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         static const char init_msg_1[] =
 104                 { 0x57, 0x50, 0x04, 0x00, 0x00, 0x00, 0x00, 0x20, 0x00, 0x00,
 105                 0x00, 0x00 };
 106         static const char init_msg_2[] =
 107                 { 0x57, 0x50, 0x04, 0x00, 0x00, 0x00, 0x00, 0x02, 0x00, 0xf4,
 108                 0x00, 0x00 };
 109         static const int buflen = 28;
 110         char *usb_buf;
 111         int status;
 112
 113         usb_buf = kmalloc(buflen, GFP_DMA | GFP_KERNEL);
 114         if (!usb_buf)
 115                 return -ENOMEM;
 116
 117         memcpy(usb_buf, init_msg_1, 12);
 118         status = kalmia_send_init_packet(dev, usb_buf, sizeof(init_msg_1)
 119                 / sizeof(init_msg_1[0]), usb_buf, 24);
 120         if (status != 0)
 121                 return status;
 122
 123         memcpy(usb_buf, init_msg_2, 12);
 124         status = kalmia_send_init_packet(dev, usb_buf, sizeof(init_msg_2)
 125                 / sizeof(init_msg_2[0]), usb_buf, 28);
 126         if (status != 0)
 127                 return status;
 128
 129         memcpy(ethernet_addr, usb_buf + 10, ETH_ALEN);
 130
 131         kfree(usb_buf);
 132         return status;
 133 }
 134
 135 static int
 136 kalmia_bind(struct usbnet *dev, struct usb_interface *intf)
 137 {
 138         int status;
 139         u8 ethernet_addr[ETH_ALEN];
 140
 141         /* Don't bind to AT command interface */
 142         if (intf->cur_altsetting->desc.bInterfaceClass != USB_CLASS_VENDOR_SPEC)
 143                 return -EINVAL;
 144
 145         dev->in = usb_rcvbulkpipe(dev->udev, 0x81 & USB_ENDPOINT_NUMBER_MASK);
 146         dev->out = usb_sndbulkpipe(dev->udev, 0x02 & USB_ENDPOINT_NUMBER_MASK);
 147         dev->status = NULL;
 148
 149         dev->net->hard_header_len += KALMIA_HEADER_LENGTH;
 150         dev->hard_mtu = 1400;
 151         dev->rx_urb_size = dev->hard_mtu * 10; // Found as optimal after testing
 152
 153         status = kalmia_init_and_get_ethernet_addr(dev, ethernet_addr);
 154
 155         if (status < 0) {
 156                 usb_set_intfdata(intf, NULL);
 157                 usb_driver_release_interface(driver_of(intf), intf);
 158                 return status;
 159         }
 160
 161         memcpy(dev->net->dev_addr, ethernet_addr, ETH_ALEN);
 162
 163         return status;
 164 }
 165
 166 static struct sk_buff *
 167 kalmia_tx_fixup(struct usbnet *dev, struct sk_buff *skb, gfp_t flags)
 168 {
 169         struct sk_buff *skb2 = NULL;
 170         u16 content_len;
 171         unsigned char *header_start;
 172         unsigned char ether_type_1, ether_type_2;
 173         u8 remainder, padlen = 0;
 174
 175         if (!skb_cloned(skb)) {
 176                 int headroom = skb_headroom(skb);
 177                 int tailroom = skb_tailroom(skb);
 178
 179                 if ((tailroom >= KALMIA_ALIGN_SIZE) && (headroom
 180                         >= KALMIA_HEADER_LENGTH))
 181                         goto done;
 182
 183                 if ((headroom + tailroom) > (KALMIA_HEADER_LENGTH
 184                         + KALMIA_ALIGN_SIZE)) {
 185                         skb->data = memmove(skb->head + KALMIA_HEADER_LENGTH,
 186                                 skb->data, skb->len);
 187                         skb_set_tail_pointer(skb, skb->len);
 188                         goto done;
 189                 }
 190         }
 191
 192         skb2 = skb_copy_expand(skb, KALMIA_HEADER_LENGTH,
 193                 KALMIA_ALIGN_SIZE, flags);
 194         if (!skb2)
 195                 return NULL;
 196
 197         dev_kfree_skb_any(skb);
 198         skb = skb2;
 199
 200 done:
 201         header_start = skb_push(skb, KALMIA_HEADER_LENGTH);
 202         ether_type_1 = header_start[KALMIA_HEADER_LENGTH + 12];
 203         ether_type_2 = header_start[KALMIA_HEADER_LENGTH + 13];
 204
 205         netdev_dbg(dev->net, "Sending etherType: %02x%02x", ether_type_1,
 206                 ether_type_2);
 207
 208         /* According to empiric data for data packages */
 209         header_start[0] = 0x57;
 210         header_start[1] = 0x44;
 211         content_len = skb->len - KALMIA_HEADER_LENGTH;
 212
 213         put_unaligned_le16(content_len, &header_start[2]);
 214         header_start[4] = ether_type_1;
 215         header_start[5] = ether_type_2;
 216
 217         /* Align to 4 bytes by padding with zeros */
 218         remainder = skb->len % KALMIA_ALIGN_SIZE;
 219         if (remainder > 0) {
 220                 padlen = KALMIA_ALIGN_SIZE - remainder;
 221                 memset(skb_put(skb, padlen), 0, padlen);
 222         }
 223
 224         netdev_dbg(dev->net,
 225                 "Sending package with length %i and padding %i. Header: %6phC.",
 226                 content_len, padlen, header_start);
 227
 228         return skb;
 229 }
 230
 231 static int
 232 kalmia_rx_fixup(struct usbnet *dev, struct sk_buff *skb)
 233 {
 234         /*
 235          * Our task here is to strip off framing, leaving skb with one
 236          * data frame for the usbnet framework code to process.
 237          */
 238         static const u8 HEADER_END_OF_USB_PACKET[] =
 239                 { 0x57, 0x5a, 0x00, 0x00, 0x08, 0x00 };
 240         static const u8 EXPECTED_UNKNOWN_HEADER_1[] =
 241                 { 0x57, 0x43, 0x1e, 0x00, 0x15, 0x02 };
 242         static const u8 EXPECTED_UNKNOWN_HEADER_2[] =
 243                 { 0x57, 0x50, 0x0e, 0x00, 0x00, 0x00 };
 244         int i = 0;
 245
 246         /* incomplete header? */
 247         if (skb->len < KALMIA_HEADER_LENGTH)
 248                 return 0;
 249
 250         do {
 251                 struct sk_buff *skb2 = NULL;
 252                 u8 *header_start;
 253                 u16 usb_packet_length, ether_packet_length;
 254                 int is_last;
 255
 256                 header_start = skb->data;
 257
 258                 if (unlikely(header_start[0] != 0x57 || header_start[1] != 0x44)) {
 259                         if (!memcmp(header_start, EXPECTED_UNKNOWN_HEADER_1,
 260                                 sizeof(EXPECTED_UNKNOWN_HEADER_1)) || !memcmp(
 261                                 header_start, EXPECTED_UNKNOWN_HEADER_2,
 262                                 sizeof(EXPECTED_UNKNOWN_HEADER_2))) {
 263                                 netdev_dbg(dev->net,
 264                                         "Received expected unknown frame header: %6phC. Package length: %i\n",
 265                                         header_start,
 266                                         skb->len - KALMIA_HEADER_LENGTH);
 267                         }
 268                         else {
 269                                 netdev_err(dev->net,
 270                                         "Received unknown frame header: %6phC. Package length: %i\n",
 271                                         header_start,
 272                                         skb->len - KALMIA_HEADER_LENGTH);
 273                                 return 0;
 274                         }
 275                 }
 276                 else
 277                         netdev_dbg(dev->net,
 278                                 "Received header: %6phC. Package length: %i\n",
 279                                 header_start, skb->len - KALMIA_HEADER_LENGTH);
 280
 281                 /* subtract start header and end header */
 282                 usb_packet_length = skb->len - (2 * KALMIA_HEADER_LENGTH);
 283                 ether_packet_length = get_unaligned_le16(&header_start[2]);
 284                 skb_pull(skb, KALMIA_HEADER_LENGTH);
 285
 286                 /* Some small packets misses end marker */
 287                 if (usb_packet_length < ether_packet_length) {
 288                         ether_packet_length = usb_packet_length
 289                                 + KALMIA_HEADER_LENGTH;
 290                         is_last = true;
 291                 }
 292                 else {
 293                         netdev_dbg(dev->net, "Correct package length #%i", i
 294                                 + 1);
 295
 296                         is_last = (memcmp(skb->data + ether_packet_length,
 297                                 HEADER_END_OF_USB_PACKET,
 298                                 sizeof(HEADER_END_OF_USB_PACKET)) == 0);
 299                         if (!is_last) {
 300                                 header_start = skb->data + ether_packet_length;
 301                                 netdev_dbg(dev->net,
 302                                         "End header: %6phC. Package length: %i\n",
 303                                         header_start,
 304                                         skb->len - KALMIA_HEADER_LENGTH);
 305                         }
 306                 }
 307
 308                 if (is_last) {
 309                         skb2 = skb;
 310                 }
 311                 else {
 312                         skb2 = skb_clone(skb, GFP_ATOMIC);
 313                         if (unlikely(!skb2))
 314                                 return 0;
 315                 }
 316
 317                 skb_trim(skb2, ether_packet_length);
 318
 319                 if (is_last) {
 320                         return 1;
 321                 }
 322                 else {
 323                         usbnet_skb_return(dev, skb2);
 324                         skb_pull(skb, ether_packet_length);
 325                 }
 326
 327                 i++;
 328         }
 329         while (skb->len);
 330
 331         return 1;
 332 }
 333
 334 static const struct driver_info kalmia_info = {
 335         .description = "Samsung Kalmia LTE USB dongle",
 336         .flags = FLAG_WWAN,
 337         .bind = kalmia_bind,
 338         .rx_fixup = kalmia_rx_fixup,
 339         .tx_fixup = kalmia_tx_fixup
 340 };
 341
 342 /*-------------------------------------------------------------------------*/
 343
 344 static const struct usb_device_id products[] = {
 345         /* The unswitched USB ID, to get the module auto loaded: */
 346         { USB_DEVICE(0x04e8, 0x689a) },
 347         /* The stick swithed into modem (by e.g. usb_modeswitch): */
 348         { USB_DEVICE(0x04e8, 0x6889),
 349                 .driver_info = (unsigned long) &kalmia_info, },
 350         { /* EMPTY == end of list */} };
 351 MODULE_DEVICE_TABLE( usb, products);
 352
 353 static struct usb_driver kalmia_driver = {
 354         .name = "kalmia",
 355         .id_table = products,
 356         .probe = usbnet_probe,
 357         .disconnect = usbnet_disconnect,
 358         .suspend = usbnet_suspend,
 359         .resume = usbnet_resume,
 360         .disable_hub_initiated_lpm = 1,
 361 };
 362
 363 module_usb_driver(kalmia_driver);
 364
 365 MODULE_AUTHOR("Marius Bjoernstad Kotsbak <marius@kotsbak.com>");
 366 MODULE_DESCRIPTION("Samsung Kalmia USB network driver");
 367 MODULE_LICENSE("GPL");