src/scpi/scpi_usbtmc_libusb.c

   1 /*
   2  * This file is part of the libsigrok project.
   3  *
   4  * Copyright (C) 2014 Aurelien Jacobs <aurel@gnuage.org>
   5  *
   6  * This program is free software: you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation, either version 3 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 #include <config.h>
  21 #include <string.h>
  22 #include <libsigrok/libsigrok.h>
  23 #include "libsigrok-internal.h"
  24 #include "scpi.h"
  25
  26 #define LOG_PREFIX "scpi_usbtmc"
  27
  28 #define MAX_TRANSFER_LENGTH 2048
  29 #define TRANSFER_TIMEOUT 1000
  30
  31 struct scpi_usbtmc_libusb {
  32         struct sr_context *ctx;
  33         struct sr_usb_dev_inst *usb;
  34         int detached_kernel_driver;
  35         uint8_t interface;
  36         uint8_t bulk_in_ep;
  37         uint8_t bulk_out_ep;
  38         uint8_t interrupt_ep;
  39         uint8_t usbtmc_int_cap;
  40         uint8_t usbtmc_dev_cap;
  41         uint8_t usb488_dev_cap;
  42         uint8_t bTag;
  43         uint8_t bulkin_attributes;
  44         uint8_t buffer[MAX_TRANSFER_LENGTH];
  45         int response_length;
  46         int response_bytes_read;
  47         int remaining_length;
  48         int rigol_ds1000;
  49 };
  50
  51 /* Some USBTMC-specific enums, as defined in the USBTMC standard. */
  52 #define SUBCLASS_USBTMC  0x03
  53 #define USBTMC_USB488    0x01
  54
  55 enum {
  56         /* USBTMC control requests */
  57         INITIATE_ABORT_BULK_OUT     =   1,
  58         CHECK_ABORT_BULK_OUT_STATUS =   2,
  59         INITIATE_ABORT_BULK_IN      =   3,
  60         CHECK_ABORT_BULK_IN_STATUS  =   4,
  61         INITIATE_CLEAR              =   5,
  62         CHECK_CLEAR_STATUS          =   6,
  63         GET_CAPABILITIES            =   7,
  64         INDICATOR_PULSE             =  64,
  65
  66         /* USB488 control requests */
  67         READ_STATUS_BYTE            = 128,
  68         REN_CONTROL                 = 160,
  69         GO_TO_LOCAL                 = 161,
  70         LOCAL_LOCKOUT               = 162,
  71 };
  72
  73 /* USBTMC status codes */
  74 #define USBTMC_STATUS_SUCCESS      0x01
  75
  76 /* USBTMC capabilities */
  77 #define USBTMC_INT_CAP_LISTEN_ONLY 0x01
  78 #define USBTMC_INT_CAP_TALK_ONLY   0x02
  79 #define USBTMC_INT_CAP_INDICATOR   0x04
  80
  81 #define USBTMC_DEV_CAP_TERMCHAR    0x01
  82
  83 #define USB488_DEV_CAP_DT1         0x01
  84 #define USB488_DEV_CAP_RL1         0x02
  85 #define USB488_DEV_CAP_SR1         0x04
  86 #define USB488_DEV_CAP_SCPI        0x08
  87
  88 /* Bulk messages constants */
  89 #define USBTMC_BULK_HEADER_SIZE  12
  90
  91 /* Bulk MsgID values */
  92 #define DEV_DEP_MSG_OUT         1
  93 #define REQUEST_DEV_DEP_MSG_IN  2
  94 #define DEV_DEP_MSG_IN          2
  95
  96 /* bmTransferAttributes */
  97 #define EOM                0x01
  98 #define TERM_CHAR_ENABLED  0x02
  99
 100 struct usbtmc_blacklist {
 101         uint16_t vid;
 102         uint16_t pid;
 103 };
 104
 105 static struct usbtmc_blacklist blacklist_remote[] = {
 106         /* Rigol DS1000 series publishes RL1 support, but doesn't support it. */
 107         { 0x1ab1, 0x0588 },
 108         ALL_ZERO
 109 };
 110
 111 static GSList *scpi_usbtmc_libusb_scan(struct drv_context *drvc)
 112 {
 113         struct libusb_device **devlist;
 114         struct libusb_device_descriptor des;
 115         struct libusb_config_descriptor *confdes;
 116         const struct libusb_interface_descriptor *intfdes;
 117         GSList *resources = NULL;
 118         int confidx, intfidx, ret, i;
 119         char *res;
 120
 121         ret = libusb_get_device_list(drvc->sr_ctx->libusb_ctx, &devlist);
 122         if (ret < 0) {
 123                 sr_err("Failed to get device list: %s.",
 124                        libusb_error_name(ret));
 125                 return NULL;
 126         }
 127         for (i = 0; devlist[i]; i++) {
 128                 libusb_get_device_descriptor(devlist[i], &des);
 129
 130                 for (confidx = 0; confidx < des.bNumConfigurations; confidx++) {
 131                         if ((ret = libusb_get_config_descriptor(devlist[i], confidx, &confdes)) < 0) {
 132                                 sr_dbg("Failed to get configuration descriptor: %s, "
 133                                        "ignoring device.", libusb_error_name(ret));
 134                                 break;
 135                         }
 136                         for (intfidx = 0; intfidx < confdes->bNumInterfaces; intfidx++) {
 137                                 intfdes = confdes->interface[intfidx].altsetting;
 138                                 if (intfdes->bInterfaceClass    != LIBUSB_CLASS_APPLICATION ||
 139                                     intfdes->bInterfaceSubClass != SUBCLASS_USBTMC          ||
 140                                     intfdes->bInterfaceProtocol != USBTMC_USB488)
 141                                         continue;
 142                                 sr_dbg("Found USBTMC device (VID:PID = %04x:%04x, "
 143                                        "bus.address = %d.%d).", des.idVendor, des.idProduct,
 144                                        libusb_get_bus_number(devlist[i]),
 145                                        libusb_get_device_address(devlist[i]));
 146                                 res = g_strdup_printf("usbtmc/%d.%d",
 147                                                       libusb_get_bus_number(devlist[i]),
 148                                                       libusb_get_device_address(devlist[i]));
 149                                 resources = g_slist_append(resources, res);
 150                         }
 151                         libusb_free_config_descriptor(confdes);
 152                 }
 153         }
 154         libusb_free_device_list(devlist, 1);
 155
 156         sr_dbg("Found %d device(s).", g_slist_length(resources));
 157
 158         return resources;
 159 }
 160
 161 static int scpi_usbtmc_libusb_dev_inst_new(void *priv, struct drv_context *drvc,
 162                 const char *resource, char **params, const char *serialcomm)
 163 {
 164         struct scpi_usbtmc_libusb *uscpi = priv;
 165         GSList *devices;
 166
 167         (void)resource;
 168         (void)serialcomm;
 169
 170         if (!params || !params[1]) {
 171                 sr_err("Invalid parameters.");
 172                 return SR_ERR;
 173         }
 174
 175         uscpi->ctx = drvc->sr_ctx;
 176         devices = sr_usb_find(uscpi->ctx->libusb_ctx, params[1]);
 177         if (g_slist_length(devices) != 1) {
 178                 sr_err("Failed to find USB device '%s'.", params[1]);
 179                 g_slist_free_full(devices, (GDestroyNotify)sr_usb_dev_inst_free);
 180                 return SR_ERR;
 181         }
 182         uscpi->usb = devices->data;
 183         g_slist_free(devices);
 184
 185         return SR_OK;
 186 }
 187
 188 static int check_usbtmc_blacklist(struct usbtmc_blacklist *blacklist,
 189                 uint16_t vid, uint16_t pid)
 190 {
 191         int i;
 192
 193         for (i = 0; blacklist[i].vid; i++) {
 194                 if (blacklist[i].vid == vid && blacklist[i].pid == pid)
 195                         return TRUE;
 196         }
 197
 198         return FALSE;
 199 }
 200
 201 static int scpi_usbtmc_remote(struct scpi_usbtmc_libusb *uscpi)
 202 {
 203         struct sr_usb_dev_inst *usb = uscpi->usb;
 204         struct libusb_device *dev;
 205         struct libusb_device_descriptor des;
 206         int ret;
 207         uint8_t status;
 208
 209         if (!(uscpi->usb488_dev_cap & USB488_DEV_CAP_RL1))
 210                 return SR_OK;
 211
 212         dev = libusb_get_device(usb->devhdl);
 213         libusb_get_device_descriptor(dev, &des);
 214         if (check_usbtmc_blacklist(blacklist_remote, des.idVendor, des.idProduct))
 215                 return SR_OK;
 216
 217         sr_dbg("Locking out local control.");
 218         ret = libusb_control_transfer(usb->devhdl,
 219                         LIBUSB_ENDPOINT_IN         |
 220                         LIBUSB_REQUEST_TYPE_CLASS  |
 221                         LIBUSB_RECIPIENT_INTERFACE,
 222                         REN_CONTROL, 1,
 223                         uscpi->interface,
 224                         &status, 1,
 225                         TRANSFER_TIMEOUT);
 226         if (ret < 0 || status != USBTMC_STATUS_SUCCESS) {
 227                 if (ret < 0)
 228                         sr_dbg("Failed to enter REN state: %s.", libusb_error_name(ret));
 229                 else
 230                         sr_dbg("Failed to enter REN state: USBTMC status %d.", status);
 231                 return SR_ERR;
 232         }
 233
 234         ret = libusb_control_transfer(usb->devhdl,
 235                         LIBUSB_ENDPOINT_IN         |
 236                         LIBUSB_REQUEST_TYPE_CLASS  |
 237                         LIBUSB_RECIPIENT_INTERFACE,
 238                         LOCAL_LOCKOUT, 1,
 239                         uscpi->interface,
 240                         &status, 1,
 241                         TRANSFER_TIMEOUT);
 242         if (ret < 0 || status != USBTMC_STATUS_SUCCESS) {
 243                 if (ret < 0)
 244                         sr_dbg("Failed to enter local lockout state: %s.",
 245                                         libusb_error_name(ret));
 246                 else
 247                         sr_dbg("Failed to enter local lockout state: USBTMC "
 248                                         "status %d.", status);
 249                 return SR_ERR;
 250         }
 251
 252         return SR_OK;
 253 }
 254
 255 static void scpi_usbtmc_local(struct scpi_usbtmc_libusb *uscpi)
 256 {
 257         struct sr_usb_dev_inst *usb = uscpi->usb;
 258         struct libusb_device *dev;
 259         struct libusb_device_descriptor des;
 260         int ret;
 261         uint8_t status;
 262
 263         if (!(uscpi->usb488_dev_cap & USB488_DEV_CAP_RL1))
 264                 return;
 265
 266         dev = libusb_get_device(usb->devhdl);
 267         libusb_get_device_descriptor(dev, &des);
 268         if (check_usbtmc_blacklist(blacklist_remote, des.idVendor, des.idProduct))
 269                 return;
 270
 271         sr_dbg("Returning local control.");
 272         ret = libusb_control_transfer(usb->devhdl,
 273                         LIBUSB_ENDPOINT_IN         |
 274                         LIBUSB_REQUEST_TYPE_CLASS  |
 275                         LIBUSB_RECIPIENT_INTERFACE,
 276                         GO_TO_LOCAL, 1,
 277                         uscpi->interface,
 278                         &status, 1,
 279                         TRANSFER_TIMEOUT);
 280         if (ret < 0 || status != USBTMC_STATUS_SUCCESS) {
 281                 if (ret < 0)
 282                         sr_dbg("Failed to clear local lockout state: %s.",
 283                                         libusb_error_name(ret));
 284                 else
 285                         sr_dbg("Failed to clear local lockout state: USBTMC "
 286                                         "status %d.", status);
 287         }
 288
 289         return;
 290 }
 291
 292 static int scpi_usbtmc_libusb_open(struct sr_scpi_dev_inst *scpi)
 293 {
 294         struct scpi_usbtmc_libusb *uscpi = scpi->priv;
 295         struct sr_usb_dev_inst *usb = uscpi->usb;
 296         struct libusb_device *dev;
 297         struct libusb_device_descriptor des;
 298         struct libusb_config_descriptor *confdes;
 299         const struct libusb_interface_descriptor *intfdes;
 300         const struct libusb_endpoint_descriptor *ep;
 301         int confidx, intfidx, epidx, config = 0;
 302         uint8_t capabilities[24];
 303         int ret, found = 0;
 304
 305         if (usb->devhdl)
 306                 return SR_OK;
 307
 308         if (sr_usb_open(uscpi->ctx->libusb_ctx, usb) != SR_OK)
 309                 return SR_ERR;
 310
 311         dev = libusb_get_device(usb->devhdl);
 312         libusb_get_device_descriptor(dev, &des);
 313
 314         for (confidx = 0; confidx < des.bNumConfigurations; confidx++) {
 315                 if ((ret = libusb_get_config_descriptor(dev, confidx, &confdes)) < 0) {
 316                         sr_dbg("Failed to get configuration descriptor: %s, "
 317                                "ignoring device.", libusb_error_name(ret));
 318                         continue;
 319                 }
 320                 for (intfidx = 0; intfidx < confdes->bNumInterfaces; intfidx++) {
 321                         intfdes = confdes->interface[intfidx].altsetting;
 322                         if (intfdes->bInterfaceClass    != LIBUSB_CLASS_APPLICATION ||
 323                             intfdes->bInterfaceSubClass != SUBCLASS_USBTMC          ||
 324                             intfdes->bInterfaceProtocol != USBTMC_USB488)
 325                                 continue;
 326                         uscpi->interface = intfdes->bInterfaceNumber;
 327                         config = confdes->bConfigurationValue;
 328                         sr_dbg("Interface %d configuration %d.", uscpi->interface, config);
 329                         for (epidx = 0; epidx < intfdes->bNumEndpoints; epidx++) {
 330                                 ep = &intfdes->endpoint[epidx];
 331                                 if (ep->bmAttributes == LIBUSB_TRANSFER_TYPE_BULK &&
 332                                     !(ep->bEndpointAddress & (LIBUSB_ENDPOINT_DIR_MASK))) {
 333                                         uscpi->bulk_out_ep = ep->bEndpointAddress;
 334                                         sr_dbg("Bulk OUT EP %d", uscpi->bulk_out_ep);
 335                                 }
 336                                 if (ep->bmAttributes == LIBUSB_TRANSFER_TYPE_BULK &&
 337                                     ep->bEndpointAddress & (LIBUSB_ENDPOINT_DIR_MASK)) {
 338                                         uscpi->bulk_in_ep = ep->bEndpointAddress;
 339                                         sr_dbg("Bulk IN EP %d", uscpi->bulk_in_ep & 0x7f);
 340                                 }
 341                                 if (ep->bmAttributes == LIBUSB_TRANSFER_TYPE_INTERRUPT &&
 342                                     ep->bEndpointAddress & (LIBUSB_ENDPOINT_DIR_MASK)) {
 343                                         uscpi->interrupt_ep = ep->bEndpointAddress;
 344                                         sr_dbg("Interrupt EP %d", uscpi->interrupt_ep & 0x7f);
 345                                 }
 346                         }
 347                         found = 1;
 348                         uscpi->rigol_ds1000 = des.idVendor  == 0x1ab1 &&
 349                                               des.idProduct == 0x0588;
 350                 }
 351                 libusb_free_config_descriptor(confdes);
 352                 if (found)
 353                         break;
 354         }
 355
 356         if (!found) {
 357                 sr_err("Failed to find USBTMC interface.");
 358                 return SR_ERR;
 359         }
 360
 361         if (libusb_kernel_driver_active(usb->devhdl, uscpi->interface) == 1) {
 362                 if ((ret = libusb_detach_kernel_driver(usb->devhdl,
 363                                                        uscpi->interface)) < 0) {
 364                         sr_err("Failed to detach kernel driver: %s.",
 365                                libusb_error_name(ret));
 366                         return SR_ERR;
 367                 }
 368                 uscpi->detached_kernel_driver = 1;
 369         }
 370
 371         if ((ret = libusb_set_configuration(usb->devhdl, config)) < 0) {
 372                 sr_err("Failed to set configuration: %s.",
 373                        libusb_error_name(ret));
 374                 return SR_ERR;
 375         }
 376
 377         if ((ret = libusb_claim_interface(usb->devhdl, uscpi->interface)) < 0) {
 378                 sr_err("Failed to claim interface: %s.",
 379                        libusb_error_name(ret));
 380                 return SR_ERR;
 381         }
 382
 383         if (!uscpi->rigol_ds1000) {
 384         if ((ret = libusb_clear_halt(usb->devhdl, uscpi->bulk_in_ep)) < 0) {
 385                 sr_err("Failed to clear halt/stall condition for EP %d: %s.",
 386                        uscpi->bulk_in_ep, libusb_error_name(ret));
 387                 return SR_ERR;
 388         }
 389         if ((ret = libusb_clear_halt(usb->devhdl, uscpi->bulk_out_ep)) < 0) {
 390                 sr_err("Failed to clear halt/stall condition for EP %d: %s.",
 391                        uscpi->bulk_out_ep, libusb_error_name(ret));
 392                 return SR_ERR;
 393         }
 394         if ((ret = libusb_clear_halt(usb->devhdl, uscpi->interrupt_ep)) < 0) {
 395                 sr_err("Failed to clear halt/stall condition for EP %d: %s.",
 396                        uscpi->interrupt_ep, libusb_error_name(ret));
 397                 return SR_ERR;
 398         }
 399         }
 400
 401         /* Get capabilities. */
 402         ret = libusb_control_transfer(usb->devhdl,
 403                                       LIBUSB_ENDPOINT_IN         |
 404                                       LIBUSB_REQUEST_TYPE_CLASS  |
 405                                       LIBUSB_RECIPIENT_INTERFACE,
 406                                       GET_CAPABILITIES, 0,
 407                                       uscpi->interface,
 408                                       capabilities, sizeof(capabilities),
 409                                       TRANSFER_TIMEOUT);
 410         if (ret == sizeof(capabilities)) {
 411                 uscpi->usbtmc_int_cap = capabilities[ 4];
 412                 uscpi->usbtmc_dev_cap = capabilities[ 5];
 413                 uscpi->usb488_dev_cap = capabilities[15];
 414         }
 415         sr_dbg("Device capabilities: %s%s%s%s%s, %s, %s",
 416                uscpi->usb488_dev_cap & USB488_DEV_CAP_SCPI       ? "SCPI, "    : "",
 417                uscpi->usbtmc_dev_cap & USBTMC_DEV_CAP_TERMCHAR   ? "TermChar, ": "",
 418                uscpi->usbtmc_int_cap & USBTMC_INT_CAP_LISTEN_ONLY? "L3, " :
 419                uscpi->usbtmc_int_cap & USBTMC_INT_CAP_TALK_ONLY  ? ""     : "L4, ",
 420                uscpi->usbtmc_int_cap & USBTMC_INT_CAP_TALK_ONLY  ? "T5, " :
 421                uscpi->usbtmc_int_cap & USBTMC_INT_CAP_LISTEN_ONLY? ""     : "T6, ",
 422                uscpi->usb488_dev_cap & USB488_DEV_CAP_SR1        ? "SR1"  : "SR0",
 423                uscpi->usb488_dev_cap & USB488_DEV_CAP_RL1        ? "RL1"  : "RL0",
 424                uscpi->usb488_dev_cap & USB488_DEV_CAP_DT1        ? "DT1"  : "DT0");
 425
 426         scpi_usbtmc_remote(uscpi);
 427
 428         return SR_OK;
 429 }
 430
 431 static int scpi_usbtmc_libusb_source_add(struct sr_session *session,
 432                 void *priv, int events, int timeout, sr_receive_data_callback cb,
 433                 void *cb_data)
 434 {
 435         struct scpi_usbtmc_libusb *uscpi = priv;
 436         (void)events;
 437         return usb_source_add(session, uscpi->ctx, timeout, cb, cb_data);
 438 }
 439
 440 static int scpi_usbtmc_libusb_source_remove(struct sr_session *session,
 441                 void *priv)
 442 {
 443         struct scpi_usbtmc_libusb *uscpi = priv;
 444         return usb_source_remove(session, uscpi->ctx);
 445 }
 446
 447 static void usbtmc_bulk_out_header_write(void *header, uint8_t MsgID,
 448                                          uint8_t bTag,
 449                                          uint32_t TransferSize,
 450                                          uint8_t bmTransferAttributes,
 451                                          char TermChar)
 452 {
 453           W8(header+ 0, MsgID);
 454           W8(header+ 1, bTag);
 455           W8(header+ 2, ~bTag);
 456           W8(header+ 3, 0);
 457         WL32(header+ 4, TransferSize);
 458           W8(header+ 8, bmTransferAttributes);
 459           W8(header+ 9, TermChar);
 460         WL16(header+10, 0);
 461 }
 462
 463 static int usbtmc_bulk_in_header_read(void *header, uint8_t MsgID,
 464                                       unsigned char bTag,
 465                                       int32_t *TransferSize,
 466                                       uint8_t *bmTransferAttributes)
 467 {
 468         if (R8(header+0) != MsgID ||
 469             R8(header+1) != bTag  ||
 470             R8(header+2) != (unsigned char)~bTag)
 471                 return SR_ERR;
 472         if (TransferSize)
 473                 *TransferSize = RL32(header+4);
 474         if (bmTransferAttributes)
 475                 *bmTransferAttributes = R8(header+8);
 476         return SR_OK;
 477 }
 478
 479 static int scpi_usbtmc_bulkout(struct scpi_usbtmc_libusb *uscpi,
 480                                uint8_t msg_id, const void *data, int32_t size,
 481                                uint8_t transfer_attributes)
 482 {
 483         struct sr_usb_dev_inst *usb = uscpi->usb;
 484         int padded_size, ret, transferred;
 485
 486         if (data && size+USBTMC_BULK_HEADER_SIZE+3 > (int)sizeof(uscpi->buffer)) {
 487                 sr_err("USBTMC bulk out transfer is too big.");
 488                 return SR_ERR;
 489         }
 490
 491         uscpi->bTag++;
 492         uscpi->bTag += !uscpi->bTag;  /* bTag == 0 is invalid so avoid it. */
 493
 494         usbtmc_bulk_out_header_write(uscpi->buffer, msg_id, uscpi->bTag,
 495                                      size, transfer_attributes, 0);
 496         if (data)
 497                 memcpy(uscpi->buffer+USBTMC_BULK_HEADER_SIZE, data, size);
 498         else
 499                 size = 0;
 500         size += USBTMC_BULK_HEADER_SIZE;
 501         padded_size = (size + 3) & ~0x3;
 502         memset(uscpi->buffer+size, 0, padded_size - size);
 503
 504         ret = libusb_bulk_transfer(usb->devhdl, uscpi->bulk_out_ep,
 505                                    uscpi->buffer, padded_size, &transferred,
 506                                    TRANSFER_TIMEOUT);
 507         if (ret < 0) {
 508                 sr_err("USBTMC bulk out transfer error: %s.",
 509                        libusb_error_name(ret));
 510                 return SR_ERR;
 511         }
 512
 513         if (transferred < padded_size) {
 514                 sr_dbg("USBTMC bulk out partial transfer (%d/%d bytes).",
 515                        transferred, padded_size);
 516                 return SR_ERR;
 517         }
 518
 519         return transferred - USBTMC_BULK_HEADER_SIZE;
 520 }
 521
 522 static int scpi_usbtmc_bulkin_start(struct scpi_usbtmc_libusb *uscpi,
 523                                     uint8_t msg_id, void *data, int32_t size,
 524                                     uint8_t *transfer_attributes)
 525 {
 526         struct sr_usb_dev_inst *usb = uscpi->usb;
 527         int ret, transferred, message_size;
 528
 529         ret = libusb_bulk_transfer(usb->devhdl, uscpi->bulk_in_ep, data, size,
 530                                    &transferred, TRANSFER_TIMEOUT);
 531         if (ret < 0) {
 532                 sr_err("USBTMC bulk in transfer error: %s.",
 533                        libusb_error_name(ret));
 534                 return SR_ERR;
 535         }
 536
 537         if (usbtmc_bulk_in_header_read(data, msg_id, uscpi->bTag, &message_size,
 538                                        transfer_attributes) != SR_OK) {
 539                 sr_err("USBTMC invalid bulk in header.");
 540                 return SR_ERR;
 541         }
 542
 543         message_size += USBTMC_BULK_HEADER_SIZE;
 544         uscpi->response_length = MIN(transferred, message_size);
 545         uscpi->response_bytes_read = USBTMC_BULK_HEADER_SIZE;
 546         uscpi->remaining_length = message_size - uscpi->response_length;
 547
 548         return transferred - USBTMC_BULK_HEADER_SIZE;
 549 }
 550
 551 static int scpi_usbtmc_bulkin_continue(struct scpi_usbtmc_libusb *uscpi,
 552                                        void *data, int size)
 553 {
 554         struct sr_usb_dev_inst *usb = uscpi->usb;
 555         int ret, transferred;
 556
 557         ret = libusb_bulk_transfer(usb->devhdl, uscpi->bulk_in_ep, data, size,
 558                                    &transferred, TRANSFER_TIMEOUT);
 559         if (ret < 0) {
 560                 sr_err("USBTMC bulk in transfer error: %s.",
 561                        libusb_error_name(ret));
 562                 return SR_ERR;
 563         }
 564
 565         uscpi->response_length = MIN(transferred, uscpi->remaining_length);
 566         uscpi->response_bytes_read = 0;
 567         uscpi->remaining_length -= uscpi->response_length;
 568
 569         return transferred;
 570 }
 571
 572 static int scpi_usbtmc_libusb_send(void *priv, const char *command)
 573 {
 574         struct scpi_usbtmc_libusb *uscpi = priv;
 575
 576         if (scpi_usbtmc_bulkout(uscpi, DEV_DEP_MSG_OUT,
 577                                 command, strlen(command), EOM) <= 0)
 578                 return SR_ERR;
 579
 580         sr_spew("Successfully sent SCPI command: '%s'.", command);
 581
 582         return SR_OK;
 583 }
 584
 585 static int scpi_usbtmc_libusb_read_begin(void *priv)
 586 {
 587         struct scpi_usbtmc_libusb *uscpi = priv;
 588
 589         uscpi->remaining_length = 0;
 590
 591         if (scpi_usbtmc_bulkout(uscpi, REQUEST_DEV_DEP_MSG_IN,
 592             NULL, INT32_MAX, 0) < 0)
 593                 return SR_ERR;
 594         if (scpi_usbtmc_bulkin_start(uscpi, DEV_DEP_MSG_IN,
 595                                      uscpi->buffer, sizeof(uscpi->buffer),
 596                                      &uscpi->bulkin_attributes) < 0)
 597                 return SR_ERR;
 598
 599         return SR_OK;
 600 }
 601
 602 static int scpi_usbtmc_libusb_read_data(void *priv, char *buf, int maxlen)
 603 {
 604         struct scpi_usbtmc_libusb *uscpi = priv;
 605         int read_length;
 606
 607         if (uscpi->response_bytes_read >= uscpi->response_length) {
 608                 if (uscpi->remaining_length > 0) {
 609                         if (scpi_usbtmc_bulkin_continue(uscpi, uscpi->buffer,
 610                                                         sizeof(uscpi->buffer)) <= 0)
 611                                 return SR_ERR;
 612                 } else {
 613                         if (uscpi->bulkin_attributes & EOM)
 614                                 return SR_ERR;
 615                         if (scpi_usbtmc_libusb_read_begin(uscpi) < 0)
 616                                 return SR_ERR;
 617                 }
 618         }
 619
 620         read_length = MIN(uscpi->response_length - uscpi->response_bytes_read, maxlen);
 621
 622         memcpy(buf, uscpi->buffer + uscpi->response_bytes_read, read_length);
 623
 624         uscpi->response_bytes_read += read_length;
 625
 626         return read_length;
 627 }
 628
 629 static int scpi_usbtmc_libusb_read_complete(void *priv)
 630 {
 631         struct scpi_usbtmc_libusb *uscpi = priv;
 632         return uscpi->response_bytes_read >= uscpi->response_length &&
 633                uscpi->remaining_length <= 0 &&
 634                uscpi->bulkin_attributes & EOM;
 635 }
 636
 637 static int scpi_usbtmc_libusb_close(struct sr_scpi_dev_inst *scpi)
 638 {
 639         struct scpi_usbtmc_libusb *uscpi = scpi->priv;
 640         struct sr_usb_dev_inst *usb = uscpi->usb;
 641         int ret;
 642
 643         if (!usb->devhdl)
 644                 return SR_ERR;
 645
 646         if (!uscpi->rigol_ds1000) {
 647         if ((ret = libusb_clear_halt(usb->devhdl, uscpi->bulk_in_ep)) < 0)
 648                 sr_err("Failed to clear halt/stall condition for EP %d: %s.",
 649                        uscpi->bulk_in_ep, libusb_error_name(ret));
 650         if ((ret = libusb_clear_halt(usb->devhdl, uscpi->bulk_out_ep)) < 0)
 651                 sr_err("Failed to clear halt/stall condition for EP %d: %s.",
 652                        uscpi->bulk_out_ep, libusb_error_name(ret));
 653         if ((ret = libusb_clear_halt(usb->devhdl, uscpi->interrupt_ep)) < 0)
 654                 sr_err("Failed to clear halt/stall condition for EP %d: %s.",
 655                        uscpi->interrupt_ep, libusb_error_name(ret));
 656         }
 657
 658         scpi_usbtmc_local(uscpi);
 659
 660         if ((ret = libusb_release_interface(usb->devhdl, uscpi->interface)) < 0)
 661                 sr_err("Failed to release interface: %s.",
 662                        libusb_error_name(ret));
 663
 664         if (uscpi->detached_kernel_driver) {
 665                 if ((ret = libusb_attach_kernel_driver(usb->devhdl,
 666                                                 uscpi->interface)) < 0)
 667                         sr_err("Failed to re-attach kernel driver: %s.",
 668                                libusb_error_name(ret));
 669
 670                 uscpi->detached_kernel_driver = 0;
 671         }
 672         sr_usb_close(usb);
 673
 674         return SR_OK;
 675 }
 676
 677 static void scpi_usbtmc_libusb_free(void *priv)
 678 {
 679         struct scpi_usbtmc_libusb *uscpi = priv;
 680         sr_usb_dev_inst_free(uscpi->usb);
 681 }
 682
 683 SR_PRIV const struct sr_scpi_dev_inst scpi_usbtmc_libusb_dev = {
 684         .name          = "USBTMC",
 685         .prefix        = "usbtmc",
 686         .priv_size     = sizeof(struct scpi_usbtmc_libusb),
 687         .scan          = scpi_usbtmc_libusb_scan,
 688         .dev_inst_new  = scpi_usbtmc_libusb_dev_inst_new,
 689         .open          = scpi_usbtmc_libusb_open,
 690         .source_add    = scpi_usbtmc_libusb_source_add,
 691         .source_remove = scpi_usbtmc_libusb_source_remove,
 692         .send          = scpi_usbtmc_libusb_send,
 693         .read_begin    = scpi_usbtmc_libusb_read_begin,
 694         .read_data     = scpi_usbtmc_libusb_read_data,
 695         .read_complete = scpi_usbtmc_libusb_read_complete,
 696         .close         = scpi_usbtmc_libusb_close,
 697         .free          = scpi_usbtmc_libusb_free,
 698 };