drivers/usb/class/usblp.c

   1 /*
   2  * usblp.c  Version 0.13
   3  *
   4  * Copyright (c) 1999 Michael Gee       <michael@linuxspecific.com>
   5  * Copyright (c) 1999 Pavel Machek      <pavel@suse.cz>
   6  * Copyright (c) 2000 Randy Dunlap      <rdunlap@xenotime.net>
   7  * Copyright (c) 2000 Vojtech Pavlik    <vojtech@suse.cz>
   8  # Copyright (c) 2001 Pete Zaitcev      <zaitcev@redhat.com>
   9  # Copyright (c) 2001 David Paschal     <paschal@rcsis.com>
  10  * Copyright (c) 2006 Oliver Neukum     <oliver@neukum.name>
  11  *
  12  * USB Printer Device Class driver for USB printers and printer cables
  13  *
  14  * Sponsored by SuSE
  15  *
  16  * ChangeLog:
  17  *      v0.1 - thorough cleaning, URBification, almost a rewrite
  18  *      v0.2 - some more cleanups
  19  *      v0.3 - cleaner again, waitqueue fixes
  20  *      v0.4 - fixes in unidirectional mode
  21  *      v0.5 - add DEVICE_ID string support
  22  *      v0.6 - never time out
  23  *      v0.7 - fixed bulk-IN read and poll (David Paschal)
  24  *      v0.8 - add devfs support
  25  *      v0.9 - fix unplug-while-open paths
  26  *      v0.10- remove sleep_on, fix error on oom (oliver@neukum.org)
  27  *      v0.11 - add proto_bias option (Pete Zaitcev)
  28  *      v0.12 - add hpoj.sourceforge.net ioctls (David Paschal)
  29  *      v0.13 - alloc space for statusbuf (<status> not on stack);
  30  *              use usb_buffer_alloc() for read buf & write buf;
  31  */
  32
  33 /*
  34  * This program is free software; you can redistribute it and/or modify
  35  * it under the terms of the GNU General Public License as published by
  36  * the Free Software Foundation; either version 2 of the License, or
  37  * (at your option) any later version.
  38  *
  39  * This program is distributed in the hope that it will be useful,
  40  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  41  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  42  * GNU General Public License for more details.
  43  *
  44  * You should have received a copy of the GNU General Public License
  45  * along with this program; if not, write to the Free Software
  46  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  47  */
  48
  49 #include <linux/module.h>
  50 #include <linux/kernel.h>
  51 #include <linux/sched.h>
  52 #include <linux/signal.h>
  53 #include <linux/poll.h>
  54 #include <linux/init.h>
  55 #include <linux/slab.h>
  56 #include <linux/lp.h>
  57 #include <linux/mutex.h>
  58 #undef DEBUG
  59 #include <linux/usb.h>
  60
  61 /*
  62  * Version Information
  63  */
  64 #define DRIVER_VERSION "v0.13"
  65 #define DRIVER_AUTHOR "Michael Gee, Pavel Machek, Vojtech Pavlik, Randy Dunlap, Pete Zaitcev, David Paschal"
  66 #define DRIVER_DESC "USB Printer Device Class driver"
  67
  68 #define USBLP_BUF_SIZE          8192
  69 #define USBLP_DEVICE_ID_SIZE    1024
  70
  71 /* ioctls: */
  72 #define LPGETSTATUS             0x060b          /* same as in drivers/char/lp.c */
  73 #define IOCNR_GET_DEVICE_ID             1
  74 #define IOCNR_GET_PROTOCOLS             2
  75 #define IOCNR_SET_PROTOCOL              3
  76 #define IOCNR_HP_SET_CHANNEL            4
  77 #define IOCNR_GET_BUS_ADDRESS           5
  78 #define IOCNR_GET_VID_PID               6
  79 #define IOCNR_SOFT_RESET                7
  80 /* Get device_id string: */
  81 #define LPIOC_GET_DEVICE_ID(len) _IOC(_IOC_READ, 'P', IOCNR_GET_DEVICE_ID, len)
  82 /* The following ioctls were added for http://hpoj.sourceforge.net: */
  83 /* Get two-int array:
  84  * [0]=current protocol (1=7/1/1, 2=7/1/2, 3=7/1/3),
  85  * [1]=supported protocol mask (mask&(1<<n)!=0 means 7/1/n supported): */
  86 #define LPIOC_GET_PROTOCOLS(len) _IOC(_IOC_READ, 'P', IOCNR_GET_PROTOCOLS, len)
  87 /* Set protocol (arg: 1=7/1/1, 2=7/1/2, 3=7/1/3): */
  88 #define LPIOC_SET_PROTOCOL _IOC(_IOC_WRITE, 'P', IOCNR_SET_PROTOCOL, 0)
  89 /* Set channel number (HP Vendor-specific command): */
  90 #define LPIOC_HP_SET_CHANNEL _IOC(_IOC_WRITE, 'P', IOCNR_HP_SET_CHANNEL, 0)
  91 /* Get two-int array: [0]=bus number, [1]=device address: */
  92 #define LPIOC_GET_BUS_ADDRESS(len) _IOC(_IOC_READ, 'P', IOCNR_GET_BUS_ADDRESS, len)
  93 /* Get two-int array: [0]=vendor ID, [1]=product ID: */
  94 #define LPIOC_GET_VID_PID(len) _IOC(_IOC_READ, 'P', IOCNR_GET_VID_PID, len)
  95 /* Perform class specific soft reset */
  96 #define LPIOC_SOFT_RESET _IOC(_IOC_NONE, 'P', IOCNR_SOFT_RESET, 0);
  97
  98 /*
  99  * A DEVICE_ID string may include the printer's serial number.
 100  * It should end with a semi-colon (';').
 101  * An example from an HP 970C DeskJet printer is (this is one long string,
 102  * with the serial number changed):
 103 MFG:HEWLETT-PACKARD;MDL:DESKJET 970C;CMD:MLC,PCL,PML;CLASS:PRINTER;DESCRIPTION:Hewlett-Packard DeskJet 970C;SERN:US970CSEPROF;VSTATUS:$HB0$NC0,ff,DN,IDLE,CUT,K1,C0,DP,NR,KP000,CP027;VP:0800,FL,B0;VJ:                    ;
 104  */
 105
 106 /*
 107  * USB Printer Requests
 108  */
 109
 110 #define USBLP_REQ_GET_ID                        0x00
 111 #define USBLP_REQ_GET_STATUS                    0x01
 112 #define USBLP_REQ_RESET                         0x02
 113 #define USBLP_REQ_HP_CHANNEL_CHANGE_REQUEST     0x00    /* HP Vendor-specific */
 114
 115 #define USBLP_MINORS            16
 116 #define USBLP_MINOR_BASE        0
 117
 118 #define USBLP_WRITE_TIMEOUT     (5000)                  /* 5 seconds */
 119
 120 #define USBLP_FIRST_PROTOCOL    1
 121 #define USBLP_LAST_PROTOCOL     3
 122 #define USBLP_MAX_PROTOCOLS     (USBLP_LAST_PROTOCOL+1)
 123
 124 /*
 125  * some arbitrary status buffer size;
 126  * need a status buffer that is allocated via kmalloc(), not on stack
 127  */
 128 #define STATUS_BUF_SIZE         8
 129
 130 struct usblp {
 131         struct usb_device       *dev;                   /* USB device */
 132         struct mutex            mut;                    /* locks this struct, especially "dev" */
 133         char                    *writebuf;              /* write transfer_buffer */
 134         char                    *readbuf;               /* read transfer_buffer */
 135         char                    *statusbuf;             /* status transfer_buffer */
 136         struct urb              *readurb, *writeurb;    /* The urbs */
 137         wait_queue_head_t       wait;                   /* Zzzzz ... */
 138         int                     readcount;              /* Counter for reads */
 139         int                     ifnum;                  /* Interface number */
 140         struct usb_interface    *intf;                  /* The interface */
 141         /* Alternate-setting numbers and endpoints for each protocol
 142          * (7/1/{index=1,2,3}) that the device supports: */
 143         struct {
 144                 int                             alt_setting;
 145                 struct usb_endpoint_descriptor  *epwrite;
 146                 struct usb_endpoint_descriptor  *epread;
 147         }                       protocol[USBLP_MAX_PROTOCOLS];
 148         int                     current_protocol;
 149         int                     minor;                  /* minor number of device */
 150         int                     wcomplete;              /* writing is completed */
 151         int                     rcomplete;              /* reading is completed */
 152         unsigned int            quirks;                 /* quirks flags */
 153         unsigned char           used;                   /* True if open */
 154         unsigned char           present;                /* True if not disconnected */
 155         unsigned char           bidir;                  /* interface is bidirectional */
 156         unsigned char           sleeping;               /* interface is suspended */
 157         unsigned char           *device_id_string;      /* IEEE 1284 DEVICE ID string (ptr) */
 158                                                         /* first 2 bytes are (big-endian) length */
 159 };
 160
 161 #ifdef DEBUG
 162 static void usblp_dump(struct usblp *usblp) {
 163         int p;
 164
 165         dbg("usblp=0x%p", usblp);
 166         dbg("dev=0x%p", usblp->dev);
 167         dbg("present=%d", usblp->present);
 168         dbg("readbuf=0x%p", usblp->readbuf);
 169         dbg("writebuf=0x%p", usblp->writebuf);
 170         dbg("readurb=0x%p", usblp->readurb);
 171         dbg("writeurb=0x%p", usblp->writeurb);
 172         dbg("readcount=%d", usblp->readcount);
 173         dbg("ifnum=%d", usblp->ifnum);
 174     for (p = USBLP_FIRST_PROTOCOL; p <= USBLP_LAST_PROTOCOL; p++) {
 175         dbg("protocol[%d].alt_setting=%d", p, usblp->protocol[p].alt_setting);
 176         dbg("protocol[%d].epwrite=%p", p, usblp->protocol[p].epwrite);
 177         dbg("protocol[%d].epread=%p", p, usblp->protocol[p].epread);
 178     }
 179         dbg("current_protocol=%d", usblp->current_protocol);
 180         dbg("minor=%d", usblp->minor);
 181         dbg("wcomplete=%d", usblp->wcomplete);
 182         dbg("rcomplete=%d", usblp->rcomplete);
 183         dbg("quirks=%d", usblp->quirks);
 184         dbg("used=%d", usblp->used);
 185         dbg("bidir=%d", usblp->bidir);
 186         dbg("sleeping=%d", usblp->sleeping);
 187         dbg("device_id_string=\"%s\"",
 188                 usblp->device_id_string ?
 189                         usblp->device_id_string + 2 :
 190                         (unsigned char *)"(null)");
 191 }
 192 #endif
 193
 194 /* Quirks: various printer quirks are handled by this table & its flags. */
 195
 196 struct quirk_printer_struct {
 197         __u16 vendorId;
 198         __u16 productId;
 199         unsigned int quirks;
 200 };
 201
 202 #define USBLP_QUIRK_BIDIR       0x1     /* reports bidir but requires unidirectional mode (no INs/reads) */
 203 #define USBLP_QUIRK_USB_INIT    0x2     /* needs vendor USB init string */
 204 #define USBLP_QUIRK_BAD_CLASS   0x4     /* descriptor uses vendor-specific Class or SubClass */
 205
 206 static const struct quirk_printer_struct quirk_printers[] = {
 207         { 0x03f0, 0x0004, USBLP_QUIRK_BIDIR }, /* HP DeskJet 895C */
 208         { 0x03f0, 0x0104, USBLP_QUIRK_BIDIR }, /* HP DeskJet 880C */
 209         { 0x03f0, 0x0204, USBLP_QUIRK_BIDIR }, /* HP DeskJet 815C */
 210         { 0x03f0, 0x0304, USBLP_QUIRK_BIDIR }, /* HP DeskJet 810C/812C */
 211         { 0x03f0, 0x0404, USBLP_QUIRK_BIDIR }, /* HP DeskJet 830C */
 212         { 0x03f0, 0x0504, USBLP_QUIRK_BIDIR }, /* HP DeskJet 885C */
 213         { 0x03f0, 0x0604, USBLP_QUIRK_BIDIR }, /* HP DeskJet 840C */
 214         { 0x03f0, 0x0804, USBLP_QUIRK_BIDIR }, /* HP DeskJet 816C */
 215         { 0x03f0, 0x1104, USBLP_QUIRK_BIDIR }, /* HP Deskjet 959C */
 216         { 0x0409, 0xefbe, USBLP_QUIRK_BIDIR }, /* NEC Picty900 (HP OEM) */
 217         { 0x0409, 0xbef4, USBLP_QUIRK_BIDIR }, /* NEC Picty760 (HP OEM) */
 218         { 0x0409, 0xf0be, USBLP_QUIRK_BIDIR }, /* NEC Picty920 (HP OEM) */
 219         { 0x0409, 0xf1be, USBLP_QUIRK_BIDIR }, /* NEC Picty800 (HP OEM) */
 220         { 0x0482, 0x0010, USBLP_QUIRK_BIDIR }, /* Kyocera Mita FS 820, by zut <kernel@zut.de> */
 221         { 0x04b8, 0x0202, USBLP_QUIRK_BAD_CLASS }, /* Seiko Epson Receipt Printer M129C */
 222         { 0, 0 }
 223 };
 224
 225 static int usblp_select_alts(struct usblp *usblp);
 226 static int usblp_set_protocol(struct usblp *usblp, int protocol);
 227 static int usblp_cache_device_id_string(struct usblp *usblp);
 228
 229 /* forward reference to make our lives easier */
 230 static struct usb_driver usblp_driver;
 231 static DEFINE_MUTEX(usblp_mutex);       /* locks the existence of usblp's */
 232
 233 /*
 234  * Functions for usblp control messages.
 235  */
 236
 237 static int usblp_ctrl_msg(struct usblp *usblp, int request, int type, int dir, int recip, int value, void *buf, int len)
 238 {
 239         int retval;
 240         int index = usblp->ifnum;
 241
 242         /* High byte has the interface index.
 243            Low byte has the alternate setting.
 244          */
 245         if ((request == USBLP_REQ_GET_ID) && (type == USB_TYPE_CLASS)) {
 246           index = (usblp->ifnum<<8)|usblp->protocol[usblp->current_protocol].alt_setting;
 247         }
 248
 249         retval = usb_control_msg(usblp->dev,
 250                 dir ? usb_rcvctrlpipe(usblp->dev, 0) : usb_sndctrlpipe(usblp->dev, 0),
 251                 request, type | dir | recip, value, index, buf, len, USBLP_WRITE_TIMEOUT);
 252         dbg("usblp_control_msg: rq: 0x%02x dir: %d recip: %d value: %d idx: %d len: %#x result: %d",
 253                 request, !!dir, recip, value, index, len, retval);
 254         return retval < 0 ? retval : 0;
 255 }
 256
 257 #define usblp_read_status(usblp, status)\
 258         usblp_ctrl_msg(usblp, USBLP_REQ_GET_STATUS, USB_TYPE_CLASS, USB_DIR_IN, USB_RECIP_INTERFACE, 0, status, 1)
 259 #define usblp_get_id(usblp, config, id, maxlen)\
 260         usblp_ctrl_msg(usblp, USBLP_REQ_GET_ID, USB_TYPE_CLASS, USB_DIR_IN, USB_RECIP_INTERFACE, config, id, maxlen)
 261 #define usblp_reset(usblp)\
 262         usblp_ctrl_msg(usblp, USBLP_REQ_RESET, USB_TYPE_CLASS, USB_DIR_OUT, USB_RECIP_OTHER, 0, NULL, 0)
 263
 264 #define usblp_hp_channel_change_request(usblp, channel, buffer) \
 265         usblp_ctrl_msg(usblp, USBLP_REQ_HP_CHANNEL_CHANGE_REQUEST, USB_TYPE_VENDOR, USB_DIR_IN, USB_RECIP_INTERFACE, channel, buffer, 1)
 266
 267 /*
 268  * See the description for usblp_select_alts() below for the usage
 269  * explanation.  Look into your /proc/bus/usb/devices and dmesg in
 270  * case of any trouble.
 271  */
 272 static int proto_bias = -1;
 273
 274 /*
 275  * URB callback.
 276  */
 277
 278 static void usblp_bulk_read(struct urb *urb)
 279 {
 280         struct usblp *usblp = urb->context;
 281
 282         if (unlikely(!usblp || !usblp->dev || !usblp->used))
 283                 return;
 284
 285         if (unlikely(!usblp->present))
 286                 goto unplug;
 287         if (unlikely(urb->status))
 288                 warn("usblp%d: nonzero read/write bulk status received: %d",
 289                         usblp->minor, urb->status);
 290         usblp->rcomplete = 1;
 291 unplug:
 292         wake_up_interruptible(&usblp->wait);
 293 }
 294
 295 static void usblp_bulk_write(struct urb *urb)
 296 {
 297         struct usblp *usblp = urb->context;
 298
 299         if (unlikely(!usblp || !usblp->dev || !usblp->used))
 300                 return;
 301         if (unlikely(!usblp->present))
 302                 goto unplug;
 303         if (unlikely(urb->status))
 304                 warn("usblp%d: nonzero read/write bulk status received: %d",
 305                         usblp->minor, urb->status);
 306         usblp->wcomplete = 1;
 307 unplug:
 308         wake_up_interruptible(&usblp->wait);
 309 }
 310
 311 /*
 312  * Get and print printer errors.
 313  */
 314
 315 static const char *usblp_messages[] = { "ok", "out of paper", "off-line", "on fire" };
 316
 317 static int usblp_check_status(struct usblp *usblp, int err)
 318 {
 319         unsigned char status, newerr = 0;
 320         int error;
 321
 322         error = usblp_read_status (usblp, usblp->statusbuf);
 323         if (error < 0) {
 324                 if (printk_ratelimit())
 325                         err("usblp%d: error %d reading printer status",
 326                                 usblp->minor, error);
 327                 return 0;
 328         }
 329
 330         status = *usblp->statusbuf;
 331
 332         if (~status & LP_PERRORP)
 333                 newerr = 3;
 334         if (status & LP_POUTPA)
 335                 newerr = 1;
 336         if (~status & LP_PSELECD)
 337                 newerr = 2;
 338
 339         if (newerr != err)
 340                 info("usblp%d: %s", usblp->minor, usblp_messages[newerr]);
 341
 342         return newerr;
 343 }
 344
 345 static int handle_bidir (struct usblp *usblp)
 346 {
 347         if (usblp->bidir && usblp->used && !usblp->sleeping) {
 348                 usblp->readcount = 0;
 349                 usblp->readurb->dev = usblp->dev;
 350                 if (usb_submit_urb(usblp->readurb, GFP_KERNEL) < 0)
 351                         return -EIO;
 352         }
 353
 354         return 0;
 355 }
 356
 357 /*
 358  * File op functions.
 359  */
 360
 361 static int usblp_open(struct inode *inode, struct file *file)
 362 {
 363         int minor = iminor(inode);
 364         struct usblp *usblp;
 365         struct usb_interface *intf;
 366         int retval;
 367
 368         if (minor < 0)
 369                 return -ENODEV;
 370
 371         mutex_lock (&usblp_mutex);
 372
 373         retval = -ENODEV;
 374         intf = usb_find_interface(&usblp_driver, minor);
 375         if (!intf) {
 376                 goto out;
 377         }
 378         usblp = usb_get_intfdata (intf);
 379         if (!usblp || !usblp->dev || !usblp->present)
 380                 goto out;
 381
 382         retval = -EBUSY;
 383         if (usblp->used)
 384                 goto out;
 385
 386         /*
 387          * TODO: need to implement LP_ABORTOPEN + O_NONBLOCK as in drivers/char/lp.c ???
 388          * This is #if 0-ed because we *don't* want to fail an open
 389          * just because the printer is off-line.
 390          */
 391 #if 0
 392         if ((retval = usblp_check_status(usblp, 0))) {
 393                 retval = retval > 1 ? -EIO : -ENOSPC;
 394                 goto out;
 395         }
 396 #else
 397         retval = 0;
 398 #endif
 399
 400         retval = usb_autopm_get_interface(intf);
 401         if (retval < 0)
 402                 goto out;
 403         usblp->used = 1;
 404         file->private_data = usblp;
 405
 406         usblp->writeurb->transfer_buffer_length = 0;
 407         usblp->wcomplete = 1; /* we begin writeable */
 408         usblp->rcomplete = 0;
 409         usblp->writeurb->status = 0;
 410         usblp->readurb->status = 0;
 411
 412         if (handle_bidir(usblp) < 0) {
 413                 usblp->used = 0;
 414                 file->private_data = NULL;
 415                 retval = -EIO;
 416         }
 417 out:
 418         mutex_unlock (&usblp_mutex);
 419         return retval;
 420 }
 421
 422 static void usblp_cleanup (struct usblp *usblp)
 423 {
 424         info("usblp%d: removed", usblp->minor);
 425
 426         kfree (usblp->device_id_string);
 427         kfree (usblp->statusbuf);
 428         usb_free_urb(usblp->writeurb);
 429         usb_free_urb(usblp->readurb);
 430         kfree (usblp);
 431 }
 432
 433 static void usblp_unlink_urbs(struct usblp *usblp)
 434 {
 435         usb_kill_urb(usblp->writeurb);
 436         if (usblp->bidir)
 437                 usb_kill_urb(usblp->readurb);
 438 }
 439
 440 static int usblp_release(struct inode *inode, struct file *file)
 441 {
 442         struct usblp *usblp = file->private_data;
 443
 444         mutex_lock (&usblp_mutex);
 445         usblp->used = 0;
 446         if (usblp->present) {
 447                 usblp_unlink_urbs(usblp);
 448                 usb_autopm_put_interface(usblp->intf);
 449         } else          /* finish cleanup from disconnect */
 450                 usblp_cleanup (usblp);
 451         mutex_unlock (&usblp_mutex);
 452         return 0;
 453 }
 454
 455 /* No kernel lock - fine */
 456 static unsigned int usblp_poll(struct file *file, struct poll_table_struct *wait)
 457 {
 458         struct usblp *usblp = file->private_data;
 459         poll_wait(file, &usblp->wait, wait);
 460         return ((!usblp->bidir || !usblp->rcomplete) ? 0 : POLLIN  | POLLRDNORM)
 461                                | (!usblp->wcomplete ? 0 : POLLOUT | POLLWRNORM);
 462 }
 463
 464 static long usblp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 465 {
 466         struct usblp *usblp = file->private_data;
 467         int length, err, i;
 468         unsigned char newChannel;
 469         int status;
 470         int twoints[2];
 471         int retval = 0;
 472
 473         mutex_lock (&usblp->mut);
 474         if (!usblp->present) {
 475                 retval = -ENODEV;
 476                 goto done;
 477         }
 478
 479         if (usblp->sleeping) {
 480                 retval = -ENODEV;
 481                 goto done;
 482         }
 483
 484         dbg("usblp_ioctl: cmd=0x%x (%c nr=%d len=%d dir=%d)", cmd, _IOC_TYPE(cmd),
 485                 _IOC_NR(cmd), _IOC_SIZE(cmd), _IOC_DIR(cmd) );
 486
 487         if (_IOC_TYPE(cmd) == 'P')      /* new-style ioctl number */
 488
 489                 switch (_IOC_NR(cmd)) {
 490
 491                         case IOCNR_GET_DEVICE_ID: /* get the DEVICE_ID string */
 492                                 if (_IOC_DIR(cmd) != _IOC_READ) {
 493                                         retval = -EINVAL;
 494                                         goto done;
 495                                 }
 496
 497                                 length = usblp_cache_device_id_string(usblp);
 498                                 if (length < 0) {
 499                                         retval = length;
 500                                         goto done;
 501                                 }
 502                                 if (length > _IOC_SIZE(cmd))
 503                                         length = _IOC_SIZE(cmd); /* truncate */
 504
 505                                 if (copy_to_user((void __user *) arg,
 506                                                 usblp->device_id_string,
 507                                                 (unsigned long) length)) {
 508                                         retval = -EFAULT;
 509                                         goto done;
 510                                 }
 511
 512                                 break;
 513
 514                         case IOCNR_GET_PROTOCOLS:
 515                                 if (_IOC_DIR(cmd) != _IOC_READ ||
 516                                     _IOC_SIZE(cmd) < sizeof(twoints)) {
 517                                         retval = -EINVAL;
 518                                         goto done;
 519                                 }
 520
 521                                 twoints[0] = usblp->current_protocol;
 522                                 twoints[1] = 0;
 523                                 for (i = USBLP_FIRST_PROTOCOL;
 524                                      i <= USBLP_LAST_PROTOCOL; i++) {
 525                                         if (usblp->protocol[i].alt_setting >= 0)
 526                                                 twoints[1] |= (1<<i);
 527                                 }
 528
 529                                 if (copy_to_user((void __user *)arg,
 530                                                 (unsigned char *)twoints,
 531                                                 sizeof(twoints))) {
 532                                         retval = -EFAULT;
 533                                         goto done;
 534                                 }
 535
 536                                 break;
 537
 538                         case IOCNR_SET_PROTOCOL:
 539                                 if (_IOC_DIR(cmd) != _IOC_WRITE) {
 540                                         retval = -EINVAL;
 541                                         goto done;
 542                                 }
 543
 544 #ifdef DEBUG
 545                                 if (arg == -10) {
 546                                         usblp_dump(usblp);
 547                                         break;
 548                                 }
 549 #endif
 550
 551                                 usblp_unlink_urbs(usblp);
 552                                 retval = usblp_set_protocol(usblp, arg);
 553                                 if (retval < 0) {
 554                                         usblp_set_protocol(usblp,
 555                                                 usblp->current_protocol);
 556                                 }
 557                                 break;
 558
 559                         case IOCNR_HP_SET_CHANNEL:
 560                                 if (_IOC_DIR(cmd) != _IOC_WRITE ||
 561                                     le16_to_cpu(usblp->dev->descriptor.idVendor) != 0x03F0 ||
 562                                     usblp->quirks & USBLP_QUIRK_BIDIR) {
 563                                         retval = -EINVAL;
 564                                         goto done;
 565                                 }
 566
 567                                 err = usblp_hp_channel_change_request(usblp,
 568                                         arg, &newChannel);
 569                                 if (err < 0) {
 570                                         err("usblp%d: error = %d setting "
 571                                                 "HP channel",
 572                                                 usblp->minor, err);
 573                                         retval = -EIO;
 574                                         goto done;
 575                                 }
 576
 577                                 dbg("usblp%d requested/got HP channel %ld/%d",
 578                                         usblp->minor, arg, newChannel);
 579                                 break;
 580
 581                         case IOCNR_GET_BUS_ADDRESS:
 582                                 if (_IOC_DIR(cmd) != _IOC_READ ||
 583                                     _IOC_SIZE(cmd) < sizeof(twoints)) {
 584                                         retval = -EINVAL;
 585                                         goto done;
 586                                 }
 587
 588                                 twoints[0] = usblp->dev->bus->busnum;
 589                                 twoints[1] = usblp->dev->devnum;
 590                                 if (copy_to_user((void __user *)arg,
 591                                                 (unsigned char *)twoints,
 592                                                 sizeof(twoints))) {
 593                                         retval = -EFAULT;
 594                                         goto done;
 595                                 }
 596
 597                                 dbg("usblp%d is bus=%d, device=%d",
 598                                         usblp->minor, twoints[0], twoints[1]);
 599                                 break;
 600
 601                         case IOCNR_GET_VID_PID:
 602                                 if (_IOC_DIR(cmd) != _IOC_READ ||
 603                                     _IOC_SIZE(cmd) < sizeof(twoints)) {
 604                                         retval = -EINVAL;
 605                                         goto done;
 606                                 }
 607
 608                                 twoints[0] = le16_to_cpu(usblp->dev->descriptor.idVendor);
 609                                 twoints[1] = le16_to_cpu(usblp->dev->descriptor.idProduct);
 610                                 if (copy_to_user((void __user *)arg,
 611                                                 (unsigned char *)twoints,
 612                                                 sizeof(twoints))) {
 613                                         retval = -EFAULT;
 614                                         goto done;
 615                                 }
 616
 617                                 dbg("usblp%d is VID=0x%4.4X, PID=0x%4.4X",
 618                                         usblp->minor, twoints[0], twoints[1]);
 619                                 break;
 620
 621                         case IOCNR_SOFT_RESET:
 622                                 if (_IOC_DIR(cmd) != _IOC_NONE) {
 623                                         retval = -EINVAL;
 624                                         goto done;
 625                                 }
 626                                 retval = usblp_reset(usblp);
 627                                 break;
 628                         default:
 629                                 retval = -ENOTTY;
 630                 }
 631         else    /* old-style ioctl value */
 632                 switch (cmd) {
 633
 634                         case LPGETSTATUS:
 635                                 if (usblp_read_status(usblp, usblp->statusbuf)) {
 636                                         if (printk_ratelimit())
 637                                                 err("usblp%d: failed reading printer status",
 638                                                         usblp->minor);
 639                                         retval = -EIO;
 640                                         goto done;
 641                                 }
 642                                 status = *usblp->statusbuf;
 643                                 if (copy_to_user ((void __user *)arg, &status, sizeof(int)))
 644                                         retval = -EFAULT;
 645                                 break;
 646
 647                         default:
 648                                 retval = -ENOTTY;
 649                 }
 650
 651 done:
 652         mutex_unlock (&usblp->mut);
 653         return retval;
 654 }
 655
 656 static ssize_t usblp_write(struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
 657 {
 658         struct usblp *usblp = file->private_data;
 659         int timeout, intr, rv, err = 0, transfer_length = 0;
 660         size_t writecount = 0;
 661
 662         while (writecount < count) {
 663                 if (!usblp->wcomplete) {
 664                         barrier();
 665                         if (file->f_flags & O_NONBLOCK) {
 666                                 writecount += transfer_length;
 667                                 return writecount ? writecount : -EAGAIN;
 668                         }
 669
 670                         timeout = USBLP_WRITE_TIMEOUT;
 671
 672                         rv = wait_event_interruptible_timeout(usblp->wait, usblp->wcomplete || !usblp->present , timeout);
 673                         if (rv < 0)
 674                                 return writecount ? writecount : -EINTR;
 675                 }
 676                 intr = mutex_lock_interruptible (&usblp->mut);
 677                 if (intr)
 678                         return writecount ? writecount : -EINTR;
 679                 if (!usblp->present) {
 680                         mutex_unlock (&usblp->mut);
 681                         return -ENODEV;
 682                 }
 683
 684                 if (usblp->sleeping) {
 685                         mutex_unlock (&usblp->mut);
 686                         return writecount ? writecount : -ENODEV;
 687                 }
 688
 689                 if (usblp->writeurb->status != 0) {
 690                         if (usblp->quirks & USBLP_QUIRK_BIDIR) {
 691                                 if (!usblp->wcomplete)
 692                                         err("usblp%d: error %d writing to printer",
 693                                                 usblp->minor, usblp->writeurb->status);
 694                                 err = usblp->writeurb->status;
 695                         } else
 696                                 err = usblp_check_status(usblp, err);
 697                         mutex_unlock (&usblp->mut);
 698
 699                         /* if the fault was due to disconnect, let khubd's
 700                          * call to usblp_disconnect() grab usblp->mut ...
 701                          */
 702                         schedule ();
 703                         continue;
 704                 }
 705
 706                 /* We must increment writecount here, and not at the
 707                  * end of the loop. Otherwise, the final loop iteration may
 708                  * be skipped, leading to incomplete printer output.
 709                  */
 710                 writecount += transfer_length;
 711                 if (writecount == count) {
 712                         mutex_unlock(&usblp->mut);
 713                         break;
 714                 }
 715
 716                 transfer_length=(count - writecount);
 717                 if (transfer_length > USBLP_BUF_SIZE)
 718                         transfer_length = USBLP_BUF_SIZE;
 719
 720                 usblp->writeurb->transfer_buffer_length = transfer_length;
 721
 722                 if (copy_from_user(usblp->writeurb->transfer_buffer,
 723                                    buffer + writecount, transfer_length)) {
 724                         mutex_unlock(&usblp->mut);
 725                         return writecount ? writecount : -EFAULT;
 726                 }
 727
 728                 usblp->writeurb->dev = usblp->dev;
 729                 usblp->wcomplete = 0;
 730                 err = usb_submit_urb(usblp->writeurb, GFP_KERNEL);
 731                 if (err) {
 732                         usblp->wcomplete = 1;
 733                         if (err != -ENOMEM)
 734                                 count = -EIO;
 735                         else
 736                                 count = writecount ? writecount : -ENOMEM;
 737                         mutex_unlock (&usblp->mut);
 738                         break;
 739                 }
 740                 mutex_unlock (&usblp->mut);
 741         }
 742
 743         return count;
 744 }
 745
 746 static ssize_t usblp_read(struct file *file, char __user *buffer, size_t count, loff_t *ppos)
 747 {
 748         struct usblp *usblp = file->private_data;
 749         int rv, intr;
 750
 751         if (!usblp->bidir)
 752                 return -EINVAL;
 753
 754         intr = mutex_lock_interruptible (&usblp->mut);
 755         if (intr)
 756                 return -EINTR;
 757         if (!usblp->present) {
 758                 count = -ENODEV;
 759                 goto done;
 760         }
 761
 762         if (!usblp->rcomplete) {
 763                 barrier();
 764
 765                 if (file->f_flags & O_NONBLOCK) {
 766                         count = -EAGAIN;
 767                         goto done;
 768                 }
 769                 mutex_unlock(&usblp->mut);
 770                 rv = wait_event_interruptible(usblp->wait, usblp->rcomplete || !usblp->present);
 771                 mutex_lock(&usblp->mut);
 772                 if (rv < 0) {
 773                         count = -EINTR;
 774                         goto done;
 775                 }
 776         }
 777
 778         if (!usblp->present) {
 779                 count = -ENODEV;
 780                 goto done;
 781         }
 782
 783         if (usblp->sleeping) {
 784                 count = -ENODEV;
 785                 goto done;
 786         }
 787
 788         if (usblp->readurb->status) {
 789                 err("usblp%d: error %d reading from printer",
 790                         usblp->minor, usblp->readurb->status);
 791                 usblp->readurb->dev = usblp->dev;
 792                 usblp->readcount = 0;
 793                 usblp->rcomplete = 0;
 794                 if (usb_submit_urb(usblp->readurb, GFP_KERNEL) < 0)
 795                         dbg("error submitting urb");
 796                 count = -EIO;
 797                 goto done;
 798         }
 799
 800         count = count < usblp->readurb->actual_length - usblp->readcount ?
 801                 count : usblp->readurb->actual_length - usblp->readcount;
 802
 803         if (copy_to_user(buffer, usblp->readurb->transfer_buffer + usblp->readcount, count)) {
 804                 count = -EFAULT;
 805                 goto done;
 806         }
 807
 808         if ((usblp->readcount += count) == usblp->readurb->actual_length) {
 809                 usblp->readcount = 0;
 810                 usblp->readurb->dev = usblp->dev;
 811                 usblp->rcomplete = 0;
 812                 if (usb_submit_urb(usblp->readurb, GFP_KERNEL)) {
 813                         count = -EIO;
 814                         goto done;
 815                 }
 816         }
 817
 818 done:
 819         mutex_unlock (&usblp->mut);
 820         return count;
 821 }
 822
 823 /*
 824  * Checks for printers that have quirks, such as requiring unidirectional
 825  * communication but reporting bidirectional; currently some HP printers
 826  * have this flaw (HP 810, 880, 895, etc.), or needing an init string
 827  * sent at each open (like some Epsons).
 828  * Returns 1 if found, 0 if not found.
 829  *
 830  * HP recommended that we use the bidirectional interface but
 831  * don't attempt any bulk IN transfers from the IN endpoint.
 832  * Here's some more detail on the problem:
 833  * The problem is not that it isn't bidirectional though. The problem
 834  * is that if you request a device ID, or status information, while
 835  * the buffers are full, the return data will end up in the print data
 836  * buffer. For example if you make sure you never request the device ID
 837  * while you are sending print data, and you don't try to query the
 838  * printer status every couple of milliseconds, you will probably be OK.
 839  */
 840 static unsigned int usblp_quirks (__u16 vendor, __u16 product)
 841 {
 842         int i;
 843
 844         for (i = 0; quirk_printers[i].vendorId; i++) {
 845                 if (vendor == quirk_printers[i].vendorId &&
 846                     product == quirk_printers[i].productId)
 847                         return quirk_printers[i].quirks;
 848         }
 849         return 0;
 850 }
 851
 852 static const struct file_operations usblp_fops = {
 853         .owner =        THIS_MODULE,
 854         .read =         usblp_read,
 855         .write =        usblp_write,
 856         .poll =         usblp_poll,
 857         .unlocked_ioctl =       usblp_ioctl,
 858         .compat_ioctl =         usblp_ioctl,
 859         .open =         usblp_open,
 860         .release =      usblp_release,
 861 };
 862
 863 static struct usb_class_driver usblp_class = {
 864         .name =         "lp%d",
 865         .fops =         &usblp_fops,
 866         .minor_base =   USBLP_MINOR_BASE,
 867 };
 868
 869 static ssize_t usblp_show_ieee1284_id(struct device *dev, struct device_attribute *attr, char *buf)
 870 {
 871         struct usb_interface *intf = to_usb_interface(dev);
 872         struct usblp *usblp = usb_get_intfdata (intf);
 873
 874         if (usblp->device_id_string[0] == 0 &&
 875             usblp->device_id_string[1] == 0)
 876                 return 0;
 877
 878         return sprintf(buf, "%s", usblp->device_id_string+2);
 879 }
 880
 881 static DEVICE_ATTR(ieee1284_id, S_IRUGO, usblp_show_ieee1284_id, NULL);
 882
 883 static int usblp_probe(struct usb_interface *intf,
 884                        const struct usb_device_id *id)
 885 {
 886         struct usb_device *dev = interface_to_usbdev (intf);
 887         struct usblp *usblp = NULL;
 888         int protocol;
 889         int retval;
 890
 891         /* Malloc and start initializing usblp structure so we can use it
 892          * directly. */
 893         if (!(usblp = kzalloc(sizeof(struct usblp), GFP_KERNEL))) {
 894                 err("out of memory for usblp");
 895                 goto abort;
 896         }
 897         usblp->dev = dev;
 898         mutex_init (&usblp->mut);
 899         init_waitqueue_head(&usblp->wait);
 900         usblp->ifnum = intf->cur_altsetting->desc.bInterfaceNumber;
 901         usblp->intf = intf;
 902
 903         usblp->writeurb = usb_alloc_urb(0, GFP_KERNEL);
 904         if (!usblp->writeurb) {
 905                 err("out of memory");
 906                 goto abort;
 907         }
 908         usblp->readurb = usb_alloc_urb(0, GFP_KERNEL);
 909         if (!usblp->readurb) {
 910                 err("out of memory");
 911                 goto abort;
 912         }
 913
 914         /* Malloc device ID string buffer to the largest expected length,
 915          * since we can re-query it on an ioctl and a dynamic string
 916          * could change in length. */
 917         if (!(usblp->device_id_string = kmalloc(USBLP_DEVICE_ID_SIZE, GFP_KERNEL))) {
 918                 err("out of memory for device_id_string");
 919                 goto abort;
 920         }
 921
 922         usblp->writebuf = usblp->readbuf = NULL;
 923         usblp->writeurb->transfer_flags = URB_NO_TRANSFER_DMA_MAP;
 924         usblp->readurb->transfer_flags = URB_NO_TRANSFER_DMA_MAP;
 925         /* Malloc write & read buffers.  We somewhat wastefully
 926          * malloc both regardless of bidirectionality, because the
 927          * alternate setting can be changed later via an ioctl. */
 928         if (!(usblp->writebuf = usb_buffer_alloc(dev, USBLP_BUF_SIZE,
 929                                 GFP_KERNEL, &usblp->writeurb->transfer_dma))) {
 930                 err("out of memory for write buf");
 931                 goto abort;
 932         }
 933         if (!(usblp->readbuf = usb_buffer_alloc(dev, USBLP_BUF_SIZE,
 934                                 GFP_KERNEL, &usblp->readurb->transfer_dma))) {
 935                 err("out of memory for read buf");
 936                 goto abort;
 937         }
 938
 939         /* Allocate buffer for printer status */
 940         usblp->statusbuf = kmalloc(STATUS_BUF_SIZE, GFP_KERNEL);
 941         if (!usblp->statusbuf) {
 942                 err("out of memory for statusbuf");
 943                 goto abort;
 944         }
 945
 946         /* Lookup quirks for this printer. */
 947         usblp->quirks = usblp_quirks(
 948                 le16_to_cpu(dev->descriptor.idVendor),
 949                 le16_to_cpu(dev->descriptor.idProduct));
 950
 951         /* Analyze and pick initial alternate settings and endpoints. */
 952         protocol = usblp_select_alts(usblp);
 953         if (protocol < 0) {
 954                 dbg("incompatible printer-class device 0x%4.4X/0x%4.4X",
 955                         le16_to_cpu(dev->descriptor.idVendor),
 956                         le16_to_cpu(dev->descriptor.idProduct));
 957                 goto abort;
 958         }
 959
 960         /* Setup the selected alternate setting and endpoints. */
 961         if (usblp_set_protocol(usblp, protocol) < 0)
 962                 goto abort;
 963
 964         /* Retrieve and store the device ID string. */
 965         usblp_cache_device_id_string(usblp);
 966         retval = device_create_file(&intf->dev, &dev_attr_ieee1284_id);
 967         if (retval)
 968                 goto abort_intfdata;
 969
 970 #ifdef DEBUG
 971         usblp_check_status(usblp, 0);
 972 #endif
 973
 974         usb_set_intfdata (intf, usblp);
 975
 976         usblp->present = 1;
 977
 978         retval = usb_register_dev(intf, &usblp_class);
 979         if (retval) {
 980                 err("Not able to get a minor for this device.");
 981                 goto abort_intfdata;
 982         }
 983         usblp->minor = intf->minor;
 984         info("usblp%d: USB %sdirectional printer dev %d "
 985                 "if %d alt %d proto %d vid 0x%4.4X pid 0x%4.4X",
 986                 usblp->minor, usblp->bidir ? "Bi" : "Uni", dev->devnum,
 987                 usblp->ifnum,
 988                 usblp->protocol[usblp->current_protocol].alt_setting,
 989                 usblp->current_protocol,
 990                 le16_to_cpu(usblp->dev->descriptor.idVendor),
 991                 le16_to_cpu(usblp->dev->descriptor.idProduct));
 992
 993         return 0;
 994
 995 abort_intfdata:
 996         usb_set_intfdata (intf, NULL);
 997         device_remove_file(&intf->dev, &dev_attr_ieee1284_id);
 998 abort:
 999         if (usblp) {
1000                 if (usblp->writebuf)
1001                         usb_buffer_free (usblp->dev, USBLP_BUF_SIZE,
1002                                 usblp->writebuf, usblp->writeurb->transfer_dma);
1003                 if (usblp->readbuf)
1004                         usb_buffer_free (usblp->dev, USBLP_BUF_SIZE,
1005                                 usblp->readbuf, usblp->readurb->transfer_dma);
1006                 kfree(usblp->statusbuf);
1007                 kfree(usblp->device_id_string);
1008                 usb_free_urb(usblp->writeurb);
1009                 usb_free_urb(usblp->readurb);
1010                 kfree(usblp);
1011         }
1012         return -EIO;
1013 }
1014
1015 /*
1016  * We are a "new" style driver with usb_device_id table,
1017  * but our requirements are too intricate for simple match to handle.
1018  *
1019  * The "proto_bias" option may be used to specify the preferred protocol
1020  * for all USB printers (1=7/1/1, 2=7/1/2, 3=7/1/3).  If the device
1021  * supports the preferred protocol, then we bind to it.
1022  *
1023  * The best interface for us is 7/1/2, because it is compatible
1024  * with a stream of characters. If we find it, we bind to it.
1025  *
1026  * Note that the people from hpoj.sourceforge.net need to be able to
1027  * bind to 7/1/3 (MLC/1284.4), so we provide them ioctls for this purpose.
1028  *
1029  * Failing 7/1/2, we look for 7/1/3, even though it's probably not
1030  * stream-compatible, because this matches the behaviour of the old code.
1031  *
1032  * If nothing else, we bind to 7/1/1 - the unidirectional interface.
1033  */
1034 static int usblp_select_alts(struct usblp *usblp)
1035 {
1036         struct usb_interface *if_alt;
1037         struct usb_host_interface *ifd;
1038         struct usb_endpoint_descriptor *epd, *epwrite, *epread;
1039         int p, i, e;
1040
1041         if_alt = usblp->intf;
1042
1043         for (p = 0; p < USBLP_MAX_PROTOCOLS; p++)
1044                 usblp->protocol[p].alt_setting = -1;
1045
1046         /* Find out what we have. */
1047         for (i = 0; i < if_alt->num_altsetting; i++) {
1048                 ifd = &if_alt->altsetting[i];
1049
1050                 if (ifd->desc.bInterfaceClass != 7 || ifd->desc.bInterfaceSubClass != 1)
1051                         if (!(usblp->quirks & USBLP_QUIRK_BAD_CLASS))
1052                                 continue;
1053
1054                 if (ifd->desc.bInterfaceProtocol < USBLP_FIRST_PROTOCOL ||
1055                     ifd->desc.bInterfaceProtocol > USBLP_LAST_PROTOCOL)
1056                         continue;
1057
1058                 /* Look for bulk OUT and IN endpoints. */
1059                 epwrite = epread = NULL;
1060                 for (e = 0; e < ifd->desc.bNumEndpoints; e++) {
1061                         epd = &ifd->endpoint[e].desc;
1062
1063                         if (usb_endpoint_is_bulk_out(epd))
1064                                 if (!epwrite)
1065                                         epwrite = epd;
1066
1067                         if (usb_endpoint_is_bulk_in(epd))
1068                                 if (!epread)
1069                                         epread = epd;
1070                 }
1071
1072                 /* Ignore buggy hardware without the right endpoints. */
1073                 if (!epwrite || (ifd->desc.bInterfaceProtocol > 1 && !epread))
1074                         continue;
1075
1076                 /* Turn off reads for 7/1/1 (unidirectional) interfaces
1077                  * and buggy bidirectional printers. */
1078                 if (ifd->desc.bInterfaceProtocol == 1) {
1079                         epread = NULL;
1080                 } else if (usblp->quirks & USBLP_QUIRK_BIDIR) {
1081                         info("Disabling reads from problem bidirectional "
1082                                 "printer on usblp%d", usblp->minor);
1083                         epread = NULL;
1084                 }
1085
1086                 usblp->protocol[ifd->desc.bInterfaceProtocol].alt_setting =
1087                                 ifd->desc.bAlternateSetting;
1088                 usblp->protocol[ifd->desc.bInterfaceProtocol].epwrite = epwrite;
1089                 usblp->protocol[ifd->desc.bInterfaceProtocol].epread = epread;
1090         }
1091
1092         /* If our requested protocol is supported, then use it. */
1093         if (proto_bias >= USBLP_FIRST_PROTOCOL &&
1094             proto_bias <= USBLP_LAST_PROTOCOL &&
1095             usblp->protocol[proto_bias].alt_setting != -1)
1096                 return proto_bias;
1097
1098         /* Ordering is important here. */
1099         if (usblp->protocol[2].alt_setting != -1)
1100                 return 2;
1101         if (usblp->protocol[1].alt_setting != -1)
1102                 return 1;
1103         if (usblp->protocol[3].alt_setting != -1)
1104                 return 3;
1105
1106         /* If nothing is available, then don't bind to this device. */
1107         return -1;
1108 }
1109
1110 static int usblp_set_protocol(struct usblp *usblp, int protocol)
1111 {
1112         int r, alts;
1113
1114         if (protocol < USBLP_FIRST_PROTOCOL || protocol > USBLP_LAST_PROTOCOL)
1115                 return -EINVAL;
1116
1117         alts = usblp->protocol[protocol].alt_setting;
1118         if (alts < 0)
1119                 return -EINVAL;
1120         r = usb_set_interface(usblp->dev, usblp->ifnum, alts);
1121         if (r < 0) {
1122                 err("can't set desired altsetting %d on interface %d",
1123                         alts, usblp->ifnum);
1124                 return r;
1125         }
1126
1127         usb_fill_bulk_urb(usblp->writeurb, usblp->dev,
1128                 usb_sndbulkpipe(usblp->dev,
1129                   usblp->protocol[protocol].epwrite->bEndpointAddress),
1130                 usblp->writebuf, 0,
1131                 usblp_bulk_write, usblp);
1132
1133         usblp->bidir = (usblp->protocol[protocol].epread != NULL);
1134         if (usblp->bidir)
1135                 usb_fill_bulk_urb(usblp->readurb, usblp->dev,
1136                         usb_rcvbulkpipe(usblp->dev,
1137                           usblp->protocol[protocol].epread->bEndpointAddress),
1138                         usblp->readbuf, USBLP_BUF_SIZE,
1139                         usblp_bulk_read, usblp);
1140
1141         usblp->current_protocol = protocol;
1142         dbg("usblp%d set protocol %d", usblp->minor, protocol);
1143         return 0;
1144 }
1145
1146 /* Retrieves and caches device ID string.
1147  * Returns length, including length bytes but not null terminator.
1148  * On error, returns a negative errno value. */
1149 static int usblp_cache_device_id_string(struct usblp *usblp)
1150 {
1151         int err, length;
1152
1153         err = usblp_get_id(usblp, 0, usblp->device_id_string, USBLP_DEVICE_ID_SIZE - 1);
1154         if (err < 0) {
1155                 dbg("usblp%d: error = %d reading IEEE-1284 Device ID string",
1156                         usblp->minor, err);
1157                 usblp->device_id_string[0] = usblp->device_id_string[1] = '\0';
1158                 return -EIO;
1159         }
1160
1161         /* First two bytes are length in big-endian.
1162          * They count themselves, and we copy them into
1163          * the user's buffer. */
1164         length = be16_to_cpu(*((__be16 *)usblp->device_id_string));
1165         if (length < 2)
1166                 length = 2;
1167         else if (length >= USBLP_DEVICE_ID_SIZE)
1168                 length = USBLP_DEVICE_ID_SIZE - 1;
1169         usblp->device_id_string[length] = '\0';
1170
1171         dbg("usblp%d Device ID string [len=%d]=\"%s\"",
1172                 usblp->minor, length, &usblp->device_id_string[2]);
1173
1174         return length;
1175 }
1176
1177 static void usblp_disconnect(struct usb_interface *intf)
1178 {
1179         struct usblp *usblp = usb_get_intfdata (intf);
1180
1181         usb_deregister_dev(intf, &usblp_class);
1182
1183         if (!usblp || !usblp->dev) {
1184                 err("bogus disconnect");
1185                 BUG ();
1186         }
1187
1188         device_remove_file(&intf->dev, &dev_attr_ieee1284_id);
1189
1190         mutex_lock (&usblp_mutex);
1191         mutex_lock (&usblp->mut);
1192         usblp->present = 0;
1193         usb_set_intfdata (intf, NULL);
1194
1195         usblp_unlink_urbs(usblp);
1196         usb_buffer_free (usblp->dev, USBLP_BUF_SIZE,
1197                         usblp->writebuf, usblp->writeurb->transfer_dma);
1198         usb_buffer_free (usblp->dev, USBLP_BUF_SIZE,
1199                         usblp->readbuf, usblp->readurb->transfer_dma);
1200         mutex_unlock (&usblp->mut);
1201
1202         if (!usblp->used)
1203                 usblp_cleanup (usblp);
1204         mutex_unlock (&usblp_mutex);
1205 }
1206
1207 static int usblp_suspend (struct usb_interface *intf, pm_message_t message)
1208 {
1209         struct usblp *usblp = usb_get_intfdata (intf);
1210
1211         /* we take no more IO */
1212         usblp->sleeping = 1;
1213         usblp_unlink_urbs(usblp);
1214
1215         return 0;
1216 }
1217
1218 static int usblp_resume (struct usb_interface *intf)
1219 {
1220         struct usblp *usblp = usb_get_intfdata (intf);
1221         int r;
1222
1223         usblp->sleeping = 0;
1224         r = handle_bidir (usblp);
1225
1226         return r;
1227 }
1228
1229 static struct usb_device_id usblp_ids [] = {
1230         { USB_DEVICE_INFO(7, 1, 1) },
1231         { USB_DEVICE_INFO(7, 1, 2) },
1232         { USB_DEVICE_INFO(7, 1, 3) },
1233         { USB_INTERFACE_INFO(7, 1, 1) },
1234         { USB_INTERFACE_INFO(7, 1, 2) },
1235         { USB_INTERFACE_INFO(7, 1, 3) },
1236         { USB_DEVICE(0x04b8, 0x0202) }, /* Seiko Epson Receipt Printer M129C */
1237         { }                                             /* Terminating entry */
1238 };
1239
1240 MODULE_DEVICE_TABLE (usb, usblp_ids);
1241
1242 static struct usb_driver usblp_driver = {
1243         .name =         "usblp",
1244         .probe =        usblp_probe,
1245         .disconnect =   usblp_disconnect,
1246         .suspend =      usblp_suspend,
1247         .resume =       usblp_resume,
1248         .id_table =     usblp_ids,
1249         .supports_autosuspend = 1,
1250 };
1251
1252 static int __init usblp_init(void)
1253 {
1254         int retval;
1255         retval = usb_register(&usblp_driver);
1256         if (!retval)
1257                 info(DRIVER_VERSION ": " DRIVER_DESC);
1258
1259         return retval;
1260 }
1261
1262 static void __exit usblp_exit(void)
1263 {
1264         usb_deregister(&usblp_driver);
1265 }
1266
1267 module_init(usblp_init);
1268 module_exit(usblp_exit);
1269
1270 MODULE_AUTHOR( DRIVER_AUTHOR );
1271 MODULE_DESCRIPTION( DRIVER_DESC );
1272 module_param(proto_bias, int, S_IRUGO | S_IWUSR);
1273 MODULE_PARM_DESC(proto_bias, "Favourite protocol number");
1274 MODULE_LICENSE("GPL");