xref: /titanic_41/usr/src/uts/common/io/rge/rge_rxtx.c (revision 60405de4d8688d96dd05157c28db3ade5c9bc234)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 /*
22  * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
23  * Use is subject to license terms.
24  */
25 
26 #pragma ident	"%Z%%M%	%I%	%E% SMI"
27 
28 #include "rge.h"
29 
30 #define	U32TOPTR(x)	((void *)(uintptr_t)(uint32_t)(x))
31 #define	PTRTOU32(x)	((uint32_t)(uintptr_t)(void *)(x))
32 
33 /*
34  * ========== RX side routines ==========
35  */
36 
37 #define	RGE_DBG		RGE_DBG_RECV	/* debug flag for this code	*/
38 
39 static uint32_t rge_atomic_reserve(uint32_t *count_p, uint32_t n);
40 #pragma	inline(rge_atomic_reserve)
41 
42 static uint32_t
43 rge_atomic_reserve(uint32_t *count_p, uint32_t n)
44 {
45 	uint32_t oldval;
46 	uint32_t newval;
47 
48 	/* ATOMICALLY */
49 	do {
50 		oldval = *count_p;
51 		newval = oldval - n;
52 		if (oldval <= n)
53 			return (0);		/* no resources left	*/
54 	} while (cas32(count_p, oldval, newval) != oldval);
55 
56 	return (newval);
57 }
58 
59 /*
60  * Atomically increment a counter
61  */
62 static void rge_atomic_renounce(uint32_t *count_p, uint32_t n);
63 #pragma	inline(rge_atomic_renounce)
64 
65 static void
66 rge_atomic_renounce(uint32_t *count_p, uint32_t n)
67 {
68 	uint32_t oldval;
69 	uint32_t newval;
70 
71 	/* ATOMICALLY */
72 	do {
73 		oldval = *count_p;
74 		newval = oldval + n;
75 	} while (cas32(count_p, oldval, newval) != oldval);
76 }
77 
78 /*
79  * Callback code invoked from STREAMs when the recv data buffer is free
80  * for recycling.
81  */
82 void
83 rge_rx_recycle(caddr_t arg)
84 {
85 	rge_t *rgep;
86 	dma_buf_t *rx_buf;
87 	sw_rbd_t *free_srbdp;
88 	uint32_t slot_recy;
89 
90 	rx_buf = (dma_buf_t *)arg;
91 	rgep = (rge_t *)rx_buf->private;
92 
93 	/*
94 	 * In rge_unattach() and rge_attach(), this callback function will
95 	 * also be called to free mp in rge_fini_rings() and rge_init_rings().
96 	 * In such situation, we shouldn't do below desballoc(), otherwise,
97 	 * there'll be memory leak.
98 	 */
99 	if (rgep->rge_mac_state == RGE_MAC_UNATTACH ||
100 	    rgep->rge_mac_state == RGE_MAC_ATTACH)
101 		return;
102 
103 	/*
104 	 * Recycle the data buffer again
105 	 * and fill them in free ring
106 	 */
107 	rx_buf->mp = desballoc(DMA_VPTR(rx_buf->pbuf),
108 	    rgep->rxbuf_size, 0, &rx_buf->rx_recycle);
109 	if (rx_buf->mp == NULL) {
110 		rge_problem(rgep, "rge_rx_recycle: desballoc() failed");
111 		return;
112 	}
113 	mutex_enter(rgep->rc_lock);
114 	slot_recy = rgep->rc_next;
115 	free_srbdp = &rgep->free_srbds[slot_recy];
116 
117 	ASSERT(free_srbdp->rx_buf == NULL);
118 	free_srbdp->rx_buf = rx_buf;
119 	rgep->rc_next = NEXT(slot_recy, RGE_BUF_SLOTS);
120 	rge_atomic_renounce(&rgep->rx_free, 1);
121 	if (rgep->rx_bcopy && rgep->rx_free == RGE_BUF_SLOTS)
122 		rgep->rx_bcopy = B_FALSE;
123 	ASSERT(rgep->rx_free <= RGE_BUF_SLOTS);
124 
125 	mutex_exit(rgep->rc_lock);
126 }
127 
128 static int rge_rx_refill(rge_t *rgep, uint32_t slot);
129 #pragma	inline(rge_rx_refill)
130 
131 static int
132 rge_rx_refill(rge_t *rgep, uint32_t slot)
133 {
134 	dma_buf_t *free_buf;
135 	rge_bd_t *hw_rbd_p;
136 	sw_rbd_t *srbdp;
137 	uint32_t free_slot;
138 
139 	srbdp = &rgep->sw_rbds[slot];
140 	hw_rbd_p = &rgep->rx_ring[slot];
141 	free_slot = rgep->rf_next;
142 	free_buf = rgep->free_srbds[free_slot].rx_buf;
143 	if (free_buf != NULL) {
144 		srbdp->rx_buf = free_buf;
145 		rgep->free_srbds[free_slot].rx_buf = NULL;
146 		hw_rbd_p->host_buf_addr = RGE_BSWAP_32(rgep->head_room +
147 		    + free_buf->pbuf.cookie.dmac_laddress);
148 		hw_rbd_p->host_buf_addr_hi =
149 		    RGE_BSWAP_32(free_buf->pbuf.cookie.dmac_laddress >> 32);
150 		rgep->rf_next = NEXT(free_slot, RGE_BUF_SLOTS);
151 		return (1);
152 	} else {
153 		/*
154 		 * This situation shouldn't happen
155 		 */
156 		rge_problem(rgep, "rge_rx_refill: free buffer %d is NULL",
157 		    free_slot);
158 		rgep->rx_bcopy = B_TRUE;
159 		return (0);
160 	}
161 }
162 
163 static mblk_t *rge_receive_packet(rge_t *rgep, uint32_t slot);
164 #pragma	inline(rge_receive_packet)
165 
166 static mblk_t *
167 rge_receive_packet(rge_t *rgep, uint32_t slot)
168 {
169 	rge_bd_t *hw_rbd_p;
170 	sw_rbd_t *srbdp;
171 	uchar_t *dp;
172 	mblk_t *mp;
173 	uint8_t *rx_ptr;
174 	uint32_t rx_status;
175 	uint_t packet_len;
176 	uint_t minsize;
177 	uint_t maxsize;
178 	uint32_t proto;
179 	uint32_t pflags;
180 	struct ether_vlan_header *ehp;
181 	uint16_t vtag = 0;
182 
183 	hw_rbd_p = &rgep->rx_ring[slot];
184 	srbdp = &rgep->sw_rbds[slot];
185 
186 	/*
187 	 * Read receive status
188 	 */
189 	rx_status = RGE_BSWAP_32(hw_rbd_p->flags_len) & RBD_FLAGS_MASK;
190 
191 	/*
192 	 * Handle error packet
193 	 */
194 	if (!(rx_status & BD_FLAG_PKT_END)) {
195 		RGE_DEBUG(("rge_receive_packet: not a complete packat"));
196 		return (NULL);
197 	}
198 	if (rx_status & RBD_FLAG_ERROR) {
199 		if (rx_status & RBD_FLAG_CRC_ERR)
200 			rgep->stats.crc_err++;
201 		if (rx_status & RBD_FLAG_RUNT)
202 			rgep->stats.in_short++;
203 		/*
204 		 * Set chip_error flag to reset chip:
205 		 * (suggested in Realtek programming guide.)
206 		 */
207 		RGE_DEBUG(("rge_receive_packet: error packet, status = %x",
208 		    rx_status));
209 		mutex_enter(rgep->genlock);
210 		rgep->rge_chip_state = RGE_CHIP_ERROR;
211 		mutex_exit(rgep->genlock);
212 		return (NULL);
213 	}
214 
215 	/*
216 	 * Handle size error packet
217 	 */
218 	packet_len = RGE_BSWAP_32(hw_rbd_p->flags_len) & RBD_LEN_MASK;
219 	packet_len -= ETHERFCSL;
220 	minsize = ETHERMIN;
221 	pflags = RGE_BSWAP_32(hw_rbd_p->vlan_tag);
222 	if (pflags & RBD_VLAN_PKT)
223 		minsize -= VLAN_TAGSZ;
224 	maxsize = rgep->ethmax_size;
225 	if (packet_len < minsize || packet_len > maxsize) {
226 		RGE_DEBUG(("rge_receive_packet: len err = %d", packet_len));
227 		return (NULL);
228 	}
229 
230 	DMA_SYNC(srbdp->rx_buf->pbuf, DDI_DMA_SYNC_FORKERNEL);
231 	if (rgep->rx_bcopy || packet_len <= RGE_RECV_COPY_SIZE ||
232 	    !rge_atomic_reserve(&rgep->rx_free, 1)) {
233 		/*
234 		 * Allocate buffer to receive this good packet
235 		 */
236 		mp = allocb(packet_len + RGE_HEADROOM, 0);
237 		if (mp == NULL) {
238 			RGE_DEBUG(("rge_receive_packet: allocate buffer fail"));
239 			rgep->stats.no_rcvbuf++;
240 			return (NULL);
241 		}
242 
243 		/*
244 		 * Copy the data found into the new cluster
245 		 */
246 		rx_ptr = DMA_VPTR(srbdp->rx_buf->pbuf);
247 		mp->b_rptr = dp = mp->b_rptr + RGE_HEADROOM;
248 		bcopy(rx_ptr + rgep->head_room, dp, packet_len);
249 		mp->b_wptr = dp + packet_len;
250 	} else {
251 		mp = srbdp->rx_buf->mp;
252 		mp->b_rptr += rgep->head_room;
253 		mp->b_wptr = mp->b_rptr + packet_len;
254 		mp->b_next = mp->b_cont = NULL;
255 		/*
256 		 * Refill the current receive bd buffer
257 		 *   if fails, will just keep the mp.
258 		 */
259 		if (!rge_rx_refill(rgep, slot))
260 			return (NULL);
261 	}
262 	rgep->stats.rbytes += packet_len;
263 
264 	/*
265 	 * VLAN packet ?
266 	 */
267 	if (pflags & RBD_VLAN_PKT)
268 		vtag = pflags & RBD_VLAN_TAG;
269 	if (vtag) {
270 		vtag = TCI_CHIP2OS(vtag);
271 		/*
272 		 * As h/w strips the VLAN tag from incoming packet, we need
273 		 * insert VLAN tag into this packet before send up here.
274 		 */
275 		(void) memmove(mp->b_rptr - VLAN_TAGSZ, mp->b_rptr,
276 		    2 * ETHERADDRL);
277 		mp->b_rptr -= VLAN_TAGSZ;
278 		ehp = (struct ether_vlan_header *)mp->b_rptr;
279 		ehp->ether_tpid = htons(ETHERTYPE_VLAN);
280 		ehp->ether_tci = htons(vtag);
281 		rgep->stats.rbytes += VLAN_TAGSZ;
282 	}
283 
284 	/*
285 	 * Check h/w checksum offload status
286 	 */
287 	pflags = 0;
288 	proto = rx_status & RBD_FLAG_PROTOCOL;
289 	if ((proto == RBD_FLAG_TCP && !(rx_status & RBD_TCP_CKSUM_ERR)) ||
290 	    (proto == RBD_FLAG_UDP && !(rx_status & RBD_UDP_CKSUM_ERR)))
291 		pflags |= HCK_FULLCKSUM | HCK_FULLCKSUM_OK;
292 	if (proto != RBD_FLAG_NONE_IP && !(rx_status & RBD_IP_CKSUM_ERR))
293 		pflags |= HCK_IPV4_HDRCKSUM;
294 	if (pflags != 0)  {
295 		(void) hcksum_assoc(mp, NULL, NULL, 0, 0, 0, 0, pflags, 0);
296 	}
297 
298 	return (mp);
299 }
300 
301 /*
302  * Accept the packets received in rx ring.
303  *
304  * Returns a chain of mblks containing the received data, to be
305  * passed up to mac_rx().
306  * The routine returns only when a complete scan has been performed
307  * without finding any packets to receive.
308  * This function must SET the OWN bit of BD to indicate the packets
309  * it has accepted from the ring.
310  */
311 static mblk_t *rge_receive_ring(rge_t *rgep);
312 #pragma	inline(rge_receive_ring)
313 
314 static mblk_t *
315 rge_receive_ring(rge_t *rgep)
316 {
317 	rge_bd_t *hw_rbd_p;
318 	mblk_t *head;
319 	mblk_t **tail;
320 	mblk_t *mp;
321 	uint32_t slot;
322 
323 	ASSERT(mutex_owned(rgep->rx_lock));
324 
325 	/*
326 	 * Sync (all) the receive ring descriptors
327 	 * before accepting the packets they describe
328 	 */
329 	DMA_SYNC(rgep->rx_desc, DDI_DMA_SYNC_FORKERNEL);
330 	slot = rgep->rx_next;
331 	hw_rbd_p = &rgep->rx_ring[slot];
332 	head = NULL;
333 	tail = &head;
334 
335 	while (!(hw_rbd_p->flags_len & RGE_BSWAP_32(BD_FLAG_HW_OWN))) {
336 		if ((mp = rge_receive_packet(rgep, slot)) != NULL) {
337 			*tail = mp;
338 			tail = &mp->b_next;
339 		}
340 
341 		/*
342 		 * Clear RBD flags
343 		 */
344 		hw_rbd_p->flags_len =
345 		    RGE_BSWAP_32(rgep->rxbuf_size - rgep->head_room);
346 		HW_RBD_INIT(hw_rbd_p, slot);
347 		slot = NEXT(slot, RGE_RECV_SLOTS);
348 		hw_rbd_p = &rgep->rx_ring[slot];
349 	}
350 
351 	rgep->rx_next = slot;
352 	return (head);
353 }
354 
355 /*
356  * Receive all ready packets.
357  */
358 void rge_receive(rge_t *rgep);
359 #pragma	no_inline(rge_receive)
360 
361 void
362 rge_receive(rge_t *rgep)
363 {
364 	mblk_t *mp;
365 
366 	mutex_enter(rgep->rx_lock);
367 	mp = rge_receive_ring(rgep);
368 	mutex_exit(rgep->rx_lock);
369 
370 	if (mp != NULL)
371 		mac_rx(rgep->mh, rgep->handle, mp);
372 }
373 
374 
375 #undef	RGE_DBG
376 #define	RGE_DBG		RGE_DBG_SEND	/* debug flag for this code	*/
377 
378 
379 /*
380  * ========== Send-side recycle routines ==========
381  */
382 static uint32_t rge_send_claim(rge_t *rgep);
383 #pragma	inline(rge_send_claim)
384 
385 static uint32_t
386 rge_send_claim(rge_t *rgep)
387 {
388 	uint32_t slot;
389 	uint32_t next;
390 
391 	mutex_enter(rgep->tx_lock);
392 	slot = rgep->tx_next;
393 	next = NEXT(slot, RGE_SEND_SLOTS);
394 	rgep->tx_next = next;
395 	rgep->tx_flow++;
396 	mutex_exit(rgep->tx_lock);
397 
398 	/*
399 	 * We check that our invariants still hold:
400 	 * +	the slot and next indexes are in range
401 	 * +	the slot must not be the last one (i.e. the *next*
402 	 *	index must not match the next-recycle index), 'cos
403 	 *	there must always be at least one free slot in a ring
404 	 */
405 	ASSERT(slot < RGE_SEND_SLOTS);
406 	ASSERT(next < RGE_SEND_SLOTS);
407 	ASSERT(next != rgep->tc_next);
408 
409 	return (slot);
410 }
411 
412 /*
413  * We don't want to call this function every time after a successful
414  * h/w transmit done in ISR.  Instead, we call this function in the
415  * rge_send() when there're few or no free tx BDs remained.
416  */
417 static void rge_send_recycle(rge_t *rgep);
418 #pragma	inline(rge_send_recycle)
419 
420 static void
421 rge_send_recycle(rge_t *rgep)
422 {
423 	rge_bd_t *hw_sbd_p;
424 	uint32_t tc_tail;
425 	uint32_t tc_head;
426 	uint32_t n;
427 
428 	mutex_enter(rgep->tc_lock);
429 	tc_head = rgep->tc_next;
430 	tc_tail = rgep->tc_tail;
431 	if (tc_head == tc_tail)
432 		goto resched;
433 
434 	do {
435 		tc_tail = LAST(tc_tail, RGE_SEND_SLOTS);
436 		hw_sbd_p = &rgep->tx_ring[tc_tail];
437 		if (tc_tail == tc_head) {
438 			if (hw_sbd_p->flags_len &
439 			    RGE_BSWAP_32(BD_FLAG_HW_OWN)) {
440 				/*
441 				 * Recyled nothing: bump the watchdog counter,
442 				 * thus guaranteeing that it's nonzero
443 				 * (watchdog activated).
444 				 */
445 				rgep->watchdog += 1;
446 				mutex_exit(rgep->tc_lock);
447 				return;
448 			}
449 			break;
450 		}
451 	} while (hw_sbd_p->flags_len & RGE_BSWAP_32(BD_FLAG_HW_OWN));
452 
453 	/*
454 	 * Recyled something :-)
455 	 */
456 	rgep->tc_next = NEXT(tc_tail, RGE_SEND_SLOTS);
457 	n = rgep->tc_next - tc_head;
458 	if (rgep->tc_next < tc_head)
459 		n += RGE_SEND_SLOTS;
460 	rge_atomic_renounce(&rgep->tx_free, n);
461 	rgep->watchdog = 0;
462 	ASSERT(rgep->tx_free <= RGE_SEND_SLOTS);
463 
464 resched:
465 	mutex_exit(rgep->tc_lock);
466 	if (rgep->resched_needed &&
467 	    rgep->rge_mac_state == RGE_MAC_STARTED) {
468 		rgep->resched_needed = B_FALSE;
469 		mac_tx_update(rgep->mh);
470 	}
471 }
472 
473 /*
474  * Send a message by copying it into a preallocated (and premapped) buffer
475  */
476 static void rge_send_copy(rge_t *rgep, mblk_t *mp, uint16_t tci);
477 #pragma	inline(rge_send_copy)
478 
479 static void
480 rge_send_copy(rge_t *rgep, mblk_t *mp, uint16_t tci)
481 {
482 	rge_bd_t *hw_sbd_p;
483 	sw_sbd_t *ssbdp;
484 	mblk_t *bp;
485 	char *txb;
486 	uint32_t slot;
487 	size_t totlen;
488 	size_t mblen;
489 	uint32_t pflags;
490 	struct ether_header *ethhdr;
491 	struct ip *ip_hdr;
492 
493 	/*
494 	 * IMPORTANT:
495 	 *	Up to the point where it claims a place, a send_msg()
496 	 *	routine can indicate failure by returning B_FALSE.  Once it's
497 	 *	claimed a place, it mustn't fail.
498 	 *
499 	 * In this version, there's no setup to be done here, and there's
500 	 * nothing that can fail, so we can go straight to claiming our
501 	 * already-reserved place on the train.
502 	 *
503 	 * This is the point of no return!
504 	 */
505 	slot = rge_send_claim(rgep);
506 	ssbdp = &rgep->sw_sbds[slot];
507 
508 	/*
509 	 * Copy the data into a pre-mapped buffer, which avoids the
510 	 * overhead (and complication) of mapping/unmapping STREAMS
511 	 * buffers and keeping hold of them until the DMA has completed.
512 	 *
513 	 * Because all buffers are the same size, and larger than the
514 	 * longest single valid message, we don't have to bother about
515 	 * splitting the message across multiple buffers either.
516 	 */
517 	txb = DMA_VPTR(ssbdp->pbuf);
518 	totlen = 0;
519 	bp = mp;
520 	if (tci != 0) {
521 		/*
522 		 * Do not copy the vlan tag
523 		 */
524 		bcopy(bp->b_rptr, txb, 2 * ETHERADDRL);
525 		txb += 2 * ETHERADDRL;
526 		totlen += 2 * ETHERADDRL;
527 		mblen = bp->b_wptr - bp->b_rptr;
528 		ASSERT(mblen >= 2 * ETHERADDRL + VLAN_TAGSZ);
529 		mblen -= 2 * ETHERADDRL + VLAN_TAGSZ;
530 		if ((totlen += mblen) <= rgep->ethmax_size) {
531 			bcopy(bp->b_rptr + 2 * ETHERADDRL + VLAN_TAGSZ,
532 			    txb, mblen);
533 			txb += mblen;
534 		}
535 		bp = bp->b_cont;
536 		rgep->stats.obytes += VLAN_TAGSZ;
537 	}
538 	for (; bp != NULL; bp = bp->b_cont) {
539 		mblen = bp->b_wptr - bp->b_rptr;
540 		if ((totlen += mblen) <= rgep->ethmax_size) {
541 			bcopy(bp->b_rptr, txb, mblen);
542 			txb += mblen;
543 		}
544 	}
545 	rgep->stats.obytes += totlen;
546 
547 	/*
548 	 * We'e reached the end of the chain; and we should have
549 	 * collected no more than ETHERMAX bytes into our buffer.
550 	 */
551 	ASSERT(bp == NULL);
552 	ASSERT(totlen <= rgep->ethmax_size);
553 	DMA_SYNC(ssbdp->pbuf, DDI_DMA_SYNC_FORDEV);
554 
555 	/*
556 	 * Update the hardware send buffer descriptor flags
557 	 */
558 	hw_sbd_p = &rgep->tx_ring[slot];
559 	ASSERT(hw_sbd_p == ssbdp->desc.mem_va);
560 	hw_sbd_p->flags_len = RGE_BSWAP_32(totlen & SBD_LEN_MASK);
561 	if (tci != 0) {
562 		tci = TCI_OS2CHIP(tci);
563 		hw_sbd_p->vlan_tag = RGE_BSWAP_32(tci);
564 		hw_sbd_p->vlan_tag |= RGE_BSWAP_32(SBD_VLAN_PKT);
565 	} else {
566 		hw_sbd_p->vlan_tag = 0;
567 	}
568 
569 	/*
570 	 * h/w checksum offload flags
571 	 */
572 	hcksum_retrieve(mp, NULL, NULL, NULL, NULL, NULL, NULL, &pflags);
573 	if (pflags & HCK_FULLCKSUM) {
574 		ASSERT(totlen >= sizeof (struct ether_header) +
575 		    sizeof (struct ip));
576 		ethhdr = (struct ether_header *)(DMA_VPTR(ssbdp->pbuf));
577 		/*
578 		 * Is the packet an IP(v4) packet?
579 		 */
580 		if (ntohs(ethhdr->ether_type) == ETHERTYPE_IP) {
581 			ip_hdr = (struct ip *)
582 			    ((uint8_t *)DMA_VPTR(ssbdp->pbuf) +
583 			    sizeof (struct ether_header));
584 			if (ip_hdr->ip_p == IPPROTO_TCP)
585 				hw_sbd_p->flags_len |=
586 				    RGE_BSWAP_32(SBD_FLAG_TCP_CKSUM);
587 			else if (ip_hdr->ip_p == IPPROTO_UDP)
588 				hw_sbd_p->flags_len |=
589 				    RGE_BSWAP_32(SBD_FLAG_UDP_CKSUM);
590 		}
591 	}
592 	if (pflags & HCK_IPV4_HDRCKSUM)
593 		hw_sbd_p->flags_len |= RGE_BSWAP_32(SBD_FLAG_IP_CKSUM);
594 
595 	HW_SBD_SET(hw_sbd_p, slot);
596 
597 	/*
598 	 * We're done.
599 	 * The message can be freed right away, as we've already
600 	 * copied the contents ...
601 	 */
602 	freemsg(mp);
603 }
604 
605 static boolean_t
606 rge_send(rge_t *rgep, mblk_t *mp)
607 {
608 	struct ether_vlan_header *ehp;
609 	uint16_t tci;
610 
611 	ASSERT(mp->b_next == NULL);
612 
613 	/*
614 	 * Try to reserve a place in the transmit ring.
615 	 */
616 	if (!rge_atomic_reserve(&rgep->tx_free, 1)) {
617 		RGE_DEBUG(("rge_send: no free slots"));
618 		rgep->stats.defer++;
619 		rgep->resched_needed = B_TRUE;
620 		(void) ddi_intr_trigger_softint(rgep->resched_hdl, NULL);
621 		return (B_FALSE);
622 	}
623 
624 	/*
625 	 * Determine if the packet is VLAN tagged.
626 	 */
627 	ASSERT(MBLKL(mp) >= sizeof (struct ether_header));
628 	tci = 0;
629 	ehp = (struct ether_vlan_header *)mp->b_rptr;
630 	if (ehp->ether_tpid == htons(ETHERTYPE_VLAN))
631 		tci = ntohs(ehp->ether_tci);
632 
633 	/*
634 	 * We've reserved a place :-)
635 	 * These ASSERTions check that our invariants still hold:
636 	 *	there must still be at least one free place
637 	 *	there must be at least one place NOT free (ours!)
638 	 */
639 	ASSERT(rgep->tx_free < RGE_SEND_SLOTS);
640 	rge_send_copy(rgep, mp, tci);
641 
642 	/*
643 	 * Trigger chip h/w transmit ...
644 	 */
645 	mutex_enter(rgep->tx_lock);
646 	if (--rgep->tx_flow == 0) {
647 		DMA_SYNC(rgep->tx_desc, DDI_DMA_SYNC_FORDEV);
648 		rge_tx_trigger(rgep);
649 		if (rgep->tx_free < RGE_SEND_SLOTS/2)
650 			rge_send_recycle(rgep);
651 		rgep->tc_tail = rgep->tx_next;
652 	}
653 	mutex_exit(rgep->tx_lock);
654 
655 	return (B_TRUE);
656 }
657 
658 uint_t
659 rge_reschedule(caddr_t arg1, caddr_t arg2)
660 {
661 	rge_t *rgep;
662 
663 	rgep = (rge_t *)arg1;
664 	_NOTE(ARGUNUSED(arg2))
665 
666 	rge_send_recycle(rgep);
667 
668 	return (DDI_INTR_CLAIMED);
669 }
670 
671 /*
672  * rge_m_tx() - send a chain of packets
673  */
674 mblk_t *
675 rge_m_tx(void *arg, mblk_t *mp)
676 {
677 	rge_t *rgep = arg;		/* private device info	*/
678 	mblk_t *next;
679 
680 	ASSERT(mp != NULL);
681 	ASSERT(rgep->rge_mac_state == RGE_MAC_STARTED);
682 
683 	if (rgep->rge_chip_state != RGE_CHIP_RUNNING) {
684 		RGE_DEBUG(("rge_m_tx: chip not running"));
685 		return (mp);
686 	}
687 
688 	rw_enter(rgep->errlock, RW_READER);
689 	while (mp != NULL) {
690 		next = mp->b_next;
691 		mp->b_next = NULL;
692 
693 		if (!rge_send(rgep, mp)) {
694 			mp->b_next = next;
695 			break;
696 		}
697 
698 		mp = next;
699 	}
700 	rw_exit(rgep->errlock);
701 
702 	return (mp);
703 }
704