hardware/common/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 <string.h>
  21 #include "libsigrok.h"
  22 #include "libsigrok-internal.h"
  23
  24 #define LOG_PREFIX "scpi_usbtmc"
  25
  26 #define MAX_TRANSFER_LENGTH 2048
  27 #define TRANSFER_TIMEOUT 1000
  28
  29 struct scpi_usbtmc_libusb {
  30         struct sr_context *ctx;
  31         struct sr_usb_dev_inst *usb;
  32         int detached_kernel_driver;
  33         uint8_t interface;
  34         uint8_t bulk_in_ep;
  35         uint8_t bulk_out_ep;
  36         uint8_t interrupt_ep;
  37         uint8_t usbtmc_int_cap;
  38         uint8_t usbtmc_dev_cap;
  39         uint8_t usb488_dev_cap;
  40         uint8_t bTag;
  41         uint8_t bulkin_attributes;
  42         uint8_t buffer[MAX_TRANSFER_LENGTH];
  43         int response_length;
  44         int response_bytes_read;
  45         int remaining_length;
  46 };
  47
  48 /* Some USBTMC-specific enums, as defined in the USBTMC standard. */
  49 #define SUBCLASS_USBTMC  0x03
  50 #define USBTMC_USB488    0x01
  51
  52 enum {
  53         /* USBTMC control requests */
  54         INITIATE_ABORT_BULK_OUT     =   1,
  55         CHECK_ABORT_BULK_OUT_STATUS =   2,
  56         INITIATE_ABORT_BULK_IN      =   3,
  57         CHECK_ABORT_BULK_IN_STATUS  =   4,
  58         INITIATE_CLEAR              =   5,
  59         CHECK_CLEAR_STATUS          =   6,
  60         GET_CAPABILITIES            =   7,
  61         INDICATOR_PULSE             =  64,
  62
  63         /* USB488 control requests */
  64         READ_STATUS_BYTE            = 128,
  65         REN_CONTROL                 = 160,
  66         GO_TO_LOCAL                 = 161,
  67         LOCAL_LOCKOUT               = 162,
  68 };
  69
  70 /* USBTMC capabilities */
  71 #define USBTMC_INT_CAP_LISTEN_ONLY 0x01
  72 #define USBTMC_INT_CAP_TALK_ONLY   0x02
  73 #define USBTMC_INT_CAP_INDICATOR   0x04
  74
  75 #define USBTMC_DEV_CAP_TERMCHAR    0x01
  76
  77 #define USB488_DEV_CAP_DT1         0x01
  78 #define USB488_DEV_CAP_RL1         0x02
  79 #define USB488_DEV_CAP_SR1         0x04
  80 #define USB488_DEV_CAP_SCPI        0x08
  81
  82 /* Bulk messages constants */
  83 #define USBTMC_BULK_HEADER_SIZE  12
  84
  85 /* Bulk MsgID values */
  86 #define DEV_DEP_MSG_OUT         1
  87 #define REQUEST_DEV_DEP_MSG_IN  2
  88 #define DEV_DEP_MSG_IN          2
  89
  90 /* bmTransferAttributes */
  91 #define EOM                0x01
  92 #define TERM_CHAR_ENABLED  0x02
  93
  94
  95 static GSList *scpi_usbtmc_libusb_scan(struct drv_context *drvc)
  96 {
  97         struct libusb_device **devlist;
  98         struct libusb_device_descriptor des;
  99         struct libusb_config_descriptor *confdes;
 100         const struct libusb_interface_descriptor *intfdes;
 101         GSList *resources = NULL;
 102         int confidx, intfidx, ret, i;
 103         char *res;
 104
 105         libusb_get_device_list(drvc->sr_ctx->libusb_ctx, &devlist);
 106         for (i = 0; devlist[i]; i++) {
 107                 if ((ret = libusb_get_device_descriptor(devlist[i], &des))) {
 108                         sr_err("Failed to get device descriptor: %s.",
 109                                libusb_error_name(ret));
 110                         continue;
 111                 }
 112
 113                 for (confidx = 0; confidx < des.bNumConfigurations; confidx++) {
 114                         if (libusb_get_config_descriptor(devlist[i], confidx, &confdes) != 0) {
 115                                 sr_err("Failed to get configuration descriptor.");
 116                                 break;
 117                         }
 118                         for (intfidx = 0; intfidx < confdes->bNumInterfaces; intfidx++) {
 119                                 intfdes = confdes->interface[intfidx].altsetting;
 120                                 if (intfdes->bInterfaceClass    != LIBUSB_CLASS_APPLICATION ||
 121                                     intfdes->bInterfaceSubClass != SUBCLASS_USBTMC          ||
 122                                     intfdes->bInterfaceProtocol != USBTMC_USB488)
 123                                         continue;
 124                                 sr_dbg("Found USBTMC device (VID:PID = %04x:%04x, "
 125                                        "bus.address = %d.%d).", des.idVendor, des.idProduct,
 126                                        libusb_get_bus_number(devlist[i]),
 127                                        libusb_get_device_address(devlist[i]));
 128                                 res = g_strdup_printf("usbtmc/%d.%d",
 129                                                       libusb_get_bus_number(devlist[i]),
 130                                                       libusb_get_device_address(devlist[i]));
 131                                 resources = g_slist_append(resources, res);
 132                         }
 133                         libusb_free_config_descriptor(confdes);
 134                 }
 135         }
 136         libusb_free_device_list(devlist, 1);
 137
 138         sr_dbg("Found %d device(s).", g_slist_length(resources));
 139
 140         return resources;
 141 }
 142
 143 static int scpi_usbtmc_libusb_dev_inst_new(void *priv, struct drv_context *drvc,
 144                 const char *resource, char **params, const char *serialcomm)
 145 {
 146         struct scpi_usbtmc_libusb *uscpi = priv;
 147         GSList *devices;
 148
 149         (void)resource;
 150         (void)serialcomm;
 151
 152         if (!params || !params[1]) {
 153                 sr_err("Invalid parameters.");
 154                 return SR_ERR;
 155         }
 156
 157         uscpi->ctx = drvc->sr_ctx;
 158         devices = sr_usb_find(uscpi->ctx->libusb_ctx, params[1]);
 159         if (g_slist_length(devices) != 1) {
 160                 sr_err("Failed to find USB device '%s'.", params[1]);
 161                 g_slist_free_full(devices, (GDestroyNotify)sr_usb_dev_inst_free);
 162                 return SR_ERR;
 163         }
 164         uscpi->usb = devices->data;
 165         g_slist_free(devices);
 166
 167         return SR_OK;
 168 }
 169
 170 static int scpi_usbtmc_libusb_open(void *priv)
 171 {
 172         struct scpi_usbtmc_libusb *uscpi = priv;
 173         struct sr_usb_dev_inst *usb = uscpi->usb;
 174         struct libusb_device *dev;
 175         struct libusb_device_descriptor des;
 176         struct libusb_config_descriptor *confdes;
 177         const struct libusb_interface_descriptor *intfdes;
 178         const struct libusb_endpoint_descriptor *ep;
 179         int confidx, intfidx, epidx, config = 0;
 180         uint8_t capabilities[24];
 181         int ret, found = 0;
 182
 183         if (usb->devhdl)
 184                 return SR_OK;
 185
 186         if (sr_usb_open(uscpi->ctx->libusb_ctx, usb) != SR_OK)
 187                 return SR_ERR;
 188
 189         dev = libusb_get_device(usb->devhdl);
 190         if ((ret = libusb_get_device_descriptor(dev, &des))) {
 191                 sr_err("Failed to get device descriptor: %s.",
 192                        libusb_error_name(ret));
 193                 return SR_ERR;
 194         }
 195
 196         for (confidx = 0; confidx < des.bNumConfigurations; confidx++) {
 197                 if (libusb_get_config_descriptor(dev, confidx, &confdes) != 0) {
 198                         sr_err("Failed to get configuration descriptor.");
 199                         continue;
 200                 }
 201                 for (intfidx = 0; intfidx < confdes->bNumInterfaces; intfidx++) {
 202                         intfdes = confdes->interface[intfidx].altsetting;
 203                         if (intfdes->bInterfaceClass    != LIBUSB_CLASS_APPLICATION ||
 204                             intfdes->bInterfaceSubClass != SUBCLASS_USBTMC          ||
 205                             intfdes->bInterfaceProtocol != USBTMC_USB488)
 206                                 continue;
 207                         uscpi->interface = intfdes->bInterfaceNumber;
 208                         sr_dbg("Interface %d", uscpi->interface);
 209                         config = confdes->bConfigurationValue;
 210                         sr_dbg("Configuration %d", config);
 211                         for (epidx = 0; epidx < intfdes->bNumEndpoints; epidx++) {
 212                                 ep = &intfdes->endpoint[epidx];
 213                                 if (ep->bmAttributes == LIBUSB_TRANSFER_TYPE_BULK &&
 214                                     !(ep->bEndpointAddress & (LIBUSB_ENDPOINT_DIR_MASK))) {
 215                                         uscpi->bulk_out_ep = ep->bEndpointAddress;
 216                                         sr_dbg("Bulk OUT EP %d", uscpi->bulk_out_ep);
 217                                 }
 218                                 if (ep->bmAttributes == LIBUSB_TRANSFER_TYPE_BULK &&
 219                                     ep->bEndpointAddress & (LIBUSB_ENDPOINT_DIR_MASK)) {
 220                                         uscpi->bulk_in_ep = ep->bEndpointAddress;
 221                                         sr_dbg("Bulk IN EP %d", uscpi->bulk_in_ep);
 222                                 }
 223                                 if (ep->bmAttributes == LIBUSB_TRANSFER_TYPE_INTERRUPT &&
 224                                     ep->bEndpointAddress & (LIBUSB_ENDPOINT_DIR_MASK)) {
 225                                         uscpi->interrupt_ep = ep->bEndpointAddress;
 226                                         sr_dbg("Interrupt EP %d", uscpi->interrupt_ep);
 227                                 }
 228                         }
 229                         found = 1;
 230                 }
 231                 libusb_free_config_descriptor(confdes);
 232                 if (found)
 233                         break;
 234         }
 235
 236         if (!found) {
 237                 sr_err("Failed to find USBTMC interface");
 238                 return SR_ERR;
 239         }
 240
 241         if (libusb_kernel_driver_active(usb->devhdl, uscpi->interface) == 1) {
 242                 if ((ret = libusb_detach_kernel_driver(usb->devhdl,
 243                                                        uscpi->interface)) < 0) {
 244                         sr_err("failed to detach kernel driver: %s",
 245                                         libusb_error_name(ret));
 246                         return SR_ERR;
 247                 }
 248                 uscpi->detached_kernel_driver = 1;
 249         }
 250
 251         if ((ret = libusb_set_configuration(usb->devhdl, config))) {
 252                 sr_err("Failed to set configuration: %s.", libusb_error_name(ret));
 253                 return SR_ERR;
 254         }
 255
 256         if ((ret = libusb_claim_interface(usb->devhdl, uscpi->interface))) {
 257                 sr_err("Failed to claim interface: %s.", libusb_error_name(ret));
 258                 return SR_ERR;
 259         }
 260
 261         libusb_clear_halt(usb->devhdl, uscpi->bulk_in_ep);
 262         libusb_clear_halt(usb->devhdl, uscpi->bulk_out_ep);
 263         libusb_clear_halt(usb->devhdl, uscpi->interrupt_ep);
 264
 265         /* get capabilities */
 266         ret = libusb_control_transfer(usb->devhdl,
 267                                       LIBUSB_ENDPOINT_IN         |
 268                                       LIBUSB_REQUEST_TYPE_CLASS  |
 269                                       LIBUSB_RECIPIENT_INTERFACE,
 270                                       GET_CAPABILITIES, 0,
 271                                       uscpi->interface,
 272                                       capabilities, sizeof(capabilities),
 273                                       TRANSFER_TIMEOUT);
 274         if (ret == sizeof(capabilities)) {
 275                 uscpi->usbtmc_int_cap = capabilities[ 4];
 276                 uscpi->usbtmc_dev_cap = capabilities[ 5];
 277                 uscpi->usb488_dev_cap = capabilities[15];
 278         }
 279         sr_dbg("device capabilities: %s%s%s%s%s, %s, %s",
 280                uscpi->usb488_dev_cap & USB488_DEV_CAP_SCPI       ? "SCPI, "    : "",
 281                uscpi->usbtmc_dev_cap & USBTMC_DEV_CAP_TERMCHAR   ? "TermChar, ": "",
 282                uscpi->usbtmc_int_cap & USBTMC_INT_CAP_LISTEN_ONLY? "L3, " :
 283                uscpi->usbtmc_int_cap & USBTMC_INT_CAP_TALK_ONLY  ? ""     : "L4, ",
 284                uscpi->usbtmc_int_cap & USBTMC_INT_CAP_TALK_ONLY  ? "T5, " :
 285                uscpi->usbtmc_int_cap & USBTMC_INT_CAP_LISTEN_ONLY? ""     : "T6, ",
 286                uscpi->usb488_dev_cap & USB488_DEV_CAP_SR1        ? "SR1"  : "SR0",
 287                uscpi->usb488_dev_cap & USB488_DEV_CAP_RL1        ? "RL1"  : "RL0",
 288                uscpi->usb488_dev_cap & USB488_DEV_CAP_DT1        ? "DT1"  : "DT0");
 289
 290         return SR_OK;
 291 }
 292
 293 static int scpi_usbtmc_libusb_source_add(void *priv, int events, int timeout,
 294                         sr_receive_data_callback_t cb, void *cb_data)
 295 {
 296         struct scpi_usbtmc_libusb *uscpi = priv;
 297         (void)events;
 298         return usb_source_add(uscpi->ctx, timeout, cb, cb_data);
 299 }
 300
 301 static int scpi_usbtmc_libusb_source_remove(void *priv)
 302 {
 303         struct scpi_usbtmc_libusb *uscpi = priv;
 304         return usb_source_remove(uscpi->ctx);
 305 }
 306
 307 static void usbtmc_bulk_out_header_write(void *header, uint8_t MsgID,
 308                                          uint8_t bTag,
 309                                          uint32_t TransferSize,
 310                                          uint8_t bmTransferAttributes,
 311                                          char TermChar)
 312 {
 313           W8(header+ 0, MsgID);
 314           W8(header+ 1, bTag);
 315           W8(header+ 2, ~bTag);
 316           W8(header+ 3, 0);
 317         WL32(header+ 4, TransferSize);
 318           W8(header+ 8, bmTransferAttributes);
 319           W8(header+ 9, TermChar);
 320         WL16(header+10, 0);
 321 }
 322
 323 static int usbtmc_bulk_in_header_read(void *header, uint8_t MsgID,
 324                                       unsigned char bTag,
 325                                       int32_t *TransferSize,
 326                                       uint8_t *bmTransferAttributes)
 327 {
 328         if (R8(header+0) != MsgID ||
 329             R8(header+1) != bTag  ||
 330             R8(header+2) != (unsigned char)~bTag)
 331                 return SR_ERR;
 332         if (TransferSize)
 333                 *TransferSize = RL32(header+4);
 334         if (bmTransferAttributes)
 335                 *bmTransferAttributes = R8(header+8);
 336         return SR_OK;
 337 }
 338
 339 static int scpi_usbtmc_bulkout(struct scpi_usbtmc_libusb *uscpi,
 340                                uint8_t msg_id, const void *data, int32_t size,
 341                                uint8_t transfer_attributes)
 342 {
 343         struct sr_usb_dev_inst *usb = uscpi->usb;
 344         int padded_size, ret, transferred;
 345
 346         if (data && size+USBTMC_BULK_HEADER_SIZE+3 > (int)sizeof(uscpi->buffer)) {
 347                 sr_err("USBTMC bulk out transfer too big");
 348                 return SR_ERR;
 349         }
 350
 351         uscpi->bTag++;
 352         uscpi->bTag += !uscpi->bTag;  /* bTag == 0 is invalid so avoid it */
 353
 354         usbtmc_bulk_out_header_write(uscpi->buffer, msg_id, uscpi->bTag,
 355                                      size, transfer_attributes, 0);
 356         if (data)
 357                 memcpy(uscpi->buffer+USBTMC_BULK_HEADER_SIZE, data, size);
 358         else
 359                 size = 0;
 360         size += USBTMC_BULK_HEADER_SIZE;
 361         padded_size = (size + 3) & ~0x3;
 362         memset(uscpi->buffer+size, 0, padded_size - size);
 363
 364         ret = libusb_bulk_transfer(usb->devhdl, uscpi->bulk_out_ep,
 365                                    uscpi->buffer, padded_size, &transferred,
 366                                    TRANSFER_TIMEOUT);
 367         if (ret) {
 368                 sr_err("USBTMC bulk out transfer error: %d", ret);
 369                 return SR_ERR;
 370         }
 371
 372         if (transferred < padded_size) {
 373                 sr_dbg("USBTMC bulkout partial transfer (%d/%d bytes)",
 374                        transferred, padded_size);
 375                 return SR_ERR;
 376         }
 377
 378         return transferred - USBTMC_BULK_HEADER_SIZE;
 379 }
 380
 381 static int scpi_usbtmc_bulkin_start(struct scpi_usbtmc_libusb *uscpi,
 382                                     uint8_t msg_id, void *data, int32_t size,
 383                                     uint8_t *transfer_attributes)
 384 {
 385         struct sr_usb_dev_inst *usb = uscpi->usb;
 386         int ret, transferred, message_size;
 387
 388         ret = libusb_bulk_transfer(usb->devhdl, uscpi->bulk_in_ep, data, size,
 389                                    &transferred, TRANSFER_TIMEOUT);
 390         if (ret) {
 391                 sr_err("USBTMC bulk in transfer error: %d", ret);
 392                 return SR_ERR;
 393         }
 394
 395         if (usbtmc_bulk_in_header_read(data, msg_id, uscpi->bTag, &message_size,
 396                                        transfer_attributes) != SR_OK) {
 397                 sr_err("USBTMC invalid bulk in header");
 398                 return SR_ERR;
 399         }
 400
 401         message_size += USBTMC_BULK_HEADER_SIZE;
 402         uscpi->response_length = MIN(transferred, message_size);
 403         uscpi->response_bytes_read = USBTMC_BULK_HEADER_SIZE;
 404         uscpi->remaining_length = message_size - uscpi->response_length;
 405
 406         return transferred - USBTMC_BULK_HEADER_SIZE;
 407 }
 408
 409 static int scpi_usbtmc_bulkin_continue(struct scpi_usbtmc_libusb *uscpi,
 410                                        void *data, int size)
 411 {
 412         struct sr_usb_dev_inst *usb = uscpi->usb;
 413         int ret, transferred;
 414
 415         ret = libusb_bulk_transfer(usb->devhdl, uscpi->bulk_in_ep, data, size,
 416                                    &transferred, TRANSFER_TIMEOUT);
 417         if (ret) {
 418                 sr_err("USBTMC bulk in transfer error: %d", ret);
 419                 return SR_ERR;
 420         }
 421
 422         uscpi->response_length = MIN(transferred, uscpi->remaining_length);
 423         uscpi->response_bytes_read = 0;
 424         uscpi->remaining_length -= uscpi->response_length;
 425
 426         return transferred;
 427 }
 428
 429 static int scpi_usbtmc_libusb_send(void *priv, const char *command)
 430 {
 431         struct scpi_usbtmc_libusb *uscpi = priv;
 432
 433         if (scpi_usbtmc_bulkout(uscpi, DEV_DEP_MSG_OUT,
 434                                 command, strlen(command), EOM) <= 0)
 435                 return SR_ERR;
 436
 437         sr_spew("Successfully sent SCPI command: '%s'.", command);
 438
 439         return SR_OK;
 440 }
 441
 442 static int scpi_usbtmc_libusb_read_begin(void *priv)
 443 {
 444         struct scpi_usbtmc_libusb *uscpi = priv;
 445
 446         uscpi->remaining_length = 0;
 447
 448         if (scpi_usbtmc_bulkout(uscpi, REQUEST_DEV_DEP_MSG_IN,
 449             NULL, INT32_MAX, 0) < 0)
 450                 return SR_ERR;
 451         if (scpi_usbtmc_bulkin_start(uscpi, DEV_DEP_MSG_IN,
 452                                      uscpi->buffer, sizeof(uscpi->buffer),
 453                                      &uscpi->bulkin_attributes) < 0)
 454                 return SR_ERR;
 455
 456         return SR_OK;
 457 }
 458
 459 static int scpi_usbtmc_libusb_read_data(void *priv, char *buf, int maxlen)
 460 {
 461         struct scpi_usbtmc_libusb *uscpi = priv;
 462         int read_length;
 463
 464         if (uscpi->response_bytes_read >= uscpi->response_length) {
 465                 if (uscpi->remaining_length > 0) {
 466                         if (scpi_usbtmc_bulkin_continue(uscpi, uscpi->buffer,
 467                                                         sizeof(uscpi->buffer)) <= 0)
 468                                 return SR_ERR;
 469                 } else {
 470                         if (uscpi->bulkin_attributes & EOM)
 471                                 return SR_ERR;
 472                         if (scpi_usbtmc_libusb_read_begin(uscpi) < 0)
 473                                 return SR_ERR;
 474                 }
 475         }
 476
 477         read_length = MIN(uscpi->response_length - uscpi->response_bytes_read, maxlen);
 478
 479         memcpy(buf, uscpi->buffer + uscpi->response_bytes_read, read_length);
 480
 481         uscpi->response_bytes_read += read_length;
 482
 483         return read_length;
 484 }
 485
 486 static int scpi_usbtmc_libusb_read_complete(void *priv)
 487 {
 488         struct scpi_usbtmc_libusb *uscpi = priv;
 489         return uscpi->response_bytes_read >= uscpi->response_length &&
 490                uscpi->remaining_length <= 0 &&
 491                uscpi->bulkin_attributes & EOM;
 492 }
 493
 494 static int scpi_usbtmc_libusb_close(void *priv)
 495 {
 496         struct scpi_usbtmc_libusb *uscpi = priv;
 497         struct sr_usb_dev_inst *usb = uscpi->usb;
 498
 499         if (!usb->devhdl)
 500                 return SR_ERR;
 501
 502         libusb_clear_halt(usb->devhdl, uscpi->bulk_in_ep);
 503         libusb_clear_halt(usb->devhdl, uscpi->bulk_out_ep);
 504         libusb_clear_halt(usb->devhdl, uscpi->interrupt_ep);
 505         libusb_release_interface(usb->devhdl, uscpi->interface);
 506         if (uscpi->detached_kernel_driver) {
 507                 libusb_attach_kernel_driver(usb->devhdl, uscpi->interface);
 508                 uscpi->detached_kernel_driver = 0;
 509         }
 510         libusb_close(usb->devhdl);
 511         usb->devhdl = NULL;
 512
 513         return SR_OK;
 514 }
 515
 516 static void scpi_usbtmc_libusb_free(void *priv)
 517 {
 518         struct scpi_usbtmc_libusb *uscpi = priv;
 519         sr_usb_dev_inst_free(uscpi->usb);
 520 }
 521
 522
 523 SR_PRIV const struct sr_scpi_dev_inst scpi_usbtmc_libusb_dev = {
 524         .name          = "USBTMC",
 525         .prefix        = "usbtmc",
 526         .priv_size     = sizeof(struct scpi_usbtmc_libusb),
 527         .scan          = scpi_usbtmc_libusb_scan,
 528         .dev_inst_new  = scpi_usbtmc_libusb_dev_inst_new,
 529         .open          = scpi_usbtmc_libusb_open,
 530         .source_add    = scpi_usbtmc_libusb_source_add,
 531         .source_remove = scpi_usbtmc_libusb_source_remove,
 532         .send          = scpi_usbtmc_libusb_send,
 533         .read_begin    = scpi_usbtmc_libusb_read_begin,
 534         .read_data     = scpi_usbtmc_libusb_read_data,
 535         .read_complete = scpi_usbtmc_libusb_read_complete,
 536         .close         = scpi_usbtmc_libusb_close,
 537         .free          = scpi_usbtmc_libusb_free,
 538 };