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