drivers/usb/class/usbtmc.c

   1 /**
   2  * drivers/usb/class/usbtmc.c - USB Test & Measurement 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          5000
  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         { USB_INTERFACE_INFO(USB_CLASS_APP_SPEC, 3, 1), },
  54         { 0, } /* terminating entry */
  55 };
  56 MODULE_DEVICE_TABLE(usb, usbtmc_devices);
  57
  58 /*
  59  * This structure is the capabilities for the device
  60  * See section 4.2.1.8 of the USBTMC specification,
  61  * and section 4.2.2 of the USBTMC usb488 subclass
  62  * specification for details.
  63  */
  64 struct usbtmc_dev_capabilities {
  65         __u8 interface_capabilities;
  66         __u8 device_capabilities;
  67         __u8 usb488_interface_capabilities;
  68         __u8 usb488_device_capabilities;
  69 };
  70
  71 /* This structure holds private data for each USBTMC device. One copy is
  72  * allocated for each USBTMC device in the driver's probe function.
  73  */
  74 struct usbtmc_device_data {
  75         const struct usb_device_id *id;
  76         struct usb_device *usb_dev;
  77         struct usb_interface *intf;
  78
  79         unsigned int bulk_in;
  80         unsigned int bulk_out;
  81
  82         u8 bTag;
  83         u8 bTag_last_write;     /* needed for abort */
  84         u8 bTag_last_read;      /* needed for abort */
  85
  86         /* attributes from the USB TMC spec for this device */
  87         u8 TermChar;
  88         bool TermCharEnabled;
  89         bool auto_abort;
  90
  91         bool zombie; /* fd of disconnected device */
  92
  93         struct usbtmc_dev_capabilities  capabilities;
  94         struct kref kref;
  95         struct mutex io_mutex;  /* only one i/o function running at a time */
  96 };
  97 #define to_usbtmc_data(d) container_of(d, struct usbtmc_device_data, kref)
  98
  99 /* Forward declarations */
 100 static struct usb_driver usbtmc_driver;
 101
 102 static void usbtmc_delete(struct kref *kref)
 103 {
 104         struct usbtmc_device_data *data = to_usbtmc_data(kref);
 105
 106         usb_put_dev(data->usb_dev);
 107         kfree(data);
 108 }
 109
 110 static int usbtmc_open(struct inode *inode, struct file *filp)
 111 {
 112         struct usb_interface *intf;
 113         struct usbtmc_device_data *data;
 114         int retval = 0;
 115
 116         intf = usb_find_interface(&usbtmc_driver, iminor(inode));
 117         if (!intf) {
 118                 printk(KERN_ERR KBUILD_MODNAME
 119                        ": can not find device for minor %d", iminor(inode));
 120                 retval = -ENODEV;
 121                 goto exit;
 122         }
 123
 124         data = usb_get_intfdata(intf);
 125         kref_get(&data->kref);
 126
 127         /* Store pointer in file structure's private data field */
 128         filp->private_data = data;
 129
 130 exit:
 131         return retval;
 132 }
 133
 134 static int usbtmc_release(struct inode *inode, struct file *file)
 135 {
 136         struct usbtmc_device_data *data = file->private_data;
 137
 138         kref_put(&data->kref, usbtmc_delete);
 139         return 0;
 140 }
 141
 142 static int usbtmc_ioctl_abort_bulk_in(struct usbtmc_device_data *data)
 143 {
 144         u8 *buffer;
 145         struct device *dev;
 146         int rv;
 147         int n;
 148         int actual;
 149         struct usb_host_interface *current_setting;
 150         int max_size;
 151
 152         dev = &data->intf->dev;
 153         buffer = kmalloc(USBTMC_SIZE_IOBUFFER, GFP_KERNEL);
 154         if (!buffer)
 155                 return -ENOMEM;
 156
 157         rv = usb_control_msg(data->usb_dev,
 158                              usb_rcvctrlpipe(data->usb_dev, 0),
 159                              USBTMC_REQUEST_INITIATE_ABORT_BULK_IN,
 160                              USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_ENDPOINT,
 161                              data->bTag_last_read, data->bulk_in,
 162                              buffer, 2, USBTMC_TIMEOUT);
 163
 164         if (rv < 0) {
 165                 dev_err(dev, "usb_control_msg returned %d\n", rv);
 166                 goto exit;
 167         }
 168
 169         dev_dbg(dev, "INITIATE_ABORT_BULK_IN returned %x\n", buffer[0]);
 170
 171         if (buffer[0] == USBTMC_STATUS_FAILED) {
 172                 rv = 0;
 173                 goto exit;
 174         }
 175
 176         if (buffer[0] != USBTMC_STATUS_SUCCESS) {
 177                 dev_err(dev, "INITIATE_ABORT_BULK_IN returned %x\n",
 178                         buffer[0]);
 179                 rv = -EPERM;
 180                 goto exit;
 181         }
 182
 183         max_size = 0;
 184         current_setting = data->intf->cur_altsetting;
 185         for (n = 0; n < current_setting->desc.bNumEndpoints; n++)
 186                 if (current_setting->endpoint[n].desc.bEndpointAddress ==
 187                         data->bulk_in)
 188                         max_size = le16_to_cpu(current_setting->endpoint[n].
 189                                                 desc.wMaxPacketSize);
 190
 191         if (max_size == 0) {
 192                 dev_err(dev, "Couldn't get wMaxPacketSize\n");
 193                 rv = -EPERM;
 194                 goto exit;
 195         }
 196
 197         dev_dbg(&data->intf->dev, "wMaxPacketSize is %d\n", max_size);
 198
 199         n = 0;
 200
 201         do {
 202                 dev_dbg(dev, "Reading from bulk in EP\n");
 203
 204                 rv = usb_bulk_msg(data->usb_dev,
 205                                   usb_rcvbulkpipe(data->usb_dev,
 206                                                   data->bulk_in),
 207                                   buffer, USBTMC_SIZE_IOBUFFER,
 208                                   &actual, USBTMC_TIMEOUT);
 209
 210                 n++;
 211
 212                 if (rv < 0) {
 213                         dev_err(dev, "usb_bulk_msg returned %d\n", rv);
 214                         goto exit;
 215                 }
 216         } while ((actual == max_size) &&
 217                  (n < USBTMC_MAX_READS_TO_CLEAR_BULK_IN));
 218
 219         if (actual == max_size) {
 220                 dev_err(dev, "Couldn't clear device buffer within %d cycles\n",
 221                         USBTMC_MAX_READS_TO_CLEAR_BULK_IN);
 222                 rv = -EPERM;
 223                 goto exit;
 224         }
 225
 226         n = 0;
 227
 228 usbtmc_abort_bulk_in_status:
 229         rv = usb_control_msg(data->usb_dev,
 230                              usb_rcvctrlpipe(data->usb_dev, 0),
 231                              USBTMC_REQUEST_CHECK_ABORT_BULK_IN_STATUS,
 232                              USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_ENDPOINT,
 233                              0, data->bulk_in, buffer, 0x08,
 234                              USBTMC_TIMEOUT);
 235
 236         if (rv < 0) {
 237                 dev_err(dev, "usb_control_msg returned %d\n", rv);
 238                 goto exit;
 239         }
 240
 241         dev_dbg(dev, "INITIATE_ABORT_BULK_IN returned %x\n", buffer[0]);
 242
 243         if (buffer[0] == USBTMC_STATUS_SUCCESS) {
 244                 rv = 0;
 245                 goto exit;
 246         }
 247
 248         if (buffer[0] != USBTMC_STATUS_PENDING) {
 249                 dev_err(dev, "INITIATE_ABORT_BULK_IN returned %x\n", buffer[0]);
 250                 rv = -EPERM;
 251                 goto exit;
 252         }
 253
 254         if (buffer[1] == 1)
 255                 do {
 256                         dev_dbg(dev, "Reading from bulk in EP\n");
 257
 258                         rv = usb_bulk_msg(data->usb_dev,
 259                                           usb_rcvbulkpipe(data->usb_dev,
 260                                                           data->bulk_in),
 261                                           buffer, USBTMC_SIZE_IOBUFFER,
 262                                           &actual, USBTMC_TIMEOUT);
 263
 264                         n++;
 265
 266                         if (rv < 0) {
 267                                 dev_err(dev, "usb_bulk_msg returned %d\n", rv);
 268                                 goto exit;
 269                         }
 270                 } while ((actual = max_size) &&
 271                          (n < USBTMC_MAX_READS_TO_CLEAR_BULK_IN));
 272
 273         if (actual == max_size) {
 274                 dev_err(dev, "Couldn't clear device buffer within %d cycles\n",
 275                         USBTMC_MAX_READS_TO_CLEAR_BULK_IN);
 276                 rv = -EPERM;
 277                 goto exit;
 278         }
 279
 280         goto usbtmc_abort_bulk_in_status;
 281
 282 exit:
 283         kfree(buffer);
 284         return rv;
 285
 286 }
 287
 288 static int usbtmc_ioctl_abort_bulk_out(struct usbtmc_device_data *data)
 289 {
 290         struct device *dev;
 291         u8 *buffer;
 292         int rv;
 293         int n;
 294
 295         dev = &data->intf->dev;
 296
 297         buffer = kmalloc(8, GFP_KERNEL);
 298         if (!buffer)
 299                 return -ENOMEM;
 300
 301         rv = usb_control_msg(data->usb_dev,
 302                              usb_rcvctrlpipe(data->usb_dev, 0),
 303                              USBTMC_REQUEST_INITIATE_ABORT_BULK_OUT,
 304                              USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_ENDPOINT,
 305                              data->bTag_last_write, data->bulk_out,
 306                              buffer, 2, USBTMC_TIMEOUT);
 307
 308         if (rv < 0) {
 309                 dev_err(dev, "usb_control_msg returned %d\n", rv);
 310                 goto exit;
 311         }
 312
 313         dev_dbg(dev, "INITIATE_ABORT_BULK_OUT returned %x\n", buffer[0]);
 314
 315         if (buffer[0] != USBTMC_STATUS_SUCCESS) {
 316                 dev_err(dev, "INITIATE_ABORT_BULK_OUT returned %x\n",
 317                         buffer[0]);
 318                 rv = -EPERM;
 319                 goto exit;
 320         }
 321
 322         n = 0;
 323
 324 usbtmc_abort_bulk_out_check_status:
 325         rv = usb_control_msg(data->usb_dev,
 326                              usb_rcvctrlpipe(data->usb_dev, 0),
 327                              USBTMC_REQUEST_CHECK_ABORT_BULK_OUT_STATUS,
 328                              USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_ENDPOINT,
 329                              0, data->bulk_out, buffer, 0x08,
 330                              USBTMC_TIMEOUT);
 331         n++;
 332         if (rv < 0) {
 333                 dev_err(dev, "usb_control_msg returned %d\n", rv);
 334                 goto exit;
 335         }
 336
 337         dev_dbg(dev, "CHECK_ABORT_BULK_OUT returned %x\n", buffer[0]);
 338
 339         if (buffer[0] == USBTMC_STATUS_SUCCESS)
 340                 goto usbtmc_abort_bulk_out_clear_halt;
 341
 342         if ((buffer[0] == USBTMC_STATUS_PENDING) &&
 343             (n < USBTMC_MAX_READS_TO_CLEAR_BULK_IN))
 344                 goto usbtmc_abort_bulk_out_check_status;
 345
 346         rv = -EPERM;
 347         goto exit;
 348
 349 usbtmc_abort_bulk_out_clear_halt:
 350         rv = usb_control_msg(data->usb_dev,
 351                              usb_sndctrlpipe(data->usb_dev, 0),
 352                              USB_REQ_CLEAR_FEATURE,
 353                              USB_DIR_OUT | USB_TYPE_STANDARD |
 354                              USB_RECIP_ENDPOINT,
 355                              USB_ENDPOINT_HALT, data->bulk_out, buffer,
 356                              0, USBTMC_TIMEOUT);
 357
 358         if (rv < 0) {
 359                 dev_err(dev, "usb_control_msg returned %d\n", rv);
 360                 goto exit;
 361         }
 362         rv = 0;
 363
 364 exit:
 365         kfree(buffer);
 366         return rv;
 367 }
 368
 369 static ssize_t usbtmc_read(struct file *filp, char __user *buf,
 370                            size_t count, loff_t *f_pos)
 371 {
 372         struct usbtmc_device_data *data;
 373         struct device *dev;
 374         u32 n_characters;
 375         u8 *buffer;
 376         int actual;
 377         size_t done;
 378         size_t remaining;
 379         int retval;
 380         size_t this_part;
 381
 382         /* Get pointer to private data structure */
 383         data = filp->private_data;
 384         dev = &data->intf->dev;
 385
 386         buffer = kmalloc(USBTMC_SIZE_IOBUFFER, GFP_KERNEL);
 387         if (!buffer)
 388                 return -ENOMEM;
 389
 390         mutex_lock(&data->io_mutex);
 391         if (data->zombie) {
 392                 retval = -ENODEV;
 393                 goto exit;
 394         }
 395
 396         remaining = count;
 397         done = 0;
 398
 399         while (remaining > 0) {
 400                 if (remaining > USBTMC_SIZE_IOBUFFER - 12 - 3)
 401                         this_part = USBTMC_SIZE_IOBUFFER - 12 - 3;
 402                 else
 403                         this_part = remaining;
 404
 405                 /* Setup IO buffer for DEV_DEP_MSG_IN message
 406                  * Refer to class specs for details
 407                  */
 408                 buffer[0] = 2;
 409                 buffer[1] = data->bTag;
 410                 buffer[2] = ~(data->bTag);
 411                 buffer[3] = 0; /* Reserved */
 412                 buffer[4] = (this_part) & 255;
 413                 buffer[5] = ((this_part) >> 8) & 255;
 414                 buffer[6] = ((this_part) >> 16) & 255;
 415                 buffer[7] = ((this_part) >> 24) & 255;
 416                 buffer[8] = data->TermCharEnabled * 2;
 417                 /* Use term character? */
 418                 buffer[9] = data->TermChar;
 419                 buffer[10] = 0; /* Reserved */
 420                 buffer[11] = 0; /* Reserved */
 421
 422                 /* Send bulk URB */
 423                 retval = usb_bulk_msg(data->usb_dev,
 424                                       usb_sndbulkpipe(data->usb_dev,
 425                                                       data->bulk_out),
 426                                       buffer, 12, &actual, USBTMC_TIMEOUT);
 427
 428                 /* Store bTag (in case we need to abort) */
 429                 data->bTag_last_write = data->bTag;
 430
 431                 /* Increment bTag -- and increment again if zero */
 432                 data->bTag++;
 433                 if (!data->bTag)
 434                         (data->bTag)++;
 435
 436                 if (retval < 0) {
 437                         dev_err(dev, "usb_bulk_msg returned %d\n", retval);
 438                         if (data->auto_abort)
 439                                 usbtmc_ioctl_abort_bulk_out(data);
 440                         goto exit;
 441                 }
 442
 443                 /* Send bulk URB */
 444                 retval = usb_bulk_msg(data->usb_dev,
 445                                       usb_rcvbulkpipe(data->usb_dev,
 446                                                       data->bulk_in),
 447                                       buffer, USBTMC_SIZE_IOBUFFER, &actual,
 448                                       USBTMC_TIMEOUT);
 449
 450                 /* Store bTag (in case we need to abort) */
 451                 data->bTag_last_read = data->bTag;
 452
 453                 if (retval < 0) {
 454                         dev_err(dev, "Unable to read data, error %d\n", retval);
 455                         if (data->auto_abort)
 456                                 usbtmc_ioctl_abort_bulk_in(data);
 457                         goto exit;
 458                 }
 459
 460                 /* How many characters did the instrument send? */
 461                 n_characters = buffer[4] +
 462                                (buffer[5] << 8) +
 463                                (buffer[6] << 16) +
 464                                (buffer[7] << 24);
 465
 466                 /* Ensure the instrument doesn't lie about it */
 467                 if(n_characters > actual - 12) {
 468                         dev_err(dev, "Device lies about message size: %u > %d\n", n_characters, actual - 12);
 469                         n_characters = actual - 12;
 470                 }
 471
 472                 /* Ensure the instrument doesn't send more back than requested */
 473                 if(n_characters > this_part) {
 474                         dev_err(dev, "Device returns more than requested: %zu > %zu\n", done + n_characters, done + this_part);
 475                         n_characters = this_part;
 476                 }
 477
 478                 /* Bound amount of data received by amount of data requested */
 479                 if (n_characters > this_part)
 480                         n_characters = this_part;
 481
 482                 /* Copy buffer to user space */
 483                 if (copy_to_user(buf + done, &buffer[12], n_characters)) {
 484                         /* There must have been an addressing problem */
 485                         retval = -EFAULT;
 486                         goto exit;
 487                 }
 488
 489                 done += n_characters;
 490                 /* Terminate if end-of-message bit recieved from device */
 491                 if ((buffer[8] &  0x01) && (actual >= n_characters + 12))
 492                         remaining = 0;
 493                 else
 494                         remaining -= n_characters;
 495         }
 496
 497         /* Update file position value */
 498         *f_pos = *f_pos + done;
 499         retval = done;
 500
 501 exit:
 502         mutex_unlock(&data->io_mutex);
 503         kfree(buffer);
 504         return retval;
 505 }
 506
 507 static ssize_t usbtmc_write(struct file *filp, const char __user *buf,
 508                             size_t count, loff_t *f_pos)
 509 {
 510         struct usbtmc_device_data *data;
 511         u8 *buffer;
 512         int retval;
 513         int actual;
 514         unsigned long int n_bytes;
 515         int remaining;
 516         int done;
 517         int this_part;
 518
 519         data = filp->private_data;
 520
 521         buffer = kmalloc(USBTMC_SIZE_IOBUFFER, GFP_KERNEL);
 522         if (!buffer)
 523                 return -ENOMEM;
 524
 525         mutex_lock(&data->io_mutex);
 526         if (data->zombie) {
 527                 retval = -ENODEV;
 528                 goto exit;
 529         }
 530
 531         remaining = count;
 532         done = 0;
 533
 534         while (remaining > 0) {
 535                 if (remaining > USBTMC_SIZE_IOBUFFER - 12) {
 536                         this_part = USBTMC_SIZE_IOBUFFER - 12;
 537                         buffer[8] = 0;
 538                 } else {
 539                         this_part = remaining;
 540                         buffer[8] = 1;
 541                 }
 542
 543                 /* Setup IO buffer for DEV_DEP_MSG_OUT message */
 544                 buffer[0] = 1;
 545                 buffer[1] = data->bTag;
 546                 buffer[2] = ~(data->bTag);
 547                 buffer[3] = 0; /* Reserved */
 548                 buffer[4] = this_part & 255;
 549                 buffer[5] = (this_part >> 8) & 255;
 550                 buffer[6] = (this_part >> 16) & 255;
 551                 buffer[7] = (this_part >> 24) & 255;
 552                 /* buffer[8] is set above... */
 553                 buffer[9] = 0; /* Reserved */
 554                 buffer[10] = 0; /* Reserved */
 555                 buffer[11] = 0; /* Reserved */
 556
 557                 if (copy_from_user(&buffer[12], buf + done, this_part)) {
 558                         retval = -EFAULT;
 559                         goto exit;
 560                 }
 561
 562                 n_bytes = roundup(12 + this_part, 4);
 563                 memset(buffer + 12 + this_part, 0, n_bytes - (12 + this_part));
 564
 565                 do {
 566                         retval = usb_bulk_msg(data->usb_dev,
 567                                               usb_sndbulkpipe(data->usb_dev,
 568                                                               data->bulk_out),
 569                                               buffer, n_bytes,
 570                                               &actual, USBTMC_TIMEOUT);
 571                         if (retval != 0)
 572                                 break;
 573                         n_bytes -= actual;
 574                 } while (n_bytes);
 575
 576                 data->bTag_last_write = data->bTag;
 577                 data->bTag++;
 578
 579                 if (!data->bTag)
 580                         data->bTag++;
 581
 582                 if (retval < 0) {
 583                         dev_err(&data->intf->dev,
 584                                 "Unable to send data, error %d\n", retval);
 585                         if (data->auto_abort)
 586                                 usbtmc_ioctl_abort_bulk_out(data);
 587                         goto exit;
 588                 }
 589
 590                 remaining -= this_part;
 591                 done += this_part;
 592         }
 593
 594         retval = count;
 595 exit:
 596         mutex_unlock(&data->io_mutex);
 597         kfree(buffer);
 598         return retval;
 599 }
 600
 601 static int usbtmc_ioctl_clear(struct usbtmc_device_data *data)
 602 {
 603         struct usb_host_interface *current_setting;
 604         struct usb_endpoint_descriptor *desc;
 605         struct device *dev;
 606         u8 *buffer;
 607         int rv;
 608         int n;
 609         int actual;
 610         int max_size;
 611
 612         dev = &data->intf->dev;
 613
 614         dev_dbg(dev, "Sending INITIATE_CLEAR request\n");
 615
 616         buffer = kmalloc(USBTMC_SIZE_IOBUFFER, GFP_KERNEL);
 617         if (!buffer)
 618                 return -ENOMEM;
 619
 620         rv = usb_control_msg(data->usb_dev,
 621                              usb_rcvctrlpipe(data->usb_dev, 0),
 622                              USBTMC_REQUEST_INITIATE_CLEAR,
 623                              USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE,
 624                              0, 0, buffer, 1, USBTMC_TIMEOUT);
 625         if (rv < 0) {
 626                 dev_err(dev, "usb_control_msg returned %d\n", rv);
 627                 goto exit;
 628         }
 629
 630         dev_dbg(dev, "INITIATE_CLEAR returned %x\n", buffer[0]);
 631
 632         if (buffer[0] != USBTMC_STATUS_SUCCESS) {
 633                 dev_err(dev, "INITIATE_CLEAR returned %x\n", buffer[0]);
 634                 rv = -EPERM;
 635                 goto exit;
 636         }
 637
 638         max_size = 0;
 639         current_setting = data->intf->cur_altsetting;
 640         for (n = 0; n < current_setting->desc.bNumEndpoints; n++) {
 641                 desc = &current_setting->endpoint[n].desc;
 642                 if (desc->bEndpointAddress == data->bulk_in)
 643                         max_size = le16_to_cpu(desc->wMaxPacketSize);
 644         }
 645
 646         if (max_size == 0) {
 647                 dev_err(dev, "Couldn't get wMaxPacketSize\n");
 648                 rv = -EPERM;
 649                 goto exit;
 650         }
 651
 652         dev_dbg(dev, "wMaxPacketSize is %d\n", max_size);
 653
 654         n = 0;
 655
 656 usbtmc_clear_check_status:
 657
 658         dev_dbg(dev, "Sending CHECK_CLEAR_STATUS request\n");
 659
 660         rv = usb_control_msg(data->usb_dev,
 661                              usb_rcvctrlpipe(data->usb_dev, 0),
 662                              USBTMC_REQUEST_CHECK_CLEAR_STATUS,
 663                              USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE,
 664                              0, 0, buffer, 2, USBTMC_TIMEOUT);
 665         if (rv < 0) {
 666                 dev_err(dev, "usb_control_msg returned %d\n", rv);
 667                 goto exit;
 668         }
 669
 670         dev_dbg(dev, "CHECK_CLEAR_STATUS returned %x\n", buffer[0]);
 671
 672         if (buffer[0] == USBTMC_STATUS_SUCCESS)
 673                 goto usbtmc_clear_bulk_out_halt;
 674
 675         if (buffer[0] != USBTMC_STATUS_PENDING) {
 676                 dev_err(dev, "CHECK_CLEAR_STATUS returned %x\n", buffer[0]);
 677                 rv = -EPERM;
 678                 goto exit;
 679         }
 680
 681         if (buffer[1] == 1)
 682                 do {
 683                         dev_dbg(dev, "Reading from bulk in EP\n");
 684
 685                         rv = usb_bulk_msg(data->usb_dev,
 686                                           usb_rcvbulkpipe(data->usb_dev,
 687                                                           data->bulk_in),
 688                                           buffer, USBTMC_SIZE_IOBUFFER,
 689                                           &actual, USBTMC_TIMEOUT);
 690                         n++;
 691
 692                         if (rv < 0) {
 693                                 dev_err(dev, "usb_control_msg returned %d\n",
 694                                         rv);
 695                                 goto exit;
 696                         }
 697                 } while ((actual == max_size) &&
 698                           (n < USBTMC_MAX_READS_TO_CLEAR_BULK_IN));
 699
 700         if (actual == max_size) {
 701                 dev_err(dev, "Couldn't clear device buffer within %d cycles\n",
 702                         USBTMC_MAX_READS_TO_CLEAR_BULK_IN);
 703                 rv = -EPERM;
 704                 goto exit;
 705         }
 706
 707         goto usbtmc_clear_check_status;
 708
 709 usbtmc_clear_bulk_out_halt:
 710
 711         rv = usb_control_msg(data->usb_dev,
 712                              usb_sndctrlpipe(data->usb_dev, 0),
 713                              USB_REQ_CLEAR_FEATURE,
 714                              USB_DIR_OUT | USB_TYPE_STANDARD |
 715                              USB_RECIP_ENDPOINT,
 716                              USB_ENDPOINT_HALT,
 717                              data->bulk_out, buffer, 0,
 718                              USBTMC_TIMEOUT);
 719         if (rv < 0) {
 720                 dev_err(dev, "usb_control_msg returned %d\n", rv);
 721                 goto exit;
 722         }
 723         rv = 0;
 724
 725 exit:
 726         kfree(buffer);
 727         return rv;
 728 }
 729
 730 static int usbtmc_ioctl_clear_out_halt(struct usbtmc_device_data *data)
 731 {
 732         u8 *buffer;
 733         int rv;
 734
 735         buffer = kmalloc(2, GFP_KERNEL);
 736         if (!buffer)
 737                 return -ENOMEM;
 738
 739         rv = usb_control_msg(data->usb_dev,
 740                              usb_sndctrlpipe(data->usb_dev, 0),
 741                              USB_REQ_CLEAR_FEATURE,
 742                              USB_DIR_OUT | USB_TYPE_STANDARD |
 743                              USB_RECIP_ENDPOINT,
 744                              USB_ENDPOINT_HALT, data->bulk_out,
 745                              buffer, 0, USBTMC_TIMEOUT);
 746
 747         if (rv < 0) {
 748                 dev_err(&data->usb_dev->dev, "usb_control_msg returned %d\n",
 749                         rv);
 750                 goto exit;
 751         }
 752         rv = 0;
 753
 754 exit:
 755         kfree(buffer);
 756         return rv;
 757 }
 758
 759 static int usbtmc_ioctl_clear_in_halt(struct usbtmc_device_data *data)
 760 {
 761         u8 *buffer;
 762         int rv;
 763
 764         buffer = kmalloc(2, GFP_KERNEL);
 765         if (!buffer)
 766                 return -ENOMEM;
 767
 768         rv = usb_control_msg(data->usb_dev, usb_sndctrlpipe(data->usb_dev, 0),
 769                              USB_REQ_CLEAR_FEATURE,
 770                              USB_DIR_OUT | USB_TYPE_STANDARD |
 771                              USB_RECIP_ENDPOINT,
 772                              USB_ENDPOINT_HALT, data->bulk_in, buffer, 0,
 773                              USBTMC_TIMEOUT);
 774
 775         if (rv < 0) {
 776                 dev_err(&data->usb_dev->dev, "usb_control_msg returned %d\n",
 777                         rv);
 778                 goto exit;
 779         }
 780         rv = 0;
 781
 782 exit:
 783         kfree(buffer);
 784         return rv;
 785 }
 786
 787 static int get_capabilities(struct usbtmc_device_data *data)
 788 {
 789         struct device *dev = &data->usb_dev->dev;
 790         char *buffer;
 791         int rv = 0;
 792
 793         buffer = kmalloc(0x18, GFP_KERNEL);
 794         if (!buffer)
 795                 return -ENOMEM;
 796
 797         rv = usb_control_msg(data->usb_dev, usb_rcvctrlpipe(data->usb_dev, 0),
 798                              USBTMC_REQUEST_GET_CAPABILITIES,
 799                              USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE,
 800                              0, 0, buffer, 0x18, USBTMC_TIMEOUT);
 801         if (rv < 0) {
 802                 dev_err(dev, "usb_control_msg returned %d\n", rv);
 803                 goto err_out;
 804         }
 805
 806         dev_dbg(dev, "GET_CAPABILITIES returned %x\n", buffer[0]);
 807         if (buffer[0] != USBTMC_STATUS_SUCCESS) {
 808                 dev_err(dev, "GET_CAPABILITIES returned %x\n", buffer[0]);
 809                 rv = -EPERM;
 810                 goto err_out;
 811         }
 812         dev_dbg(dev, "Interface capabilities are %x\n", buffer[4]);
 813         dev_dbg(dev, "Device capabilities are %x\n", buffer[5]);
 814         dev_dbg(dev, "USB488 interface capabilities are %x\n", buffer[14]);
 815         dev_dbg(dev, "USB488 device capabilities are %x\n", buffer[15]);
 816
 817         data->capabilities.interface_capabilities = buffer[4];
 818         data->capabilities.device_capabilities = buffer[5];
 819         data->capabilities.usb488_interface_capabilities = buffer[14];
 820         data->capabilities.usb488_device_capabilities = buffer[15];
 821         rv = 0;
 822
 823 err_out:
 824         kfree(buffer);
 825         return rv;
 826 }
 827
 828 #define capability_attribute(name)                                      \
 829 static ssize_t show_##name(struct device *dev,                          \
 830                            struct device_attribute *attr, char *buf)    \
 831 {                                                                       \
 832         struct usb_interface *intf = to_usb_interface(dev);             \
 833         struct usbtmc_device_data *data = usb_get_intfdata(intf);       \
 834                                                                         \
 835         return sprintf(buf, "%d\n", data->capabilities.name);           \
 836 }                                                                       \
 837 static DEVICE_ATTR(name, S_IRUGO, show_##name, NULL)
 838
 839 capability_attribute(interface_capabilities);
 840 capability_attribute(device_capabilities);
 841 capability_attribute(usb488_interface_capabilities);
 842 capability_attribute(usb488_device_capabilities);
 843
 844 static struct attribute *capability_attrs[] = {
 845         &dev_attr_interface_capabilities.attr,
 846         &dev_attr_device_capabilities.attr,
 847         &dev_attr_usb488_interface_capabilities.attr,
 848         &dev_attr_usb488_device_capabilities.attr,
 849         NULL,
 850 };
 851
 852 static struct attribute_group capability_attr_grp = {
 853         .attrs = capability_attrs,
 854 };
 855
 856 static ssize_t show_TermChar(struct device *dev,
 857                              struct device_attribute *attr, char *buf)
 858 {
 859         struct usb_interface *intf = to_usb_interface(dev);
 860         struct usbtmc_device_data *data = usb_get_intfdata(intf);
 861
 862         return sprintf(buf, "%c\n", data->TermChar);
 863 }
 864
 865 static ssize_t store_TermChar(struct device *dev,
 866                               struct device_attribute *attr,
 867                               const char *buf, size_t count)
 868 {
 869         struct usb_interface *intf = to_usb_interface(dev);
 870         struct usbtmc_device_data *data = usb_get_intfdata(intf);
 871
 872         if (count < 1)
 873                 return -EINVAL;
 874         data->TermChar = buf[0];
 875         return count;
 876 }
 877 static DEVICE_ATTR(TermChar, S_IRUGO, show_TermChar, store_TermChar);
 878
 879 #define data_attribute(name)                                            \
 880 static ssize_t show_##name(struct device *dev,                          \
 881                            struct device_attribute *attr, char *buf)    \
 882 {                                                                       \
 883         struct usb_interface *intf = to_usb_interface(dev);             \
 884         struct usbtmc_device_data *data = usb_get_intfdata(intf);       \
 885                                                                         \
 886         return sprintf(buf, "%d\n", data->name);                        \
 887 }                                                                       \
 888 static ssize_t store_##name(struct device *dev,                         \
 889                             struct device_attribute *attr,              \
 890                             const char *buf, size_t count)              \
 891 {                                                                       \
 892         struct usb_interface *intf = to_usb_interface(dev);             \
 893         struct usbtmc_device_data *data = usb_get_intfdata(intf);       \
 894         ssize_t result;                                                 \
 895         unsigned val;                                                   \
 896                                                                         \
 897         result = sscanf(buf, "%u\n", &val);                             \
 898         if (result != 1)                                                \
 899                 result = -EINVAL;                                       \
 900         data->name = val;                                               \
 901         if (result < 0)                                                 \
 902                 return result;                                          \
 903         else                                                            \
 904                 return count;                                           \
 905 }                                                                       \
 906 static DEVICE_ATTR(name, S_IRUGO, show_##name, store_##name)
 907
 908 data_attribute(TermCharEnabled);
 909 data_attribute(auto_abort);
 910
 911 static struct attribute *data_attrs[] = {
 912         &dev_attr_TermChar.attr,
 913         &dev_attr_TermCharEnabled.attr,
 914         &dev_attr_auto_abort.attr,
 915         NULL,
 916 };
 917
 918 static struct attribute_group data_attr_grp = {
 919         .attrs = data_attrs,
 920 };
 921
 922 static int usbtmc_ioctl_indicator_pulse(struct usbtmc_device_data *data)
 923 {
 924         struct device *dev;
 925         u8 *buffer;
 926         int rv;
 927
 928         dev = &data->intf->dev;
 929
 930         buffer = kmalloc(2, GFP_KERNEL);
 931         if (!buffer)
 932                 return -ENOMEM;
 933
 934         rv = usb_control_msg(data->usb_dev,
 935                              usb_rcvctrlpipe(data->usb_dev, 0),
 936                              USBTMC_REQUEST_INDICATOR_PULSE,
 937                              USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE,
 938                              0, 0, buffer, 0x01, USBTMC_TIMEOUT);
 939
 940         if (rv < 0) {
 941                 dev_err(dev, "usb_control_msg returned %d\n", rv);
 942                 goto exit;
 943         }
 944
 945         dev_dbg(dev, "INDICATOR_PULSE returned %x\n", buffer[0]);
 946
 947         if (buffer[0] != USBTMC_STATUS_SUCCESS) {
 948                 dev_err(dev, "INDICATOR_PULSE returned %x\n", buffer[0]);
 949                 rv = -EPERM;
 950                 goto exit;
 951         }
 952         rv = 0;
 953
 954 exit:
 955         kfree(buffer);
 956         return rv;
 957 }
 958
 959 static long usbtmc_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 960 {
 961         struct usbtmc_device_data *data;
 962         int retval = -EBADRQC;
 963
 964         data = file->private_data;
 965         mutex_lock(&data->io_mutex);
 966         if (data->zombie) {
 967                 retval = -ENODEV;
 968                 goto skip_io_on_zombie;
 969         }
 970
 971         switch (cmd) {
 972         case USBTMC_IOCTL_CLEAR_OUT_HALT:
 973                 retval = usbtmc_ioctl_clear_out_halt(data);
 974                 break;
 975
 976         case USBTMC_IOCTL_CLEAR_IN_HALT:
 977                 retval = usbtmc_ioctl_clear_in_halt(data);
 978                 break;
 979
 980         case USBTMC_IOCTL_INDICATOR_PULSE:
 981                 retval = usbtmc_ioctl_indicator_pulse(data);
 982                 break;
 983
 984         case USBTMC_IOCTL_CLEAR:
 985                 retval = usbtmc_ioctl_clear(data);
 986                 break;
 987
 988         case USBTMC_IOCTL_ABORT_BULK_OUT:
 989                 retval = usbtmc_ioctl_abort_bulk_out(data);
 990                 break;
 991
 992         case USBTMC_IOCTL_ABORT_BULK_IN:
 993                 retval = usbtmc_ioctl_abort_bulk_in(data);
 994                 break;
 995         }
 996
 997 skip_io_on_zombie:
 998         mutex_unlock(&data->io_mutex);
 999         return retval;
1000 }
1001
1002 static const struct file_operations fops = {
1003         .owner          = THIS_MODULE,
1004         .read           = usbtmc_read,
1005         .write          = usbtmc_write,
1006         .open           = usbtmc_open,
1007         .release        = usbtmc_release,
1008         .unlocked_ioctl = usbtmc_ioctl,
1009 };
1010
1011 static struct usb_class_driver usbtmc_class = {
1012         .name =         "usbtmc%d",
1013         .fops =         &fops,
1014         .minor_base =   USBTMC_MINOR_BASE,
1015 };
1016
1017
1018 static int usbtmc_probe(struct usb_interface *intf,
1019                         const struct usb_device_id *id)
1020 {
1021         struct usbtmc_device_data *data;
1022         struct usb_host_interface *iface_desc;
1023         struct usb_endpoint_descriptor *endpoint;
1024         int n;
1025         int retcode;
1026
1027         dev_dbg(&intf->dev, "%s called\n", __func__);
1028
1029         data = kmalloc(sizeof(struct usbtmc_device_data), GFP_KERNEL);
1030         if (!data) {
1031                 dev_err(&intf->dev, "Unable to allocate kernel memory\n");
1032                 return -ENOMEM;
1033         }
1034
1035         data->intf = intf;
1036         data->id = id;
1037         data->usb_dev = usb_get_dev(interface_to_usbdev(intf));
1038         usb_set_intfdata(intf, data);
1039         kref_init(&data->kref);
1040         mutex_init(&data->io_mutex);
1041         data->zombie = 0;
1042
1043         /* Initialize USBTMC bTag and other fields */
1044         data->bTag      = 1;
1045         data->TermCharEnabled = 0;
1046         data->TermChar = '\n';
1047
1048         /* USBTMC devices have only one setting, so use that */
1049         iface_desc = data->intf->cur_altsetting;
1050
1051         /* Find bulk in endpoint */
1052         for (n = 0; n < iface_desc->desc.bNumEndpoints; n++) {
1053                 endpoint = &iface_desc->endpoint[n].desc;
1054
1055                 if (usb_endpoint_is_bulk_in(endpoint)) {
1056                         data->bulk_in = endpoint->bEndpointAddress;
1057                         dev_dbg(&intf->dev, "Found bulk in endpoint at %u\n",
1058                                 data->bulk_in);
1059                         break;
1060                 }
1061         }
1062
1063         /* Find bulk out endpoint */
1064         for (n = 0; n < iface_desc->desc.bNumEndpoints; n++) {
1065                 endpoint = &iface_desc->endpoint[n].desc;
1066
1067                 if (usb_endpoint_is_bulk_out(endpoint)) {
1068                         data->bulk_out = endpoint->bEndpointAddress;
1069                         dev_dbg(&intf->dev, "Found Bulk out endpoint at %u\n",
1070                                 data->bulk_out);
1071                         break;
1072                 }
1073         }
1074
1075         retcode = get_capabilities(data);
1076         if (retcode)
1077                 dev_err(&intf->dev, "can't read capabilities\n");
1078         else
1079                 retcode = sysfs_create_group(&intf->dev.kobj,
1080                                              &capability_attr_grp);
1081
1082         retcode = sysfs_create_group(&intf->dev.kobj, &data_attr_grp);
1083
1084         retcode = usb_register_dev(intf, &usbtmc_class);
1085         if (retcode) {
1086                 dev_err(&intf->dev, "Not able to get a minor"
1087                         " (base %u, slice default): %d\n", USBTMC_MINOR_BASE,
1088                         retcode);
1089                 goto error_register;
1090         }
1091         dev_dbg(&intf->dev, "Using minor number %d\n", intf->minor);
1092
1093         return 0;
1094
1095 error_register:
1096         sysfs_remove_group(&intf->dev.kobj, &capability_attr_grp);
1097         sysfs_remove_group(&intf->dev.kobj, &data_attr_grp);
1098         kref_put(&data->kref, usbtmc_delete);
1099         return retcode;
1100 }
1101
1102 static void usbtmc_disconnect(struct usb_interface *intf)
1103 {
1104         struct usbtmc_device_data *data;
1105
1106         dev_dbg(&intf->dev, "usbtmc_disconnect called\n");
1107
1108         data = usb_get_intfdata(intf);
1109         usb_deregister_dev(intf, &usbtmc_class);
1110         sysfs_remove_group(&intf->dev.kobj, &capability_attr_grp);
1111         sysfs_remove_group(&intf->dev.kobj, &data_attr_grp);
1112         mutex_lock(&data->io_mutex);
1113         data->zombie = 1;
1114         mutex_unlock(&data->io_mutex);
1115         kref_put(&data->kref, usbtmc_delete);
1116 }
1117
1118 static int usbtmc_suspend(struct usb_interface *intf, pm_message_t message)
1119 {
1120         /* this driver does not have pending URBs */
1121         return 0;
1122 }
1123
1124 static int usbtmc_resume(struct usb_interface *intf)
1125 {
1126         return 0;
1127 }
1128
1129 static struct usb_driver usbtmc_driver = {
1130         .name           = "usbtmc",
1131         .id_table       = usbtmc_devices,
1132         .probe          = usbtmc_probe,
1133         .disconnect     = usbtmc_disconnect,
1134         .suspend        = usbtmc_suspend,
1135         .resume         = usbtmc_resume,
1136 };
1137
1138 static int __init usbtmc_init(void)
1139 {
1140         int retcode;
1141
1142         retcode = usb_register(&usbtmc_driver);
1143         if (retcode)
1144                 printk(KERN_ERR KBUILD_MODNAME": Unable to register driver\n");
1145         return retcode;
1146 }
1147 module_init(usbtmc_init);
1148
1149 static void __exit usbtmc_exit(void)
1150 {
1151         usb_deregister(&usbtmc_driver);
1152 }
1153 module_exit(usbtmc_exit);
1154
1155 MODULE_LICENSE("GPL");