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 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 <marius@kotsbak.com>"); 382 MODULE_DESCRIPTION("Samsung Kalmia USB network driver"); 383 MODULE_LICENSE("GPL"); 384