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Marius B. Kotsbakd4026122011-06-12 02:35:02 +00001/*
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
60static int
61kalmia_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
100static int
101kalmia_init_and_get_ethernet_addr(struct usbnet *dev, u8 *ethernet_addr)
102{
Jesper Juhlbd0d7aa2011-07-11 22:15:02 -0700103 static const char init_msg_1[] =
Marius B. Kotsbakd4026122011-06-12 02:35:02 +0000104 { 0x57, 0x50, 0x04, 0x00, 0x00, 0x00, 0x00, 0x20, 0x00, 0x00,
105 0x00, 0x00 };
Jesper Juhlbd0d7aa2011-07-11 22:15:02 -0700106 static const char init_msg_2[] =
Marius B. Kotsbakd4026122011-06-12 02:35:02 +0000107 { 0x57, 0x50, 0x04, 0x00, 0x00, 0x00, 0x00, 0x02, 0x00, 0xf4,
108 0x00, 0x00 };
Jesper Juhlbd0d7aa2011-07-11 22:15:02 -0700109 static const int buflen = 28;
Marius B. Kotsbak7cdfa4a2011-06-22 05:26:16 +0000110 char *usb_buf;
Marius B. Kotsbakd4026122011-06-12 02:35:02 +0000111 int status;
112
Marius B. Kotsbak7cdfa4a2011-06-22 05:26:16 +0000113 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);
Marius B. Kotsbakd4026122011-06-12 02:35:02 +0000120 if (status != 0)
121 return status;
122
Marius B. Kotsbak7cdfa4a2011-06-22 05:26:16 +0000123 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);
Marius B. Kotsbakd4026122011-06-12 02:35:02 +0000126 if (status != 0)
127 return status;
128
Marius B. Kotsbak7cdfa4a2011-06-22 05:26:16 +0000129 memcpy(ethernet_addr, usb_buf + 10, ETH_ALEN);
Marius B. Kotsbakd4026122011-06-12 02:35:02 +0000130
Marius B. Kotsbak7cdfa4a2011-06-22 05:26:16 +0000131 kfree(usb_buf);
Marius B. Kotsbakd4026122011-06-12 02:35:02 +0000132 return status;
133}
134
135static int
136kalmia_bind(struct usbnet *dev, struct usb_interface *intf)
137{
Dan Carpenter5c18e802011-06-23 03:15:39 -0700138 int status;
Marius B. Kotsbakd4026122011-06-12 02:35:02 +0000139 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
167static struct sk_buff *
168kalmia_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
Marius B. Kotsbak7cdfa4a2011-06-22 05:26:16 +0000201done:
202 header_start = skb_push(skb, KALMIA_HEADER_LENGTH);
Marius B. Kotsbakd4026122011-06-12 02:35:02 +0000203 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;
Marius B. Kotsbakd4026122011-06-12 02:35:02 +0000213
Marius B. Kotsbak7cdfa4a2011-06-22 05:26:16 +0000214 put_unaligned_le16(content_len, &header_start[2]);
Marius B. Kotsbakd4026122011-06-12 02:35:02 +0000215 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
235static int
236kalmia_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 */
Jesper Juhlbd0d7aa2011-07-11 22:15:02 -0700242 static const u8 HEADER_END_OF_USB_PACKET[] =
Marius B. Kotsbakd4026122011-06-12 02:35:02 +0000243 { 0x57, 0x5a, 0x00, 0x00, 0x08, 0x00 };
Jesper Juhlbd0d7aa2011-07-11 22:15:02 -0700244 static const u8 EXPECTED_UNKNOWN_HEADER_1[] =
Marius B. Kotsbakd4026122011-06-12 02:35:02 +0000245 { 0x57, 0x43, 0x1e, 0x00, 0x15, 0x02 };
Jesper Juhlbd0d7aa2011-07-11 22:15:02 -0700246 static const u8 EXPECTED_UNKNOWN_HEADER_2[] =
Marius B. Kotsbakd4026122011-06-12 02:35:02 +0000247 { 0x57, 0x50, 0x0e, 0x00, 0x00, 0x00 };
Marius B. Kotsbak7cdfa4a2011-06-22 05:26:16 +0000248 int i = 0;
Marius B. Kotsbakd4026122011-06-12 02:35:02 +0000249
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);
Marius B. Kotsbak7cdfa4a2011-06-22 05:26:16 +0000296 ether_packet_length = get_unaligned_le16(&header_start[2]);
Marius B. Kotsbakd4026122011-06-12 02:35:02 +0000297 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
350static 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
360static 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 */} };
367MODULE_DEVICE_TABLE( usb, products);
368
369static 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};
377
378static int __init kalmia_init(void)
379{
380 return usb_register(&kalmia_driver);
381}
382module_init( kalmia_init);
383
384static void __exit kalmia_exit(void)
385{
386 usb_deregister(&kalmia_driver);
387}
388module_exit( kalmia_exit);
389
390MODULE_AUTHOR("Marius Bjoernstad Kotsbak <marius@kotsbak.com>");
391MODULE_DESCRIPTION("Samsung Kalmia USB network driver");
392MODULE_LICENSE("GPL");