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1/*2 * This file is subject to the terms and conditions of the GNU General Public3 * License. See the file "COPYING" in the main directory of this archive4 * for more details.5 *6 * (C) Copyright 2020 Hewlett Packard Enterprise Development LP7 * Copyright (C) 1999-2009 Silicon Graphics, Inc. All rights reserved.8 */9 10/*11 * Cross Partition Network Interface (XPNET) support12 *13 * XPNET provides a virtual network layered on top of the Cross14 * Partition communication layer.15 *16 * XPNET provides direct point-to-point and broadcast-like support17 * for an ethernet-like device. The ethernet broadcast medium is18 * replaced with a point-to-point message structure which passes19 * pointers to a DMA-capable block that a remote partition should20 * retrieve and pass to the upper level networking layer.21 *22 */23 24#include <linux/slab.h>25#include <linux/module.h>26#include <linux/netdevice.h>27#include <linux/etherdevice.h>28#include "xp.h"29 30/*31 * The message payload transferred by XPC.32 *33 * buf_pa is the physical address where the DMA should pull from.34 *35 * NOTE: for performance reasons, buf_pa should _ALWAYS_ begin on a36 * cacheline boundary. To accomplish this, we record the number of37 * bytes from the beginning of the first cacheline to the first useful38 * byte of the skb (leadin_ignore) and the number of bytes from the39 * last useful byte of the skb to the end of the last cacheline40 * (tailout_ignore).41 *42 * size is the number of bytes to transfer which includes the skb->len43 * (useful bytes of the senders skb) plus the leadin and tailout44 */45struct xpnet_message {46 u16 version; /* Version for this message */47 u16 embedded_bytes; /* #of bytes embedded in XPC message */48 u32 magic; /* Special number indicating this is xpnet */49 unsigned long buf_pa; /* phys address of buffer to retrieve */50 u32 size; /* #of bytes in buffer */51 u8 leadin_ignore; /* #of bytes to ignore at the beginning */52 u8 tailout_ignore; /* #of bytes to ignore at the end */53 unsigned char data; /* body of small packets */54};55 56/*57 * Determine the size of our message, the cacheline aligned size,58 * and then the number of message will request from XPC.59 *60 * XPC expects each message to exist in an individual cacheline.61 */62#define XPNET_MSG_SIZE XPC_MSG_PAYLOAD_MAX_SIZE63#define XPNET_MSG_DATA_MAX \64 (XPNET_MSG_SIZE - offsetof(struct xpnet_message, data))65#define XPNET_MSG_NENTRIES (PAGE_SIZE / XPC_MSG_MAX_SIZE)66 67#define XPNET_MAX_KTHREADS (XPNET_MSG_NENTRIES + 1)68#define XPNET_MAX_IDLE_KTHREADS (XPNET_MSG_NENTRIES + 1)69 70/*71 * Version number of XPNET implementation. XPNET can always talk to versions72 * with same major #, and never talk to versions with a different version.73 */74#define _XPNET_VERSION(_major, _minor) (((_major) << 4) | (_minor))75#define XPNET_VERSION_MAJOR(_v) ((_v) >> 4)76#define XPNET_VERSION_MINOR(_v) ((_v) & 0xf)77 78#define XPNET_VERSION _XPNET_VERSION(1, 0) /* version 1.0 */79#define XPNET_VERSION_EMBED _XPNET_VERSION(1, 1) /* version 1.1 */80#define XPNET_MAGIC 0x88786984 /* "XNET" */81 82#define XPNET_VALID_MSG(_m) \83 ((XPNET_VERSION_MAJOR(_m->version) == XPNET_VERSION_MAJOR(XPNET_VERSION)) \84 && (msg->magic == XPNET_MAGIC))85 86#define XPNET_DEVICE_NAME "xp0"87 88/*89 * When messages are queued with xpc_send_notify, a kmalloc'd buffer90 * of the following type is passed as a notification cookie. When the91 * notification function is called, we use the cookie to decide92 * whether all outstanding message sends have completed. The skb can93 * then be released.94 */95struct xpnet_pending_msg {96 struct sk_buff *skb;97 atomic_t use_count;98};99 100static struct net_device *xpnet_device;101 102/*103 * When we are notified of other partitions activating, we add them to104 * our bitmask of partitions to which we broadcast.105 */106static unsigned long *xpnet_broadcast_partitions;107/* protect above */108static DEFINE_SPINLOCK(xpnet_broadcast_lock);109 110/*111 * Since the Block Transfer Engine (BTE) is being used for the transfer112 * and it relies upon cache-line size transfers, we need to reserve at113 * least one cache-line for head and tail alignment. The BTE is114 * limited to 8MB transfers.115 *116 * Testing has shown that changing MTU to greater than 64KB has no effect117 * on TCP as the two sides negotiate a Max Segment Size that is limited118 * to 64K. Other protocols May use packets greater than this, but for119 * now, the default is 64KB.120 */121#define XPNET_MAX_MTU (0x800000UL - L1_CACHE_BYTES)122/* 68 comes from min TCP+IP+MAC header */123#define XPNET_MIN_MTU 68124/* 32KB has been determined to be the ideal */125#define XPNET_DEF_MTU (0x8000UL)126 127/*128 * The partid is encapsulated in the MAC address beginning in the following129 * octet and it consists of two octets.130 */131#define XPNET_PARTID_OCTET 2132 133/* Define the XPNET debug device structures to be used with dev_dbg() et al */134 135static struct device_driver xpnet_dbg_name = {136 .name = "xpnet"137};138 139static struct device xpnet_dbg_subname = {140 .init_name = "", /* set to "" */141 .driver = &xpnet_dbg_name142};143 144static struct device *xpnet = &xpnet_dbg_subname;145 146/*147 * Packet was recevied by XPC and forwarded to us.148 */149static void150xpnet_receive(short partid, int channel, struct xpnet_message *msg)151{152 struct sk_buff *skb;153 void *dst;154 enum xp_retval ret;155 156 if (!XPNET_VALID_MSG(msg)) {157 /*158 * Packet with a different XPC version. Ignore.159 */160 xpc_received(partid, channel, (void *)msg);161 162 xpnet_device->stats.rx_errors++;163 164 return;165 }166 dev_dbg(xpnet, "received 0x%lx, %d, %d, %d\n", msg->buf_pa, msg->size,167 msg->leadin_ignore, msg->tailout_ignore);168 169 /* reserve an extra cache line */170 skb = dev_alloc_skb(msg->size + L1_CACHE_BYTES);171 if (!skb) {172 dev_err(xpnet, "failed on dev_alloc_skb(%d)\n",173 msg->size + L1_CACHE_BYTES);174 175 xpc_received(partid, channel, (void *)msg);176 177 xpnet_device->stats.rx_errors++;178 179 return;180 }181 182 /*183 * The allocated skb has some reserved space.184 * In order to use xp_remote_memcpy(), we need to get the185 * skb->data pointer moved forward.186 */187 skb_reserve(skb, (L1_CACHE_BYTES - ((u64)skb->data &188 (L1_CACHE_BYTES - 1)) +189 msg->leadin_ignore));190 191 /*192 * Update the tail pointer to indicate data actually193 * transferred.194 */195 skb_put(skb, (msg->size - msg->leadin_ignore - msg->tailout_ignore));196 197 /*198 * Move the data over from the other side.199 */200 if ((XPNET_VERSION_MINOR(msg->version) == 1) &&201 (msg->embedded_bytes != 0)) {202 dev_dbg(xpnet, "copying embedded message. memcpy(0x%p, 0x%p, "203 "%lu)\n", skb->data, &msg->data,204 (size_t)msg->embedded_bytes);205 206 skb_copy_to_linear_data(skb, &msg->data,207 (size_t)msg->embedded_bytes);208 } else {209 dst = (void *)((u64)skb->data & ~(L1_CACHE_BYTES - 1));210 dev_dbg(xpnet, "transferring buffer to the skb->data area;\n\t"211 "xp_remote_memcpy(0x%p, 0x%p, %u)\n", dst,212 (void *)msg->buf_pa, msg->size);213 214 ret = xp_remote_memcpy(xp_pa(dst), msg->buf_pa, msg->size);215 if (ret != xpSuccess) {216 /*217 * !!! Need better way of cleaning skb. Currently skb218 * !!! appears in_use and we can't just call219 * !!! dev_kfree_skb.220 */221 dev_err(xpnet, "xp_remote_memcpy(0x%p, 0x%p, 0x%x) "222 "returned error=0x%x\n", dst,223 (void *)msg->buf_pa, msg->size, ret);224 225 xpc_received(partid, channel, (void *)msg);226 227 xpnet_device->stats.rx_errors++;228 229 return;230 }231 }232 233 dev_dbg(xpnet, "<skb->head=0x%p skb->data=0x%p skb->tail=0x%p "234 "skb->end=0x%p skb->len=%d\n", (void *)skb->head,235 (void *)skb->data, skb_tail_pointer(skb), skb_end_pointer(skb),236 skb->len);237 238 skb->protocol = eth_type_trans(skb, xpnet_device);239 skb->ip_summed = CHECKSUM_UNNECESSARY;240 241 dev_dbg(xpnet, "passing skb to network layer\n"242 "\tskb->head=0x%p skb->data=0x%p skb->tail=0x%p "243 "skb->end=0x%p skb->len=%d\n",244 (void *)skb->head, (void *)skb->data, skb_tail_pointer(skb),245 skb_end_pointer(skb), skb->len);246 247 xpnet_device->stats.rx_packets++;248 xpnet_device->stats.rx_bytes += skb->len + ETH_HLEN;249 250 netif_rx(skb);251 xpc_received(partid, channel, (void *)msg);252}253 254/*255 * This is the handler which XPC calls during any sort of change in256 * state or message reception on a connection.257 */258static void259xpnet_connection_activity(enum xp_retval reason, short partid, int channel,260 void *data, void *key)261{262 DBUG_ON(partid < 0 || partid >= xp_max_npartitions);263 DBUG_ON(channel != XPC_NET_CHANNEL);264 265 switch (reason) {266 case xpMsgReceived: /* message received */267 DBUG_ON(data == NULL);268 269 xpnet_receive(partid, channel, (struct xpnet_message *)data);270 break;271 272 case xpConnected: /* connection completed to a partition */273 spin_lock_bh(&xpnet_broadcast_lock);274 __set_bit(partid, xpnet_broadcast_partitions);275 spin_unlock_bh(&xpnet_broadcast_lock);276 277 netif_carrier_on(xpnet_device);278 279 dev_dbg(xpnet, "%s connected to partition %d\n",280 xpnet_device->name, partid);281 break;282 283 default:284 spin_lock_bh(&xpnet_broadcast_lock);285 __clear_bit(partid, xpnet_broadcast_partitions);286 spin_unlock_bh(&xpnet_broadcast_lock);287 288 if (bitmap_empty(xpnet_broadcast_partitions,289 xp_max_npartitions)) {290 netif_carrier_off(xpnet_device);291 }292 293 dev_dbg(xpnet, "%s disconnected from partition %d\n",294 xpnet_device->name, partid);295 break;296 }297}298 299static int300xpnet_dev_open(struct net_device *dev)301{302 enum xp_retval ret;303 304 dev_dbg(xpnet, "calling xpc_connect(%d, 0x%p, NULL, %ld, %ld, %ld, "305 "%ld)\n", XPC_NET_CHANNEL, xpnet_connection_activity,306 (unsigned long)XPNET_MSG_SIZE,307 (unsigned long)XPNET_MSG_NENTRIES,308 (unsigned long)XPNET_MAX_KTHREADS,309 (unsigned long)XPNET_MAX_IDLE_KTHREADS);310 311 ret = xpc_connect(XPC_NET_CHANNEL, xpnet_connection_activity, NULL,312 XPNET_MSG_SIZE, XPNET_MSG_NENTRIES,313 XPNET_MAX_KTHREADS, XPNET_MAX_IDLE_KTHREADS);314 if (ret != xpSuccess) {315 dev_err(xpnet, "ifconfig up of %s failed on XPC connect, "316 "ret=%d\n", dev->name, ret);317 318 return -ENOMEM;319 }320 321 dev_dbg(xpnet, "ifconfig up of %s; XPC connected\n", dev->name);322 323 return 0;324}325 326static int327xpnet_dev_stop(struct net_device *dev)328{329 xpc_disconnect(XPC_NET_CHANNEL);330 331 dev_dbg(xpnet, "ifconfig down of %s; XPC disconnected\n", dev->name);332 333 return 0;334}335 336/*337 * Notification that the other end has received the message and338 * DMA'd the skb information. At this point, they are done with339 * our side. When all recipients are done processing, we340 * release the skb and then release our pending message structure.341 */342static void343xpnet_send_completed(enum xp_retval reason, short partid, int channel,344 void *__qm)345{346 struct xpnet_pending_msg *queued_msg = (struct xpnet_pending_msg *)__qm;347 348 DBUG_ON(queued_msg == NULL);349 350 dev_dbg(xpnet, "message to %d notified with reason %d\n",351 partid, reason);352 353 if (atomic_dec_return(&queued_msg->use_count) == 0) {354 dev_dbg(xpnet, "all acks for skb->head=-x%p\n",355 (void *)queued_msg->skb->head);356 357 dev_kfree_skb_any(queued_msg->skb);358 kfree(queued_msg);359 }360}361 362static void363xpnet_send(struct sk_buff *skb, struct xpnet_pending_msg *queued_msg,364 u64 start_addr, u64 end_addr, u16 embedded_bytes, int dest_partid)365{366 u8 msg_buffer[XPNET_MSG_SIZE];367 struct xpnet_message *msg = (struct xpnet_message *)&msg_buffer;368 u16 msg_size = sizeof(struct xpnet_message);369 enum xp_retval ret;370 371 msg->embedded_bytes = embedded_bytes;372 if (unlikely(embedded_bytes != 0)) {373 msg->version = XPNET_VERSION_EMBED;374 dev_dbg(xpnet, "calling memcpy(0x%p, 0x%p, 0x%lx)\n",375 &msg->data, skb->data, (size_t)embedded_bytes);376 skb_copy_from_linear_data(skb, &msg->data,377 (size_t)embedded_bytes);378 msg_size += embedded_bytes - 1;379 } else {380 msg->version = XPNET_VERSION;381 }382 msg->magic = XPNET_MAGIC;383 msg->size = end_addr - start_addr;384 msg->leadin_ignore = (u64)skb->data - start_addr;385 msg->tailout_ignore = end_addr - (u64)skb_tail_pointer(skb);386 msg->buf_pa = xp_pa((void *)start_addr);387 388 dev_dbg(xpnet, "sending XPC message to %d:%d\n"389 "msg->buf_pa=0x%lx, msg->size=%u, "390 "msg->leadin_ignore=%u, msg->tailout_ignore=%u\n",391 dest_partid, XPC_NET_CHANNEL, msg->buf_pa, msg->size,392 msg->leadin_ignore, msg->tailout_ignore);393 394 atomic_inc(&queued_msg->use_count);395 396 ret = xpc_send_notify(dest_partid, XPC_NET_CHANNEL, XPC_NOWAIT, msg,397 msg_size, xpnet_send_completed, queued_msg);398 if (unlikely(ret != xpSuccess))399 atomic_dec(&queued_msg->use_count);400}401 402/*403 * Network layer has formatted a packet (skb) and is ready to place it404 * "on the wire". Prepare and send an xpnet_message to all partitions405 * which have connected with us and are targets of this packet.406 *407 * MAC-NOTE: For the XPNET driver, the MAC address contains the408 * destination partid. If the destination partid octets are 0xffff,409 * this packet is to be broadcast to all connected partitions.410 */411static netdev_tx_t412xpnet_dev_hard_start_xmit(struct sk_buff *skb, struct net_device *dev)413{414 struct xpnet_pending_msg *queued_msg;415 u64 start_addr, end_addr;416 short dest_partid;417 u16 embedded_bytes = 0;418 419 dev_dbg(xpnet, ">skb->head=0x%p skb->data=0x%p skb->tail=0x%p "420 "skb->end=0x%p skb->len=%d\n", (void *)skb->head,421 (void *)skb->data, skb_tail_pointer(skb), skb_end_pointer(skb),422 skb->len);423 424 if (skb->data[0] == 0x33) {425 dev_kfree_skb(skb);426 return NETDEV_TX_OK; /* nothing needed to be done */427 }428 429 /*430 * The xpnet_pending_msg tracks how many outstanding431 * xpc_send_notifies are relying on this skb. When none432 * remain, release the skb.433 */434 queued_msg = kmalloc(sizeof(struct xpnet_pending_msg), GFP_ATOMIC);435 if (queued_msg == NULL) {436 dev_warn(xpnet, "failed to kmalloc %ld bytes; dropping "437 "packet\n", sizeof(struct xpnet_pending_msg));438 439 dev->stats.tx_errors++;440 dev_kfree_skb(skb);441 return NETDEV_TX_OK;442 }443 444 /* get the beginning of the first cacheline and end of last */445 start_addr = ((u64)skb->data & ~(L1_CACHE_BYTES - 1));446 end_addr = L1_CACHE_ALIGN((u64)skb_tail_pointer(skb));447 448 /* calculate how many bytes to embed in the XPC message */449 if (unlikely(skb->len <= XPNET_MSG_DATA_MAX)) {450 /* skb->data does fit so embed */451 embedded_bytes = skb->len;452 }453 454 /*455 * Since the send occurs asynchronously, we set the count to one456 * and begin sending. Any sends that happen to complete before457 * we are done sending will not free the skb. We will be left458 * with that task during exit. This also handles the case of459 * a packet destined for a partition which is no longer up.460 */461 atomic_set(&queued_msg->use_count, 1);462 queued_msg->skb = skb;463 464 if (skb->data[0] == 0xff) {465 /* we are being asked to broadcast to all partitions */466 for_each_set_bit(dest_partid, xpnet_broadcast_partitions,467 xp_max_npartitions) {468 469 xpnet_send(skb, queued_msg, start_addr, end_addr,470 embedded_bytes, dest_partid);471 }472 } else {473 dest_partid = (short)skb->data[XPNET_PARTID_OCTET + 1];474 dest_partid |= (short)skb->data[XPNET_PARTID_OCTET + 0] << 8;475 476 if (dest_partid >= 0 &&477 dest_partid < xp_max_npartitions &&478 test_bit(dest_partid, xpnet_broadcast_partitions) != 0) {479 480 xpnet_send(skb, queued_msg, start_addr, end_addr,481 embedded_bytes, dest_partid);482 }483 }484 485 dev->stats.tx_packets++;486 dev->stats.tx_bytes += skb->len;487 488 if (atomic_dec_return(&queued_msg->use_count) == 0) {489 dev_kfree_skb(skb);490 kfree(queued_msg);491 }492 493 return NETDEV_TX_OK;494}495 496/*497 * Deal with transmit timeouts coming from the network layer.498 */499static void500xpnet_dev_tx_timeout(struct net_device *dev, unsigned int txqueue)501{502 dev->stats.tx_errors++;503}504 505static const struct net_device_ops xpnet_netdev_ops = {506 .ndo_open = xpnet_dev_open,507 .ndo_stop = xpnet_dev_stop,508 .ndo_start_xmit = xpnet_dev_hard_start_xmit,509 .ndo_tx_timeout = xpnet_dev_tx_timeout,510 .ndo_set_mac_address = eth_mac_addr,511 .ndo_validate_addr = eth_validate_addr,512};513 514static int __init515xpnet_init(void)516{517 u8 addr[ETH_ALEN];518 int result;519 520 if (!is_uv_system())521 return -ENODEV;522 523 dev_info(xpnet, "registering network device %s\n", XPNET_DEVICE_NAME);524 525 xpnet_broadcast_partitions = bitmap_zalloc(xp_max_npartitions,526 GFP_KERNEL);527 if (xpnet_broadcast_partitions == NULL)528 return -ENOMEM;529 530 /*531 * use ether_setup() to init the majority of our device532 * structure and then override the necessary pieces.533 */534 xpnet_device = alloc_netdev(0, XPNET_DEVICE_NAME, NET_NAME_UNKNOWN,535 ether_setup);536 if (xpnet_device == NULL) {537 bitmap_free(xpnet_broadcast_partitions);538 return -ENOMEM;539 }540 541 netif_carrier_off(xpnet_device);542 543 xpnet_device->netdev_ops = &xpnet_netdev_ops;544 xpnet_device->mtu = XPNET_DEF_MTU;545 xpnet_device->min_mtu = XPNET_MIN_MTU;546 xpnet_device->max_mtu = XPNET_MAX_MTU;547 548 memset(addr, 0, sizeof(addr));549 /*550 * Multicast assumes the LSB of the first octet is set for multicast551 * MAC addresses. We chose the first octet of the MAC to be unlikely552 * to collide with any vendor's officially issued MAC.553 */554 addr[0] = 0x02; /* locally administered, no OUI */555 556 addr[XPNET_PARTID_OCTET + 1] = xp_partition_id;557 addr[XPNET_PARTID_OCTET + 0] = (xp_partition_id >> 8);558 eth_hw_addr_set(xpnet_device, addr);559 560 /*561 * ether_setup() sets this to a multicast device. We are562 * really not supporting multicast at this time.563 */564 xpnet_device->flags &= ~IFF_MULTICAST;565 566 /*567 * No need to checksum as it is a DMA transfer. The BTE will568 * report an error if the data is not retrievable and the569 * packet will be dropped.570 */571 xpnet_device->features = NETIF_F_HW_CSUM;572 573 result = register_netdev(xpnet_device);574 if (result != 0) {575 free_netdev(xpnet_device);576 bitmap_free(xpnet_broadcast_partitions);577 }578 579 return result;580}581 582module_init(xpnet_init);583 584static void __exit585xpnet_exit(void)586{587 dev_info(xpnet, "unregistering network device %s\n",588 xpnet_device[0].name);589 590 unregister_netdev(xpnet_device);591 free_netdev(xpnet_device);592 bitmap_free(xpnet_broadcast_partitions);593}594 595module_exit(xpnet_exit);596 597MODULE_AUTHOR("Silicon Graphics, Inc.");598MODULE_DESCRIPTION("Cross Partition Network adapter (XPNET)");599MODULE_LICENSE("GPL");600