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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 * (C) Copyright 2020 Hewlett Packard Enterprise Development LP
7 * Copyright (C) 1999-2009 Silicon Graphics, Inc. All rights reserved.
8 */
9
10/*
11 * Cross Partition Network Interface (XPNET) support
12 *
13 * XPNET provides a virtual network layered on top of the Cross
14 * Partition communication layer.
15 *
16 * XPNET provides direct point-to-point and broadcast-like support
17 * for an ethernet-like device. The ethernet broadcast medium is
18 * replaced with a point-to-point message structure which passes
19 * pointers to a DMA-capable block that a remote partition should
20 * 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 a
36 * cacheline boundary. To accomplish this, we record the number of
37 * bytes from the beginning of the first cacheline to the first useful
38 * byte of the skb (leadin_ignore) and the number of bytes from the
39 * last useful byte of the skb to the end of the last cacheline
40 * (tailout_ignore).
41 *
42 * size is the number of bytes to transfer which includes the skb->len
43 * (useful bytes of the senders skb) plus the leadin and tailout
44 */
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_SIZE
63#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 versions
72 * 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 buffer
90 * of the following type is passed as a notification cookie. When the
91 * notification function is called, we use the cookie to decide
92 * whether all outstanding message sends have completed. The skb can
93 * 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 to
104 * 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 transfer
112 * and it relies upon cache-line size transfers, we need to reserve at
113 * least one cache-line for head and tail alignment. The BTE is
114 * limited to 8MB transfers.
115 *
116 * Testing has shown that changing MTU to greater than 64KB has no effect
117 * on TCP as the two sides negotiate a Max Segment Size that is limited
118 * to 64K. Other protocols May use packets greater than this, but for
119 * 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 68
124/* 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 following
129 * octet and it consists of two octets.
130 */
131#define XPNET_PARTID_OCTET 2
132
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_name
142};
143
144static struct device *xpnet = &xpnet_dbg_subname;
145
146/*
147 * Packet was recevied by XPC and forwarded to us.
148 */
149static void
150xpnet_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 the
185 * 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 actually
193 * 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 skb
218 * !!! appears in_use and we can't just call
219 * !!! 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 in
256 * state or message reception on a connection.
257 */
258static void
259xpnet_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 int
300xpnet_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 int
327xpnet_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 and
338 * DMA'd the skb information. At this point, they are done with
339 * our side. When all recipients are done processing, we
340 * release the skb and then release our pending message structure.
341 */
342static void
343xpnet_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 void
363xpnet_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 it
404 * "on the wire". Prepare and send an xpnet_message to all partitions
405 * which have connected with us and are targets of this packet.
406 *
407 * MAC-NOTE: For the XPNET driver, the MAC address contains the
408 * destination partid. If the destination partid octets are 0xffff,
409 * this packet is to be broadcast to all connected partitions.
410 */
411static netdev_tx_t
412xpnet_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 outstanding
431 * xpc_send_notifies are relying on this skb. When none
432 * 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 one
456 * and begin sending. Any sends that happen to complete before
457 * we are done sending will not free the skb. We will be left
458 * with that task during exit. This also handles the case of
459 * 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 void
500xpnet_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 __init
515xpnet_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 device
532 * 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 multicast
551 * MAC addresses. We chose the first octet of the MAC to be unlikely
552 * 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 are
562 * 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 will
568 * report an error if the data is not retrievable and the
569 * 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 __exit
585xpnet_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");
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 * (C) Copyright 2020 Hewlett Packard Enterprise Development LP
7 * Copyright (C) 1999-2009 Silicon Graphics, Inc. All rights reserved.
8 */
9
10/*
11 * Cross Partition Network Interface (XPNET) support
12 *
13 * XPNET provides a virtual network layered on top of the Cross
14 * Partition communication layer.
15 *
16 * XPNET provides direct point-to-point and broadcast-like support
17 * for an ethernet-like device. The ethernet broadcast medium is
18 * replaced with a point-to-point message structure which passes
19 * pointers to a DMA-capable block that a remote partition should
20 * 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 a
36 * cacheline boundary. To accomplish this, we record the number of
37 * bytes from the beginning of the first cacheline to the first useful
38 * byte of the skb (leadin_ignore) and the number of bytes from the
39 * last useful byte of the skb to the end of the last cacheline
40 * (tailout_ignore).
41 *
42 * size is the number of bytes to transfer which includes the skb->len
43 * (useful bytes of the senders skb) plus the leadin and tailout
44 */
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_SIZE
63#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 versions
72 * 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 buffer
90 * of the following type is passed as a notification cookie. When the
91 * notification function is called, we use the cookie to decide
92 * whether all outstanding message sends have completed. The skb can
93 * 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 to
104 * 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 transfer
112 * and it relies upon cache-line size transfers, we need to reserve at
113 * least one cache-line for head and tail alignment. The BTE is
114 * limited to 8MB transfers.
115 *
116 * Testing has shown that changing MTU to greater than 64KB has no effect
117 * on TCP as the two sides negotiate a Max Segment Size that is limited
118 * to 64K. Other protocols May use packets greater than this, but for
119 * 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 68
124/* 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 following
129 * octet and it consists of two octets.
130 */
131#define XPNET_PARTID_OCTET 2
132
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_name
142};
143
144static struct device *xpnet = &xpnet_dbg_subname;
145
146/*
147 * Packet was recevied by XPC and forwarded to us.
148 */
149static void
150xpnet_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 the
185 * 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 actually
193 * 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 skb
218 * !!! appears in_use and we can't just call
219 * !!! 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 in
256 * state or message reception on a connection.
257 */
258static void
259xpnet_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 int
300xpnet_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 int
327xpnet_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 and
338 * DMA'd the skb information. At this point, they are done with
339 * our side. When all recipients are done processing, we
340 * release the skb and then release our pending message structure.
341 */
342static void
343xpnet_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 void
363xpnet_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 it
404 * "on the wire". Prepare and send an xpnet_message to all partitions
405 * which have connected with us and are targets of this packet.
406 *
407 * MAC-NOTE: For the XPNET driver, the MAC address contains the
408 * destination partid. If the destination partid octets are 0xffff,
409 * this packet is to be broadcast to all connected partitions.
410 */
411static netdev_tx_t
412xpnet_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 outstanding
431 * xpc_send_notifies are relying on this skb. When none
432 * 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 one
456 * and begin sending. Any sends that happen to complete before
457 * we are done sending will not free the skb. We will be left
458 * with that task during exit. This also handles the case of
459 * 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 void
500xpnet_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 __init
515xpnet_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 device
532 * 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 multicast
551 * MAC addresses. We chose the first octet of the MAC to be unlikely
552 * 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 are
562 * 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 will
568 * report an error if the data is not retrievable and the
569 * 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 __exit
585xpnet_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");