns 1 if found, 0 if not found.
1024  *
1025  * HP recommended that we use the bidirectional interface but
1026  * don't attempt any bulk IN transfers from the IN endpoint.
1027  * Here's some more detail on the problem:
1028  * The problem is not that it isn't bidirectional though. The problem
1029  * is that if you request a device ID, or status information, while
1030  * the buffers are full, the return data will end up in the print data
1031  * buffer. For example if you make sure you never request the device ID
1032  * while you are sending print data, and you don't try to query the
1033  * printer status every couple of milliseconds, you will probably be OK.
1034  */
1035 static unsigned int usblp_quirks(__u16 vendor, __u16 product)
1036 {
1037 	int i;
1038 
1039 	for (i = 0; quirk_printers[i].vendorId; i++) {
1040 		if (vendor == quirk_printers[i].vendorId &&
1041 		    product == quirk_printers[i].productId)
1042 			return quirk_printers[i].quirks;
1043 	}
1044 	return 0;
1045 }
1046 
1047 static const struct file_operations usblp_fops = {
1048 	.owner =	THIS_MODULE,
1049 	.read =		usblp_read,
1050 	.write =	usblp_write,
1051 	.poll =		usblp_poll,
1052 	.unlocked_ioctl =	usblp_ioctl,
1053 	.compat_ioctl =		usblp_ioctl,
1054 	.open =		usblp_open,
1055 	.release =	usblp_release,
1056 	.llseek =	noop_llseek,
1057 };
1058 
1059 static char *usblp_devnode(struct device *dev, umode_t *mode)
1060 {
1061 	return kasprintf(GFP_KERNEL, "usb/%s", dev_name(dev));
1062 }
1063 
1064 static struct usb_class_driver usblp_class = {
1065 	.name =		"lp%d",
1066 	.devnode =	usblp_devnode,
1067 	.fops =		&usblp_fops,
1068 	.minor_base =	USBLP_MINOR_BASE,
1069 };
1070 
1071 static ssize_t ieee1284_id_show(struct device *dev, struct device_attribute *attr, char *buf)
1072 {
1073 	struct usb_interface *intf = to_usb_interface(dev);
1074 	struct usblp *usblp = usb_get_intfdata(intf);
1075 
1076 	if (usblp->device_id_string[0] == 0 &&
1077 	    usblp->device_id_string[1] == 0)
1078 		return 0;
1079 
1080 	return sprintf(buf, "%s", usblp->device_id_string+2);
1081 }
1082 
1083 static DEVICE_ATTR_RO(ieee1284_id);
1084 
1085 static struct attribute *usblp_attrs[] = {
1086 	&dev_attr_ieee1284_id.attr,
1087 	NULL,
1088 };
1089 ATTRIBUTE_GROUPS(usblp);
1090 
1091 static int usblp_probe(struct usb_interface *intf,
1092 		       const struct usb_device_id *id)
1093 {
1094 	struct usb_device *dev = interface_to_usbdev(intf);
1095 	struct usblp *usblp;
1096 	int protocol;
1097 	int retval;
1098 
1099 	/* Malloc and start initializing usblp structure so we can use it
1100 	 * directly. */
1101 	usblp = kzalloc(sizeof(struct usblp), GFP_KERNEL);
1102 	if (!usblp) {
1103 		retval = -ENOMEM;
1104 		goto abort_ret;
1105 	}
1106 	usblp->dev = dev;
1107 	mutex_init(&usblp->wmut);
1108 	mutex_init(&usblp->mut);
1109 	spin_lock_init(&usblp->lock);
1110 	init_waitqueue_head(&usblp->rwait);
1111 	init_waitqueue_head(&usblp->wwait);
1112 	init_usb_anchor(&usblp->urbs);
1113 	usblp->ifnum = intf->cur_altsetting->desc.bInterfaceNumber;
1114 	usblp->intf = intf;
1115 
1116 	/* Malloc device ID string buffer to the largest expected length,
1117 	 * since we can re-query it on an ioctl and a dynamic string
1118 	 * could change in length. */
1119 	if (!(usblp->device_id_string = kmalloc(USBLP_DEVICE_ID_SIZE, GFP_KERNEL))) {
1120 		retval = -ENOMEM;
1121 		goto abort;
1122 	}
1123 
1124 	/*
1125 	 * Allocate read buffer. We somewhat wastefully
1126 	 * malloc both regardless of bidirectionality, because the
1127 	 * alternate setting can be changed later via an ioctl.
1128 	 */
1129 	if (!(usblp->readbuf = kmalloc(USBLP_BUF_SIZE_IN, GFP_KERNEL))) {
1130 		retval = -ENOMEM;
1131 		goto abort;
1132 	}
1133 
1134 	/* Allocate buffer for printer status */
1135 	usblp->statusbuf = kmalloc(STATUS_BUF_SIZE, GFP_KERNEL);
1136 	if (!usblp->statusbuf) {
1137 		retval = -ENOMEM;
1138 		goto abort;
1139 	}
1140 
1141 	/* Lookup quirks for this printer. */
1142 	usblp->quirks = usblp_quirks(
1143 		le16_to_cpu(dev->descriptor.idVendor),
1144 		le16_to_cpu(dev->descriptor.idProduct));
1145 
1146 	/* Analyze and pick initial alternate settings and endpoints. */
1147 	protocol = usblp_select_alts(usblp);
1148 	if (protocol < 0) {
1149 		dev_dbg(&intf->dev,
1150 			"incompatible printer-class device 0x%4.4X/0x%4.4X\n",
1151 			le16_to_cpu(dev->descriptor.idVendor),
1152 			le16_to_cpu(dev->descriptor.idProduct));
1153 		retval = -ENODEV;
1154 		goto abort;
1155 	}
1156 
1157 	/* Setup the selected alternate setting and endpoints. */
1158 	if (usblp_set_protocol(usblp, protocol) < 0) {
1159 		retval = -ENODEV;	/* ->probe isn't ->ioctl */
1160 		goto abort;
1161 	}
1162 
1163 	/* Retrieve and store the device ID string. */
1164 	usblp_cache_device_id_string(usblp);
1165 
1166 #ifdef DEBUG
1167 	usblp_check_status(usblp, 0);
1168 #endif
1169 
1170 	usb_set_intfdata(intf, usblp);
1171 
1172 	usblp->present = 1;
1173 
1174 	retval = usb_register_dev(intf, &usblp_class);
1175 	if (retval) {
1176 		dev_err(&intf->dev,
1177 			"usblp: Not able to get a minor (base %u, slice default): %d\n",
1178 			USBLP_MINOR_BASE, retval);
1179 		goto abort_intfdata;
1180 	}
1181 	usblp->minor = intf->minor;
1182 	dev_info(&intf->dev,
1183 		"usblp%d: USB %sdirectional printer dev %d if %d alt %d proto %d vid 0x%4.4X pid 0x%4.4X\n",
1184 		usblp->minor, usblp->bidir ? "Bi" : "Uni", dev->devnum,
1185 		usblp->ifnum,
1186 		usblp->protocol[usblp->current_protocol].alt_setting,
1187 		usblp->current_protocol,
1188 		le16_to_cpu(usblp->dev->descriptor.idVendor),
1189 		le16_to_cpu(usblp->dev->descriptor.idProduct));
1190 
1191 	return 0;
1192 
1193 abort_intfdata:
1194 	usb_set_intfdata(intf, NULL);
1195 abort:
1196 	kfree(usblp->readbuf);
1197 	kfree(usblp->statusbuf);
1198 	kfree(usblp->device_id_string);
1199 	kfree(usblp);
1200 abort_ret:
1201 	return retval;
1202 }
1203 
1204 /*
1205  * We are a "new" style driver with usb_device_id table,
1206  * but our requirements are too intricate for simple match to handle.
1207  *
1208  * The "proto_bias" option may be used to specify the preferred protocol
1209  * for all USB printers (1=USB_CLASS_PRINTER/1/1, 2=USB_CLASS_PRINTER/1/2,
1210  * 3=USB_CLASS_PRINTER/1/3).  If the device supports the preferred protocol,
1211  * then we bind to it.
1212  *
1213  * The best interface for us is USB_CLASS_PRINTER/1/2, because it
1214  * is compatible with a stream of characters. If we find it, we bind to it.
1215  *
1216  * Note that the people from hpoj.sourceforge.net need to be able to
1217  * bind to USB_CLASS_PRINTER/1/3 (MLC/1284.4), so we provide them ioctls
1218  * for this purpose.
1219  *
1220  * Failing USB_CLASS_PRINTER/1/2, we look for USB_CLASS_PRINTER/1/3,
1221  * even though it's probably not stream-compatible, because this matches
1222  * the behaviour of the old code.
1223  *
1224  * If nothing else, we bind to USB_CLASS_PRINTER/1/1
1225  * - the unidirectional interface.
1226  */
1227 static int usblp_select_alts(struct usblp *usblp)
1228 {
1229 	struct usb_interface *if_alt;
1230 	struct usb_host_interface *ifd;
1231 	struct usb_endpoint_descriptor *epwrite, *epread;
1232 	int p, i;
1233 	int res;
1234 
1235 	if_alt = usblp->intf;
1236 
1237 	for (p = 0; p < USBLP_MAX_PROTOCOLS; p++)
1238 		usblp->protocol[p].alt_setting = -1;
1239 
1240 	/* Find out what we have. */
1241 	for (i = 0; i < if_alt->num_altsetting; i++) {
1242 		ifd = &if_alt->altsetting[i];
1243 
1244 		if (ifd->desc.bInterfaceClass != USB_CLASS_PRINTER ||
1245 		    ifd->desc.bInterfaceSubClass != 1)
1246 			if (!(usblp->quirks & USBLP_QUIRK_BAD_CLASS))
1247 				continue;
1248 
1249 		if (ifd->desc.bInterfaceProtocol < USBLP_FIRST_PROTOCOL ||
1250 		    ifd->desc.bInterfaceProtocol > USBLP_LAST_PROTOCOL)
1251 			continue;
1252 
1253 		/* Look for the expected bulk endpoints. */
1254 		if (ifd->desc.bInterfaceProtocol > 1) {
1255 			res = usb_find_common_endpoints(ifd,
1256 					&epread, &epwrite, NULL, NULL);
1257 		} else {
1258 			epread = NULL;
1259 			res = usb_find_bulk_out_endpoint(ifd, &epwrite);
1260 		}
1261 
1262 		/* Ignore buggy hardware without the right endpoints. */
1263 		if (res)
1264 			continue;
1265 
1266 		/* Turn off reads for buggy bidirectional printers. */
1267 		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 	dev_dbg(&usblp->intf->dev, "usblp%d set protocol %d\n",
1318 		usblp->minor, protocol);
1319 	return 0;
1320 }
1321 
1322 /* Retrieves and caches device ID string.
1323  * Returns length, including length bytes but not null terminator.
1324  * On error, returns a negative errno value. */
1325 static int usblp_cache_device_id_string(struct usblp *usblp)
1326 {
1327 	int err, length;
1328 
1329 	err = usblp_get_id(usblp, 0, usblp->device_id_string, USBLP_DEVICE_ID_SIZE - 1);
1330 	if (err < 0) {
1331 		dev_dbg(&usblp->intf->dev,
1332 			"usblp%d: error = %d reading IEEE-1284 Device ID string\n",
1333 			usblp->minor, err);
1334 		usblp->device_id_string[0] = usblp->device_id_string[1] = '\0';
1335 		return -EIO;
1336 	}
1337 
1338 	/* First two bytes are length in big-endian.
1339 	 * They count themselves, and we copy them into
1340 	 * the user's buffer. */
1341 	length = be16_to_cpu(*((__be16 *)usblp->device_id_string));
1342 	if (length < 2)
1343 		length = 2;
1344 	else if (length >= USBLP_DEVICE_ID_SIZE)
1345 		length = USBLP_DEVICE_ID_SIZE - 1;
1346 	usblp->device_id_string[length] = '\0';
1347 
1348 	dev_dbg(&usblp->intf->dev, "usblp%d Device ID string [len=%d]=\"%s\"\n",
1349 		usblp->minor, length, &usblp->device_id_string[2]);
1350 
1351 	return length;
1352 }
1353 
1354 static void usblp_disconnect(struct usb_interface *intf)
1355 {
1356 	struct usblp *usblp = usb_get_intfdata(intf);
1357 
1358 	usb_deregister_dev(intf, &usblp_class);
1359 
1360 	if (!usblp || !usblp->dev) {
1361 		dev_err(&intf->dev, "bogus disconnect\n");
1362 		BUG();
1363 	}
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 	usblp_unlink_urbs(usblp);
1385 #if 0 /* XXX Do we want this? What if someone is reading, should we fail? */
1386 	/* not strictly necessary, but just in case */
1387 	wake_up(&usblp->wwait);
1388 	wake_up(&usblp->rwait);
1389 #endif
1390 
1391 	return 0;
1392 }
1393 
1394 static int usblp_resume(struct usb_interface *intf)
1395 {
1396 	struct usblp *usblp = usb_get_intfdata(intf);
1397 	int r;
1398 
1399 	r = handle_bidir(usblp);
1400 
1401 	return r;
1402 }
1403 
1404 static const struct usb_device_id usblp_ids[] = {
1405 	{ USB_DEVICE_INFO(USB_CLASS_PRINTER, 1, 1) },
1406 	{ USB_DEVICE_INFO(USB_CLASS_PRINTER, 1, 2) },
1407 	{ USB_DEVICE_INFO(USB_CLASS_PRINTER, 1, 3) },
1408 	{ USB_INTERFACE_INFO(USB_CLASS_PRINTER, 1, 1) },
1409 	{ USB_INTERFACE_INFO(USB_CLASS_PRINTER, 1, 2) },
1410 	{ USB_INTERFACE_INFO(USB_CLASS_PRINTER, 1, 3) },
1411 	{ USB_DEVICE(0x04b8, 0x0202) },	/* Seiko Epson Receipt Printer M129C */
1412 	{ }						/* Terminating entry */
1413 };
1414 
1415 MODULE_DEVICE_TABLE(usb, usblp_ids);
1416 
1417 static struct usb_driver usblp_driver = {
1418 	.name =		"usblp",
1419 	.probe =	usblp_probe,
1420 	.disconnect =	usblp_disconnect,
1421 	.suspend =	usblp_suspend,
1422 	.resume =	usblp_resume,
1423 	.id_table =	usblp_ids,
1424 	.dev_groups =	usblp_groups,
1425 	.supports_autosuspend =	1,
1426 };
1427 
1428 module_usb_driver(usblp_driver);
1429 
1430 MODULE_AUTHOR(DRIVER_AUTHOR);
1431 MODULE_DESCRIPTION(DRIVER_DESC);
1432 module_param(proto_bias, int, S_IRUGO | S_IWUSR);
1433 MODULE_PARM_DESC(proto_bias, "Favourite protocol number");
1434 MODULE_LICENSE("GPL");
1435