xref: /dragonfly/sys/dev/disk/nata/ata-queue.c (revision 73e0051e)
1 /*-
2  * Copyright (c) 1998 - 2006 S�ren Schmidt <sos@FreeBSD.org>
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer,
10  *    without modification, immediately at the beginning of the file.
11  * 2. Redistributions in binary form must reproduce the above copyright
12  *    notice, this list of conditions and the following disclaimer in the
13  *    documentation and/or other materials provided with the distribution.
14  *
15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25  *
26  * $FreeBSD: src/sys/dev/ata/ata-queue.c,v 1.67 2007/01/27 21:15:58 remko Exp $
27  * $DragonFly: src/sys/dev/disk/nata/ata-queue.c,v 1.11 2008/09/23 17:43:41 dillon Exp $
28  */
29 
30 #include "opt_ata.h"
31 
32 #include <sys/param.h>
33 #include <sys/bus.h>
34 #include <sys/callout.h>
35 #include <sys/nata.h>
36 #include <sys/queue.h>
37 #include <sys/spinlock2.h>
38 #include <sys/buf.h>
39 #include <sys/systm.h>
40 #include <sys/taskqueue.h>
41 
42 #include "ata-all.h"
43 #include "ata_if.h"
44 
45 /* prototypes */
46 static void ata_completed(void *, int);
47 static void ata_sort_queue(struct ata_channel *ch, struct ata_request *request);
48 static void atawritereorder(struct ata_channel *ch);
49 static char *ata_skey2str(u_int8_t);
50 
51 void
52 ata_queue_init(struct ata_channel *ch)
53 {
54     TAILQ_INIT(&ch->ata_queue);
55     ch->reorder = 0;
56     ch->transition = NULL;
57 }
58 
59 void
60 ata_queue_request(struct ata_request *request)
61 {
62     struct ata_channel *ch;
63 
64     /* treat request as virgin (this might be an ATA_R_REQUEUE) */
65     request->result = request->status = request->error = 0;
66 
67     /* check that that the device is still valid */
68     if (!(request->parent = device_get_parent(request->dev))) {
69 	request->result = ENXIO;
70 	if (request->callback)
71 	    (request->callback)(request);
72 	return;
73     }
74     ch = device_get_softc(request->parent);
75     callout_init_mp(&request->callout);	/* serialization done via state_mtx */
76     if (!request->callback && !(request->flags & ATA_R_REQUEUE))
77 	spin_init(&request->done);
78 
79     /* in ATA_STALL_QUEUE state we call HW directly */
80     if ((ch->state & ATA_STALL_QUEUE) && (request->flags & ATA_R_CONTROL)) {
81 	spin_lock_wr(&ch->state_mtx);
82 	ch->running = request;
83 	if (ch->hw.begin_transaction(request) == ATA_OP_FINISHED) {
84 	    ch->running = NULL;
85 	    if (!request->callback)
86 		spin_uninit(&request->done);
87 	    spin_unlock_wr(&ch->state_mtx);
88 	    return;
89 	}
90 	/* interlock against interrupt */
91 	request->flags |= ATA_R_HWCMDQUEUED;
92 	spin_unlock_wr(&ch->state_mtx);
93     }
94     /* otherwise put request on the locked queue at the specified location */
95     else  {
96 	spin_lock_wr(&ch->queue_mtx);
97 	if (request->flags & ATA_R_AT_HEAD) {
98 	    TAILQ_INSERT_HEAD(&ch->ata_queue, request, chain);
99 	} else if (request->flags & ATA_R_ORDERED) {
100 	    ata_sort_queue(ch, request);
101 	} else {
102 	    TAILQ_INSERT_TAIL(&ch->ata_queue, request, chain);
103 	    ch->transition = NULL;
104 	}
105 	spin_unlock_wr(&ch->queue_mtx);
106 	ATA_DEBUG_RQ(request, "queued");
107 	ata_start(ch->dev);
108     }
109 
110     /* if this is a requeued request callback/sleep we're done */
111     if (request->flags & ATA_R_REQUEUE)
112 	return;
113 
114     /* if this is not a callback wait until request is completed */
115     if (!request->callback) {
116 	ATA_DEBUG_RQ(request, "wait for completion");
117 	if (!dumping) {
118 	    /* interlock against wakeup */
119 	    spin_lock_wr(&request->done);
120 	    /* check if the request was completed already */
121 	    if (!(request->flags & ATA_R_COMPLETED))
122 		ssleep(request, &request->done, 0, "ATA request completion "
123 		       "wait", request->timeout * hz * 4);
124 	    spin_unlock_wr(&request->done);
125 	    /* check if the request was completed while sleeping */
126 	    if (!(request->flags & ATA_R_COMPLETED)) {
127 		/* apparently not */
128 		device_printf(request->dev, "WARNING - %s taskqueue timeout - "
129 			      "completing request directly\n",
130 			      ata_cmd2str(request));
131 		request->flags |= ATA_R_DANGER1;
132 		ata_completed(request, 0);
133 	    }
134 	}
135 	spin_uninit(&request->done);
136     }
137 }
138 
139 int
140 ata_controlcmd(device_t dev, u_int8_t command, u_int16_t feature,
141 	       u_int64_t lba, u_int16_t count)
142 {
143     struct ata_request *request = ata_alloc_request();
144     int error = ENOMEM;
145 
146     if (request) {
147 	request->dev = dev;
148 	request->u.ata.command = command;
149 	request->u.ata.lba = lba;
150 	request->u.ata.count = count;
151 	request->u.ata.feature = feature;
152 	request->flags = ATA_R_CONTROL;
153 	request->timeout = 1;
154 	request->retries = 0;
155 	ata_queue_request(request);
156 	error = request->result;
157 	ata_free_request(request);
158     }
159     return error;
160 }
161 
162 int
163 ata_atapicmd(device_t dev, u_int8_t *ccb, caddr_t data,
164 	     int count, int flags, int timeout)
165 {
166     struct ata_request *request = ata_alloc_request();
167     struct ata_device *atadev = device_get_softc(dev);
168     int error = ENOMEM;
169 
170     if (request) {
171 	request->dev = dev;
172 	if ((atadev->param.config & ATA_PROTO_MASK) == ATA_PROTO_ATAPI_12)
173 	    bcopy(ccb, request->u.atapi.ccb, 12);
174 	else
175 	    bcopy(ccb, request->u.atapi.ccb, 16);
176 	request->data = data;
177 	request->bytecount = count;
178 	request->transfersize = min(request->bytecount, 65534);
179 	request->flags = flags | ATA_R_ATAPI;
180 	request->timeout = timeout;
181 	request->retries = 0;
182 	ata_queue_request(request);
183 	error = request->result;
184 	ata_free_request(request);
185     }
186     return error;
187 }
188 
189 void
190 ata_start(device_t dev)
191 {
192     struct ata_channel *ch = device_get_softc(dev);
193     struct ata_request *request;
194     struct ata_composite *cptr;
195     int dependencies = 0;
196 
197     /* if we have a request on the queue try to get it running */
198     spin_lock_wr(&ch->queue_mtx);
199     if ((request = TAILQ_FIRST(&ch->ata_queue))) {
200 
201 	/* we need the locking function to get the lock for this channel */
202 	if (ATA_LOCKING(dev, ATA_LF_LOCK) == ch->unit) {
203 
204 	    /* check for composite dependencies */
205 	    if ((cptr = request->composite)) {
206 		spin_lock_wr(&cptr->lock);
207 		if ((request->flags & ATA_R_WRITE) &&
208 		    (cptr->wr_depend & cptr->rd_done) != cptr->wr_depend) {
209 		    dependencies = 1;
210 		}
211 		spin_unlock_wr(&cptr->lock);
212 	    }
213 
214 	    /* check we are in the right state and has no dependencies */
215 	    spin_lock_wr(&ch->state_mtx);
216 	    if (ch->state == ATA_IDLE && !dependencies) {
217 		ATA_DEBUG_RQ(request, "starting");
218 
219 		if (ch->transition == request)
220 		    ch->transition = TAILQ_NEXT(request, chain);
221 		TAILQ_REMOVE(&ch->ata_queue, request, chain);
222 		ch->running = request;
223 		ch->state = ATA_ACTIVE;
224 
225 		if (ch->hw.begin_transaction(request) == ATA_OP_FINISHED) {
226 		    ch->running = NULL;
227 		    ch->state = ATA_IDLE;
228 		    spin_unlock_wr(&ch->state_mtx);
229 		    spin_unlock_wr(&ch->queue_mtx);
230 		    ATA_LOCKING(dev, ATA_LF_UNLOCK);
231 		    ata_finish(request);
232 		    return;
233 		}
234 
235 		/* interlock against interrupt */
236 		request->flags |= ATA_R_HWCMDQUEUED;
237 
238 		if (dumping) {
239 		    spin_unlock_wr(&ch->state_mtx);
240 		    spin_unlock_wr(&ch->queue_mtx);
241 		    while (!ata_interrupt(ch))
242 			DELAY(10);
243 		    return;
244 		}
245 	    }
246 	    spin_unlock_wr(&ch->state_mtx);
247 	}
248     }
249     spin_unlock_wr(&ch->queue_mtx);
250 }
251 
252 void
253 ata_finish(struct ata_request *request)
254 {
255     struct ata_channel *ch = device_get_softc(request->parent);
256 
257     /*
258      * if in ATA_STALL_QUEUE state or request has ATA_R_DIRECT flags set
259      * we need to call ata_complete() directly here (no taskqueue involvement)
260      */
261     if (dumping ||
262 	(ch->state & ATA_STALL_QUEUE) || (request->flags & ATA_R_DIRECT)) {
263 	ATA_DEBUG_RQ(request, "finish directly");
264 	ata_completed(request, 0);
265     }
266     else {
267 	/* put request on the proper taskqueue for completion */
268 	/* XXX FreeBSD has some sort of bio_taskqueue code here */
269         TASK_INIT(&request->task, 0, ata_completed, request);
270 	ATA_DEBUG_RQ(request, "finish taskqueue_swi");
271 	taskqueue_enqueue(taskqueue_swi, &request->task);
272     }
273 }
274 
275 static void
276 ata_completed(void *context, int dummy)
277 {
278     struct ata_request *request = (struct ata_request *)context;
279     struct ata_channel *ch = device_get_softc(request->parent);
280     struct ata_device *atadev = device_get_softc(request->dev);
281     struct ata_composite *composite;
282 
283     if (request->flags & ATA_R_DANGER2) {
284 	device_printf(request->dev,
285 		      "WARNING - %s freeing taskqueue zombie request\n",
286 		      ata_cmd2str(request));
287 	request->flags &= ~(ATA_R_DANGER1 | ATA_R_DANGER2);
288 	ata_free_request(request);
289 	return;
290     }
291     if (request->flags & ATA_R_DANGER1)
292 	request->flags |= ATA_R_DANGER2;
293 
294     ATA_DEBUG_RQ(request, "completed entered");
295 
296     /* if we had a timeout, reinit channel and deal with the falldown */
297     if (request->flags & ATA_R_TIMEOUT) {
298 	/*
299 	 * if the channel is still present and
300 	 * reinit succeeds and
301 	 * the device doesn't get detached and
302 	 * there are retries left we reinject this request
303 	 */
304 	if (ch && !ata_reinit(ch->dev) && !request->result &&
305 	    (request->retries-- > 0)) {
306 	    if (!(request->flags & ATA_R_QUIET)) {
307 		device_printf(request->dev,
308 			      "TIMEOUT - %s retrying (%d retr%s left)",
309 			      ata_cmd2str(request), request->retries,
310 			      request->retries == 1 ? "y" : "ies");
311 		if (!(request->flags & (ATA_R_ATAPI | ATA_R_CONTROL)))
312 		    kprintf(" LBA=%ju", request->u.ata.lba);
313 		kprintf("\n");
314 	    }
315 	    request->flags &= ~(ATA_R_TIMEOUT | ATA_R_DEBUG);
316 	    request->flags |= (ATA_R_AT_HEAD | ATA_R_REQUEUE);
317 	    ATA_DEBUG_RQ(request, "completed reinject");
318 	    ata_queue_request(request);
319 	    return;
320 	}
321 
322 	/* ran out of good intentions so finish with error */
323 	if (!request->result) {
324 	    if (!(request->flags & ATA_R_QUIET)) {
325 		if (request->dev) {
326 		    device_printf(request->dev, "FAILURE - %s timed out",
327 				  ata_cmd2str(request));
328 		    if (!(request->flags & (ATA_R_ATAPI | ATA_R_CONTROL)))
329 			kprintf(" LBA=%ju", request->u.ata.lba);
330 		    kprintf("\n");
331 		}
332 	    }
333 	    request->result = EIO;
334 	}
335     }
336     else if (!(request->flags & ATA_R_ATAPI) ){
337 	/* if this is a soft ECC error warn about it */
338 	/* XXX SOS we could do WARF here */
339 	if ((request->status & (ATA_S_CORR | ATA_S_ERROR)) == ATA_S_CORR) {
340 	    device_printf(request->dev,
341 			  "WARNING - %s soft error (ECC corrected)",
342 			  ata_cmd2str(request));
343 	    if (!(request->flags & (ATA_R_ATAPI | ATA_R_CONTROL)))
344 		kprintf(" LBA=%ju", request->u.ata.lba);
345 	    kprintf("\n");
346 	}
347 
348 	/* if this is a UDMA CRC error we reinject if there are retries left */
349 	if (request->flags & ATA_R_DMA && request->error & ATA_E_ICRC) {
350 	    if (request->retries-- > 0) {
351 		device_printf(request->dev,
352 			      "WARNING - %s UDMA ICRC error (retrying request)",
353 			      ata_cmd2str(request));
354 		if (!(request->flags & (ATA_R_ATAPI | ATA_R_CONTROL)))
355 		    kprintf(" LBA=%ju", request->u.ata.lba);
356 		kprintf("\n");
357 		request->flags |= (ATA_R_AT_HEAD | ATA_R_REQUEUE);
358 		ata_queue_request(request);
359 		return;
360 	    }
361 	}
362     }
363 
364     switch (request->flags & ATA_R_ATAPI) {
365 
366     /* ATA errors */
367     default:
368 	if (!request->result && request->status & ATA_S_ERROR) {
369 	    if (!(request->flags & ATA_R_QUIET)) {
370 		device_printf(request->dev,
371 			      "FAILURE - %s status=%b error=%b",
372 			      ata_cmd2str(request),
373 			      request->status, "\20\10BUSY\7READY\6DMA_READY"
374 			      "\5DSC\4DRQ\3CORRECTABLE\2INDEX\1ERROR",
375 			      request->error, "\20\10ICRC\7UNCORRECTABLE"
376 			      "\6MEDIA_CHANGED\5NID_NOT_FOUND"
377 			      "\4MEDIA_CHANGE_REQEST"
378 			      "\3ABORTED\2NO_MEDIA\1ILLEGAL_LENGTH");
379 		if ((request->flags & ATA_R_DMA) &&
380 		    (request->dmastat & ATA_BMSTAT_ERROR))
381 		    kprintf(" dma=0x%02x", request->dmastat);
382 		if (!(request->flags & (ATA_R_ATAPI | ATA_R_CONTROL)))
383 		    kprintf(" LBA=%ju", request->u.ata.lba);
384 		kprintf("\n");
385 	    }
386 	    request->result = EIO;
387 	}
388 	break;
389 
390     /* ATAPI errors */
391     case ATA_R_ATAPI:
392 	/* skip if result already set */
393 	if (request->result)
394 	    break;
395 
396 	/* if we have a sensekey -> request sense from device */
397 	if ((request->error & ATA_E_ATAPI_SENSE_MASK) &&
398 	    (request->u.atapi.ccb[0] != ATAPI_REQUEST_SENSE)) {
399 	    static u_int8_t ccb[16] = { ATAPI_REQUEST_SENSE, 0, 0, 0,
400 					sizeof(struct atapi_sense),
401 					0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
402 
403 	    request->u.atapi.saved_cmd = request->u.atapi.ccb[0];
404 	    bcopy(ccb, request->u.atapi.ccb, 16);
405 	    request->data = (caddr_t)&request->u.atapi.sense;
406 	    request->bytecount = sizeof(struct atapi_sense);
407 	    request->donecount = 0;
408 	    request->transfersize = sizeof(struct atapi_sense);
409 	    request->timeout = ATA_DEFAULT_TIMEOUT;
410 	    request->flags &= (ATA_R_ATAPI | ATA_R_QUIET);
411 	    request->flags |= (ATA_R_READ | ATA_R_AT_HEAD | ATA_R_REQUEUE);
412 	    ATA_DEBUG_RQ(request, "autoissue request sense");
413 	    ata_queue_request(request);
414 	    return;
415 	}
416 
417 	switch (request->u.atapi.sense.key & ATA_SENSE_KEY_MASK) {
418 	case ATA_SENSE_RECOVERED_ERROR:
419 	    device_printf(request->dev, "WARNING - %s recovered error\n",
420 			  ata_cmd2str(request));
421 	    /* FALLTHROUGH */
422 
423 	case ATA_SENSE_NO_SENSE:
424 	    request->result = 0;
425 	    break;
426 
427 	case ATA_SENSE_NOT_READY:
428 	    request->result = EBUSY;
429 	    break;
430 
431 	case ATA_SENSE_UNIT_ATTENTION:
432 	    atadev->flags |= ATA_D_MEDIA_CHANGED;
433 	    request->result = EIO;
434 	    break;
435 
436 	default:
437 	    request->result = EIO;
438 	    if (request->flags & ATA_R_QUIET)
439 		break;
440 
441 	    device_printf(request->dev,
442 			  "FAILURE - %s %s asc=0x%02x ascq=0x%02x ",
443 			  ata_cmd2str(request), ata_skey2str(
444 			  (request->u.atapi.sense.key & ATA_SENSE_KEY_MASK)),
445 			  request->u.atapi.sense.asc,
446 			  request->u.atapi.sense.ascq);
447 	    if (request->u.atapi.sense.specific & ATA_SENSE_SPEC_VALID)
448 		kprintf("sks=0x%02x 0x%02x 0x%02x\n",
449 		       request->u.atapi.sense.specific & ATA_SENSE_SPEC_MASK,
450 		       request->u.atapi.sense.specific1,
451 		       request->u.atapi.sense.specific2);
452 	    else
453 		kprintf("\n");
454 	}
455 
456 	if ((request->u.atapi.sense.key & ATA_SENSE_KEY_MASK ?
457 	     request->u.atapi.sense.key & ATA_SENSE_KEY_MASK :
458 	     request->error))
459 	    request->result = EIO;
460     }
461 
462     ATA_DEBUG_RQ(request, "completed callback/wakeup");
463 
464     /* if we are part of a composite operation we need to maintain progress */
465     if ((composite = request->composite)) {
466 	int index = 0;
467 
468 	spin_lock_wr(&composite->lock);
469 
470 	/* update whats done */
471 	if (request->flags & ATA_R_READ)
472 	    composite->rd_done |= (1 << request->this);
473 	if (request->flags & ATA_R_WRITE)
474 	    composite->wr_done |= (1 << request->this);
475 
476 	/* find ready to go dependencies */
477 	if (composite->wr_depend &&
478 	    (composite->rd_done & composite->wr_depend)==composite->wr_depend &&
479 	    (composite->wr_needed & (~composite->wr_done))) {
480 	    index = composite->wr_needed & ~composite->wr_done;
481 	}
482 
483 	spin_unlock_wr(&composite->lock);
484 
485 	/* if we have any ready candidates kick them off */
486 	if (index) {
487 	    int bit;
488 
489 	    for (bit = 0; bit < MAX_COMPOSITES; bit++) {
490 		if (index & (1 << bit))
491 		    ata_start(device_get_parent(composite->request[bit]->dev));
492 	    }
493 	}
494     }
495 
496     /* get results back to the initiator for this request */
497     if (request->callback)
498 	(request->callback)(request);
499     else {
500 	spin_lock_wr(&request->done);
501 	request->flags |= ATA_R_COMPLETED;
502 	spin_unlock_wr(&request->done);
503 	wakeup_one(request);
504     }
505 
506     /* only call ata_start if channel is present */
507     if (ch)
508 	ata_start(ch->dev);
509 }
510 
511 void
512 ata_timeout(struct ata_request *request)
513 {
514     struct ata_channel *ch = device_get_softc(request->parent);
515 
516     /* acquire state_mtx, softclock_handler() doesn't do this for us */
517     spin_lock_wr(&ch->state_mtx);
518 
519     /*request->flags |= ATA_R_DEBUG;*/
520     ATA_DEBUG_RQ(request, "timeout");
521 
522     /*
523      * if we have an ATA_ACTIVE request running, we flag the request
524      * ATA_R_TIMEOUT so ata_finish will handle it correctly
525      * also NULL out the running request so we wont loose
526      * the race with an eventual interrupt arriving late
527      */
528     if (ch->state == ATA_ACTIVE) {
529 	request->flags |= ATA_R_TIMEOUT;
530 	spin_unlock_wr(&ch->state_mtx);
531 	ATA_LOCKING(ch->dev, ATA_LF_UNLOCK);
532 	ata_finish(request);
533     }
534     else {
535 	spin_unlock_wr(&ch->state_mtx);
536     }
537 }
538 
539 void
540 ata_fail_requests(device_t dev)
541 {
542     struct ata_channel *ch = device_get_softc(device_get_parent(dev));
543     struct ata_request *request, *tmp;
544     TAILQ_HEAD(, ata_request) fail_requests;
545     TAILQ_INIT(&fail_requests);
546 
547     /* grap all channel locks to avoid races */
548     spin_lock_wr(&ch->queue_mtx);
549     spin_lock_wr(&ch->state_mtx);
550 
551     /* do we have any running request to care about ? */
552     if ((request = ch->running) && (!dev || request->dev == dev)) {
553 	callout_stop(&request->callout);
554 	ch->running = NULL;
555 	request->result = ENXIO;
556 	TAILQ_INSERT_TAIL(&fail_requests, request, chain);
557     }
558 
559     /* fail all requests queued on this channel for device dev if !NULL */
560     TAILQ_FOREACH_MUTABLE(request, &ch->ata_queue, chain, tmp) {
561 	if (!dev || request->dev == dev) {
562 	    if (ch->transition == request)
563 		ch->transition = TAILQ_NEXT(request, chain);
564 	    TAILQ_REMOVE(&ch->ata_queue, request, chain);
565 	    request->result = ENXIO;
566 	    TAILQ_INSERT_TAIL(&fail_requests, request, chain);
567 	}
568     }
569 
570     spin_unlock_wr(&ch->state_mtx);
571     spin_unlock_wr(&ch->queue_mtx);
572 
573     /* finish up all requests collected above */
574     TAILQ_FOREACH_MUTABLE(request, &fail_requests, chain, tmp) {
575         TAILQ_REMOVE(&fail_requests, request, chain);
576         ata_finish(request);
577     }
578 }
579 
580 static u_int64_t
581 ata_get_lba(struct ata_request *request)
582 {
583     if (request->flags & ATA_R_ATAPI) {
584 	switch (request->u.atapi.ccb[0]) {
585 	case ATAPI_READ_BIG:
586 	case ATAPI_WRITE_BIG:
587 	case ATAPI_READ_CD:
588 	    return (request->u.atapi.ccb[5]) | (request->u.atapi.ccb[4]<<8) |
589 		   (request->u.atapi.ccb[3]<<16)|(request->u.atapi.ccb[2]<<24);
590 	case ATAPI_READ:
591 	case ATAPI_WRITE:
592 	    return (request->u.atapi.ccb[4]) | (request->u.atapi.ccb[3]<<8) |
593 		   (request->u.atapi.ccb[2]<<16);
594 	default:
595 	    return 0;
596 	}
597     }
598     else
599 	return request->u.ata.lba;
600 }
601 
602 /*
603  * This implements exactly bioqdisksort() in the DragonFly kernel.
604  * The short description is: Because megabytes and megabytes worth of
605  * writes can be queued there needs to be a read-prioritization mechanism
606  * or reads get completely starved out.
607  */
608 static void
609 ata_sort_queue(struct ata_channel *ch, struct ata_request *request)
610 {
611     if ((request->flags & ATA_R_WRITE) == 0) {
612 	if (ch->transition) {
613 	    /*
614 	     * Insert before the first write
615 	     */
616 	    TAILQ_INSERT_BEFORE(ch->transition, request, chain);
617 	    if (++ch->reorder >= bioq_reorder_minor_interval) {
618 		ch->reorder = 0;
619 		atawritereorder(ch);
620 	    }
621 	} else {
622 	    /*
623 	     * No writes queued (or ordering was forced),
624 	     * insert at tail.
625 	     */
626 	    TAILQ_INSERT_TAIL(&ch->ata_queue, request, chain);
627 	}
628     } else {
629 	/*
630 	 * Writes are always appended.  If no writes were previously
631 	 * queued or an ordered tail insertion occured the transition
632 	 * field will be NULL.
633 	 */
634 	TAILQ_INSERT_TAIL(&ch->ata_queue, request, chain);
635 	if (ch->transition == NULL)
636 		ch->transition = request;
637     }
638     if (request->composite) {
639 	ch->transition = NULL;
640 	ch->reorder = 0;
641     }
642 }
643 
644 /*
645  * Move the transition point to prevent reads from completely
646  * starving our writes.  This brings a number of writes into
647  * the fold every N reads.
648  */
649 static void
650 atawritereorder(struct ata_channel *ch)
651 {
652     struct ata_request *req;
653     u_int64_t next_offset;
654     size_t left = (size_t)bioq_reorder_minor_bytes;
655     size_t n;
656 
657     next_offset = ata_get_lba(ch->transition);
658     while ((req = ch->transition) != NULL &&
659 	   next_offset == ata_get_lba(req)) {
660 	n = req->u.ata.count;
661 	next_offset = ata_get_lba(req);
662 	ch->transition = TAILQ_NEXT(req, chain);
663 	if (left < n)
664 	    break;
665 	left -= n;
666     }
667 }
668 
669 char *
670 ata_cmd2str(struct ata_request *request)
671 {
672     static char buffer[20];
673 
674     if (request->flags & ATA_R_ATAPI) {
675 	switch (request->u.atapi.sense.key ?
676 		request->u.atapi.saved_cmd : request->u.atapi.ccb[0]) {
677 	case 0x00: return ("TEST_UNIT_READY");
678 	case 0x01: return ("REZERO");
679 	case 0x03: return ("REQUEST_SENSE");
680 	case 0x04: return ("FORMAT");
681 	case 0x08: return ("READ");
682 	case 0x0a: return ("WRITE");
683 	case 0x10: return ("WEOF");
684 	case 0x11: return ("SPACE");
685 	case 0x12: return ("INQUIRY");
686 	case 0x15: return ("MODE_SELECT");
687 	case 0x19: return ("ERASE");
688 	case 0x1a: return ("MODE_SENSE");
689 	case 0x1b: return ("START_STOP");
690 	case 0x1e: return ("PREVENT_ALLOW");
691 	case 0x23: return ("ATAPI_READ_FORMAT_CAPACITIES");
692 	case 0x25: return ("READ_CAPACITY");
693 	case 0x28: return ("READ_BIG");
694 	case 0x2a: return ("WRITE_BIG");
695 	case 0x2b: return ("LOCATE");
696 	case 0x34: return ("READ_POSITION");
697 	case 0x35: return ("SYNCHRONIZE_CACHE");
698 	case 0x3b: return ("WRITE_BUFFER");
699 	case 0x3c: return ("READ_BUFFER");
700 	case 0x42: return ("READ_SUBCHANNEL");
701 	case 0x43: return ("READ_TOC");
702 	case 0x45: return ("PLAY_10");
703 	case 0x47: return ("PLAY_MSF");
704 	case 0x48: return ("PLAY_TRACK");
705 	case 0x4b: return ("PAUSE");
706 	case 0x51: return ("READ_DISK_INFO");
707 	case 0x52: return ("READ_TRACK_INFO");
708 	case 0x53: return ("RESERVE_TRACK");
709 	case 0x54: return ("SEND_OPC_INFO");
710 	case 0x55: return ("MODE_SELECT_BIG");
711 	case 0x58: return ("REPAIR_TRACK");
712 	case 0x59: return ("READ_MASTER_CUE");
713 	case 0x5a: return ("MODE_SENSE_BIG");
714 	case 0x5b: return ("CLOSE_TRACK/SESSION");
715 	case 0x5c: return ("READ_BUFFER_CAPACITY");
716 	case 0x5d: return ("SEND_CUE_SHEET");
717         case 0x96: return ("READ_CAPACITY_16");
718 	case 0xa1: return ("BLANK_CMD");
719 	case 0xa3: return ("SEND_KEY");
720 	case 0xa4: return ("REPORT_KEY");
721 	case 0xa5: return ("PLAY_12");
722 	case 0xa6: return ("LOAD_UNLOAD");
723 	case 0xad: return ("READ_DVD_STRUCTURE");
724 	case 0xb4: return ("PLAY_CD");
725 	case 0xbb: return ("SET_SPEED");
726 	case 0xbd: return ("MECH_STATUS");
727 	case 0xbe: return ("READ_CD");
728 	case 0xff: return ("POLL_DSC");
729 	}
730     }
731     else {
732 	switch (request->u.ata.command) {
733 	case 0x00: return ("NOP");
734 	case 0x08: return ("DEVICE_RESET");
735 	case 0x20: return ("READ");
736 	case 0x24: return ("READ48");
737 	case 0x25: return ("READ_DMA48");
738 	case 0x26: return ("READ_DMA_QUEUED48");
739 	case 0x29: return ("READ_MUL48");
740 	case 0x30: return ("WRITE");
741 	case 0x34: return ("WRITE48");
742 	case 0x35: return ("WRITE_DMA48");
743 	case 0x36: return ("WRITE_DMA_QUEUED48");
744 	case 0x39: return ("WRITE_MUL48");
745 	case 0x70: return ("SEEK");
746 	case 0xa0: return ("PACKET_CMD");
747 	case 0xa1: return ("ATAPI_IDENTIFY");
748 	case 0xa2: return ("SERVICE");
749 	case 0xb0: return ("SMART");
750 	case 0xc0: return ("CFA ERASE");
751 	case 0xc4: return ("READ_MUL");
752 	case 0xc5: return ("WRITE_MUL");
753 	case 0xc6: return ("SET_MULTI");
754 	case 0xc7: return ("READ_DMA_QUEUED");
755 	case 0xc8: return ("READ_DMA");
756 	case 0xca: return ("WRITE_DMA");
757 	case 0xcc: return ("WRITE_DMA_QUEUED");
758 	case 0xe6: return ("SLEEP");
759 	case 0xe7: return ("FLUSHCACHE");
760 	case 0xea: return ("FLUSHCACHE48");
761 	case 0xec: return ("ATA_IDENTIFY");
762 	case 0xef:
763 	    switch (request->u.ata.feature) {
764 	    case 0x03: return ("SETFEATURES SET TRANSFER MODE");
765 	    case 0x02: return ("SETFEATURES ENABLE WCACHE");
766 	    case 0x82: return ("SETFEATURES DISABLE WCACHE");
767 	    case 0xaa: return ("SETFEATURES ENABLE RCACHE");
768 	    case 0x55: return ("SETFEATURES DISABLE RCACHE");
769 	    }
770 	    ksprintf(buffer, "SETFEATURES 0x%02x", request->u.ata.feature);
771 	    return buffer;
772 	}
773     }
774     ksprintf(buffer, "unknown CMD (0x%02x)", request->u.ata.command);
775     return buffer;
776 }
777 
778 static char *
779 ata_skey2str(u_int8_t skey)
780 {
781     switch (skey) {
782     case 0x00: return ("NO SENSE");
783     case 0x01: return ("RECOVERED ERROR");
784     case 0x02: return ("NOT READY");
785     case 0x03: return ("MEDIUM ERROR");
786     case 0x04: return ("HARDWARE ERROR");
787     case 0x05: return ("ILLEGAL REQUEST");
788     case 0x06: return ("UNIT ATTENTION");
789     case 0x07: return ("DATA PROTECT");
790     case 0x08: return ("BLANK CHECK");
791     case 0x09: return ("VENDOR SPECIFIC");
792     case 0x0a: return ("COPY ABORTED");
793     case 0x0b: return ("ABORTED COMMAND");
794     case 0x0c: return ("EQUAL");
795     case 0x0d: return ("VOLUME OVERFLOW");
796     case 0x0e: return ("MISCOMPARE");
797     case 0x0f: return ("RESERVED");
798     default: return("UNKNOWN");
799     }
800 }
801