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, sizeof(init_msg_1)
 118                 / sizeof(init_msg_1[0]), 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, sizeof(init_msg_2)
 124                 / sizeof(init_msg_2[0]), 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
 154         if (status) {
 155                 usb_set_intfdata(intf, NULL);
 156                 usb_driver_release_interface(driver_of(intf), intf);
 157                 return status;
 158         }
 159
 160         memcpy(dev->net->dev_addr, ethernet_addr, ETH_ALEN);
 161
 162         return status;
 163 }
 164
 165 static struct sk_buff *
 166 kalmia_tx_fixup(struct usbnet *dev, struct sk_buff *skb, gfp_t flags)
 167 {
 168         struct sk_buff *skb2 = NULL;
 169         u16 content_len;
 170         unsigned char *header_start;
 171         unsigned char ether_type_1, ether_type_2;
 172         u8 remainder, padlen = 0;
 173
 174         if (!skb_cloned(skb)) {
 175                 int headroom = skb_headroom(skb);
 176                 int tailroom = skb_tailroom(skb);
 177
 178                 if ((tailroom >= KALMIA_ALIGN_SIZE) && (headroom
 179                         >= KALMIA_HEADER_LENGTH))
 180                         goto done;
 181
 182                 if ((headroom + tailroom) > (KALMIA_HEADER_LENGTH
 183                         + KALMIA_ALIGN_SIZE)) {
 184                         skb->data = memmove(skb->head + KALMIA_HEADER_LENGTH,
 185                                 skb->data, skb->len);
 186                         skb_set_tail_pointer(skb, skb->len);
 187                         goto done;
 188                 }
 189         }
 190
 191         skb2 = skb_copy_expand(skb, KALMIA_HEADER_LENGTH,
 192                 KALMIA_ALIGN_SIZE, flags);
 193         if (!skb2)
 194                 return NULL;
 195
 196         dev_kfree_skb_any(skb);
 197         skb = skb2;
 198
 199 done:
 200         header_start = skb_push(skb, KALMIA_HEADER_LENGTH);
 201         ether_type_1 = header_start[KALMIA_HEADER_LENGTH + 12];
 202         ether_type_2 = header_start[KALMIA_HEADER_LENGTH + 13];
 203
 204         netdev_dbg(dev->net, "Sending etherType: %02x%02x", ether_type_1,
 205                 ether_type_2);
 206
 207         /* According to empiric data for data packages */
 208         header_start[0] = 0x57;
 209         header_start[1] = 0x44;
 210         content_len = skb->len - KALMIA_HEADER_LENGTH;
 211
 212         put_unaligned_le16(content_len, &header_start[2]);
 213         header_start[4] = ether_type_1;
 214         header_start[5] = ether_type_2;
 215
 216         /* Align to 4 bytes by padding with zeros */
 217         remainder = skb->len % KALMIA_ALIGN_SIZE;
 218         if (remainder > 0) {
 219                 padlen = KALMIA_ALIGN_SIZE - remainder;
 220                 skb_put_zero(skb, padlen);
 221         }
 222
 223         netdev_dbg(dev->net,
 224                 "Sending package with length %i and padding %i. Header: %6phC.",
 225                 content_len, padlen, header_start);
 226
 227         return skb;
 228 }
 229
 230 static int
 231 kalmia_rx_fixup(struct usbnet *dev, struct sk_buff *skb)
 232 {
 233         /*
 234          * Our task here is to strip off framing, leaving skb with one
 235          * data frame for the usbnet framework code to process.
 236          */
 237         static const u8 HEADER_END_OF_USB_PACKET[] =
 238                 { 0x57, 0x5a, 0x00, 0x00, 0x08, 0x00 };
 239         static const u8 EXPECTED_UNKNOWN_HEADER_1[] =
 240                 { 0x57, 0x43, 0x1e, 0x00, 0x15, 0x02 };
 241         static const u8 EXPECTED_UNKNOWN_HEADER_2[] =
 242                 { 0x57, 0x50, 0x0e, 0x00, 0x00, 0x00 };
 243         int i = 0;
 244
 245         /* incomplete header? */
 246         if (skb->len < KALMIA_HEADER_LENGTH)
 247                 return 0;
 248
 249         do {
 250                 struct sk_buff *skb2 = NULL;
 251                 u8 *header_start;
 252                 u16 usb_packet_length, ether_packet_length;
 253                 int is_last;
 254
 255                 header_start = skb->data;
 256
 257                 if (unlikely(header_start[0] != 0x57 || header_start[1] != 0x44)) {
 258                         if (!memcmp(header_start, EXPECTED_UNKNOWN_HEADER_1,
 259                                 sizeof(EXPECTED_UNKNOWN_HEADER_1)) || !memcmp(
 260                                 header_start, EXPECTED_UNKNOWN_HEADER_2,
 261                                 sizeof(EXPECTED_UNKNOWN_HEADER_2))) {
 262                                 netdev_dbg(dev->net,
 263                                         "Received expected unknown frame header: %6phC. Package length: %i\n",
 264                                         header_start,
 265                                         skb->len - KALMIA_HEADER_LENGTH);
 266                         }
 267                         else {
 268                                 netdev_err(dev->net,
 269                                         "Received unknown frame header: %6phC. Package length: %i\n",
 270                                         header_start,
 271                                         skb->len - KALMIA_HEADER_LENGTH);
 272                                 return 0;
 273                         }
 274                 }
 275                 else
 276                         netdev_dbg(dev->net,
 277                                 "Received header: %6phC. Package length: %i\n",
 278                                 header_start, skb->len - KALMIA_HEADER_LENGTH);
 279
 280                 /* subtract start header and end header */
 281                 usb_packet_length = skb->len - (2 * KALMIA_HEADER_LENGTH);
 282                 ether_packet_length = get_unaligned_le16(&header_start[2]);
 283                 skb_pull(skb, KALMIA_HEADER_LENGTH);
 284
 285                 /* Some small packets misses end marker */
 286                 if (usb_packet_length < ether_packet_length) {
 287                         ether_packet_length = usb_packet_length
 288                                 + KALMIA_HEADER_LENGTH;
 289                         is_last = true;
 290                 }
 291                 else {
 292                         netdev_dbg(dev->net, "Correct package length #%i", i
 293                                 + 1);
 294
 295                         is_last = (memcmp(skb->data + ether_packet_length,
 296                                 HEADER_END_OF_USB_PACKET,
 297                                 sizeof(HEADER_END_OF_USB_PACKET)) == 0);
 298                         if (!is_last) {
 299                                 header_start = skb->data + ether_packet_length;
 300                                 netdev_dbg(dev->net,
 301                                         "End header: %6phC. Package length: %i\n",
 302                                         header_start,
 303                                         skb->len - KALMIA_HEADER_LENGTH);
 304                         }
 305                 }
 306
 307                 if (is_last) {
 308                         skb2 = skb;
 309                 }
 310                 else {
 311                         skb2 = skb_clone(skb, GFP_ATOMIC);
 312                         if (unlikely(!skb2))
 313                                 return 0;
 314                 }
 315
 316                 skb_trim(skb2, ether_packet_length);
 317
 318                 if (is_last) {
 319                         return 1;
 320                 }
 321                 else {
 322                         usbnet_skb_return(dev, skb2);
 323                         skb_pull(skb, ether_packet_length);
 324                 }
 325
 326                 i++;
 327         }
 328         while (skb->len);
 329
 330         return 1;
 331 }
 332
 333 static const struct driver_info kalmia_info = {
 334         .description = "Samsung Kalmia LTE USB dongle",
 335         .flags = FLAG_WWAN,
 336         .bind = kalmia_bind,
 337         .rx_fixup = kalmia_rx_fixup,
 338         .tx_fixup = kalmia_tx_fixup
 339 };
 340
 341 /*-------------------------------------------------------------------------*/
 342
 343 static const struct usb_device_id products[] = {
 344         /* The unswitched USB ID, to get the module auto loaded: */
 345         { USB_DEVICE(0x04e8, 0x689a) },
 346         /* The stick switched into modem (by e.g. usb_modeswitch): */
 347         { USB_DEVICE(0x04e8, 0x6889),
 348                 .driver_info = (unsigned long) &kalmia_info, },
 349         { /* EMPTY == end of list */} };
 350 MODULE_DEVICE_TABLE( usb, products);
 351
 352 static struct usb_driver kalmia_driver = {
 353         .name = "kalmia",
 354         .id_table = products,
 355         .probe = usbnet_probe,
 356         .disconnect = usbnet_disconnect,
 357         .suspend = usbnet_suspend,
 358         .resume = usbnet_resume,
 359         .disable_hub_initiated_lpm = 1,
 360 };
 361
 362 module_usb_driver(kalmia_driver);
 363
 364 MODULE_AUTHOR("Marius Bjoernstad Kotsbak <marius@kotsbak.com>");
 365 MODULE_DESCRIPTION("Samsung Kalmia USB network driver");
 366 MODULE_LICENSE("GPL");