Linux Kernel  3.7.1
 All Data Structures Namespaces Files Functions Variables Typedefs Enumerations Enumerator Macros Groups Pages
kalmia.c
Go to the documentation of this file.
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 <[email protected]>
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  memcpy(dev->net->perm_addr, ethernet_addr, ETH_ALEN);
163 
164  return status;
165 }
166 
167 static struct sk_buff *
168 kalmia_tx_fixup(struct usbnet *dev, struct sk_buff *skb, gfp_t flags)
169 {
170  struct sk_buff *skb2 = NULL;
171  u16 content_len;
172  unsigned char *header_start;
173  unsigned char ether_type_1, ether_type_2;
174  u8 remainder, padlen = 0;
175 
176  if (!skb_cloned(skb)) {
177  int headroom = skb_headroom(skb);
178  int tailroom = skb_tailroom(skb);
179 
180  if ((tailroom >= KALMIA_ALIGN_SIZE) && (headroom
181  >= KALMIA_HEADER_LENGTH))
182  goto done;
183 
184  if ((headroom + tailroom) > (KALMIA_HEADER_LENGTH
185  + KALMIA_ALIGN_SIZE)) {
186  skb->data = memmove(skb->head + KALMIA_HEADER_LENGTH,
187  skb->data, skb->len);
188  skb_set_tail_pointer(skb, skb->len);
189  goto done;
190  }
191  }
192 
193  skb2 = skb_copy_expand(skb, KALMIA_HEADER_LENGTH,
194  KALMIA_ALIGN_SIZE, flags);
195  if (!skb2)
196  return NULL;
197 
198  dev_kfree_skb_any(skb);
199  skb = skb2;
200 
201 done:
202  header_start = skb_push(skb, KALMIA_HEADER_LENGTH);
203  ether_type_1 = header_start[KALMIA_HEADER_LENGTH + 12];
204  ether_type_2 = header_start[KALMIA_HEADER_LENGTH + 13];
205 
206  netdev_dbg(dev->net, "Sending etherType: %02x%02x", ether_type_1,
207  ether_type_2);
208 
209  /* According to empiric data for data packages */
210  header_start[0] = 0x57;
211  header_start[1] = 0x44;
212  content_len = skb->len - KALMIA_HEADER_LENGTH;
213 
214  put_unaligned_le16(content_len, &header_start[2]);
215  header_start[4] = ether_type_1;
216  header_start[5] = ether_type_2;
217 
218  /* Align to 4 bytes by padding with zeros */
219  remainder = skb->len % KALMIA_ALIGN_SIZE;
220  if (remainder > 0) {
221  padlen = KALMIA_ALIGN_SIZE - remainder;
222  memset(skb_put(skb, padlen), 0, padlen);
223  }
224 
225  netdev_dbg(
226  dev->net,
227  "Sending package with length %i and padding %i. Header: %02x:%02x:%02x:%02x:%02x:%02x.",
228  content_len, padlen, header_start[0], header_start[1],
229  header_start[2], header_start[3], header_start[4],
230  header_start[5]);
231 
232  return skb;
233 }
234 
235 static int
236 kalmia_rx_fixup(struct usbnet *dev, struct sk_buff *skb)
237 {
238  /*
239  * Our task here is to strip off framing, leaving skb with one
240  * data frame for the usbnet framework code to process.
241  */
242  static const u8 HEADER_END_OF_USB_PACKET[] =
243  { 0x57, 0x5a, 0x00, 0x00, 0x08, 0x00 };
244  static const u8 EXPECTED_UNKNOWN_HEADER_1[] =
245  { 0x57, 0x43, 0x1e, 0x00, 0x15, 0x02 };
246  static const u8 EXPECTED_UNKNOWN_HEADER_2[] =
247  { 0x57, 0x50, 0x0e, 0x00, 0x00, 0x00 };
248  int i = 0;
249 
250  /* incomplete header? */
251  if (skb->len < KALMIA_HEADER_LENGTH)
252  return 0;
253 
254  do {
255  struct sk_buff *skb2 = NULL;
256  u8 *header_start;
257  u16 usb_packet_length, ether_packet_length;
258  int is_last;
259 
260  header_start = skb->data;
261 
262  if (unlikely(header_start[0] != 0x57 || header_start[1] != 0x44)) {
263  if (!memcmp(header_start, EXPECTED_UNKNOWN_HEADER_1,
264  sizeof(EXPECTED_UNKNOWN_HEADER_1)) || !memcmp(
265  header_start, EXPECTED_UNKNOWN_HEADER_2,
266  sizeof(EXPECTED_UNKNOWN_HEADER_2))) {
267  netdev_dbg(
268  dev->net,
269  "Received expected unknown frame header: %02x:%02x:%02x:%02x:%02x:%02x. Package length: %i\n",
270  header_start[0], header_start[1],
271  header_start[2], header_start[3],
272  header_start[4], header_start[5],
273  skb->len - KALMIA_HEADER_LENGTH);
274  }
275  else {
276  netdev_err(
277  dev->net,
278  "Received unknown frame header: %02x:%02x:%02x:%02x:%02x:%02x. Package length: %i\n",
279  header_start[0], header_start[1],
280  header_start[2], header_start[3],
281  header_start[4], header_start[5],
282  skb->len - KALMIA_HEADER_LENGTH);
283  return 0;
284  }
285  }
286  else
287  netdev_dbg(
288  dev->net,
289  "Received header: %02x:%02x:%02x:%02x:%02x:%02x. Package length: %i\n",
290  header_start[0], header_start[1], header_start[2],
291  header_start[3], header_start[4], header_start[5],
292  skb->len - KALMIA_HEADER_LENGTH);
293 
294  /* subtract start header and end header */
295  usb_packet_length = skb->len - (2 * KALMIA_HEADER_LENGTH);
296  ether_packet_length = get_unaligned_le16(&header_start[2]);
297  skb_pull(skb, KALMIA_HEADER_LENGTH);
298 
299  /* Some small packets misses end marker */
300  if (usb_packet_length < ether_packet_length) {
301  ether_packet_length = usb_packet_length
302  + KALMIA_HEADER_LENGTH;
303  is_last = true;
304  }
305  else {
306  netdev_dbg(dev->net, "Correct package length #%i", i
307  + 1);
308 
309  is_last = (memcmp(skb->data + ether_packet_length,
310  HEADER_END_OF_USB_PACKET,
311  sizeof(HEADER_END_OF_USB_PACKET)) == 0);
312  if (!is_last) {
313  header_start = skb->data + ether_packet_length;
314  netdev_dbg(
315  dev->net,
316  "End header: %02x:%02x:%02x:%02x:%02x:%02x. Package length: %i\n",
317  header_start[0], header_start[1],
318  header_start[2], header_start[3],
319  header_start[4], header_start[5],
320  skb->len - KALMIA_HEADER_LENGTH);
321  }
322  }
323 
324  if (is_last) {
325  skb2 = skb;
326  }
327  else {
328  skb2 = skb_clone(skb, GFP_ATOMIC);
329  if (unlikely(!skb2))
330  return 0;
331  }
332 
333  skb_trim(skb2, ether_packet_length);
334 
335  if (is_last) {
336  return 1;
337  }
338  else {
339  usbnet_skb_return(dev, skb2);
340  skb_pull(skb, ether_packet_length);
341  }
342 
343  i++;
344  }
345  while (skb->len);
346 
347  return 1;
348 }
349 
350 static const struct driver_info kalmia_info = {
351  .description = "Samsung Kalmia LTE USB dongle",
352  .flags = FLAG_WWAN,
353  .bind = kalmia_bind,
354  .rx_fixup = kalmia_rx_fixup,
355  .tx_fixup = kalmia_tx_fixup
356 };
357 
358 /*-------------------------------------------------------------------------*/
359 
360 static const struct usb_device_id products[] = {
361  /* The unswitched USB ID, to get the module auto loaded: */
362  { USB_DEVICE(0x04e8, 0x689a) },
363  /* The stick swithed into modem (by e.g. usb_modeswitch): */
364  { USB_DEVICE(0x04e8, 0x6889),
365  .driver_info = (unsigned long) &kalmia_info, },
366  { /* EMPTY == end of list */} };
367 MODULE_DEVICE_TABLE( usb, products);
368 
369 static struct usb_driver kalmia_driver = {
370  .name = "kalmia",
371  .id_table = products,
372  .probe = usbnet_probe,
373  .disconnect = usbnet_disconnect,
374  .suspend = usbnet_suspend,
375  .resume = usbnet_resume,
376  .disable_hub_initiated_lpm = 1,
377 };
378 
379 module_usb_driver(kalmia_driver);
380 
381 MODULE_AUTHOR("Marius Bjoernstad Kotsbak <[email protected]>");
382 MODULE_DESCRIPTION("Samsung Kalmia USB network driver");
383 MODULE_LICENSE("GPL");
Generated on Thu Jan 10 2013 14:07:37 for Linux Kernel by   doxygen 1.8.2