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