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
6 * Copyright (C) 1999-2009 Silicon Graphics, Inc. All rights reserved.
10 * Cross Partition Network Interface (XPNET) support
12 * XPNET provides a virtual network layered on top of the Cross
13 * Partition communication layer.
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.
23 #include <linux/module.h>
24 #include <linux/netdevice.h>
25 #include <linux/etherdevice.h>
29 * The message payload transferred by XPC.
31 * buf_pa is the physical address where the DMA should pull from.
33 * NOTE: for performance reasons, buf_pa should _ALWAYS_ begin on a
34 * cacheline boundary. To accomplish this, we record the number of
35 * bytes from the beginning of the first cacheline to the first useful
36 * byte of the skb (leadin_ignore) and the number of bytes from the
37 * last useful byte of the skb to the end of the last cacheline
40 * size is the number of bytes to transfer which includes the skb->len
41 * (useful bytes of the senders skb) plus the leadin and tailout
43 struct xpnet_message
{
44 u16 version
; /* Version for this message */
45 u16 embedded_bytes
; /* #of bytes embedded in XPC message */
46 u32 magic
; /* Special number indicating this is xpnet */
47 unsigned long buf_pa
; /* phys address of buffer to retrieve */
48 u32 size
; /* #of bytes in buffer */
49 u8 leadin_ignore
; /* #of bytes to ignore at the beginning */
50 u8 tailout_ignore
; /* #of bytes to ignore at the end */
51 unsigned char data
; /* body of small packets */
55 * Determine the size of our message, the cacheline aligned size,
56 * and then the number of message will request from XPC.
58 * XPC expects each message to exist in an individual cacheline.
60 #define XPNET_MSG_SIZE XPC_MSG_PAYLOAD_MAX_SIZE
61 #define XPNET_MSG_DATA_MAX \
62 (XPNET_MSG_SIZE - offsetof(struct xpnet_message, data))
63 #define XPNET_MSG_NENTRIES (PAGE_SIZE / XPC_MSG_MAX_SIZE)
65 #define XPNET_MAX_KTHREADS (XPNET_MSG_NENTRIES + 1)
66 #define XPNET_MAX_IDLE_KTHREADS (XPNET_MSG_NENTRIES + 1)
69 * Version number of XPNET implementation. XPNET can always talk to versions
70 * with same major #, and never talk to versions with a different version.
72 #define _XPNET_VERSION(_major, _minor) (((_major) << 4) | (_minor))
73 #define XPNET_VERSION_MAJOR(_v) ((_v) >> 4)
74 #define XPNET_VERSION_MINOR(_v) ((_v) & 0xf)
76 #define XPNET_VERSION _XPNET_VERSION(1, 0) /* version 1.0 */
77 #define XPNET_VERSION_EMBED _XPNET_VERSION(1, 1) /* version 1.1 */
78 #define XPNET_MAGIC 0x88786984 /* "XNET" */
80 #define XPNET_VALID_MSG(_m) \
81 ((XPNET_VERSION_MAJOR(_m->version) == XPNET_VERSION_MAJOR(XPNET_VERSION)) \
82 && (msg->magic == XPNET_MAGIC))
84 #define XPNET_DEVICE_NAME "xp0"
87 * When messages are queued with xpc_send_notify, a kmalloc'd buffer
88 * of the following type is passed as a notification cookie. When the
89 * notification function is called, we use the cookie to decide
90 * whether all outstanding message sends have completed. The skb can
93 struct xpnet_pending_msg
{
98 struct net_device
*xpnet_device
;
101 * When we are notified of other partitions activating, we add them to
102 * our bitmask of partitions to which we broadcast.
104 static unsigned long *xpnet_broadcast_partitions
;
106 static DEFINE_SPINLOCK(xpnet_broadcast_lock
);
109 * Since the Block Transfer Engine (BTE) is being used for the transfer
110 * and it relies upon cache-line size transfers, we need to reserve at
111 * least one cache-line for head and tail alignment. The BTE is
112 * limited to 8MB transfers.
114 * Testing has shown that changing MTU to greater than 64KB has no effect
115 * on TCP as the two sides negotiate a Max Segment Size that is limited
116 * to 64K. Other protocols May use packets greater than this, but for
117 * now, the default is 64KB.
119 #define XPNET_MAX_MTU (0x800000UL - L1_CACHE_BYTES)
120 /* 32KB has been determined to be the ideal */
121 #define XPNET_DEF_MTU (0x8000UL)
124 * The partid is encapsulated in the MAC address beginning in the following
125 * octet and it consists of two octets.
127 #define XPNET_PARTID_OCTET 2
129 /* Define the XPNET debug device structures to be used with dev_dbg() et al */
131 struct device_driver xpnet_dbg_name
= {
135 struct device xpnet_dbg_subname
= {
136 .init_name
= "", /* set to "" */
137 .driver
= &xpnet_dbg_name
140 struct device
*xpnet
= &xpnet_dbg_subname
;
143 * Packet was recevied by XPC and forwarded to us.
146 xpnet_receive(short partid
, int channel
, struct xpnet_message
*msg
)
152 if (!XPNET_VALID_MSG(msg
)) {
154 * Packet with a different XPC version. Ignore.
156 xpc_received(partid
, channel
, (void *)msg
);
158 xpnet_device
->stats
.rx_errors
++;
162 dev_dbg(xpnet
, "received 0x%lx, %d, %d, %d\n", msg
->buf_pa
, msg
->size
,
163 msg
->leadin_ignore
, msg
->tailout_ignore
);
165 /* reserve an extra cache line */
166 skb
= dev_alloc_skb(msg
->size
+ L1_CACHE_BYTES
);
168 dev_err(xpnet
, "failed on dev_alloc_skb(%d)\n",
169 msg
->size
+ L1_CACHE_BYTES
);
171 xpc_received(partid
, channel
, (void *)msg
);
173 xpnet_device
->stats
.rx_errors
++;
179 * The allocated skb has some reserved space.
180 * In order to use xp_remote_memcpy(), we need to get the
181 * skb->data pointer moved forward.
183 skb_reserve(skb
, (L1_CACHE_BYTES
- ((u64
)skb
->data
&
184 (L1_CACHE_BYTES
- 1)) +
185 msg
->leadin_ignore
));
188 * Update the tail pointer to indicate data actually
191 skb_put(skb
, (msg
->size
- msg
->leadin_ignore
- msg
->tailout_ignore
));
194 * Move the data over from the other side.
196 if ((XPNET_VERSION_MINOR(msg
->version
) == 1) &&
197 (msg
->embedded_bytes
!= 0)) {
198 dev_dbg(xpnet
, "copying embedded message. memcpy(0x%p, 0x%p, "
199 "%lu)\n", skb
->data
, &msg
->data
,
200 (size_t)msg
->embedded_bytes
);
202 skb_copy_to_linear_data(skb
, &msg
->data
,
203 (size_t)msg
->embedded_bytes
);
205 dst
= (void *)((u64
)skb
->data
& ~(L1_CACHE_BYTES
- 1));
206 dev_dbg(xpnet
, "transferring buffer to the skb->data area;\n\t"
207 "xp_remote_memcpy(0x%p, 0x%p, %hu)\n", dst
,
208 (void *)msg
->buf_pa
, msg
->size
);
210 ret
= xp_remote_memcpy(xp_pa(dst
), msg
->buf_pa
, msg
->size
);
211 if (ret
!= xpSuccess
) {
213 * !!! Need better way of cleaning skb. Currently skb
214 * !!! appears in_use and we can't just call
217 dev_err(xpnet
, "xp_remote_memcpy(0x%p, 0x%p, 0x%hx) "
218 "returned error=0x%x\n", dst
,
219 (void *)msg
->buf_pa
, msg
->size
, ret
);
221 xpc_received(partid
, channel
, (void *)msg
);
223 xpnet_device
->stats
.rx_errors
++;
229 dev_dbg(xpnet
, "<skb->head=0x%p skb->data=0x%p skb->tail=0x%p "
230 "skb->end=0x%p skb->len=%d\n", (void *)skb
->head
,
231 (void *)skb
->data
, skb_tail_pointer(skb
), skb_end_pointer(skb
),
234 skb
->protocol
= eth_type_trans(skb
, xpnet_device
);
235 skb
->ip_summed
= CHECKSUM_UNNECESSARY
;
237 dev_dbg(xpnet
, "passing skb to network layer\n"
238 "\tskb->head=0x%p skb->data=0x%p skb->tail=0x%p "
239 "skb->end=0x%p skb->len=%d\n",
240 (void *)skb
->head
, (void *)skb
->data
, skb_tail_pointer(skb
),
241 skb_end_pointer(skb
), skb
->len
);
243 xpnet_device
->last_rx
= jiffies
;
244 xpnet_device
->stats
.rx_packets
++;
245 xpnet_device
->stats
.rx_bytes
+= skb
->len
+ ETH_HLEN
;
248 xpc_received(partid
, channel
, (void *)msg
);
252 * This is the handler which XPC calls during any sort of change in
253 * state or message reception on a connection.
256 xpnet_connection_activity(enum xp_retval reason
, short partid
, int channel
,
257 void *data
, void *key
)
259 DBUG_ON(partid
< 0 || partid
>= xp_max_npartitions
);
260 DBUG_ON(channel
!= XPC_NET_CHANNEL
);
263 case xpMsgReceived
: /* message received */
264 DBUG_ON(data
== NULL
);
266 xpnet_receive(partid
, channel
, (struct xpnet_message
*)data
);
269 case xpConnected
: /* connection completed to a partition */
270 spin_lock_bh(&xpnet_broadcast_lock
);
271 __set_bit(partid
, xpnet_broadcast_partitions
);
272 spin_unlock_bh(&xpnet_broadcast_lock
);
274 netif_carrier_on(xpnet_device
);
276 dev_dbg(xpnet
, "%s connected to partition %d\n",
277 xpnet_device
->name
, partid
);
281 spin_lock_bh(&xpnet_broadcast_lock
);
282 __clear_bit(partid
, xpnet_broadcast_partitions
);
283 spin_unlock_bh(&xpnet_broadcast_lock
);
285 if (bitmap_empty((unsigned long *)xpnet_broadcast_partitions
,
286 xp_max_npartitions
)) {
287 netif_carrier_off(xpnet_device
);
290 dev_dbg(xpnet
, "%s disconnected from partition %d\n",
291 xpnet_device
->name
, partid
);
297 xpnet_dev_open(struct net_device
*dev
)
301 dev_dbg(xpnet
, "calling xpc_connect(%d, 0x%p, NULL, %ld, %ld, %ld, "
302 "%ld)\n", XPC_NET_CHANNEL
, xpnet_connection_activity
,
303 (unsigned long)XPNET_MSG_SIZE
,
304 (unsigned long)XPNET_MSG_NENTRIES
,
305 (unsigned long)XPNET_MAX_KTHREADS
,
306 (unsigned long)XPNET_MAX_IDLE_KTHREADS
);
308 ret
= xpc_connect(XPC_NET_CHANNEL
, xpnet_connection_activity
, NULL
,
309 XPNET_MSG_SIZE
, XPNET_MSG_NENTRIES
,
310 XPNET_MAX_KTHREADS
, XPNET_MAX_IDLE_KTHREADS
);
311 if (ret
!= xpSuccess
) {
312 dev_err(xpnet
, "ifconfig up of %s failed on XPC connect, "
313 "ret=%d\n", dev
->name
, ret
);
318 dev_dbg(xpnet
, "ifconfig up of %s; XPC connected\n", dev
->name
);
324 xpnet_dev_stop(struct net_device
*dev
)
326 xpc_disconnect(XPC_NET_CHANNEL
);
328 dev_dbg(xpnet
, "ifconfig down of %s; XPC disconnected\n", dev
->name
);
334 xpnet_dev_change_mtu(struct net_device
*dev
, int new_mtu
)
336 /* 68 comes from min TCP+IP+MAC header */
337 if ((new_mtu
< 68) || (new_mtu
> XPNET_MAX_MTU
)) {
338 dev_err(xpnet
, "ifconfig %s mtu %d failed; value must be "
339 "between 68 and %ld\n", dev
->name
, new_mtu
,
345 dev_dbg(xpnet
, "ifconfig %s mtu set to %d\n", dev
->name
, new_mtu
);
350 * Notification that the other end has received the message and
351 * DMA'd the skb information. At this point, they are done with
352 * our side. When all recipients are done processing, we
353 * release the skb and then release our pending message structure.
356 xpnet_send_completed(enum xp_retval reason
, short partid
, int channel
,
359 struct xpnet_pending_msg
*queued_msg
= (struct xpnet_pending_msg
*)__qm
;
361 DBUG_ON(queued_msg
== NULL
);
363 dev_dbg(xpnet
, "message to %d notified with reason %d\n",
366 if (atomic_dec_return(&queued_msg
->use_count
) == 0) {
367 dev_dbg(xpnet
, "all acks for skb->head=-x%p\n",
368 (void *)queued_msg
->skb
->head
);
370 dev_kfree_skb_any(queued_msg
->skb
);
376 xpnet_send(struct sk_buff
*skb
, struct xpnet_pending_msg
*queued_msg
,
377 u64 start_addr
, u64 end_addr
, u16 embedded_bytes
, int dest_partid
)
379 u8 msg_buffer
[XPNET_MSG_SIZE
];
380 struct xpnet_message
*msg
= (struct xpnet_message
*)&msg_buffer
;
381 u16 msg_size
= sizeof(struct xpnet_message
);
384 msg
->embedded_bytes
= embedded_bytes
;
385 if (unlikely(embedded_bytes
!= 0)) {
386 msg
->version
= XPNET_VERSION_EMBED
;
387 dev_dbg(xpnet
, "calling memcpy(0x%p, 0x%p, 0x%lx)\n",
388 &msg
->data
, skb
->data
, (size_t)embedded_bytes
);
389 skb_copy_from_linear_data(skb
, &msg
->data
,
390 (size_t)embedded_bytes
);
391 msg_size
+= embedded_bytes
- 1;
393 msg
->version
= XPNET_VERSION
;
395 msg
->magic
= XPNET_MAGIC
;
396 msg
->size
= end_addr
- start_addr
;
397 msg
->leadin_ignore
= (u64
)skb
->data
- start_addr
;
398 msg
->tailout_ignore
= end_addr
- (u64
)skb_tail_pointer(skb
);
399 msg
->buf_pa
= xp_pa((void *)start_addr
);
401 dev_dbg(xpnet
, "sending XPC message to %d:%d\n"
402 "msg->buf_pa=0x%lx, msg->size=%u, "
403 "msg->leadin_ignore=%u, msg->tailout_ignore=%u\n",
404 dest_partid
, XPC_NET_CHANNEL
, msg
->buf_pa
, msg
->size
,
405 msg
->leadin_ignore
, msg
->tailout_ignore
);
407 atomic_inc(&queued_msg
->use_count
);
409 ret
= xpc_send_notify(dest_partid
, XPC_NET_CHANNEL
, XPC_NOWAIT
, msg
,
410 msg_size
, xpnet_send_completed
, queued_msg
);
411 if (unlikely(ret
!= xpSuccess
))
412 atomic_dec(&queued_msg
->use_count
);
416 * Network layer has formatted a packet (skb) and is ready to place it
417 * "on the wire". Prepare and send an xpnet_message to all partitions
418 * which have connected with us and are targets of this packet.
420 * MAC-NOTE: For the XPNET driver, the MAC address contains the
421 * destination partid. If the destination partid octets are 0xffff,
422 * this packet is to be broadcast to all connected partitions.
425 xpnet_dev_hard_start_xmit(struct sk_buff
*skb
, struct net_device
*dev
)
427 struct xpnet_pending_msg
*queued_msg
;
428 u64 start_addr
, end_addr
;
430 u16 embedded_bytes
= 0;
432 dev_dbg(xpnet
, ">skb->head=0x%p skb->data=0x%p skb->tail=0x%p "
433 "skb->end=0x%p skb->len=%d\n", (void *)skb
->head
,
434 (void *)skb
->data
, skb_tail_pointer(skb
), skb_end_pointer(skb
),
437 if (skb
->data
[0] == 0x33) {
439 return 0; /* nothing needed to be done */
443 * The xpnet_pending_msg tracks how many outstanding
444 * xpc_send_notifies are relying on this skb. When none
445 * remain, release the skb.
447 queued_msg
= kmalloc(sizeof(struct xpnet_pending_msg
), GFP_ATOMIC
);
448 if (queued_msg
== NULL
) {
449 dev_warn(xpnet
, "failed to kmalloc %ld bytes; dropping "
450 "packet\n", sizeof(struct xpnet_pending_msg
));
452 dev
->stats
.tx_errors
++;
457 /* get the beginning of the first cacheline and end of last */
458 start_addr
= ((u64
)skb
->data
& ~(L1_CACHE_BYTES
- 1));
459 end_addr
= L1_CACHE_ALIGN((u64
)skb_tail_pointer(skb
));
461 /* calculate how many bytes to embed in the XPC message */
462 if (unlikely(skb
->len
<= XPNET_MSG_DATA_MAX
)) {
463 /* skb->data does fit so embed */
464 embedded_bytes
= skb
->len
;
468 * Since the send occurs asynchronously, we set the count to one
469 * and begin sending. Any sends that happen to complete before
470 * we are done sending will not free the skb. We will be left
471 * with that task during exit. This also handles the case of
472 * a packet destined for a partition which is no longer up.
474 atomic_set(&queued_msg
->use_count
, 1);
475 queued_msg
->skb
= skb
;
477 if (skb
->data
[0] == 0xff) {
478 /* we are being asked to broadcast to all partitions */
479 for_each_bit(dest_partid
, xpnet_broadcast_partitions
,
480 xp_max_npartitions
) {
482 xpnet_send(skb
, queued_msg
, start_addr
, end_addr
,
483 embedded_bytes
, dest_partid
);
486 dest_partid
= (short)skb
->data
[XPNET_PARTID_OCTET
+ 1];
487 dest_partid
|= (short)skb
->data
[XPNET_PARTID_OCTET
+ 0] << 8;
489 if (dest_partid
>= 0 &&
490 dest_partid
< xp_max_npartitions
&&
491 test_bit(dest_partid
, xpnet_broadcast_partitions
) != 0) {
493 xpnet_send(skb
, queued_msg
, start_addr
, end_addr
,
494 embedded_bytes
, dest_partid
);
498 if (atomic_dec_return(&queued_msg
->use_count
) == 0) {
503 dev
->stats
.tx_packets
++;
504 dev
->stats
.tx_bytes
+= skb
->len
;
510 * Deal with transmit timeouts coming from the network layer.
513 xpnet_dev_tx_timeout(struct net_device
*dev
)
515 dev
->stats
.tx_errors
++;
518 static const struct net_device_ops xpnet_netdev_ops
= {
519 .ndo_open
= xpnet_dev_open
,
520 .ndo_stop
= xpnet_dev_stop
,
521 .ndo_start_xmit
= xpnet_dev_hard_start_xmit
,
522 .ndo_change_mtu
= xpnet_dev_change_mtu
,
523 .ndo_tx_timeout
= xpnet_dev_tx_timeout
,
524 .ndo_set_mac_address
= eth_mac_addr
,
525 .ndo_validate_addr
= eth_validate_addr
,
533 if (!is_shub() && !is_uv())
536 dev_info(xpnet
, "registering network device %s\n", XPNET_DEVICE_NAME
);
538 xpnet_broadcast_partitions
= kzalloc(BITS_TO_LONGS(xp_max_npartitions
) *
539 sizeof(long), GFP_KERNEL
);
540 if (xpnet_broadcast_partitions
== NULL
)
544 * use ether_setup() to init the majority of our device
545 * structure and then override the necessary pieces.
547 xpnet_device
= alloc_netdev(0, XPNET_DEVICE_NAME
, ether_setup
);
548 if (xpnet_device
== NULL
) {
549 kfree(xpnet_broadcast_partitions
);
553 netif_carrier_off(xpnet_device
);
555 xpnet_device
->netdev_ops
= &xpnet_netdev_ops
;
556 xpnet_device
->mtu
= XPNET_DEF_MTU
;
559 * Multicast assumes the LSB of the first octet is set for multicast
560 * MAC addresses. We chose the first octet of the MAC to be unlikely
561 * to collide with any vendor's officially issued MAC.
563 xpnet_device
->dev_addr
[0] = 0x02; /* locally administered, no OUI */
565 xpnet_device
->dev_addr
[XPNET_PARTID_OCTET
+ 1] = xp_partition_id
;
566 xpnet_device
->dev_addr
[XPNET_PARTID_OCTET
+ 0] = (xp_partition_id
>> 8);
569 * ether_setup() sets this to a multicast device. We are
570 * really not supporting multicast at this time.
572 xpnet_device
->flags
&= ~IFF_MULTICAST
;
575 * No need to checksum as it is a DMA transfer. The BTE will
576 * report an error if the data is not retrievable and the
577 * packet will be dropped.
579 xpnet_device
->features
= NETIF_F_NO_CSUM
;
581 result
= register_netdev(xpnet_device
);
583 free_netdev(xpnet_device
);
584 kfree(xpnet_broadcast_partitions
);
590 module_init(xpnet_init
);
595 dev_info(xpnet
, "unregistering network device %s\n",
596 xpnet_device
[0].name
);
598 unregister_netdev(xpnet_device
);
599 free_netdev(xpnet_device
);
600 kfree(xpnet_broadcast_partitions
);
603 module_exit(xpnet_exit
);
605 MODULE_AUTHOR("Silicon Graphics, Inc.");
606 MODULE_DESCRIPTION("Cross Partition Network adapter (XPNET)");
607 MODULE_LICENSE("GPL");