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 <inttypes.h>
  22 #include <string.h>
  23 #include <libsigrok/libsigrok.h>
  24 #include "libsigrok-internal.h"
  25 #include "scpi.h"
  26
  27 #define LOG_PREFIX "scpi_usbtmc"
  28
  29 #define MAX_TRANSFER_LENGTH 2048
  30 #define TRANSFER_TIMEOUT 1000
  31
  32 struct scpi_usbtmc_libusb {
  33         struct sr_context *ctx;
  34         struct sr_usb_dev_inst *usb;
  35         int detached_kernel_driver;
  36         uint8_t interface;
  37         uint8_t bulk_in_ep;
  38         uint8_t bulk_out_ep;
  39         uint8_t interrupt_ep;
  40         uint8_t usbtmc_int_cap;
  41         uint8_t usbtmc_dev_cap;
  42         uint8_t usb488_dev_cap;
  43         uint8_t bTag;
  44         uint8_t bulkin_attributes;
  45         uint8_t buffer[MAX_TRANSFER_LENGTH];
  46         int response_length;
  47         int response_bytes_read;
  48         int remaining_length;
  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 /* Devices that publish RL1 support, but don't support it. */
 106 static struct usbtmc_blacklist blacklist_remote[] = {
 107         { 0x1ab1, 0x0588 }, /* Rigol DS1000 series */
 108         { 0x1ab1, 0x04b0 }, /* Rigol DS2000 series */
 109         { 0x1ab1, 0x04b1 }, /* Rigol DS4000 series */
 110         { 0x0957, 0x0588 }, /* Agilent DSO1000 series (rebadged Rigol DS1000) */
 111         { 0x0b21, 0xffff }, /* All Yokogawa devices */
 112         { 0xf4ec, 0xffff }, /* All Siglent SDS devices */
 113         ALL_ZERO
 114 };
 115
 116 /* Devices that shall get reset during open(). */
 117 static struct usbtmc_blacklist whitelist_usb_reset[] = {
 118         { 0xf4ec, 0xffff }, /* All Siglent SDS devices */
 119         ALL_ZERO
 120 };
 121
 122 static GSList *scpi_usbtmc_libusb_scan(struct drv_context *drvc)
 123 {
 124         struct libusb_device **devlist;
 125         struct libusb_device_descriptor des;
 126         struct libusb_config_descriptor *confdes;
 127         const struct libusb_interface_descriptor *intfdes;
 128         GSList *resources = NULL;
 129         int confidx, intfidx, ret, i;
 130         char *res;
 131
 132         ret = libusb_get_device_list(drvc->sr_ctx->libusb_ctx, &devlist);
 133         if (ret < 0) {
 134                 sr_err("Failed to get device list: %s.",
 135                        libusb_error_name(ret));
 136                 return NULL;
 137         }
 138         for (i = 0; devlist[i]; i++) {
 139                 libusb_get_device_descriptor(devlist[i], &des);
 140
 141                 for (confidx = 0; confidx < des.bNumConfigurations; confidx++) {
 142                         if ((ret = libusb_get_config_descriptor(devlist[i], confidx, &confdes)) < 0) {
 143                                 if (ret != LIBUSB_ERROR_NOT_FOUND)
 144                                         sr_dbg("Failed to get configuration descriptor: %s, "
 145                                                "ignoring device.", libusb_error_name(ret));
 146                                 break;
 147                         }
 148                         for (intfidx = 0; intfidx < confdes->bNumInterfaces; intfidx++) {
 149                                 intfdes = confdes->interface[intfidx].altsetting;
 150                                 if (intfdes->bInterfaceClass    != LIBUSB_CLASS_APPLICATION ||
 151                                     intfdes->bInterfaceSubClass != SUBCLASS_USBTMC          ||
 152                                     intfdes->bInterfaceProtocol != USBTMC_USB488)
 153                                         continue;
 154                                 sr_dbg("Found USBTMC device (VID:PID = %04x:%04x, "
 155                                        "bus.address = %d.%d).", des.idVendor, des.idProduct,
 156                                        libusb_get_bus_number(devlist[i]),
 157                                        libusb_get_device_address(devlist[i]));
 158                                 res = g_strdup_printf("usbtmc/%d.%d",
 159                                                       libusb_get_bus_number(devlist[i]),
 160                                                       libusb_get_device_address(devlist[i]));
 161                                 resources = g_slist_append(resources, res);
 162                         }
 163                         libusb_free_config_descriptor(confdes);
 164                 }
 165         }
 166         libusb_free_device_list(devlist, 1);
 167
 168         /* No log message for #devices found (caller will log that). */
 169
 170         return resources;
 171 }
 172
 173 static int scpi_usbtmc_libusb_dev_inst_new(void *priv, struct drv_context *drvc,
 174                 const char *resource, char **params, const char *serialcomm)
 175 {
 176         struct scpi_usbtmc_libusb *uscpi = priv;
 177         GSList *devices;
 178
 179         (void)resource;
 180         (void)serialcomm;
 181
 182         if (!params || !params[1]) {
 183                 sr_err("Invalid parameters.");
 184                 return SR_ERR;
 185         }
 186
 187         uscpi->ctx = drvc->sr_ctx;
 188         devices = sr_usb_find(uscpi->ctx->libusb_ctx, params[1]);
 189         if (g_slist_length(devices) != 1) {
 190                 sr_err("Failed to find USB device '%s'.", params[1]);
 191                 g_slist_free_full(devices, (GDestroyNotify)sr_usb_dev_inst_free);
 192                 return SR_ERR;
 193         }
 194         uscpi->usb = devices->data;
 195         g_slist_free(devices);
 196
 197         return SR_OK;
 198 }
 199
 200 static int check_usbtmc_blacklist(struct usbtmc_blacklist *blacklist,
 201                 uint16_t vid, uint16_t pid)
 202 {
 203         int i;
 204
 205         for (i = 0; blacklist[i].vid; i++) {
 206                 if ((blacklist[i].vid == vid && blacklist[i].pid == 0xFFFF) ||
 207                         (blacklist[i].vid == vid && blacklist[i].pid == pid))
 208                         return TRUE;
 209         }
 210
 211         return FALSE;
 212 }
 213
 214 static int scpi_usbtmc_remote(struct scpi_usbtmc_libusb *uscpi)
 215 {
 216         struct sr_usb_dev_inst *usb = uscpi->usb;
 217         struct libusb_device *dev;
 218         struct libusb_device_descriptor des;
 219         int ret;
 220         uint8_t status;
 221
 222         if (!(uscpi->usb488_dev_cap & USB488_DEV_CAP_RL1))
 223                 return SR_OK;
 224
 225         dev = libusb_get_device(usb->devhdl);
 226         libusb_get_device_descriptor(dev, &des);
 227         if (check_usbtmc_blacklist(blacklist_remote, des.idVendor, des.idProduct))
 228                 return SR_OK;
 229
 230         sr_dbg("Locking out local control.");
 231         ret = libusb_control_transfer(usb->devhdl, LIBUSB_ENDPOINT_IN |
 232                 LIBUSB_REQUEST_TYPE_CLASS | LIBUSB_RECIPIENT_INTERFACE,
 233                 REN_CONTROL, 1, uscpi->interface, &status, 1, TRANSFER_TIMEOUT);
 234         if (ret < 0 || status != USBTMC_STATUS_SUCCESS) {
 235                 if (ret < 0)
 236                         sr_dbg("Failed to enter REN state: %s.", libusb_error_name(ret));
 237                 else
 238                         sr_dbg("Failed to enter REN state: USBTMC status %d.", status);
 239                 return SR_ERR;
 240         }
 241
 242         ret = libusb_control_transfer(usb->devhdl, LIBUSB_ENDPOINT_IN |
 243                 LIBUSB_REQUEST_TYPE_CLASS | LIBUSB_RECIPIENT_INTERFACE,
 244                 LOCAL_LOCKOUT, 0, uscpi->interface, &status, 1,
 245                 TRANSFER_TIMEOUT);
 246         if (ret < 0 || status != USBTMC_STATUS_SUCCESS) {
 247                 if (ret < 0)
 248                         sr_dbg("Failed to enter local lockout state: %s.",
 249                                         libusb_error_name(ret));
 250                 else
 251                         sr_dbg("Failed to enter local lockout state: USBTMC "
 252                                         "status %d.", status);
 253                 return SR_ERR;
 254         }
 255
 256         return SR_OK;
 257 }
 258
 259 static void scpi_usbtmc_local(struct scpi_usbtmc_libusb *uscpi)
 260 {
 261         struct sr_usb_dev_inst *usb = uscpi->usb;
 262         struct libusb_device *dev;
 263         struct libusb_device_descriptor des;
 264         int ret;
 265         uint8_t status;
 266
 267         if (!(uscpi->usb488_dev_cap & USB488_DEV_CAP_RL1))
 268                 return;
 269
 270         dev = libusb_get_device(usb->devhdl);
 271         libusb_get_device_descriptor(dev, &des);
 272         if (check_usbtmc_blacklist(blacklist_remote, des.idVendor, des.idProduct))
 273                 return;
 274
 275         sr_dbg("Returning local control.");
 276         ret = libusb_control_transfer(usb->devhdl, LIBUSB_ENDPOINT_IN |
 277                 LIBUSB_REQUEST_TYPE_CLASS | LIBUSB_RECIPIENT_INTERFACE,
 278                 GO_TO_LOCAL, 0, uscpi->interface, &status, 1, 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, current_config;
 301         uint8_t capabilities[24];
 302         int ret, found = 0;
 303         int do_reset;
 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                         if (ret != LIBUSB_ERROR_NOT_FOUND)
 317                                 sr_dbg("Failed to get configuration descriptor: %s, "
 318                                        "ignoring device.", libusb_error_name(ret));
 319                         continue;
 320                 }
 321                 for (intfidx = 0; intfidx < confdes->bNumInterfaces; intfidx++) {
 322                         intfdes = confdes->interface[intfidx].altsetting;
 323                         if (intfdes->bInterfaceClass    != LIBUSB_CLASS_APPLICATION ||
 324                             intfdes->bInterfaceSubClass != SUBCLASS_USBTMC ||
 325                             intfdes->bInterfaceProtocol != USBTMC_USB488)
 326                                 continue;
 327                         uscpi->interface = intfdes->bInterfaceNumber;
 328                         config = confdes->bConfigurationValue;
 329                         sr_dbg("Interface %d configuration %d.", uscpi->interface, config);
 330                         for (epidx = 0; epidx < intfdes->bNumEndpoints; epidx++) {
 331                                 ep = &intfdes->endpoint[epidx];
 332                                 if (ep->bmAttributes == LIBUSB_TRANSFER_TYPE_BULK &&
 333                                     !(ep->bEndpointAddress & (LIBUSB_ENDPOINT_DIR_MASK))) {
 334                                         uscpi->bulk_out_ep = ep->bEndpointAddress;
 335                                         sr_dbg("Bulk OUT EP %d", uscpi->bulk_out_ep);
 336                                 }
 337                                 if (ep->bmAttributes == LIBUSB_TRANSFER_TYPE_BULK &&
 338                                     ep->bEndpointAddress & (LIBUSB_ENDPOINT_DIR_MASK)) {
 339                                         uscpi->bulk_in_ep = ep->bEndpointAddress;
 340                                         sr_dbg("Bulk IN EP %d", uscpi->bulk_in_ep & 0x7f);
 341                                 }
 342                                 if (ep->bmAttributes == LIBUSB_TRANSFER_TYPE_INTERRUPT &&
 343                                     ep->bEndpointAddress & (LIBUSB_ENDPOINT_DIR_MASK)) {
 344                                         uscpi->interrupt_ep = ep->bEndpointAddress;
 345                                         sr_dbg("Interrupt EP %d", uscpi->interrupt_ep & 0x7f);
 346                                 }
 347                         }
 348                         found = 1;
 349                 }
 350                 libusb_free_config_descriptor(confdes);
 351                 if (found)
 352                         break;
 353         }
 354
 355         if (!found) {
 356                 sr_err("Failed to find USBTMC interface.");
 357                 return SR_ERR;
 358         }
 359
 360         if (libusb_kernel_driver_active(usb->devhdl, uscpi->interface) == 1) {
 361                 if ((ret = libusb_detach_kernel_driver(usb->devhdl,
 362                                                        uscpi->interface)) < 0) {
 363                         sr_err("Failed to detach kernel driver: %s.",
 364                                libusb_error_name(ret));
 365                         return SR_ERR;
 366                 }
 367                 uscpi->detached_kernel_driver = 1;
 368         }
 369
 370         if (libusb_get_configuration(usb->devhdl, &current_config) == 0
 371             && current_config != config) {
 372                 if ((ret = libusb_set_configuration(usb->devhdl, config)) < 0) {
 373                         sr_err("Failed to set configuration: %s.",
 374                                libusb_error_name(ret));
 375                         return SR_ERR;
 376                 }
 377         }
 378
 379         if ((ret = libusb_claim_interface(usb->devhdl, uscpi->interface)) < 0) {
 380                 sr_err("Failed to claim interface: %s.",
 381                        libusb_error_name(ret));
 382                 return SR_ERR;
 383         }
 384
 385         /* Optionally reset the USB device. */
 386         do_reset = check_usbtmc_blacklist(whitelist_usb_reset,
 387                 des.idVendor, des.idProduct);
 388         if (do_reset)
 389                 libusb_reset_device(usb->devhdl);
 390
 391         /* Get capabilities. */
 392         ret = libusb_control_transfer(usb->devhdl, LIBUSB_ENDPOINT_IN |
 393                 LIBUSB_REQUEST_TYPE_CLASS | LIBUSB_RECIPIENT_INTERFACE,
 394                 GET_CAPABILITIES, 0, uscpi->interface, capabilities,
 395                 sizeof(capabilities), TRANSFER_TIMEOUT);
 396         if (ret == sizeof(capabilities)) {
 397                 uscpi->usbtmc_int_cap = capabilities[ 4];
 398                 uscpi->usbtmc_dev_cap = capabilities[ 5];
 399                 uscpi->usb488_dev_cap = capabilities[15];
 400         }
 401         sr_dbg("Device capabilities: %s%s%s%s%s, %s, %s",
 402                uscpi->usb488_dev_cap & USB488_DEV_CAP_SCPI        ? "SCPI, "    : "",
 403                uscpi->usbtmc_dev_cap & USBTMC_DEV_CAP_TERMCHAR    ? "TermChar, ": "",
 404                uscpi->usbtmc_int_cap & USBTMC_INT_CAP_LISTEN_ONLY ? "L3, " :
 405                uscpi->usbtmc_int_cap & USBTMC_INT_CAP_TALK_ONLY   ? ""     : "L4, ",
 406                uscpi->usbtmc_int_cap & USBTMC_INT_CAP_TALK_ONLY   ? "T5, " :
 407                uscpi->usbtmc_int_cap & USBTMC_INT_CAP_LISTEN_ONLY ? ""     : "T6, ",
 408                uscpi->usb488_dev_cap & USB488_DEV_CAP_SR1         ? "SR1"  : "SR0",
 409                uscpi->usb488_dev_cap & USB488_DEV_CAP_RL1         ? "RL1"  : "RL0",
 410                uscpi->usb488_dev_cap & USB488_DEV_CAP_DT1         ? "DT1"  : "DT0");
 411
 412         scpi_usbtmc_remote(uscpi);
 413
 414         return SR_OK;
 415 }
 416
 417 static int scpi_usbtmc_libusb_connection_id(struct sr_scpi_dev_inst *scpi,
 418                 char **connection_id)
 419 {
 420         struct scpi_usbtmc_libusb *uscpi = scpi->priv;
 421         struct sr_usb_dev_inst *usb = uscpi->usb;
 422
 423         *connection_id = g_strdup_printf("%s/%" PRIu8 ".%" PRIu8 "",
 424                 scpi->prefix, usb->bus, usb->address);
 425
 426         return SR_OK;
 427 }
 428
 429 static int scpi_usbtmc_libusb_source_add(struct sr_session *session,
 430                 void *priv, int events, int timeout, sr_receive_data_callback cb,
 431                 void *cb_data)
 432 {
 433         struct scpi_usbtmc_libusb *uscpi = priv;
 434         (void)events;
 435         return usb_source_add(session, uscpi->ctx, timeout, cb, cb_data);
 436 }
 437
 438 static int scpi_usbtmc_libusb_source_remove(struct sr_session *session,
 439                 void *priv)
 440 {
 441         struct scpi_usbtmc_libusb *uscpi = priv;
 442         return usb_source_remove(session, uscpi->ctx);
 443 }
 444
 445 static void usbtmc_bulk_out_header_write(void *header, uint8_t MsgID,
 446                                          uint8_t bTag,
 447                                          uint32_t TransferSize,
 448                                          uint8_t bmTransferAttributes,
 449                                          char TermChar)
 450 {
 451           W8(header +  0, MsgID);
 452           W8(header +  1, bTag);
 453           W8(header +  2, ~bTag);
 454           W8(header +  3, 0);
 455         WL32(header +  4, TransferSize);
 456           W8(header +  8, bmTransferAttributes);
 457           W8(header +  9, TermChar);
 458         WL16(header + 10, 0);
 459 }
 460
 461 static int usbtmc_bulk_in_header_read(void *header, uint8_t MsgID,
 462                                       unsigned char bTag,
 463                                       int32_t *TransferSize,
 464                                       uint8_t *bmTransferAttributes)
 465 {
 466         if (R8(header + 0) != MsgID ||
 467             R8(header + 1) != bTag  ||
 468             R8(header + 2) != (unsigned char)~bTag)
 469                 return SR_ERR;
 470         if (TransferSize)
 471                 *TransferSize = RL32(header + 4);
 472         if (bmTransferAttributes)
 473                 *bmTransferAttributes = R8(header + 8);
 474
 475         return SR_OK;
 476 }
 477
 478 static int scpi_usbtmc_bulkout(struct scpi_usbtmc_libusb *uscpi,
 479                                uint8_t msg_id, const void *data, int32_t size,
 480                                uint8_t transfer_attributes)
 481 {
 482         struct sr_usb_dev_inst *usb = uscpi->usb;
 483         int padded_size, ret, transferred;
 484
 485         if (data && (size + USBTMC_BULK_HEADER_SIZE + 3) > (int)sizeof(uscpi->buffer)) {
 486                 sr_err("USBTMC bulk out transfer is too big.");
 487                 return SR_ERR;
 488         }
 489
 490         uscpi->bTag++;
 491         uscpi->bTag += !uscpi->bTag; /* bTag == 0 is invalid so avoid it. */
 492
 493         usbtmc_bulk_out_header_write(uscpi->buffer, msg_id, uscpi->bTag,
 494                                      size, transfer_attributes, 0);
 495         if (data)
 496                 memcpy(uscpi->buffer + USBTMC_BULK_HEADER_SIZE, data, size);
 497         else
 498                 size = 0;
 499         size += USBTMC_BULK_HEADER_SIZE;
 500         padded_size = (size + 3) & ~0x3;
 501         memset(uscpi->buffer + size, 0, padded_size - size);
 502
 503         ret = libusb_bulk_transfer(usb->devhdl, uscpi->bulk_out_ep,
 504                                    uscpi->buffer, padded_size, &transferred,
 505                                    TRANSFER_TIMEOUT);
 506         if (ret < 0) {
 507                 sr_err("USBTMC bulk out transfer error: %s.",
 508                        libusb_error_name(ret));
 509                 return SR_ERR;
 510         }
 511
 512         if (transferred < padded_size) {
 513                 sr_dbg("USBTMC bulk out partial transfer (%d/%d bytes).",
 514                        transferred, padded_size);
 515                 return SR_ERR;
 516         }
 517
 518         return transferred - USBTMC_BULK_HEADER_SIZE;
 519 }
 520
 521 static int scpi_usbtmc_bulkin_start(struct scpi_usbtmc_libusb *uscpi,
 522                                     uint8_t msg_id, void *data, int32_t size,
 523                                     uint8_t *transfer_attributes)
 524 {
 525         struct sr_usb_dev_inst *usb = uscpi->usb;
 526         int ret, transferred, message_size;
 527
 528         ret = libusb_bulk_transfer(usb->devhdl, uscpi->bulk_in_ep, data, size,
 529                                    &transferred, TRANSFER_TIMEOUT);
 530         if (ret < 0) {
 531                 sr_err("USBTMC bulk in transfer error: %s.",
 532                        libusb_error_name(ret));
 533                 return SR_ERR;
 534         }
 535
 536         if (usbtmc_bulk_in_header_read(data, msg_id, uscpi->bTag, &message_size,
 537                                        transfer_attributes) != SR_OK) {
 538                 sr_err("USBTMC invalid bulk in header.");
 539                 return SR_ERR;
 540         }
 541
 542         message_size += USBTMC_BULK_HEADER_SIZE;
 543         uscpi->response_length = MIN(transferred, message_size);
 544         uscpi->response_bytes_read = USBTMC_BULK_HEADER_SIZE;
 545         uscpi->remaining_length = message_size - uscpi->response_length;
 546
 547         return transferred - USBTMC_BULK_HEADER_SIZE;
 548 }
 549
 550 static int scpi_usbtmc_bulkin_continue(struct scpi_usbtmc_libusb *uscpi,
 551                                        void *data, int size)
 552 {
 553         struct sr_usb_dev_inst *usb = uscpi->usb;
 554         int ret, transferred;
 555
 556         ret = libusb_bulk_transfer(usb->devhdl, uscpi->bulk_in_ep, data, size,
 557                                    &transferred, TRANSFER_TIMEOUT);
 558         if (ret < 0) {
 559                 sr_err("USBTMC bulk in transfer error: %s.",
 560                        libusb_error_name(ret));
 561                 return SR_ERR;
 562         }
 563
 564         uscpi->response_length = MIN(transferred, uscpi->remaining_length);
 565         uscpi->response_bytes_read = 0;
 566         uscpi->remaining_length -= uscpi->response_length;
 567
 568         return transferred;
 569 }
 570
 571 static int scpi_usbtmc_libusb_send(void *priv, const char *command)
 572 {
 573         struct scpi_usbtmc_libusb *uscpi = priv;
 574
 575         if (scpi_usbtmc_bulkout(uscpi, DEV_DEP_MSG_OUT,
 576                                 command, strlen(command), EOM) <= 0)
 577                 return SR_ERR;
 578
 579         sr_spew("Successfully sent SCPI command: '%s'.", command);
 580
 581         return SR_OK;
 582 }
 583
 584 static int scpi_usbtmc_libusb_read_begin(void *priv)
 585 {
 586         struct scpi_usbtmc_libusb *uscpi = priv;
 587
 588         uscpi->remaining_length = 0;
 589
 590         if (scpi_usbtmc_bulkout(uscpi, REQUEST_DEV_DEP_MSG_IN,
 591             NULL, INT32_MAX, 0) < 0)
 592                 return SR_ERR;
 593         if (scpi_usbtmc_bulkin_start(uscpi, DEV_DEP_MSG_IN,
 594                                      uscpi->buffer, sizeof(uscpi->buffer),
 595                                      &uscpi->bulkin_attributes) < 0)
 596                 return SR_ERR;
 597
 598         return SR_OK;
 599 }
 600
 601 static int scpi_usbtmc_libusb_read_data(void *priv, char *buf, int maxlen)
 602 {
 603         struct scpi_usbtmc_libusb *uscpi = priv;
 604         int read_length;
 605
 606         if (uscpi->response_bytes_read >= uscpi->response_length) {
 607                 if (uscpi->remaining_length > 0) {
 608                         if (scpi_usbtmc_bulkin_continue(uscpi, uscpi->buffer,
 609                                                         sizeof(uscpi->buffer)) <= 0)
 610                                 return SR_ERR;
 611                 } else {
 612                         if (uscpi->bulkin_attributes & EOM)
 613                                 return SR_ERR;
 614                         if (scpi_usbtmc_libusb_read_begin(uscpi) < 0)
 615                                 return SR_ERR;
 616                 }
 617         }
 618
 619         read_length = MIN(uscpi->response_length - uscpi->response_bytes_read, maxlen);
 620
 621         memcpy(buf, uscpi->buffer + uscpi->response_bytes_read, read_length);
 622
 623         uscpi->response_bytes_read += read_length;
 624
 625         return read_length;
 626 }
 627
 628 static int scpi_usbtmc_libusb_read_complete(void *priv)
 629 {
 630         struct scpi_usbtmc_libusb *uscpi = priv;
 631         return uscpi->response_bytes_read >= uscpi->response_length &&
 632                uscpi->remaining_length <= 0 &&
 633                uscpi->bulkin_attributes & EOM;
 634 }
 635
 636 static int scpi_usbtmc_libusb_close(struct sr_scpi_dev_inst *scpi)
 637 {
 638         struct scpi_usbtmc_libusb *uscpi = scpi->priv;
 639         struct sr_usb_dev_inst *usb = uscpi->usb;
 640         int ret;
 641
 642         if (!usb->devhdl)
 643                 return SR_ERR;
 644
 645         scpi_usbtmc_local(uscpi);
 646
 647         if ((ret = libusb_release_interface(usb->devhdl, uscpi->interface)) < 0)
 648                 sr_err("Failed to release interface: %s.",
 649                        libusb_error_name(ret));
 650
 651         if (uscpi->detached_kernel_driver) {
 652                 if ((ret = libusb_attach_kernel_driver(usb->devhdl,
 653                                                 uscpi->interface)) < 0)
 654                         sr_err("Failed to re-attach kernel driver: %s.",
 655                                libusb_error_name(ret));
 656
 657                 uscpi->detached_kernel_driver = 0;
 658         }
 659         sr_usb_close(usb);
 660
 661         return SR_OK;
 662 }
 663
 664 static void scpi_usbtmc_libusb_free(void *priv)
 665 {
 666         struct scpi_usbtmc_libusb *uscpi = priv;
 667         sr_usb_dev_inst_free(uscpi->usb);
 668 }
 669
 670 SR_PRIV const struct sr_scpi_dev_inst scpi_usbtmc_libusb_dev = {
 671         .name          = "USBTMC",
 672         .prefix        = "usbtmc",
 673         .transport     = SCPI_TRANSPORT_USBTMC,
 674         .priv_size     = sizeof(struct scpi_usbtmc_libusb),
 675         .scan          = scpi_usbtmc_libusb_scan,
 676         .dev_inst_new  = scpi_usbtmc_libusb_dev_inst_new,
 677         .open          = scpi_usbtmc_libusb_open,
 678         .connection_id = scpi_usbtmc_libusb_connection_id,
 679         .source_add    = scpi_usbtmc_libusb_source_add,
 680         .source_remove = scpi_usbtmc_libusb_source_remove,
 681         .send          = scpi_usbtmc_libusb_send,
 682         .read_begin    = scpi_usbtmc_libusb_read_begin,
 683         .read_data     = scpi_usbtmc_libusb_read_data,
 684         .read_complete = scpi_usbtmc_libusb_read_complete,
 685         .close         = scpi_usbtmc_libusb_close,
 686         .free          = scpi_usbtmc_libusb_free,
 687 };