xref: /qemu/hw/scsi/esp.c (revision c5d7df28ea9f83b73608afb0ed6fb75773ebe7ca)
1 /*
2  * QEMU ESP/NCR53C9x emulation
3  *
4  * Copyright (c) 2005-2006 Fabrice Bellard
5  * Copyright (c) 2012 Herve Poussineau
6  *
7  * Permission is hereby granted, free of charge, to any person obtaining a copy
8  * of this software and associated documentation files (the "Software"), to deal
9  * in the Software without restriction, including without limitation the rights
10  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
11  * copies of the Software, and to permit persons to whom the Software is
12  * furnished to do so, subject to the following conditions:
13  *
14  * The above copyright notice and this permission notice shall be included in
15  * all copies or substantial portions of the Software.
16  *
17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
18  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
20  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
21  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
22  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
23  * THE SOFTWARE.
24  */
25 
26 #include "qemu/osdep.h"
27 #include "hw/sysbus.h"
28 #include "migration/vmstate.h"
29 #include "hw/irq.h"
30 #include "hw/scsi/esp.h"
31 #include "trace.h"
32 #include "qemu/log.h"
33 #include "qemu/module.h"
34 
35 /*
36  * On Sparc32, this is the ESP (NCR53C90) part of chip STP2000 (Master I/O),
37  * also produced as NCR89C100. See
38  * http://www.ibiblio.org/pub/historic-linux/early-ports/Sparc/NCR/NCR89C100.txt
39  * and
40  * http://www.ibiblio.org/pub/historic-linux/early-ports/Sparc/NCR/NCR53C9X.txt
41  *
42  * On Macintosh Quadra it is a NCR53C96.
43  */
44 
45 static void esp_raise_irq(ESPState *s)
46 {
47     if (!(s->rregs[ESP_RSTAT] & STAT_INT)) {
48         s->rregs[ESP_RSTAT] |= STAT_INT;
49         qemu_irq_raise(s->irq);
50         trace_esp_raise_irq();
51     }
52 }
53 
54 static void esp_lower_irq(ESPState *s)
55 {
56     if (s->rregs[ESP_RSTAT] & STAT_INT) {
57         s->rregs[ESP_RSTAT] &= ~STAT_INT;
58         qemu_irq_lower(s->irq);
59         trace_esp_lower_irq();
60     }
61 }
62 
63 static void esp_raise_drq(ESPState *s)
64 {
65     qemu_irq_raise(s->irq_data);
66     trace_esp_raise_drq();
67 }
68 
69 static void esp_lower_drq(ESPState *s)
70 {
71     qemu_irq_lower(s->irq_data);
72     trace_esp_lower_drq();
73 }
74 
75 void esp_dma_enable(ESPState *s, int irq, int level)
76 {
77     if (level) {
78         s->dma_enabled = 1;
79         trace_esp_dma_enable();
80         if (s->dma_cb) {
81             s->dma_cb(s);
82             s->dma_cb = NULL;
83         }
84     } else {
85         trace_esp_dma_disable();
86         s->dma_enabled = 0;
87     }
88 }
89 
90 void esp_request_cancelled(SCSIRequest *req)
91 {
92     ESPState *s = req->hba_private;
93 
94     if (req == s->current_req) {
95         scsi_req_unref(s->current_req);
96         s->current_req = NULL;
97         s->current_dev = NULL;
98         s->async_len = 0;
99     }
100 }
101 
102 static void esp_fifo_push(Fifo8 *fifo, uint8_t val)
103 {
104     if (fifo8_num_used(fifo) == fifo->capacity) {
105         trace_esp_error_fifo_overrun();
106         return;
107     }
108 
109     fifo8_push(fifo, val);
110 }
111 
112 static uint8_t esp_fifo_pop(Fifo8 *fifo)
113 {
114     if (fifo8_is_empty(fifo)) {
115         return 0;
116     }
117 
118     return fifo8_pop(fifo);
119 }
120 
121 static uint32_t esp_fifo_pop_buf(Fifo8 *fifo, uint8_t *dest, int maxlen)
122 {
123     const uint8_t *buf;
124     uint32_t n, n2;
125     int len;
126 
127     if (maxlen == 0) {
128         return 0;
129     }
130 
131     len = maxlen;
132     buf = fifo8_pop_buf(fifo, len, &n);
133     if (dest) {
134         memcpy(dest, buf, n);
135     }
136 
137     /* Add FIFO wraparound if needed */
138     len -= n;
139     len = MIN(len, fifo8_num_used(fifo));
140     if (len) {
141         buf = fifo8_pop_buf(fifo, len, &n2);
142         if (dest) {
143             memcpy(&dest[n], buf, n2);
144         }
145         n += n2;
146     }
147 
148     return n;
149 }
150 
151 static uint32_t esp_get_tc(ESPState *s)
152 {
153     uint32_t dmalen;
154 
155     dmalen = s->rregs[ESP_TCLO];
156     dmalen |= s->rregs[ESP_TCMID] << 8;
157     dmalen |= s->rregs[ESP_TCHI] << 16;
158 
159     return dmalen;
160 }
161 
162 static void esp_set_tc(ESPState *s, uint32_t dmalen)
163 {
164     uint32_t old_tc = esp_get_tc(s);
165 
166     s->rregs[ESP_TCLO] = dmalen;
167     s->rregs[ESP_TCMID] = dmalen >> 8;
168     s->rregs[ESP_TCHI] = dmalen >> 16;
169 
170     if (old_tc && dmalen == 0) {
171         s->rregs[ESP_RSTAT] |= STAT_TC;
172     }
173 }
174 
175 static uint32_t esp_get_stc(ESPState *s)
176 {
177     uint32_t dmalen;
178 
179     dmalen = s->wregs[ESP_TCLO];
180     dmalen |= s->wregs[ESP_TCMID] << 8;
181     dmalen |= s->wregs[ESP_TCHI] << 16;
182 
183     return dmalen;
184 }
185 
186 static uint8_t esp_pdma_read(ESPState *s)
187 {
188     uint8_t val;
189 
190     if (s->do_cmd) {
191         val = esp_fifo_pop(&s->cmdfifo);
192     } else {
193         val = esp_fifo_pop(&s->fifo);
194     }
195 
196     return val;
197 }
198 
199 static void esp_pdma_write(ESPState *s, uint8_t val)
200 {
201     uint32_t dmalen = esp_get_tc(s);
202 
203     if (dmalen == 0) {
204         return;
205     }
206 
207     if (s->do_cmd) {
208         esp_fifo_push(&s->cmdfifo, val);
209     } else {
210         esp_fifo_push(&s->fifo, val);
211     }
212 
213     dmalen--;
214     esp_set_tc(s, dmalen);
215 }
216 
217 static void esp_set_pdma_cb(ESPState *s, enum pdma_cb cb)
218 {
219     s->pdma_cb = cb;
220 }
221 
222 static int esp_select(ESPState *s)
223 {
224     int target;
225 
226     target = s->wregs[ESP_WBUSID] & BUSID_DID;
227 
228     s->ti_size = 0;
229 
230     if (s->current_req) {
231         /* Started a new command before the old one finished. Cancel it. */
232         scsi_req_cancel(s->current_req);
233     }
234 
235     s->current_dev = scsi_device_find(&s->bus, 0, target, 0);
236     if (!s->current_dev) {
237         /* No such drive */
238         s->rregs[ESP_RSTAT] = 0;
239         s->rregs[ESP_RINTR] = INTR_DC;
240         s->rregs[ESP_RSEQ] = SEQ_0;
241         esp_raise_irq(s);
242         return -1;
243     }
244 
245     /*
246      * Note that we deliberately don't raise the IRQ here: this will be done
247      * either in do_command_phase() for DATA OUT transfers or by the deferred
248      * IRQ mechanism in esp_transfer_data() for DATA IN transfers
249      */
250     s->rregs[ESP_RINTR] |= INTR_FC;
251     s->rregs[ESP_RSEQ] = SEQ_CD;
252     return 0;
253 }
254 
255 static uint32_t get_cmd(ESPState *s, uint32_t maxlen)
256 {
257     uint8_t buf[ESP_CMDFIFO_SZ];
258     uint32_t dmalen, n;
259     int target;
260 
261     target = s->wregs[ESP_WBUSID] & BUSID_DID;
262     if (s->dma) {
263         dmalen = MIN(esp_get_tc(s), maxlen);
264         if (dmalen == 0) {
265             return 0;
266         }
267         if (s->dma_memory_read) {
268             s->dma_memory_read(s->dma_opaque, buf, dmalen);
269             dmalen = MIN(fifo8_num_free(&s->cmdfifo), dmalen);
270             fifo8_push_all(&s->cmdfifo, buf, dmalen);
271         } else {
272             return 0;
273         }
274     } else {
275         dmalen = MIN(fifo8_num_used(&s->fifo), maxlen);
276         if (dmalen == 0) {
277             return 0;
278         }
279         n = esp_fifo_pop_buf(&s->fifo, buf, dmalen);
280         n = MIN(fifo8_num_free(&s->cmdfifo), n);
281         fifo8_push_all(&s->cmdfifo, buf, n);
282     }
283     trace_esp_get_cmd(dmalen, target);
284 
285     return dmalen;
286 }
287 
288 static void do_command_phase(ESPState *s)
289 {
290     uint32_t cmdlen;
291     int32_t datalen;
292     SCSIDevice *current_lun;
293     uint8_t buf[ESP_CMDFIFO_SZ];
294 
295     trace_esp_do_command_phase(s->lun);
296     cmdlen = fifo8_num_used(&s->cmdfifo);
297     if (!cmdlen || !s->current_dev) {
298         return;
299     }
300     esp_fifo_pop_buf(&s->cmdfifo, buf, cmdlen);
301 
302     current_lun = scsi_device_find(&s->bus, 0, s->current_dev->id, s->lun);
303     if (!current_lun) {
304         /* No such drive */
305         s->rregs[ESP_RSTAT] = 0;
306         s->rregs[ESP_RINTR] = INTR_DC;
307         s->rregs[ESP_RSEQ] = SEQ_0;
308         esp_raise_irq(s);
309         return;
310     }
311 
312     s->current_req = scsi_req_new(current_lun, 0, s->lun, buf, cmdlen, s);
313     datalen = scsi_req_enqueue(s->current_req);
314     s->ti_size = datalen;
315     fifo8_reset(&s->cmdfifo);
316     if (datalen != 0) {
317         s->rregs[ESP_RSTAT] = STAT_TC;
318         s->rregs[ESP_RSEQ] = SEQ_CD;
319         s->ti_cmd = 0;
320         esp_set_tc(s, 0);
321         if (datalen > 0) {
322             /*
323              * Switch to DATA IN phase but wait until initial data xfer is
324              * complete before raising the command completion interrupt
325              */
326             s->data_in_ready = false;
327             s->rregs[ESP_RSTAT] |= STAT_DI;
328         } else {
329             s->rregs[ESP_RSTAT] |= STAT_DO;
330             s->rregs[ESP_RINTR] |= INTR_BS | INTR_FC;
331             esp_raise_irq(s);
332             esp_lower_drq(s);
333         }
334         scsi_req_continue(s->current_req);
335         return;
336     }
337 }
338 
339 static void do_message_phase(ESPState *s)
340 {
341     if (s->cmdfifo_cdb_offset) {
342         uint8_t message = esp_fifo_pop(&s->cmdfifo);
343 
344         trace_esp_do_identify(message);
345         s->lun = message & 7;
346         s->cmdfifo_cdb_offset--;
347     }
348 
349     /* Ignore extended messages for now */
350     if (s->cmdfifo_cdb_offset) {
351         int len = MIN(s->cmdfifo_cdb_offset, fifo8_num_used(&s->cmdfifo));
352         esp_fifo_pop_buf(&s->cmdfifo, NULL, len);
353         s->cmdfifo_cdb_offset = 0;
354     }
355 }
356 
357 static void do_cmd(ESPState *s)
358 {
359     do_message_phase(s);
360     assert(s->cmdfifo_cdb_offset == 0);
361     do_command_phase(s);
362 }
363 
364 static void satn_pdma_cb(ESPState *s)
365 {
366     if (!esp_get_tc(s) && !fifo8_is_empty(&s->cmdfifo)) {
367         s->cmdfifo_cdb_offset = 1;
368         s->do_cmd = 0;
369         do_cmd(s);
370     }
371 }
372 
373 static void handle_satn(ESPState *s)
374 {
375     int32_t cmdlen;
376 
377     if (s->dma && !s->dma_enabled) {
378         s->dma_cb = handle_satn;
379         return;
380     }
381     esp_set_pdma_cb(s, SATN_PDMA_CB);
382     if (esp_select(s) < 0) {
383         return;
384     }
385     cmdlen = get_cmd(s, ESP_CMDFIFO_SZ);
386     if (cmdlen > 0) {
387         s->cmdfifo_cdb_offset = 1;
388         s->do_cmd = 0;
389         do_cmd(s);
390     } else if (cmdlen == 0) {
391         if (s->dma) {
392             esp_raise_drq(s);
393         }
394         s->do_cmd = 1;
395         /* Target present, but no cmd yet - switch to command phase */
396         s->rregs[ESP_RSEQ] = SEQ_CD;
397         s->rregs[ESP_RSTAT] = STAT_CD;
398     }
399 }
400 
401 static void s_without_satn_pdma_cb(ESPState *s)
402 {
403     if (!esp_get_tc(s) && !fifo8_is_empty(&s->cmdfifo)) {
404         s->cmdfifo_cdb_offset = 0;
405         s->do_cmd = 0;
406         do_cmd(s);
407     }
408 }
409 
410 static void handle_s_without_atn(ESPState *s)
411 {
412     int32_t cmdlen;
413 
414     if (s->dma && !s->dma_enabled) {
415         s->dma_cb = handle_s_without_atn;
416         return;
417     }
418     esp_set_pdma_cb(s, S_WITHOUT_SATN_PDMA_CB);
419     if (esp_select(s) < 0) {
420         return;
421     }
422     cmdlen = get_cmd(s, ESP_CMDFIFO_SZ);
423     if (cmdlen > 0) {
424         s->cmdfifo_cdb_offset = 0;
425         s->do_cmd = 0;
426         do_cmd(s);
427     } else if (cmdlen == 0) {
428         if (s->dma) {
429             esp_raise_drq(s);
430         }
431         s->do_cmd = 1;
432         /* Target present, but no cmd yet - switch to command phase */
433         s->rregs[ESP_RSEQ] = SEQ_CD;
434         s->rregs[ESP_RSTAT] = STAT_CD;
435     }
436 }
437 
438 static void satn_stop_pdma_cb(ESPState *s)
439 {
440     if (!esp_get_tc(s) && !fifo8_is_empty(&s->cmdfifo)) {
441         trace_esp_handle_satn_stop(fifo8_num_used(&s->cmdfifo));
442         s->do_cmd = 1;
443         s->cmdfifo_cdb_offset = 1;
444         s->rregs[ESP_RSTAT] = STAT_TC | STAT_CD;
445         s->rregs[ESP_RINTR] |= INTR_BS | INTR_FC;
446         s->rregs[ESP_RSEQ] = SEQ_CD;
447         esp_raise_irq(s);
448     }
449 }
450 
451 static void handle_satn_stop(ESPState *s)
452 {
453     int32_t cmdlen;
454 
455     if (s->dma && !s->dma_enabled) {
456         s->dma_cb = handle_satn_stop;
457         return;
458     }
459     esp_set_pdma_cb(s, SATN_STOP_PDMA_CB);
460     if (esp_select(s) < 0) {
461         return;
462     }
463     cmdlen = get_cmd(s, 1);
464     if (cmdlen > 0) {
465         trace_esp_handle_satn_stop(fifo8_num_used(&s->cmdfifo));
466         s->do_cmd = 1;
467         s->cmdfifo_cdb_offset = 1;
468         s->rregs[ESP_RSTAT] = STAT_MO;
469         s->rregs[ESP_RINTR] |= INTR_BS | INTR_FC;
470         s->rregs[ESP_RSEQ] = SEQ_MO;
471         esp_raise_irq(s);
472     } else if (cmdlen == 0) {
473         if (s->dma) {
474             esp_raise_drq(s);
475         }
476         s->do_cmd = 1;
477         /* Target present, switch to message out phase */
478         s->rregs[ESP_RSEQ] = SEQ_MO;
479         s->rregs[ESP_RSTAT] = STAT_MO;
480     }
481 }
482 
483 static void write_response_pdma_cb(ESPState *s)
484 {
485     s->rregs[ESP_RSTAT] = STAT_TC | STAT_ST;
486     s->rregs[ESP_RINTR] |= INTR_BS | INTR_FC;
487     s->rregs[ESP_RSEQ] = SEQ_CD;
488     esp_raise_irq(s);
489 }
490 
491 static void write_response(ESPState *s)
492 {
493     uint8_t buf[2];
494 
495     trace_esp_write_response(s->status);
496 
497     buf[0] = s->status;
498     buf[1] = 0;
499 
500     if (s->dma) {
501         if (s->dma_memory_write) {
502             s->dma_memory_write(s->dma_opaque, buf, 2);
503             s->rregs[ESP_RSTAT] = STAT_TC | STAT_ST;
504             s->rregs[ESP_RINTR] |= INTR_BS | INTR_FC;
505             s->rregs[ESP_RSEQ] = SEQ_CD;
506         } else {
507             esp_set_pdma_cb(s, WRITE_RESPONSE_PDMA_CB);
508             esp_raise_drq(s);
509             return;
510         }
511     } else {
512         fifo8_reset(&s->fifo);
513         fifo8_push_all(&s->fifo, buf, 2);
514         s->rregs[ESP_RFLAGS] = 2;
515     }
516     esp_raise_irq(s);
517 }
518 
519 static void esp_dma_done(ESPState *s)
520 {
521     s->rregs[ESP_RSTAT] |= STAT_TC;
522     s->rregs[ESP_RINTR] |= INTR_BS;
523     s->rregs[ESP_RFLAGS] = 0;
524     esp_set_tc(s, 0);
525     esp_raise_irq(s);
526 }
527 
528 static void do_dma_pdma_cb(ESPState *s)
529 {
530     int to_device = ((s->rregs[ESP_RSTAT] & 7) == STAT_DO);
531     int len;
532     uint32_t n;
533 
534     if (s->do_cmd) {
535         /* Ensure we have received complete command after SATN and stop */
536         if (esp_get_tc(s) || fifo8_is_empty(&s->cmdfifo)) {
537             return;
538         }
539 
540         s->ti_size = 0;
541         if ((s->rregs[ESP_RSTAT] & 7) == STAT_CD) {
542             /* No command received */
543             if (s->cmdfifo_cdb_offset == fifo8_num_used(&s->cmdfifo)) {
544                 return;
545             }
546 
547             /* Command has been received */
548             s->do_cmd = 0;
549             do_cmd(s);
550         } else {
551             /*
552              * Extra message out bytes received: update cmdfifo_cdb_offset
553              * and then switch to command phase
554              */
555             s->cmdfifo_cdb_offset = fifo8_num_used(&s->cmdfifo);
556             s->rregs[ESP_RSTAT] = STAT_TC | STAT_CD;
557             s->rregs[ESP_RSEQ] = SEQ_CD;
558             s->rregs[ESP_RINTR] |= INTR_BS;
559             esp_raise_irq(s);
560         }
561         return;
562     }
563 
564     if (!s->current_req) {
565         return;
566     }
567 
568     if (to_device) {
569         /* Copy FIFO data to device */
570         len = MIN(s->async_len, ESP_FIFO_SZ);
571         len = MIN(len, fifo8_num_used(&s->fifo));
572         n = esp_fifo_pop_buf(&s->fifo, s->async_buf, len);
573         s->async_buf += n;
574         s->async_len -= n;
575         s->ti_size += n;
576 
577         if (n < len) {
578             /* Unaligned accesses can cause FIFO wraparound */
579             len = len - n;
580             n = esp_fifo_pop_buf(&s->fifo, s->async_buf, len);
581             s->async_buf += n;
582             s->async_len -= n;
583             s->ti_size += n;
584         }
585 
586         if (s->async_len == 0) {
587             scsi_req_continue(s->current_req);
588             return;
589         }
590 
591         if (esp_get_tc(s) == 0) {
592             esp_lower_drq(s);
593             esp_dma_done(s);
594         }
595 
596         return;
597     } else {
598         if (s->async_len == 0) {
599             /* Defer until the scsi layer has completed */
600             scsi_req_continue(s->current_req);
601             s->data_in_ready = false;
602             return;
603         }
604 
605         if (esp_get_tc(s) != 0) {
606             /* Copy device data to FIFO */
607             len = MIN(s->async_len, esp_get_tc(s));
608             len = MIN(len, fifo8_num_free(&s->fifo));
609             fifo8_push_all(&s->fifo, s->async_buf, len);
610             s->async_buf += len;
611             s->async_len -= len;
612             s->ti_size -= len;
613             esp_set_tc(s, esp_get_tc(s) - len);
614 
615             if (esp_get_tc(s) == 0) {
616                 /* Indicate transfer to FIFO is complete */
617                  s->rregs[ESP_RSTAT] |= STAT_TC;
618             }
619             return;
620         }
621 
622         /* Partially filled a scsi buffer. Complete immediately.  */
623         esp_lower_drq(s);
624         esp_dma_done(s);
625     }
626 }
627 
628 static void esp_do_dma(ESPState *s)
629 {
630     uint32_t len, cmdlen;
631     int to_device = ((s->rregs[ESP_RSTAT] & 7) == STAT_DO);
632     uint8_t buf[ESP_CMDFIFO_SZ];
633 
634     len = esp_get_tc(s);
635     if (s->do_cmd) {
636         /*
637          * handle_ti_cmd() case: esp_do_dma() is called only from
638          * handle_ti_cmd() with do_cmd != NULL (see the assert())
639          */
640         cmdlen = fifo8_num_used(&s->cmdfifo);
641         trace_esp_do_dma(cmdlen, len);
642         if (s->dma_memory_read) {
643             len = MIN(len, fifo8_num_free(&s->cmdfifo));
644             s->dma_memory_read(s->dma_opaque, buf, len);
645             fifo8_push_all(&s->cmdfifo, buf, len);
646         } else {
647             esp_set_pdma_cb(s, DO_DMA_PDMA_CB);
648             esp_raise_drq(s);
649             return;
650         }
651         trace_esp_handle_ti_cmd(cmdlen);
652         s->ti_size = 0;
653         if ((s->rregs[ESP_RSTAT] & 7) == STAT_CD) {
654             /* No command received */
655             if (s->cmdfifo_cdb_offset == fifo8_num_used(&s->cmdfifo)) {
656                 return;
657             }
658 
659             /* Command has been received */
660             s->do_cmd = 0;
661             do_cmd(s);
662         } else {
663             /*
664              * Extra message out bytes received: update cmdfifo_cdb_offset
665              * and then switch to command phase
666              */
667             s->cmdfifo_cdb_offset = fifo8_num_used(&s->cmdfifo);
668             s->rregs[ESP_RSTAT] = STAT_TC | STAT_CD;
669             s->rregs[ESP_RSEQ] = SEQ_CD;
670             s->rregs[ESP_RINTR] |= INTR_BS;
671             esp_raise_irq(s);
672         }
673         return;
674     }
675     if (!s->current_req) {
676         return;
677     }
678     if (s->async_len == 0) {
679         /* Defer until data is available.  */
680         return;
681     }
682     if (len > s->async_len) {
683         len = s->async_len;
684     }
685     if (to_device) {
686         if (s->dma_memory_read) {
687             s->dma_memory_read(s->dma_opaque, s->async_buf, len);
688         } else {
689             esp_set_pdma_cb(s, DO_DMA_PDMA_CB);
690             esp_raise_drq(s);
691             return;
692         }
693     } else {
694         if (s->dma_memory_write) {
695             s->dma_memory_write(s->dma_opaque, s->async_buf, len);
696         } else {
697             /* Adjust TC for any leftover data in the FIFO */
698             if (!fifo8_is_empty(&s->fifo)) {
699                 esp_set_tc(s, esp_get_tc(s) - fifo8_num_used(&s->fifo));
700             }
701 
702             /* Copy device data to FIFO */
703             len = MIN(len, fifo8_num_free(&s->fifo));
704             fifo8_push_all(&s->fifo, s->async_buf, len);
705             s->async_buf += len;
706             s->async_len -= len;
707             s->ti_size -= len;
708 
709             /*
710              * MacOS toolbox uses a TI length of 16 bytes for all commands, so
711              * commands shorter than this must be padded accordingly
712              */
713             if (len < esp_get_tc(s) && esp_get_tc(s) <= ESP_FIFO_SZ) {
714                 while (fifo8_num_used(&s->fifo) < ESP_FIFO_SZ) {
715                     esp_fifo_push(&s->fifo, 0);
716                     len++;
717                 }
718             }
719 
720             esp_set_tc(s, esp_get_tc(s) - len);
721             esp_set_pdma_cb(s, DO_DMA_PDMA_CB);
722             esp_raise_drq(s);
723 
724             /* Indicate transfer to FIFO is complete */
725             s->rregs[ESP_RSTAT] |= STAT_TC;
726             return;
727         }
728     }
729     esp_set_tc(s, esp_get_tc(s) - len);
730     s->async_buf += len;
731     s->async_len -= len;
732     if (to_device) {
733         s->ti_size += len;
734     } else {
735         s->ti_size -= len;
736     }
737     if (s->async_len == 0) {
738         scsi_req_continue(s->current_req);
739         /*
740          * If there is still data to be read from the device then
741          * complete the DMA operation immediately.  Otherwise defer
742          * until the scsi layer has completed.
743          */
744         if (to_device || esp_get_tc(s) != 0 || s->ti_size == 0) {
745             return;
746         }
747     }
748 
749     /* Partially filled a scsi buffer. Complete immediately.  */
750     esp_dma_done(s);
751     esp_lower_drq(s);
752 }
753 
754 static void esp_do_nodma(ESPState *s)
755 {
756     int to_device = ((s->rregs[ESP_RSTAT] & 7) == STAT_DO);
757     uint32_t cmdlen;
758     int len;
759 
760     if (s->do_cmd) {
761         cmdlen = fifo8_num_used(&s->cmdfifo);
762         trace_esp_handle_ti_cmd(cmdlen);
763         s->ti_size = 0;
764         if ((s->rregs[ESP_RSTAT] & 7) == STAT_CD) {
765             /* No command received */
766             if (s->cmdfifo_cdb_offset == fifo8_num_used(&s->cmdfifo)) {
767                 return;
768             }
769 
770             /* Command has been received */
771             s->do_cmd = 0;
772             do_cmd(s);
773         } else {
774             /*
775              * Extra message out bytes received: update cmdfifo_cdb_offset
776              * and then switch to command phase
777              */
778             s->cmdfifo_cdb_offset = fifo8_num_used(&s->cmdfifo);
779             s->rregs[ESP_RSTAT] = STAT_TC | STAT_CD;
780             s->rregs[ESP_RSEQ] = SEQ_CD;
781             s->rregs[ESP_RINTR] |= INTR_BS;
782             esp_raise_irq(s);
783         }
784         return;
785     }
786 
787     if (!s->current_req) {
788         return;
789     }
790 
791     if (s->async_len == 0) {
792         /* Defer until data is available.  */
793         return;
794     }
795 
796     if (to_device) {
797         len = MIN(s->async_len, ESP_FIFO_SZ);
798         len = MIN(len, fifo8_num_used(&s->fifo));
799         esp_fifo_pop_buf(&s->fifo, s->async_buf, len);
800         s->async_buf += len;
801         s->async_len -= len;
802         s->ti_size += len;
803     } else {
804         if (fifo8_is_empty(&s->fifo)) {
805             fifo8_push(&s->fifo, s->async_buf[0]);
806             s->async_buf++;
807             s->async_len--;
808             s->ti_size--;
809         }
810     }
811 
812     if (s->async_len == 0) {
813         scsi_req_continue(s->current_req);
814         return;
815     }
816 
817     s->rregs[ESP_RINTR] |= INTR_BS;
818     esp_raise_irq(s);
819 }
820 
821 static void esp_pdma_cb(ESPState *s)
822 {
823     switch (s->pdma_cb) {
824     case SATN_PDMA_CB:
825         satn_pdma_cb(s);
826         break;
827     case S_WITHOUT_SATN_PDMA_CB:
828         s_without_satn_pdma_cb(s);
829         break;
830     case SATN_STOP_PDMA_CB:
831         satn_stop_pdma_cb(s);
832         break;
833     case WRITE_RESPONSE_PDMA_CB:
834         write_response_pdma_cb(s);
835         break;
836     case DO_DMA_PDMA_CB:
837         do_dma_pdma_cb(s);
838         break;
839     default:
840         g_assert_not_reached();
841     }
842 }
843 
844 void esp_command_complete(SCSIRequest *req, size_t resid)
845 {
846     ESPState *s = req->hba_private;
847     int to_device = ((s->rregs[ESP_RSTAT] & 7) == STAT_DO);
848 
849     trace_esp_command_complete();
850 
851     /*
852      * Non-DMA transfers from the target will leave the last byte in
853      * the FIFO so don't reset ti_size in this case
854      */
855     if (s->dma || to_device) {
856         if (s->ti_size != 0) {
857             trace_esp_command_complete_unexpected();
858         }
859         s->ti_size = 0;
860     }
861 
862     s->async_len = 0;
863     if (req->status) {
864         trace_esp_command_complete_fail();
865     }
866     s->status = req->status;
867 
868     /*
869      * If the transfer is finished, switch to status phase. For non-DMA
870      * transfers from the target the last byte is still in the FIFO
871      */
872     if (s->ti_size == 0) {
873         s->rregs[ESP_RSTAT] = STAT_TC | STAT_ST;
874         esp_dma_done(s);
875         esp_lower_drq(s);
876     }
877 
878     if (s->current_req) {
879         scsi_req_unref(s->current_req);
880         s->current_req = NULL;
881         s->current_dev = NULL;
882     }
883 }
884 
885 void esp_transfer_data(SCSIRequest *req, uint32_t len)
886 {
887     ESPState *s = req->hba_private;
888     int to_device = ((s->rregs[ESP_RSTAT] & 7) == STAT_DO);
889     uint32_t dmalen = esp_get_tc(s);
890 
891     assert(!s->do_cmd);
892     trace_esp_transfer_data(dmalen, s->ti_size);
893     s->async_len = len;
894     s->async_buf = scsi_req_get_buf(req);
895 
896     if (!to_device && !s->data_in_ready) {
897         /*
898          * Initial incoming data xfer is complete so raise command
899          * completion interrupt
900          */
901         s->data_in_ready = true;
902         s->rregs[ESP_RSTAT] |= STAT_TC;
903         s->rregs[ESP_RINTR] |= INTR_BS;
904         esp_raise_irq(s);
905     }
906 
907     if (s->ti_cmd == 0) {
908         /*
909          * Always perform the initial transfer upon reception of the next TI
910          * command to ensure the DMA/non-DMA status of the command is correct.
911          * It is not possible to use s->dma directly in the section below as
912          * some OSs send non-DMA NOP commands after a DMA transfer. Hence if the
913          * async data transfer is delayed then s->dma is set incorrectly.
914          */
915         return;
916     }
917 
918     if (s->ti_cmd == (CMD_TI | CMD_DMA)) {
919         if (dmalen) {
920             esp_do_dma(s);
921         } else if (s->ti_size <= 0) {
922             /*
923              * If this was the last part of a DMA transfer then the
924              * completion interrupt is deferred to here.
925              */
926             esp_dma_done(s);
927             esp_lower_drq(s);
928         }
929     } else if (s->ti_cmd == CMD_TI) {
930         esp_do_nodma(s);
931     }
932 }
933 
934 static void handle_ti(ESPState *s)
935 {
936     uint32_t dmalen;
937 
938     if (s->dma && !s->dma_enabled) {
939         s->dma_cb = handle_ti;
940         return;
941     }
942 
943     s->ti_cmd = s->rregs[ESP_CMD];
944     if (s->dma) {
945         dmalen = esp_get_tc(s);
946         trace_esp_handle_ti(dmalen);
947         s->rregs[ESP_RSTAT] &= ~STAT_TC;
948         esp_do_dma(s);
949     } else {
950         trace_esp_handle_ti(s->ti_size);
951         esp_do_nodma(s);
952     }
953 }
954 
955 void esp_hard_reset(ESPState *s)
956 {
957     memset(s->rregs, 0, ESP_REGS);
958     memset(s->wregs, 0, ESP_REGS);
959     s->tchi_written = 0;
960     s->ti_size = 0;
961     s->async_len = 0;
962     fifo8_reset(&s->fifo);
963     fifo8_reset(&s->cmdfifo);
964     s->dma = 0;
965     s->do_cmd = 0;
966     s->dma_cb = NULL;
967 
968     s->rregs[ESP_CFG1] = 7;
969 }
970 
971 static void esp_soft_reset(ESPState *s)
972 {
973     qemu_irq_lower(s->irq);
974     qemu_irq_lower(s->irq_data);
975     esp_hard_reset(s);
976 }
977 
978 static void esp_bus_reset(ESPState *s)
979 {
980     bus_cold_reset(BUS(&s->bus));
981 }
982 
983 static void parent_esp_reset(ESPState *s, int irq, int level)
984 {
985     if (level) {
986         esp_soft_reset(s);
987     }
988 }
989 
990 uint64_t esp_reg_read(ESPState *s, uint32_t saddr)
991 {
992     uint32_t val;
993 
994     switch (saddr) {
995     case ESP_FIFO:
996         if (s->dma_memory_read && s->dma_memory_write &&
997                 (s->rregs[ESP_RSTAT] & STAT_PIO_MASK) == 0) {
998             /* Data out.  */
999             qemu_log_mask(LOG_UNIMP, "esp: PIO data read not implemented\n");
1000             s->rregs[ESP_FIFO] = 0;
1001         } else {
1002             if ((s->rregs[ESP_RSTAT] & 0x7) == STAT_DI) {
1003                 if (s->ti_size) {
1004                     esp_do_nodma(s);
1005                 } else {
1006                     /*
1007                      * The last byte of a non-DMA transfer has been read out
1008                      * of the FIFO so switch to status phase
1009                      */
1010                     s->rregs[ESP_RSTAT] = STAT_TC | STAT_ST;
1011                 }
1012             }
1013             s->rregs[ESP_FIFO] = esp_fifo_pop(&s->fifo);
1014         }
1015         val = s->rregs[ESP_FIFO];
1016         break;
1017     case ESP_RINTR:
1018         /*
1019          * Clear sequence step, interrupt register and all status bits
1020          * except TC
1021          */
1022         val = s->rregs[ESP_RINTR];
1023         s->rregs[ESP_RINTR] = 0;
1024         s->rregs[ESP_RSTAT] &= ~STAT_TC;
1025         /*
1026          * According to the datasheet ESP_RSEQ should be cleared, but as the
1027          * emulation currently defers information transfers to the next TI
1028          * command leave it for now so that pedantic guests such as the old
1029          * Linux 2.6 driver see the correct flags before the next SCSI phase
1030          * transition.
1031          *
1032          * s->rregs[ESP_RSEQ] = SEQ_0;
1033          */
1034         esp_lower_irq(s);
1035         break;
1036     case ESP_TCHI:
1037         /* Return the unique id if the value has never been written */
1038         if (!s->tchi_written) {
1039             val = s->chip_id;
1040         } else {
1041             val = s->rregs[saddr];
1042         }
1043         break;
1044      case ESP_RFLAGS:
1045         /* Bottom 5 bits indicate number of bytes in FIFO */
1046         val = fifo8_num_used(&s->fifo);
1047         break;
1048     default:
1049         val = s->rregs[saddr];
1050         break;
1051     }
1052 
1053     trace_esp_mem_readb(saddr, val);
1054     return val;
1055 }
1056 
1057 void esp_reg_write(ESPState *s, uint32_t saddr, uint64_t val)
1058 {
1059     trace_esp_mem_writeb(saddr, s->wregs[saddr], val);
1060     switch (saddr) {
1061     case ESP_TCHI:
1062         s->tchi_written = true;
1063         /* fall through */
1064     case ESP_TCLO:
1065     case ESP_TCMID:
1066         s->rregs[ESP_RSTAT] &= ~STAT_TC;
1067         break;
1068     case ESP_FIFO:
1069         if (s->do_cmd) {
1070             esp_fifo_push(&s->cmdfifo, val);
1071 
1072             /*
1073              * If any unexpected message out/command phase data is
1074              * transferred using non-DMA, raise the interrupt
1075              */
1076             if (s->rregs[ESP_CMD] == CMD_TI) {
1077                 s->rregs[ESP_RINTR] |= INTR_BS;
1078                 esp_raise_irq(s);
1079             }
1080         } else {
1081             esp_fifo_push(&s->fifo, val);
1082         }
1083         break;
1084     case ESP_CMD:
1085         s->rregs[saddr] = val;
1086         if (val & CMD_DMA) {
1087             s->dma = 1;
1088             /* Reload DMA counter.  */
1089             if (esp_get_stc(s) == 0) {
1090                 esp_set_tc(s, 0x10000);
1091             } else {
1092                 esp_set_tc(s, esp_get_stc(s));
1093             }
1094         } else {
1095             s->dma = 0;
1096         }
1097         switch (val & CMD_CMD) {
1098         case CMD_NOP:
1099             trace_esp_mem_writeb_cmd_nop(val);
1100             break;
1101         case CMD_FLUSH:
1102             trace_esp_mem_writeb_cmd_flush(val);
1103             fifo8_reset(&s->fifo);
1104             break;
1105         case CMD_RESET:
1106             trace_esp_mem_writeb_cmd_reset(val);
1107             esp_soft_reset(s);
1108             break;
1109         case CMD_BUSRESET:
1110             trace_esp_mem_writeb_cmd_bus_reset(val);
1111             esp_bus_reset(s);
1112             if (!(s->wregs[ESP_CFG1] & CFG1_RESREPT)) {
1113                 s->rregs[ESP_RINTR] |= INTR_RST;
1114                 esp_raise_irq(s);
1115             }
1116             break;
1117         case CMD_TI:
1118             trace_esp_mem_writeb_cmd_ti(val);
1119             handle_ti(s);
1120             break;
1121         case CMD_ICCS:
1122             trace_esp_mem_writeb_cmd_iccs(val);
1123             write_response(s);
1124             s->rregs[ESP_RINTR] |= INTR_FC;
1125             s->rregs[ESP_RSTAT] |= STAT_MI;
1126             break;
1127         case CMD_MSGACC:
1128             trace_esp_mem_writeb_cmd_msgacc(val);
1129             s->rregs[ESP_RINTR] |= INTR_DC;
1130             s->rregs[ESP_RSEQ] = 0;
1131             s->rregs[ESP_RFLAGS] = 0;
1132             esp_raise_irq(s);
1133             break;
1134         case CMD_PAD:
1135             trace_esp_mem_writeb_cmd_pad(val);
1136             s->rregs[ESP_RSTAT] = STAT_TC;
1137             s->rregs[ESP_RINTR] |= INTR_FC;
1138             s->rregs[ESP_RSEQ] = 0;
1139             break;
1140         case CMD_SATN:
1141             trace_esp_mem_writeb_cmd_satn(val);
1142             break;
1143         case CMD_RSTATN:
1144             trace_esp_mem_writeb_cmd_rstatn(val);
1145             break;
1146         case CMD_SEL:
1147             trace_esp_mem_writeb_cmd_sel(val);
1148             handle_s_without_atn(s);
1149             break;
1150         case CMD_SELATN:
1151             trace_esp_mem_writeb_cmd_selatn(val);
1152             handle_satn(s);
1153             break;
1154         case CMD_SELATNS:
1155             trace_esp_mem_writeb_cmd_selatns(val);
1156             handle_satn_stop(s);
1157             break;
1158         case CMD_ENSEL:
1159             trace_esp_mem_writeb_cmd_ensel(val);
1160             s->rregs[ESP_RINTR] = 0;
1161             break;
1162         case CMD_DISSEL:
1163             trace_esp_mem_writeb_cmd_dissel(val);
1164             s->rregs[ESP_RINTR] = 0;
1165             esp_raise_irq(s);
1166             break;
1167         default:
1168             trace_esp_error_unhandled_command(val);
1169             break;
1170         }
1171         break;
1172     case ESP_WBUSID ... ESP_WSYNO:
1173         break;
1174     case ESP_CFG1:
1175     case ESP_CFG2: case ESP_CFG3:
1176     case ESP_RES3: case ESP_RES4:
1177         s->rregs[saddr] = val;
1178         break;
1179     case ESP_WCCF ... ESP_WTEST:
1180         break;
1181     default:
1182         trace_esp_error_invalid_write(val, saddr);
1183         return;
1184     }
1185     s->wregs[saddr] = val;
1186 }
1187 
1188 static bool esp_mem_accepts(void *opaque, hwaddr addr,
1189                             unsigned size, bool is_write,
1190                             MemTxAttrs attrs)
1191 {
1192     return (size == 1) || (is_write && size == 4);
1193 }
1194 
1195 static bool esp_is_before_version_5(void *opaque, int version_id)
1196 {
1197     ESPState *s = ESP(opaque);
1198 
1199     version_id = MIN(version_id, s->mig_version_id);
1200     return version_id < 5;
1201 }
1202 
1203 static bool esp_is_version_5(void *opaque, int version_id)
1204 {
1205     ESPState *s = ESP(opaque);
1206 
1207     version_id = MIN(version_id, s->mig_version_id);
1208     return version_id >= 5;
1209 }
1210 
1211 static bool esp_is_version_6(void *opaque, int version_id)
1212 {
1213     ESPState *s = ESP(opaque);
1214 
1215     version_id = MIN(version_id, s->mig_version_id);
1216     return version_id >= 6;
1217 }
1218 
1219 int esp_pre_save(void *opaque)
1220 {
1221     ESPState *s = ESP(object_resolve_path_component(
1222                       OBJECT(opaque), "esp"));
1223 
1224     s->mig_version_id = vmstate_esp.version_id;
1225     return 0;
1226 }
1227 
1228 static int esp_post_load(void *opaque, int version_id)
1229 {
1230     ESPState *s = ESP(opaque);
1231     int len, i;
1232 
1233     version_id = MIN(version_id, s->mig_version_id);
1234 
1235     if (version_id < 5) {
1236         esp_set_tc(s, s->mig_dma_left);
1237 
1238         /* Migrate ti_buf to fifo */
1239         len = s->mig_ti_wptr - s->mig_ti_rptr;
1240         for (i = 0; i < len; i++) {
1241             fifo8_push(&s->fifo, s->mig_ti_buf[i]);
1242         }
1243 
1244         /* Migrate cmdbuf to cmdfifo */
1245         for (i = 0; i < s->mig_cmdlen; i++) {
1246             fifo8_push(&s->cmdfifo, s->mig_cmdbuf[i]);
1247         }
1248     }
1249 
1250     s->mig_version_id = vmstate_esp.version_id;
1251     return 0;
1252 }
1253 
1254 /*
1255  * PDMA (or pseudo-DMA) is only used on the Macintosh and requires the
1256  * guest CPU to perform the transfers between the SCSI bus and memory
1257  * itself. This is indicated by the dma_memory_read and dma_memory_write
1258  * functions being NULL (in contrast to the ESP PCI device) whilst
1259  * dma_enabled is still set.
1260  */
1261 
1262 static bool esp_pdma_needed(void *opaque)
1263 {
1264     ESPState *s = ESP(opaque);
1265 
1266     return s->dma_memory_read == NULL && s->dma_memory_write == NULL &&
1267            s->dma_enabled;
1268 }
1269 
1270 static const VMStateDescription vmstate_esp_pdma = {
1271     .name = "esp/pdma",
1272     .version_id = 0,
1273     .minimum_version_id = 0,
1274     .needed = esp_pdma_needed,
1275     .fields = (const VMStateField[]) {
1276         VMSTATE_UINT8(pdma_cb, ESPState),
1277         VMSTATE_END_OF_LIST()
1278     }
1279 };
1280 
1281 const VMStateDescription vmstate_esp = {
1282     .name = "esp",
1283     .version_id = 6,
1284     .minimum_version_id = 3,
1285     .post_load = esp_post_load,
1286     .fields = (const VMStateField[]) {
1287         VMSTATE_BUFFER(rregs, ESPState),
1288         VMSTATE_BUFFER(wregs, ESPState),
1289         VMSTATE_INT32(ti_size, ESPState),
1290         VMSTATE_UINT32_TEST(mig_ti_rptr, ESPState, esp_is_before_version_5),
1291         VMSTATE_UINT32_TEST(mig_ti_wptr, ESPState, esp_is_before_version_5),
1292         VMSTATE_BUFFER_TEST(mig_ti_buf, ESPState, esp_is_before_version_5),
1293         VMSTATE_UINT32(status, ESPState),
1294         VMSTATE_UINT32_TEST(mig_deferred_status, ESPState,
1295                             esp_is_before_version_5),
1296         VMSTATE_BOOL_TEST(mig_deferred_complete, ESPState,
1297                           esp_is_before_version_5),
1298         VMSTATE_UINT32(dma, ESPState),
1299         VMSTATE_STATIC_BUFFER(mig_cmdbuf, ESPState, 0,
1300                               esp_is_before_version_5, 0, 16),
1301         VMSTATE_STATIC_BUFFER(mig_cmdbuf, ESPState, 4,
1302                               esp_is_before_version_5, 16,
1303                               sizeof(typeof_field(ESPState, mig_cmdbuf))),
1304         VMSTATE_UINT32_TEST(mig_cmdlen, ESPState, esp_is_before_version_5),
1305         VMSTATE_UINT32(do_cmd, ESPState),
1306         VMSTATE_UINT32_TEST(mig_dma_left, ESPState, esp_is_before_version_5),
1307         VMSTATE_BOOL_TEST(data_in_ready, ESPState, esp_is_version_5),
1308         VMSTATE_UINT8_TEST(cmdfifo_cdb_offset, ESPState, esp_is_version_5),
1309         VMSTATE_FIFO8_TEST(fifo, ESPState, esp_is_version_5),
1310         VMSTATE_FIFO8_TEST(cmdfifo, ESPState, esp_is_version_5),
1311         VMSTATE_UINT8_TEST(ti_cmd, ESPState, esp_is_version_5),
1312         VMSTATE_UINT8_TEST(lun, ESPState, esp_is_version_6),
1313         VMSTATE_END_OF_LIST()
1314     },
1315     .subsections = (const VMStateDescription * const []) {
1316         &vmstate_esp_pdma,
1317         NULL
1318     }
1319 };
1320 
1321 static void sysbus_esp_mem_write(void *opaque, hwaddr addr,
1322                                  uint64_t val, unsigned int size)
1323 {
1324     SysBusESPState *sysbus = opaque;
1325     ESPState *s = ESP(&sysbus->esp);
1326     uint32_t saddr;
1327 
1328     saddr = addr >> sysbus->it_shift;
1329     esp_reg_write(s, saddr, val);
1330 }
1331 
1332 static uint64_t sysbus_esp_mem_read(void *opaque, hwaddr addr,
1333                                     unsigned int size)
1334 {
1335     SysBusESPState *sysbus = opaque;
1336     ESPState *s = ESP(&sysbus->esp);
1337     uint32_t saddr;
1338 
1339     saddr = addr >> sysbus->it_shift;
1340     return esp_reg_read(s, saddr);
1341 }
1342 
1343 static const MemoryRegionOps sysbus_esp_mem_ops = {
1344     .read = sysbus_esp_mem_read,
1345     .write = sysbus_esp_mem_write,
1346     .endianness = DEVICE_NATIVE_ENDIAN,
1347     .valid.accepts = esp_mem_accepts,
1348 };
1349 
1350 static void sysbus_esp_pdma_write(void *opaque, hwaddr addr,
1351                                   uint64_t val, unsigned int size)
1352 {
1353     SysBusESPState *sysbus = opaque;
1354     ESPState *s = ESP(&sysbus->esp);
1355 
1356     trace_esp_pdma_write(size);
1357 
1358     switch (size) {
1359     case 1:
1360         esp_pdma_write(s, val);
1361         break;
1362     case 2:
1363         esp_pdma_write(s, val >> 8);
1364         esp_pdma_write(s, val);
1365         break;
1366     }
1367     esp_pdma_cb(s);
1368 }
1369 
1370 static uint64_t sysbus_esp_pdma_read(void *opaque, hwaddr addr,
1371                                      unsigned int size)
1372 {
1373     SysBusESPState *sysbus = opaque;
1374     ESPState *s = ESP(&sysbus->esp);
1375     uint64_t val = 0;
1376 
1377     trace_esp_pdma_read(size);
1378 
1379     switch (size) {
1380     case 1:
1381         val = esp_pdma_read(s);
1382         break;
1383     case 2:
1384         val = esp_pdma_read(s);
1385         val = (val << 8) | esp_pdma_read(s);
1386         break;
1387     }
1388     if (fifo8_num_used(&s->fifo) < 2) {
1389         esp_pdma_cb(s);
1390     }
1391     return val;
1392 }
1393 
1394 static void *esp_load_request(QEMUFile *f, SCSIRequest *req)
1395 {
1396     ESPState *s = container_of(req->bus, ESPState, bus);
1397 
1398     scsi_req_ref(req);
1399     s->current_req = req;
1400     return s;
1401 }
1402 
1403 static const MemoryRegionOps sysbus_esp_pdma_ops = {
1404     .read = sysbus_esp_pdma_read,
1405     .write = sysbus_esp_pdma_write,
1406     .endianness = DEVICE_NATIVE_ENDIAN,
1407     .valid.min_access_size = 1,
1408     .valid.max_access_size = 4,
1409     .impl.min_access_size = 1,
1410     .impl.max_access_size = 2,
1411 };
1412 
1413 static const struct SCSIBusInfo esp_scsi_info = {
1414     .tcq = false,
1415     .max_target = ESP_MAX_DEVS,
1416     .max_lun = 7,
1417 
1418     .load_request = esp_load_request,
1419     .transfer_data = esp_transfer_data,
1420     .complete = esp_command_complete,
1421     .cancel = esp_request_cancelled
1422 };
1423 
1424 static void sysbus_esp_gpio_demux(void *opaque, int irq, int level)
1425 {
1426     SysBusESPState *sysbus = SYSBUS_ESP(opaque);
1427     ESPState *s = ESP(&sysbus->esp);
1428 
1429     switch (irq) {
1430     case 0:
1431         parent_esp_reset(s, irq, level);
1432         break;
1433     case 1:
1434         esp_dma_enable(s, irq, level);
1435         break;
1436     }
1437 }
1438 
1439 static void sysbus_esp_realize(DeviceState *dev, Error **errp)
1440 {
1441     SysBusDevice *sbd = SYS_BUS_DEVICE(dev);
1442     SysBusESPState *sysbus = SYSBUS_ESP(dev);
1443     ESPState *s = ESP(&sysbus->esp);
1444 
1445     if (!qdev_realize(DEVICE(s), NULL, errp)) {
1446         return;
1447     }
1448 
1449     sysbus_init_irq(sbd, &s->irq);
1450     sysbus_init_irq(sbd, &s->irq_data);
1451     assert(sysbus->it_shift != -1);
1452 
1453     s->chip_id = TCHI_FAS100A;
1454     memory_region_init_io(&sysbus->iomem, OBJECT(sysbus), &sysbus_esp_mem_ops,
1455                           sysbus, "esp-regs", ESP_REGS << sysbus->it_shift);
1456     sysbus_init_mmio(sbd, &sysbus->iomem);
1457     memory_region_init_io(&sysbus->pdma, OBJECT(sysbus), &sysbus_esp_pdma_ops,
1458                           sysbus, "esp-pdma", 4);
1459     sysbus_init_mmio(sbd, &sysbus->pdma);
1460 
1461     qdev_init_gpio_in(dev, sysbus_esp_gpio_demux, 2);
1462 
1463     scsi_bus_init(&s->bus, sizeof(s->bus), dev, &esp_scsi_info);
1464 }
1465 
1466 static void sysbus_esp_hard_reset(DeviceState *dev)
1467 {
1468     SysBusESPState *sysbus = SYSBUS_ESP(dev);
1469     ESPState *s = ESP(&sysbus->esp);
1470 
1471     esp_hard_reset(s);
1472 }
1473 
1474 static void sysbus_esp_init(Object *obj)
1475 {
1476     SysBusESPState *sysbus = SYSBUS_ESP(obj);
1477 
1478     object_initialize_child(obj, "esp", &sysbus->esp, TYPE_ESP);
1479 }
1480 
1481 static const VMStateDescription vmstate_sysbus_esp_scsi = {
1482     .name = "sysbusespscsi",
1483     .version_id = 2,
1484     .minimum_version_id = 1,
1485     .pre_save = esp_pre_save,
1486     .fields = (const VMStateField[]) {
1487         VMSTATE_UINT8_V(esp.mig_version_id, SysBusESPState, 2),
1488         VMSTATE_STRUCT(esp, SysBusESPState, 0, vmstate_esp, ESPState),
1489         VMSTATE_END_OF_LIST()
1490     }
1491 };
1492 
1493 static void sysbus_esp_class_init(ObjectClass *klass, void *data)
1494 {
1495     DeviceClass *dc = DEVICE_CLASS(klass);
1496 
1497     dc->realize = sysbus_esp_realize;
1498     dc->reset = sysbus_esp_hard_reset;
1499     dc->vmsd = &vmstate_sysbus_esp_scsi;
1500     set_bit(DEVICE_CATEGORY_STORAGE, dc->categories);
1501 }
1502 
1503 static const TypeInfo sysbus_esp_info = {
1504     .name          = TYPE_SYSBUS_ESP,
1505     .parent        = TYPE_SYS_BUS_DEVICE,
1506     .instance_init = sysbus_esp_init,
1507     .instance_size = sizeof(SysBusESPState),
1508     .class_init    = sysbus_esp_class_init,
1509 };
1510 
1511 static void esp_finalize(Object *obj)
1512 {
1513     ESPState *s = ESP(obj);
1514 
1515     fifo8_destroy(&s->fifo);
1516     fifo8_destroy(&s->cmdfifo);
1517 }
1518 
1519 static void esp_init(Object *obj)
1520 {
1521     ESPState *s = ESP(obj);
1522 
1523     fifo8_create(&s->fifo, ESP_FIFO_SZ);
1524     fifo8_create(&s->cmdfifo, ESP_CMDFIFO_SZ);
1525 }
1526 
1527 static void esp_class_init(ObjectClass *klass, void *data)
1528 {
1529     DeviceClass *dc = DEVICE_CLASS(klass);
1530 
1531     /* internal device for sysbusesp/pciespscsi, not user-creatable */
1532     dc->user_creatable = false;
1533     set_bit(DEVICE_CATEGORY_STORAGE, dc->categories);
1534 }
1535 
1536 static const TypeInfo esp_info = {
1537     .name = TYPE_ESP,
1538     .parent = TYPE_DEVICE,
1539     .instance_init = esp_init,
1540     .instance_finalize = esp_finalize,
1541     .instance_size = sizeof(ESPState),
1542     .class_init = esp_class_init,
1543 };
1544 
1545 static void esp_register_types(void)
1546 {
1547     type_register_static(&sysbus_esp_info);
1548     type_register_static(&esp_info);
1549 }
1550 
1551 type_init(esp_register_types)
1552