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/netdevice.h>
  19 #include <linux/etherdevice.h>
  20 #include <linux/ctype.h>
  21 #include <linux/ethtool.h>
  22 #include <linux/workqueue.h>
  23 #include <linux/mii.h>
  24 #include <linux/usb.h>
  25 #include <linux/crc32.h>
  26 #include <linux/usb/cdc.h>
  27 #include <linux/usb/usbnet.h>
  28 #include <linux/gfp.h>
  29
  30 /*
  31  * The Samsung Kalmia based LTE USB modems have a CDC ACM port for modem control
  32  * handled by the "option" module and an ethernet data port handled by this
  33  * module.
  34  *
  35  * The stick must first be switched into modem mode by usb_modeswitch
  36  * or similar tool. Then the modem gets sent two initialization packets by
  37  * this module, which gives the MAC address of the device. User space can then
  38  * connect the modem using AT commands through the ACM port and then use
  39  * DHCP on the network interface exposed by this module. Network packets are
  40  * sent to and from the modem in a proprietary format discovered after watching
  41  * the behavior of the windows driver for the modem.
  42  *
  43  * More information about the use of the modem is available in usb_modeswitch
  44  * forum and the project page:
  45  *
  46  * http://www.draisberghof.de/usb_modeswitch/bb/viewtopic.php?t=465
  47  * https://github.com/mkotsbak/Samsung-GT-B3730-linux-driver
  48  */
  49
  50 /* #define      DEBUG */
  51 /* #define      VERBOSE */
  52
  53 #define KALMIA_HEADER_LENGTH 6
  54 #define KALMIA_ALIGN_SIZE 4
  55 #define KALMIA_USB_TIMEOUT 10000
  56
  57 /*-------------------------------------------------------------------------*/
  58
  59 static int
  60 kalmia_send_init_packet(struct usbnet *dev, u8 *init_msg, u8 init_msg_len,
  61         u8 *buffer, u8 expected_len)
  62 {
  63         int act_len;
  64         int status;
  65
  66         netdev_dbg(dev->net, "Sending init packet");
  67
  68         status = usb_bulk_msg(dev->udev, usb_sndbulkpipe(dev->udev, 0x02),
  69                 init_msg, init_msg_len, &act_len, KALMIA_USB_TIMEOUT);
  70         if (status != 0) {
  71                 netdev_err(dev->net,
  72                         "Error sending init packet. Status %i, length %i\n",
  73                         status, act_len);
  74                 return status;
  75         }
  76         else if (act_len != init_msg_len) {
  77                 netdev_err(dev->net,
  78                         "Did not send all of init packet. Bytes sent: %i",
  79                         act_len);
  80         }
  81         else {
  82                 netdev_dbg(dev->net, "Successfully sent init packet.");
  83         }
  84
  85         status = usb_bulk_msg(dev->udev, usb_rcvbulkpipe(dev->udev, 0x81),
  86                 buffer, expected_len, &act_len, KALMIA_USB_TIMEOUT);
  87
  88         if (status != 0)
  89                 netdev_err(dev->net,
  90                         "Error receiving init result. Status %i, length %i\n",
  91                         status, act_len);
  92         else if (act_len != expected_len)
  93                 netdev_err(dev->net, "Unexpected init result length: %i\n",
  94                         act_len);
  95
  96         return status;
  97 }
  98
  99 static int
 100 kalmia_init_and_get_ethernet_addr(struct usbnet *dev, u8 *ethernet_addr)
 101 {
 102         static const char init_msg_1[] =
 103                 { 0x57, 0x50, 0x04, 0x00, 0x00, 0x00, 0x00, 0x20, 0x00, 0x00,
 104                 0x00, 0x00 };
 105         static const char init_msg_2[] =
 106                 { 0x57, 0x50, 0x04, 0x00, 0x00, 0x00, 0x00, 0x02, 0x00, 0xf4,
 107                 0x00, 0x00 };
 108         static const int buflen = 28;
 109         char *usb_buf;
 110         int status;
 111
 112         usb_buf = kmalloc(buflen, GFP_DMA | GFP_KERNEL);
 113         if (!usb_buf)
 114                 return -ENOMEM;
 115
 116         memcpy(usb_buf, init_msg_1, 12);
 117         status = kalmia_send_init_packet(dev, usb_buf, ARRAY_SIZE(init_msg_1),
 118                                          usb_buf, 24);
 119         if (status != 0)
 120                 return status;
 121
 122         memcpy(usb_buf, init_msg_2, 12);
 123         status = kalmia_send_init_packet(dev, usb_buf, ARRAY_SIZE(init_msg_2),
 124                                          usb_buf, 28);
 125         if (status != 0)
 126                 return status;
 127
 128         memcpy(ethernet_addr, usb_buf + 10, ETH_ALEN);
 129
 130         kfree(usb_buf);
 131         return status;
 132 }
 133
 134 static int
 135 kalmia_bind(struct usbnet *dev, struct usb_interface *intf)
 136 {
 137         int status;
 138         u8 ethernet_addr[ETH_ALEN];
 139
 140         /* Don't bind to AT command interface */
 141         if (intf->cur_altsetting->desc.bInterfaceClass != USB_CLASS_VENDOR_SPEC)
 142                 return -EINVAL;
 143
 144         dev->in = usb_rcvbulkpipe(dev->udev, 0x81 & USB_ENDPOINT_NUMBER_MASK);
 145         dev->out = usb_sndbulkpipe(dev->udev, 0x02 & USB_ENDPOINT_NUMBER_MASK);
 146         dev->status = NULL;
 147
 148         dev->net->hard_header_len += KALMIA_HEADER_LENGTH;
 149         dev->hard_mtu = 1400;
 150         dev->rx_urb_size = dev->hard_mtu * 10; // Found as optimal after testing
 151
 152         status = kalmia_init_and_get_ethernet_addr(dev, ethernet_addr);
 153         if (status)
 154                 return status;
 155
 156         memcpy(dev->net->dev_addr, ethernet_addr, ETH_ALEN);
 157
 158         return status;
 159 }
 160
 161 static struct sk_buff *
 162 kalmia_tx_fixup(struct usbnet *dev, struct sk_buff *skb, gfp_t flags)
 163 {
 164         struct sk_buff *skb2 = NULL;
 165         u16 content_len;
 166         unsigned char *header_start;
 167         unsigned char ether_type_1, ether_type_2;
 168         u8 remainder, padlen = 0;
 169
 170         if (!skb_cloned(skb)) {
 171                 int headroom = skb_headroom(skb);
 172                 int tailroom = skb_tailroom(skb);
 173
 174                 if ((tailroom >= KALMIA_ALIGN_SIZE) && (headroom
 175                         >= KALMIA_HEADER_LENGTH))
 176                         goto done;
 177
 178                 if ((headroom + tailroom) > (KALMIA_HEADER_LENGTH
 179                         + KALMIA_ALIGN_SIZE)) {
 180                         skb->data = memmove(skb->head + KALMIA_HEADER_LENGTH,
 181                                 skb->data, skb->len);
 182                         skb_set_tail_pointer(skb, skb->len);
 183                         goto done;
 184                 }
 185         }
 186
 187         skb2 = skb_copy_expand(skb, KALMIA_HEADER_LENGTH,
 188                 KALMIA_ALIGN_SIZE, flags);
 189         if (!skb2)
 190                 return NULL;
 191
 192         dev_kfree_skb_any(skb);
 193         skb = skb2;
 194
 195 done:
 196         header_start = skb_push(skb, KALMIA_HEADER_LENGTH);
 197         ether_type_1 = header_start[KALMIA_HEADER_LENGTH + 12];
 198         ether_type_2 = header_start[KALMIA_HEADER_LENGTH + 13];
 199
 200         netdev_dbg(dev->net, "Sending etherType: %02x%02x", ether_type_1,
 201                 ether_type_2);
 202
 203         /* According to empiric data for data packages */
 204         header_start[0] = 0x57;
 205         header_start[1] = 0x44;
 206         content_len = skb->len - KALMIA_HEADER_LENGTH;
 207
 208         put_unaligned_le16(content_len, &header_start[2]);
 209         header_start[4] = ether_type_1;
 210         header_start[5] = ether_type_2;
 211
 212         /* Align to 4 bytes by padding with zeros */
 213         remainder = skb->len % KALMIA_ALIGN_SIZE;
 214         if (remainder > 0) {
 215                 padlen = KALMIA_ALIGN_SIZE - remainder;
 216                 skb_put_zero(skb, padlen);
 217         }
 218
 219         netdev_dbg(dev->net,
 220                 "Sending package with length %i and padding %i. Header: %6phC.",
 221                 content_len, padlen, header_start);
 222
 223         return skb;
 224 }
 225
 226 static int
 227 kalmia_rx_fixup(struct usbnet *dev, struct sk_buff *skb)
 228 {
 229         /*
 230          * Our task here is to strip off framing, leaving skb with one
 231          * data frame for the usbnet framework code to process.
 232          */
 233         static const u8 HEADER_END_OF_USB_PACKET[] =
 234                 { 0x57, 0x5a, 0x00, 0x00, 0x08, 0x00 };
 235         static const u8 EXPECTED_UNKNOWN_HEADER_1[] =
 236                 { 0x57, 0x43, 0x1e, 0x00, 0x15, 0x02 };
 237         static const u8 EXPECTED_UNKNOWN_HEADER_2[] =
 238                 { 0x57, 0x50, 0x0e, 0x00, 0x00, 0x00 };
 239         int i = 0;
 240
 241         /* incomplete header? */
 242         if (skb->len < KALMIA_HEADER_LENGTH)
 243                 return 0;
 244
 245         do {
 246                 struct sk_buff *skb2 = NULL;
 247                 u8 *header_start;
 248                 u16 usb_packet_length, ether_packet_length;
 249                 int is_last;
 250
 251                 header_start = skb->data;
 252
 253                 if (unlikely(header_start[0] != 0x57 || header_start[1] != 0x44)) {
 254                         if (!memcmp(header_start, EXPECTED_UNKNOWN_HEADER_1,
 255                                 sizeof(EXPECTED_UNKNOWN_HEADER_1)) || !memcmp(
 256                                 header_start, EXPECTED_UNKNOWN_HEADER_2,
 257                                 sizeof(EXPECTED_UNKNOWN_HEADER_2))) {
 258                                 netdev_dbg(dev->net,
 259                                         "Received expected unknown frame header: %6phC. Package length: %i\n",
 260                                         header_start,
 261                                         skb->len - KALMIA_HEADER_LENGTH);
 262                         }
 263                         else {
 264                                 netdev_err(dev->net,
 265                                         "Received unknown frame header: %6phC. Package length: %i\n",
 266                                         header_start,
 267                                         skb->len - KALMIA_HEADER_LENGTH);
 268                                 return 0;
 269                         }
 270                 }
 271                 else
 272                         netdev_dbg(dev->net,
 273                                 "Received header: %6phC. Package length: %i\n",
 274                                 header_start, skb->len - KALMIA_HEADER_LENGTH);
 275
 276                 /* subtract start header and end header */
 277                 usb_packet_length = skb->len - (2 * KALMIA_HEADER_LENGTH);
 278                 ether_packet_length = get_unaligned_le16(&header_start[2]);
 279                 skb_pull(skb, KALMIA_HEADER_LENGTH);
 280
 281                 /* Some small packets misses end marker */
 282                 if (usb_packet_length < ether_packet_length) {
 283                         ether_packet_length = usb_packet_length
 284                                 + KALMIA_HEADER_LENGTH;
 285                         is_last = true;
 286                 }
 287                 else {
 288                         netdev_dbg(dev->net, "Correct package length #%i", i
 289                                 + 1);
 290
 291                         is_last = (memcmp(skb->data + ether_packet_length,
 292                                 HEADER_END_OF_USB_PACKET,
 293                                 sizeof(HEADER_END_OF_USB_PACKET)) == 0);
 294                         if (!is_last) {
 295                                 header_start = skb->data + ether_packet_length;
 296                                 netdev_dbg(dev->net,
 297                                         "End header: %6phC. Package length: %i\n",
 298                                         header_start,
 299                                         skb->len - KALMIA_HEADER_LENGTH);
 300                         }
 301                 }
 302
 303                 if (is_last) {
 304                         skb2 = skb;
 305                 }
 306                 else {
 307                         skb2 = skb_clone(skb, GFP_ATOMIC);
 308                         if (unlikely(!skb2))
 309                                 return 0;
 310                 }
 311
 312                 skb_trim(skb2, ether_packet_length);
 313
 314                 if (is_last) {
 315                         return 1;
 316                 }
 317                 else {
 318                         usbnet_skb_return(dev, skb2);
 319                         skb_pull(skb, ether_packet_length);
 320                 }
 321
 322                 i++;
 323         }
 324         while (skb->len);
 325
 326         return 1;
 327 }
 328
 329 static const struct driver_info kalmia_info = {
 330         .description = "Samsung Kalmia LTE USB dongle",
 331         .flags = FLAG_WWAN,
 332         .bind = kalmia_bind,
 333         .rx_fixup = kalmia_rx_fixup,
 334         .tx_fixup = kalmia_tx_fixup
 335 };
 336
 337 /*-------------------------------------------------------------------------*/
 338
 339 static const struct usb_device_id products[] = {
 340         /* The unswitched USB ID, to get the module auto loaded: */
 341         { USB_DEVICE(0x04e8, 0x689a) },
 342         /* The stick switched into modem (by e.g. usb_modeswitch): */
 343         { USB_DEVICE(0x04e8, 0x6889),
 344                 .driver_info = (unsigned long) &kalmia_info, },
 345         { /* EMPTY == end of list */} };
 346 MODULE_DEVICE_TABLE( usb, products);
 347
 348 static struct usb_driver kalmia_driver = {
 349         .name = "kalmia",
 350         .id_table = products,
 351         .probe = usbnet_probe,
 352         .disconnect = usbnet_disconnect,
 353         .suspend = usbnet_suspend,
 354         .resume = usbnet_resume,
 355         .disable_hub_initiated_lpm = 1,
 356 };
 357
 358 module_usb_driver(kalmia_driver);
 359
 360 MODULE_AUTHOR("Marius Bjoernstad Kotsbak <marius@kotsbak.com>");
 361 MODULE_DESCRIPTION("Samsung Kalmia USB network driver");
 362 MODULE_LICENSE("GPL");