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         {0x1020, 0}
  64 };
  65
  66 /** Maximum length of the USB string descriptor for the serial number. */
  67 #define USB_SERIAL_NUMBER_LENGTH        12
  68
  69 /**
  70  * Maximum number of digits in a serial number
  71  *
  72  * The serial number of a device consists of at most 9 digits but user defined
  73  * serial numbers are allowed with up to 10 digits.
  74  */
  75 #define MAX_SERIAL_NUMBER_DIGITS        10
  76 /** @endcond */
  77
  78 static bool parse_serial_number(const char *str, uint32_t *serial_number)
  79 {
  80         size_t length;
  81
  82         length = strlen(str);
  83
  84         /*
  85          * Skip the first digits which are not part of a valid serial number.
  86          * This is necessary because some devices erroneously use random digits
  87          * instead of zeros for padding.
  88          */
  89         if (length > MAX_SERIAL_NUMBER_DIGITS)
  90                 str = str + (length - MAX_SERIAL_NUMBER_DIGITS);
  91
  92         if (jaylink_parse_serial_number(str, serial_number) != JAYLINK_OK)
  93                 return false;
  94
  95         return true;
  96 }
  97
  98 static bool compare_devices(const void *a, const void *b)
  99 {
 100         const struct jaylink_device *dev;
 101         const struct libusb_device *usb_dev;
 102
 103         dev = a;
 104         usb_dev = b;
 105
 106         if (dev->iface != JAYLINK_HIF_USB)
 107                 return false;
 108
 109         if (dev->usb_dev == usb_dev)
 110                 return true;
 111
 112         return false;
 113 }
 114
 115 static struct jaylink_device *find_device(const struct jaylink_context *ctx,
 116                 const struct libusb_device *usb_dev)
 117 {
 118         struct list *item;
 119
 120         item = list_find_custom(ctx->devs, &compare_devices, usb_dev);
 121
 122         if (item)
 123                 return item->data;
 124
 125         return NULL;
 126 }
 127
 128 static struct jaylink_device *probe_device(struct jaylink_context *ctx,
 129                 struct libusb_device *usb_dev)
 130 {
 131         int ret;
 132         struct libusb_device_descriptor desc;
 133         struct libusb_device_handle *usb_devh;
 134         struct jaylink_device *dev;
 135         char buf[USB_SERIAL_NUMBER_LENGTH + 1];
 136         uint8_t usb_address;
 137         uint32_t serial_number;
 138         bool valid_serial_number;
 139         bool found_device;
 140         size_t i;
 141
 142         ret = libusb_get_device_descriptor(usb_dev, &desc);
 143
 144         if (ret != LIBUSB_SUCCESS) {
 145                 log_warn(ctx, "Failed to get device descriptor: %s.",
 146                         libusb_error_name(ret));
 147                 return NULL;
 148         }
 149
 150         if (desc.idVendor != USB_VENDOR_ID)
 151                 return NULL;
 152
 153         found_device = false;
 154
 155         for (i = 0; i < sizeof(pids) / sizeof(pids[0]); i++) {
 156                 if (pids[i][0] == desc.idProduct) {
 157                         found_device = true;
 158                         usb_address = pids[i][1];
 159                         break;
 160                 }
 161         }
 162
 163         if (!found_device)
 164                 return NULL;
 165
 166         log_dbg(ctx, "Found device (VID:PID = %04x:%04x, bus:address = "
 167                 "%03u:%03u).", desc.idVendor, desc.idProduct,
 168                 libusb_get_bus_number(usb_dev),
 169                 libusb_get_device_address(usb_dev));
 170
 171         /*
 172          * Search for an already allocated device instance for this device and
 173          * if found return a reference to it.
 174          */
 175         dev = find_device(ctx, usb_dev);
 176
 177         if (dev) {
 178                 log_dbg(ctx, "Device: USB address = %u.", dev->usb_address);
 179
 180                 if (dev->valid_serial_number)
 181                         log_dbg(ctx, "Device: Serial number = %u.",
 182                                 dev->serial_number);
 183                 else
 184                         log_dbg(ctx, "Device: Serial number = N/A.");
 185
 186                 log_dbg(ctx, "Using existing device instance.");
 187                 return jaylink_ref_device(dev);
 188         }
 189
 190         /* Open the device to be able to retrieve its serial number. */
 191         ret = libusb_open(usb_dev, &usb_devh);
 192
 193         if (ret != LIBUSB_SUCCESS) {
 194                 log_warn(ctx, "Failed to open device: %s.",
 195                         libusb_error_name(ret));
 196                 return NULL;
 197         }
 198
 199         serial_number = 0;
 200         valid_serial_number = true;
 201
 202         ret = libusb_get_string_descriptor_ascii(usb_devh, desc.iSerialNumber,
 203                 (unsigned char *)buf, USB_SERIAL_NUMBER_LENGTH + 1);
 204
 205         libusb_close(usb_devh);
 206
 207         if (ret < 0) {
 208                 log_warn(ctx, "Failed to retrieve serial number: %s.",
 209                         libusb_error_name(ret));
 210                 valid_serial_number = false;
 211         }
 212
 213         if (valid_serial_number) {
 214                 if (!parse_serial_number(buf, &serial_number)) {
 215                         log_warn(ctx, "Failed to parse serial number.");
 216                         return NULL;
 217                 }
 218         }
 219
 220         log_dbg(ctx, "Device: USB address = %u.", usb_address);
 221
 222         if (valid_serial_number)
 223                 log_dbg(ctx, "Device: Serial number = %u.", serial_number);
 224         else
 225                 log_dbg(ctx, "Device: Serial number = N/A.");
 226
 227         log_dbg(ctx, "Allocating new device instance.");
 228
 229         dev = device_allocate(ctx);
 230
 231         if (!dev) {
 232                 log_warn(ctx, "Device instance malloc failed.");
 233                 return NULL;
 234         }
 235
 236         dev->iface = JAYLINK_HIF_USB;
 237         dev->usb_dev = libusb_ref_device(usb_dev);
 238         dev->usb_address = usb_address;
 239         dev->serial_number = serial_number;
 240         dev->valid_serial_number = valid_serial_number;
 241
 242         return dev;
 243 }
 244
 245 JAYLINK_PRIV int discovery_usb_scan(struct jaylink_context *ctx)
 246 {
 247         ssize_t ret;
 248         struct libusb_device **devs;
 249         struct jaylink_device *dev;
 250         size_t num;
 251         size_t i;
 252
 253         ret = libusb_get_device_list(ctx->usb_ctx, &devs);
 254
 255         if (ret == LIBUSB_ERROR_IO) {
 256                 log_err(ctx, "Failed to retrieve device list: input/output "
 257                         "error.");
 258                 return JAYLINK_ERR_IO;
 259         } else if (ret < 0) {
 260                 log_err(ctx, "Failed to retrieve device list: %s.",
 261                         libusb_error_name(ret));
 262                 return JAYLINK_ERR;
 263         }
 264
 265         num = 0;
 266
 267         for (i = 0; devs[i]; i++) {
 268                 dev = probe_device(ctx, devs[i]);
 269
 270                 if (!dev)
 271                         continue;
 272
 273                 ctx->discovered_devs = list_prepend(ctx->discovered_devs, dev);
 274                 num++;
 275         }
 276
 277         libusb_free_device_list(devs, true);
 278         log_dbg(ctx, "Found %zu USB device(s).", num);
 279
 280         return JAYLINK_OK;
 281 }