xref: /netbsd-src/sys/arch/mac68k/dev/if_ae.c (revision 6ea46cb5e46c49111a6ecf3bcbe3c7e2730fe9f6)
1 /*
2  * Device driver for National Semiconductor DS8390 based ethernet adapters.
3  *
4  * Based on original ISA bus driver by David Greenman, 29-April-1993
5  *
6  * Copyright (C) 1993, David Greenman. This software may be used, modified,
7  *   copied, distributed, and sold, in both source and binary form provided
8  *   that the above copyright and these terms are retained. Under no
9  *   circumstances is the author responsible for the proper functioning
10  *   of this software, nor does the author assume any responsibility
11  *   for damages incurred with its use.
12  *
13  * Adapted for MacBSD by Brad Parker <brad@fcr.com>
14  *
15  * Currently supports:
16  *	Apples NB Ethernet card
17  *	Interlan A310 Nubus Ethernet card
18  *	Cayman Systems GatorCard
19  */
20 
21 /*
22  * $Id: if_ae.c,v 1.13 1994/06/26 13:01:24 briggs Exp $
23  */
24 
25 #include "ae.h"
26 /* bpfilter included here in case it is needed in future net includes */
27 #include "bpfilter.h"
28 
29 #include <sys/param.h>
30 #include <sys/systm.h>
31 #include <sys/errno.h>
32 #include <sys/ioctl.h>
33 #include <sys/mbuf.h>
34 #include <sys/socket.h>
35 #include <sys/syslog.h>
36 
37 #include <net/if.h>
38 #include <net/if_dl.h>
39 #include <net/if_types.h>
40 #include <net/netisr.h>
41 
42 #ifdef INET
43 #include <netinet/in.h>
44 #include <netinet/in_systm.h>
45 #include <netinet/in_var.h>
46 #include <netinet/ip.h>
47 #include <netinet/if_ether.h>
48 #endif
49 
50 #ifdef NS
51 #include <netns/ns.h>
52 #include <netns/ns_if.h>
53 #endif
54 
55 #if NBPFILTER > 0
56 #include <net/bpf.h>
57 #include <net/bpfdesc.h>
58 #endif
59 
60 #include <sys/device.h>
61 #include "nubus.h"
62 #include "if_aereg.h"
63 
64 struct ae_device {
65 	struct device	ae_dev;
66 /*	struct nubusdev	ae_nu;
67 	struct intrhand	ae_ih;	*/
68 };
69 
70 /*
71  * ae_softc: per line info and status
72  */
73 struct	ae_softc {
74 	struct ae_device	*sc_ae;
75 
76 	struct	arpcom arpcom;	/* ethernet common */
77 
78 	char	*type_str;	/* pointer to type string */
79 	u_char	vendor;		/* interface vendor */
80 	u_char	type;		/* interface type code */
81 #define	APPLE_CARD(sc)		((sc)->vendor == AE_VENDOR_APPLE)
82 #define	REG_MAP(sc, reg)	(APPLE_CARD(sc) ? (0x0f-(reg))<<2 : (reg)<<2)
83 #define NIC_GET(sc, reg)	((sc)->nic_addr[REG_MAP(sc, reg)])
84 #define NIC_PUT(sc, reg, val)	((sc)->nic_addr[REG_MAP(sc, reg)] = (val))
85 	volatile caddr_t nic_addr; /* NIC (DS8390) I/O bus address */
86 	caddr_t	rom_addr;	/* on board prom address */
87 	caddr_t	smem_start;	/* shared memory start address */
88 	caddr_t	smem_end;	/* shared memory end address */
89 	u_long	smem_size;	/* total shared memory size */
90 	caddr_t	smem_ring;	/* start of RX ring-buffer (in smem) */
91 
92 	caddr_t	bpf;		/* BPF "magic cookie" */
93 
94 	u_char	xmit_busy;	/* transmitter is busy */
95 	u_char	txb_cnt;	/* Number of transmit buffers */
96 	u_char	txb_next;	/* Pointer to next buffer ready to xmit */
97 	u_short	txb_next_len;	/* next xmit buffer length */
98 	u_char	data_buffered;	/* data has been buffered in interface memory */
99 	u_char	tx_page_start;	/* first page of TX buffer area */
100 
101 	u_char	rec_page_start;	/* first page of RX ring-buffer */
102 	u_char	rec_page_stop;	/* last page of RX ring-buffer */
103 	u_char	next_packet;	/* pointer to next unread RX packet */
104 } ae_softc[NAE];
105 
106 void	ae_find(), ae_attach();
107 int	ae_init(), aeintr(), ae_ioctl(), ae_probe(),
108 	ae_start(), ae_reset(), ae_watchdog();
109 
110 struct cfdriver aecd =
111 { NULL, "ae", ae_probe, ae_attach, DV_IFNET, sizeof(struct ae_device), NULL, 0 };
112 
113 static void ae_stop();
114 static inline void ae_rint();
115 static inline void ae_xmit();
116 static inline char *ae_ring_copy();
117 
118 extern int ether_output();
119 
120 #define	ETHER_MIN_LEN	64
121 #define ETHER_MAX_LEN	1518
122 #define	ETHER_ADDR_LEN	6
123 #define	ETHER_HDR_SIZE	14
124 
125 char ae_name[] = "8390 Nubus Ethernet card";
126 static char zero = 0;
127 static u_char ones = 0xff;
128 
129 struct vendor_S {
130 	char	*manu;
131 	int	len;
132 	int	vendor;
133 } vend[] = {
134 	{ "Apple", 5, AE_VENDOR_APPLE },
135 	{ "3Com",  4, AE_VENDOR_APPLE },
136 	{ "Dayna", 5, AE_VENDOR_DAYNA },
137 	{ "Inter", 5, AE_VENDOR_INTERLAN },
138 };
139 
140 static int numvend = sizeof(vend)/sizeof(vend[0]);
141 
142 /*
143  * XXX These two should be moved to locore, and maybe changed to use shorts
144  * instead of bytes.  The reason for these is that bcopy and bzero use longs,
145  * which the ethernet cards can't handle.
146  */
147 
148 void
149 bbzero (char *addr, int len)
150 {
151 	while (len--) {
152 		*addr++ = 0;
153 	}
154 }
155 
156 void
157 bbcopy (char *src, char *dest, int len)
158 {
159 	while (len--) {
160 		*dest++ = *src++;
161 	}
162 }
163 
164 void
165 ae_id_card(nu, sc)
166 	struct nubus_hw	*nu;
167 	struct ae_softc	*sc;
168 {
169 	int	i;
170 
171 	/*
172 	 * Try to determine what type of card this is...
173 	 */
174 	sc->vendor = AE_VENDOR_UNKNOWN;
175 	for (i=0 ; i<numvend ; i++) {
176 		if (!strncmp(nu->Slot.manufacturer, vend[i].manu, vend[i].len)) {
177 			sc->vendor = vend[i].vendor;
178 			break;
179 		}
180 	}
181 	sc->type_str = (char *) (nu->Slot.manufacturer);
182 
183 	/* see if it's an Interlan/GatorCard
184 	sc->rom_addr = nu->addr + GC_ROM_OFFSET;
185 	if (sc->rom_addr[0x18] == 0x0 &&
186 	    sc->rom_addr[0x1c] == 0x55) {
187 		sc->vendor = AE_VENDOR_INTERLAN;
188 	} */
189 }
190 
191 int
192 ae_probe(parent, cf, aux)
193 	struct cfdriver	*parent;
194 	struct cfdata	*cf;
195 	void		*aux;
196 {
197 	register struct nubus_hw *nu = (struct nubus_hw *) aux;
198 	struct ae_softc *sc = &ae_softc[cf->cf_unit];
199 	int i, memsize;
200 	int flags = 0;
201 
202 	if (nu->Slot.type != NUBUS_NETWORK)
203 		return 0;
204 
205 	ae_id_card(nu, sc);
206 
207 	switch (sc->vendor) {
208 	      case AE_VENDOR_INTERLAN:
209 		sc->nic_addr = nu->addr + GC_NIC_OFFSET;
210 		sc->rom_addr = nu->addr + GC_ROM_OFFSET;
211 		sc->smem_start = nu->addr + GC_DATA_OFFSET;
212 		memsize = 8192;
213 
214 		/* reset the NIC chip */
215 		*((caddr_t)nu->addr + GC_RESET_OFFSET) = (char)zero;
216 
217 		/* Get station address from on-board ROM */
218 		for (i = 0; i < ETHER_ADDR_LEN; ++i)
219 			sc->arpcom.ac_enaddr[i] = *(sc->rom_addr + i*4);
220 		break;
221 
222 	      case AE_VENDOR_APPLE:
223 		sc->nic_addr = nu->addr + AE_NIC_OFFSET;
224 		sc->rom_addr = nu->addr + AE_ROM_OFFSET;
225 		sc->smem_start = nu->addr + AE_DATA_OFFSET;
226 		memsize = 8192;
227 
228 		/* Get station address from on-board ROM */
229 		for (i = 0; i < ETHER_ADDR_LEN; ++i)
230 			sc->arpcom.ac_enaddr[i] = *(sc->rom_addr + i*2);
231 		break;
232 
233 	      case AE_VENDOR_DAYNA:
234 		printf("We think we are a Dayna card, but ");
235 		sc->nic_addr = nu->addr + DP_NIC_OFFSET;
236 		sc->rom_addr = nu->addr + DP_ROM_OFFSET;
237 		sc->smem_start = nu->addr + DP_DATA_OFFSET;
238 		memsize = 8192;
239 
240 		/* Get station address from on-board ROM */
241 		for (i = 0; i < ETHER_ADDR_LEN; ++i)
242 			sc->arpcom.ac_enaddr[i] = *(sc->rom_addr + i*2);
243 		printf("it is dangerous to continue.\n");
244 		return 0; /* Since we don't work yet... */
245 		break;
246 
247 	      default:
248 		return 0;
249 		break;
250 	}
251 
252 	/*
253 	 * allocate one xmit buffer if < 16k, two buffers otherwise
254 	 */
255 	if ((memsize < 16384) || (flags & AE_FLAGS_NO_DOUBLE_BUFFERING)) {
256 		sc->smem_ring = sc->smem_start + (AE_PAGE_SIZE * AE_TXBUF_SIZE);
257 		sc->txb_cnt = 1;
258 		sc->rec_page_start = AE_TXBUF_SIZE;
259 	} else {
260 		sc->smem_ring = sc->smem_start + (AE_PAGE_SIZE * AE_TXBUF_SIZE * 2);
261 		sc->txb_cnt = 2;
262 		sc->rec_page_start = AE_TXBUF_SIZE * 2;
263 	}
264 
265 	sc->smem_size = memsize;
266 	sc->smem_end = sc->smem_start + memsize;
267 	sc->rec_page_stop = memsize / AE_PAGE_SIZE;
268 	sc->tx_page_start = 0;
269 
270 	/*
271 	 * Now zero memory and verify that it is clear
272 	 */
273 	bbzero(sc->smem_start, memsize);
274 
275 	for (i = 0; i < memsize; ++i)
276 		if (sc->smem_start[i]) {
277 	        	printf(": failed to clear shared memory at %x\n",
278 			       sc->smem_start + i);
279 
280 			return(0);
281 		}
282 
283 #ifdef DEBUG_PRINT
284 	printf("nic_addr %x, rom_addr %x\n",
285 		sc->nic_addr, sc->rom_addr);
286 	printf("smem_size %d\n", sc->smem_size);
287 	printf("smem_start %x, smem_ring %x, smem_end %x\n",
288 		sc->smem_start, sc->smem_ring, sc->smem_end);
289 	printf("phys address %02x:%02x:%02x:%02x:%02x:%02x\n",
290 		sc->arpcom.ac_enaddr[0],
291 		sc->arpcom.ac_enaddr[1],
292 		sc->arpcom.ac_enaddr[2],
293 		sc->arpcom.ac_enaddr[3],
294 		sc->arpcom.ac_enaddr[4],
295 		sc->arpcom.ac_enaddr[5]);
296 #endif
297 
298 	return(1);
299 }
300 
301 /*
302  * Install interface into kernel networking data structures
303  */
304 void
305 ae_attach(parent, self, aux)
306 	struct cfdriver	*parent, *self;
307 	void		*aux;
308 {
309 	struct nubus_hw	*nu = aux;
310 	struct ae_device *ae = (struct ae_device *) self;
311 	struct ae_softc *sc = &ae_softc[ae->ae_dev.dv_unit];
312 	struct cfdata *cf = ae->ae_dev.dv_cfdata;
313 	struct ifnet *ifp = &sc->arpcom.ac_if;
314 	struct ifaddr *ifa;
315 	struct sockaddr_dl *sdl;
316 
317 	sc->sc_ae = ae;
318 
319 	/*
320 	 * Set interface to stopped condition (reset)
321 	 */
322 	ae_stop(sc);
323 
324 	/*
325 	 * Initialize ifnet structure
326 	 */
327 	ifp->if_unit = ae->ae_dev.dv_unit;
328 	ifp->if_name = aecd.cd_name;
329 	ifp->if_mtu = ETHERMTU;
330 	ifp->if_output = ether_output;
331 	ifp->if_start = ae_start;
332 	ifp->if_ioctl = ae_ioctl;
333 	ifp->if_reset = ae_reset;
334 	ifp->if_watchdog = ae_watchdog;
335 	ifp->if_flags = (IFF_BROADCAST | IFF_SIMPLEX | IFF_NOTRAILERS);
336 
337 #if 0
338 	/*
339 	 * Set default state for ALTPHYS flag (used to disable the transceiver
340 	 * for AUI operation), based on compile-time config option.
341 	 */
342 	if (cf->cf_flags & AE_FLAGS_DISABLE_TRANSCEIVER)
343 		ifp->if_flags |= IFF_ALTPHYS;
344 #endif
345 
346 	/*
347 	 * Attach the interface
348 	 */
349 	if_attach(ifp);
350 
351 	/*
352 	 * Search down the ifa address list looking for the AF_LINK type entry
353 	 */
354  	ifa = ifp->if_addrlist;
355 	while ((ifa != 0) && (ifa->ifa_addr != 0) &&
356 	    (ifa->ifa_addr->sa_family != AF_LINK))
357 		ifa = ifa->ifa_next;
358 	/*
359 	 * If we find an AF_LINK type entry we fill in the hardware address.
360 	 *	This is useful for netstat(1) to keep track of which interface
361 	 *	is which.
362 	 */
363 	if ((ifa != 0) && (ifa->ifa_addr != 0)) {
364 		/*
365 		 * Fill in the link-level address for this interface
366 		 */
367 		sdl = (struct sockaddr_dl *)ifa->ifa_addr;
368 		sdl->sdl_type = IFT_ETHER;
369 		sdl->sdl_alen = ETHER_ADDR_LEN;
370 		sdl->sdl_slen = 0;
371 		bbcopy(sc->arpcom.ac_enaddr, LLADDR(sdl), ETHER_ADDR_LEN);
372 	}
373 
374 	/*
375 	 * Print additional info when attached
376 	 */
377 	printf(": address %s, ", ether_sprintf(sc->arpcom.ac_enaddr));
378 
379 	if (sc->type_str && (*sc->type_str != 0))
380 		printf("type %s ", sc->type_str);
381 	else
382 		printf("type unknown (0x%x) ", sc->type);
383 
384 	printf("\n");
385 
386 	/*
387 	 * If BPF is in the kernel, call the attach for it
388 	 */
389 #if NBPFILTER > 0
390 	bpfattach(&sc->bpf, ifp, DLT_EN10MB, sizeof(struct ether_header));
391 #endif
392 }
393 
394 /*
395  * Reset interface.
396  */
397 int
398 ae_reset(sc)
399 	struct ae_softc *sc;
400 {
401 	int s;
402 
403 	s = splnet();
404 
405 	/*
406 	 * Stop interface and re-initialize.
407 	 */
408 	ae_stop(sc);
409 	ae_init(sc);
410 
411 	(void) splx(s);
412 }
413 
414 /*
415  * Take interface offline.
416  */
417 void
418 ae_stop(sc)
419 	struct ae_softc *sc;
420 {
421 	int n = 5000;
422 
423 	/*
424 	 * Stop everything on the interface, and select page 0 registers.
425 	 */
426 	NIC_PUT(sc, AE_P0_CR, AE_CR_RD2|AE_CR_STP);
427 
428 	/*
429 	 * Wait for interface to enter stopped state, but limit # of checks
430 	 *	to 'n' (about 5ms). It shouldn't even take 5us on modern
431 	 *	DS8390's, but just in case it's an old one.
432 	 */
433 	while (((NIC_GET(sc, AE_P0_ISR) & AE_ISR_RST) == 0) && --n);
434 }
435 
436 /*
437  * Device timeout/watchdog routine. Entered if the device neglects to
438  *	generate an interrupt after a transmit has been started on it.
439  */
440 int
441 ae_watchdog(unit)
442 	short unit;
443 {
444 	log(LOG_ERR, "ae%d: device timeout\n", unit);
445 {
446 struct ae_softc *sc = &ae_softc[unit];
447 printf("cr %x, isr %x\n", NIC_GET(sc, AE_P0_CR), NIC_GET(sc, AE_P0_ISR));
448 /* via_dump(); */
449 if (NIC_GET(sc, AE_P0_ISR)) {
450 	aeintr(0);
451 	return;
452 }
453 }
454 	ae_reset(unit);
455 }
456 
457 /*
458  * Initialize device.
459  */
460 ae_init(sc)
461 	struct ae_softc *sc;
462 {
463 	struct ifnet *ifp = &sc->arpcom.ac_if;
464 	int i, s;
465 	u_char	command;
466 
467 
468 	/* address not known */
469 	if (ifp->if_addrlist == (struct ifaddr *)0) return;
470 
471 	/*
472 	 * Initialize the NIC in the exact order outlined in the NS manual.
473 	 *	This init procedure is "mandatory"...don't change what or when
474 	 *	things happen.
475 	 */
476 	s = splnet();
477 
478 	/* reset transmitter flags */
479 	sc->data_buffered = 0;
480 	sc->xmit_busy = 0;
481 	sc->arpcom.ac_if.if_timer = 0;
482 
483 	sc->txb_next = 0;
484 
485 	/* This variable is used below - don't move this assignment */
486 	sc->next_packet = sc->rec_page_start + 1;
487 
488 #ifdef DEBUG_PRINT
489 	printf("page_start %d, page_stop %d, next %d\n",
490 		sc->rec_page_start, sc->rec_page_stop, sc->next_packet);
491 #endif
492 
493 	/*
494 	 * Set interface for page 0, Remote DMA complete, Stopped
495 	 */
496 	NIC_PUT(sc, AE_P0_CR, AE_CR_RD2|AE_CR_STP);
497 
498 	/*
499 	 * Set FIFO threshold to 4, No auto-init Remote DMA, Burst mode,
500 	 *	byte order=80x86, word-wide DMA xfers,
501 	 */
502 	NIC_PUT(sc, AE_P0_DCR, AE_DCR_FT1|AE_DCR_BMS|AE_DCR_WTS);
503 
504 	/*
505 	 * Clear Remote Byte Count Registers
506 	 */
507 	NIC_PUT(sc, AE_P0_RBCR0, zero);
508 	NIC_PUT(sc, AE_P0_RBCR1, zero);
509 
510 	/*
511 	 * Enable reception of broadcast packets
512 	 */
513 	NIC_PUT(sc, AE_P0_RCR, AE_RCR_AB);
514 
515 	/*
516 	 * Place NIC in internal loopback mode
517 	 */
518 	NIC_PUT(sc, AE_P0_TCR, AE_TCR_LB0);
519 
520 	/*
521 	 * Initialize transmit/receive (ring-buffer) Page Start
522 	 */
523 	NIC_PUT(sc, AE_P0_TPSR, sc->tx_page_start);
524 	NIC_PUT(sc, AE_P0_PSTART, sc->rec_page_start);
525 
526 	/*
527 	 * Initialize Receiver (ring-buffer) Page Stop and Boundry
528 	 */
529 	NIC_PUT(sc, AE_P0_PSTOP, sc->rec_page_stop);
530 	NIC_PUT(sc, AE_P0_BNRY, sc->rec_page_start);
531 
532 	/*
533 	 * Clear all interrupts. A '1' in each bit position clears the
534 	 *	corresponding flag.
535 	 */
536 	NIC_PUT(sc, AE_P0_ISR, ones);
537 
538 	/*
539 	 * Enable the following interrupts: receive/transmit complete,
540 	 *	receive/transmit error, and Receiver OverWrite.
541 	 *
542 	 * Counter overflow and Remote DMA complete are *not* enabled.
543 	 */
544 	NIC_PUT(sc, AE_P0_IMR,
545 		AE_IMR_PRXE|AE_IMR_PTXE|AE_IMR_RXEE|AE_IMR_TXEE|AE_IMR_OVWE);
546 
547 	/*
548 	 * Program Command Register for page 1
549 	 */
550 	NIC_PUT(sc, AE_P0_CR, AE_CR_PAGE_1|AE_CR_RD2|AE_CR_STP);
551 
552 	/*
553 	 * Copy out our station address
554 	 */
555 	for (i = 0; i < ETHER_ADDR_LEN; ++i)
556 		NIC_PUT(sc, AE_P1_PAR0 + i, sc->arpcom.ac_enaddr[i]);
557 
558 #if NBPFILTER > 0
559 	/*
560 	 * Initialize multicast address hashing registers to accept
561 	 *	 all multicasts (only used when in promiscuous mode)
562 	 */
563 	for (i = 0; i < 8; ++i)
564 		NIC_PUT(sc, AE_P1_MAR0 + i, 0xff);
565 #endif
566 
567 	/*
568 	 * Set Current Page pointer to next_packet (initialized above)
569 	 */
570 	NIC_PUT(sc, AE_P1_CURR, sc->next_packet);
571 
572 	/*
573 	 * Set Command Register for page 0, Remote DMA complete,
574 	 * 	and interface Start.
575 	 */
576 	NIC_PUT(sc, AE_P1_CR, AE_CR_RD2|AE_CR_STA);
577 
578 	/*
579 	 * Take interface out of loopback
580 	 */
581 	NIC_PUT(sc, AE_P0_TCR, zero);
582 
583 	/*
584 	 * Set 'running' flag, and clear output active flag.
585 	 */
586 	ifp->if_flags |= IFF_RUNNING;
587 	ifp->if_flags &= ~IFF_OACTIVE;
588 
589 	/* XXXXXX */
590 	add_nubus_intr((int)sc->rom_addr & 0xFF000000, aeintr, sc - ae_softc);
591 
592 	/*
593 	 * ...and attempt to start output
594 	 */
595 	ae_start(ifp);
596 
597 	(void) splx(s);
598 }
599 
600 /*
601  * This routine actually starts the transmission on the interface
602  */
603 static inline void ae_xmit(ifp)
604 	struct ifnet *ifp;
605 {
606 	struct ae_softc *sc = &ae_softc[ifp->if_unit];
607 	u_short len = sc->txb_next_len;
608 
609 	/*
610 	 * Set NIC for page 0 register access
611 	 */
612 	NIC_PUT(sc, AE_P0_CR, AE_CR_RD2|AE_CR_STA);
613 
614 	/*
615 	 * Set TX buffer start page
616 	 */
617 	NIC_PUT(sc, AE_P0_TPSR, sc->tx_page_start +
618 		sc->txb_next * AE_TXBUF_SIZE);
619 
620 	/*
621 	 * Set TX length
622 	 */
623 	NIC_PUT(sc, AE_P0_TBCR0, len & 0xff);
624 	NIC_PUT(sc, AE_P0_TBCR1, len >> 8);
625 
626 	/*
627 	 * Set page 0, Remote DMA complete, Transmit Packet, and *Start*
628 	 */
629 	NIC_PUT(sc, AE_P0_CR, AE_CR_RD2|AE_CR_TXP|AE_CR_STA);
630 
631 	sc->xmit_busy = 1;
632 	sc->data_buffered = 0;
633 
634 	/*
635 	 * Switch buffers if we are doing double-buffered transmits
636 	 */
637 	if ((sc->txb_next == 0) && (sc->txb_cnt > 1))
638 		sc->txb_next = 1;
639 	else
640 		sc->txb_next = 0;
641 
642 	/*
643 	 * Set a timer just in case we never hear from the board again
644 	 */
645 	ifp->if_timer = 2;
646 }
647 
648 /*
649  * Start output on interface.
650  * We make two assumptions here:
651  *  1) that the current priority is set to splnet _before_ this code
652  *     is called *and* is returned to the appropriate priority after
653  *     return
654  *  2) that the IFF_OACTIVE flag is checked before this code is called
655  *     (i.e. that the output part of the interface is idle)
656  */
657 int
658 ae_start(ifp)
659 	struct ifnet *ifp;
660 {
661 	struct ae_softc *sc = &ae_softc[ifp->if_unit];
662 	struct mbuf *m0, *m;
663 	caddr_t buffer;
664 	int len;
665 
666 outloop:
667 	/*
668 	 * See if there is room to send more data (i.e. one or both of the
669 	 *	buffers is empty).
670 	 */
671 	if (sc->data_buffered)
672 		if (sc->xmit_busy) {
673 			/*
674 			 * No room. Indicate this to the outside world
675 			 *	and exit.
676 			 */
677 			ifp->if_flags |= IFF_OACTIVE;
678 			return;
679 		} else {
680 			/*
681 			 * Data is buffered, but we're not transmitting, so
682 			 *	start the xmit on the buffered data.
683 			 * Note that ae_xmit() resets the data_buffered flag
684 			 *	before returning.
685 			 */
686 			ae_xmit(ifp);
687 		}
688 
689 	IF_DEQUEUE(&sc->arpcom.ac_if.if_snd, m);
690 	if (m == 0) {
691 	/*
692 	 * The following isn't pretty; we are using the !OACTIVE flag to
693 	 * indicate to the outside world that we can accept an additional
694 	 * packet rather than that the transmitter is _actually_
695 	 * active. Indeed, the transmitter may be active, but if we haven't
696 	 * filled the secondary buffer with data then we still want to
697 	 * accept more.
698 	 * Note that it isn't necessary to test the data_buffered flag -
699 	 * we wouldn't have tried to de-queue the packet in the first place
700 	 * if it was set.
701 	 */
702 		ifp->if_flags &= ~IFF_OACTIVE;
703 		return;
704 	}
705 
706 	/*
707 	 * Copy the mbuf chain into the transmit buffer
708 	 */
709 	buffer = sc->smem_start + (sc->txb_next * AE_TXBUF_SIZE * AE_PAGE_SIZE);
710 	len = 0;
711 	for (m0 = m; m != 0; m = m->m_next) {
712 		/*printf("ae: copy %d bytes @ %x\n", m->m_len, buffer);*/
713 		bbcopy(mtod(m, caddr_t), buffer, m->m_len);
714 		buffer += m->m_len;
715        		len += m->m_len;
716 	}
717 if (len & 1) len++;
718 
719 	sc->txb_next_len = max(len, ETHER_MIN_LEN);
720 
721 	if (sc->txb_cnt > 1)
722 		/*
723 		 * only set 'buffered' flag if doing multiple buffers
724 		 */
725 		sc->data_buffered = 1;
726 
727 	if (sc->xmit_busy == 0)
728 		ae_xmit(ifp);
729 	/*
730 	 * If there is BPF support in the configuration, tap off here.
731 	 *   The following has support for converting trailer packets
732 	 *   back to normal.
733 	 */
734 #if NBPFILTER > 0
735 	if (sc->bpf) {
736 		u_short etype;
737 		int off, datasize, resid;
738 		struct ether_header *eh;
739 		struct trailer_header {
740 			u_short ether_type;
741 			u_short ether_residual;
742 		} trailer_header;
743 		char ether_packet[ETHER_MAX_LEN];
744 		char *ep;
745 
746 		ep = ether_packet;
747 
748 		/*
749 		 * We handle trailers below:
750 		 * Copy ether header first, then residual data,
751 		 * then data. Put all this in a temporary buffer
752 		 * 'ether_packet' and send off to bpf. Since the
753 		 * system has generated this packet, we assume
754 		 * that all of the offsets in the packet are
755 		 * correct; if they're not, the system will almost
756 		 * certainly crash in m_copydata.
757 		 * We make no assumptions about how the data is
758 		 * arranged in the mbuf chain (i.e. how much
759 		 * data is in each mbuf, if mbuf clusters are
760 		 * used, etc.), which is why we use m_copydata
761 		 * to get the ether header rather than assume
762 		 * that this is located in the first mbuf.
763 		 */
764 		/* copy ether header */
765 		m_copydata(m0, 0, sizeof(struct ether_header), ep);
766 		eh = (struct ether_header *) ep;
767 		ep += sizeof(struct ether_header);
768 		etype = ntohs(eh->ether_type);
769 		if (etype >= ETHERTYPE_TRAIL &&
770 		    etype < ETHERTYPE_TRAIL+ETHERTYPE_NTRAILER) {
771 			datasize = ((etype - ETHERTYPE_TRAIL) << 9);
772 			off = datasize + sizeof(struct ether_header);
773 
774 			/* copy trailer_header into a data structure */
775 			m_copydata(m0, off, sizeof(struct trailer_header),
776 				&trailer_header.ether_type);
777 
778 			/* copy residual data */
779 			m_copydata(m0, off+sizeof(struct trailer_header),
780 				resid = ntohs(trailer_header.ether_residual) -
781 				sizeof(struct trailer_header), ep);
782 			ep += resid;
783 
784 			/* copy data */
785 			m_copydata(m0, sizeof(struct ether_header),
786 				datasize, ep);
787 			ep += datasize;
788 
789 			/* restore original ether packet type */
790 			eh->ether_type = trailer_header.ether_type;
791 
792 			bpf_tap(sc->bpf, ether_packet, ep - ether_packet);
793 		} else
794 			bpf_mtap(sc->bpf, m0);
795 	}
796 #endif
797 
798 	m_freem(m0);
799 
800 	/*
801 	 * If we are doing double-buffering, a buffer might be free to
802 	 *	fill with another packet, so loop back to the top.
803 	 */
804 	if (sc->txb_cnt > 1)
805 		goto outloop;
806 	else {
807 		ifp->if_flags |= IFF_OACTIVE;
808 		return;
809 	}
810 }
811 
812 /*
813  * Ethernet interface receiver interrupt.
814  */
815 static inline void
816 ae_rint(unit)
817 	int unit;
818 {
819 	register struct ae_softc *sc = &ae_softc[unit];
820 	u_char boundry, current;
821 	u_short len;
822 	struct ae_ring *packet_ptr;
823 
824 	/*
825 	 * Set NIC to page 1 registers to get 'current' pointer
826 	 */
827 	NIC_PUT(sc, AE_P0_CR, AE_CR_PAGE_1|AE_CR_RD2|AE_CR_STA);
828 
829 	/*
830 	 * 'sc->next_packet' is the logical beginning of the ring-buffer - i.e.
831 	 *	it points to where new data has been buffered. The 'CURR'
832 	 *	(current) register points to the logical end of the ring-buffer
833 	 *	- i.e. it points to where additional new data will be added.
834 	 *	We loop here until the logical beginning equals the logical
835 	 *	end (or in other words, until the ring-buffer is empty).
836 	 */
837 	while (sc->next_packet != NIC_GET(sc, AE_P1_CURR)) {
838 
839 		/* get pointer to this buffer header structure */
840 		packet_ptr = (struct ae_ring *)(sc->smem_ring +
841 			 (sc->next_packet - sc->rec_page_start) * AE_PAGE_SIZE);
842 
843 		/*
844 		 * The byte count includes the FCS - Frame Check Sequence (a
845 		 *	32 bit CRC).
846 		 */
847 		len = packet_ptr->count[0] | (packet_ptr->count[1] << 8);
848 		if ((len >= ETHER_MIN_LEN) && (len <= ETHER_MAX_LEN)) {
849 			/*
850 			 * Go get packet. len - 4 removes CRC from length.
851 			 * (packet_ptr + 1) points to data just after the packet ring
852 			 *	header (+4 bytes)
853 			 */
854 			ae_get_packet(sc, (caddr_t)(packet_ptr + 1), len - 4);
855 			++sc->arpcom.ac_if.if_ipackets;
856 		} else {
857 			/*
858 			 * Really BAD...probably indicates that the ring pointers
859 			 *	are corrupted. Also seen on early rev chips under
860 			 *	high load - the byte order of the length gets switched.
861 			 */
862 			log(LOG_ERR,
863 				"ae%d: shared memory corrupt - invalid packet length %d\n",
864 				unit, len);
865 			ae_reset(unit);
866 			return;
867 		}
868 
869 		/*
870 		 * Update next packet pointer
871 		 */
872 		sc->next_packet = packet_ptr->next_packet;
873 
874 		/*
875 		 * Update NIC boundry pointer - being careful to keep it
876 		 *	one buffer behind. (as recommended by NS databook)
877 		 */
878 		boundry = sc->next_packet - 1;
879 		if (boundry < sc->rec_page_start)
880 			boundry = sc->rec_page_stop - 1;
881 
882 		/*
883 		 * Set NIC to page 0 registers to update boundry register
884 		 */
885 		NIC_PUT(sc, AE_P0_CR, AE_CR_RD2|AE_CR_STA);
886 
887 		NIC_PUT(sc, AE_P0_BNRY, boundry);
888 
889 		/*
890 		 * Set NIC to page 1 registers before looping to top (prepare to
891 		 *	get 'CURR' current pointer)
892 		 */
893 		NIC_PUT(sc, AE_P0_CR, AE_CR_PAGE_1|AE_CR_RD2|AE_CR_STA);
894 	}
895 }
896 
897 /*
898  * Ethernet interface interrupt processor
899  */
900 int
901 aeintr(unit)
902 	int unit;
903 {
904 	struct ae_softc *sc = &ae_softc[unit];
905 	u_char isr;
906 
907 	/*
908 	 * Set NIC to page 0 registers
909 	 */
910 	NIC_PUT(sc, AE_P0_CR, AE_CR_RD2|AE_CR_STA);
911 
912 	/*
913 	 * loop until there are no more new interrupts
914 	 */
915 	while (isr = NIC_GET(sc, AE_P0_ISR)) {
916 
917 		/*
918 		 * reset all the bits that we are 'acknowledging'
919 		 *	by writing a '1' to each bit position that was set
920 		 * (writing a '1' *clears* the bit)
921 		 */
922 		NIC_PUT(sc, AE_P0_ISR, isr);
923 
924 		/*
925 		 * Handle transmitter interrupts. Handle these first
926 		 *	because the receiver will reset the board under
927 		 *	some conditions.
928 		 */
929 		if (isr & (AE_ISR_PTX|AE_ISR_TXE)) {
930 			u_char collisions = NIC_GET(sc, AE_P0_NCR);
931 
932 			/*
933 			 * Check for transmit error. If a TX completed with an
934 			 * error, we end up throwing the packet away. Really
935 			 * the only error that is possible is excessive
936 			 * collisions, and in this case it is best to allow the
937 			 * automatic mechanisms of TCP to backoff the flow. Of
938 			 * course, with UDP we're screwed, but this is expected
939 			 * when a network is heavily loaded.
940 			 */
941 			if (isr & AE_ISR_TXE) {
942 
943 				/*
944 				 * Excessive collisions (16)
945 				 */
946 				if ((NIC_GET(sc, AE_P0_TSR) & AE_TSR_ABT)
947 					&& (collisions == 0)) {
948 					/*
949 					 *    When collisions total 16, the
950 					 * P0_NCR will indicate 0, and the
951 					 * TSR_ABT is set.
952 					 */
953 					collisions = 16;
954 				}
955 
956 				/*
957 				 * update output errors counter
958 				 */
959 				++sc->arpcom.ac_if.if_oerrors;
960 			} else {
961 				/*
962 				 * Update total number of successfully
963 				 * 	transmitted packets.
964 				 */
965 				++sc->arpcom.ac_if.if_opackets;
966 			}
967 
968 			/*
969 			 * reset tx busy and output active flags
970 			 */
971 			sc->xmit_busy = 0;
972 			sc->arpcom.ac_if.if_flags &= ~IFF_OACTIVE;
973 
974 			/*
975 			 * clear watchdog timer
976 			 */
977 			sc->arpcom.ac_if.if_timer = 0;
978 
979 			/*
980 			 * Add in total number of collisions on last
981 			 *	transmission.
982 			 */
983 			sc->arpcom.ac_if.if_collisions += collisions;
984 
985 			/*
986 			 * If data is ready to transmit, start it transmitting,
987 			 *	otherwise defer until after handling receiver
988 			 */
989 			if (sc->data_buffered)
990 				ae_xmit(&sc->arpcom.ac_if);
991 		}
992 
993 		/*
994 		 * Handle receiver interrupts
995 		 */
996 		if (isr & (AE_ISR_PRX|AE_ISR_RXE|AE_ISR_OVW)) {
997 		    /*
998 		     * Overwrite warning. In order to make sure that a lockup
999 		     *	of the local DMA hasn't occurred, we reset and
1000 		     *	re-init the NIC. The NSC manual suggests only a
1001 		     *	partial reset/re-init is necessary - but some
1002 		     *	chips seem to want more. The DMA lockup has been
1003 		     *	seen only with early rev chips - Methinks this
1004 		     *	bug was fixed in later revs. -DG
1005 		     */
1006 			if (isr & AE_ISR_OVW) {
1007 				++sc->arpcom.ac_if.if_ierrors;
1008 				log(LOG_WARNING,
1009 					"ae%d: warning - receiver ring buffer overrun\n",
1010 					unit);
1011 				/*
1012 				 * Stop/reset/re-init NIC
1013 				 */
1014 				ae_reset(unit);
1015 			} else {
1016 
1017 			    /*
1018 			     * Receiver Error. One or more of: CRC error, frame
1019 			     *	alignment error FIFO overrun, or missed packet.
1020 			     */
1021 				if (isr & AE_ISR_RXE) {
1022 					++sc->arpcom.ac_if.if_ierrors;
1023 #ifdef AE_DEBUG
1024 					printf("ae%d: receive error %x\n", unit,
1025 						NIC_GET(sc, AE_P0_RSR));
1026 #endif
1027 				}
1028 
1029 				/*
1030 				 * Go get the packet(s)
1031 				 * XXX - Doing this on an error is dubious
1032 				 *    because there shouldn't be any data to
1033 				 *    get (we've configured the interface to
1034 				 *    not accept packets with errors).
1035 				 */
1036 				ae_rint (unit);
1037 			}
1038 		}
1039 
1040 		/*
1041 		 * If it looks like the transmitter can take more data,
1042 		 * 	attempt to start output on the interface.
1043 		 *	This is done after handling the receiver to
1044 		 *	give the receiver priority.
1045 		 */
1046 		if ((sc->arpcom.ac_if.if_flags & IFF_OACTIVE) == 0)
1047 			ae_start(&sc->arpcom.ac_if);
1048 
1049 		/*
1050 		 * return NIC CR to standard state: page 0, remote DMA complete,
1051 		 * 	start (toggling the TXP bit off, even if was just set
1052 		 *	in the transmit routine, is *okay* - it is 'edge'
1053 		 *	triggered from low to high)
1054 		 */
1055 		NIC_PUT(sc, AE_P0_CR, AE_CR_RD2|AE_CR_STA);
1056 
1057 		/*
1058 		 * If the Network Talley Counters overflow, read them to
1059 		 *	reset them. It appears that old 8390's won't
1060 		 *	clear the ISR flag otherwise - resulting in an
1061 		 *	infinite loop.
1062 		 */
1063 		if (isr & AE_ISR_CNT) {
1064 			(void) NIC_GET(sc, AE_P0_CNTR0);
1065 			(void) NIC_GET(sc, AE_P0_CNTR1);
1066 			(void) NIC_GET(sc, AE_P0_CNTR2);
1067 		}
1068 	}
1069 }
1070 
1071 /*
1072  * Process an ioctl request. This code needs some work - it looks
1073  *	pretty ugly.
1074  */
1075 int
1076 ae_ioctl(ifp, command, data)
1077 	register struct ifnet *ifp;
1078 	int command;
1079 	caddr_t data;
1080 {
1081 	register struct ifaddr *ifa = (struct ifaddr *)data;
1082 	struct ae_softc *sc = &ae_softc[ifp->if_unit];
1083 	struct ifreq *ifr = (struct ifreq *)data;
1084 	int s, error = 0;
1085 
1086 	s = splnet();
1087 
1088 	switch (command) {
1089 
1090 	case SIOCSIFADDR:
1091 		ifp->if_flags |= IFF_UP;
1092 
1093 		switch (ifa->ifa_addr->sa_family) {
1094 #ifdef INET
1095 		case AF_INET:
1096 			ae_init(sc);	/* before arpwhohas */
1097 			/*
1098 			 * See if another station has *our* IP address.
1099 			 * i.e.: There is an address conflict! If a
1100 			 * conflict exists, a message is sent to the
1101 			 * console.
1102 			 */
1103 			((struct arpcom *)ifp)->ac_ipaddr =
1104 				IA_SIN(ifa)->sin_addr;
1105 			arpwhohas((struct arpcom *)ifp, &IA_SIN(ifa)->sin_addr);
1106 			break;
1107 #endif
1108 #ifdef NS
1109 		/*
1110 		 * XXX - This code is probably wrong
1111 		 */
1112 		case AF_NS:
1113 		    {
1114 			register struct ns_addr *ina = &(IA_SNS(ifa)->sns_addr);
1115 
1116 			if (ns_nullhost(*ina))
1117 				ina->x_host =
1118 					*(union ns_host *)(sc->arpcom.ac_enaddr);
1119 			else {
1120 				/*
1121 				 *
1122 				 */
1123 				bbcopy((caddr_t)ina->x_host.c_host,
1124 				    (caddr_t)sc->arpcom.ac_enaddr,
1125 					sizeof(sc->arpcom.ac_enaddr));
1126 			}
1127 			/*
1128 			 * Set new address
1129 			 */
1130 			ae_init(sc);
1131 			break;
1132 		    }
1133 #endif
1134 		default:
1135 			ae_init(sc);
1136 			break;
1137 		}
1138 		break;
1139 
1140 	case SIOCSIFFLAGS:
1141 		/*
1142 		 * If interface is marked down and it is running, then stop it
1143 		 */
1144 		if (((ifp->if_flags & IFF_UP) == 0) &&
1145 		    (ifp->if_flags & IFF_RUNNING)) {
1146 			ae_stop(ifp->if_unit);
1147 			ifp->if_flags &= ~IFF_RUNNING;
1148 		} else {
1149 		/*
1150 		 * If interface is marked up and it is stopped, then start it
1151 		 */
1152 			if ((ifp->if_flags & IFF_UP) &&
1153 		    	    ((ifp->if_flags & IFF_RUNNING) == 0))
1154 				ae_init(sc);
1155 		}
1156 #if NBPFILTER > 0
1157 		if (ifp->if_flags & IFF_PROMISC) {
1158 			/*
1159 			 * Set promiscuous mode on interface.
1160 			 *	XXX - for multicasts to work, we would need to
1161 			 *		write 1's in all bits of multicast
1162 			 *		hashing array. For now we assume that
1163 			 *		this was done in ae_init().
1164 			 */
1165 			NIC_PUT(sc, AE_P0_RCR,
1166 				AE_RCR_PRO|AE_RCR_AM|AE_RCR_AB);
1167 		} else {
1168 			/*
1169 			 * XXX - for multicasts to work, we would need to
1170 			 *	rewrite the multicast hashing array with the
1171 			 *	proper hash (would have been destroyed above).
1172 			 */
1173 			NIC_PUT(sc, AE_P0_RCR, AE_RCR_AB);
1174 		}
1175 #endif
1176 		break;
1177 
1178 	default:
1179 		error = EINVAL;
1180 	}
1181 	(void) splx(s);
1182 	return (error);
1183 }
1184 
1185 /*
1186  * Macro to calculate a new address within shared memory when given an offset
1187  *	from an address, taking into account ring-wrap.
1188  */
1189 #define	ringoffset(sc, start, off, type) \
1190 	((type)( ((caddr_t)(start)+(off) >= (sc)->smem_end) ? \
1191 		(((caddr_t)(start)+(off))) - (sc)->smem_end \
1192 		+ (sc)->smem_ring: \
1193 		((caddr_t)(start)+(off)) ))
1194 
1195 /*
1196  * Retreive packet from shared memory and send to the next level up via
1197  *	ether_input(). If there is a BPF listener, give a copy to BPF, too.
1198  */
1199 ae_get_packet(sc, buf, len)
1200 	struct ae_softc *sc;
1201 	char *buf;
1202 	u_short len;
1203 {
1204 	struct ether_header *eh;
1205     	struct mbuf *m, *head, *ae_ring_to_mbuf();
1206 	u_short off;
1207 	int resid;
1208 	u_short etype;
1209 	struct trailer_header {
1210 		u_short	trail_type;
1211 		u_short trail_residual;
1212 	} trailer_header;
1213 
1214 	/* Allocate a header mbuf */
1215 	MGETHDR(m, M_DONTWAIT, MT_DATA);
1216 	if (m == 0)
1217 		goto bad;
1218 	m->m_pkthdr.rcvif = &sc->arpcom.ac_if;
1219 	m->m_pkthdr.len = len;
1220 	m->m_len = 0;
1221 	head = m;
1222 
1223 	eh = (struct ether_header *)buf;
1224 
1225 	/* The following sillines is to make NFS happy */
1226 #define EROUND	((sizeof(struct ether_header) + 3) & ~3)
1227 #define EOFF	(EROUND - sizeof(struct ether_header))
1228 
1229 	/*
1230 	 * The following assumes there is room for
1231 	 * the ether header in the header mbuf
1232 	 */
1233 	head->m_data += EOFF;
1234 	bbcopy(buf, mtod(head, caddr_t), sizeof(struct ether_header));
1235 	buf += sizeof(struct ether_header);
1236 	head->m_len += sizeof(struct ether_header);
1237 	len -= sizeof(struct ether_header);
1238 
1239 	etype = ntohs((u_short)eh->ether_type);
1240 
1241 	/*
1242 	 * Deal with trailer protocol:
1243 	 * If trailer protocol, calculate the datasize as 'off',
1244 	 * which is also the offset to the trailer header.
1245 	 * Set resid to the amount of packet data following the
1246 	 * trailer header.
1247 	 * Finally, copy residual data into mbuf chain.
1248 	 */
1249 	if (etype >= ETHERTYPE_TRAIL &&
1250 	    etype < ETHERTYPE_TRAIL+ETHERTYPE_NTRAILER) {
1251 
1252 		off = (etype - ETHERTYPE_TRAIL) << 9;
1253 		if ((off + sizeof(struct trailer_header)) > len)
1254 			goto bad;	/* insanity */
1255 
1256 		eh->ether_type = *ringoffset(sc, buf, off, u_short *);
1257 		resid = ntohs(*ringoffset(sc, buf, off+2, u_short *));
1258 
1259 		if ((off + resid) > len) goto bad;	/* insanity */
1260 
1261 		resid -= sizeof(struct trailer_header);
1262 		if (resid < 0) goto bad;	/* insanity */
1263 
1264 		m = ae_ring_to_mbuf(sc, ringoffset(sc, buf, off+4, char *), head, resid);
1265 		if (m == 0) goto bad;
1266 
1267 		len = off;
1268 		head->m_pkthdr.len -= 4; /* subtract trailer header */
1269 	}
1270 
1271 	/*
1272 	 * Pull packet off interface. Or if this was a trailer packet,
1273 	 * the data portion is appended.
1274 	 */
1275 	m = ae_ring_to_mbuf(sc, buf, m, len);
1276 	if (m == 0) goto bad;
1277 
1278 #if NBPFILTER > 0
1279 	/*
1280 	 * Check if there's a BPF listener on this interface.
1281 	 * If so, hand off the raw packet to bpf.
1282 	 */
1283 	if (sc->bpf) {
1284 		bpf_mtap(sc->bpf, head);
1285 
1286 		/*
1287 		 * Note that the interface cannot be in promiscuous mode if
1288 		 * there are no BPF listeners.  And if we are in promiscuous
1289 		 * mode, we have to check if this packet is really ours.
1290 		 *
1291 		 * XXX This test does not support multicasts.
1292 		 */
1293 		if ((sc->arpcom.ac_if.if_flags & IFF_PROMISC) &&
1294 			bcmp(eh->ether_dhost, sc->arpcom.ac_enaddr,
1295 				sizeof(eh->ether_dhost)) != 0 &&
1296 			bcmp(eh->ether_dhost, etherbroadcastaddr,
1297 				sizeof(eh->ether_dhost)) != 0) {
1298 
1299 			m_freem(head);
1300 			return;
1301 		}
1302 	}
1303 #endif
1304 
1305 	/*
1306 	 * Fix up data start offset in mbuf to point past ether header
1307 	 */
1308 	m_adj(head, sizeof(struct ether_header));
1309 
1310 	ether_input(&sc->arpcom.ac_if, eh, head);
1311 	return;
1312 
1313 bad:	if (head)
1314 		m_freem(head);
1315 	return;
1316 }
1317 
1318 /*
1319  * Supporting routines
1320  */
1321 
1322 /*
1323  * Given a source and destination address, copy 'amount' of a packet from
1324  *	the ring buffer into a linear destination buffer. Takes into account
1325  *	ring-wrap.
1326  */
1327 static inline char *
1328 ae_ring_copy(sc,src,dst,amount)
1329 	struct ae_softc *sc;
1330 	char	*src;
1331 	char	*dst;
1332 	u_short	amount;
1333 {
1334 	u_short	tmp_amount;
1335 
1336 	/* does copy wrap to lower addr in ring buffer? */
1337 	if (src + amount > sc->smem_end) {
1338 		tmp_amount = sc->smem_end - src;
1339 		bbcopy(src, dst, tmp_amount);/* copy amount up to end of smem */
1340 		amount -= tmp_amount;
1341 		src = sc->smem_ring;
1342 		dst += tmp_amount;
1343 	}
1344 
1345 	bbcopy(src, dst, amount);
1346 
1347 	return(src + amount);
1348 }
1349 
1350 /*
1351  * Copy data from receive buffer to end of mbuf chain
1352  * allocate additional mbufs as needed. return pointer
1353  * to last mbuf in chain.
1354  * sc = ed info (softc)
1355  * src = pointer in ed ring buffer
1356  * dst = pointer to last mbuf in mbuf chain to copy to
1357  * amount = amount of data to copy
1358  */
1359 struct mbuf *
1360 ae_ring_to_mbuf(sc,src,dst,total_len)
1361 	struct ae_softc *sc;
1362 	char *src;
1363 	struct mbuf *dst;
1364 	u_short total_len;
1365 {
1366 	register struct mbuf *m = dst;
1367 
1368 	while (total_len) {
1369 		register u_short amount = min(total_len, M_TRAILINGSPACE(m));
1370 
1371 		if (amount == 0) { /* no more data in this mbuf, alloc another */
1372 			/*
1373 			 * If there is enough data for an mbuf cluster, attempt
1374 			 * 	to allocate one of those, otherwise, a regular
1375 			 *	mbuf will do.
1376 			 * Note that a regular mbuf is always required, even if
1377 			 *	we get a cluster - getting a cluster does not
1378 			 *	allocate any mbufs, and one is needed to assign
1379 			 *	the cluster to. The mbuf that has a cluster
1380 			 *	extension can not be used to contain data - only
1381 			 *	the cluster can contain data.
1382 			 */
1383 			dst = m;
1384 			MGET(m, M_DONTWAIT, MT_DATA);
1385 			if (m == 0)
1386 				return (0);
1387 
1388 			if (total_len >= MINCLSIZE)
1389 				MCLGET(m, M_DONTWAIT);
1390 
1391 			m->m_len = 0;
1392 			dst->m_next = m;
1393 			amount = min(total_len, M_TRAILINGSPACE(m));
1394 		}
1395 
1396 		src = ae_ring_copy(sc, src, mtod(m, caddr_t) + m->m_len, amount);
1397 
1398 		m->m_len += amount;
1399 		total_len -= amount;
1400 
1401 	}
1402 	return (m);
1403 }
1404