xref: /openbmc/qemu/hw/misc/macio/mac_dbdma.c (revision 9121d02c)
1 /*
2  * PowerMac descriptor-based DMA emulation
3  *
4  * Copyright (c) 2005-2007 Fabrice Bellard
5  * Copyright (c) 2007 Jocelyn Mayer
6  * Copyright (c) 2009 Laurent Vivier
7  *
8  * some parts from linux-2.6.28, arch/powerpc/include/asm/dbdma.h
9  *
10  *   Definitions for using the Apple Descriptor-Based DMA controller
11  *   in Power Macintosh computers.
12  *
13  *   Copyright (C) 1996 Paul Mackerras.
14  *
15  * some parts from mol 0.9.71
16  *
17  *   Descriptor based DMA emulation
18  *
19  *   Copyright (C) 1998-2004 Samuel Rydh (samuel@ibrium.se)
20  *
21  * Permission is hereby granted, free of charge, to any person obtaining a copy
22  * of this software and associated documentation files (the "Software"), to deal
23  * in the Software without restriction, including without limitation the rights
24  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
25  * copies of the Software, and to permit persons to whom the Software is
26  * furnished to do so, subject to the following conditions:
27  *
28  * The above copyright notice and this permission notice shall be included in
29  * all copies or substantial portions of the Software.
30  *
31  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
32  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
33  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
34  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
35  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
36  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
37  * THE SOFTWARE.
38  */
39 #include "hw/hw.h"
40 #include "hw/isa/isa.h"
41 #include "hw/ppc/mac_dbdma.h"
42 #include "qemu/main-loop.h"
43 
44 /* debug DBDMA */
45 //#define DEBUG_DBDMA
46 
47 #ifdef DEBUG_DBDMA
48 #define DBDMA_DPRINTF(fmt, ...)                                 \
49     do { printf("DBDMA: " fmt , ## __VA_ARGS__); } while (0)
50 #else
51 #define DBDMA_DPRINTF(fmt, ...)
52 #endif
53 
54 /*
55  */
56 
57 static DBDMAState *dbdma_from_ch(DBDMA_channel *ch)
58 {
59     return container_of(ch, DBDMAState, channels[ch->channel]);
60 }
61 
62 #ifdef DEBUG_DBDMA
63 static void dump_dbdma_cmd(dbdma_cmd *cmd)
64 {
65     printf("dbdma_cmd %p\n", cmd);
66     printf("    req_count 0x%04x\n", le16_to_cpu(cmd->req_count));
67     printf("    command 0x%04x\n", le16_to_cpu(cmd->command));
68     printf("    phy_addr 0x%08x\n", le32_to_cpu(cmd->phy_addr));
69     printf("    cmd_dep 0x%08x\n", le32_to_cpu(cmd->cmd_dep));
70     printf("    res_count 0x%04x\n", le16_to_cpu(cmd->res_count));
71     printf("    xfer_status 0x%04x\n", le16_to_cpu(cmd->xfer_status));
72 }
73 #else
74 static void dump_dbdma_cmd(dbdma_cmd *cmd)
75 {
76 }
77 #endif
78 static void dbdma_cmdptr_load(DBDMA_channel *ch)
79 {
80     DBDMA_DPRINTF("dbdma_cmdptr_load 0x%08x\n",
81                   ch->regs[DBDMA_CMDPTR_LO]);
82     cpu_physical_memory_read(ch->regs[DBDMA_CMDPTR_LO],
83                              &ch->current, sizeof(dbdma_cmd));
84 }
85 
86 static void dbdma_cmdptr_save(DBDMA_channel *ch)
87 {
88     DBDMA_DPRINTF("dbdma_cmdptr_save 0x%08x\n",
89                   ch->regs[DBDMA_CMDPTR_LO]);
90     DBDMA_DPRINTF("xfer_status 0x%08x res_count 0x%04x\n",
91                   le16_to_cpu(ch->current.xfer_status),
92                   le16_to_cpu(ch->current.res_count));
93     cpu_physical_memory_write(ch->regs[DBDMA_CMDPTR_LO],
94                               &ch->current, sizeof(dbdma_cmd));
95 }
96 
97 static void kill_channel(DBDMA_channel *ch)
98 {
99     DBDMA_DPRINTF("kill_channel\n");
100 
101     ch->regs[DBDMA_STATUS] |= DEAD;
102     ch->regs[DBDMA_STATUS] &= ~ACTIVE;
103 
104     qemu_irq_raise(ch->irq);
105 }
106 
107 static void conditional_interrupt(DBDMA_channel *ch)
108 {
109     dbdma_cmd *current = &ch->current;
110     uint16_t intr;
111     uint16_t sel_mask, sel_value;
112     uint32_t status;
113     int cond;
114 
115     DBDMA_DPRINTF("%s\n", __func__);
116 
117     intr = le16_to_cpu(current->command) & INTR_MASK;
118 
119     switch(intr) {
120     case INTR_NEVER:  /* don't interrupt */
121         return;
122     case INTR_ALWAYS: /* always interrupt */
123         qemu_irq_raise(ch->irq);
124         DBDMA_DPRINTF("%s: raise\n", __func__);
125         return;
126     }
127 
128     status = ch->regs[DBDMA_STATUS] & DEVSTAT;
129 
130     sel_mask = (ch->regs[DBDMA_INTR_SEL] >> 16) & 0x0f;
131     sel_value = ch->regs[DBDMA_INTR_SEL] & 0x0f;
132 
133     cond = (status & sel_mask) == (sel_value & sel_mask);
134 
135     switch(intr) {
136     case INTR_IFSET:  /* intr if condition bit is 1 */
137         if (cond) {
138             qemu_irq_raise(ch->irq);
139             DBDMA_DPRINTF("%s: raise\n", __func__);
140         }
141         return;
142     case INTR_IFCLR:  /* intr if condition bit is 0 */
143         if (!cond) {
144             qemu_irq_raise(ch->irq);
145             DBDMA_DPRINTF("%s: raise\n", __func__);
146         }
147         return;
148     }
149 }
150 
151 static int conditional_wait(DBDMA_channel *ch)
152 {
153     dbdma_cmd *current = &ch->current;
154     uint16_t wait;
155     uint16_t sel_mask, sel_value;
156     uint32_t status;
157     int cond;
158 
159     DBDMA_DPRINTF("conditional_wait\n");
160 
161     wait = le16_to_cpu(current->command) & WAIT_MASK;
162 
163     switch(wait) {
164     case WAIT_NEVER:  /* don't wait */
165         return 0;
166     case WAIT_ALWAYS: /* always wait */
167         return 1;
168     }
169 
170     status = ch->regs[DBDMA_STATUS] & DEVSTAT;
171 
172     sel_mask = (ch->regs[DBDMA_WAIT_SEL] >> 16) & 0x0f;
173     sel_value = ch->regs[DBDMA_WAIT_SEL] & 0x0f;
174 
175     cond = (status & sel_mask) == (sel_value & sel_mask);
176 
177     switch(wait) {
178     case WAIT_IFSET:  /* wait if condition bit is 1 */
179         if (cond)
180             return 1;
181         return 0;
182     case WAIT_IFCLR:  /* wait if condition bit is 0 */
183         if (!cond)
184             return 1;
185         return 0;
186     }
187     return 0;
188 }
189 
190 static void next(DBDMA_channel *ch)
191 {
192     uint32_t cp;
193 
194     ch->regs[DBDMA_STATUS] &= ~BT;
195 
196     cp = ch->regs[DBDMA_CMDPTR_LO];
197     ch->regs[DBDMA_CMDPTR_LO] = cp + sizeof(dbdma_cmd);
198     dbdma_cmdptr_load(ch);
199 }
200 
201 static void branch(DBDMA_channel *ch)
202 {
203     dbdma_cmd *current = &ch->current;
204 
205     ch->regs[DBDMA_CMDPTR_LO] = current->cmd_dep;
206     ch->regs[DBDMA_STATUS] |= BT;
207     dbdma_cmdptr_load(ch);
208 }
209 
210 static void conditional_branch(DBDMA_channel *ch)
211 {
212     dbdma_cmd *current = &ch->current;
213     uint16_t br;
214     uint16_t sel_mask, sel_value;
215     uint32_t status;
216     int cond;
217 
218     DBDMA_DPRINTF("conditional_branch\n");
219 
220     /* check if we must branch */
221 
222     br = le16_to_cpu(current->command) & BR_MASK;
223 
224     switch(br) {
225     case BR_NEVER:  /* don't branch */
226         next(ch);
227         return;
228     case BR_ALWAYS: /* always branch */
229         branch(ch);
230         return;
231     }
232 
233     status = ch->regs[DBDMA_STATUS] & DEVSTAT;
234 
235     sel_mask = (ch->regs[DBDMA_BRANCH_SEL] >> 16) & 0x0f;
236     sel_value = ch->regs[DBDMA_BRANCH_SEL] & 0x0f;
237 
238     cond = (status & sel_mask) == (sel_value & sel_mask);
239 
240     switch(br) {
241     case BR_IFSET:  /* branch if condition bit is 1 */
242         if (cond)
243             branch(ch);
244         else
245             next(ch);
246         return;
247     case BR_IFCLR:  /* branch if condition bit is 0 */
248         if (!cond)
249             branch(ch);
250         else
251             next(ch);
252         return;
253     }
254 }
255 
256 static void channel_run(DBDMA_channel *ch);
257 
258 static void dbdma_end(DBDMA_io *io)
259 {
260     DBDMA_channel *ch = io->channel;
261     dbdma_cmd *current = &ch->current;
262 
263     DBDMA_DPRINTF("%s\n", __func__);
264 
265     if (conditional_wait(ch))
266         goto wait;
267 
268     current->xfer_status = cpu_to_le16(ch->regs[DBDMA_STATUS]);
269     current->res_count = cpu_to_le16(io->len);
270     dbdma_cmdptr_save(ch);
271     if (io->is_last)
272         ch->regs[DBDMA_STATUS] &= ~FLUSH;
273 
274     conditional_interrupt(ch);
275     conditional_branch(ch);
276 
277 wait:
278     /* Indicate that we're ready for a new DMA round */
279     ch->io.processing = false;
280 
281     if ((ch->regs[DBDMA_STATUS] & RUN) &&
282         (ch->regs[DBDMA_STATUS] & ACTIVE))
283         channel_run(ch);
284 }
285 
286 static void start_output(DBDMA_channel *ch, int key, uint32_t addr,
287                         uint16_t req_count, int is_last)
288 {
289     DBDMA_DPRINTF("start_output\n");
290 
291     /* KEY_REGS, KEY_DEVICE and KEY_STREAM
292      * are not implemented in the mac-io chip
293      */
294 
295     DBDMA_DPRINTF("addr 0x%x key 0x%x\n", addr, key);
296     if (!addr || key > KEY_STREAM3) {
297         kill_channel(ch);
298         return;
299     }
300 
301     ch->io.addr = addr;
302     ch->io.len = req_count;
303     ch->io.is_last = is_last;
304     ch->io.dma_end = dbdma_end;
305     ch->io.is_dma_out = 1;
306     ch->io.processing = true;
307     if (ch->rw) {
308         ch->rw(&ch->io);
309     }
310 }
311 
312 static void start_input(DBDMA_channel *ch, int key, uint32_t addr,
313                        uint16_t req_count, int is_last)
314 {
315     DBDMA_DPRINTF("start_input\n");
316 
317     /* KEY_REGS, KEY_DEVICE and KEY_STREAM
318      * are not implemented in the mac-io chip
319      */
320 
321     DBDMA_DPRINTF("addr 0x%x key 0x%x\n", addr, key);
322     if (!addr || key > KEY_STREAM3) {
323         kill_channel(ch);
324         return;
325     }
326 
327     ch->io.addr = addr;
328     ch->io.len = req_count;
329     ch->io.is_last = is_last;
330     ch->io.dma_end = dbdma_end;
331     ch->io.is_dma_out = 0;
332     ch->io.processing = true;
333     if (ch->rw) {
334         ch->rw(&ch->io);
335     }
336 }
337 
338 static void load_word(DBDMA_channel *ch, int key, uint32_t addr,
339                      uint16_t len)
340 {
341     dbdma_cmd *current = &ch->current;
342     uint32_t val;
343 
344     DBDMA_DPRINTF("load_word\n");
345 
346     /* only implements KEY_SYSTEM */
347 
348     if (key != KEY_SYSTEM) {
349         printf("DBDMA: LOAD_WORD, unimplemented key %x\n", key);
350         kill_channel(ch);
351         return;
352     }
353 
354     cpu_physical_memory_read(addr, &val, len);
355 
356     if (len == 2)
357         val = (val << 16) | (current->cmd_dep & 0x0000ffff);
358     else if (len == 1)
359         val = (val << 24) | (current->cmd_dep & 0x00ffffff);
360 
361     current->cmd_dep = val;
362 
363     if (conditional_wait(ch))
364         goto wait;
365 
366     current->xfer_status = cpu_to_le16(ch->regs[DBDMA_STATUS]);
367     dbdma_cmdptr_save(ch);
368     ch->regs[DBDMA_STATUS] &= ~FLUSH;
369 
370     conditional_interrupt(ch);
371     next(ch);
372 
373 wait:
374     DBDMA_kick(dbdma_from_ch(ch));
375 }
376 
377 static void store_word(DBDMA_channel *ch, int key, uint32_t addr,
378                       uint16_t len)
379 {
380     dbdma_cmd *current = &ch->current;
381     uint32_t val;
382 
383     DBDMA_DPRINTF("store_word\n");
384 
385     /* only implements KEY_SYSTEM */
386 
387     if (key != KEY_SYSTEM) {
388         printf("DBDMA: STORE_WORD, unimplemented key %x\n", key);
389         kill_channel(ch);
390         return;
391     }
392 
393     val = current->cmd_dep;
394     if (len == 2)
395         val >>= 16;
396     else if (len == 1)
397         val >>= 24;
398 
399     cpu_physical_memory_write(addr, &val, len);
400 
401     if (conditional_wait(ch))
402         goto wait;
403 
404     current->xfer_status = cpu_to_le16(ch->regs[DBDMA_STATUS]);
405     dbdma_cmdptr_save(ch);
406     ch->regs[DBDMA_STATUS] &= ~FLUSH;
407 
408     conditional_interrupt(ch);
409     next(ch);
410 
411 wait:
412     DBDMA_kick(dbdma_from_ch(ch));
413 }
414 
415 static void nop(DBDMA_channel *ch)
416 {
417     dbdma_cmd *current = &ch->current;
418 
419     if (conditional_wait(ch))
420         goto wait;
421 
422     current->xfer_status = cpu_to_le16(ch->regs[DBDMA_STATUS]);
423     dbdma_cmdptr_save(ch);
424 
425     conditional_interrupt(ch);
426     conditional_branch(ch);
427 
428 wait:
429     DBDMA_kick(dbdma_from_ch(ch));
430 }
431 
432 static void stop(DBDMA_channel *ch)
433 {
434     ch->regs[DBDMA_STATUS] &= ~(ACTIVE|DEAD|FLUSH);
435 
436     /* the stop command does not increment command pointer */
437 }
438 
439 static void channel_run(DBDMA_channel *ch)
440 {
441     dbdma_cmd *current = &ch->current;
442     uint16_t cmd, key;
443     uint16_t req_count;
444     uint32_t phy_addr;
445 
446     DBDMA_DPRINTF("channel_run\n");
447     dump_dbdma_cmd(current);
448 
449     /* clear WAKE flag at command fetch */
450 
451     ch->regs[DBDMA_STATUS] &= ~WAKE;
452 
453     cmd = le16_to_cpu(current->command) & COMMAND_MASK;
454 
455     switch (cmd) {
456     case DBDMA_NOP:
457         nop(ch);
458         return;
459 
460     case DBDMA_STOP:
461         stop(ch);
462         return;
463     }
464 
465     key = le16_to_cpu(current->command) & 0x0700;
466     req_count = le16_to_cpu(current->req_count);
467     phy_addr = le32_to_cpu(current->phy_addr);
468 
469     if (key == KEY_STREAM4) {
470         printf("command %x, invalid key 4\n", cmd);
471         kill_channel(ch);
472         return;
473     }
474 
475     switch (cmd) {
476     case OUTPUT_MORE:
477         start_output(ch, key, phy_addr, req_count, 0);
478         return;
479 
480     case OUTPUT_LAST:
481         start_output(ch, key, phy_addr, req_count, 1);
482         return;
483 
484     case INPUT_MORE:
485         start_input(ch, key, phy_addr, req_count, 0);
486         return;
487 
488     case INPUT_LAST:
489         start_input(ch, key, phy_addr, req_count, 1);
490         return;
491     }
492 
493     if (key < KEY_REGS) {
494         printf("command %x, invalid key %x\n", cmd, key);
495         key = KEY_SYSTEM;
496     }
497 
498     /* for LOAD_WORD and STORE_WORD, req_count is on 3 bits
499      * and BRANCH is invalid
500      */
501 
502     req_count = req_count & 0x0007;
503     if (req_count & 0x4) {
504         req_count = 4;
505         phy_addr &= ~3;
506     } else if (req_count & 0x2) {
507         req_count = 2;
508         phy_addr &= ~1;
509     } else
510         req_count = 1;
511 
512     switch (cmd) {
513     case LOAD_WORD:
514         load_word(ch, key, phy_addr, req_count);
515         return;
516 
517     case STORE_WORD:
518         store_word(ch, key, phy_addr, req_count);
519         return;
520     }
521 }
522 
523 static void DBDMA_run(DBDMAState *s)
524 {
525     int channel;
526 
527     for (channel = 0; channel < DBDMA_CHANNELS; channel++) {
528         DBDMA_channel *ch = &s->channels[channel];
529         uint32_t status = ch->regs[DBDMA_STATUS];
530         if (!ch->io.processing && (status & RUN) && (status & ACTIVE)) {
531             channel_run(ch);
532         }
533     }
534 }
535 
536 static void DBDMA_run_bh(void *opaque)
537 {
538     DBDMAState *s = opaque;
539 
540     DBDMA_DPRINTF("DBDMA_run_bh\n");
541 
542     DBDMA_run(s);
543 }
544 
545 void DBDMA_kick(DBDMAState *dbdma)
546 {
547     qemu_bh_schedule(dbdma->bh);
548 }
549 
550 void DBDMA_register_channel(void *dbdma, int nchan, qemu_irq irq,
551                             DBDMA_rw rw, DBDMA_flush flush,
552                             void *opaque)
553 {
554     DBDMAState *s = dbdma;
555     DBDMA_channel *ch = &s->channels[nchan];
556 
557     DBDMA_DPRINTF("DBDMA_register_channel 0x%x\n", nchan);
558 
559     ch->irq = irq;
560     ch->channel = nchan;
561     ch->rw = rw;
562     ch->flush = flush;
563     ch->io.opaque = opaque;
564     ch->io.channel = ch;
565 }
566 
567 static void
568 dbdma_control_write(DBDMA_channel *ch)
569 {
570     uint16_t mask, value;
571     uint32_t status;
572 
573     mask = (ch->regs[DBDMA_CONTROL] >> 16) & 0xffff;
574     value = ch->regs[DBDMA_CONTROL] & 0xffff;
575 
576     value &= (RUN | PAUSE | FLUSH | WAKE | DEVSTAT);
577 
578     status = ch->regs[DBDMA_STATUS];
579 
580     status = (value & mask) | (status & ~mask);
581 
582     if (status & WAKE)
583         status |= ACTIVE;
584     if (status & RUN) {
585         status |= ACTIVE;
586         status &= ~DEAD;
587     }
588     if (status & PAUSE)
589         status &= ~ACTIVE;
590     if ((ch->regs[DBDMA_STATUS] & RUN) && !(status & RUN)) {
591         /* RUN is cleared */
592         status &= ~(ACTIVE|DEAD);
593         if ((status & FLUSH) && ch->flush) {
594             ch->flush(&ch->io);
595             status &= ~FLUSH;
596         }
597     }
598 
599     DBDMA_DPRINTF("    status 0x%08x\n", status);
600 
601     ch->regs[DBDMA_STATUS] = status;
602 
603     if (status & ACTIVE) {
604         DBDMA_kick(dbdma_from_ch(ch));
605     }
606     if ((status & FLUSH) && ch->flush) {
607         ch->flush(&ch->io);
608     }
609 }
610 
611 static void dbdma_write(void *opaque, hwaddr addr,
612                         uint64_t value, unsigned size)
613 {
614     int channel = addr >> DBDMA_CHANNEL_SHIFT;
615     DBDMAState *s = opaque;
616     DBDMA_channel *ch = &s->channels[channel];
617     int reg = (addr - (channel << DBDMA_CHANNEL_SHIFT)) >> 2;
618 
619     DBDMA_DPRINTF("writel 0x" TARGET_FMT_plx " <= 0x%08"PRIx64"\n",
620                   addr, value);
621     DBDMA_DPRINTF("channel 0x%x reg 0x%x\n",
622                   (uint32_t)addr >> DBDMA_CHANNEL_SHIFT, reg);
623 
624     /* cmdptr cannot be modified if channel is ACTIVE */
625 
626     if (reg == DBDMA_CMDPTR_LO && (ch->regs[DBDMA_STATUS] & ACTIVE)) {
627         return;
628     }
629 
630     ch->regs[reg] = value;
631 
632     switch(reg) {
633     case DBDMA_CONTROL:
634         dbdma_control_write(ch);
635         break;
636     case DBDMA_CMDPTR_LO:
637         /* 16-byte aligned */
638         ch->regs[DBDMA_CMDPTR_LO] &= ~0xf;
639         dbdma_cmdptr_load(ch);
640         break;
641     case DBDMA_STATUS:
642     case DBDMA_INTR_SEL:
643     case DBDMA_BRANCH_SEL:
644     case DBDMA_WAIT_SEL:
645         /* nothing to do */
646         break;
647     case DBDMA_XFER_MODE:
648     case DBDMA_CMDPTR_HI:
649     case DBDMA_DATA2PTR_HI:
650     case DBDMA_DATA2PTR_LO:
651     case DBDMA_ADDRESS_HI:
652     case DBDMA_BRANCH_ADDR_HI:
653     case DBDMA_RES1:
654     case DBDMA_RES2:
655     case DBDMA_RES3:
656     case DBDMA_RES4:
657         /* unused */
658         break;
659     }
660 }
661 
662 static uint64_t dbdma_read(void *opaque, hwaddr addr,
663                            unsigned size)
664 {
665     uint32_t value;
666     int channel = addr >> DBDMA_CHANNEL_SHIFT;
667     DBDMAState *s = opaque;
668     DBDMA_channel *ch = &s->channels[channel];
669     int reg = (addr - (channel << DBDMA_CHANNEL_SHIFT)) >> 2;
670 
671     value = ch->regs[reg];
672 
673     DBDMA_DPRINTF("readl 0x" TARGET_FMT_plx " => 0x%08x\n", addr, value);
674     DBDMA_DPRINTF("channel 0x%x reg 0x%x\n",
675                   (uint32_t)addr >> DBDMA_CHANNEL_SHIFT, reg);
676 
677     switch(reg) {
678     case DBDMA_CONTROL:
679         value = 0;
680         break;
681     case DBDMA_STATUS:
682     case DBDMA_CMDPTR_LO:
683     case DBDMA_INTR_SEL:
684     case DBDMA_BRANCH_SEL:
685     case DBDMA_WAIT_SEL:
686         /* nothing to do */
687         break;
688     case DBDMA_XFER_MODE:
689     case DBDMA_CMDPTR_HI:
690     case DBDMA_DATA2PTR_HI:
691     case DBDMA_DATA2PTR_LO:
692     case DBDMA_ADDRESS_HI:
693     case DBDMA_BRANCH_ADDR_HI:
694         /* unused */
695         value = 0;
696         break;
697     case DBDMA_RES1:
698     case DBDMA_RES2:
699     case DBDMA_RES3:
700     case DBDMA_RES4:
701         /* reserved */
702         break;
703     }
704 
705     return value;
706 }
707 
708 static const MemoryRegionOps dbdma_ops = {
709     .read = dbdma_read,
710     .write = dbdma_write,
711     .endianness = DEVICE_LITTLE_ENDIAN,
712     .valid = {
713         .min_access_size = 4,
714         .max_access_size = 4,
715     },
716 };
717 
718 static const VMStateDescription vmstate_dbdma_channel = {
719     .name = "dbdma_channel",
720     .version_id = 0,
721     .minimum_version_id = 0,
722     .minimum_version_id_old = 0,
723     .fields      = (VMStateField[]) {
724         VMSTATE_UINT32_ARRAY(regs, struct DBDMA_channel, DBDMA_REGS),
725         VMSTATE_END_OF_LIST()
726     }
727 };
728 
729 static const VMStateDescription vmstate_dbdma = {
730     .name = "dbdma",
731     .version_id = 2,
732     .minimum_version_id = 2,
733     .minimum_version_id_old = 2,
734     .fields      = (VMStateField[]) {
735         VMSTATE_STRUCT_ARRAY(channels, DBDMAState, DBDMA_CHANNELS, 1,
736                              vmstate_dbdma_channel, DBDMA_channel),
737         VMSTATE_END_OF_LIST()
738     }
739 };
740 
741 static void dbdma_reset(void *opaque)
742 {
743     DBDMAState *s = opaque;
744     int i;
745 
746     for (i = 0; i < DBDMA_CHANNELS; i++)
747         memset(s->channels[i].regs, 0, DBDMA_SIZE);
748 }
749 
750 void* DBDMA_init (MemoryRegion **dbdma_mem)
751 {
752     DBDMAState *s;
753 
754     s = g_malloc0(sizeof(DBDMAState));
755 
756     memory_region_init_io(&s->mem, NULL, &dbdma_ops, s, "dbdma", 0x1000);
757     *dbdma_mem = &s->mem;
758     vmstate_register(NULL, -1, &vmstate_dbdma, s);
759     qemu_register_reset(dbdma_reset, s);
760 
761     s->bh = qemu_bh_new(DBDMA_run_bh, s);
762 
763     return s;
764 }
765