drivers/usb/class/usbtmc.c

   1 /**
   2  * drivers/usb/class/usbtmc.c - USB Test & Measurment class driver
   3  *
   4  * Copyright (C) 2007 Stefan Kopp, Gechingen, Germany
   5  * Copyright (C) 2008 Novell, Inc.
   6  * Copyright (C) 2008 Greg Kroah-Hartman <gregkh@suse.de>
   7  *
   8  * This program is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU General Public License
  10  * as published by the Free Software Foundation; either version 2
  11  * of the License, or (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * The GNU General Public License is available at
  19  * http://www.gnu.org/copyleft/gpl.html.
  20  */
  21
  22 #include <linux/init.h>
  23 #include <linux/module.h>
  24 #include <linux/fs.h>
  25 #include <linux/uaccess.h>
  26 #include <linux/kref.h>
  27 #include <linux/mutex.h>
  28 #include <linux/usb.h>
  29 #include <linux/usb/tmc.h>
  30
  31
  32 #define USBTMC_MINOR_BASE       176
  33
  34 /*
  35  * Size of driver internal IO buffer. Must be multiple of 4 and at least as
  36  * large as wMaxPacketSize (which is usually 512 bytes).
  37  */
  38 #define USBTMC_SIZE_IOBUFFER    2048
  39
  40 /* Default USB timeout (in milliseconds) */
  41 #define USBTMC_TIMEOUT          10
  42
  43 /*
  44  * Maximum number of read cycles to empty bulk in endpoint during CLEAR and
  45  * ABORT_BULK_IN requests. Ends the loop if (for whatever reason) a short
  46  * packet is never read.
  47  */
  48 #define USBTMC_MAX_READS_TO_CLEAR_BULK_IN       100
  49
  50 static struct usb_device_id usbtmc_devices[] = {
  51         { USB_INTERFACE_INFO(USB_CLASS_APP_SPEC, 3, 0), },
  52         { 0, } /* terminating entry */
  53 };
  54
  55 /*
  56  * This structure is the capabilities for the device
  57  * See section 4.2.1.8 of the USBTMC specification for details.
  58  */
  59 struct usbtmc_dev_capabilities {
  60         __u8 interface_capabilities;
  61         __u8 device_capabilities;
  62         __u8 usb488_interface_capabilities;
  63         __u8 usb488_device_capabilities;
  64 };
  65
  66 /* This structure holds private data for each USBTMC device. One copy is
  67  * allocated for each USBTMC device in the driver's probe function.
  68  */
  69 struct usbtmc_device_data {
  70         const struct usb_device_id *id;
  71         struct usb_device *usb_dev;
  72         struct usb_interface *intf;
  73
  74         unsigned int bulk_in;
  75         unsigned int bulk_out;
  76
  77         u8 bTag;
  78         u8 bTag_last_write;     /* needed for abort */
  79         u8 bTag_last_read;      /* needed for abort */
  80
  81         /* attributes from the USB TMC spec for this device */
  82         u8 TermChar;
  83         bool TermCharEnabled;
  84         bool auto_abort;
  85
  86         struct usbtmc_dev_capabilities  capabilities;
  87         struct kref kref;
  88         struct mutex io_mutex;  /* only one i/o function running at a time */
  89 };
  90 #define to_usbtmc_data(d) container_of(d, struct usbtmc_device_data, kref)
  91
  92 /* Forward declarations */
  93 static struct usb_driver usbtmc_driver;
  94
  95 static void usbtmc_delete(struct kref *kref)
  96 {
  97         struct usbtmc_device_data *data = to_usbtmc_data(kref);
  98
  99         usb_put_dev(data->usb_dev);
 100         kfree(data);
 101 }
 102
 103 static int usbtmc_open(struct inode *inode, struct file *filp)
 104 {
 105         struct usb_interface *intf;
 106         struct usbtmc_device_data *data;
 107         int retval = -ENODEV;
 108
 109         intf = usb_find_interface(&usbtmc_driver, iminor(inode));
 110         if (!intf) {
 111                 printk(KERN_ERR KBUILD_MODNAME
 112                        ": can not find device for minor %d", iminor(inode));
 113                 goto exit;
 114         }
 115
 116         data = usb_get_intfdata(intf);
 117         kref_get(&data->kref);
 118
 119         /* Store pointer in file structure's private data field */
 120         filp->private_data = data;
 121
 122 exit:
 123         return retval;
 124 }
 125
 126 static int usbtmc_release(struct inode *inode, struct file *file)
 127 {
 128         struct usbtmc_device_data *data = file->private_data;
 129
 130         kref_put(&data->kref, usbtmc_delete);
 131         return 0;
 132 }
 133
 134 static int usbtmc_ioctl_abort_bulk_in(struct usbtmc_device_data *data)
 135 {
 136         u8 *buffer;
 137         struct device *dev;
 138         int rv;
 139         int n;
 140         int actual;
 141         struct usb_host_interface *current_setting;
 142         int max_size;
 143
 144         dev = &data->intf->dev;
 145         buffer = kmalloc(USBTMC_SIZE_IOBUFFER, GFP_KERNEL);
 146         if (!buffer)
 147                 return -ENOMEM;
 148
 149         rv = usb_control_msg(data->usb_dev,
 150                              usb_rcvctrlpipe(data->usb_dev, 0),
 151                              USBTMC_REQUEST_INITIATE_ABORT_BULK_IN,
 152                              USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_ENDPOINT,
 153                              data->bTag_last_read, data->bulk_in,
 154                              buffer, 2, USBTMC_TIMEOUT);
 155
 156         if (rv < 0) {
 157                 dev_err(dev, "usb_control_msg returned %d\n", rv);
 158                 goto exit;
 159         }
 160
 161         dev_dbg(dev, "INITIATE_ABORT_BULK_IN returned %x\n", buffer[0]);
 162
 163         if (buffer[0] == USBTMC_STATUS_FAILED) {
 164                 rv = 0;
 165                 goto exit;
 166         }
 167
 168         if (buffer[0] != USBTMC_STATUS_SUCCESS) {
 169                 dev_err(dev, "INITIATE_ABORT_BULK_IN returned %x\n",
 170                         buffer[0]);
 171                 rv = -EPERM;
 172                 goto exit;
 173         }
 174
 175         max_size = 0;
 176         current_setting = data->intf->cur_altsetting;
 177         for (n = 0; n < current_setting->desc.bNumEndpoints; n++)
 178                 if (current_setting->endpoint[n].desc.bEndpointAddress ==
 179                         data->bulk_in)
 180                         max_size = le16_to_cpu(current_setting->endpoint[n].
 181                                                 desc.wMaxPacketSize);
 182
 183         if (max_size == 0) {
 184                 dev_err(dev, "Couldn't get wMaxPacketSize\n");
 185                 rv = -EPERM;
 186                 goto exit;
 187         }
 188
 189         dev_dbg(&data->intf->dev, "wMaxPacketSize is %d\n", max_size);
 190
 191         n = 0;
 192
 193         do {
 194                 dev_dbg(dev, "Reading from bulk in EP\n");
 195
 196                 rv = usb_bulk_msg(data->usb_dev,
 197                                   usb_rcvbulkpipe(data->usb_dev,
 198                                                   data->bulk_in),
 199                                   buffer, USBTMC_SIZE_IOBUFFER,
 200                                   &actual, USBTMC_TIMEOUT);
 201
 202                 n++;
 203
 204                 if (rv < 0) {
 205                         dev_err(dev, "usb_bulk_msg returned %d\n", rv);
 206                         goto exit;
 207                 }
 208         } while ((actual == max_size) &&
 209                  (n < USBTMC_MAX_READS_TO_CLEAR_BULK_IN));
 210
 211         if (actual == max_size) {
 212                 dev_err(dev, "Couldn't clear device buffer within %d cycles\n",
 213                         USBTMC_MAX_READS_TO_CLEAR_BULK_IN);
 214                 rv = -EPERM;
 215                 goto exit;
 216         }
 217
 218         n = 0;
 219
 220 usbtmc_abort_bulk_in_status:
 221         rv = usb_control_msg(data->usb_dev,
 222                              usb_rcvctrlpipe(data->usb_dev, 0),
 223                              USBTMC_REQUEST_CHECK_ABORT_BULK_IN_STATUS,
 224                              USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_ENDPOINT,
 225                              0, data->bulk_in, buffer, 0x08,
 226                              USBTMC_TIMEOUT);
 227
 228         if (rv < 0) {
 229                 dev_err(dev, "usb_control_msg returned %d\n", rv);
 230                 goto exit;
 231         }
 232
 233         dev_dbg(dev, "INITIATE_ABORT_BULK_IN returned %x\n", buffer[0]);
 234
 235         if (buffer[0] == USBTMC_STATUS_SUCCESS) {
 236                 rv = 0;
 237                 goto exit;
 238         }
 239
 240         if (buffer[0] != USBTMC_STATUS_PENDING) {
 241                 dev_err(dev, "INITIATE_ABORT_BULK_IN returned %x\n", buffer[0]);
 242                 rv = -EPERM;
 243                 goto exit;
 244         }
 245
 246         if (buffer[1] == 1)
 247                 do {
 248                         dev_dbg(dev, "Reading from bulk in EP\n");
 249
 250                         rv = usb_bulk_msg(data->usb_dev,
 251                                           usb_rcvbulkpipe(data->usb_dev,
 252                                                           data->bulk_in),
 253                                           buffer, USBTMC_SIZE_IOBUFFER,
 254                                           &actual, USBTMC_TIMEOUT);
 255
 256                         n++;
 257
 258                         if (rv < 0) {
 259                                 dev_err(dev, "usb_bulk_msg returned %d\n", rv);
 260                                 goto exit;
 261                         }
 262                 } while ((actual = max_size) &&
 263                          (n < USBTMC_MAX_READS_TO_CLEAR_BULK_IN));
 264
 265         if (actual == max_size) {
 266                 dev_err(dev, "Couldn't clear device buffer within %d cycles\n",
 267                         USBTMC_MAX_READS_TO_CLEAR_BULK_IN);
 268                 rv = -EPERM;
 269                 goto exit;
 270         }
 271
 272         goto usbtmc_abort_bulk_in_status;
 273
 274 exit:
 275         kfree(buffer);
 276         return rv;
 277
 278 }
 279
 280 static int usbtmc_ioctl_abort_bulk_out(struct usbtmc_device_data *data)
 281 {
 282         struct device *dev;
 283         u8 *buffer;
 284         int rv;
 285         int n;
 286
 287         dev = &data->intf->dev;
 288
 289         buffer = kmalloc(8, GFP_KERNEL);
 290         if (!buffer)
 291                 return -ENOMEM;
 292
 293         rv = usb_control_msg(data->usb_dev,
 294                              usb_rcvctrlpipe(data->usb_dev, 0),
 295                              USBTMC_REQUEST_INITIATE_ABORT_BULK_OUT,
 296                              USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_ENDPOINT,
 297                              data->bTag_last_write, data->bulk_out,
 298                              buffer, 2, USBTMC_TIMEOUT);
 299
 300         if (rv < 0) {
 301                 dev_err(dev, "usb_control_msg returned %d\n", rv);
 302                 goto exit;
 303         }
 304
 305         dev_dbg(dev, "INITIATE_ABORT_BULK_OUT returned %x\n", buffer[0]);
 306
 307         if (buffer[0] != USBTMC_STATUS_SUCCESS) {
 308                 dev_err(dev, "INITIATE_ABORT_BULK_OUT returned %x\n",
 309                         buffer[0]);
 310                 rv = -EPERM;
 311                 goto exit;
 312         }
 313
 314         n = 0;
 315
 316 usbtmc_abort_bulk_out_check_status:
 317         rv = usb_control_msg(data->usb_dev,
 318                              usb_rcvctrlpipe(data->usb_dev, 0),
 319                              USBTMC_REQUEST_CHECK_ABORT_BULK_OUT_STATUS,
 320                              USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_ENDPOINT,
 321                              0, data->bulk_out, buffer, 0x08,
 322                              USBTMC_TIMEOUT);
 323         n++;
 324         if (rv < 0) {
 325                 dev_err(dev, "usb_control_msg returned %d\n", rv);
 326                 goto exit;
 327         }
 328
 329         dev_dbg(dev, "CHECK_ABORT_BULK_OUT returned %x\n", buffer[0]);
 330
 331         if (buffer[0] == USBTMC_STATUS_SUCCESS)
 332                 goto usbtmc_abort_bulk_out_clear_halt;
 333
 334         if ((buffer[0] == USBTMC_STATUS_PENDING) &&
 335             (n < USBTMC_MAX_READS_TO_CLEAR_BULK_IN))
 336                 goto usbtmc_abort_bulk_out_check_status;
 337
 338         rv = -EPERM;
 339         goto exit;
 340
 341 usbtmc_abort_bulk_out_clear_halt:
 342         rv = usb_control_msg(data->usb_dev,
 343                              usb_sndctrlpipe(data->usb_dev, 0),
 344                              USB_REQ_CLEAR_FEATURE,
 345                              USB_DIR_OUT | USB_TYPE_STANDARD |
 346                              USB_RECIP_ENDPOINT,
 347                              USB_ENDPOINT_HALT, data->bulk_out, buffer,
 348                              0, USBTMC_TIMEOUT);
 349
 350         if (rv < 0) {
 351                 dev_err(dev, "usb_control_msg returned %d\n", rv);
 352                 goto exit;
 353         }
 354         rv = 0;
 355
 356 exit:
 357         kfree(buffer);
 358         return rv;
 359 }
 360
 361 static ssize_t usbtmc_read(struct file *filp, char __user *buf,
 362                            size_t count, loff_t *f_pos)
 363 {
 364         struct usbtmc_device_data *data;
 365         struct device *dev;
 366         unsigned long int n_characters;
 367         u8 *buffer;
 368         int actual;
 369         int done;
 370         int remaining;
 371         int retval;
 372         int this_part;
 373
 374         /* Get pointer to private data structure */
 375         data = filp->private_data;
 376         dev = &data->intf->dev;
 377
 378         buffer = kmalloc(USBTMC_SIZE_IOBUFFER, GFP_KERNEL);
 379         if (!buffer)
 380                 return -ENOMEM;
 381
 382         mutex_lock(&data->io_mutex);
 383
 384         remaining = count;
 385         done = 0;
 386
 387         while (remaining > 0) {
 388                 if (remaining > USBTMC_SIZE_IOBUFFER - 12 - 3)
 389                         this_part = USBTMC_SIZE_IOBUFFER - 12 - 3;
 390                 else
 391                         this_part = remaining;
 392
 393                 /* Setup IO buffer for DEV_DEP_MSG_IN message
 394                  * Refer to class specs for details
 395                  */
 396                 buffer[0] = 2;
 397                 buffer[1] = data->bTag;
 398                 buffer[2] = ~(data->bTag);
 399                 buffer[3] = 0; /* Reserved */
 400                 buffer[4] = (this_part - 12 - 3) & 255;
 401                 buffer[5] = ((this_part - 12 - 3) >> 8) & 255;
 402                 buffer[6] = ((this_part - 12 - 3) >> 16) & 255;
 403                 buffer[7] = ((this_part - 12 - 3) >> 24) & 255;
 404                 buffer[8] = data->TermCharEnabled * 2;
 405                 /* Use term character? */
 406                 buffer[9] = data->TermChar;
 407                 buffer[10] = 0; /* Reserved */
 408                 buffer[11] = 0; /* Reserved */
 409
 410                 /* Send bulk URB */
 411                 retval = usb_bulk_msg(data->usb_dev,
 412                                       usb_sndbulkpipe(data->usb_dev,
 413                                                       data->bulk_out),
 414                                       buffer, 12, &actual, USBTMC_TIMEOUT);
 415
 416                 /* Store bTag (in case we need to abort) */
 417                 data->bTag_last_write = data->bTag;
 418
 419                 /* Increment bTag -- and increment again if zero */
 420                 data->bTag++;
 421                 if (!data->bTag)
 422                         (data->bTag)++;
 423
 424                 if (retval < 0) {
 425                         dev_err(dev, "usb_bulk_msg returned %d\n", retval);
 426                         if (data->auto_abort)
 427                                 usbtmc_ioctl_abort_bulk_out(data);
 428                         goto exit;
 429                 }
 430
 431                 /* Send bulk URB */
 432                 retval = usb_bulk_msg(data->usb_dev,
 433                                       usb_rcvbulkpipe(data->usb_dev,
 434                                                       data->bulk_in),
 435                                       buffer, USBTMC_SIZE_IOBUFFER, &actual,
 436                                       USBTMC_TIMEOUT);
 437
 438                 /* Store bTag (in case we need to abort) */
 439                 data->bTag_last_read = data->bTag;
 440
 441                 if (retval < 0) {
 442                         dev_err(dev, "Unable to read data, error %d\n", retval);
 443                         if (data->auto_abort)
 444                                 usbtmc_ioctl_abort_bulk_in(data);
 445                         goto exit;
 446                 }
 447
 448                 /* How many characters did the instrument send? */
 449                 n_characters = buffer[4] +
 450                                (buffer[5] << 8) +
 451                                (buffer[6] << 16) +
 452                                (buffer[7] << 24);
 453
 454                 /* Copy buffer to user space */
 455                 if (copy_to_user(buf + done, &buffer[12], n_characters)) {
 456                         /* There must have been an addressing problem */
 457                         retval = -EFAULT;
 458                         goto exit;
 459                 }
 460
 461                 done += n_characters;
 462                 if (n_characters < USBTMC_SIZE_IOBUFFER)
 463                         remaining = 0;
 464         }
 465
 466         /* Update file position value */
 467         *f_pos = *f_pos + done;
 468         retval = done;
 469
 470 exit:
 471         mutex_unlock(&data->io_mutex);
 472         kfree(buffer);
 473         return retval;
 474 }
 475
 476 static ssize_t usbtmc_write(struct file *filp, const char __user *buf,
 477                             size_t count, loff_t *f_pos)
 478 {
 479         struct usbtmc_device_data *data;
 480         u8 *buffer;
 481         int retval;
 482         int actual;
 483         unsigned long int n_bytes;
 484         int n;
 485         int remaining;
 486         int done;
 487         int this_part;
 488
 489         data = filp->private_data;
 490
 491         buffer = kmalloc(USBTMC_SIZE_IOBUFFER, GFP_KERNEL);
 492         if (!buffer)
 493                 return -ENOMEM;
 494
 495         mutex_lock(&data->io_mutex);
 496
 497         remaining = count;
 498         done = 0;
 499
 500         while (remaining > 0) {
 501                 if (remaining > USBTMC_SIZE_IOBUFFER - 12) {
 502                         this_part = USBTMC_SIZE_IOBUFFER - 12;
 503                         buffer[8] = 0;
 504                 } else {
 505                         this_part = remaining;
 506                         buffer[8] = 1;
 507                 }
 508
 509                 /* Setup IO buffer for DEV_DEP_MSG_OUT message */
 510                 buffer[0] = 1;
 511                 buffer[1] = data->bTag;
 512                 buffer[2] = ~(data->bTag);
 513                 buffer[3] = 0; /* Reserved */
 514                 buffer[4] = this_part & 255;
 515                 buffer[5] = (this_part >> 8) & 255;
 516                 buffer[6] = (this_part >> 16) & 255;
 517                 buffer[7] = (this_part >> 24) & 255;
 518                 /* buffer[8] is set above... */
 519                 buffer[9] = 0; /* Reserved */
 520                 buffer[10] = 0; /* Reserved */
 521                 buffer[11] = 0; /* Reserved */
 522
 523                 if (copy_from_user(&buffer[12], buf + done, this_part)) {
 524                         retval = -EFAULT;
 525                         goto exit;
 526                 }
 527
 528                 n_bytes = 12 + this_part;
 529                 if (this_part % 4)
 530                         n_bytes += 4 - this_part % 4;
 531                         for (n = 12 + this_part; n < n_bytes; n++)
 532                                 buffer[n] = 0;
 533
 534                 retval = usb_bulk_msg(data->usb_dev,
 535                                       usb_sndbulkpipe(data->usb_dev,
 536                                                       data->bulk_out),
 537                                       buffer, n_bytes, &actual, USBTMC_TIMEOUT);
 538
 539                 data->bTag_last_write = data->bTag;
 540                 data->bTag++;
 541
 542                 if (!data->bTag)
 543                         data->bTag++;
 544
 545                 if (retval < 0) {
 546                         dev_err(&data->intf->dev,
 547                                 "Unable to send data, error %d\n", retval);
 548                         if (data->auto_abort)
 549                                 usbtmc_ioctl_abort_bulk_out(data);
 550                         goto exit;
 551                 }
 552
 553                 remaining -= this_part;
 554                 done += this_part;
 555         }
 556
 557         retval = count;
 558 exit:
 559         mutex_unlock(&data->io_mutex);
 560         kfree(buffer);
 561         return retval;
 562 }
 563
 564 static int usbtmc_ioctl_clear(struct usbtmc_device_data *data)
 565 {
 566         struct usb_host_interface *current_setting;
 567         struct usb_endpoint_descriptor *desc;
 568         struct device *dev;
 569         u8 *buffer;
 570         int rv;
 571         int n;
 572         int actual;
 573         int max_size;
 574
 575         dev = &data->intf->dev;
 576
 577         dev_dbg(dev, "Sending INITIATE_CLEAR request\n");
 578
 579         buffer = kmalloc(USBTMC_SIZE_IOBUFFER, GFP_KERNEL);
 580         if (!buffer)
 581                 return -ENOMEM;
 582
 583         rv = usb_control_msg(data->usb_dev,
 584                              usb_rcvctrlpipe(data->usb_dev, 0),
 585                              USBTMC_REQUEST_INITIATE_CLEAR,
 586                              USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE,
 587                              0, 0, buffer, 1, USBTMC_TIMEOUT);
 588         if (rv < 0) {
 589                 dev_err(dev, "usb_control_msg returned %d\n", rv);
 590                 goto exit;
 591         }
 592
 593         dev_dbg(dev, "INITIATE_CLEAR returned %x\n", buffer[0]);
 594
 595         if (buffer[0] != USBTMC_STATUS_SUCCESS) {
 596                 dev_err(dev, "INITIATE_CLEAR returned %x\n", buffer[0]);
 597                 rv = -EPERM;
 598                 goto exit;
 599         }
 600
 601         max_size = 0;
 602         current_setting = data->intf->cur_altsetting;
 603         for (n = 0; n < current_setting->desc.bNumEndpoints; n++) {
 604                 desc = &current_setting->endpoint[n].desc;
 605                 if (desc->bEndpointAddress == data->bulk_in)
 606                         max_size = le16_to_cpu(desc->wMaxPacketSize);
 607         }
 608
 609         if (max_size == 0) {
 610                 dev_err(dev, "Couldn't get wMaxPacketSize\n");
 611                 rv = -EPERM;
 612                 goto exit;
 613         }
 614
 615         dev_dbg(dev, "wMaxPacketSize is %d\n", max_size);
 616
 617         n = 0;
 618
 619 usbtmc_clear_check_status:
 620
 621         dev_dbg(dev, "Sending CHECK_CLEAR_STATUS request\n");
 622
 623         rv = usb_control_msg(data->usb_dev,
 624                              usb_rcvctrlpipe(data->usb_dev, 0),
 625                              USBTMC_REQUEST_CHECK_CLEAR_STATUS,
 626                              USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE,
 627                              0, 0, buffer, 2, USBTMC_TIMEOUT);
 628         if (rv < 0) {
 629                 dev_err(dev, "usb_control_msg returned %d\n", rv);
 630                 goto exit;
 631         }
 632
 633         dev_dbg(dev, "CHECK_CLEAR_STATUS returned %x\n", buffer[0]);
 634
 635         if (buffer[0] == USBTMC_STATUS_SUCCESS)
 636                 goto usbtmc_clear_bulk_out_halt;
 637
 638         if (buffer[0] != USBTMC_STATUS_PENDING) {
 639                 dev_err(dev, "CHECK_CLEAR_STATUS returned %x\n", buffer[0]);
 640                 rv = -EPERM;
 641                 goto exit;
 642         }
 643
 644         if (buffer[1] == 1)
 645                 do {
 646                         dev_dbg(dev, "Reading from bulk in EP\n");
 647
 648                         rv = usb_bulk_msg(data->usb_dev,
 649                                           usb_rcvbulkpipe(data->usb_dev,
 650                                                           data->bulk_in),
 651                                           buffer, USBTMC_SIZE_IOBUFFER,
 652                                           &actual, USBTMC_TIMEOUT);
 653                         n++;
 654
 655                         if (rv < 0) {
 656                                 dev_err(dev, "usb_control_msg returned %d\n",
 657                                         rv);
 658                                 goto exit;
 659                         }
 660                 } while ((actual == max_size) &&
 661                           (n < USBTMC_MAX_READS_TO_CLEAR_BULK_IN));
 662
 663         if (actual == max_size) {
 664                 dev_err(dev, "Couldn't clear device buffer within %d cycles\n",
 665                         USBTMC_MAX_READS_TO_CLEAR_BULK_IN);
 666                 rv = -EPERM;
 667                 goto exit;
 668         }
 669
 670         goto usbtmc_clear_check_status;
 671
 672 usbtmc_clear_bulk_out_halt:
 673
 674         rv = usb_control_msg(data->usb_dev,
 675                              usb_sndctrlpipe(data->usb_dev, 0),
 676                              USB_REQ_CLEAR_FEATURE,
 677                              USB_DIR_OUT | USB_TYPE_STANDARD |
 678                              USB_RECIP_ENDPOINT,
 679                              USB_ENDPOINT_HALT,
 680                              data->bulk_out, buffer, 0,
 681                              USBTMC_TIMEOUT);
 682         if (rv < 0) {
 683                 dev_err(dev, "usb_control_msg returned %d\n", rv);
 684                 goto exit;
 685         }
 686         rv = 0;
 687
 688 exit:
 689         kfree(buffer);
 690         return rv;
 691 }
 692
 693 static int usbtmc_ioctl_clear_out_halt(struct usbtmc_device_data *data)
 694 {
 695         u8 *buffer;
 696         int rv;
 697
 698         buffer = kmalloc(2, GFP_KERNEL);
 699         if (!buffer)
 700                 return -ENOMEM;
 701
 702         rv = usb_control_msg(data->usb_dev,
 703                              usb_sndctrlpipe(data->usb_dev, 0),
 704                              USB_REQ_CLEAR_FEATURE,
 705                              USB_DIR_OUT | USB_TYPE_STANDARD |
 706                              USB_RECIP_ENDPOINT,
 707                              USB_ENDPOINT_HALT, data->bulk_out,
 708                              buffer, 0, USBTMC_TIMEOUT);
 709
 710         if (rv < 0) {
 711                 dev_err(&data->usb_dev->dev, "usb_control_msg returned %d\n",
 712                         rv);
 713                 goto exit;
 714         }
 715         rv = 0;
 716
 717 exit:
 718         kfree(buffer);
 719         return rv;
 720 }
 721
 722 static int usbtmc_ioctl_clear_in_halt(struct usbtmc_device_data *data)
 723 {
 724         u8 *buffer;
 725         int rv;
 726
 727         buffer = kmalloc(2, GFP_KERNEL);
 728         if (!buffer)
 729                 return -ENOMEM;
 730
 731         rv = usb_control_msg(data->usb_dev, usb_sndctrlpipe(data->usb_dev, 0),
 732                              USB_REQ_CLEAR_FEATURE,
 733                              USB_DIR_OUT | USB_TYPE_STANDARD |
 734                              USB_RECIP_ENDPOINT,
 735                              USB_ENDPOINT_HALT, data->bulk_in, buffer, 0,
 736                              USBTMC_TIMEOUT);
 737
 738         if (rv < 0) {
 739                 dev_err(&data->usb_dev->dev, "usb_control_msg returned %d\n",
 740                         rv);
 741                 goto exit;
 742         }
 743         rv = 0;
 744
 745 exit:
 746         kfree(buffer);
 747         return rv;
 748 }
 749
 750 static int get_capabilities(struct usbtmc_device_data *data)
 751 {
 752         struct device *dev = &data->usb_dev->dev;
 753         char *buffer;
 754         int rv;
 755
 756         buffer = kmalloc(0x18, GFP_KERNEL);
 757         if (!buffer)
 758                 return -ENOMEM;
 759
 760         rv = usb_control_msg(data->usb_dev, usb_rcvctrlpipe(data->usb_dev, 0),
 761                              USBTMC_REQUEST_GET_CAPABILITIES,
 762                              USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE,
 763                              0, 0, buffer, 0x18, USBTMC_TIMEOUT);
 764         if (rv < 0) {
 765                 dev_err(dev, "usb_control_msg returned %d\n", rv);
 766                 return rv;
 767         }
 768
 769         dev_dbg(dev, "GET_CAPABILITIES returned %x\n", buffer[0]);
 770         dev_dbg(dev, "Interface capabilities are %x\n", buffer[4]);
 771         dev_dbg(dev, "Device capabilities are %x\n", buffer[5]);
 772         dev_dbg(dev, "USB488 interface capabilities are %x\n", buffer[14]);
 773         dev_dbg(dev, "USB488 device capabilities are %x\n", buffer[15]);
 774         if (buffer[0] != USBTMC_STATUS_SUCCESS) {
 775                 dev_err(dev, "GET_CAPABILITIES returned %x\n", buffer[0]);
 776                 return -EPERM;
 777         }
 778
 779         data->capabilities.interface_capabilities = buffer[4];
 780         data->capabilities.device_capabilities = buffer[5];
 781         data->capabilities.usb488_interface_capabilities = buffer[14];
 782         data->capabilities.usb488_device_capabilities = buffer[15];
 783
 784         kfree(buffer);
 785         return 0;
 786 }
 787
 788 #define capability_attribute(name)                                      \
 789 static ssize_t show_##name(struct device *dev,                          \
 790                            struct device_attribute *attr, char *buf)    \
 791 {                                                                       \
 792         struct usb_interface *intf = to_usb_interface(dev);             \
 793         struct usbtmc_device_data *data = usb_get_intfdata(intf);       \
 794                                                                         \
 795         return sprintf(buf, "%d\n", data->capabilities.name);           \
 796 }                                                                       \
 797 static DEVICE_ATTR(name, S_IRUGO, show_##name, NULL)
 798
 799 capability_attribute(interface_capabilities);
 800 capability_attribute(device_capabilities);
 801 capability_attribute(usb488_interface_capabilities);
 802 capability_attribute(usb488_device_capabilities);
 803
 804 static struct attribute *capability_attrs[] = {
 805         &dev_attr_interface_capabilities.attr,
 806         &dev_attr_device_capabilities.attr,
 807         &dev_attr_usb488_interface_capabilities.attr,
 808         &dev_attr_usb488_device_capabilities.attr,
 809         NULL,
 810 };
 811
 812 static struct attribute_group capability_attr_grp = {
 813         .attrs = capability_attrs,
 814 };
 815
 816 static ssize_t show_TermChar(struct device *dev,
 817                              struct device_attribute *attr, char *buf)
 818 {
 819         struct usb_interface *intf = to_usb_interface(dev);
 820         struct usbtmc_device_data *data = usb_get_intfdata(intf);
 821
 822         return sprintf(buf, "%c\n", data->TermChar);
 823 }
 824
 825 static ssize_t store_TermChar(struct device *dev,
 826                               struct device_attribute *attr,
 827                               const char *buf, size_t count)
 828 {
 829         struct usb_interface *intf = to_usb_interface(dev);
 830         struct usbtmc_device_data *data = usb_get_intfdata(intf);
 831
 832         if (count < 1)
 833                 return -EINVAL;
 834         data->TermChar = buf[0];
 835         return count;
 836 }
 837 static DEVICE_ATTR(TermChar, S_IRUGO, show_TermChar, store_TermChar);
 838
 839 #define data_attribute(name)                                            \
 840 static ssize_t show_##name(struct device *dev,                          \
 841                            struct device_attribute *attr, char *buf)    \
 842 {                                                                       \
 843         struct usb_interface *intf = to_usb_interface(dev);             \
 844         struct usbtmc_device_data *data = usb_get_intfdata(intf);       \
 845                                                                         \
 846         return sprintf(buf, "%d\n", data->name);                        \
 847 }                                                                       \
 848 static ssize_t store_##name(struct device *dev,                         \
 849                             struct device_attribute *attr,              \
 850                             const char *buf, size_t count)              \
 851 {                                                                       \
 852         struct usb_interface *intf = to_usb_interface(dev);             \
 853         struct usbtmc_device_data *data = usb_get_intfdata(intf);       \
 854         ssize_t result;                                                 \
 855         unsigned val;                                                   \
 856                                                                         \
 857         result = sscanf(buf, "%u\n", &val);                             \
 858         if (result != 1)                                                \
 859                 result = -EINVAL;                                       \
 860         data->name = val;                                               \
 861         if (result < 0)                                                 \
 862                 return result;                                          \
 863         else                                                            \
 864                 return count;                                           \
 865 }                                                                       \
 866 static DEVICE_ATTR(name, S_IRUGO, show_##name, store_##name)
 867
 868 data_attribute(TermCharEnabled);
 869 data_attribute(auto_abort);
 870
 871 static struct attribute *data_attrs[] = {
 872         &dev_attr_TermChar.attr,
 873         &dev_attr_TermCharEnabled.attr,
 874         &dev_attr_auto_abort.attr,
 875         NULL,
 876 };
 877
 878 static struct attribute_group data_attr_grp = {
 879         .attrs = data_attrs,
 880 };
 881
 882 static int usbtmc_ioctl_indicator_pulse(struct usbtmc_device_data *data)
 883 {
 884         struct device *dev;
 885         u8 *buffer;
 886         int rv;
 887
 888         dev = &data->intf->dev;
 889
 890         buffer = kmalloc(2, GFP_KERNEL);
 891         if (!buffer)
 892                 return -ENOMEM;
 893
 894         rv = usb_control_msg(data->usb_dev,
 895                              usb_rcvctrlpipe(data->usb_dev, 0),
 896                              USBTMC_REQUEST_INDICATOR_PULSE,
 897                              USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE,
 898                              0, 0, buffer, 0x01, USBTMC_TIMEOUT);
 899
 900         if (rv < 0) {
 901                 dev_err(dev, "usb_control_msg returned %d\n", rv);
 902                 goto exit;
 903         }
 904
 905         dev_dbg(dev, "INDICATOR_PULSE returned %x\n", buffer[0]);
 906
 907         if (buffer[0] != USBTMC_STATUS_SUCCESS) {
 908                 dev_err(dev, "INDICATOR_PULSE returned %x\n", buffer[0]);
 909                 rv = -EPERM;
 910                 goto exit;
 911         }
 912         rv = 0;
 913
 914 exit:
 915         kfree(buffer);
 916         return rv;
 917 }
 918
 919 static long usbtmc_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 920 {
 921         struct usbtmc_device_data *data;
 922         int retval = -EBADRQC;
 923
 924         data = file->private_data;
 925         mutex_lock(&data->io_mutex);
 926
 927         switch (cmd) {
 928         case USBTMC_IOCTL_CLEAR_OUT_HALT:
 929                 retval = usbtmc_ioctl_clear_out_halt(data);
 930
 931         case USBTMC_IOCTL_CLEAR_IN_HALT:
 932                 retval = usbtmc_ioctl_clear_in_halt(data);
 933
 934         case USBTMC_IOCTL_INDICATOR_PULSE:
 935                 retval = usbtmc_ioctl_indicator_pulse(data);
 936
 937         case USBTMC_IOCTL_CLEAR:
 938                 retval = usbtmc_ioctl_clear(data);
 939
 940         case USBTMC_IOCTL_ABORT_BULK_OUT:
 941                 retval = usbtmc_ioctl_abort_bulk_out(data);
 942
 943         case USBTMC_IOCTL_ABORT_BULK_IN:
 944                 retval = usbtmc_ioctl_abort_bulk_in(data);
 945         }
 946
 947         mutex_unlock(&data->io_mutex);
 948         return retval;
 949 }
 950
 951 static struct file_operations fops = {
 952         .owner          = THIS_MODULE,
 953         .read           = usbtmc_read,
 954         .write          = usbtmc_write,
 955         .open           = usbtmc_open,
 956         .release        = usbtmc_release,
 957         .unlocked_ioctl = usbtmc_ioctl,
 958 };
 959
 960 static struct usb_class_driver usbtmc_class = {
 961         .name =         "usbtmc%d",
 962         .fops =         &fops,
 963         .minor_base =   USBTMC_MINOR_BASE,
 964 };
 965
 966
 967 static int usbtmc_probe(struct usb_interface *intf,
 968                         const struct usb_device_id *id)
 969 {
 970         struct usbtmc_device_data *data;
 971         struct usb_host_interface *iface_desc;
 972         struct usb_endpoint_descriptor *endpoint;
 973         int n;
 974         int retcode;
 975
 976         dev_dbg(&intf->dev, "%s called\n", __func__);
 977
 978         data = kmalloc(sizeof(struct usbtmc_device_data), GFP_KERNEL);
 979         if (!data) {
 980                 dev_err(&intf->dev, "Unable to allocate kernel memory\n");
 981                 return -ENOMEM;
 982         }
 983
 984         data->intf = intf;
 985         data->id = id;
 986         data->usb_dev = usb_get_dev(interface_to_usbdev(intf));
 987         usb_set_intfdata(intf, data);
 988         kref_init(&data->kref);
 989         mutex_init(&data->io_mutex);
 990
 991         /* Initialize USBTMC bTag and other fields */
 992         data->bTag      = 1;
 993         data->TermCharEnabled = 0;
 994         data->TermChar = '\n';
 995
 996         /* USBTMC devices have only one setting, so use that */
 997         iface_desc = data->intf->cur_altsetting;
 998
 999         /* Find bulk in endpoint */
1000         for (n = 0; n < iface_desc->desc.bNumEndpoints; n++) {
1001                 endpoint = &iface_desc->endpoint[n].desc;
1002
1003                 if (usb_endpoint_is_bulk_in(endpoint)) {
1004                         data->bulk_in = endpoint->bEndpointAddress;
1005                         dev_dbg(&intf->dev, "Found bulk in endpoint at %u\n",
1006                                 data->bulk_in);
1007                         break;
1008                 }
1009         }
1010
1011         /* Find bulk out endpoint */
1012         for (n = 0; n < iface_desc->desc.bNumEndpoints; n++) {
1013                 endpoint = &iface_desc->endpoint[n].desc;
1014
1015                 if (usb_endpoint_is_bulk_out(endpoint)) {
1016                         data->bulk_out = endpoint->bEndpointAddress;
1017                         dev_dbg(&intf->dev, "Found Bulk out endpoint at %u\n",
1018                                 data->bulk_out);
1019                         break;
1020                 }
1021         }
1022
1023         retcode = get_capabilities(data);
1024         if (retcode)
1025                 dev_err(&intf->dev, "can't read capabilities\n");
1026         else
1027                 retcode = sysfs_create_group(&intf->dev.kobj,
1028                                              &capability_attr_grp);
1029
1030         retcode = sysfs_create_group(&intf->dev.kobj, &data_attr_grp);
1031
1032         retcode = usb_register_dev(intf, &usbtmc_class);
1033         if (retcode) {
1034                 dev_err(&intf->dev, "Not able to get a minor"
1035                         " (base %u, slice default): %d\n", USBTMC_MINOR_BASE,
1036                         retcode);
1037                 goto error_register;
1038         }
1039         dev_dbg(&intf->dev, "Using minor number %d\n", intf->minor);
1040
1041         return 0;
1042
1043 error_register:
1044         sysfs_remove_group(&intf->dev.kobj, &capability_attr_grp);
1045         sysfs_remove_group(&intf->dev.kobj, &data_attr_grp);
1046         kref_put(&data->kref, usbtmc_delete);
1047         return retcode;
1048 }
1049
1050 static void usbtmc_disconnect(struct usb_interface *intf)
1051 {
1052         struct usbtmc_device_data *data;
1053
1054         dev_dbg(&intf->dev, "usbtmc_disconnect called\n");
1055
1056         data = usb_get_intfdata(intf);
1057         usb_deregister_dev(intf, &usbtmc_class);
1058         sysfs_remove_group(&intf->dev.kobj, &capability_attr_grp);
1059         sysfs_remove_group(&intf->dev.kobj, &data_attr_grp);
1060         kref_put(&data->kref, usbtmc_delete);
1061 }
1062
1063 static struct usb_driver usbtmc_driver = {
1064         .name           = "usbtmc",
1065         .id_table       = usbtmc_devices,
1066         .probe          = usbtmc_probe,
1067         .disconnect     = usbtmc_disconnect
1068 };
1069
1070 static int __init usbtmc_init(void)
1071 {
1072         int retcode;
1073
1074         retcode = usb_register(&usbtmc_driver);
1075         if (retcode)
1076                 printk(KERN_ERR KBUILD_MODNAME": Unable to register driver\n");
1077         return retcode;
1078 }
1079 module_init(usbtmc_init);
1080
1081 static void __exit usbtmc_exit(void)
1082 {
1083         usb_deregister(&usbtmc_driver);
1084 }
1085 module_exit(usbtmc_exit);
1086
1087 MODULE_LICENSE("GPL");