Omar Laazimani | 9f722c0 | 2009-05-04 12:01:43 -0700 | [diff] [blame] | 1 | /* |
| 2 | * USB CDC EEM network interface driver |
| 3 | * Copyright (C) 2009 Oberthur Technologies |
| 4 | * by Omar Laazimani, Olivier Condemine |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or modify |
| 7 | * it under the terms of the GNU General Public License as published by |
| 8 | * the Free Software Foundation; either version 2 of the License, or |
| 9 | * (at your option) any later version. |
| 10 | * |
| 11 | * This program is distributed in the hope that it will be useful, |
| 12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 14 | * GNU General Public License for more details. |
| 15 | * |
| 16 | * You should have received a copy of the GNU General Public License |
| 17 | * along with this program; if not, write to the Free Software |
| 18 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
| 19 | */ |
| 20 | |
| 21 | #include <linux/module.h> |
| 22 | #include <linux/init.h> |
| 23 | #include <linux/netdevice.h> |
| 24 | #include <linux/etherdevice.h> |
| 25 | #include <linux/ctype.h> |
| 26 | #include <linux/ethtool.h> |
| 27 | #include <linux/workqueue.h> |
| 28 | #include <linux/mii.h> |
| 29 | #include <linux/usb.h> |
| 30 | #include <linux/crc32.h> |
| 31 | #include <linux/usb/cdc.h> |
| 32 | #include <linux/usb/usbnet.h> |
| 33 | |
| 34 | |
| 35 | /* |
| 36 | * This driver is an implementation of the CDC "Ethernet Emulation |
| 37 | * Model" (EEM) specification, which encapsulates Ethernet frames |
| 38 | * for transport over USB using a simpler USB device model than the |
| 39 | * previous CDC "Ethernet Control Model" (ECM, or "CDC Ethernet"). |
| 40 | * |
| 41 | * For details, see www.usb.org/developers/devclass_docs/CDC_EEM10.pdf |
| 42 | * |
| 43 | * This version has been tested with GIGAntIC WuaoW SIM Smart Card on 2.6.24, |
| 44 | * 2.6.27 and 2.6.30rc2 kernel. |
| 45 | * It has also been validated on Openmoko Om 2008.12 (based on 2.6.24 kernel). |
| 46 | * build on 23-April-2009 |
| 47 | */ |
| 48 | |
| 49 | #define EEM_HEAD 2 /* 2 byte header */ |
| 50 | |
| 51 | /*-------------------------------------------------------------------------*/ |
| 52 | |
| 53 | static void eem_linkcmd_complete(struct urb *urb) |
| 54 | { |
| 55 | dev_kfree_skb(urb->context); |
| 56 | usb_free_urb(urb); |
| 57 | } |
| 58 | |
| 59 | static void eem_linkcmd(struct usbnet *dev, struct sk_buff *skb) |
| 60 | { |
| 61 | struct urb *urb; |
| 62 | int status; |
| 63 | |
| 64 | urb = usb_alloc_urb(0, GFP_ATOMIC); |
| 65 | if (!urb) |
| 66 | goto fail; |
| 67 | |
| 68 | usb_fill_bulk_urb(urb, dev->udev, dev->out, |
| 69 | skb->data, skb->len, eem_linkcmd_complete, skb); |
| 70 | |
| 71 | status = usb_submit_urb(urb, GFP_ATOMIC); |
| 72 | if (status) { |
| 73 | usb_free_urb(urb); |
| 74 | fail: |
| 75 | dev_kfree_skb(skb); |
| 76 | devwarn(dev, "link cmd failure\n"); |
| 77 | return; |
| 78 | } |
| 79 | } |
| 80 | |
| 81 | static int eem_bind(struct usbnet *dev, struct usb_interface *intf) |
| 82 | { |
| 83 | int status = 0; |
| 84 | |
| 85 | status = usbnet_get_endpoints(dev, intf); |
| 86 | if (status < 0) { |
| 87 | usb_set_intfdata(intf, NULL); |
| 88 | usb_driver_release_interface(driver_of(intf), intf); |
| 89 | return status; |
| 90 | } |
| 91 | |
| 92 | /* no jumbogram (16K) support for now */ |
| 93 | |
| 94 | dev->net->hard_header_len += EEM_HEAD + ETH_FCS_LEN; |
| 95 | |
| 96 | return 0; |
| 97 | } |
| 98 | |
| 99 | /* |
| 100 | * EEM permits packing multiple Ethernet frames into USB transfers |
| 101 | * (a "bundle"), but for TX we don't try to do that. |
| 102 | */ |
| 103 | static struct sk_buff *eem_tx_fixup(struct usbnet *dev, struct sk_buff *skb, |
| 104 | gfp_t flags) |
| 105 | { |
| 106 | struct sk_buff *skb2 = NULL; |
| 107 | u16 len = skb->len; |
| 108 | u32 crc = 0; |
| 109 | int padlen = 0; |
| 110 | |
| 111 | /* When ((len + EEM_HEAD + ETH_FCS_LEN) % dev->maxpacket) is |
| 112 | * zero, stick two bytes of zero length EEM packet on the end. |
| 113 | * Else the framework would add invalid single byte padding, |
| 114 | * since it can't know whether ZLPs will be handled right by |
| 115 | * all the relevant hardware and software. |
| 116 | */ |
| 117 | if (!((len + EEM_HEAD + ETH_FCS_LEN) % dev->maxpacket)) |
| 118 | padlen += 2; |
| 119 | |
| 120 | if (!skb_cloned(skb)) { |
| 121 | int headroom = skb_headroom(skb); |
| 122 | int tailroom = skb_tailroom(skb); |
| 123 | |
| 124 | if ((tailroom >= ETH_FCS_LEN + padlen) |
| 125 | && (headroom >= EEM_HEAD)) |
| 126 | goto done; |
| 127 | |
| 128 | if ((headroom + tailroom) |
| 129 | > (EEM_HEAD + ETH_FCS_LEN + padlen)) { |
| 130 | skb->data = memmove(skb->head + |
| 131 | EEM_HEAD, |
| 132 | skb->data, |
| 133 | skb->len); |
| 134 | skb_set_tail_pointer(skb, len); |
| 135 | goto done; |
| 136 | } |
| 137 | } |
| 138 | |
| 139 | skb2 = skb_copy_expand(skb, EEM_HEAD, ETH_FCS_LEN + padlen, flags); |
| 140 | if (!skb2) |
| 141 | return NULL; |
| 142 | |
| 143 | dev_kfree_skb_any(skb); |
| 144 | skb = skb2; |
| 145 | |
| 146 | done: |
| 147 | /* we don't use the "no Ethernet CRC" option */ |
| 148 | crc = crc32_le(~0, skb->data, skb->len); |
| 149 | crc = ~crc; |
| 150 | |
| 151 | put_unaligned_le32(crc, skb_put(skb, 4)); |
| 152 | |
| 153 | /* EEM packet header format: |
| 154 | * b0..13: length of ethernet frame |
| 155 | * b14: bmCRC (1 == valid Ethernet CRC) |
| 156 | * b15: bmType (0 == data) |
| 157 | */ |
| 158 | len = skb->len; |
| 159 | put_unaligned_le16(BIT(14) | len, skb_push(skb, 2)); |
| 160 | |
| 161 | /* Bundle a zero length EEM packet if needed */ |
| 162 | if (padlen) |
| 163 | put_unaligned_le16(0, skb_put(skb, 2)); |
| 164 | |
| 165 | return skb; |
| 166 | } |
| 167 | |
| 168 | static int eem_rx_fixup(struct usbnet *dev, struct sk_buff *skb) |
| 169 | { |
| 170 | /* |
| 171 | * Our task here is to strip off framing, leaving skb with one |
| 172 | * data frame for the usbnet framework code to process. But we |
| 173 | * may have received multiple EEM payloads, or command payloads. |
| 174 | * So we must process _everything_ as if it's a header, except |
| 175 | * maybe the last data payload |
| 176 | * |
| 177 | * REVISIT the framework needs updating so that when we consume |
| 178 | * all payloads (the last or only message was a command, or a |
| 179 | * zero length EEM packet) that is not accounted as an rx_error. |
| 180 | */ |
| 181 | do { |
| 182 | struct sk_buff *skb2 = NULL; |
| 183 | u16 header; |
| 184 | u16 len = 0; |
| 185 | |
| 186 | /* incomplete EEM header? */ |
| 187 | if (skb->len < EEM_HEAD) |
| 188 | return 0; |
| 189 | |
| 190 | /* |
| 191 | * EEM packet header format: |
| 192 | * b0..14: EEM type dependant (Data or Command) |
| 193 | * b15: bmType |
| 194 | */ |
| 195 | header = get_unaligned_le16(skb->data); |
| 196 | skb_pull(skb, EEM_HEAD); |
| 197 | |
| 198 | /* |
| 199 | * The bmType bit helps to denote when EEM |
| 200 | * packet is data or command : |
| 201 | * bmType = 0 : EEM data payload |
| 202 | * bmType = 1 : EEM (link) command |
| 203 | */ |
| 204 | if (header & BIT(15)) { |
| 205 | u16 bmEEMCmd; |
| 206 | |
| 207 | /* |
| 208 | * EEM (link) command packet: |
| 209 | * b0..10: bmEEMCmdParam |
| 210 | * b11..13: bmEEMCmd |
| 211 | * b14: bmReserved (must be 0) |
| 212 | * b15: 1 (EEM command) |
| 213 | */ |
| 214 | if (header & BIT(14)) { |
| 215 | devdbg(dev, "reserved command %04x\n", header); |
| 216 | continue; |
| 217 | } |
| 218 | |
| 219 | bmEEMCmd = (header >> 11) & 0x7; |
| 220 | switch (bmEEMCmd) { |
| 221 | |
| 222 | /* Responding to echo requests is mandatory. */ |
| 223 | case 0: /* Echo command */ |
| 224 | len = header & 0x7FF; |
| 225 | |
| 226 | /* bogus command? */ |
| 227 | if (skb->len < len) |
| 228 | return 0; |
| 229 | |
| 230 | skb2 = skb_clone(skb, GFP_ATOMIC); |
| 231 | if (unlikely(!skb2)) |
| 232 | goto next; |
| 233 | skb_trim(skb2, len); |
| 234 | put_unaligned_le16(BIT(15) | (1 << 11) | len, |
| 235 | skb_push(skb2, 2)); |
| 236 | eem_linkcmd(dev, skb2); |
| 237 | break; |
| 238 | |
| 239 | /* |
| 240 | * Host may choose to ignore hints. |
| 241 | * - suspend: peripheral ready to suspend |
| 242 | * - response: suggest N millisec polling |
| 243 | * - response complete: suggest N sec polling |
| 244 | */ |
| 245 | case 2: /* Suspend hint */ |
| 246 | case 3: /* Response hint */ |
| 247 | case 4: /* Response complete hint */ |
| 248 | continue; |
| 249 | |
| 250 | /* |
| 251 | * Hosts should never receive host-to-peripheral |
| 252 | * or reserved command codes; or responses to an |
| 253 | * echo command we didn't send. |
| 254 | */ |
| 255 | case 1: /* Echo response */ |
| 256 | case 5: /* Tickle */ |
| 257 | default: /* reserved */ |
| 258 | devwarn(dev, "unexpected link command %d\n", |
| 259 | bmEEMCmd); |
| 260 | continue; |
| 261 | } |
| 262 | |
| 263 | } else { |
| 264 | u32 crc, crc2; |
| 265 | int is_last; |
| 266 | |
| 267 | /* zero length EEM packet? */ |
| 268 | if (header == 0) |
| 269 | continue; |
| 270 | |
| 271 | /* |
| 272 | * EEM data packet header : |
| 273 | * b0..13: length of ethernet frame |
| 274 | * b14: bmCRC |
| 275 | * b15: 0 (EEM data) |
| 276 | */ |
| 277 | len = header & 0x3FFF; |
| 278 | |
| 279 | /* bogus EEM payload? */ |
| 280 | if (skb->len < len) |
| 281 | return 0; |
| 282 | |
| 283 | /* bogus ethernet frame? */ |
| 284 | if (len < (ETH_HLEN + ETH_FCS_LEN)) |
| 285 | goto next; |
| 286 | |
| 287 | /* |
| 288 | * Treat the last payload differently: framework |
| 289 | * code expects our "fixup" to have stripped off |
| 290 | * headers, so "skb" is a data packet (or error). |
| 291 | * Else if it's not the last payload, keep "skb" |
| 292 | * for further processing. |
| 293 | */ |
| 294 | is_last = (len == skb->len); |
| 295 | if (is_last) |
| 296 | skb2 = skb; |
| 297 | else { |
| 298 | skb2 = skb_clone(skb, GFP_ATOMIC); |
| 299 | if (unlikely(!skb2)) |
| 300 | return 0; |
| 301 | } |
| 302 | |
| 303 | crc = get_unaligned_le32(skb2->data |
| 304 | + len - ETH_FCS_LEN); |
| 305 | skb_trim(skb2, len - ETH_FCS_LEN); |
| 306 | |
| 307 | /* |
| 308 | * The bmCRC helps to denote when the CRC field in |
| 309 | * the Ethernet frame contains a calculated CRC: |
| 310 | * bmCRC = 1 : CRC is calculated |
| 311 | * bmCRC = 0 : CRC = 0xDEADBEEF |
| 312 | */ |
| 313 | if (header & BIT(14)) |
Vincent CUISSARD | 7fefe6a | 2009-07-16 06:08:58 +0000 | [diff] [blame] | 314 | crc2 = ~crc32_le(~0, skb2->data, skb2->len); |
Omar Laazimani | 9f722c0 | 2009-05-04 12:01:43 -0700 | [diff] [blame] | 315 | else |
| 316 | crc2 = 0xdeadbeef; |
| 317 | |
| 318 | if (is_last) |
| 319 | return crc == crc2; |
| 320 | |
| 321 | if (unlikely(crc != crc2)) { |
Herbert Xu | eaea43a | 2009-06-29 16:49:40 +0000 | [diff] [blame] | 322 | dev->net->stats.rx_errors++; |
Omar Laazimani | 9f722c0 | 2009-05-04 12:01:43 -0700 | [diff] [blame] | 323 | dev_kfree_skb_any(skb2); |
| 324 | } else |
| 325 | usbnet_skb_return(dev, skb2); |
| 326 | } |
| 327 | |
| 328 | next: |
| 329 | skb_pull(skb, len); |
| 330 | } while (skb->len); |
| 331 | |
| 332 | return 1; |
| 333 | } |
| 334 | |
| 335 | static const struct driver_info eem_info = { |
| 336 | .description = "CDC EEM Device", |
| 337 | .flags = FLAG_ETHER, |
| 338 | .bind = eem_bind, |
| 339 | .rx_fixup = eem_rx_fixup, |
| 340 | .tx_fixup = eem_tx_fixup, |
| 341 | }; |
| 342 | |
| 343 | /*-------------------------------------------------------------------------*/ |
| 344 | |
| 345 | static const struct usb_device_id products[] = { |
| 346 | { |
| 347 | USB_INTERFACE_INFO(USB_CLASS_COMM, USB_CDC_SUBCLASS_EEM, |
| 348 | USB_CDC_PROTO_EEM), |
| 349 | .driver_info = (unsigned long) &eem_info, |
| 350 | }, |
| 351 | { |
| 352 | /* EMPTY == end of list */ |
| 353 | }, |
| 354 | }; |
| 355 | MODULE_DEVICE_TABLE(usb, products); |
| 356 | |
| 357 | static struct usb_driver eem_driver = { |
| 358 | .name = "cdc_eem", |
| 359 | .id_table = products, |
| 360 | .probe = usbnet_probe, |
| 361 | .disconnect = usbnet_disconnect, |
| 362 | .suspend = usbnet_suspend, |
| 363 | .resume = usbnet_resume, |
| 364 | }; |
| 365 | |
| 366 | |
| 367 | static int __init eem_init(void) |
| 368 | { |
| 369 | return usb_register(&eem_driver); |
| 370 | } |
| 371 | module_init(eem_init); |
| 372 | |
| 373 | static void __exit eem_exit(void) |
| 374 | { |
| 375 | usb_deregister(&eem_driver); |
| 376 | } |
| 377 | module_exit(eem_exit); |
| 378 | |
| 379 | MODULE_AUTHOR("Omar Laazimani <omar.oberthur@gmail.com>"); |
| 380 | MODULE_DESCRIPTION("USB CDC EEM"); |
| 381 | MODULE_LICENSE("GPL"); |