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 };
  49
  50 /* Some USBTMC-specific enums, as defined in the USBTMC standard. */
  51 #define SUBCLASS_USBTMC  0x03
  52 #define USBTMC_USB488    0x01
  53
  54 enum {
  55         /* USBTMC control requests */
  56         INITIATE_ABORT_BULK_OUT     =   1,
  57         CHECK_ABORT_BULK_OUT_STATUS =   2,
  58         INITIATE_ABORT_BULK_IN      =   3,
  59         CHECK_ABORT_BULK_IN_STATUS  =   4,
  60         INITIATE_CLEAR              =   5,
  61         CHECK_CLEAR_STATUS          =   6,
  62         GET_CAPABILITIES            =   7,
  63         INDICATOR_PULSE             =  64,
  64
  65         /* USB488 control requests */
  66         READ_STATUS_BYTE            = 128,
  67         REN_CONTROL                 = 160,
  68         GO_TO_LOCAL                 = 161,
  69         LOCAL_LOCKOUT               = 162,
  70 };
  71
  72 /* USBTMC status codes */
  73 #define USBTMC_STATUS_SUCCESS      0x01
  74
  75 /* USBTMC capabilities */
  76 #define USBTMC_INT_CAP_LISTEN_ONLY 0x01
  77 #define USBTMC_INT_CAP_TALK_ONLY   0x02
  78 #define USBTMC_INT_CAP_INDICATOR   0x04
  79
  80 #define USBTMC_DEV_CAP_TERMCHAR    0x01
  81
  82 #define USB488_DEV_CAP_DT1         0x01
  83 #define USB488_DEV_CAP_RL1         0x02
  84 #define USB488_DEV_CAP_SR1         0x04
  85 #define USB488_DEV_CAP_SCPI        0x08
  86
  87 /* Bulk messages constants */
  88 #define USBTMC_BULK_HEADER_SIZE  12
  89
  90 /* Bulk MsgID values */
  91 #define DEV_DEP_MSG_OUT         1
  92 #define REQUEST_DEV_DEP_MSG_IN  2
  93 #define DEV_DEP_MSG_IN          2
  94
  95 /* bmTransferAttributes */
  96 #define EOM                0x01
  97 #define TERM_CHAR_ENABLED  0x02
  98
  99 struct usbtmc_blacklist {
 100         uint16_t vid;
 101         uint16_t pid;
 102 };
 103
 104 static struct usbtmc_blacklist blacklist_remote[] = {
 105         /* Rigol DS1000 series publishes RL1 support, but doesn't support it. */
 106         { 0x1ab1, 0x0588 },
 107         ALL_ZERO
 108 };
 109
 110 static GSList *scpi_usbtmc_libusb_scan(struct drv_context *drvc)
 111 {
 112         struct libusb_device **devlist;
 113         struct libusb_device_descriptor des;
 114         struct libusb_config_descriptor *confdes;
 115         const struct libusb_interface_descriptor *intfdes;
 116         GSList *resources = NULL;
 117         int confidx, intfidx, ret, i;
 118         char *res;
 119
 120         ret = libusb_get_device_list(drvc->sr_ctx->libusb_ctx, &devlist);
 121         if (ret < 0) {
 122                 sr_err("Failed to get device list: %s.",
 123                        libusb_error_name(ret));
 124                 return NULL;
 125         }
 126         for (i = 0; devlist[i]; i++) {
 127                 libusb_get_device_descriptor(devlist[i], &des);
 128
 129                 for (confidx = 0; confidx < des.bNumConfigurations; confidx++) {
 130                         if ((ret = libusb_get_config_descriptor(devlist[i], confidx, &confdes)) < 0) {
 131                                 sr_dbg("Failed to get configuration descriptor: %s, "
 132                                        "ignoring device.", libusb_error_name(ret));
 133                                 break;
 134                         }
 135                         for (intfidx = 0; intfidx < confdes->bNumInterfaces; intfidx++) {
 136                                 intfdes = confdes->interface[intfidx].altsetting;
 137                                 if (intfdes->bInterfaceClass    != LIBUSB_CLASS_APPLICATION ||
 138                                     intfdes->bInterfaceSubClass != SUBCLASS_USBTMC          ||
 139                                     intfdes->bInterfaceProtocol != USBTMC_USB488)
 140                                         continue;
 141                                 sr_dbg("Found USBTMC device (VID:PID = %04x:%04x, "
 142                                        "bus.address = %d.%d).", des.idVendor, des.idProduct,
 143                                        libusb_get_bus_number(devlist[i]),
 144                                        libusb_get_device_address(devlist[i]));
 145                                 res = g_strdup_printf("usbtmc/%d.%d",
 146                                                       libusb_get_bus_number(devlist[i]),
 147                                                       libusb_get_device_address(devlist[i]));
 148                                 resources = g_slist_append(resources, res);
 149                         }
 150                         libusb_free_config_descriptor(confdes);
 151                 }
 152         }
 153         libusb_free_device_list(devlist, 1);
 154
 155         sr_dbg("Found %d device(s).", g_slist_length(resources));
 156
 157         return resources;
 158 }
 159
 160 static int scpi_usbtmc_libusb_dev_inst_new(void *priv, struct drv_context *drvc,
 161                 const char *resource, char **params, const char *serialcomm)
 162 {
 163         struct scpi_usbtmc_libusb *uscpi = priv;
 164         GSList *devices;
 165
 166         (void)resource;
 167         (void)serialcomm;
 168
 169         if (!params || !params[1]) {
 170                 sr_err("Invalid parameters.");
 171                 return SR_ERR;
 172         }
 173
 174         uscpi->ctx = drvc->sr_ctx;
 175         devices = sr_usb_find(uscpi->ctx->libusb_ctx, params[1]);
 176         if (g_slist_length(devices) != 1) {
 177                 sr_err("Failed to find USB device '%s'.", params[1]);
 178                 g_slist_free_full(devices, (GDestroyNotify)sr_usb_dev_inst_free);
 179                 return SR_ERR;
 180         }
 181         uscpi->usb = devices->data;
 182         g_slist_free(devices);
 183
 184         return SR_OK;
 185 }
 186
 187 static int check_usbtmc_blacklist(struct usbtmc_blacklist *blacklist,
 188                 uint16_t vid, uint16_t pid)
 189 {
 190         int i;
 191
 192         for (i = 0; blacklist[i].vid; i++) {
 193                 if (blacklist[i].vid == vid && blacklist[i].pid == pid)
 194                         return TRUE;
 195         }
 196
 197         return FALSE;
 198 }
 199
 200 static int scpi_usbtmc_remote(struct scpi_usbtmc_libusb *uscpi)
 201 {
 202         struct sr_usb_dev_inst *usb = uscpi->usb;
 203         struct libusb_device *dev;
 204         struct libusb_device_descriptor des;
 205         int ret;
 206         uint8_t status;
 207
 208         if (!(uscpi->usb488_dev_cap & USB488_DEV_CAP_RL1))
 209                 return SR_OK;
 210
 211         dev = libusb_get_device(usb->devhdl);
 212         libusb_get_device_descriptor(dev, &des);
 213         if (check_usbtmc_blacklist(blacklist_remote, des.idVendor, des.idProduct))
 214                 return SR_OK;
 215
 216         sr_dbg("Locking out local control.");
 217         ret = libusb_control_transfer(usb->devhdl,
 218                         LIBUSB_ENDPOINT_IN         |
 219                         LIBUSB_REQUEST_TYPE_CLASS  |
 220                         LIBUSB_RECIPIENT_INTERFACE,
 221                         REN_CONTROL, 1,
 222                         uscpi->interface,
 223                         &status, 1,
 224                         TRANSFER_TIMEOUT);
 225         if (ret < 0 || status != USBTMC_STATUS_SUCCESS) {
 226                 if (ret < 0)
 227                         sr_dbg("Failed to enter REN state: %s.", libusb_error_name(ret));
 228                 else
 229                         sr_dbg("Failed to enter REN state: USBTMC status %d.", status);
 230                 return SR_ERR;
 231         }
 232
 233         ret = libusb_control_transfer(usb->devhdl,
 234                         LIBUSB_ENDPOINT_IN         |
 235                         LIBUSB_REQUEST_TYPE_CLASS  |
 236                         LIBUSB_RECIPIENT_INTERFACE,
 237                         LOCAL_LOCKOUT, 1,
 238                         uscpi->interface,
 239                         &status, 1,
 240                         TRANSFER_TIMEOUT);
 241         if (ret < 0 || status != USBTMC_STATUS_SUCCESS) {
 242                 if (ret < 0)
 243                         sr_dbg("Failed to enter local lockout state: %s.",
 244                                         libusb_error_name(ret));
 245                 else
 246                         sr_dbg("Failed to enter local lockout state: USBTMC "
 247                                         "status %d.", status);
 248                 return SR_ERR;
 249         }
 250
 251         return SR_OK;
 252 }
 253
 254 static void scpi_usbtmc_local(struct scpi_usbtmc_libusb *uscpi)
 255 {
 256         struct sr_usb_dev_inst *usb = uscpi->usb;
 257         struct libusb_device *dev;
 258         struct libusb_device_descriptor des;
 259         int ret;
 260         uint8_t status;
 261
 262         if (!(uscpi->usb488_dev_cap & USB488_DEV_CAP_RL1))
 263                 return;
 264
 265         dev = libusb_get_device(usb->devhdl);
 266         libusb_get_device_descriptor(dev, &des);
 267         if (check_usbtmc_blacklist(blacklist_remote, des.idVendor, des.idProduct))
 268                 return;
 269
 270         sr_dbg("Returning local control.");
 271         ret = libusb_control_transfer(usb->devhdl,
 272                         LIBUSB_ENDPOINT_IN         |
 273                         LIBUSB_REQUEST_TYPE_CLASS  |
 274                         LIBUSB_RECIPIENT_INTERFACE,
 275                         GO_TO_LOCAL, 1,
 276                         uscpi->interface,
 277                         &status, 1,
 278                         TRANSFER_TIMEOUT);
 279         if (ret < 0 || status != USBTMC_STATUS_SUCCESS) {
 280                 if (ret < 0)
 281                         sr_dbg("Failed to clear local lockout state: %s.",
 282                                         libusb_error_name(ret));
 283                 else
 284                         sr_dbg("Failed to clear local lockout state: USBTMC "
 285                                         "status %d.", status);
 286         }
 287
 288         return;
 289 }
 290
 291 static int scpi_usbtmc_libusb_open(struct sr_scpi_dev_inst *scpi)
 292 {
 293         struct scpi_usbtmc_libusb *uscpi = scpi->priv;
 294         struct sr_usb_dev_inst *usb = uscpi->usb;
 295         struct libusb_device *dev;
 296         struct libusb_device_descriptor des;
 297         struct libusb_config_descriptor *confdes;
 298         const struct libusb_interface_descriptor *intfdes;
 299         const struct libusb_endpoint_descriptor *ep;
 300         int confidx, intfidx, epidx, config = 0;
 301         uint8_t capabilities[24];
 302         int ret, found = 0;
 303
 304         if (usb->devhdl)
 305                 return SR_OK;
 306
 307         if (sr_usb_open(uscpi->ctx->libusb_ctx, usb) != SR_OK)
 308                 return SR_ERR;
 309
 310         dev = libusb_get_device(usb->devhdl);
 311         libusb_get_device_descriptor(dev, &des);
 312
 313         for (confidx = 0; confidx < des.bNumConfigurations; confidx++) {
 314                 if ((ret = libusb_get_config_descriptor(dev, confidx, &confdes)) < 0) {
 315                         sr_dbg("Failed to get configuration descriptor: %s, "
 316                                "ignoring device.", libusb_error_name(ret));
 317                         continue;
 318                 }
 319                 for (intfidx = 0; intfidx < confdes->bNumInterfaces; intfidx++) {
 320                         intfdes = confdes->interface[intfidx].altsetting;
 321                         if (intfdes->bInterfaceClass    != LIBUSB_CLASS_APPLICATION ||
 322                             intfdes->bInterfaceSubClass != SUBCLASS_USBTMC          ||
 323                             intfdes->bInterfaceProtocol != USBTMC_USB488)
 324                                 continue;
 325                         uscpi->interface = intfdes->bInterfaceNumber;
 326                         config = confdes->bConfigurationValue;
 327                         sr_dbg("Interface %d configuration %d.", uscpi->interface, config);
 328                         for (epidx = 0; epidx < intfdes->bNumEndpoints; epidx++) {
 329                                 ep = &intfdes->endpoint[epidx];
 330                                 if (ep->bmAttributes == LIBUSB_TRANSFER_TYPE_BULK &&
 331                                     !(ep->bEndpointAddress & (LIBUSB_ENDPOINT_DIR_MASK))) {
 332                                         uscpi->bulk_out_ep = ep->bEndpointAddress;
 333                                         sr_dbg("Bulk OUT EP %d", uscpi->bulk_out_ep);
 334                                 }
 335                                 if (ep->bmAttributes == LIBUSB_TRANSFER_TYPE_BULK &&
 336                                     ep->bEndpointAddress & (LIBUSB_ENDPOINT_DIR_MASK)) {
 337                                         uscpi->bulk_in_ep = ep->bEndpointAddress;
 338                                         sr_dbg("Bulk IN EP %d", uscpi->bulk_in_ep & 0x7f);
 339                                 }
 340                                 if (ep->bmAttributes == LIBUSB_TRANSFER_TYPE_INTERRUPT &&
 341                                     ep->bEndpointAddress & (LIBUSB_ENDPOINT_DIR_MASK)) {
 342                                         uscpi->interrupt_ep = ep->bEndpointAddress;
 343                                         sr_dbg("Interrupt EP %d", uscpi->interrupt_ep & 0x7f);
 344                                 }
 345                         }
 346                         found = 1;
 347                 }
 348                 libusb_free_config_descriptor(confdes);
 349                 if (found)
 350                         break;
 351         }
 352
 353         if (!found) {
 354                 sr_err("Failed to find USBTMC interface.");
 355                 return SR_ERR;
 356         }
 357
 358         if (libusb_kernel_driver_active(usb->devhdl, uscpi->interface) == 1) {
 359                 if ((ret = libusb_detach_kernel_driver(usb->devhdl,
 360                                                        uscpi->interface)) < 0) {
 361                         sr_err("Failed to detach kernel driver: %s.",
 362                                libusb_error_name(ret));
 363                         return SR_ERR;
 364                 }
 365                 uscpi->detached_kernel_driver = 1;
 366         }
 367
 368         if ((ret = libusb_set_configuration(usb->devhdl, config)) < 0) {
 369                 sr_err("Failed to set configuration: %s.",
 370                        libusb_error_name(ret));
 371                 return SR_ERR;
 372         }
 373
 374         if ((ret = libusb_claim_interface(usb->devhdl, uscpi->interface)) < 0) {
 375                 sr_err("Failed to claim interface: %s.",
 376                        libusb_error_name(ret));
 377                 return SR_ERR;
 378         }
 379
 380         /* Get capabilities. */
 381         ret = libusb_control_transfer(usb->devhdl,
 382                                       LIBUSB_ENDPOINT_IN         |
 383                                       LIBUSB_REQUEST_TYPE_CLASS  |
 384                                       LIBUSB_RECIPIENT_INTERFACE,
 385                                       GET_CAPABILITIES, 0,
 386                                       uscpi->interface,
 387                                       capabilities, sizeof(capabilities),
 388                                       TRANSFER_TIMEOUT);
 389         if (ret == sizeof(capabilities)) {
 390                 uscpi->usbtmc_int_cap = capabilities[ 4];
 391                 uscpi->usbtmc_dev_cap = capabilities[ 5];
 392                 uscpi->usb488_dev_cap = capabilities[15];
 393         }
 394         sr_dbg("Device capabilities: %s%s%s%s%s, %s, %s",
 395                uscpi->usb488_dev_cap & USB488_DEV_CAP_SCPI       ? "SCPI, "    : "",
 396                uscpi->usbtmc_dev_cap & USBTMC_DEV_CAP_TERMCHAR   ? "TermChar, ": "",
 397                uscpi->usbtmc_int_cap & USBTMC_INT_CAP_LISTEN_ONLY? "L3, " :
 398                uscpi->usbtmc_int_cap & USBTMC_INT_CAP_TALK_ONLY  ? ""     : "L4, ",
 399                uscpi->usbtmc_int_cap & USBTMC_INT_CAP_TALK_ONLY  ? "T5, " :
 400                uscpi->usbtmc_int_cap & USBTMC_INT_CAP_LISTEN_ONLY? ""     : "T6, ",
 401                uscpi->usb488_dev_cap & USB488_DEV_CAP_SR1        ? "SR1"  : "SR0",
 402                uscpi->usb488_dev_cap & USB488_DEV_CAP_RL1        ? "RL1"  : "RL0",
 403                uscpi->usb488_dev_cap & USB488_DEV_CAP_DT1        ? "DT1"  : "DT0");
 404
 405         scpi_usbtmc_remote(uscpi);
 406
 407         return SR_OK;
 408 }
 409
 410 static int scpi_usbtmc_libusb_source_add(struct sr_session *session,
 411                 void *priv, int events, int timeout, sr_receive_data_callback cb,
 412                 void *cb_data)
 413 {
 414         struct scpi_usbtmc_libusb *uscpi = priv;
 415         (void)events;
 416         return usb_source_add(session, uscpi->ctx, timeout, cb, cb_data);
 417 }
 418
 419 static int scpi_usbtmc_libusb_source_remove(struct sr_session *session,
 420                 void *priv)
 421 {
 422         struct scpi_usbtmc_libusb *uscpi = priv;
 423         return usb_source_remove(session, uscpi->ctx);
 424 }
 425
 426 static void usbtmc_bulk_out_header_write(void *header, uint8_t MsgID,
 427                                          uint8_t bTag,
 428                                          uint32_t TransferSize,
 429                                          uint8_t bmTransferAttributes,
 430                                          char TermChar)
 431 {
 432           W8(header+ 0, MsgID);
 433           W8(header+ 1, bTag);
 434           W8(header+ 2, ~bTag);
 435           W8(header+ 3, 0);
 436         WL32(header+ 4, TransferSize);
 437           W8(header+ 8, bmTransferAttributes);
 438           W8(header+ 9, TermChar);
 439         WL16(header+10, 0);
 440 }
 441
 442 static int usbtmc_bulk_in_header_read(void *header, uint8_t MsgID,
 443                                       unsigned char bTag,
 444                                       int32_t *TransferSize,
 445                                       uint8_t *bmTransferAttributes)
 446 {
 447         if (R8(header+0) != MsgID ||
 448             R8(header+1) != bTag  ||
 449             R8(header+2) != (unsigned char)~bTag)
 450                 return SR_ERR;
 451         if (TransferSize)
 452                 *TransferSize = RL32(header+4);
 453         if (bmTransferAttributes)
 454                 *bmTransferAttributes = R8(header+8);
 455         return SR_OK;
 456 }
 457
 458 static int scpi_usbtmc_bulkout(struct scpi_usbtmc_libusb *uscpi,
 459                                uint8_t msg_id, const void *data, int32_t size,
 460                                uint8_t transfer_attributes)
 461 {
 462         struct sr_usb_dev_inst *usb = uscpi->usb;
 463         int padded_size, ret, transferred;
 464
 465         if (data && size+USBTMC_BULK_HEADER_SIZE+3 > (int)sizeof(uscpi->buffer)) {
 466                 sr_err("USBTMC bulk out transfer is too big.");
 467                 return SR_ERR;
 468         }
 469
 470         uscpi->bTag++;
 471         uscpi->bTag += !uscpi->bTag;  /* bTag == 0 is invalid so avoid it. */
 472
 473         usbtmc_bulk_out_header_write(uscpi->buffer, msg_id, uscpi->bTag,
 474                                      size, transfer_attributes, 0);
 475         if (data)
 476                 memcpy(uscpi->buffer+USBTMC_BULK_HEADER_SIZE, data, size);
 477         else
 478                 size = 0;
 479         size += USBTMC_BULK_HEADER_SIZE;
 480         padded_size = (size + 3) & ~0x3;
 481         memset(uscpi->buffer+size, 0, padded_size - size);
 482
 483         ret = libusb_bulk_transfer(usb->devhdl, uscpi->bulk_out_ep,
 484                                    uscpi->buffer, padded_size, &transferred,
 485                                    TRANSFER_TIMEOUT);
 486         if (ret < 0) {
 487                 sr_err("USBTMC bulk out transfer error: %s.",
 488                        libusb_error_name(ret));
 489                 return SR_ERR;
 490         }
 491
 492         if (transferred < padded_size) {
 493                 sr_dbg("USBTMC bulk out partial transfer (%d/%d bytes).",
 494                        transferred, padded_size);
 495                 return SR_ERR;
 496         }
 497
 498         return transferred - USBTMC_BULK_HEADER_SIZE;
 499 }
 500
 501 static int scpi_usbtmc_bulkin_start(struct scpi_usbtmc_libusb *uscpi,
 502                                     uint8_t msg_id, void *data, int32_t size,
 503                                     uint8_t *transfer_attributes)
 504 {
 505         struct sr_usb_dev_inst *usb = uscpi->usb;
 506         int ret, transferred, message_size;
 507
 508         ret = libusb_bulk_transfer(usb->devhdl, uscpi->bulk_in_ep, data, size,
 509                                    &transferred, TRANSFER_TIMEOUT);
 510         if (ret < 0) {
 511                 sr_err("USBTMC bulk in transfer error: %s.",
 512                        libusb_error_name(ret));
 513                 return SR_ERR;
 514         }
 515
 516         if (usbtmc_bulk_in_header_read(data, msg_id, uscpi->bTag, &message_size,
 517                                        transfer_attributes) != SR_OK) {
 518                 sr_err("USBTMC invalid bulk in header.");
 519                 return SR_ERR;
 520         }
 521
 522         message_size += USBTMC_BULK_HEADER_SIZE;
 523         uscpi->response_length = MIN(transferred, message_size);
 524         uscpi->response_bytes_read = USBTMC_BULK_HEADER_SIZE;
 525         uscpi->remaining_length = message_size - uscpi->response_length;
 526
 527         return transferred - USBTMC_BULK_HEADER_SIZE;
 528 }
 529
 530 static int scpi_usbtmc_bulkin_continue(struct scpi_usbtmc_libusb *uscpi,
 531                                        void *data, int size)
 532 {
 533         struct sr_usb_dev_inst *usb = uscpi->usb;
 534         int ret, transferred;
 535
 536         ret = libusb_bulk_transfer(usb->devhdl, uscpi->bulk_in_ep, data, size,
 537                                    &transferred, TRANSFER_TIMEOUT);
 538         if (ret < 0) {
 539                 sr_err("USBTMC bulk in transfer error: %s.",
 540                        libusb_error_name(ret));
 541                 return SR_ERR;
 542         }
 543
 544         uscpi->response_length = MIN(transferred, uscpi->remaining_length);
 545         uscpi->response_bytes_read = 0;
 546         uscpi->remaining_length -= uscpi->response_length;
 547
 548         return transferred;
 549 }
 550
 551 static int scpi_usbtmc_libusb_send(void *priv, const char *command)
 552 {
 553         struct scpi_usbtmc_libusb *uscpi = priv;
 554
 555         if (scpi_usbtmc_bulkout(uscpi, DEV_DEP_MSG_OUT,
 556                                 command, strlen(command), EOM) <= 0)
 557                 return SR_ERR;
 558
 559         sr_spew("Successfully sent SCPI command: '%s'.", command);
 560
 561         return SR_OK;
 562 }
 563
 564 static int scpi_usbtmc_libusb_read_begin(void *priv)
 565 {
 566         struct scpi_usbtmc_libusb *uscpi = priv;
 567
 568         uscpi->remaining_length = 0;
 569
 570         if (scpi_usbtmc_bulkout(uscpi, REQUEST_DEV_DEP_MSG_IN,
 571             NULL, INT32_MAX, 0) < 0)
 572                 return SR_ERR;
 573         if (scpi_usbtmc_bulkin_start(uscpi, DEV_DEP_MSG_IN,
 574                                      uscpi->buffer, sizeof(uscpi->buffer),
 575                                      &uscpi->bulkin_attributes) < 0)
 576                 return SR_ERR;
 577
 578         return SR_OK;
 579 }
 580
 581 static int scpi_usbtmc_libusb_read_data(void *priv, char *buf, int maxlen)
 582 {
 583         struct scpi_usbtmc_libusb *uscpi = priv;
 584         int read_length;
 585
 586         if (uscpi->response_bytes_read >= uscpi->response_length) {
 587                 if (uscpi->remaining_length > 0) {
 588                         if (scpi_usbtmc_bulkin_continue(uscpi, uscpi->buffer,
 589                                                         sizeof(uscpi->buffer)) <= 0)
 590                                 return SR_ERR;
 591                 } else {
 592                         if (uscpi->bulkin_attributes & EOM)
 593                                 return SR_ERR;
 594                         if (scpi_usbtmc_libusb_read_begin(uscpi) < 0)
 595                                 return SR_ERR;
 596                 }
 597         }
 598
 599         read_length = MIN(uscpi->response_length - uscpi->response_bytes_read, maxlen);
 600
 601         memcpy(buf, uscpi->buffer + uscpi->response_bytes_read, read_length);
 602
 603         uscpi->response_bytes_read += read_length;
 604
 605         return read_length;
 606 }
 607
 608 static int scpi_usbtmc_libusb_read_complete(void *priv)
 609 {
 610         struct scpi_usbtmc_libusb *uscpi = priv;
 611         return uscpi->response_bytes_read >= uscpi->response_length &&
 612                uscpi->remaining_length <= 0 &&
 613                uscpi->bulkin_attributes & EOM;
 614 }
 615
 616 static int scpi_usbtmc_libusb_close(struct sr_scpi_dev_inst *scpi)
 617 {
 618         struct scpi_usbtmc_libusb *uscpi = scpi->priv;
 619         struct sr_usb_dev_inst *usb = uscpi->usb;
 620         struct libusb_device *dev;
 621         struct libusb_device_descriptor des;
 622         int ret;
 623
 624         if (!usb->devhdl)
 625                 return SR_ERR;
 626
 627         dev = libusb_get_device(usb->devhdl);
 628         libusb_get_device_descriptor(dev, &des);
 629         if (des.idVendor == 0x1ab1 && des.idProduct == 0x0588
 630                         && scpi->firmware_version >= 24) {
 631                 /* Rigol DS1000 with firmware > 0.2.4 needs this. */
 632                 if ((ret = libusb_clear_halt(usb->devhdl, uscpi->bulk_in_ep)) < 0)
 633                         sr_err("Failed to clear halt/stall condition for EP %d: %s.",
 634                                uscpi->bulk_out_ep, libusb_error_name(ret));
 635                 if ((ret = libusb_clear_halt(usb->devhdl, uscpi->bulk_out_ep)) < 0)
 636                         sr_err("Failed to clear halt/stall condition for EP %d: %s.",
 637                                uscpi->bulk_out_ep, libusb_error_name(ret));
 638         }
 639
 640         scpi_usbtmc_local(uscpi);
 641
 642         if ((ret = libusb_release_interface(usb->devhdl, uscpi->interface)) < 0)
 643                 sr_err("Failed to release interface: %s.",
 644                        libusb_error_name(ret));
 645
 646         if (uscpi->detached_kernel_driver) {
 647                 if ((ret = libusb_attach_kernel_driver(usb->devhdl,
 648                                                 uscpi->interface)) < 0)
 649                         sr_err("Failed to re-attach kernel driver: %s.",
 650                                libusb_error_name(ret));
 651
 652                 uscpi->detached_kernel_driver = 0;
 653         }
 654         sr_usb_close(usb);
 655
 656         return SR_OK;
 657 }
 658
 659 static void scpi_usbtmc_libusb_free(void *priv)
 660 {
 661         struct scpi_usbtmc_libusb *uscpi = priv;
 662         sr_usb_dev_inst_free(uscpi->usb);
 663 }
 664
 665 SR_PRIV const struct sr_scpi_dev_inst scpi_usbtmc_libusb_dev = {
 666         .name          = "USBTMC",
 667         .prefix        = "usbtmc",
 668         .priv_size     = sizeof(struct scpi_usbtmc_libusb),
 669         .scan          = scpi_usbtmc_libusb_scan,
 670         .dev_inst_new  = scpi_usbtmc_libusb_dev_inst_new,
 671         .open          = scpi_usbtmc_libusb_open,
 672         .source_add    = scpi_usbtmc_libusb_source_add,
 673         .source_remove = scpi_usbtmc_libusb_source_remove,
 674         .send          = scpi_usbtmc_libusb_send,
 675         .read_begin    = scpi_usbtmc_libusb_read_begin,
 676         .read_data     = scpi_usbtmc_libusb_read_data,
 677         .read_complete = scpi_usbtmc_libusb_read_complete,
 678         .close         = scpi_usbtmc_libusb_close,
 679         .free          = scpi_usbtmc_libusb_free,
 680 };