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 /* Devices that publish RL1 support, but don't support it. */
 105 static struct usbtmc_blacklist blacklist_remote[] = {
 106         { 0x1ab1, 0x0588 }, /* Rigol DS1000 series */
 107         { 0x1ab1, 0x04b0 }, /* Rigol DS2000 series */
 108         { 0x1ab1, 0x04b1 }, /* Rigol DS4000 series */
 109         { 0x0957, 0x0588 }, /* Agilent DSO1000 series (rebadged Rigol DS1000) */
 110         { 0x0b21, 0xffff }, /* All Yokogawa devices */
 111         { 0xf4ec, 0xffff }, /* All Siglent SDS devices */
 112         ALL_ZERO
 113 };
 114
 115 /* Devices that shall get reset during open(). */
 116 static struct usbtmc_blacklist whitelist_usb_reset[] = {
 117         { 0xf4ec, 0xffff }, /* All Siglent SDS devices */
 118         ALL_ZERO
 119 };
 120
 121 static GSList *scpi_usbtmc_libusb_scan(struct drv_context *drvc)
 122 {
 123         struct libusb_device **devlist;
 124         struct libusb_device_descriptor des;
 125         struct libusb_config_descriptor *confdes;
 126         const struct libusb_interface_descriptor *intfdes;
 127         GSList *resources = NULL;
 128         int confidx, intfidx, ret, i;
 129         char *res;
 130
 131         ret = libusb_get_device_list(drvc->sr_ctx->libusb_ctx, &devlist);
 132         if (ret < 0) {
 133                 sr_err("Failed to get device list: %s.",
 134                        libusb_error_name(ret));
 135                 return NULL;
 136         }
 137         for (i = 0; devlist[i]; i++) {
 138                 libusb_get_device_descriptor(devlist[i], &des);
 139
 140                 for (confidx = 0; confidx < des.bNumConfigurations; confidx++) {
 141                         if ((ret = libusb_get_config_descriptor(devlist[i], confidx, &confdes)) < 0) {
 142                                 if (ret != LIBUSB_ERROR_NOT_FOUND)
 143                                         sr_dbg("Failed to get configuration descriptor: %s, "
 144                                                "ignoring device.", libusb_error_name(ret));
 145                                 break;
 146                         }
 147                         for (intfidx = 0; intfidx < confdes->bNumInterfaces; intfidx++) {
 148                                 intfdes = confdes->interface[intfidx].altsetting;
 149                                 if (intfdes->bInterfaceClass    != LIBUSB_CLASS_APPLICATION ||
 150                                     intfdes->bInterfaceSubClass != SUBCLASS_USBTMC          ||
 151                                     intfdes->bInterfaceProtocol != USBTMC_USB488)
 152                                         continue;
 153                                 sr_dbg("Found USBTMC device (VID:PID = %04x:%04x, "
 154                                        "bus.address = %d.%d).", des.idVendor, des.idProduct,
 155                                        libusb_get_bus_number(devlist[i]),
 156                                        libusb_get_device_address(devlist[i]));
 157                                 res = g_strdup_printf("usbtmc/%d.%d",
 158                                                       libusb_get_bus_number(devlist[i]),
 159                                                       libusb_get_device_address(devlist[i]));
 160                                 resources = g_slist_append(resources, res);
 161                         }
 162                         libusb_free_config_descriptor(confdes);
 163                 }
 164         }
 165         libusb_free_device_list(devlist, 1);
 166
 167         /* No log message for #devices found (caller will log that). */
 168
 169         return resources;
 170 }
 171
 172 static int scpi_usbtmc_libusb_dev_inst_new(void *priv, struct drv_context *drvc,
 173                 const char *resource, char **params, const char *serialcomm)
 174 {
 175         struct scpi_usbtmc_libusb *uscpi = priv;
 176         GSList *devices;
 177
 178         (void)resource;
 179         (void)serialcomm;
 180
 181         if (!params || !params[1]) {
 182                 sr_err("Invalid parameters.");
 183                 return SR_ERR;
 184         }
 185
 186         uscpi->ctx = drvc->sr_ctx;
 187         devices = sr_usb_find(uscpi->ctx->libusb_ctx, params[1]);
 188         if (g_slist_length(devices) != 1) {
 189                 sr_err("Failed to find USB device '%s'.", params[1]);
 190                 g_slist_free_full(devices, (GDestroyNotify)sr_usb_dev_inst_free);
 191                 return SR_ERR;
 192         }
 193         uscpi->usb = devices->data;
 194         g_slist_free(devices);
 195
 196         return SR_OK;
 197 }
 198
 199 static int check_usbtmc_blacklist(struct usbtmc_blacklist *blacklist,
 200                 uint16_t vid, uint16_t pid)
 201 {
 202         int i;
 203
 204         for (i = 0; blacklist[i].vid; i++) {
 205                 if ((blacklist[i].vid == vid && blacklist[i].pid == 0xFFFF) ||
 206                         (blacklist[i].vid == vid && blacklist[i].pid == pid))
 207                         return TRUE;
 208         }
 209
 210         return FALSE;
 211 }
 212
 213 static int scpi_usbtmc_remote(struct scpi_usbtmc_libusb *uscpi)
 214 {
 215         struct sr_usb_dev_inst *usb = uscpi->usb;
 216         struct libusb_device *dev;
 217         struct libusb_device_descriptor des;
 218         int ret;
 219         uint8_t status;
 220
 221         if (!(uscpi->usb488_dev_cap & USB488_DEV_CAP_RL1))
 222                 return SR_OK;
 223
 224         dev = libusb_get_device(usb->devhdl);
 225         libusb_get_device_descriptor(dev, &des);
 226         if (check_usbtmc_blacklist(blacklist_remote, des.idVendor, des.idProduct))
 227                 return SR_OK;
 228
 229         sr_dbg("Locking out local control.");
 230         ret = libusb_control_transfer(usb->devhdl, LIBUSB_ENDPOINT_IN |
 231                 LIBUSB_REQUEST_TYPE_CLASS | LIBUSB_RECIPIENT_INTERFACE,
 232                 REN_CONTROL, 1, uscpi->interface, &status, 1, TRANSFER_TIMEOUT);
 233         if (ret < 0 || status != USBTMC_STATUS_SUCCESS) {
 234                 if (ret < 0)
 235                         sr_dbg("Failed to enter REN state: %s.", libusb_error_name(ret));
 236                 else
 237                         sr_dbg("Failed to enter REN state: USBTMC status %d.", status);
 238                 return SR_ERR;
 239         }
 240
 241         ret = libusb_control_transfer(usb->devhdl, LIBUSB_ENDPOINT_IN |
 242                 LIBUSB_REQUEST_TYPE_CLASS | LIBUSB_RECIPIENT_INTERFACE,
 243                 LOCAL_LOCKOUT, 0, uscpi->interface, &status, 1,
 244                 TRANSFER_TIMEOUT);
 245         if (ret < 0 || status != USBTMC_STATUS_SUCCESS) {
 246                 if (ret < 0)
 247                         sr_dbg("Failed to enter local lockout state: %s.",
 248                                         libusb_error_name(ret));
 249                 else
 250                         sr_dbg("Failed to enter local lockout state: USBTMC "
 251                                         "status %d.", status);
 252                 return SR_ERR;
 253         }
 254
 255         return SR_OK;
 256 }
 257
 258 static void scpi_usbtmc_local(struct scpi_usbtmc_libusb *uscpi)
 259 {
 260         struct sr_usb_dev_inst *usb = uscpi->usb;
 261         struct libusb_device *dev;
 262         struct libusb_device_descriptor des;
 263         int ret;
 264         uint8_t status;
 265
 266         if (!(uscpi->usb488_dev_cap & USB488_DEV_CAP_RL1))
 267                 return;
 268
 269         dev = libusb_get_device(usb->devhdl);
 270         libusb_get_device_descriptor(dev, &des);
 271         if (check_usbtmc_blacklist(blacklist_remote, des.idVendor, des.idProduct))
 272                 return;
 273
 274         sr_dbg("Returning local control.");
 275         ret = libusb_control_transfer(usb->devhdl, LIBUSB_ENDPOINT_IN |
 276                 LIBUSB_REQUEST_TYPE_CLASS | LIBUSB_RECIPIENT_INTERFACE,
 277                 GO_TO_LOCAL, 0, uscpi->interface, &status, 1, TRANSFER_TIMEOUT);
 278         if (ret < 0 || status != USBTMC_STATUS_SUCCESS) {
 279                 if (ret < 0)
 280                         sr_dbg("Failed to clear local lockout state: %s.",
 281                                         libusb_error_name(ret));
 282                 else
 283                         sr_dbg("Failed to clear local lockout state: USBTMC "
 284                                         "status %d.", status);
 285         }
 286
 287         return;
 288 }
 289
 290 static int scpi_usbtmc_libusb_open(struct sr_scpi_dev_inst *scpi)
 291 {
 292         struct scpi_usbtmc_libusb *uscpi = scpi->priv;
 293         struct sr_usb_dev_inst *usb = uscpi->usb;
 294         struct libusb_device *dev;
 295         struct libusb_device_descriptor des;
 296         struct libusb_config_descriptor *confdes;
 297         const struct libusb_interface_descriptor *intfdes;
 298         const struct libusb_endpoint_descriptor *ep;
 299         int confidx, intfidx, epidx, config = 0, current_config;
 300         uint8_t capabilities[24];
 301         int ret, found = 0;
 302         int do_reset;
 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                         if (ret != LIBUSB_ERROR_NOT_FOUND)
 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                 }
 349                 libusb_free_config_descriptor(confdes);
 350                 if (found)
 351                         break;
 352         }
 353
 354         if (!found) {
 355                 sr_err("Failed to find USBTMC interface.");
 356                 return SR_ERR;
 357         }
 358
 359         if (libusb_kernel_driver_active(usb->devhdl, uscpi->interface) == 1) {
 360                 if ((ret = libusb_detach_kernel_driver(usb->devhdl,
 361                                                        uscpi->interface)) < 0) {
 362                         sr_err("Failed to detach kernel driver: %s.",
 363                                libusb_error_name(ret));
 364                         return SR_ERR;
 365                 }
 366                 uscpi->detached_kernel_driver = 1;
 367         }
 368
 369         if (libusb_get_configuration(usb->devhdl, &current_config) == 0
 370             && current_config != config) {
 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
 378         if ((ret = libusb_claim_interface(usb->devhdl, uscpi->interface)) < 0) {
 379                 sr_err("Failed to claim interface: %s.",
 380                        libusb_error_name(ret));
 381                 return SR_ERR;
 382         }
 383
 384         /* Optionally reset the USB device. */
 385         do_reset = check_usbtmc_blacklist(whitelist_usb_reset,
 386                 des.idVendor, des.idProduct);
 387         if (do_reset)
 388                 libusb_reset_device(usb->devhdl);
 389
 390         /* Get capabilities. */
 391         ret = libusb_control_transfer(usb->devhdl, LIBUSB_ENDPOINT_IN |
 392                 LIBUSB_REQUEST_TYPE_CLASS | LIBUSB_RECIPIENT_INTERFACE,
 393                 GET_CAPABILITIES, 0, uscpi->interface, capabilities,
 394                 sizeof(capabilities), TRANSFER_TIMEOUT);
 395         if (ret == sizeof(capabilities)) {
 396                 uscpi->usbtmc_int_cap = capabilities[ 4];
 397                 uscpi->usbtmc_dev_cap = capabilities[ 5];
 398                 uscpi->usb488_dev_cap = capabilities[15];
 399         }
 400         sr_dbg("Device capabilities: %s%s%s%s%s, %s, %s",
 401                uscpi->usb488_dev_cap & USB488_DEV_CAP_SCPI        ? "SCPI, "    : "",
 402                uscpi->usbtmc_dev_cap & USBTMC_DEV_CAP_TERMCHAR    ? "TermChar, ": "",
 403                uscpi->usbtmc_int_cap & USBTMC_INT_CAP_LISTEN_ONLY ? "L3, " :
 404                uscpi->usbtmc_int_cap & USBTMC_INT_CAP_TALK_ONLY   ? ""     : "L4, ",
 405                uscpi->usbtmc_int_cap & USBTMC_INT_CAP_TALK_ONLY   ? "T5, " :
 406                uscpi->usbtmc_int_cap & USBTMC_INT_CAP_LISTEN_ONLY ? ""     : "T6, ",
 407                uscpi->usb488_dev_cap & USB488_DEV_CAP_SR1         ? "SR1"  : "SR0",
 408                uscpi->usb488_dev_cap & USB488_DEV_CAP_RL1         ? "RL1"  : "RL0",
 409                uscpi->usb488_dev_cap & USB488_DEV_CAP_DT1         ? "DT1"  : "DT0");
 410
 411         scpi_usbtmc_remote(uscpi);
 412
 413         return SR_OK;
 414 }
 415
 416 static int scpi_usbtmc_libusb_source_add(struct sr_session *session,
 417                 void *priv, int events, int timeout, sr_receive_data_callback cb,
 418                 void *cb_data)
 419 {
 420         struct scpi_usbtmc_libusb *uscpi = priv;
 421         (void)events;
 422         return usb_source_add(session, uscpi->ctx, timeout, cb, cb_data);
 423 }
 424
 425 static int scpi_usbtmc_libusb_source_remove(struct sr_session *session,
 426                 void *priv)
 427 {
 428         struct scpi_usbtmc_libusb *uscpi = priv;
 429         return usb_source_remove(session, uscpi->ctx);
 430 }
 431
 432 static void usbtmc_bulk_out_header_write(void *header, uint8_t MsgID,
 433                                          uint8_t bTag,
 434                                          uint32_t TransferSize,
 435                                          uint8_t bmTransferAttributes,
 436                                          char TermChar)
 437 {
 438           W8(header +  0, MsgID);
 439           W8(header +  1, bTag);
 440           W8(header +  2, ~bTag);
 441           W8(header +  3, 0);
 442         WL32(header +  4, TransferSize);
 443           W8(header +  8, bmTransferAttributes);
 444           W8(header +  9, TermChar);
 445         WL16(header + 10, 0);
 446 }
 447
 448 static int usbtmc_bulk_in_header_read(void *header, uint8_t MsgID,
 449                                       unsigned char bTag,
 450                                       int32_t *TransferSize,
 451                                       uint8_t *bmTransferAttributes)
 452 {
 453         if (R8(header + 0) != MsgID ||
 454             R8(header + 1) != bTag  ||
 455             R8(header + 2) != (unsigned char)~bTag)
 456                 return SR_ERR;
 457         if (TransferSize)
 458                 *TransferSize = RL32(header + 4);
 459         if (bmTransferAttributes)
 460                 *bmTransferAttributes = R8(header + 8);
 461
 462         return SR_OK;
 463 }
 464
 465 static int scpi_usbtmc_bulkout(struct scpi_usbtmc_libusb *uscpi,
 466                                uint8_t msg_id, const void *data, int32_t size,
 467                                uint8_t transfer_attributes)
 468 {
 469         struct sr_usb_dev_inst *usb = uscpi->usb;
 470         int padded_size, ret, transferred;
 471
 472         if (data && (size + USBTMC_BULK_HEADER_SIZE + 3) > (int)sizeof(uscpi->buffer)) {
 473                 sr_err("USBTMC bulk out transfer is too big.");
 474                 return SR_ERR;
 475         }
 476
 477         uscpi->bTag++;
 478         uscpi->bTag += !uscpi->bTag; /* bTag == 0 is invalid so avoid it. */
 479
 480         usbtmc_bulk_out_header_write(uscpi->buffer, msg_id, uscpi->bTag,
 481                                      size, transfer_attributes, 0);
 482         if (data)
 483                 memcpy(uscpi->buffer + USBTMC_BULK_HEADER_SIZE, data, size);
 484         else
 485                 size = 0;
 486         size += USBTMC_BULK_HEADER_SIZE;
 487         padded_size = (size + 3) & ~0x3;
 488         memset(uscpi->buffer + size, 0, padded_size - size);
 489
 490         ret = libusb_bulk_transfer(usb->devhdl, uscpi->bulk_out_ep,
 491                                    uscpi->buffer, padded_size, &transferred,
 492                                    TRANSFER_TIMEOUT);
 493         if (ret < 0) {
 494                 sr_err("USBTMC bulk out transfer error: %s.",
 495                        libusb_error_name(ret));
 496                 return SR_ERR;
 497         }
 498
 499         if (transferred < padded_size) {
 500                 sr_dbg("USBTMC bulk out partial transfer (%d/%d bytes).",
 501                        transferred, padded_size);
 502                 return SR_ERR;
 503         }
 504
 505         return transferred - USBTMC_BULK_HEADER_SIZE;
 506 }
 507
 508 static int scpi_usbtmc_bulkin_start(struct scpi_usbtmc_libusb *uscpi,
 509                                     uint8_t msg_id, void *data, int32_t size,
 510                                     uint8_t *transfer_attributes)
 511 {
 512         struct sr_usb_dev_inst *usb = uscpi->usb;
 513         int ret, transferred, message_size;
 514
 515         ret = libusb_bulk_transfer(usb->devhdl, uscpi->bulk_in_ep, data, size,
 516                                    &transferred, TRANSFER_TIMEOUT);
 517         if (ret < 0) {
 518                 sr_err("USBTMC bulk in transfer error: %s.",
 519                        libusb_error_name(ret));
 520                 return SR_ERR;
 521         }
 522
 523         if (usbtmc_bulk_in_header_read(data, msg_id, uscpi->bTag, &message_size,
 524                                        transfer_attributes) != SR_OK) {
 525                 sr_err("USBTMC invalid bulk in header.");
 526                 return SR_ERR;
 527         }
 528
 529         message_size += USBTMC_BULK_HEADER_SIZE;
 530         uscpi->response_length = MIN(transferred, message_size);
 531         uscpi->response_bytes_read = USBTMC_BULK_HEADER_SIZE;
 532         uscpi->remaining_length = message_size - uscpi->response_length;
 533
 534         return transferred - USBTMC_BULK_HEADER_SIZE;
 535 }
 536
 537 static int scpi_usbtmc_bulkin_continue(struct scpi_usbtmc_libusb *uscpi,
 538                                        void *data, int size)
 539 {
 540         struct sr_usb_dev_inst *usb = uscpi->usb;
 541         int ret, transferred;
 542
 543         ret = libusb_bulk_transfer(usb->devhdl, uscpi->bulk_in_ep, data, size,
 544                                    &transferred, TRANSFER_TIMEOUT);
 545         if (ret < 0) {
 546                 sr_err("USBTMC bulk in transfer error: %s.",
 547                        libusb_error_name(ret));
 548                 return SR_ERR;
 549         }
 550
 551         uscpi->response_length = MIN(transferred, uscpi->remaining_length);
 552         uscpi->response_bytes_read = 0;
 553         uscpi->remaining_length -= uscpi->response_length;
 554
 555         return transferred;
 556 }
 557
 558 static int scpi_usbtmc_libusb_send(void *priv, const char *command)
 559 {
 560         struct scpi_usbtmc_libusb *uscpi = priv;
 561
 562         if (scpi_usbtmc_bulkout(uscpi, DEV_DEP_MSG_OUT,
 563                                 command, strlen(command), EOM) <= 0)
 564                 return SR_ERR;
 565
 566         sr_spew("Successfully sent SCPI command: '%s'.", command);
 567
 568         return SR_OK;
 569 }
 570
 571 static int scpi_usbtmc_libusb_read_begin(void *priv)
 572 {
 573         struct scpi_usbtmc_libusb *uscpi = priv;
 574
 575         uscpi->remaining_length = 0;
 576
 577         if (scpi_usbtmc_bulkout(uscpi, REQUEST_DEV_DEP_MSG_IN,
 578             NULL, INT32_MAX, 0) < 0)
 579                 return SR_ERR;
 580         if (scpi_usbtmc_bulkin_start(uscpi, DEV_DEP_MSG_IN,
 581                                      uscpi->buffer, sizeof(uscpi->buffer),
 582                                      &uscpi->bulkin_attributes) < 0)
 583                 return SR_ERR;
 584
 585         return SR_OK;
 586 }
 587
 588 static int scpi_usbtmc_libusb_read_data(void *priv, char *buf, int maxlen)
 589 {
 590         struct scpi_usbtmc_libusb *uscpi = priv;
 591         int read_length;
 592
 593         if (uscpi->response_bytes_read >= uscpi->response_length) {
 594                 if (uscpi->remaining_length > 0) {
 595                         if (scpi_usbtmc_bulkin_continue(uscpi, uscpi->buffer,
 596                                                         sizeof(uscpi->buffer)) <= 0)
 597                                 return SR_ERR;
 598                 } else {
 599                         if (uscpi->bulkin_attributes & EOM)
 600                                 return SR_ERR;
 601                         if (scpi_usbtmc_libusb_read_begin(uscpi) < 0)
 602                                 return SR_ERR;
 603                 }
 604         }
 605
 606         read_length = MIN(uscpi->response_length - uscpi->response_bytes_read, maxlen);
 607
 608         memcpy(buf, uscpi->buffer + uscpi->response_bytes_read, read_length);
 609
 610         uscpi->response_bytes_read += read_length;
 611
 612         return read_length;
 613 }
 614
 615 static int scpi_usbtmc_libusb_read_complete(void *priv)
 616 {
 617         struct scpi_usbtmc_libusb *uscpi = priv;
 618         return uscpi->response_bytes_read >= uscpi->response_length &&
 619                uscpi->remaining_length <= 0 &&
 620                uscpi->bulkin_attributes & EOM;
 621 }
 622
 623 static int scpi_usbtmc_libusb_close(struct sr_scpi_dev_inst *scpi)
 624 {
 625         struct scpi_usbtmc_libusb *uscpi = scpi->priv;
 626         struct sr_usb_dev_inst *usb = uscpi->usb;
 627         int ret;
 628
 629         if (!usb->devhdl)
 630                 return SR_ERR;
 631
 632         scpi_usbtmc_local(uscpi);
 633
 634         if ((ret = libusb_release_interface(usb->devhdl, uscpi->interface)) < 0)
 635                 sr_err("Failed to release interface: %s.",
 636                        libusb_error_name(ret));
 637
 638         if (uscpi->detached_kernel_driver) {
 639                 if ((ret = libusb_attach_kernel_driver(usb->devhdl,
 640                                                 uscpi->interface)) < 0)
 641                         sr_err("Failed to re-attach kernel driver: %s.",
 642                                libusb_error_name(ret));
 643
 644                 uscpi->detached_kernel_driver = 0;
 645         }
 646         sr_usb_close(usb);
 647
 648         return SR_OK;
 649 }
 650
 651 static void scpi_usbtmc_libusb_free(void *priv)
 652 {
 653         struct scpi_usbtmc_libusb *uscpi = priv;
 654         sr_usb_dev_inst_free(uscpi->usb);
 655 }
 656
 657 SR_PRIV const struct sr_scpi_dev_inst scpi_usbtmc_libusb_dev = {
 658         .name          = "USBTMC",
 659         .prefix        = "usbtmc",
 660         .priv_size     = sizeof(struct scpi_usbtmc_libusb),
 661         .scan          = scpi_usbtmc_libusb_scan,
 662         .dev_inst_new  = scpi_usbtmc_libusb_dev_inst_new,
 663         .open          = scpi_usbtmc_libusb_open,
 664         .source_add    = scpi_usbtmc_libusb_source_add,
 665         .source_remove = scpi_usbtmc_libusb_source_remove,
 666         .send          = scpi_usbtmc_libusb_send,
 667         .read_begin    = scpi_usbtmc_libusb_read_begin,
 668         .read_data     = scpi_usbtmc_libusb_read_data,
 669         .read_complete = scpi_usbtmc_libusb_read_complete,
 670         .close         = scpi_usbtmc_libusb_close,
 671         .free          = scpi_usbtmc_libusb_free,
 672 };