root/drivers/misc/sgi-xp/xpnet.c

DEFINITIONS

1. xpnet_receive
2. xpnet_connection_activity
3. xpnet_dev_open
4. xpnet_dev_stop
5. xpnet_send_completed
6. xpnet_send
7. xpnet_dev_hard_start_xmit
8. xpnet_dev_tx_timeout
9. xpnet_init
10. xpnet_exit

   1 /*
   2  * This file is subject to the terms and conditions of the GNU General Public
   3  * License.  See the file "COPYING" in the main directory of this archive
   4  * for more details.
   5  *
   6  * Copyright (C) 1999-2009 Silicon Graphics, Inc. All rights reserved.
   7  */
   8 
   9 /*
  10  * Cross Partition Network Interface (XPNET) support
  11  *
  12  *      XPNET provides a virtual network layered on top of the Cross
  13  *      Partition communication layer.
  14  *
  15  *      XPNET provides direct point-to-point and broadcast-like support
  16  *      for an ethernet-like device.  The ethernet broadcast medium is
  17  *      replaced with a point-to-point message structure which passes
  18  *      pointers to a DMA-capable block that a remote partition should
  19  *      retrieve and pass to the upper level networking layer.
  20  *
  21  */
  22 
  23 #include <linux/slab.h>
  24 #include <linux/module.h>
  25 #include <linux/netdevice.h>
  26 #include <linux/etherdevice.h>
  27 #include "xp.h"
  28 
  29 /*
  30  * The message payload transferred by XPC.
  31  *
  32  * buf_pa is the physical address where the DMA should pull from.
  33  *
  34  * NOTE: for performance reasons, buf_pa should _ALWAYS_ begin on a
  35  * cacheline boundary.  To accomplish this, we record the number of
  36  * bytes from the beginning of the first cacheline to the first useful
  37  * byte of the skb (leadin_ignore) and the number of bytes from the
  38  * last useful byte of the skb to the end of the last cacheline
  39  * (tailout_ignore).
  40  *
  41  * size is the number of bytes to transfer which includes the skb->len
  42  * (useful bytes of the senders skb) plus the leadin and tailout
  43  */
  44 struct xpnet_message {
  45         u16 version;            /* Version for this message */
  46         u16 embedded_bytes;     /* #of bytes embedded in XPC message */
  47         u32 magic;              /* Special number indicating this is xpnet */
  48         unsigned long buf_pa;   /* phys address of buffer to retrieve */
  49         u32 size;               /* #of bytes in buffer */
  50         u8 leadin_ignore;       /* #of bytes to ignore at the beginning */
  51         u8 tailout_ignore;      /* #of bytes to ignore at the end */
  52         unsigned char data;     /* body of small packets */
  53 };
  54 
  55 /*
  56  * Determine the size of our message, the cacheline aligned size,
  57  * and then the number of message will request from XPC.
  58  *
  59  * XPC expects each message to exist in an individual cacheline.
  60  */
  61 #define XPNET_MSG_SIZE          XPC_MSG_PAYLOAD_MAX_SIZE
  62 #define XPNET_MSG_DATA_MAX      \
  63                 (XPNET_MSG_SIZE - offsetof(struct xpnet_message, data))
  64 #define XPNET_MSG_NENTRIES      (PAGE_SIZE / XPC_MSG_MAX_SIZE)
  65 
  66 #define XPNET_MAX_KTHREADS      (XPNET_MSG_NENTRIES + 1)
  67 #define XPNET_MAX_IDLE_KTHREADS (XPNET_MSG_NENTRIES + 1)
  68 
  69 /*
  70  * Version number of XPNET implementation. XPNET can always talk to versions
  71  * with same major #, and never talk to versions with a different version.
  72  */
  73 #define _XPNET_VERSION(_major, _minor)  (((_major) << 4) | (_minor))
  74 #define XPNET_VERSION_MAJOR(_v)         ((_v) >> 4)
  75 #define XPNET_VERSION_MINOR(_v)         ((_v) & 0xf)
  76 
  77 #define XPNET_VERSION _XPNET_VERSION(1, 0)      /* version 1.0 */
  78 #define XPNET_VERSION_EMBED _XPNET_VERSION(1, 1)        /* version 1.1 */
  79 #define XPNET_MAGIC     0x88786984      /* "XNET" */
  80 
  81 #define XPNET_VALID_MSG(_m)                                                  \
  82    ((XPNET_VERSION_MAJOR(_m->version) == XPNET_VERSION_MAJOR(XPNET_VERSION)) \
  83     && (msg->magic == XPNET_MAGIC))
  84 
  85 #define XPNET_DEVICE_NAME               "xp0"
  86 
  87 /*
  88  * When messages are queued with xpc_send_notify, a kmalloc'd buffer
  89  * of the following type is passed as a notification cookie.  When the
  90  * notification function is called, we use the cookie to decide
  91  * whether all outstanding message sends have completed.  The skb can
  92  * then be released.
  93  */
  94 struct xpnet_pending_msg {
  95         struct sk_buff *skb;
  96         atomic_t use_count;
  97 };
  98 
  99 struct net_device *xpnet_device;
 100 
 101 /*
 102  * When we are notified of other partitions activating, we add them to
 103  * our bitmask of partitions to which we broadcast.
 104  */
 105 static unsigned long *xpnet_broadcast_partitions;
 106 /* protect above */
 107 static DEFINE_SPINLOCK(xpnet_broadcast_lock);
 108 
 109 /*
 110  * Since the Block Transfer Engine (BTE) is being used for the transfer
 111  * and it relies upon cache-line size transfers, we need to reserve at
 112  * least one cache-line for head and tail alignment.  The BTE is
 113  * limited to 8MB transfers.
 114  *
 115  * Testing has shown that changing MTU to greater than 64KB has no effect
 116  * on TCP as the two sides negotiate a Max Segment Size that is limited
 117  * to 64K.  Other protocols May use packets greater than this, but for
 118  * now, the default is 64KB.
 119  */
 120 #define XPNET_MAX_MTU (0x800000UL - L1_CACHE_BYTES)
 121 /* 68 comes from min TCP+IP+MAC header */
 122 #define XPNET_MIN_MTU 68
 123 /* 32KB has been determined to be the ideal */
 124 #define XPNET_DEF_MTU (0x8000UL)
 125 
 126 /*
 127  * The partid is encapsulated in the MAC address beginning in the following
 128  * octet and it consists of two octets.
 129  */
 130 #define XPNET_PARTID_OCTET      2
 131 
 132 /* Define the XPNET debug device structures to be used with dev_dbg() et al */
 133 
 134 struct device_driver xpnet_dbg_name = {
 135         .name = "xpnet"
 136 };
 137 
 138 struct device xpnet_dbg_subname = {
 139         .init_name = "",        /* set to "" */
 140         .driver = &xpnet_dbg_name
 141 };
 142 
 143 struct device *xpnet = &xpnet_dbg_subname;
 144 
 145 /*
 146  * Packet was recevied by XPC and forwarded to us.
 147  */
 148 static void
 149 xpnet_receive(short partid, int channel, struct xpnet_message *msg)
 150 {
 151         struct sk_buff *skb;
 152         void *dst;
 153         enum xp_retval ret;
 154 
 155         if (!XPNET_VALID_MSG(msg)) {
 156                 /*
 157                  * Packet with a different XPC version.  Ignore.
 158                  */
 159                 xpc_received(partid, channel, (void *)msg);
 160 
 161                 xpnet_device->stats.rx_errors++;
 162 
 163                 return;
 164         }
 165         dev_dbg(xpnet, "received 0x%lx, %d, %d, %d\n", msg->buf_pa, msg->size,
 166                 msg->leadin_ignore, msg->tailout_ignore);
 167 
 168         /* reserve an extra cache line */
 169         skb = dev_alloc_skb(msg->size + L1_CACHE_BYTES);
 170         if (!skb) {
 171                 dev_err(xpnet, "failed on dev_alloc_skb(%d)\n",
 172                         msg->size + L1_CACHE_BYTES);
 173 
 174                 xpc_received(partid, channel, (void *)msg);
 175 
 176                 xpnet_device->stats.rx_errors++;
 177 
 178                 return;
 179         }
 180 
 181         /*
 182          * The allocated skb has some reserved space.
 183          * In order to use xp_remote_memcpy(), we need to get the
 184          * skb->data pointer moved forward.
 185          */
 186         skb_reserve(skb, (L1_CACHE_BYTES - ((u64)skb->data &
 187                                             (L1_CACHE_BYTES - 1)) +
 188                           msg->leadin_ignore));
 189 
 190         /*
 191          * Update the tail pointer to indicate data actually
 192          * transferred.
 193          */
 194         skb_put(skb, (msg->size - msg->leadin_ignore - msg->tailout_ignore));
 195 
 196         /*
 197          * Move the data over from the other side.
 198          */
 199         if ((XPNET_VERSION_MINOR(msg->version) == 1) &&
 200             (msg->embedded_bytes != 0)) {
 201                 dev_dbg(xpnet, "copying embedded message. memcpy(0x%p, 0x%p, "
 202                         "%lu)\n", skb->data, &msg->data,
 203                         (size_t)msg->embedded_bytes);
 204 
 205                 skb_copy_to_linear_data(skb, &msg->data,
 206                                         (size_t)msg->embedded_bytes);
 207         } else {
 208                 dst = (void *)((u64)skb->data & ~(L1_CACHE_BYTES - 1));
 209                 dev_dbg(xpnet, "transferring buffer to the skb->data area;\n\t"
 210                         "xp_remote_memcpy(0x%p, 0x%p, %hu)\n", dst,
 211                                           (void *)msg->buf_pa, msg->size);
 212 
 213                 ret = xp_remote_memcpy(xp_pa(dst), msg->buf_pa, msg->size);
 214                 if (ret != xpSuccess) {
 215                         /*
 216                          * !!! Need better way of cleaning skb.  Currently skb
 217                          * !!! appears in_use and we can't just call
 218                          * !!! dev_kfree_skb.
 219                          */
 220                         dev_err(xpnet, "xp_remote_memcpy(0x%p, 0x%p, 0x%hx) "
 221                                 "returned error=0x%x\n", dst,
 222                                 (void *)msg->buf_pa, msg->size, ret);
 223 
 224                         xpc_received(partid, channel, (void *)msg);
 225 
 226                         xpnet_device->stats.rx_errors++;
 227 
 228                         return;
 229                 }
 230         }
 231 
 232         dev_dbg(xpnet, "<skb->head=0x%p skb->data=0x%p skb->tail=0x%p "
 233                 "skb->end=0x%p skb->len=%d\n", (void *)skb->head,
 234                 (void *)skb->data, skb_tail_pointer(skb), skb_end_pointer(skb),
 235                 skb->len);
 236 
 237         skb->protocol = eth_type_trans(skb, xpnet_device);
 238         skb->ip_summed = CHECKSUM_UNNECESSARY;
 239 
 240         dev_dbg(xpnet, "passing skb to network layer\n"
 241                 "\tskb->head=0x%p skb->data=0x%p skb->tail=0x%p "
 242                 "skb->end=0x%p skb->len=%d\n",
 243                 (void *)skb->head, (void *)skb->data, skb_tail_pointer(skb),
 244                 skb_end_pointer(skb), skb->len);
 245 
 246         xpnet_device->stats.rx_packets++;
 247         xpnet_device->stats.rx_bytes += skb->len + ETH_HLEN;
 248 
 249         netif_rx_ni(skb);
 250         xpc_received(partid, channel, (void *)msg);
 251 }
 252 
 253 /*
 254  * This is the handler which XPC calls during any sort of change in
 255  * state or message reception on a connection.
 256  */
 257 static void
 258 xpnet_connection_activity(enum xp_retval reason, short partid, int channel,
 259                           void *data, void *key)
 260 {
 261         DBUG_ON(partid < 0 || partid >= xp_max_npartitions);
 262         DBUG_ON(channel != XPC_NET_CHANNEL);
 263 
 264         switch (reason) {
 265         case xpMsgReceived:     /* message received */
 266                 DBUG_ON(data == NULL);
 267 
 268                 xpnet_receive(partid, channel, (struct xpnet_message *)data);
 269                 break;
 270 
 271         case xpConnected:       /* connection completed to a partition */
 272                 spin_lock_bh(&xpnet_broadcast_lock);
 273                 __set_bit(partid, xpnet_broadcast_partitions);
 274                 spin_unlock_bh(&xpnet_broadcast_lock);
 275 
 276                 netif_carrier_on(xpnet_device);
 277 
 278                 dev_dbg(xpnet, "%s connected to partition %d\n",
 279                         xpnet_device->name, partid);
 280                 break;
 281 
 282         default:
 283                 spin_lock_bh(&xpnet_broadcast_lock);
 284                 __clear_bit(partid, xpnet_broadcast_partitions);
 285                 spin_unlock_bh(&xpnet_broadcast_lock);
 286 
 287                 if (bitmap_empty((unsigned long *)xpnet_broadcast_partitions,
 288                                  xp_max_npartitions)) {
 289                         netif_carrier_off(xpnet_device);
 290                 }
 291 
 292                 dev_dbg(xpnet, "%s disconnected from partition %d\n",
 293                         xpnet_device->name, partid);
 294                 break;
 295         }
 296 }
 297 
 298 static int
 299 xpnet_dev_open(struct net_device *dev)
 300 {
 301         enum xp_retval ret;
 302 
 303         dev_dbg(xpnet, "calling xpc_connect(%d, 0x%p, NULL, %ld, %ld, %ld, "
 304                 "%ld)\n", XPC_NET_CHANNEL, xpnet_connection_activity,
 305                 (unsigned long)XPNET_MSG_SIZE,
 306                 (unsigned long)XPNET_MSG_NENTRIES,
 307                 (unsigned long)XPNET_MAX_KTHREADS,
 308                 (unsigned long)XPNET_MAX_IDLE_KTHREADS);
 309 
 310         ret = xpc_connect(XPC_NET_CHANNEL, xpnet_connection_activity, NULL,
 311                           XPNET_MSG_SIZE, XPNET_MSG_NENTRIES,
 312                           XPNET_MAX_KTHREADS, XPNET_MAX_IDLE_KTHREADS);
 313         if (ret != xpSuccess) {
 314                 dev_err(xpnet, "ifconfig up of %s failed on XPC connect, "
 315                         "ret=%d\n", dev->name, ret);
 316 
 317                 return -ENOMEM;
 318         }
 319 
 320         dev_dbg(xpnet, "ifconfig up of %s; XPC connected\n", dev->name);
 321 
 322         return 0;
 323 }
 324 
 325 static int
 326 xpnet_dev_stop(struct net_device *dev)
 327 {
 328         xpc_disconnect(XPC_NET_CHANNEL);
 329 
 330         dev_dbg(xpnet, "ifconfig down of %s; XPC disconnected\n", dev->name);
 331 
 332         return 0;
 333 }
 334 
 335 /*
 336  * Notification that the other end has received the message and
 337  * DMA'd the skb information.  At this point, they are done with
 338  * our side.  When all recipients are done processing, we
 339  * release the skb and then release our pending message structure.
 340  */
 341 static void
 342 xpnet_send_completed(enum xp_retval reason, short partid, int channel,
 343                      void *__qm)
 344 {
 345         struct xpnet_pending_msg *queued_msg = (struct xpnet_pending_msg *)__qm;
 346 
 347         DBUG_ON(queued_msg == NULL);
 348 
 349         dev_dbg(xpnet, "message to %d notified with reason %d\n",
 350                 partid, reason);
 351 
 352         if (atomic_dec_return(&queued_msg->use_count) == 0) {
 353                 dev_dbg(xpnet, "all acks for skb->head=-x%p\n",
 354                         (void *)queued_msg->skb->head);
 355 
 356                 dev_kfree_skb_any(queued_msg->skb);
 357                 kfree(queued_msg);
 358         }
 359 }
 360 
 361 static void
 362 xpnet_send(struct sk_buff *skb, struct xpnet_pending_msg *queued_msg,
 363            u64 start_addr, u64 end_addr, u16 embedded_bytes, int dest_partid)
 364 {
 365         u8 msg_buffer[XPNET_MSG_SIZE];
 366         struct xpnet_message *msg = (struct xpnet_message *)&msg_buffer;
 367         u16 msg_size = sizeof(struct xpnet_message);
 368         enum xp_retval ret;
 369 
 370         msg->embedded_bytes = embedded_bytes;
 371         if (unlikely(embedded_bytes != 0)) {
 372                 msg->version = XPNET_VERSION_EMBED;
 373                 dev_dbg(xpnet, "calling memcpy(0x%p, 0x%p, 0x%lx)\n",
 374                         &msg->data, skb->data, (size_t)embedded_bytes);
 375                 skb_copy_from_linear_data(skb, &msg->data,
 376                                           (size_t)embedded_bytes);
 377                 msg_size += embedded_bytes - 1;
 378         } else {
 379                 msg->version = XPNET_VERSION;
 380         }
 381         msg->magic = XPNET_MAGIC;
 382         msg->size = end_addr - start_addr;
 383         msg->leadin_ignore = (u64)skb->data - start_addr;
 384         msg->tailout_ignore = end_addr - (u64)skb_tail_pointer(skb);
 385         msg->buf_pa = xp_pa((void *)start_addr);
 386 
 387         dev_dbg(xpnet, "sending XPC message to %d:%d\n"
 388                 "msg->buf_pa=0x%lx, msg->size=%u, "
 389                 "msg->leadin_ignore=%u, msg->tailout_ignore=%u\n",
 390                 dest_partid, XPC_NET_CHANNEL, msg->buf_pa, msg->size,
 391                 msg->leadin_ignore, msg->tailout_ignore);
 392 
 393         atomic_inc(&queued_msg->use_count);
 394 
 395         ret = xpc_send_notify(dest_partid, XPC_NET_CHANNEL, XPC_NOWAIT, msg,
 396                               msg_size, xpnet_send_completed, queued_msg);
 397         if (unlikely(ret != xpSuccess))
 398                 atomic_dec(&queued_msg->use_count);
 399 }
 400 
 401 /*
 402  * Network layer has formatted a packet (skb) and is ready to place it
 403  * "on the wire".  Prepare and send an xpnet_message to all partitions
 404  * which have connected with us and are targets of this packet.
 405  *
 406  * MAC-NOTE:  For the XPNET driver, the MAC address contains the
 407  * destination partid.  If the destination partid octets are 0xffff,
 408  * this packet is to be broadcast to all connected partitions.
 409  */
 410 static netdev_tx_t
 411 xpnet_dev_hard_start_xmit(struct sk_buff *skb, struct net_device *dev)
 412 {
 413         struct xpnet_pending_msg *queued_msg;
 414         u64 start_addr, end_addr;
 415         short dest_partid;
 416         u16 embedded_bytes = 0;
 417 
 418         dev_dbg(xpnet, ">skb->head=0x%p skb->data=0x%p skb->tail=0x%p "
 419                 "skb->end=0x%p skb->len=%d\n", (void *)skb->head,
 420                 (void *)skb->data, skb_tail_pointer(skb), skb_end_pointer(skb),
 421                 skb->len);
 422 
 423         if (skb->data[0] == 0x33) {
 424                 dev_kfree_skb(skb);
 425                 return NETDEV_TX_OK;    /* nothing needed to be done */
 426         }
 427 
 428         /*
 429          * The xpnet_pending_msg tracks how many outstanding
 430          * xpc_send_notifies are relying on this skb.  When none
 431          * remain, release the skb.
 432          */
 433         queued_msg = kmalloc(sizeof(struct xpnet_pending_msg), GFP_ATOMIC);
 434         if (queued_msg == NULL) {
 435                 dev_warn(xpnet, "failed to kmalloc %ld bytes; dropping "
 436                          "packet\n", sizeof(struct xpnet_pending_msg));
 437 
 438                 dev->stats.tx_errors++;
 439                 dev_kfree_skb(skb);
 440                 return NETDEV_TX_OK;
 441         }
 442 
 443         /* get the beginning of the first cacheline and end of last */
 444         start_addr = ((u64)skb->data & ~(L1_CACHE_BYTES - 1));
 445         end_addr = L1_CACHE_ALIGN((u64)skb_tail_pointer(skb));
 446 
 447         /* calculate how many bytes to embed in the XPC message */
 448         if (unlikely(skb->len <= XPNET_MSG_DATA_MAX)) {
 449                 /* skb->data does fit so embed */
 450                 embedded_bytes = skb->len;
 451         }
 452 
 453         /*
 454          * Since the send occurs asynchronously, we set the count to one
 455          * and begin sending.  Any sends that happen to complete before
 456          * we are done sending will not free the skb.  We will be left
 457          * with that task during exit.  This also handles the case of
 458          * a packet destined for a partition which is no longer up.
 459          */
 460         atomic_set(&queued_msg->use_count, 1);
 461         queued_msg->skb = skb;
 462 
 463         if (skb->data[0] == 0xff) {
 464                 /* we are being asked to broadcast to all partitions */
 465                 for_each_set_bit(dest_partid, xpnet_broadcast_partitions,
 466                              xp_max_npartitions) {
 467 
 468                         xpnet_send(skb, queued_msg, start_addr, end_addr,
 469                                    embedded_bytes, dest_partid);
 470                 }
 471         } else {
 472                 dest_partid = (short)skb->data[XPNET_PARTID_OCTET + 1];
 473                 dest_partid |= (short)skb->data[XPNET_PARTID_OCTET + 0] << 8;
 474 
 475                 if (dest_partid >= 0 &&
 476                     dest_partid < xp_max_npartitions &&
 477                     test_bit(dest_partid, xpnet_broadcast_partitions) != 0) {
 478 
 479                         xpnet_send(skb, queued_msg, start_addr, end_addr,
 480                                    embedded_bytes, dest_partid);
 481                 }
 482         }
 483 
 484         dev->stats.tx_packets++;
 485         dev->stats.tx_bytes += skb->len;
 486 
 487         if (atomic_dec_return(&queued_msg->use_count) == 0) {
 488                 dev_kfree_skb(skb);
 489                 kfree(queued_msg);
 490         }
 491 
 492         return NETDEV_TX_OK;
 493 }
 494 
 495 /*
 496  * Deal with transmit timeouts coming from the network layer.
 497  */
 498 static void
 499 xpnet_dev_tx_timeout(struct net_device *dev)
 500 {
 501         dev->stats.tx_errors++;
 502 }
 503 
 504 static const struct net_device_ops xpnet_netdev_ops = {
 505         .ndo_open               = xpnet_dev_open,
 506         .ndo_stop               = xpnet_dev_stop,
 507         .ndo_start_xmit         = xpnet_dev_hard_start_xmit,
 508         .ndo_tx_timeout         = xpnet_dev_tx_timeout,
 509         .ndo_set_mac_address    = eth_mac_addr,
 510         .ndo_validate_addr      = eth_validate_addr,
 511 };
 512 
 513 static int __init
 514 xpnet_init(void)
 515 {
 516         int result;
 517 
 518         if (!is_uv())
 519                 return -ENODEV;
 520 
 521         dev_info(xpnet, "registering network device %s\n", XPNET_DEVICE_NAME);
 522 
 523         xpnet_broadcast_partitions = kcalloc(BITS_TO_LONGS(xp_max_npartitions),
 524                                              sizeof(long),
 525                                              GFP_KERNEL);
 526         if (xpnet_broadcast_partitions == NULL)
 527                 return -ENOMEM;
 528 
 529         /*
 530          * use ether_setup() to init the majority of our device
 531          * structure and then override the necessary pieces.
 532          */
 533         xpnet_device = alloc_netdev(0, XPNET_DEVICE_NAME, NET_NAME_UNKNOWN,
 534                                     ether_setup);
 535         if (xpnet_device == NULL) {
 536                 kfree(xpnet_broadcast_partitions);
 537                 return -ENOMEM;
 538         }
 539 
 540         netif_carrier_off(xpnet_device);
 541 
 542         xpnet_device->netdev_ops = &xpnet_netdev_ops;
 543         xpnet_device->mtu = XPNET_DEF_MTU;
 544         xpnet_device->min_mtu = XPNET_MIN_MTU;
 545         xpnet_device->max_mtu = XPNET_MAX_MTU;
 546 
 547         /*
 548          * Multicast assumes the LSB of the first octet is set for multicast
 549          * MAC addresses.  We chose the first octet of the MAC to be unlikely
 550          * to collide with any vendor's officially issued MAC.
 551          */
 552         xpnet_device->dev_addr[0] = 0x02;     /* locally administered, no OUI */
 553 
 554         xpnet_device->dev_addr[XPNET_PARTID_OCTET + 1] = xp_partition_id;
 555         xpnet_device->dev_addr[XPNET_PARTID_OCTET + 0] = (xp_partition_id >> 8);
 556 
 557         /*
 558          * ether_setup() sets this to a multicast device.  We are
 559          * really not supporting multicast at this time.
 560          */
 561         xpnet_device->flags &= ~IFF_MULTICAST;
 562 
 563         /*
 564          * No need to checksum as it is a DMA transfer.  The BTE will
 565          * report an error if the data is not retrievable and the
 566          * packet will be dropped.
 567          */
 568         xpnet_device->features = NETIF_F_HW_CSUM;
 569 
 570         result = register_netdev(xpnet_device);
 571         if (result != 0) {
 572                 free_netdev(xpnet_device);
 573                 kfree(xpnet_broadcast_partitions);
 574         }
 575 
 576         return result;
 577 }
 578 
 579 module_init(xpnet_init);
 580 
 581 static void __exit
 582 xpnet_exit(void)
 583 {
 584         dev_info(xpnet, "unregistering network device %s\n",
 585                  xpnet_device[0].name);
 586 
 587         unregister_netdev(xpnet_device);
 588         free_netdev(xpnet_device);
 589         kfree(xpnet_broadcast_partitions);
 590 }
 591 
 592 module_exit(xpnet_exit);
 593 
 594 MODULE_AUTHOR("Silicon Graphics, Inc.");
 595 MODULE_DESCRIPTION("Cross Partition Network adapter (XPNET)");
 596 MODULE_LICENSE("GPL");