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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 = true; /* match if we don't enter the loop (no filter) */
  85                 for (int id = 0; vids[id] || pids[id]; id++) {
  86                         id_match = !vids[id] || dev_desc.idVendor == vids[id];
  87                         id_match &= !pids[id] || dev_desc.idProduct == pids[id];
  88
  89                         if (id_match)
  90                                 break;
  91                 }
  92
  93                 if (!id_match)
  94                         continue;
  95
  96                 /* Don't continue if we asked for a serial number and the device doesn't have one */
  97                 if (dev_desc.iSerialNumber == 0 && serial && serial[0])
  98                         continue;
  99
 100                 libusb_device_handle *dev_handle = NULL;
 101                 err = libusb_open(dev, &dev_handle);
 102                 if (err) {
 103                         /* It's to be expected that most USB devices can't be opened
 104                          * so only report an error if it was explicitly selected
 105                          */
 106                         if (vids[0] || pids[0]) {
 107                                 LOG_ERROR("could not open device 0x%04x:0x%04x: %s",
 108                                                 dev_desc.idVendor, dev_desc.idProduct, libusb_strerror(err));
 109                         } else {
 110                                 LOG_DEBUG("could not open device 0x%04x:0x%04x: %s",
 111                                                 dev_desc.idVendor, dev_desc.idProduct, libusb_strerror(err));
 112                         }
 113                         continue;
 114                 }
 115
 116                 /* Match serial number */
 117
 118                 bool serial_match = (serial == NULL);
 119                 char dev_serial[256] = {0};
 120                 if (dev_desc.iSerialNumber > 0) {
 121                         err = libusb_get_string_descriptor_ascii(
 122                                         dev_handle, dev_desc.iSerialNumber,
 123                                         (uint8_t *)dev_serial, sizeof(dev_serial));
 124
 125                         if (err < 0) {
 126                                 LOG_ERROR("could not read serial number for device 0x%04x:0x%04x: %s",
 127                                                 dev_desc.idVendor, dev_desc.idProduct, libusb_strerror(err));
 128                         } else if (serial && strncmp(dev_serial, serial, sizeof(dev_serial)) == 0) {
 129                                 serial_match = true;
 130                         }
 131                 }
 132
 133                 if (!serial_match) {
 134                         libusb_close(dev_handle);
 135                         continue;
 136                 }
 137
 138                 /* Find the CMSIS-DAP string in product string */
 139
 140                 bool cmsis_dap_found = false;
 141                 char product_string[256] = {0};
 142                 if (dev_desc.iProduct > 0) {
 143                         err = libusb_get_string_descriptor_ascii(
 144                                         dev_handle, dev_desc.iProduct,
 145                                         (uint8_t *)product_string, sizeof(product_string));
 146                         if (err < 0) {
 147                                 LOG_ERROR("could not read product string for device 0x%04x:0x%04x: %s",
 148                                                 dev_desc.idVendor, dev_desc.idProduct, libusb_strerror(err));
 149                         } else if (strstr(product_string, "CMSIS-DAP")) {
 150                                 LOG_DEBUG("CMSIS-DAP found in product string");
 151                                 cmsis_dap_found = true;
 152                         }
 153                 }
 154
 155                 /* Find the CMSIS-DAP interface */
 156
 157                 for (int config = 0; config < dev_desc.bNumConfigurations; config++) {
 158                         struct libusb_config_descriptor *config_desc;
 159                         err = libusb_get_config_descriptor(dev, config, &config_desc);
 160                         if (err) {
 161                                 LOG_ERROR("could not get configuration descriptor %d for device 0x%04x:0x%04x: %s",
 162                                                 config, dev_desc.idVendor, dev_desc.idProduct, libusb_strerror(err));
 163                                 continue;
 164                         }
 165
 166                         int config_num = config_desc->bConfigurationValue;
 167
 168                         for (int interface = 0; interface < config_desc->bNumInterfaces; interface++) {
 169                                 const struct libusb_interface_descriptor *intf_desc = &config_desc->interface[interface].altsetting[0];
 170                                 int interface_num = intf_desc->bInterfaceNumber;
 171
 172                                 /* Skip this interface if another one was requested explicitly */
 173                                 if (cmsis_dap_usb_interface != -1 && cmsis_dap_usb_interface != interface_num)
 174                                         continue;
 175
 176                                 /* CMSIS-DAP v2 spec says:
 177                                  *
 178                                  * CMSIS-DAP with default V2 configuration uses WinUSB and is therefore faster.
 179                                  * Optionally support for streaming SWO trace is provided via an additional USB endpoint.
 180                                  *
 181                                  * The WinUSB configuration requires custom class support with the interface setting
 182                                  *     Class Code: 0xFF (Vendor specific)
 183                                  *     Subclass: 0x00
 184                                  *     Protocol code: 0x00
 185                                  *
 186                                  * Depending on the configuration it uses the following USB endpoints which should be configured
 187                                  * in the interface descriptor in this order:
 188                                  *  - Endpoint 1: Bulk Out – used for commands received from host PC.
 189                                  *  - Endpoint 2: Bulk In – used for responses send to host PC.
 190                                  *  - Endpoint 3: Bulk In (optional) – used for streaming SWO trace (if enabled with SWO_STREAM).
 191                                  */
 192
 193                                 if (intf_desc->bNumEndpoints < 2)
 194                                         continue;
 195
 196                                 if ((intf_desc->endpoint[0].bmAttributes & 3) != LIBUSB_TRANSFER_TYPE_BULK ||
 197                                                 (intf_desc->endpoint[0].bEndpointAddress & 0x80) != LIBUSB_ENDPOINT_OUT)
 198                                         continue;
 199
 200                                 if ((intf_desc->endpoint[1].bmAttributes & 3) != LIBUSB_TRANSFER_TYPE_BULK ||
 201                                                 (intf_desc->endpoint[1].bEndpointAddress & 0x80) != LIBUSB_ENDPOINT_IN)
 202                                         continue;
 203
 204                                 /* Bypass the following checks if this interface was explicitly requested. */
 205                                 if (cmsis_dap_usb_interface == -1) {
 206                                         if (intf_desc->bInterfaceClass != LIBUSB_CLASS_VENDOR_SPEC ||
 207                                                         intf_desc->bInterfaceSubClass != 0 || intf_desc->bInterfaceProtocol != 0)
 208                                                 continue;
 209
 210                                         /* Search for "CMSIS-DAP" in the interface string */
 211                                         if (cmsis_dap_usb_interface != -1 && !cmsis_dap_found) {
 212                                                 if (intf_desc->iInterface == 0)
 213                                                         continue;
 214
 215                                                 char interface_str[256] = {0};
 216
 217                                                 err = libusb_get_string_descriptor_ascii(
 218                                                                 dev_handle, intf_desc->iInterface,
 219                                                                 (uint8_t *)interface_str, sizeof(interface_str));
 220                                                 if (err < 0) {
 221                                                         LOG_ERROR("could not read interface string for device 0x%04x:0x%04x: %s",
 222                                                                         dev_desc.idVendor, dev_desc.idProduct, libusb_strerror(err));
 223                                                         continue;
 224                                                 } else if (!strstr(interface_str, "CMSIS-DAP")) {
 225                                                         continue;
 226                                                 } else {
 227                                                         LOG_DEBUG("CMSIS-DAP found in interface string");
 228                                                 }
 229                                         }
 230                                 }
 231
 232                                 int packet_size = intf_desc->endpoint[0].wMaxPacketSize;
 233                                 int ep_out = intf_desc->endpoint[0].bEndpointAddress;
 234                                 int ep_in = intf_desc->endpoint[1].bEndpointAddress;
 235
 236                                 /* That's the one! */
 237                                 libusb_free_config_descriptor(config_desc);
 238                                 libusb_free_device_list(device_list, true);
 239
 240                                 LOG_INFO("Using CMSIS-DAPv2 interface with VID:PID=0x%04x:0x%04x, serial=%s",
 241                                                 dev_desc.idVendor, dev_desc.idProduct, dev_serial);
 242
 243                                 int current_config;
 244                                 err = libusb_get_configuration(dev_handle, &current_config);
 245                                 if (err) {
 246                                         LOG_ERROR("could not find current configuration: %s", libusb_strerror(err));
 247                                         libusb_close(dev_handle);
 248                                         libusb_exit(ctx);
 249                                         return ERROR_FAIL;
 250                                 }
 251
 252                                 if (config_num != current_config) {
 253                                         err = libusb_set_configuration(dev_handle, config_num);
 254                                         if (err) {
 255                                                 LOG_ERROR("could not set configuration: %s", libusb_strerror(err));
 256                                                 libusb_close(dev_handle);
 257                                                 libusb_exit(ctx);
 258                                                 return ERROR_FAIL;
 259                                         }
 260                                 }
 261
 262                                 err = libusb_claim_interface(dev_handle, interface_num);
 263                                 if (err)
 264                                         LOG_WARNING("could not claim interface: %s", libusb_strerror(err));
 265
 266                                 dap->bdata = malloc(sizeof(struct cmsis_dap_backend_data));
 267                                 if (dap->bdata == NULL) {
 268                                         LOG_ERROR("unable to allocate memory");
 269                                         libusb_release_interface(dev_handle, interface_num);
 270                                         libusb_close(dev_handle);
 271                                         libusb_exit(ctx);
 272                                         return ERROR_FAIL;
 273                                 }
 274
 275                                 dap->packet_size = packet_size + 1; /* "+ 1" for compatibility with the HID backend */
 276                                 dap->bdata->usb_ctx = ctx;
 277                                 dap->bdata->dev_handle = dev_handle;
 278                                 dap->bdata->ep_out = ep_out;
 279                                 dap->bdata->ep_in = ep_in;
 280                                 dap->bdata->interface = interface_num;
 281                                 return ERROR_OK;
 282                         }
 283
 284                         libusb_free_config_descriptor(config_desc);
 285                 }
 286
 287                 libusb_close(dev_handle);
 288         }
 289
 290         libusb_free_device_list(device_list, true);
 291
 292         libusb_exit(ctx);
 293         return ERROR_FAIL;
 294 }
 295
 296 static void cmsis_dap_usb_close(struct cmsis_dap *dap)
 297 {
 298         libusb_release_interface(dap->bdata->dev_handle, dap->bdata->interface);
 299         libusb_close(dap->bdata->dev_handle);
 300         libusb_exit(dap->bdata->usb_ctx);
 301         free(dap->bdata);
 302         dap->bdata = NULL;
 303 }
 304
 305 static int cmsis_dap_usb_read(struct cmsis_dap *dap, int timeout_ms)
 306 {
 307         int transferred = 0;
 308         int err;
 309
 310         err = libusb_bulk_transfer(dap->bdata->dev_handle, dap->bdata->ep_in,
 311                                                         dap->packet_buffer, dap->packet_size, &transferred, timeout_ms);
 312         if (err) {
 313                 if (err == LIBUSB_ERROR_TIMEOUT) {
 314                         return ERROR_TIMEOUT_REACHED;
 315                 } else {
 316                         LOG_ERROR("error reading data: %s", libusb_strerror(err));
 317                         return ERROR_FAIL;
 318                 }
 319         }
 320
 321         memset(&dap->packet_buffer[transferred], 0, dap->packet_size - transferred);
 322
 323         return transferred;
 324 }
 325
 326 static int cmsis_dap_usb_write(struct cmsis_dap *dap, int txlen, int timeout_ms)
 327 {
 328         int transferred = 0;
 329         int err;
 330
 331         /* skip the first byte that is only used by the HID backend */
 332         err = libusb_bulk_transfer(dap->bdata->dev_handle, dap->bdata->ep_out,
 333                                                         dap->packet_buffer + 1, txlen - 1, &transferred, timeout_ms);
 334         if (err) {
 335                 if (err == LIBUSB_ERROR_TIMEOUT) {
 336                         return ERROR_TIMEOUT_REACHED;
 337                 } else {
 338                         LOG_ERROR("error writing data: %s", libusb_strerror(err));
 339                         return ERROR_FAIL;
 340                 }
 341         }
 342
 343         return transferred;
 344 }
 345
 346 COMMAND_HANDLER(cmsis_dap_handle_usb_interface_command)
 347 {
 348         if (CMD_ARGC == 1)
 349                 cmsis_dap_usb_interface = strtoul(CMD_ARGV[0], NULL, 10);
 350         else
 351                 LOG_ERROR("expected exactly one argument to cmsis_dap_usb_interface <interface_number>");
 352
 353         return ERROR_OK;
 354 }
 355
 356 const struct command_registration cmsis_dap_usb_subcommand_handlers[] = {
 357         {
 358                 .name = "interface",
 359                 .handler = &cmsis_dap_handle_usb_interface_command,
 360                 .mode = COMMAND_CONFIG,
 361                 .help = "set the USB interface number to use (for USB bulk backend only)",
 362                 .usage = "<interface_number>",
 363         },
 364         COMMAND_REGISTRATION_DONE
 365 };
 366
 367 const struct cmsis_dap_backend cmsis_dap_usb_backend = {
 368         .name = "usb_bulk",
 369         .open = cmsis_dap_usb_open,
 370         .close = cmsis_dap_usb_close,
 371         .read = cmsis_dap_usb_read,
 372         .write = cmsis_dap_usb_write,
 373 };