LXR linux/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
  59static int
  60kalmia_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
  99static int
 100kalmia_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
 134static int
 135kalmia_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 < 0) {
 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
 165static struct sk_buff *
 166kalmia_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
 199done:
 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                memset(skb_put(skb, padlen), 0, 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
 230static int
 231kalmia_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
 333static 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
 343static 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 swithed into modem (by e.g. usb_modeswitch): */
 347        { USB_DEVICE(0x04e8, 0x6889),
 348                .driver_info = (unsigned long) &kalmia_info, },
 349        { /* EMPTY == end of list */} };
 350MODULE_DEVICE_TABLE( usb, products);
 351
 352static 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
 362module_usb_driver(kalmia_driver);
 363
 364MODULE_AUTHOR("Marius Bjoernstad Kotsbak <marius@kotsbak.com>");
 365MODULE_DESCRIPTION("Samsung Kalmia USB network driver");
 366MODULE_LICENSE("GPL");
 367