xref: /freebsd/sys/dev/aic7xxx/aic7xxx_inline.h (revision 7afc53b8dfcc7d5897920ce6cc7e842fbb4ab813)
1 /*-
2  * Inline routines shareable across OS platforms.
3  *
4  * Copyright (c) 1994-2001 Justin T. Gibbs.
5  * Copyright (c) 2000-2001 Adaptec Inc.
6  * All rights reserved.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions, and the following disclaimer,
13  *    without modification.
14  * 2. Redistributions in binary form must reproduce at minimum a disclaimer
15  *    substantially similar to the "NO WARRANTY" disclaimer below
16  *    ("Disclaimer") and any redistribution must be conditioned upon
17  *    including a substantially similar Disclaimer requirement for further
18  *    binary redistribution.
19  * 3. Neither the names of the above-listed copyright holders nor the names
20  *    of any contributors may be used to endorse or promote products derived
21  *    from this software without specific prior written permission.
22  *
23  * Alternatively, this software may be distributed under the terms of the
24  * GNU General Public License ("GPL") version 2 as published by the Free
25  * Software Foundation.
26  *
27  * NO WARRANTY
28  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
29  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
30  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
31  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
32  * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
33  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
34  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
35  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
36  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
37  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
38  * POSSIBILITY OF SUCH DAMAGES.
39  *
40  * $Id: //depot/aic7xxx/aic7xxx/aic7xxx_inline.h#47 $
41  *
42  * $FreeBSD$
43  */
44 
45 #ifndef _AIC7XXX_INLINE_H_
46 #define _AIC7XXX_INLINE_H_
47 
48 /************************* Sequencer Execution Control ************************/
49 static __inline void ahc_pause_bug_fix(struct ahc_softc *ahc);
50 static __inline int  ahc_is_paused(struct ahc_softc *ahc);
51 static __inline void ahc_pause(struct ahc_softc *ahc);
52 static __inline void ahc_unpause(struct ahc_softc *ahc);
53 
54 /*
55  * Work around any chip bugs related to halting sequencer execution.
56  * On Ultra2 controllers, we must clear the CIOBUS stretch signal by
57  * reading a register that will set this signal and deassert it.
58  * Without this workaround, if the chip is paused, by an interrupt or
59  * manual pause while accessing scb ram, accesses to certain registers
60  * will hang the system (infinite pci retries).
61  */
62 static __inline void
63 ahc_pause_bug_fix(struct ahc_softc *ahc)
64 {
65 	if ((ahc->features & AHC_ULTRA2) != 0)
66 		(void)ahc_inb(ahc, CCSCBCTL);
67 }
68 
69 /*
70  * Determine whether the sequencer has halted code execution.
71  * Returns non-zero status if the sequencer is stopped.
72  */
73 static __inline int
74 ahc_is_paused(struct ahc_softc *ahc)
75 {
76 	return ((ahc_inb(ahc, HCNTRL) & PAUSE) != 0);
77 }
78 
79 /*
80  * Request that the sequencer stop and wait, indefinitely, for it
81  * to stop.  The sequencer will only acknowledge that it is paused
82  * once it has reached an instruction boundary and PAUSEDIS is
83  * cleared in the SEQCTL register.  The sequencer may use PAUSEDIS
84  * for critical sections.
85  */
86 static __inline void
87 ahc_pause(struct ahc_softc *ahc)
88 {
89 	ahc_outb(ahc, HCNTRL, ahc->pause);
90 
91 	/*
92 	 * Since the sequencer can disable pausing in a critical section, we
93 	 * must loop until it actually stops.
94 	 */
95 	while (ahc_is_paused(ahc) == 0)
96 		;
97 
98 	ahc_pause_bug_fix(ahc);
99 }
100 
101 /*
102  * Allow the sequencer to continue program execution.
103  * We check here to ensure that no additional interrupt
104  * sources that would cause the sequencer to halt have been
105  * asserted.  If, for example, a SCSI bus reset is detected
106  * while we are fielding a different, pausing, interrupt type,
107  * we don't want to release the sequencer before going back
108  * into our interrupt handler and dealing with this new
109  * condition.
110  */
111 static __inline void
112 ahc_unpause(struct ahc_softc *ahc)
113 {
114 	if ((ahc_inb(ahc, INTSTAT) & (SCSIINT | SEQINT | BRKADRINT)) == 0)
115 		ahc_outb(ahc, HCNTRL, ahc->unpause);
116 }
117 
118 /*********************** Untagged Transaction Routines ************************/
119 static __inline void	ahc_freeze_untagged_queues(struct ahc_softc *ahc);
120 static __inline void	ahc_release_untagged_queues(struct ahc_softc *ahc);
121 
122 /*
123  * Block our completion routine from starting the next untagged
124  * transaction for this target or target lun.
125  */
126 static __inline void
127 ahc_freeze_untagged_queues(struct ahc_softc *ahc)
128 {
129 	if ((ahc->flags & AHC_SCB_BTT) == 0)
130 		ahc->untagged_queue_lock++;
131 }
132 
133 /*
134  * Allow the next untagged transaction for this target or target lun
135  * to be executed.  We use a counting semaphore to allow the lock
136  * to be acquired recursively.  Once the count drops to zero, the
137  * transaction queues will be run.
138  */
139 static __inline void
140 ahc_release_untagged_queues(struct ahc_softc *ahc)
141 {
142 	if ((ahc->flags & AHC_SCB_BTT) == 0) {
143 		ahc->untagged_queue_lock--;
144 		if (ahc->untagged_queue_lock == 0)
145 			ahc_run_untagged_queues(ahc);
146 	}
147 }
148 
149 /************************** Memory mapping routines ***************************/
150 static __inline struct ahc_dma_seg *
151 			ahc_sg_bus_to_virt(struct scb *scb,
152 					   uint32_t sg_busaddr);
153 static __inline uint32_t
154 			ahc_sg_virt_to_bus(struct scb *scb,
155 					   struct ahc_dma_seg *sg);
156 static __inline uint32_t
157 			ahc_hscb_busaddr(struct ahc_softc *ahc, u_int index);
158 static __inline void	ahc_sync_scb(struct ahc_softc *ahc,
159 				     struct scb *scb, int op);
160 static __inline void	ahc_sync_sglist(struct ahc_softc *ahc,
161 					struct scb *scb, int op);
162 static __inline uint32_t
163 			ahc_targetcmd_offset(struct ahc_softc *ahc,
164 					     u_int index);
165 
166 static __inline struct ahc_dma_seg *
167 ahc_sg_bus_to_virt(struct scb *scb, uint32_t sg_busaddr)
168 {
169 	int sg_index;
170 
171 	sg_index = (sg_busaddr - scb->sg_list_phys)/sizeof(struct ahc_dma_seg);
172 	/* sg_list_phys points to entry 1, not 0 */
173 	sg_index++;
174 
175 	return (&scb->sg_list[sg_index]);
176 }
177 
178 static __inline uint32_t
179 ahc_sg_virt_to_bus(struct scb *scb, struct ahc_dma_seg *sg)
180 {
181 	int sg_index;
182 
183 	/* sg_list_phys points to entry 1, not 0 */
184 	sg_index = sg - &scb->sg_list[1];
185 
186 	return (scb->sg_list_phys + (sg_index * sizeof(*scb->sg_list)));
187 }
188 
189 static __inline uint32_t
190 ahc_hscb_busaddr(struct ahc_softc *ahc, u_int index)
191 {
192 	return (ahc->scb_data->hscb_busaddr
193 		+ (sizeof(struct hardware_scb) * index));
194 }
195 
196 static __inline void
197 ahc_sync_scb(struct ahc_softc *ahc, struct scb *scb, int op)
198 {
199 	aic_dmamap_sync(ahc, ahc->scb_data->hscb_dmat,
200 			ahc->scb_data->hscb_dmamap,
201 			/*offset*/(scb->hscb - ahc->hscbs) * sizeof(*scb->hscb),
202 			/*len*/sizeof(*scb->hscb), op);
203 }
204 
205 static __inline void
206 ahc_sync_sglist(struct ahc_softc *ahc, struct scb *scb, int op)
207 {
208 	if (scb->sg_count == 0)
209 		return;
210 
211 	aic_dmamap_sync(ahc, ahc->scb_data->sg_dmat, scb->sg_map->sg_dmamap,
212 			/*offset*/(scb->sg_list - scb->sg_map->sg_vaddr)
213 				* sizeof(struct ahc_dma_seg),
214 			/*len*/sizeof(struct ahc_dma_seg) * scb->sg_count, op);
215 }
216 
217 static __inline uint32_t
218 ahc_targetcmd_offset(struct ahc_softc *ahc, u_int index)
219 {
220 	return (((uint8_t *)&ahc->targetcmds[index]) - ahc->qoutfifo);
221 }
222 
223 /******************************** Debugging ***********************************/
224 static __inline char *ahc_name(struct ahc_softc *ahc);
225 
226 static __inline char *
227 ahc_name(struct ahc_softc *ahc)
228 {
229 	return (ahc->name);
230 }
231 
232 /*********************** Miscelaneous Support Functions ***********************/
233 
234 static __inline void	ahc_update_residual(struct ahc_softc *ahc,
235 					    struct scb *scb);
236 static __inline struct ahc_initiator_tinfo *
237 			ahc_fetch_transinfo(struct ahc_softc *ahc,
238 					    char channel, u_int our_id,
239 					    u_int remote_id,
240 					    struct ahc_tmode_tstate **tstate);
241 static __inline uint16_t
242 			ahc_inw(struct ahc_softc *ahc, u_int port);
243 static __inline void	ahc_outw(struct ahc_softc *ahc, u_int port,
244 				 u_int value);
245 static __inline uint32_t
246 			ahc_inl(struct ahc_softc *ahc, u_int port);
247 static __inline void	ahc_outl(struct ahc_softc *ahc, u_int port,
248 				 uint32_t value);
249 static __inline uint64_t
250 			ahc_inq(struct ahc_softc *ahc, u_int port);
251 static __inline void	ahc_outq(struct ahc_softc *ahc, u_int port,
252 				 uint64_t value);
253 static __inline struct scb*
254 			ahc_get_scb(struct ahc_softc *ahc);
255 static __inline void	ahc_free_scb(struct ahc_softc *ahc, struct scb *scb);
256 static __inline void	ahc_swap_with_next_hscb(struct ahc_softc *ahc,
257 						struct scb *scb);
258 static __inline void	ahc_queue_scb(struct ahc_softc *ahc, struct scb *scb);
259 static __inline struct scsi_sense_data *
260 			ahc_get_sense_buf(struct ahc_softc *ahc,
261 					  struct scb *scb);
262 static __inline uint32_t
263 			ahc_get_sense_bufaddr(struct ahc_softc *ahc,
264 					      struct scb *scb);
265 
266 /*
267  * Determine whether the sequencer reported a residual
268  * for this SCB/transaction.
269  */
270 static __inline void
271 ahc_update_residual(struct ahc_softc *ahc, struct scb *scb)
272 {
273 	uint32_t sgptr;
274 
275 	sgptr = aic_le32toh(scb->hscb->sgptr);
276 	if ((sgptr & SG_RESID_VALID) != 0)
277 		ahc_calc_residual(ahc, scb);
278 }
279 
280 /*
281  * Return pointers to the transfer negotiation information
282  * for the specified our_id/remote_id pair.
283  */
284 static __inline struct ahc_initiator_tinfo *
285 ahc_fetch_transinfo(struct ahc_softc *ahc, char channel, u_int our_id,
286 		    u_int remote_id, struct ahc_tmode_tstate **tstate)
287 {
288 	/*
289 	 * Transfer data structures are stored from the perspective
290 	 * of the target role.  Since the parameters for a connection
291 	 * in the initiator role to a given target are the same as
292 	 * when the roles are reversed, we pretend we are the target.
293 	 */
294 	if (channel == 'B')
295 		our_id += 8;
296 	*tstate = ahc->enabled_targets[our_id];
297 	return (&(*tstate)->transinfo[remote_id]);
298 }
299 
300 static __inline uint16_t
301 ahc_inw(struct ahc_softc *ahc, u_int port)
302 {
303 	return ((ahc_inb(ahc, port+1) << 8) | ahc_inb(ahc, port));
304 }
305 
306 static __inline void
307 ahc_outw(struct ahc_softc *ahc, u_int port, u_int value)
308 {
309 	ahc_outb(ahc, port, value & 0xFF);
310 	ahc_outb(ahc, port+1, (value >> 8) & 0xFF);
311 }
312 
313 static __inline uint32_t
314 ahc_inl(struct ahc_softc *ahc, u_int port)
315 {
316 	return ((ahc_inb(ahc, port))
317 	      | (ahc_inb(ahc, port+1) << 8)
318 	      | (ahc_inb(ahc, port+2) << 16)
319 	      | (ahc_inb(ahc, port+3) << 24));
320 }
321 
322 static __inline void
323 ahc_outl(struct ahc_softc *ahc, u_int port, uint32_t value)
324 {
325 	ahc_outb(ahc, port, (value) & 0xFF);
326 	ahc_outb(ahc, port+1, ((value) >> 8) & 0xFF);
327 	ahc_outb(ahc, port+2, ((value) >> 16) & 0xFF);
328 	ahc_outb(ahc, port+3, ((value) >> 24) & 0xFF);
329 }
330 
331 static __inline uint64_t
332 ahc_inq(struct ahc_softc *ahc, u_int port)
333 {
334 	return ((ahc_inb(ahc, port))
335 	      | (ahc_inb(ahc, port+1) << 8)
336 	      | (ahc_inb(ahc, port+2) << 16)
337 	      | (ahc_inb(ahc, port+3) << 24)
338 	      | (((uint64_t)ahc_inb(ahc, port+4)) << 32)
339 	      | (((uint64_t)ahc_inb(ahc, port+5)) << 40)
340 	      | (((uint64_t)ahc_inb(ahc, port+6)) << 48)
341 	      | (((uint64_t)ahc_inb(ahc, port+7)) << 56));
342 }
343 
344 static __inline void
345 ahc_outq(struct ahc_softc *ahc, u_int port, uint64_t value)
346 {
347 	ahc_outb(ahc, port, value & 0xFF);
348 	ahc_outb(ahc, port+1, (value >> 8) & 0xFF);
349 	ahc_outb(ahc, port+2, (value >> 16) & 0xFF);
350 	ahc_outb(ahc, port+3, (value >> 24) & 0xFF);
351 	ahc_outb(ahc, port+4, (value >> 32) & 0xFF);
352 	ahc_outb(ahc, port+5, (value >> 40) & 0xFF);
353 	ahc_outb(ahc, port+6, (value >> 48) & 0xFF);
354 	ahc_outb(ahc, port+7, (value >> 56) & 0xFF);
355 }
356 
357 /*
358  * Get a free scb. If there are none, see if we can allocate a new SCB.
359  */
360 static __inline struct scb *
361 ahc_get_scb(struct ahc_softc *ahc)
362 {
363 	struct scb *scb;
364 
365 	if ((scb = SLIST_FIRST(&ahc->scb_data->free_scbs)) == NULL) {
366 		ahc_alloc_scbs(ahc);
367 		scb = SLIST_FIRST(&ahc->scb_data->free_scbs);
368 		if (scb == NULL)
369 			return (NULL);
370 	}
371 	SLIST_REMOVE_HEAD(&ahc->scb_data->free_scbs, links.sle);
372 	return (scb);
373 }
374 
375 /*
376  * Return an SCB resource to the free list.
377  */
378 static __inline void
379 ahc_free_scb(struct ahc_softc *ahc, struct scb *scb)
380 {
381 	struct hardware_scb *hscb;
382 
383 	hscb = scb->hscb;
384 	/* Clean up for the next user */
385 	ahc->scb_data->scbindex[hscb->tag] = NULL;
386 	scb->flags = SCB_FLAG_NONE;
387 	hscb->control = 0;
388 
389 	SLIST_INSERT_HEAD(&ahc->scb_data->free_scbs, scb, links.sle);
390 
391 	/* Notify the OSM that a resource is now available. */
392 	aic_platform_scb_free(ahc, scb);
393 }
394 
395 static __inline struct scb *
396 ahc_lookup_scb(struct ahc_softc *ahc, u_int tag)
397 {
398 	struct scb* scb;
399 
400 	scb = ahc->scb_data->scbindex[tag];
401 	if (scb != NULL)
402 		ahc_sync_scb(ahc, scb,
403 			     BUS_DMASYNC_POSTREAD|BUS_DMASYNC_POSTWRITE);
404 	return (scb);
405 }
406 
407 static __inline void
408 ahc_swap_with_next_hscb(struct ahc_softc *ahc, struct scb *scb)
409 {
410 	struct hardware_scb *q_hscb;
411 	u_int  saved_tag;
412 
413 	/*
414 	 * Our queuing method is a bit tricky.  The card
415 	 * knows in advance which HSCB to download, and we
416 	 * can't disappoint it.  To achieve this, the next
417 	 * SCB to download is saved off in ahc->next_queued_scb.
418 	 * When we are called to queue "an arbitrary scb",
419 	 * we copy the contents of the incoming HSCB to the one
420 	 * the sequencer knows about, swap HSCB pointers and
421 	 * finally assign the SCB to the tag indexed location
422 	 * in the scb_array.  This makes sure that we can still
423 	 * locate the correct SCB by SCB_TAG.
424 	 */
425 	q_hscb = ahc->next_queued_scb->hscb;
426 	saved_tag = q_hscb->tag;
427 	memcpy(q_hscb, scb->hscb, sizeof(*scb->hscb));
428 	if ((scb->flags & SCB_CDB32_PTR) != 0) {
429 		q_hscb->shared_data.cdb_ptr =
430 		    aic_htole32(ahc_hscb_busaddr(ahc, q_hscb->tag)
431 			      + offsetof(struct hardware_scb, cdb32));
432 	}
433 	q_hscb->tag = saved_tag;
434 	q_hscb->next = scb->hscb->tag;
435 
436 	/* Now swap HSCB pointers. */
437 	ahc->next_queued_scb->hscb = scb->hscb;
438 	scb->hscb = q_hscb;
439 
440 	/* Now define the mapping from tag to SCB in the scbindex */
441 	ahc->scb_data->scbindex[scb->hscb->tag] = scb;
442 }
443 
444 /*
445  * Tell the sequencer about a new transaction to execute.
446  */
447 static __inline void
448 ahc_queue_scb(struct ahc_softc *ahc, struct scb *scb)
449 {
450 	ahc_swap_with_next_hscb(ahc, scb);
451 
452 	if (scb->hscb->tag == SCB_LIST_NULL
453 	 || scb->hscb->next == SCB_LIST_NULL)
454 		panic("Attempt to queue invalid SCB tag %x:%x\n",
455 		      scb->hscb->tag, scb->hscb->next);
456 
457 	/*
458 	 * Setup data "oddness".
459 	 */
460 	scb->hscb->lun &= LID;
461 	if (aic_get_transfer_length(scb) & 0x1)
462 		scb->hscb->lun |= SCB_XFERLEN_ODD;
463 
464 	/*
465 	 * Keep a history of SCBs we've downloaded in the qinfifo.
466 	 */
467 	ahc->qinfifo[ahc->qinfifonext++] = scb->hscb->tag;
468 
469 	/*
470 	 * Make sure our data is consistent from the
471 	 * perspective of the adapter.
472 	 */
473 	ahc_sync_scb(ahc, scb, BUS_DMASYNC_PREREAD|BUS_DMASYNC_PREWRITE);
474 
475 	/* Tell the adapter about the newly queued SCB */
476 	if ((ahc->features & AHC_QUEUE_REGS) != 0) {
477 		ahc_outb(ahc, HNSCB_QOFF, ahc->qinfifonext);
478 	} else {
479 		if ((ahc->features & AHC_AUTOPAUSE) == 0)
480 			ahc_pause(ahc);
481 		ahc_outb(ahc, KERNEL_QINPOS, ahc->qinfifonext);
482 		if ((ahc->features & AHC_AUTOPAUSE) == 0)
483 			ahc_unpause(ahc);
484 	}
485 }
486 
487 static __inline struct scsi_sense_data *
488 ahc_get_sense_buf(struct ahc_softc *ahc, struct scb *scb)
489 {
490 	int offset;
491 
492 	offset = scb - ahc->scb_data->scbarray;
493 	return (&ahc->scb_data->sense[offset]);
494 }
495 
496 static __inline uint32_t
497 ahc_get_sense_bufaddr(struct ahc_softc *ahc, struct scb *scb)
498 {
499 	int offset;
500 
501 	offset = scb - ahc->scb_data->scbarray;
502 	return (ahc->scb_data->sense_busaddr
503 	      + (offset * sizeof(struct scsi_sense_data)));
504 }
505 
506 /************************** Interrupt Processing ******************************/
507 static __inline void	ahc_sync_qoutfifo(struct ahc_softc *ahc, int op);
508 static __inline void	ahc_sync_tqinfifo(struct ahc_softc *ahc, int op);
509 static __inline u_int	ahc_check_cmdcmpltqueues(struct ahc_softc *ahc);
510 static __inline int	ahc_intr(struct ahc_softc *ahc);
511 
512 static __inline void
513 ahc_sync_qoutfifo(struct ahc_softc *ahc, int op)
514 {
515 	aic_dmamap_sync(ahc, ahc->shared_data_dmat, ahc->shared_data_dmamap,
516 			/*offset*/0, /*len*/256, op);
517 }
518 
519 static __inline void
520 ahc_sync_tqinfifo(struct ahc_softc *ahc, int op)
521 {
522 #ifdef AHC_TARGET_MODE
523 	if ((ahc->flags & AHC_TARGETROLE) != 0) {
524 		aic_dmamap_sync(ahc, ahc->shared_data_dmat,
525 				ahc->shared_data_dmamap,
526 				ahc_targetcmd_offset(ahc, 0),
527 				sizeof(struct target_cmd) * AHC_TMODE_CMDS,
528 				op);
529 	}
530 #endif
531 }
532 
533 /*
534  * See if the firmware has posted any completed commands
535  * into our in-core command complete fifos.
536  */
537 #define AHC_RUN_QOUTFIFO 0x1
538 #define AHC_RUN_TQINFIFO 0x2
539 static __inline u_int
540 ahc_check_cmdcmpltqueues(struct ahc_softc *ahc)
541 {
542 	u_int retval;
543 
544 	retval = 0;
545 	aic_dmamap_sync(ahc, ahc->shared_data_dmat, ahc->shared_data_dmamap,
546 			/*offset*/ahc->qoutfifonext, /*len*/1,
547 			BUS_DMASYNC_POSTREAD);
548 	if (ahc->qoutfifo[ahc->qoutfifonext] != SCB_LIST_NULL)
549 		retval |= AHC_RUN_QOUTFIFO;
550 #ifdef AHC_TARGET_MODE
551 	if ((ahc->flags & AHC_TARGETROLE) != 0
552 	 && (ahc->flags & AHC_TQINFIFO_BLOCKED) == 0) {
553 		aic_dmamap_sync(ahc, ahc->shared_data_dmat,
554 				ahc->shared_data_dmamap,
555 				ahc_targetcmd_offset(ahc, ahc->tqinfifofnext),
556 				/*len*/sizeof(struct target_cmd),
557 				BUS_DMASYNC_POSTREAD);
558 		if (ahc->targetcmds[ahc->tqinfifonext].cmd_valid != 0)
559 			retval |= AHC_RUN_TQINFIFO;
560 	}
561 #endif
562 	return (retval);
563 }
564 
565 /*
566  * Catch an interrupt from the adapter
567  */
568 static __inline int
569 ahc_intr(struct ahc_softc *ahc)
570 {
571 	u_int	intstat;
572 
573 	if ((ahc->pause & INTEN) == 0) {
574 		/*
575 		 * Our interrupt is not enabled on the chip
576 		 * and may be disabled for re-entrancy reasons,
577 		 * so just return.  This is likely just a shared
578 		 * interrupt.
579 		 */
580 		return (0);
581 	}
582 	/*
583 	 * Instead of directly reading the interrupt status register,
584 	 * infer the cause of the interrupt by checking our in-core
585 	 * completion queues.  This avoids a costly PCI bus read in
586 	 * most cases.
587 	 */
588 	if ((ahc->flags & (AHC_ALL_INTERRUPTS|AHC_EDGE_INTERRUPT)) == 0
589 	 && (ahc_check_cmdcmpltqueues(ahc) != 0))
590 		intstat = CMDCMPLT;
591 	else {
592 		intstat = ahc_inb(ahc, INTSTAT);
593 	}
594 
595 	if ((intstat & INT_PEND) == 0) {
596 #if AIC_PCI_CONFIG > 0
597 		if (ahc->unsolicited_ints > 500) {
598 			ahc->unsolicited_ints = 0;
599 			if ((ahc->chip & AHC_PCI) != 0
600 			 && (ahc_inb(ahc, ERROR) & PCIERRSTAT) != 0)
601 				ahc->bus_intr(ahc);
602 		}
603 #endif
604 		ahc->unsolicited_ints++;
605 		return (0);
606 	}
607 	ahc->unsolicited_ints = 0;
608 
609 	if (intstat & CMDCMPLT) {
610 		ahc_outb(ahc, CLRINT, CLRCMDINT);
611 
612 		/*
613 		 * Ensure that the chip sees that we've cleared
614 		 * this interrupt before we walk the output fifo.
615 		 * Otherwise, we may, due to posted bus writes,
616 		 * clear the interrupt after we finish the scan,
617 		 * and after the sequencer has added new entries
618 		 * and asserted the interrupt again.
619 		 */
620 		ahc_flush_device_writes(ahc);
621 		ahc_run_qoutfifo(ahc);
622 #ifdef AHC_TARGET_MODE
623 		if ((ahc->flags & AHC_TARGETROLE) != 0)
624 			ahc_run_tqinfifo(ahc, /*paused*/FALSE);
625 #endif
626 	}
627 
628 	/*
629 	 * Handle statuses that may invalidate our cached
630 	 * copy of INTSTAT separately.
631 	 */
632 	if (intstat == 0xFF && (ahc->features & AHC_REMOVABLE) != 0) {
633 		/* Hot eject.  Do nothing */
634 	} else if (intstat & BRKADRINT) {
635 		ahc_handle_brkadrint(ahc);
636 	} else if ((intstat & (SEQINT|SCSIINT)) != 0) {
637 
638 		ahc_pause_bug_fix(ahc);
639 
640 		if ((intstat & SEQINT) != 0)
641 			ahc_handle_seqint(ahc, intstat);
642 
643 		if ((intstat & SCSIINT) != 0)
644 			ahc_handle_scsiint(ahc, intstat);
645 	}
646 	return (1);
647 }
648 
649 #endif  /* _AIC7XXX_INLINE_H_ */
650