drivers/net/wimax/i2400m/netdev.c

   1 /*
   2  * Intel Wireless WiMAX Connection 2400m
   3  * Glue with the networking stack
   4  *
   5  *
   6  * Copyright (C) 2007 Intel Corporation <linux-wimax@intel.com>
   7  * Yanir Lubetkin <yanirx.lubetkin@intel.com>
   8  * Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>
   9  *
  10  * This program is free software; you can redistribute it and/or
  11  * modify it under the terms of the GNU General Public License version
  12  * 2 as published by the Free Software Foundation.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  * GNU General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License
  20  * along with this program; if not, write to the Free Software
  21  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  22  * 02110-1301, USA.
  23  *
  24  *
  25  * This implements an ethernet device for the i2400m.
  26  *
  27  * We fake being an ethernet device to simplify the support from user
  28  * space and from the other side. The world is (sadly) configured to
  29  * take in only Ethernet devices...
  30  *
  31  * Because of this, when using firmwares <= v1.3, there is an
  32  * copy-each-rxed-packet overhead on the RX path. Each IP packet has
  33  * to be reallocated to add an ethernet header (as there is no space
  34  * in what we get from the device). This is a known drawback and
  35  * firmwares >= 1.4 add header space that can be used to insert the
  36  * ethernet header without having to reallocate and copy.
  37  *
  38  * TX error handling is tricky; because we have to FIFO/queue the
  39  * buffers for transmission (as the hardware likes it aggregated), we
  40  * just give the skb to the TX subsystem and by the time it is
  41  * transmitted, we have long forgotten about it. So we just don't care
  42  * too much about it.
  43  *
  44  * Note that when the device is in idle mode with the basestation, we
  45  * need to negotiate coming back up online. That involves negotiation
  46  * and possible user space interaction. Thus, we defer to a workqueue
  47  * to do all that. By default, we only queue a single packet and drop
  48  * the rest, as potentially the time to go back from idle to normal is
  49  * long.
  50  *
  51  * ROADMAP
  52  *
  53  * i2400m_open         Called on ifconfig up
  54  * i2400m_stop         Called on ifconfig down
  55  *
  56  * i2400m_hard_start_xmit Called by the network stack to send a packet
  57  *   i2400m_net_wake_tx   Wake up device from basestation-IDLE & TX
  58  *     i2400m_wake_tx_work
  59  *       i2400m_cmd_exit_idle
  60  *       i2400m_tx
  61  *   i2400m_net_tx        TX a data frame
  62  *     i2400m_tx
  63  *
  64  * i2400m_change_mtu      Called on ifconfig mtu XXX
  65  *
  66  * i2400m_tx_timeout      Called when the device times out
  67  *
  68  * i2400m_net_rx          Called by the RX code when a data frame is
  69  *                        available (firmware <= 1.3)
  70  * i2400m_net_erx         Called by the RX code when a data frame is
  71  *                        available (firmware >= 1.4).
  72  * i2400m_netdev_setup    Called to setup all the netdev stuff from
  73  *                        alloc_netdev.
  74  */
  75 #include <linux/if_arp.h>
  76 #include <linux/netdevice.h>
  77 #include "i2400m.h"
  78
  79
  80 #define D_SUBMODULE netdev
  81 #include "debug-levels.h"
  82
  83 enum {
  84 /* netdev interface */
  85         /*
  86          * Out of NWG spec (R1_v1.2.2), 3.3.3 ASN Bearer Plane MTU Size
  87          *
  88          * The MTU is 1400 or less
  89          */
  90         I2400M_MAX_MTU = 1400,
  91         I2400M_TX_TIMEOUT = HZ,
  92         I2400M_TX_QLEN = 5,
  93 };
  94
  95
  96 static
  97 int i2400m_open(struct net_device *net_dev)
  98 {
  99         int result;
 100         struct i2400m *i2400m = net_dev_to_i2400m(net_dev);
 101         struct device *dev = i2400m_dev(i2400m);
 102
 103         d_fnstart(3, dev, "(net_dev %p [i2400m %p])\n", net_dev, i2400m);
 104         if (i2400m->ready == 0) {
 105                 dev_err(dev, "Device is still initializing\n");
 106                 result = -EBUSY;
 107         } else
 108                 result = 0;
 109         d_fnend(3, dev, "(net_dev %p [i2400m %p]) = %d\n",
 110                 net_dev, i2400m, result);
 111         return result;
 112 }
 113
 114
 115 /*
 116  *
 117  * On kernel versions where cancel_work_sync() didn't return anything,
 118  * we rely on wake_tx_skb() being non-NULL.
 119  */
 120 static
 121 int i2400m_stop(struct net_device *net_dev)
 122 {
 123         struct i2400m *i2400m = net_dev_to_i2400m(net_dev);
 124         struct device *dev = i2400m_dev(i2400m);
 125
 126         d_fnstart(3, dev, "(net_dev %p [i2400m %p])\n", net_dev, i2400m);
 127         /* See i2400m_hard_start_xmit(), references are taken there
 128          * and here we release them if the work was still
 129          * pending. Note we can't differentiate work not pending vs
 130          * never scheduled, so the NULL check does that. */
 131         if (cancel_work_sync(&i2400m->wake_tx_ws) == 0
 132             && i2400m->wake_tx_skb != NULL) {
 133                 unsigned long flags;
 134                 struct sk_buff *wake_tx_skb;
 135                 spin_lock_irqsave(&i2400m->tx_lock, flags);
 136                 wake_tx_skb = i2400m->wake_tx_skb;      /* compat help */
 137                 i2400m->wake_tx_skb = NULL;     /* compat help */
 138                 spin_unlock_irqrestore(&i2400m->tx_lock, flags);
 139                 i2400m_put(i2400m);
 140                 kfree_skb(wake_tx_skb);
 141         }
 142         d_fnend(3, dev, "(net_dev %p [i2400m %p]) = 0\n", net_dev, i2400m);
 143         return 0;
 144 }
 145
 146
 147 /*
 148  * Wake up the device and transmit a held SKB, then restart the net queue
 149  *
 150  * When the device goes into basestation-idle mode, we need to tell it
 151  * to exit that mode; it will negotiate with the base station, user
 152  * space may have to intervene to rehandshake crypto and then tell us
 153  * when it is ready to transmit the packet we have "queued". Still we
 154  * need to give it sometime after it reports being ok.
 155  *
 156  * On error, there is not much we can do. If the error was on TX, we
 157  * still wake the queue up to see if the next packet will be luckier.
 158  *
 159  * If _cmd_exit_idle() fails...well, it could be many things; most
 160  * commonly it is that something else took the device out of IDLE mode
 161  * (for example, the base station). In that case we get an -EILSEQ and
 162  * we are just going to ignore that one. If the device is back to
 163  * connected, then fine -- if it is someother state, the packet will
 164  * be dropped anyway.
 165  */
 166 void i2400m_wake_tx_work(struct work_struct *ws)
 167 {
 168         int result;
 169         struct i2400m *i2400m = container_of(ws, struct i2400m, wake_tx_ws);
 170         struct device *dev = i2400m_dev(i2400m);
 171         struct sk_buff *skb = i2400m->wake_tx_skb;
 172         unsigned long flags;
 173
 174         spin_lock_irqsave(&i2400m->tx_lock, flags);
 175         skb = i2400m->wake_tx_skb;
 176         i2400m->wake_tx_skb = NULL;
 177         spin_unlock_irqrestore(&i2400m->tx_lock, flags);
 178
 179         d_fnstart(3, dev, "(ws %p i2400m %p skb %p)\n", ws, i2400m, skb);
 180         result = -EINVAL;
 181         if (skb == NULL) {
 182                 dev_err(dev, "WAKE&TX: skb dissapeared!\n");
 183                 goto out_put;
 184         }
 185         result = i2400m_cmd_exit_idle(i2400m);
 186         if (result == -EILSEQ)
 187                 result = 0;
 188         if (result < 0) {
 189                 dev_err(dev, "WAKE&TX: device didn't get out of idle: "
 190                         "%d\n", result);
 191                         goto error;
 192         }
 193         result = wait_event_timeout(i2400m->state_wq,
 194                                     i2400m->state != I2400M_SS_IDLE, 5 * HZ);
 195         if (result == 0)
 196                 result = -ETIMEDOUT;
 197         if (result < 0) {
 198                 dev_err(dev, "WAKE&TX: error waiting for device to exit IDLE: "
 199                         "%d\n", result);
 200                 goto error;
 201         }
 202         msleep(20);     /* device still needs some time or it drops it */
 203         result = i2400m_tx(i2400m, skb->data, skb->len, I2400M_PT_DATA);
 204         netif_wake_queue(i2400m->wimax_dev.net_dev);
 205 error:
 206         kfree_skb(skb); /* refcount transferred by _hard_start_xmit() */
 207 out_put:
 208         i2400m_put(i2400m);
 209         d_fnend(3, dev, "(ws %p i2400m %p skb %p) = void [%d]\n",
 210                 ws, i2400m, skb, result);
 211 }
 212
 213
 214 /*
 215  * Prepare the data payload TX header
 216  *
 217  * The i2400m expects a 4 byte header in front of a data packet.
 218  *
 219  * Because we pretend to be an ethernet device, this packet comes with
 220  * an ethernet header. Pull it and push our header.
 221  */
 222 static
 223 void i2400m_tx_prep_header(struct sk_buff *skb)
 224 {
 225         struct i2400m_pl_data_hdr *pl_hdr;
 226         skb_pull(skb, ETH_HLEN);
 227         pl_hdr = (struct i2400m_pl_data_hdr *) skb_push(skb, sizeof(*pl_hdr));
 228         pl_hdr->reserved = 0;
 229 }
 230
 231
 232 /*
 233  * TX an skb to an idle device
 234  *
 235  * When the device is in basestation-idle mode, we need to wake it up
 236  * and then TX. So we queue a work_struct for doing so.
 237  *
 238  * We need to get an extra ref for the skb (so it is not dropped), as
 239  * well as be careful not to queue more than one request (won't help
 240  * at all). If more than one request comes or there are errors, we
 241  * just drop the packets (see i2400m_hard_start_xmit()).
 242  */
 243 static
 244 int i2400m_net_wake_tx(struct i2400m *i2400m, struct net_device *net_dev,
 245                        struct sk_buff *skb)
 246 {
 247         int result;
 248         struct device *dev = i2400m_dev(i2400m);
 249         unsigned long flags;
 250
 251         d_fnstart(3, dev, "(skb %p net_dev %p)\n", skb, net_dev);
 252         if (net_ratelimit()) {
 253                 d_printf(3, dev, "WAKE&NETTX: "
 254                          "skb %p sending %d bytes to radio\n",
 255                          skb, skb->len);
 256                 d_dump(4, dev, skb->data, skb->len);
 257         }
 258         /* We hold a ref count for i2400m and skb, so when
 259          * stopping() the device, we need to cancel that work
 260          * and if pending, release those resources. */
 261         result = 0;
 262         spin_lock_irqsave(&i2400m->tx_lock, flags);
 263         if (!work_pending(&i2400m->wake_tx_ws)) {
 264                 netif_stop_queue(net_dev);
 265                 i2400m_get(i2400m);
 266                 i2400m->wake_tx_skb = skb_get(skb);     /* transfer ref count */
 267                 i2400m_tx_prep_header(skb);
 268                 result = schedule_work(&i2400m->wake_tx_ws);
 269                 WARN_ON(result == 0);
 270         }
 271         spin_unlock_irqrestore(&i2400m->tx_lock, flags);
 272         if (result == 0) {
 273                 /* Yes, this happens even if we stopped the
 274                  * queue -- blame the queue disciplines that
 275                  * queue without looking -- I guess there is a reason
 276                  * for that. */
 277                 if (net_ratelimit())
 278                         d_printf(1, dev, "NETTX: device exiting idle, "
 279                                  "dropping skb %p, queue running %d\n",
 280                                  skb, netif_queue_stopped(net_dev));
 281                 result = -EBUSY;
 282         }
 283         d_fnend(3, dev, "(skb %p net_dev %p) = %d\n", skb, net_dev, result);
 284         return result;
 285 }
 286
 287
 288 /*
 289  * Transmit a packet to the base station on behalf of the network stack.
 290  *
 291  * Returns: 0 if ok, < 0 errno code on error.
 292  *
 293  * We need to pull the ethernet header and add the hardware header,
 294  * which is currently set to all zeroes and reserved.
 295  */
 296 static
 297 int i2400m_net_tx(struct i2400m *i2400m, struct net_device *net_dev,
 298                   struct sk_buff *skb)
 299 {
 300         int result;
 301         struct device *dev = i2400m_dev(i2400m);
 302
 303         d_fnstart(3, dev, "(i2400m %p net_dev %p skb %p)\n",
 304                   i2400m, net_dev, skb);
 305         /* FIXME: check eth hdr, only IPv4 is routed by the device as of now */
 306         net_dev->trans_start = jiffies;
 307         i2400m_tx_prep_header(skb);
 308         d_printf(3, dev, "NETTX: skb %p sending %d bytes to radio\n",
 309                  skb, skb->len);
 310         d_dump(4, dev, skb->data, skb->len);
 311         result = i2400m_tx(i2400m, skb->data, skb->len, I2400M_PT_DATA);
 312         d_fnend(3, dev, "(i2400m %p net_dev %p skb %p) = %d\n",
 313                 i2400m, net_dev, skb, result);
 314         return result;
 315 }
 316
 317
 318 /*
 319  * Transmit a packet to the base station on behalf of the network stack
 320  *
 321  *
 322  * Returns: NETDEV_TX_OK (always, even in case of error)
 323  *
 324  * In case of error, we just drop it. Reasons:
 325  *
 326  *  - we add a hw header to each skb, and if the network stack
 327  *    retries, we have no way to know if that skb has it or not.
 328  *
 329  *  - network protocols have their own drop-recovery mechanisms
 330  *
 331  *  - there is not much else we can do
 332  *
 333  * If the device is idle, we need to wake it up; that is an operation
 334  * that will sleep. See i2400m_net_wake_tx() for details.
 335  */
 336 static
 337 netdev_tx_t i2400m_hard_start_xmit(struct sk_buff *skb,
 338                                          struct net_device *net_dev)
 339 {
 340         struct i2400m *i2400m = net_dev_to_i2400m(net_dev);
 341         struct device *dev = i2400m_dev(i2400m);
 342         int result;
 343
 344         d_fnstart(3, dev, "(skb %p net_dev %p)\n", skb, net_dev);
 345         if (i2400m->state == I2400M_SS_IDLE)
 346                 result = i2400m_net_wake_tx(i2400m, net_dev, skb);
 347         else
 348                 result = i2400m_net_tx(i2400m, net_dev, skb);
 349         if (result <  0)
 350                 net_dev->stats.tx_dropped++;
 351         else {
 352                 net_dev->stats.tx_packets++;
 353                 net_dev->stats.tx_bytes += skb->len;
 354         }
 355         kfree_skb(skb);
 356
 357         d_fnend(3, dev, "(skb %p net_dev %p)\n", skb, net_dev);
 358         return NETDEV_TX_OK;
 359 }
 360
 361
 362 static
 363 int i2400m_change_mtu(struct net_device *net_dev, int new_mtu)
 364 {
 365         int result;
 366         struct i2400m *i2400m = net_dev_to_i2400m(net_dev);
 367         struct device *dev = i2400m_dev(i2400m);
 368
 369         if (new_mtu >= I2400M_MAX_MTU) {
 370                 dev_err(dev, "Cannot change MTU to %d (max is %d)\n",
 371                         new_mtu, I2400M_MAX_MTU);
 372                 result = -EINVAL;
 373         } else {
 374                 net_dev->mtu = new_mtu;
 375                 result = 0;
 376         }
 377         return result;
 378 }
 379
 380
 381 static
 382 void i2400m_tx_timeout(struct net_device *net_dev)
 383 {
 384         /*
 385          * We might want to kick the device
 386          *
 387          * There is not much we can do though, as the device requires
 388          * that we send the data aggregated. By the time we receive
 389          * this, there might be data pending to be sent or not...
 390          */
 391         net_dev->stats.tx_errors++;
 392         return;
 393 }
 394
 395
 396 /*
 397  * Create a fake ethernet header
 398  *
 399  * For emulating an ethernet device, every received IP header has to
 400  * be prefixed with an ethernet header. Fake it with the given
 401  * protocol.
 402  */
 403 static
 404 void i2400m_rx_fake_eth_header(struct net_device *net_dev,
 405                                void *_eth_hdr, __be16 protocol)
 406 {
 407         struct i2400m *i2400m = net_dev_to_i2400m(net_dev);
 408         struct ethhdr *eth_hdr = _eth_hdr;
 409
 410         memcpy(eth_hdr->h_dest, net_dev->dev_addr, sizeof(eth_hdr->h_dest));
 411         memcpy(eth_hdr->h_source, i2400m->src_mac_addr,
 412                sizeof(eth_hdr->h_source));
 413         eth_hdr->h_proto = protocol;
 414 }
 415
 416
 417 /*
 418  * i2400m_net_rx - pass a network packet to the stack
 419  *
 420  * @i2400m: device instance
 421  * @skb_rx: the skb where the buffer pointed to by @buf is
 422  * @i: 1 if payload is the only one
 423  * @buf: pointer to the buffer containing the data
 424  * @len: buffer's length
 425  *
 426  * This is only used now for the v1.3 firmware. It will be deprecated
 427  * in >= 2.6.31.
 428  *
 429  * Note that due to firmware limitations, we don't have space to add
 430  * an ethernet header, so we need to copy each packet. Firmware
 431  * versions >= v1.4 fix this [see i2400m_net_erx()].
 432  *
 433  * We just clone the skb and set it up so that it's skb->data pointer
 434  * points to "buf" and it's length.
 435  *
 436  * Note that if the payload is the last (or the only one) in a
 437  * multi-payload message, we don't clone the SKB but just reuse it.
 438  *
 439  * This function is normally run from a thread context. However, we
 440  * still use netif_rx() instead of netif_receive_skb() as was
 441  * recommended in the mailing list. Reason is in some stress tests
 442  * when sending/receiving a lot of data we seem to hit a softlock in
 443  * the kernel's TCP implementation [aroudn tcp_delay_timer()]. Using
 444  * netif_rx() took care of the issue.
 445  *
 446  * This is, of course, still open to do more research on why running
 447  * with netif_receive_skb() hits this softlock. FIXME.
 448  *
 449  * FIXME: currently we don't do any efforts at distinguishing if what
 450  * we got was an IPv4 or IPv6 header, to setup the protocol field
 451  * correctly.
 452  */
 453 void i2400m_net_rx(struct i2400m *i2400m, struct sk_buff *skb_rx,
 454                    unsigned i, const void *buf, int buf_len)
 455 {
 456         struct net_device *net_dev = i2400m->wimax_dev.net_dev;
 457         struct device *dev = i2400m_dev(i2400m);
 458         struct sk_buff *skb;
 459
 460         d_fnstart(2, dev, "(i2400m %p buf %p buf_len %d)\n",
 461                   i2400m, buf, buf_len);
 462         if (i) {
 463                 skb = skb_get(skb_rx);
 464                 d_printf(2, dev, "RX: reusing first payload skb %p\n", skb);
 465                 skb_pull(skb, buf - (void *) skb->data);
 466                 skb_trim(skb, (void *) skb_end_pointer(skb) - buf);
 467         } else {
 468                 /* Yes, this is bad -- a lot of overhead -- see
 469                  * comments at the top of the file */
 470                 skb = __netdev_alloc_skb(net_dev, buf_len, GFP_KERNEL);
 471                 if (skb == NULL) {
 472                         dev_err(dev, "NETRX: no memory to realloc skb\n");
 473                         net_dev->stats.rx_dropped++;
 474                         goto error_skb_realloc;
 475                 }
 476                 memcpy(skb_put(skb, buf_len), buf, buf_len);
 477         }
 478         i2400m_rx_fake_eth_header(i2400m->wimax_dev.net_dev,
 479                                   skb->data - ETH_HLEN,
 480                                   cpu_to_be16(ETH_P_IP));
 481         skb_set_mac_header(skb, -ETH_HLEN);
 482         skb->dev = i2400m->wimax_dev.net_dev;
 483         skb->protocol = htons(ETH_P_IP);
 484         net_dev->stats.rx_packets++;
 485         net_dev->stats.rx_bytes += buf_len;
 486         d_printf(3, dev, "NETRX: receiving %d bytes to network stack\n",
 487                 buf_len);
 488         d_dump(4, dev, buf, buf_len);
 489         netif_rx_ni(skb);       /* see notes in function header */
 490 error_skb_realloc:
 491         d_fnend(2, dev, "(i2400m %p buf %p buf_len %d) = void\n",
 492                 i2400m, buf, buf_len);
 493 }
 494
 495
 496 /*
 497  * i2400m_net_erx - pass a network packet to the stack (extended version)
 498  *
 499  * @i2400m: device descriptor
 500  * @skb: the skb where the packet is - the skb should be set to point
 501  *     at the IP packet; this function will add ethernet headers if
 502  *     needed.
 503  * @cs: packet type
 504  *
 505  * This is only used now for firmware >= v1.4. Note it is quite
 506  * similar to i2400m_net_rx() (used only for v1.3 firmware).
 507  *
 508  * This function is normally run from a thread context. However, we
 509  * still use netif_rx() instead of netif_receive_skb() as was
 510  * recommended in the mailing list. Reason is in some stress tests
 511  * when sending/receiving a lot of data we seem to hit a softlock in
 512  * the kernel's TCP implementation [aroudn tcp_delay_timer()]. Using
 513  * netif_rx() took care of the issue.
 514  *
 515  * This is, of course, still open to do more research on why running
 516  * with netif_receive_skb() hits this softlock. FIXME.
 517  */
 518 void i2400m_net_erx(struct i2400m *i2400m, struct sk_buff *skb,
 519                     enum i2400m_cs cs)
 520 {
 521         struct net_device *net_dev = i2400m->wimax_dev.net_dev;
 522         struct device *dev = i2400m_dev(i2400m);
 523         int protocol;
 524
 525         d_fnstart(2, dev, "(i2400m %p skb %p [%u] cs %d)\n",
 526                   i2400m, skb, skb->len, cs);
 527         switch(cs) {
 528         case I2400M_CS_IPV4_0:
 529         case I2400M_CS_IPV4:
 530                 protocol = ETH_P_IP;
 531                 i2400m_rx_fake_eth_header(i2400m->wimax_dev.net_dev,
 532                                           skb->data - ETH_HLEN,
 533                                           cpu_to_be16(ETH_P_IP));
 534                 skb_set_mac_header(skb, -ETH_HLEN);
 535                 skb->dev = i2400m->wimax_dev.net_dev;
 536                 skb->protocol = htons(ETH_P_IP);
 537                 net_dev->stats.rx_packets++;
 538                 net_dev->stats.rx_bytes += skb->len;
 539                 break;
 540         default:
 541                 dev_err(dev, "ERX: BUG? CS type %u unsupported\n", cs);
 542                 goto error;
 543
 544         }
 545         d_printf(3, dev, "ERX: receiving %d bytes to the network stack\n",
 546                  skb->len);
 547         d_dump(4, dev, skb->data, skb->len);
 548         netif_rx_ni(skb);       /* see notes in function header */
 549 error:
 550         d_fnend(2, dev, "(i2400m %p skb %p [%u] cs %d) = void\n",
 551                 i2400m, skb, skb->len, cs);
 552 }
 553
 554 static const struct net_device_ops i2400m_netdev_ops = {
 555         .ndo_open = i2400m_open,
 556         .ndo_stop = i2400m_stop,
 557         .ndo_start_xmit = i2400m_hard_start_xmit,
 558         .ndo_tx_timeout = i2400m_tx_timeout,
 559         .ndo_change_mtu = i2400m_change_mtu,
 560 };
 561
 562
 563 /**
 564  * i2400m_netdev_setup - Setup setup @net_dev's i2400m private data
 565  *
 566  * Called by alloc_netdev()
 567  */
 568 void i2400m_netdev_setup(struct net_device *net_dev)
 569 {
 570         d_fnstart(3, NULL, "(net_dev %p)\n", net_dev);
 571         ether_setup(net_dev);
 572         net_dev->mtu = I2400M_MAX_MTU;
 573         net_dev->tx_queue_len = I2400M_TX_QLEN;
 574         net_dev->features =
 575                   NETIF_F_VLAN_CHALLENGED
 576                 | NETIF_F_HIGHDMA;
 577         net_dev->flags =
 578                 IFF_NOARP               /* i2400m is apure IP device */
 579                 & (~IFF_BROADCAST       /* i2400m is P2P */
 580                    & ~IFF_MULTICAST);
 581         net_dev->watchdog_timeo = I2400M_TX_TIMEOUT;
 582         net_dev->netdev_ops = &i2400m_netdev_ops;
 583         d_fnend(3, NULL, "(net_dev %p) = void\n", net_dev);
 584 }
 585 EXPORT_SYMBOL_GPL(i2400m_netdev_setup);
 586