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"); 368