drivers/net/usb/kalmia.c

   1 /*
   2  * USB network interface driver for Samsung Kalmia based LTE USB modem like the
   3  * Samsung GT-B3730 and GT-B3710.
   4  *
   5  * Copyright (C) 2011 Marius Bjoernstad Kotsbak <marius@kotsbak.com>
   6  *
   7  * Sponsored by Quicklink Video Distribution Services Ltd.
   8  *
   9  * Based on the cdc_eem module.
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License as published by
  13  * the Free Software Foundation; either version 2 of the License, or
  14  * (at your option) any later version.
  15  */
  16
  17 #include <linux/module.h>
  18 #include <linux/init.h>
  19 #include <linux/netdevice.h>
  20 #include <linux/etherdevice.h>
  21 #include <linux/ctype.h>
  22 #include <linux/ethtool.h>
  23 #include <linux/workqueue.h>
  24 #include <linux/mii.h>
  25 #include <linux/usb.h>
  26 #include <linux/crc32.h>
  27 #include <linux/usb/cdc.h>
  28 #include <linux/usb/usbnet.h>
  29 #include <linux/gfp.h>
  30
  31 /*
  32  * The Samsung Kalmia based LTE USB modems have a CDC ACM port for modem control
  33  * handled by the "option" module and an ethernet data port handled by this
  34  * module.
  35  *
  36  * The stick must first be switched into modem mode by usb_modeswitch
  37  * or similar tool. Then the modem gets sent two initialization packets by
  38  * this module, which gives the MAC address of the device. User space can then
  39  * connect the modem using AT commands through the ACM port and then use
  40  * DHCP on the network interface exposed by this module. Network packets are
  41  * sent to and from the modem in a proprietary format discovered after watching
  42  * the behavior of the windows driver for the modem.
  43  *
  44  * More information about the use of the modem is available in usb_modeswitch
  45  * forum and the project page:
  46  *
  47  * http://www.draisberghof.de/usb_modeswitch/bb/viewtopic.php?t=465
  48  * https://github.com/mkotsbak/Samsung-GT-B3730-linux-driver
  49  */
  50
  51 /* #define      DEBUG */
  52 /* #define      VERBOSE */
  53
  54 #define KALMIA_HEADER_LENGTH 6
  55 #define KALMIA_ALIGN_SIZE 4
  56 #define KALMIA_USB_TIMEOUT 10000
  57
  58 /*-------------------------------------------------------------------------*/
  59
  60 static int
  61 kalmia_send_init_packet(struct usbnet *dev, u8 *init_msg, u8 init_msg_len,
  62         u8 *buffer, u8 expected_len)
  63 {
  64         int act_len;
  65         int status;
  66
  67         netdev_dbg(dev->net, "Sending init packet");
  68
  69         status = usb_bulk_msg(dev->udev, usb_sndbulkpipe(dev->udev, 0x02),
  70                 init_msg, init_msg_len, &act_len, KALMIA_USB_TIMEOUT);
  71         if (status != 0) {
  72                 netdev_err(dev->net,
  73                         "Error sending init packet. Status %i, length %i\n",
  74                         status, act_len);
  75                 return status;
  76         }
  77         else if (act_len != init_msg_len) {
  78                 netdev_err(dev->net,
  79                         "Did not send all of init packet. Bytes sent: %i",
  80                         act_len);
  81         }
  82         else {
  83                 netdev_dbg(dev->net, "Successfully sent init packet.");
  84         }
  85
  86         status = usb_bulk_msg(dev->udev, usb_rcvbulkpipe(dev->udev, 0x81),
  87                 buffer, expected_len, &act_len, KALMIA_USB_TIMEOUT);
  88
  89         if (status != 0)
  90                 netdev_err(dev->net,
  91                         "Error receiving init result. Status %i, length %i\n",
  92                         status, act_len);
  93         else if (act_len != expected_len)
  94                 netdev_err(dev->net, "Unexpected init result length: %i\n",
  95                         act_len);
  96
  97         return status;
  98 }
  99
 100 static int
 101 kalmia_init_and_get_ethernet_addr(struct usbnet *dev, u8 *ethernet_addr)
 102 {
 103         char init_msg_1[] =
 104                 { 0x57, 0x50, 0x04, 0x00, 0x00, 0x00, 0x00, 0x20, 0x00, 0x00,
 105                 0x00, 0x00 };
 106         char init_msg_2[] =
 107                 { 0x57, 0x50, 0x04, 0x00, 0x00, 0x00, 0x00, 0x02, 0x00, 0xf4,
 108                 0x00, 0x00 };
 109         char receive_buf[28];
 110         int status;
 111
 112         status = kalmia_send_init_packet(dev, init_msg_1, sizeof(init_msg_1)
 113                 / sizeof(init_msg_1[0]), receive_buf, 24);
 114         if (status != 0)
 115                 return status;
 116
 117         status = kalmia_send_init_packet(dev, init_msg_2, sizeof(init_msg_2)
 118                 / sizeof(init_msg_2[0]), receive_buf, 28);
 119         if (status != 0)
 120                 return status;
 121
 122         memcpy(ethernet_addr, receive_buf + 10, ETH_ALEN);
 123
 124         return status;
 125 }
 126
 127 static int
 128 kalmia_bind(struct usbnet *dev, struct usb_interface *intf)
 129 {
 130         u8 status;
 131         u8 ethernet_addr[ETH_ALEN];
 132
 133         /* Don't bind to AT command interface */
 134         if (intf->cur_altsetting->desc.bInterfaceClass != USB_CLASS_VENDOR_SPEC)
 135                 return -EINVAL;
 136
 137         dev->in = usb_rcvbulkpipe(dev->udev, 0x81 & USB_ENDPOINT_NUMBER_MASK);
 138         dev->out = usb_sndbulkpipe(dev->udev, 0x02 & USB_ENDPOINT_NUMBER_MASK);
 139         dev->status = NULL;
 140
 141         dev->net->hard_header_len += KALMIA_HEADER_LENGTH;
 142         dev->hard_mtu = 1400;
 143         dev->rx_urb_size = dev->hard_mtu * 10; // Found as optimal after testing
 144
 145         status = kalmia_init_and_get_ethernet_addr(dev, ethernet_addr);
 146
 147         if (status < 0) {
 148                 usb_set_intfdata(intf, NULL);
 149                 usb_driver_release_interface(driver_of(intf), intf);
 150                 return status;
 151         }
 152
 153         memcpy(dev->net->dev_addr, ethernet_addr, ETH_ALEN);
 154         memcpy(dev->net->perm_addr, ethernet_addr, ETH_ALEN);
 155
 156         return status;
 157 }
 158
 159 static struct sk_buff *
 160 kalmia_tx_fixup(struct usbnet *dev, struct sk_buff *skb, gfp_t flags)
 161 {
 162         struct sk_buff *skb2 = NULL;
 163         u16 content_len;
 164         unsigned char *header_start;
 165         unsigned char ether_type_1, ether_type_2;
 166         u8 remainder, padlen = 0;
 167
 168         if (!skb_cloned(skb)) {
 169                 int headroom = skb_headroom(skb);
 170                 int tailroom = skb_tailroom(skb);
 171
 172                 if ((tailroom >= KALMIA_ALIGN_SIZE) && (headroom
 173                         >= KALMIA_HEADER_LENGTH))
 174                         goto done;
 175
 176                 if ((headroom + tailroom) > (KALMIA_HEADER_LENGTH
 177                         + KALMIA_ALIGN_SIZE)) {
 178                         skb->data = memmove(skb->head + KALMIA_HEADER_LENGTH,
 179                                 skb->data, skb->len);
 180                         skb_set_tail_pointer(skb, skb->len);
 181                         goto done;
 182                 }
 183         }
 184
 185         skb2 = skb_copy_expand(skb, KALMIA_HEADER_LENGTH,
 186                 KALMIA_ALIGN_SIZE, flags);
 187         if (!skb2)
 188                 return NULL;
 189
 190         dev_kfree_skb_any(skb);
 191         skb = skb2;
 192
 193         done: header_start = skb_push(skb, KALMIA_HEADER_LENGTH);
 194         ether_type_1 = header_start[KALMIA_HEADER_LENGTH + 12];
 195         ether_type_2 = header_start[KALMIA_HEADER_LENGTH + 13];
 196
 197         netdev_dbg(dev->net, "Sending etherType: %02x%02x", ether_type_1,
 198                 ether_type_2);
 199
 200         /* According to empiric data for data packages */
 201         header_start[0] = 0x57;
 202         header_start[1] = 0x44;
 203         content_len = skb->len - KALMIA_HEADER_LENGTH;
 204         header_start[2] = (content_len & 0xff); /* low byte */
 205         header_start[3] = (content_len >> 8); /* high byte */
 206
 207         header_start[4] = ether_type_1;
 208         header_start[5] = ether_type_2;
 209
 210         /* Align to 4 bytes by padding with zeros */
 211         remainder = skb->len % KALMIA_ALIGN_SIZE;
 212         if (remainder > 0) {
 213                 padlen = KALMIA_ALIGN_SIZE - remainder;
 214                 memset(skb_put(skb, padlen), 0, padlen);
 215         }
 216
 217         netdev_dbg(
 218                 dev->net,
 219                 "Sending package with length %i and padding %i. Header: %02x:%02x:%02x:%02x:%02x:%02x.",
 220                 content_len, padlen, header_start[0], header_start[1],
 221                 header_start[2], header_start[3], header_start[4],
 222                 header_start[5]);
 223
 224         return skb;
 225 }
 226
 227 static int
 228 kalmia_rx_fixup(struct usbnet *dev, struct sk_buff *skb)
 229 {
 230         /*
 231          * Our task here is to strip off framing, leaving skb with one
 232          * data frame for the usbnet framework code to process.
 233          */
 234         const u8 HEADER_END_OF_USB_PACKET[] =
 235                 { 0x57, 0x5a, 0x00, 0x00, 0x08, 0x00 };
 236         const u8 EXPECTED_UNKNOWN_HEADER_1[] =
 237                 { 0x57, 0x43, 0x1e, 0x00, 0x15, 0x02 };
 238         const u8 EXPECTED_UNKNOWN_HEADER_2[] =
 239                 { 0x57, 0x50, 0x0e, 0x00, 0x00, 0x00 };
 240         u8 i = 0;
 241
 242         /* incomplete header? */
 243         if (skb->len < KALMIA_HEADER_LENGTH)
 244                 return 0;
 245
 246         do {
 247                 struct sk_buff *skb2 = NULL;
 248                 u8 *header_start;
 249                 u16 usb_packet_length, ether_packet_length;
 250                 int is_last;
 251
 252                 header_start = skb->data;
 253
 254                 if (unlikely(header_start[0] != 0x57 || header_start[1] != 0x44)) {
 255                         if (!memcmp(header_start, EXPECTED_UNKNOWN_HEADER_1,
 256                                 sizeof(EXPECTED_UNKNOWN_HEADER_1)) || !memcmp(
 257                                 header_start, EXPECTED_UNKNOWN_HEADER_2,
 258                                 sizeof(EXPECTED_UNKNOWN_HEADER_2))) {
 259                                 netdev_dbg(
 260                                         dev->net,
 261                                         "Received expected unknown frame header: %02x:%02x:%02x:%02x:%02x:%02x. Package length: %i\n",
 262                                         header_start[0], header_start[1],
 263                                         header_start[2], header_start[3],
 264                                         header_start[4], header_start[5],
 265                                         skb->len - KALMIA_HEADER_LENGTH);
 266                         }
 267                         else {
 268                                 netdev_err(
 269                                         dev->net,
 270                                         "Received unknown frame header: %02x:%02x:%02x:%02x:%02x:%02x. Package length: %i\n",
 271                                         header_start[0], header_start[1],
 272                                         header_start[2], header_start[3],
 273                                         header_start[4], header_start[5],
 274                                         skb->len - KALMIA_HEADER_LENGTH);
 275                                 return 0;
 276                         }
 277                 }
 278                 else
 279                         netdev_dbg(
 280                                 dev->net,
 281                                 "Received header: %02x:%02x:%02x:%02x:%02x:%02x. Package length: %i\n",
 282                                 header_start[0], header_start[1], header_start[2],
 283                                 header_start[3], header_start[4], header_start[5],
 284                                 skb->len - KALMIA_HEADER_LENGTH);
 285
 286                 /* subtract start header and end header */
 287                 usb_packet_length = skb->len - (2 * KALMIA_HEADER_LENGTH);
 288                 ether_packet_length = header_start[2] + (header_start[3] << 8);
 289                 skb_pull(skb, KALMIA_HEADER_LENGTH);
 290
 291                 /* Some small packets misses end marker */
 292                 if (usb_packet_length < ether_packet_length) {
 293                         ether_packet_length = usb_packet_length
 294                                 + KALMIA_HEADER_LENGTH;
 295                         is_last = true;
 296                 }
 297                 else {
 298                         netdev_dbg(dev->net, "Correct package length #%i", i
 299                                 + 1);
 300
 301                         is_last = (memcmp(skb->data + ether_packet_length,
 302                                 HEADER_END_OF_USB_PACKET,
 303                                 sizeof(HEADER_END_OF_USB_PACKET)) == 0);
 304                         if (!is_last) {
 305                                 header_start = skb->data + ether_packet_length;
 306                                 netdev_dbg(
 307                                         dev->net,
 308                                         "End header: %02x:%02x:%02x:%02x:%02x:%02x. Package length: %i\n",
 309                                         header_start[0], header_start[1],
 310                                         header_start[2], header_start[3],
 311                                         header_start[4], header_start[5],
 312                                         skb->len - KALMIA_HEADER_LENGTH);
 313                         }
 314                 }
 315
 316                 if (is_last) {
 317                         skb2 = skb;
 318                 }
 319                 else {
 320                         skb2 = skb_clone(skb, GFP_ATOMIC);
 321                         if (unlikely(!skb2))
 322                                 return 0;
 323                 }
 324
 325                 skb_trim(skb2, ether_packet_length);
 326
 327                 if (is_last) {
 328                         return 1;
 329                 }
 330                 else {
 331                         usbnet_skb_return(dev, skb2);
 332                         skb_pull(skb, ether_packet_length);
 333                 }
 334
 335                 i++;
 336         }
 337         while (skb->len);
 338
 339         return 1;
 340 }
 341
 342 static const struct driver_info kalmia_info = {
 343         .description = "Samsung Kalmia LTE USB dongle",
 344         .flags = FLAG_WWAN,
 345         .bind = kalmia_bind,
 346         .rx_fixup = kalmia_rx_fixup,
 347         .tx_fixup = kalmia_tx_fixup
 348 };
 349
 350 /*-------------------------------------------------------------------------*/
 351
 352 static const struct usb_device_id products[] = {
 353         /* The unswitched USB ID, to get the module auto loaded: */
 354         { USB_DEVICE(0x04e8, 0x689a) },
 355         /* The stick swithed into modem (by e.g. usb_modeswitch): */
 356         { USB_DEVICE(0x04e8, 0x6889),
 357                 .driver_info = (unsigned long) &kalmia_info, },
 358         { /* EMPTY == end of list */} };
 359 MODULE_DEVICE_TABLE( usb, products);
 360
 361 static struct usb_driver kalmia_driver = {
 362         .name = "kalmia",
 363         .id_table = products,
 364         .probe = usbnet_probe,
 365         .disconnect = usbnet_disconnect,
 366         .suspend = usbnet_suspend,
 367         .resume = usbnet_resume
 368 };
 369
 370 static int __init kalmia_init(void)
 371 {
 372         return usb_register(&kalmia_driver);
 373 }
 374 module_init( kalmia_init);
 375
 376 static void __exit kalmia_exit(void)
 377 {
 378         usb_deregister(&kalmia_driver);
 379 }
 380 module_exit( kalmia_exit);
 381
 382 MODULE_AUTHOR("Marius Bjoernstad Kotsbak <marius@kotsbak.com>");
 383 MODULE_DESCRIPTION("Samsung Kalmia USB network driver");
 384 MODULE_LICENSE("GPL");