libjaylink/discovery_usb.c

   1 /*
   2  * This file is part of the libjaylink project.
   3  *
   4  * Copyright (C) 2014-2016 Marc Schink <jaylink-dev@marcschink.de>
   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 2 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 <stdlib.h>
  21 #include <stdint.h>
  22 #include <stdbool.h>
  23 #include <string.h>
  24 #include <sys/types.h>
  25
  26 #include "libjaylink.h"
  27 #include "libjaylink-internal.h"
  28
  29 /*
  30  * libusb.h includes windows.h and therefore must be included after anything
  31  * that includes winsock2.h.
  32  */
  33 #include <libusb.h>
  34
  35 /**
  36  * @file
  37  *
  38  * Device discovery (USB).
  39  */
  40
  41 /** @cond PRIVATE */
  42 /** USB Vendor ID (VID) of SEGGER products. */
  43 #define USB_VENDOR_ID                   0x1366
  44
  45 /* USB Product IDs (PID) and their corresponding USB addresses. */
  46 static const uint16_t pids[][2] = {
  47         {0x0101, 0},
  48         {0x0102, 1},
  49         {0x0103, 2},
  50         {0x0104, 3},
  51         {0x0105, 0},
  52         {0x0107, 0},
  53         {0x0108, 0},
  54         {0x1010, 0},
  55         {0x1011, 0},
  56         {0x1012, 0},
  57         {0x1013, 0},
  58         {0x1014, 0},
  59         {0x1015, 0},
  60         {0x1016, 0},
  61         {0x1017, 0},
  62         {0x1018, 0}
  63 };
  64
  65 /** Maximum length of the USB string descriptor for the serial number. */
  66 #define USB_SERIAL_NUMBER_LENGTH        12
  67
  68 /**
  69  * Maximum number of digits in a serial number
  70  *
  71  * The serial number of a device consists of at most 9 digits but user defined
  72  * serial numbers are allowed with up to 10 digits.
  73  */
  74 #define MAX_SERIAL_NUMBER_DIGITS        10
  75 /** @endcond */
  76
  77 static bool parse_serial_number(const char *str, uint32_t *serial_number)
  78 {
  79         size_t length;
  80
  81         length = strlen(str);
  82
  83         /*
  84          * Skip the first digits which are not part of a valid serial number.
  85          * This is necessary because some devices erroneously use random digits
  86          * instead of zeros for padding.
  87          */
  88         if (length > MAX_SERIAL_NUMBER_DIGITS)
  89                 str = str + (length - MAX_SERIAL_NUMBER_DIGITS);
  90
  91         if (jaylink_parse_serial_number(str, serial_number) != JAYLINK_OK)
  92                 return false;
  93
  94         return true;
  95 }
  96
  97 static bool compare_devices(const void *a, const void *b)
  98 {
  99         const struct jaylink_device *dev;
 100         const struct libusb_device *usb_dev;
 101
 102         dev = a;
 103         usb_dev = b;
 104
 105         if (dev->iface != JAYLINK_HIF_USB)
 106                 return false;
 107
 108         if (dev->usb_dev == usb_dev)
 109                 return true;
 110
 111         return false;
 112 }
 113
 114 static struct jaylink_device *find_device(const struct jaylink_context *ctx,
 115                 const struct libusb_device *usb_dev)
 116 {
 117         struct list *item;
 118
 119         item = list_find_custom(ctx->devs, &compare_devices, usb_dev);
 120
 121         if (item)
 122                 return item->data;
 123
 124         return NULL;
 125 }
 126
 127 static struct jaylink_device *probe_device(struct jaylink_context *ctx,
 128                 struct libusb_device *usb_dev)
 129 {
 130         int ret;
 131         struct libusb_device_descriptor desc;
 132         struct libusb_device_handle *usb_devh;
 133         struct jaylink_device *dev;
 134         char buf[USB_SERIAL_NUMBER_LENGTH + 1];
 135         uint8_t usb_address;
 136         uint32_t serial_number;
 137         bool valid_serial_number;
 138         bool found_device;
 139         size_t i;
 140
 141         ret = libusb_get_device_descriptor(usb_dev, &desc);
 142
 143         if (ret != LIBUSB_SUCCESS) {
 144                 log_warn(ctx, "Failed to get device descriptor: %s.",
 145                         libusb_error_name(ret));
 146                 return NULL;
 147         }
 148
 149         if (desc.idVendor != USB_VENDOR_ID)
 150                 return NULL;
 151
 152         found_device = false;
 153
 154         for (i = 0; i < sizeof(pids) / sizeof(pids[0]); i++) {
 155                 if (pids[i][0] == desc.idProduct) {
 156                         found_device = true;
 157                         usb_address = pids[i][1];
 158                         break;
 159                 }
 160         }
 161
 162         if (!found_device)
 163                 return NULL;
 164
 165         log_dbg(ctx, "Found device (VID:PID = %04x:%04x, bus:address = "
 166                 "%03u:%03u).", desc.idVendor, desc.idProduct,
 167                 libusb_get_bus_number(usb_dev),
 168                 libusb_get_device_address(usb_dev));
 169
 170         /*
 171          * Search for an already allocated device instance for this device and
 172          * if found return a reference to it.
 173          */
 174         dev = find_device(ctx, usb_dev);
 175
 176         if (dev) {
 177                 log_dbg(ctx, "Device: USB address = %u.", dev->usb_address);
 178
 179                 if (dev->valid_serial_number)
 180                         log_dbg(ctx, "Device: Serial number = %u.",
 181                                 dev->serial_number);
 182                 else
 183                         log_dbg(ctx, "Device: Serial number = N/A.");
 184
 185                 log_dbg(ctx, "Using existing device instance.");
 186                 return jaylink_ref_device(dev);
 187         }
 188
 189         /* Open the device to be able to retrieve its serial number. */
 190         ret = libusb_open(usb_dev, &usb_devh);
 191
 192         if (ret != LIBUSB_SUCCESS) {
 193                 log_warn(ctx, "Failed to open device: %s.",
 194                         libusb_error_name(ret));
 195                 return NULL;
 196         }
 197
 198         serial_number = 0;
 199         valid_serial_number = true;
 200
 201         ret = libusb_get_string_descriptor_ascii(usb_devh, desc.iSerialNumber,
 202                 (unsigned char *)buf, USB_SERIAL_NUMBER_LENGTH + 1);
 203
 204         libusb_close(usb_devh);
 205
 206         if (ret < 0) {
 207                 log_warn(ctx, "Failed to retrieve serial number: %s.",
 208                         libusb_error_name(ret));
 209                 valid_serial_number = false;
 210         }
 211
 212         if (valid_serial_number) {
 213                 if (!parse_serial_number(buf, &serial_number)) {
 214                         log_warn(ctx, "Failed to parse serial number.");
 215                         return NULL;
 216                 }
 217         }
 218
 219         log_dbg(ctx, "Device: USB address = %u.", usb_address);
 220
 221         if (valid_serial_number)
 222                 log_dbg(ctx, "Device: Serial number = %u.", serial_number);
 223         else
 224                 log_dbg(ctx, "Device: Serial number = N/A.");
 225
 226         log_dbg(ctx, "Allocating new device instance.");
 227
 228         dev = device_allocate(ctx);
 229
 230         if (!dev) {
 231                 log_warn(ctx, "Device instance malloc failed.");
 232                 return NULL;
 233         }
 234
 235         dev->iface = JAYLINK_HIF_USB;
 236         dev->usb_dev = libusb_ref_device(usb_dev);
 237         dev->usb_address = usb_address;
 238         dev->serial_number = serial_number;
 239         dev->valid_serial_number = valid_serial_number;
 240
 241         return dev;
 242 }
 243
 244 JAYLINK_PRIV int discovery_usb_scan(struct jaylink_context *ctx)
 245 {
 246         ssize_t ret;
 247         struct libusb_device **devs;
 248         struct jaylink_device *dev;
 249         size_t num;
 250         size_t i;
 251
 252         ret = libusb_get_device_list(ctx->usb_ctx, &devs);
 253
 254         if (ret == LIBUSB_ERROR_IO) {
 255                 log_err(ctx, "Failed to retrieve device list: input/output "
 256                         "error.");
 257                 return JAYLINK_ERR_IO;
 258         } else if (ret < 0) {
 259                 log_err(ctx, "Failed to retrieve device list: %s.",
 260                         libusb_error_name(ret));
 261                 return JAYLINK_ERR;
 262         }
 263
 264         num = 0;
 265
 266         for (i = 0; devs[i]; i++) {
 267                 dev = probe_device(ctx, devs[i]);
 268
 269                 if (!dev)
 270                         continue;
 271
 272                 ctx->discovered_devs = list_prepend(ctx->discovered_devs, dev);
 273                 num++;
 274         }
 275
 276         libusb_free_device_list(devs, true);
 277         log_dbg(ctx, "Found %zu USB device(s).", num);
 278
 279         return JAYLINK_OK;
 280 }