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   1 /***************************************************************************
   2  *   Copyright (C) 2018 by Mickaël Thomas                                  *
   3  *   mickael9@gmail.com                                                    *
   4  *                                                                         *
   5  *   Copyright (C) 2016 by Maksym Hilliaka                                 *
   6  *   oter@frozen-team.com                                                  *
   7  *                                                                         *
   8  *   Copyright (C) 2016 by Phillip Pearson                                 *
   9  *   pp@myelin.co.nz                                                       *
  10  *                                                                         *
  11  *   Copyright (C) 2014 by Paul Fertser                                    *
  12  *   fercerpav@gmail.com                                                   *
  13  *                                                                         *
  14  *   Copyright (C) 2013 by mike brown                                      *
  15  *   mike@theshedworks.org.uk                                              *
  16  *                                                                         *
  17  *   Copyright (C) 2013 by Spencer Oliver                                  *
  18  *   spen@spen-soft.co.uk                                                  *
  19  *                                                                         *
  20  *   This program is free software; you can redistribute it and/or modify  *
  21  *   it under the terms of the GNU General Public License as published by  *
  22  *   the Free Software Foundation; either version 2 of the License, or     *
  23  *   (at your option) any later version.                                   *
  24  *                                                                         *
  25  *   This program is distributed in the hope that it will be useful,       *
  26  *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
  27  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
  28  *   GNU General Public License for more details.                          *
  29  *                                                                         *
  30  *   You should have received a copy of the GNU General Public License     *
  31  *   along with this program.  If not, see <http://www.gnu.org/licenses/>. *
  32  ***************************************************************************/
  33
  34 #ifdef HAVE_CONFIG_H
  35 #include "config.h"
  36 #endif
  37
  38 #include <libusb.h>
  39 #include <helper/log.h>
  40
  41 #include "cmsis_dap.h"
  42
  43 struct cmsis_dap_backend_data {
  44         libusb_context *usb_ctx;
  45         libusb_device_handle *dev_handle;
  46         unsigned int ep_out;
  47         unsigned int ep_in;
  48         int interface;
  49 };
  50
  51 static int cmsis_dap_usb_interface = -1;
  52
  53 static void cmsis_dap_usb_close(struct cmsis_dap *dap);
  54 static int cmsis_dap_usb_alloc(struct cmsis_dap *dap, unsigned int pkt_sz);
  55
  56 static int cmsis_dap_usb_open(struct cmsis_dap *dap, uint16_t vids[], uint16_t pids[], char *serial)
  57 {
  58         int err;
  59         libusb_context *ctx;
  60         libusb_device **device_list;
  61
  62         err = libusb_init(&ctx);
  63         if (err) {
  64                 LOG_ERROR("libusb initialization failed: %s", libusb_strerror(err));
  65                 return ERROR_FAIL;
  66         }
  67
  68         int num_devices = libusb_get_device_list(ctx, &device_list);
  69         if (num_devices < 0) {
  70                 LOG_ERROR("could not enumerate USB devices: %s", libusb_strerror(num_devices));
  71                 libusb_exit(ctx);
  72                 return ERROR_FAIL;
  73         }
  74
  75         for (int i = 0; i < num_devices; i++) {
  76                 libusb_device *dev = device_list[i];
  77                 struct libusb_device_descriptor dev_desc;
  78
  79                 err = libusb_get_device_descriptor(dev, &dev_desc);
  80                 if (err) {
  81                         LOG_ERROR("could not get device descriptor for device %d: %s", i, libusb_strerror(err));
  82                         continue;
  83                 }
  84
  85                 /* Match VID/PID */
  86
  87                 bool id_match = false;
  88                 bool id_filter = vids[0] || pids[0];
  89                 for (int id = 0; vids[id] || pids[id]; id++) {
  90                         id_match = !vids[id] || dev_desc.idVendor == vids[id];
  91                         id_match &= !pids[id] || dev_desc.idProduct == pids[id];
  92
  93                         if (id_match)
  94                                 break;
  95                 }
  96
  97                 if (id_filter && !id_match)
  98                         continue;
  99
 100                 /* Don't continue if we asked for a serial number and the device doesn't have one */
 101                 if (dev_desc.iSerialNumber == 0 && serial && serial[0])
 102                         continue;
 103
 104                 libusb_device_handle *dev_handle = NULL;
 105                 err = libusb_open(dev, &dev_handle);
 106                 if (err) {
 107                         /* It's to be expected that most USB devices can't be opened
 108                          * so only report an error if it was explicitly selected
 109                          */
 110                         if (id_filter) {
 111                                 LOG_ERROR("could not open device 0x%04x:0x%04x: %s",
 112                                                 dev_desc.idVendor, dev_desc.idProduct, libusb_strerror(err));
 113                         } else {
 114                                 LOG_DEBUG("could not open device 0x%04x:0x%04x: %s",
 115                                                 dev_desc.idVendor, dev_desc.idProduct, libusb_strerror(err));
 116                         }
 117                         continue;
 118                 }
 119
 120                 /* Match serial number */
 121
 122                 bool serial_match = false;
 123                 char dev_serial[256] = {0};
 124                 if (dev_desc.iSerialNumber > 0) {
 125                         err = libusb_get_string_descriptor_ascii(
 126                                         dev_handle, dev_desc.iSerialNumber,
 127                                         (uint8_t *)dev_serial, sizeof(dev_serial));
 128
 129                         if (err < 0) {
 130                                 const char *msg = "could not read serial number for device 0x%04x:0x%04x: %s";
 131                                 if (serial)
 132                                         LOG_WARNING(msg, dev_desc.idVendor, dev_desc.idProduct,
 133                                                                 libusb_strerror(err));
 134                                 else
 135                                         LOG_DEBUG(msg, dev_desc.idVendor, dev_desc.idProduct,
 136                                                                 libusb_strerror(err));
 137                         } else if (serial && strncmp(dev_serial, serial, sizeof(dev_serial)) == 0) {
 138                                 serial_match = true;
 139                         }
 140                 }
 141
 142                 if (serial && !serial_match) {
 143                         libusb_close(dev_handle);
 144                         continue;
 145                 }
 146
 147                 /* Find the CMSIS-DAP string in product string */
 148
 149                 bool cmsis_dap_in_product_str = false;
 150                 char product_string[256] = {0};
 151                 if (dev_desc.iProduct > 0) {
 152                         err = libusb_get_string_descriptor_ascii(
 153                                         dev_handle, dev_desc.iProduct,
 154                                         (uint8_t *)product_string, sizeof(product_string));
 155                         if (err < 0) {
 156                                 LOG_WARNING("could not read product string for device 0x%04x:0x%04x: %s",
 157                                                 dev_desc.idVendor, dev_desc.idProduct, libusb_strerror(err));
 158                         } else if (strstr(product_string, "CMSIS-DAP")) {
 159                                 LOG_DEBUG("found product string of 0x%04x:0x%04x '%s'",
 160                                                   dev_desc.idVendor, dev_desc.idProduct, product_string);
 161                                 cmsis_dap_in_product_str = true;
 162                         }
 163                 }
 164
 165                 bool device_identified_reliably = cmsis_dap_in_product_str
 166                                                                                         || serial_match || id_match;
 167
 168                 /* Find the CMSIS-DAP interface */
 169
 170                 for (int config = 0; config < dev_desc.bNumConfigurations; config++) {
 171                         struct libusb_config_descriptor *config_desc;
 172                         err = libusb_get_config_descriptor(dev, config, &config_desc);
 173                         if (err) {
 174                                 LOG_ERROR("could not get configuration descriptor %d for device 0x%04x:0x%04x: %s",
 175                                                 config, dev_desc.idVendor, dev_desc.idProduct, libusb_strerror(err));
 176                                 continue;
 177                         }
 178
 179                         LOG_DEBUG("enumerating interfaces of 0x%04x:0x%04x",
 180                                           dev_desc.idVendor, dev_desc.idProduct);
 181                         int config_num = config_desc->bConfigurationValue;
 182                         const struct libusb_interface_descriptor *intf_desc_candidate = NULL;
 183                         const struct libusb_interface_descriptor *intf_desc_found = NULL;
 184
 185                         for (int interface = 0; interface < config_desc->bNumInterfaces; interface++) {
 186                                 const struct libusb_interface_descriptor *intf_desc = &config_desc->interface[interface].altsetting[0];
 187                                 int interface_num = intf_desc->bInterfaceNumber;
 188
 189                                 /* Skip this interface if another one was requested explicitly */
 190                                 if (cmsis_dap_usb_interface != -1 && cmsis_dap_usb_interface != interface_num)
 191                                         continue;
 192
 193                                 /* CMSIS-DAP v2 spec says:
 194                                  *
 195                                  * CMSIS-DAP with default V2 configuration uses WinUSB and is therefore faster.
 196                                  * Optionally support for streaming SWO trace is provided via an additional USB endpoint.
 197                                  *
 198                                  * The WinUSB configuration requires custom class support with the interface setting
 199                                  *     Class Code: 0xFF (Vendor specific)
 200                                  *     Subclass: 0x00
 201                                  *     Protocol code: 0x00
 202                                  *
 203                                  * Depending on the configuration it uses the following USB endpoints which should be configured
 204                                  * in the interface descriptor in this order:
 205                                  *  - Endpoint 1: Bulk Out – used for commands received from host PC.
 206                                  *  - Endpoint 2: Bulk In – used for responses send to host PC.
 207                                  *  - Endpoint 3: Bulk In (optional) – used for streaming SWO trace (if enabled with SWO_STREAM).
 208                                  */
 209
 210                                 /* Search for "CMSIS-DAP" in the interface string */
 211                                 bool cmsis_dap_in_interface_str = false;
 212                                 if (intf_desc->iInterface != 0) {
 213
 214                                         char interface_str[256] = {0};
 215
 216                                         err = libusb_get_string_descriptor_ascii(
 217                                                         dev_handle, intf_desc->iInterface,
 218                                                         (uint8_t *)interface_str, sizeof(interface_str));
 219                                         if (err < 0) {
 220                                                 LOG_DEBUG("could not read interface string %d for device 0x%04x:0x%04x: %s",
 221                                                                   intf_desc->iInterface,
 222                                                                   dev_desc.idVendor, dev_desc.idProduct,
 223                                                                   libusb_strerror(err));
 224                                         } else if (strstr(interface_str, "CMSIS-DAP")) {
 225                                                 cmsis_dap_in_interface_str = true;
 226                                                 LOG_DEBUG("found interface %d string '%s'",
 227                                                                   interface_num, interface_str);
 228                                         }
 229                                 }
 230
 231                                 /* Bypass the following check if this interface was explicitly requested. */
 232                                 if (cmsis_dap_usb_interface == -1) {
 233                                         if (!cmsis_dap_in_product_str && !cmsis_dap_in_interface_str)
 234                                                 continue;
 235                                 }
 236
 237                                 /* check endpoints */
 238                                 if (intf_desc->bNumEndpoints < 2) {
 239                                         LOG_DEBUG("skipping interface %d, has only %d endpoints",
 240                                                           interface_num, intf_desc->bNumEndpoints);
 241                                         continue;
 242                                 }
 243
 244                                 if ((intf_desc->endpoint[0].bmAttributes & 3) != LIBUSB_TRANSFER_TYPE_BULK ||
 245                                                 (intf_desc->endpoint[0].bEndpointAddress & 0x80) != LIBUSB_ENDPOINT_OUT) {
 246                                         LOG_DEBUG("skipping interface %d, endpoint[0] is not bulk out",
 247                                                           interface_num);
 248                                         continue;
 249                                 }
 250
 251                                 if ((intf_desc->endpoint[1].bmAttributes & 3) != LIBUSB_TRANSFER_TYPE_BULK ||
 252                                                 (intf_desc->endpoint[1].bEndpointAddress & 0x80) != LIBUSB_ENDPOINT_IN) {
 253                                         LOG_DEBUG("skipping interface %d, endpoint[1] is not bulk in",
 254                                                           interface_num);
 255                                         continue;
 256                                 }
 257
 258                                 /* We can rely on the interface is really CMSIS-DAP if
 259                                  * - we've seen CMSIS-DAP in the interface string
 260                                  * - config asked explicitly for an interface number
 261                                  * - the device has only one interface
 262                                  * The later two cases should be honored only if we know
 263                                  * we are on the rigt device */
 264                                 bool intf_identified_reliably = cmsis_dap_in_interface_str
 265                                                         || (device_identified_reliably &&
 266                                                                         (cmsis_dap_usb_interface != -1
 267                                                                          || config_desc->bNumInterfaces == 1));
 268
 269                                 if (intf_desc->bInterfaceClass != LIBUSB_CLASS_VENDOR_SPEC ||
 270                                                 intf_desc->bInterfaceSubClass != 0 || intf_desc->bInterfaceProtocol != 0) {
 271                                         /* If the interface is reliably identified
 272                                          * then we need not insist on setting USB class, subclass and protocol
 273                                          * exactly as the specification requires.
 274                                          * At least KitProg3 uses class 0 contrary to the specification */
 275                                         if (intf_identified_reliably) {
 276                                                 LOG_WARNING("Using CMSIS-DAPv2 interface %d with wrong class %" PRId8
 277                                                                   " subclass %" PRId8 " or protocol %" PRId8,
 278                                                                   interface_num,
 279                                                                   intf_desc->bInterfaceClass,
 280                                                                   intf_desc->bInterfaceSubClass,
 281                                                                   intf_desc->bInterfaceProtocol);
 282                                         } else {
 283                                                 LOG_DEBUG("skipping interface %d, class %" PRId8
 284                                                                   " subclass %" PRId8 " protocol %" PRId8,
 285                                                                   interface_num,
 286                                                                   intf_desc->bInterfaceClass,
 287                                                                   intf_desc->bInterfaceSubClass,
 288                                                                   intf_desc->bInterfaceProtocol);
 289                                                 continue;
 290
 291                                         }
 292                                 }
 293
 294                                 if (intf_identified_reliably) {
 295                                         /* That's the one! */
 296                                         intf_desc_found = intf_desc;
 297                                         break;
 298                                 }
 299
 300                                 if (!intf_desc_candidate && device_identified_reliably) {
 301                                         /* This interface looks suitable for CMSIS-DAP. Store the pointer to it
 302                                          * and keep searching for another one with CMSIS-DAP in interface string */
 303                                         intf_desc_candidate = intf_desc;
 304                                 }
 305                         }
 306
 307                         if (!intf_desc_found) {
 308                                 /* We were not able to identify reliably which interface is CMSIS-DAP.
 309                                  * Let's use the first suitable if we found one */
 310                                 intf_desc_found = intf_desc_candidate;
 311                         }
 312
 313                         if (!intf_desc_found) {
 314                                 libusb_free_config_descriptor(config_desc);
 315                                 continue;
 316                         }
 317
 318                         /* We've chosen an interface, connect to it */
 319                         int interface_num = intf_desc_found->bInterfaceNumber;
 320                         int packet_size = intf_desc_found->endpoint[0].wMaxPacketSize;
 321                         int ep_out = intf_desc_found->endpoint[0].bEndpointAddress;
 322                         int ep_in = intf_desc_found->endpoint[1].bEndpointAddress;
 323
 324                         libusb_free_config_descriptor(config_desc);
 325                         libusb_free_device_list(device_list, true);
 326
 327                         LOG_INFO("Using CMSIS-DAPv2 interface with VID:PID=0x%04x:0x%04x, serial=%s",
 328                                         dev_desc.idVendor, dev_desc.idProduct, dev_serial);
 329
 330                         int current_config;
 331                         err = libusb_get_configuration(dev_handle, &current_config);
 332                         if (err) {
 333                                 LOG_ERROR("could not find current configuration: %s", libusb_strerror(err));
 334                                 libusb_close(dev_handle);
 335                                 libusb_exit(ctx);
 336                                 return ERROR_FAIL;
 337                         }
 338
 339                         if (config_num != current_config) {
 340                                 err = libusb_set_configuration(dev_handle, config_num);
 341                                 if (err) {
 342                                         LOG_ERROR("could not set configuration: %s", libusb_strerror(err));
 343                                         libusb_close(dev_handle);
 344                                         libusb_exit(ctx);
 345                                         return ERROR_FAIL;
 346                                 }
 347                         }
 348
 349                         err = libusb_claim_interface(dev_handle, interface_num);
 350                         if (err)
 351                                 LOG_WARNING("could not claim interface: %s", libusb_strerror(err));
 352
 353                         dap->bdata = malloc(sizeof(struct cmsis_dap_backend_data));
 354                         if (dap->bdata == NULL) {
 355                                 LOG_ERROR("unable to allocate memory");
 356                                 libusb_release_interface(dev_handle, interface_num);
 357                                 libusb_close(dev_handle);
 358                                 libusb_exit(ctx);
 359                                 return ERROR_FAIL;
 360                         }
 361
 362                         dap->packet_size = packet_size;
 363                         dap->packet_buffer_size = packet_size + REPORT_ID_SIZE;
 364                         dap->bdata->usb_ctx = ctx;
 365                         dap->bdata->dev_handle = dev_handle;
 366                         dap->bdata->ep_out = ep_out;
 367                         dap->bdata->ep_in = ep_in;
 368                         dap->bdata->interface = interface_num;
 369
 370                         dap->packet_buffer = malloc(dap->packet_buffer_size);
 371                         if (dap->packet_buffer == NULL) {
 372                                 LOG_ERROR("unable to allocate memory");
 373                                 cmsis_dap_usb_close(dap);
 374                                 return ERROR_FAIL;
 375                         }
 376
 377                         return ERROR_OK;
 378                 }
 379
 380                 libusb_close(dev_handle);
 381         }
 382
 383         libusb_free_device_list(device_list, true);
 384
 385         libusb_exit(ctx);
 386         return ERROR_FAIL;
 387 }
 388
 389 static void cmsis_dap_usb_close(struct cmsis_dap *dap)
 390 {
 391         libusb_release_interface(dap->bdata->dev_handle, dap->bdata->interface);
 392         libusb_close(dap->bdata->dev_handle);
 393         libusb_exit(dap->bdata->usb_ctx);
 394         free(dap->bdata);
 395         dap->bdata = NULL;
 396         free(dap->packet_buffer);
 397         dap->packet_buffer = NULL;
 398 }
 399
 400 static int cmsis_dap_usb_read(struct cmsis_dap *dap, int timeout_ms)
 401 {
 402         int transferred = 0;
 403         int err;
 404
 405         err = libusb_bulk_transfer(dap->bdata->dev_handle, dap->bdata->ep_in,
 406                                                         dap->packet_buffer, dap->packet_size, &transferred, timeout_ms);
 407         if (err) {
 408                 if (err == LIBUSB_ERROR_TIMEOUT) {
 409                         return ERROR_TIMEOUT_REACHED;
 410                 } else {
 411                         LOG_ERROR("error reading data: %s", libusb_strerror(err));
 412                         return ERROR_FAIL;
 413                 }
 414         }
 415
 416         memset(&dap->packet_buffer[transferred], 0, dap->packet_buffer_size - transferred);
 417
 418         return transferred;
 419 }
 420
 421 static int cmsis_dap_usb_write(struct cmsis_dap *dap, int txlen, int timeout_ms)
 422 {
 423         int transferred = 0;
 424         int err;
 425
 426         /* skip the first byte that is only used by the HID backend */
 427         err = libusb_bulk_transfer(dap->bdata->dev_handle, dap->bdata->ep_out,
 428                                                         dap->packet_buffer + REPORT_ID_SIZE, txlen - REPORT_ID_SIZE, &transferred, timeout_ms);
 429         if (err) {
 430                 if (err == LIBUSB_ERROR_TIMEOUT) {
 431                         return ERROR_TIMEOUT_REACHED;
 432                 } else {
 433                         LOG_ERROR("error writing data: %s", libusb_strerror(err));
 434                         return ERROR_FAIL;
 435                 }
 436         }
 437
 438         return transferred;
 439 }
 440
 441 static int cmsis_dap_usb_alloc(struct cmsis_dap *dap, unsigned int pkt_sz)
 442 {
 443         unsigned int packet_buffer_size = pkt_sz + REPORT_ID_SIZE;
 444         uint8_t *buf = malloc(packet_buffer_size);
 445         if (buf == NULL) {
 446                 LOG_ERROR("unable to allocate CMSIS-DAP packet buffer");
 447                 return ERROR_FAIL;
 448         }
 449
 450         dap->packet_buffer = buf;
 451         dap->packet_size = pkt_sz;
 452         dap->packet_buffer_size = packet_buffer_size;
 453
 454         return ERROR_OK;
 455 }
 456
 457 COMMAND_HANDLER(cmsis_dap_handle_usb_interface_command)
 458 {
 459         if (CMD_ARGC == 1)
 460                 cmsis_dap_usb_interface = strtoul(CMD_ARGV[0], NULL, 10);
 461         else
 462                 LOG_ERROR("expected exactly one argument to cmsis_dap_usb_interface <interface_number>");
 463
 464         return ERROR_OK;
 465 }
 466
 467 const struct command_registration cmsis_dap_usb_subcommand_handlers[] = {
 468         {
 469                 .name = "interface",
 470                 .handler = &cmsis_dap_handle_usb_interface_command,
 471                 .mode = COMMAND_CONFIG,
 472                 .help = "set the USB interface number to use (for USB bulk backend only)",
 473                 .usage = "<interface_number>",
 474         },
 475         COMMAND_REGISTRATION_DONE
 476 };
 477
 478 const struct cmsis_dap_backend cmsis_dap_usb_backend = {
 479         .name = "usb_bulk",
 480         .open = cmsis_dap_usb_open,
 481         .close = cmsis_dap_usb_close,
 482         .read = cmsis_dap_usb_read,
 483         .write = cmsis_dap_usb_write,
 484         .packet_buffer_alloc = cmsis_dap_usb_alloc,
 485 };