Eliminate some uses of T2
[qemu/malc.git] / hw / scsi-disk.c
blob44462d43519f0858f21663c4dab309f3925b798b
1 /*
2 * SCSI Device emulation
4 * Copyright (c) 2006 CodeSourcery.
5 * Based on code by Fabrice Bellard
7 * Written by Paul Brook
9 * This code is licenced under the LGPL.
11 * Note that this file only handles the SCSI architecture model and device
12 * commands. Emulation of interface/link layer protocols is handled by
13 * the host adapter emulator.
16 //#define DEBUG_SCSI
18 #ifdef DEBUG_SCSI
19 #define DPRINTF(fmt, args...) \
20 do { printf("scsi-disk: " fmt , ##args); } while (0)
21 #else
22 #define DPRINTF(fmt, args...) do {} while(0)
23 #endif
25 #define BADF(fmt, args...) \
26 do { fprintf(stderr, "scsi-disk: " fmt , ##args); } while (0)
28 #include "qemu-common.h"
29 #include "block.h"
30 #include "scsi-disk.h"
32 #define SENSE_NO_SENSE 0
33 #define SENSE_NOT_READY 2
34 #define SENSE_HARDWARE_ERROR 4
35 #define SENSE_ILLEGAL_REQUEST 5
37 #define SCSI_DMA_BUF_SIZE 65536
39 typedef struct SCSIRequest {
40 SCSIDeviceState *dev;
41 uint32_t tag;
42 /* ??? We should probably keep track of whether the data trasfer is
43 a read or a write. Currently we rely on the host getting it right. */
44 /* Both sector and sector_count are in terms of qemu 512 byte blocks. */
45 int sector;
46 int sector_count;
47 /* The amounnt of data in the buffer. */
48 int buf_len;
49 uint8_t *dma_buf;
50 BlockDriverAIOCB *aiocb;
51 struct SCSIRequest *next;
52 } SCSIRequest;
54 struct SCSIDeviceState
56 BlockDriverState *bdrv;
57 SCSIRequest *requests;
58 /* The qemu block layer uses a fixed 512 byte sector size.
59 This is the number of 512 byte blocks in a single scsi sector. */
60 int cluster_size;
61 int sense;
62 int tcq;
63 /* Completion functions may be called from either scsi_{read,write}_data
64 or from the AIO completion routines. */
65 scsi_completionfn completion;
66 void *opaque;
69 /* Global pool of SCSIRequest structures. */
70 static SCSIRequest *free_requests = NULL;
72 static SCSIRequest *scsi_new_request(SCSIDeviceState *s, uint32_t tag)
74 SCSIRequest *r;
76 if (free_requests) {
77 r = free_requests;
78 free_requests = r->next;
79 } else {
80 r = qemu_malloc(sizeof(SCSIRequest));
81 r->dma_buf = qemu_memalign(512, SCSI_DMA_BUF_SIZE);
83 r->dev = s;
84 r->tag = tag;
85 r->sector_count = 0;
86 r->buf_len = 0;
87 r->aiocb = NULL;
89 r->next = s->requests;
90 s->requests = r;
91 return r;
94 static void scsi_remove_request(SCSIRequest *r)
96 SCSIRequest *last;
97 SCSIDeviceState *s = r->dev;
99 if (s->requests == r) {
100 s->requests = r->next;
101 } else {
102 last = s->requests;
103 while (last && last->next != r)
104 last = last->next;
105 if (last) {
106 last->next = r->next;
107 } else {
108 BADF("Orphaned request\n");
111 r->next = free_requests;
112 free_requests = r;
115 static SCSIRequest *scsi_find_request(SCSIDeviceState *s, uint32_t tag)
117 SCSIRequest *r;
119 r = s->requests;
120 while (r && r->tag != tag)
121 r = r->next;
123 return r;
126 /* Helper function for command completion. */
127 static void scsi_command_complete(SCSIRequest *r, int sense)
129 SCSIDeviceState *s = r->dev;
130 uint32_t tag;
131 DPRINTF("Command complete tag=0x%x sense=%d\n", r->tag, sense);
132 s->sense = sense;
133 tag = r->tag;
134 scsi_remove_request(r);
135 s->completion(s->opaque, SCSI_REASON_DONE, tag, sense);
138 /* Cancel a pending data transfer. */
139 static void scsi_cancel_io(SCSIDevice *d, uint32_t tag)
141 SCSIDeviceState *s = d->state;
142 SCSIRequest *r;
143 DPRINTF("Cancel tag=0x%x\n", tag);
144 r = scsi_find_request(s, tag);
145 if (r) {
146 if (r->aiocb)
147 bdrv_aio_cancel(r->aiocb);
148 r->aiocb = NULL;
149 scsi_remove_request(r);
153 static void scsi_read_complete(void * opaque, int ret)
155 SCSIRequest *r = (SCSIRequest *)opaque;
156 SCSIDeviceState *s = r->dev;
158 if (ret) {
159 DPRINTF("IO error\n");
160 scsi_command_complete(r, SENSE_HARDWARE_ERROR);
161 return;
163 DPRINTF("Data ready tag=0x%x len=%d\n", r->tag, r->buf_len);
165 s->completion(s->opaque, SCSI_REASON_DATA, r->tag, r->buf_len);
168 /* Read more data from scsi device into buffer. */
169 static void scsi_read_data(SCSIDevice *d, uint32_t tag)
171 SCSIDeviceState *s = d->state;
172 SCSIRequest *r;
173 uint32_t n;
175 r = scsi_find_request(s, tag);
176 if (!r) {
177 BADF("Bad read tag 0x%x\n", tag);
178 /* ??? This is the wrong error. */
179 scsi_command_complete(r, SENSE_HARDWARE_ERROR);
180 return;
182 if (r->sector_count == (uint32_t)-1) {
183 DPRINTF("Read buf_len=%d\n", r->buf_len);
184 r->sector_count = 0;
185 s->completion(s->opaque, SCSI_REASON_DATA, r->tag, r->buf_len);
186 return;
188 DPRINTF("Read sector_count=%d\n", r->sector_count);
189 if (r->sector_count == 0) {
190 scsi_command_complete(r, SENSE_NO_SENSE);
191 return;
194 n = r->sector_count;
195 if (n > SCSI_DMA_BUF_SIZE / 512)
196 n = SCSI_DMA_BUF_SIZE / 512;
198 r->buf_len = n * 512;
199 r->aiocb = bdrv_aio_read(s->bdrv, r->sector, r->dma_buf, n,
200 scsi_read_complete, r);
201 if (r->aiocb == NULL)
202 scsi_command_complete(r, SENSE_HARDWARE_ERROR);
203 r->sector += n;
204 r->sector_count -= n;
207 static void scsi_write_complete(void * opaque, int ret)
209 SCSIRequest *r = (SCSIRequest *)opaque;
210 SCSIDeviceState *s = r->dev;
211 uint32_t len;
213 if (ret) {
214 fprintf(stderr, "scsi-disc: IO write error\n");
215 exit(1);
218 r->aiocb = NULL;
219 if (r->sector_count == 0) {
220 scsi_command_complete(r, SENSE_NO_SENSE);
221 } else {
222 len = r->sector_count * 512;
223 if (len > SCSI_DMA_BUF_SIZE) {
224 len = SCSI_DMA_BUF_SIZE;
226 r->buf_len = len;
227 DPRINTF("Write complete tag=0x%x more=%d\n", r->tag, len);
228 s->completion(s->opaque, SCSI_REASON_DATA, r->tag, len);
232 /* Write data to a scsi device. Returns nonzero on failure.
233 The transfer may complete asynchronously. */
234 static int scsi_write_data(SCSIDevice *d, uint32_t tag)
236 SCSIDeviceState *s = d->state;
237 SCSIRequest *r;
238 uint32_t n;
240 DPRINTF("Write data tag=0x%x\n", tag);
241 r = scsi_find_request(s, tag);
242 if (!r) {
243 BADF("Bad write tag 0x%x\n", tag);
244 scsi_command_complete(r, SENSE_HARDWARE_ERROR);
245 return 1;
247 if (r->aiocb)
248 BADF("Data transfer already in progress\n");
249 n = r->buf_len / 512;
250 if (n) {
251 r->aiocb = bdrv_aio_write(s->bdrv, r->sector, r->dma_buf, n,
252 scsi_write_complete, r);
253 if (r->aiocb == NULL)
254 scsi_command_complete(r, SENSE_HARDWARE_ERROR);
255 r->sector += n;
256 r->sector_count -= n;
257 } else {
258 /* Invoke completion routine to fetch data from host. */
259 scsi_write_complete(r, 0);
262 return 0;
265 /* Return a pointer to the data buffer. */
266 static uint8_t *scsi_get_buf(SCSIDevice *d, uint32_t tag)
268 SCSIDeviceState *s = d->state;
269 SCSIRequest *r;
271 r = scsi_find_request(s, tag);
272 if (!r) {
273 BADF("Bad buffer tag 0x%x\n", tag);
274 return NULL;
276 return r->dma_buf;
279 /* Execute a scsi command. Returns the length of the data expected by the
280 command. This will be Positive for data transfers from the device
281 (eg. disk reads), negative for transfers to the device (eg. disk writes),
282 and zero if the command does not transfer any data. */
284 static int32_t scsi_send_command(SCSIDevice *d, uint32_t tag,
285 uint8_t *buf, int lun)
287 SCSIDeviceState *s = d->state;
288 uint64_t nb_sectors;
289 uint32_t lba;
290 uint32_t len;
291 int cmdlen;
292 int is_write;
293 uint8_t command;
294 uint8_t *outbuf;
295 SCSIRequest *r;
297 command = buf[0];
298 r = scsi_find_request(s, tag);
299 if (r) {
300 BADF("Tag 0x%x already in use\n", tag);
301 scsi_cancel_io(d, tag);
303 /* ??? Tags are not unique for different luns. We only implement a
304 single lun, so this should not matter. */
305 r = scsi_new_request(s, tag);
306 outbuf = r->dma_buf;
307 is_write = 0;
308 DPRINTF("Command: lun=%d tag=0x%x data=0x%02x", lun, tag, buf[0]);
309 switch (command >> 5) {
310 case 0:
311 lba = buf[3] | (buf[2] << 8) | ((buf[1] & 0x1f) << 16);
312 len = buf[4];
313 cmdlen = 6;
314 break;
315 case 1:
316 case 2:
317 lba = buf[5] | (buf[4] << 8) | (buf[3] << 16) | (buf[2] << 24);
318 len = buf[8] | (buf[7] << 8);
319 cmdlen = 10;
320 break;
321 case 4:
322 lba = buf[5] | (buf[4] << 8) | (buf[3] << 16) | (buf[2] << 24);
323 len = buf[13] | (buf[12] << 8) | (buf[11] << 16) | (buf[10] << 24);
324 cmdlen = 16;
325 break;
326 case 5:
327 lba = buf[5] | (buf[4] << 8) | (buf[3] << 16) | (buf[2] << 24);
328 len = buf[9] | (buf[8] << 8) | (buf[7] << 16) | (buf[6] << 24);
329 cmdlen = 12;
330 break;
331 default:
332 BADF("Unsupported command length, command %x\n", command);
333 goto fail;
335 #ifdef DEBUG_SCSI
337 int i;
338 for (i = 1; i < cmdlen; i++) {
339 printf(" 0x%02x", buf[i]);
341 printf("\n");
343 #endif
344 if (lun || buf[1] >> 5) {
345 /* Only LUN 0 supported. */
346 DPRINTF("Unimplemented LUN %d\n", lun ? lun : buf[1] >> 5);
347 goto fail;
349 switch (command) {
350 case 0x0:
351 DPRINTF("Test Unit Ready\n");
352 break;
353 case 0x03:
354 DPRINTF("Request Sense (len %d)\n", len);
355 if (len < 4)
356 goto fail;
357 memset(outbuf, 0, 4);
358 outbuf[0] = 0xf0;
359 outbuf[1] = 0;
360 outbuf[2] = s->sense;
361 r->buf_len = 4;
362 break;
363 case 0x12:
364 DPRINTF("Inquiry (len %d)\n", len);
365 if (buf[1] & 0x2) {
366 /* Command support data - optional, not implemented */
367 BADF("optional INQUIRY command support request not implemented\n");
368 goto fail;
370 else if (buf[1] & 0x1) {
371 /* Vital product data */
372 uint8_t page_code = buf[2];
373 if (len < 4) {
374 BADF("Error: Inquiry (EVPD[%02X]) buffer size %d is "
375 "less than 4\n", page_code, len);
376 goto fail;
379 switch (page_code) {
380 case 0x00:
382 /* Supported page codes, mandatory */
383 DPRINTF("Inquiry EVPD[Supported pages] "
384 "buffer size %d\n", len);
386 r->buf_len = 0;
388 if (bdrv_get_type_hint(s->bdrv) == BDRV_TYPE_CDROM) {
389 outbuf[r->buf_len++] = 5;
390 } else {
391 outbuf[r->buf_len++] = 0;
394 outbuf[r->buf_len++] = 0x00; // this page
395 outbuf[r->buf_len++] = 0x00;
396 outbuf[r->buf_len++] = 3; // number of pages
397 outbuf[r->buf_len++] = 0x00; // list of supported pages (this page)
398 outbuf[r->buf_len++] = 0x80; // unit serial number
399 outbuf[r->buf_len++] = 0x83; // device identification
401 break;
402 case 0x80:
404 /* Device serial number, optional */
405 if (len < 4) {
406 BADF("Error: EVPD[Serial number] Inquiry buffer "
407 "size %d too small, %d needed\n", len, 4);
408 goto fail;
411 DPRINTF("Inquiry EVPD[Serial number] buffer size %d\n", len);
413 r->buf_len = 0;
415 /* Supported page codes */
416 if (bdrv_get_type_hint(s->bdrv) == BDRV_TYPE_CDROM) {
417 outbuf[r->buf_len++] = 5;
418 } else {
419 outbuf[r->buf_len++] = 0;
422 outbuf[r->buf_len++] = 0x80; // this page
423 outbuf[r->buf_len++] = 0x00;
424 outbuf[r->buf_len++] = 0x01; // 1 byte data follow
426 outbuf[r->buf_len++] = '0'; // 1 byte data follow
429 break;
430 case 0x83:
432 /* Device identification page, mandatory */
433 int max_len = 255 - 8;
434 int id_len = strlen(bdrv_get_device_name(s->bdrv));
435 if (id_len > max_len)
436 id_len = max_len;
438 DPRINTF("Inquiry EVPD[Device identification] "
439 "buffer size %d\n", len);
440 r->buf_len = 0;
441 if (bdrv_get_type_hint(s->bdrv) == BDRV_TYPE_CDROM) {
442 outbuf[r->buf_len++] = 5;
443 } else {
444 outbuf[r->buf_len++] = 0;
447 outbuf[r->buf_len++] = 0x83; // this page
448 outbuf[r->buf_len++] = 0x00;
449 outbuf[r->buf_len++] = 3 + id_len;
451 outbuf[r->buf_len++] = 0x2; // ASCII
452 outbuf[r->buf_len++] = 0; // not officially assigned
453 outbuf[r->buf_len++] = 0; // reserved
454 outbuf[r->buf_len++] = id_len; // length of data following
456 memcpy(&outbuf[r->buf_len],
457 bdrv_get_device_name(s->bdrv), id_len);
458 r->buf_len += id_len;
460 break;
461 default:
462 BADF("Error: unsupported Inquiry (EVPD[%02X]) "
463 "buffer size %d\n", page_code, len);
464 goto fail;
466 /* done with EVPD */
467 break;
469 else {
470 /* Standard INQUIRY data */
471 if (buf[2] != 0) {
472 BADF("Error: Inquiry (STANDARD) page or code "
473 "is non-zero [%02X]\n", buf[2]);
474 goto fail;
477 /* PAGE CODE == 0 */
478 if (len < 5) {
479 BADF("Error: Inquiry (STANDARD) buffer size %d "
480 "is less than 5\n", len);
481 goto fail;
484 if (len < 36) {
485 BADF("Error: Inquiry (STANDARD) buffer size %d "
486 "is less than 36 (TODO: only 5 required)\n", len);
489 memset(outbuf, 0, 36);
490 if (bdrv_get_type_hint(s->bdrv) == BDRV_TYPE_CDROM) {
491 outbuf[0] = 5;
492 outbuf[1] = 0x80;
493 memcpy(&outbuf[16], "QEMU CD-ROM ", 16);
494 } else {
495 outbuf[0] = 0;
496 memcpy(&outbuf[16], "QEMU HARDDISK ", 16);
498 memcpy(&outbuf[8], "QEMU ", 8);
499 memcpy(&outbuf[32], QEMU_VERSION, 4);
500 /* Identify device as SCSI-3 rev 1.
501 Some later commands are also implemented. */
502 outbuf[2] = 3;
503 outbuf[3] = 2; /* Format 2 */
504 outbuf[4] = 31;
505 /* Sync data transfer and TCQ. */
506 outbuf[7] = 0x10 | (s->tcq ? 0x02 : 0);
507 r->buf_len = 36;
508 break;
509 case 0x16:
510 DPRINTF("Reserve(6)\n");
511 if (buf[1] & 1)
512 goto fail;
513 break;
514 case 0x17:
515 DPRINTF("Release(6)\n");
516 if (buf[1] & 1)
517 goto fail;
518 break;
519 case 0x1a:
520 case 0x5a:
522 uint8_t *p;
523 int page;
525 page = buf[2] & 0x3f;
526 DPRINTF("Mode Sense (page %d, len %d)\n", page, len);
527 p = outbuf;
528 memset(p, 0, 4);
529 outbuf[1] = 0; /* Default media type. */
530 outbuf[3] = 0; /* Block descriptor length. */
531 if (bdrv_get_type_hint(s->bdrv) == BDRV_TYPE_CDROM) {
532 outbuf[2] = 0x80; /* Readonly. */
534 p += 4;
535 if ((page == 8 || page == 0x3f)) {
536 /* Caching page. */
537 memset(p,0,20);
538 p[0] = 8;
539 p[1] = 0x12;
540 p[2] = 4; /* WCE */
541 p += 20;
543 if ((page == 0x3f || page == 0x2a)
544 && (bdrv_get_type_hint(s->bdrv) == BDRV_TYPE_CDROM)) {
545 /* CD Capabilities and Mechanical Status page. */
546 p[0] = 0x2a;
547 p[1] = 0x14;
548 p[2] = 3; // CD-R & CD-RW read
549 p[3] = 0; // Writing not supported
550 p[4] = 0x7f; /* Audio, composite, digital out,
551 mode 2 form 1&2, multi session */
552 p[5] = 0xff; /* CD DA, DA accurate, RW supported,
553 RW corrected, C2 errors, ISRC,
554 UPC, Bar code */
555 p[6] = 0x2d | (bdrv_is_locked(s->bdrv)? 2 : 0);
556 /* Locking supported, jumper present, eject, tray */
557 p[7] = 0; /* no volume & mute control, no
558 changer */
559 p[8] = (50 * 176) >> 8; // 50x read speed
560 p[9] = (50 * 176) & 0xff;
561 p[10] = 0 >> 8; // No volume
562 p[11] = 0 & 0xff;
563 p[12] = 2048 >> 8; // 2M buffer
564 p[13] = 2048 & 0xff;
565 p[14] = (16 * 176) >> 8; // 16x read speed current
566 p[15] = (16 * 176) & 0xff;
567 p[18] = (16 * 176) >> 8; // 16x write speed
568 p[19] = (16 * 176) & 0xff;
569 p[20] = (16 * 176) >> 8; // 16x write speed current
570 p[21] = (16 * 176) & 0xff;
571 p += 22;
573 r->buf_len = p - outbuf;
574 outbuf[0] = r->buf_len - 4;
575 if (r->buf_len > len)
576 r->buf_len = len;
578 break;
579 case 0x1b:
580 DPRINTF("Start Stop Unit\n");
581 break;
582 case 0x1e:
583 DPRINTF("Prevent Allow Medium Removal (prevent = %d)\n", buf[4] & 3);
584 bdrv_set_locked(s->bdrv, buf[4] & 1);
585 break;
586 case 0x25:
587 DPRINTF("Read Capacity\n");
588 /* The normal LEN field for this command is zero. */
589 memset(outbuf, 0, 8);
590 bdrv_get_geometry(s->bdrv, &nb_sectors);
591 /* Returned value is the address of the last sector. */
592 if (nb_sectors) {
593 nb_sectors--;
594 outbuf[0] = (nb_sectors >> 24) & 0xff;
595 outbuf[1] = (nb_sectors >> 16) & 0xff;
596 outbuf[2] = (nb_sectors >> 8) & 0xff;
597 outbuf[3] = nb_sectors & 0xff;
598 outbuf[4] = 0;
599 outbuf[5] = 0;
600 outbuf[6] = s->cluster_size * 2;
601 outbuf[7] = 0;
602 r->buf_len = 8;
603 } else {
604 scsi_command_complete(r, SENSE_NOT_READY);
605 return 0;
607 break;
608 case 0x08:
609 case 0x28:
610 DPRINTF("Read (sector %d, count %d)\n", lba, len);
611 r->sector = lba * s->cluster_size;
612 r->sector_count = len * s->cluster_size;
613 break;
614 case 0x0a:
615 case 0x2a:
616 DPRINTF("Write (sector %d, count %d)\n", lba, len);
617 r->sector = lba * s->cluster_size;
618 r->sector_count = len * s->cluster_size;
619 is_write = 1;
620 break;
621 case 0x35:
622 DPRINTF("Synchronise cache (sector %d, count %d)\n", lba, len);
623 bdrv_flush(s->bdrv);
624 break;
625 case 0x43:
627 int start_track, format, msf, toclen;
629 msf = buf[1] & 2;
630 format = buf[2] & 0xf;
631 start_track = buf[6];
632 bdrv_get_geometry(s->bdrv, &nb_sectors);
633 DPRINTF("Read TOC (track %d format %d msf %d)\n", start_track, format, msf >> 1);
634 switch(format) {
635 case 0:
636 toclen = cdrom_read_toc(nb_sectors, outbuf, msf, start_track);
637 break;
638 case 1:
639 /* multi session : only a single session defined */
640 toclen = 12;
641 memset(outbuf, 0, 12);
642 outbuf[1] = 0x0a;
643 outbuf[2] = 0x01;
644 outbuf[3] = 0x01;
645 break;
646 case 2:
647 toclen = cdrom_read_toc_raw(nb_sectors, outbuf, msf, start_track);
648 break;
649 default:
650 goto error_cmd;
652 if (toclen > 0) {
653 if (len > toclen)
654 len = toclen;
655 r->buf_len = len;
656 break;
658 error_cmd:
659 DPRINTF("Read TOC error\n");
660 goto fail;
662 case 0x46:
663 DPRINTF("Get Configuration (rt %d, maxlen %d)\n", buf[1] & 3, len);
664 memset(outbuf, 0, 8);
665 /* ??? This shoud probably return much more information. For now
666 just return the basic header indicating the CD-ROM profile. */
667 outbuf[7] = 8; // CD-ROM
668 r->buf_len = 8;
669 break;
670 case 0x56:
671 DPRINTF("Reserve(10)\n");
672 if (buf[1] & 3)
673 goto fail;
674 break;
675 case 0x57:
676 DPRINTF("Release(10)\n");
677 if (buf[1] & 3)
678 goto fail;
679 break;
680 case 0xa0:
681 DPRINTF("Report LUNs (len %d)\n", len);
682 if (len < 16)
683 goto fail;
684 memset(outbuf, 0, 16);
685 outbuf[3] = 8;
686 r->buf_len = 16;
687 break;
688 default:
689 DPRINTF("Unknown SCSI command (%2.2x)\n", buf[0]);
690 fail:
691 scsi_command_complete(r, SENSE_ILLEGAL_REQUEST);
692 return 0;
694 if (r->sector_count == 0 && r->buf_len == 0) {
695 scsi_command_complete(r, SENSE_NO_SENSE);
697 len = r->sector_count * 512 + r->buf_len;
698 if (is_write) {
699 return -len;
700 } else {
701 if (!r->sector_count)
702 r->sector_count = -1;
703 return len;
707 static void scsi_destroy(SCSIDevice *d)
709 qemu_free(d->state);
710 qemu_free(d);
713 SCSIDevice *scsi_disk_init(BlockDriverState *bdrv, int tcq,
714 scsi_completionfn completion, void *opaque)
716 SCSIDevice *d;
717 SCSIDeviceState *s;
719 s = (SCSIDeviceState *)qemu_mallocz(sizeof(SCSIDeviceState));
720 s->bdrv = bdrv;
721 s->tcq = tcq;
722 s->completion = completion;
723 s->opaque = opaque;
724 if (bdrv_get_type_hint(s->bdrv) == BDRV_TYPE_CDROM) {
725 s->cluster_size = 4;
726 } else {
727 s->cluster_size = 1;
730 d = (SCSIDevice *)qemu_mallocz(sizeof(SCSIDevice));
731 d->state = s;
732 d->destroy = scsi_destroy;
733 d->send_command = scsi_send_command;
734 d->read_data = scsi_read_data;
735 d->write_data = scsi_write_data;
736 d->cancel_io = scsi_cancel_io;
737 d->get_buf = scsi_get_buf;
739 return d;