xref: /openbmc/qemu/hw/misc/macio/mac_dbdma.c (revision c16de0d9)
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 
40 #include "qemu/osdep.h"
41 #include "hw/irq.h"
42 #include "hw/ppc/mac_dbdma.h"
43 #include "migration/vmstate.h"
44 #include "qemu/main-loop.h"
45 #include "qemu/module.h"
46 #include "qemu/log.h"
47 #include "sysemu/dma.h"
48 
49 /* debug DBDMA */
50 #define DEBUG_DBDMA 0
51 #define DEBUG_DBDMA_CHANMASK ((1ull << DBDMA_CHANNELS) - 1)
52 
53 #define DBDMA_DPRINTF(fmt, ...) do { \
54     if (DEBUG_DBDMA) { \
55         printf("DBDMA: " fmt , ## __VA_ARGS__); \
56     } \
57 } while (0)
58 
59 #define DBDMA_DPRINTFCH(ch, fmt, ...) do { \
60     if (DEBUG_DBDMA) { \
61         if ((1ul << (ch)->channel) & DEBUG_DBDMA_CHANMASK) { \
62             printf("DBDMA[%02x]: " fmt , (ch)->channel, ## __VA_ARGS__); \
63         } \
64     } \
65 } while (0)
66 
67 /*
68  */
69 
70 static DBDMAState *dbdma_from_ch(DBDMA_channel *ch)
71 {
72     return container_of(ch, DBDMAState, channels[ch->channel]);
73 }
74 
75 #if DEBUG_DBDMA
76 static void dump_dbdma_cmd(DBDMA_channel *ch, dbdma_cmd *cmd)
77 {
78     DBDMA_DPRINTFCH(ch, "dbdma_cmd %p\n", cmd);
79     DBDMA_DPRINTFCH(ch, "    req_count 0x%04x\n", le16_to_cpu(cmd->req_count));
80     DBDMA_DPRINTFCH(ch, "    command 0x%04x\n", le16_to_cpu(cmd->command));
81     DBDMA_DPRINTFCH(ch, "    phy_addr 0x%08x\n", le32_to_cpu(cmd->phy_addr));
82     DBDMA_DPRINTFCH(ch, "    cmd_dep 0x%08x\n", le32_to_cpu(cmd->cmd_dep));
83     DBDMA_DPRINTFCH(ch, "    res_count 0x%04x\n", le16_to_cpu(cmd->res_count));
84     DBDMA_DPRINTFCH(ch, "    xfer_status 0x%04x\n",
85                     le16_to_cpu(cmd->xfer_status));
86 }
87 #else
88 static void dump_dbdma_cmd(DBDMA_channel *ch, dbdma_cmd *cmd)
89 {
90 }
91 #endif
92 static void dbdma_cmdptr_load(DBDMA_channel *ch)
93 {
94     DBDMA_DPRINTFCH(ch, "dbdma_cmdptr_load 0x%08x\n",
95                     ch->regs[DBDMA_CMDPTR_LO]);
96     dma_memory_read(&address_space_memory, ch->regs[DBDMA_CMDPTR_LO],
97                     &ch->current, sizeof(dbdma_cmd), MEMTXATTRS_UNSPECIFIED);
98 }
99 
100 static void dbdma_cmdptr_save(DBDMA_channel *ch)
101 {
102     DBDMA_DPRINTFCH(ch, "-> update 0x%08x stat=0x%08x, res=0x%04x\n",
103                     ch->regs[DBDMA_CMDPTR_LO],
104                     le16_to_cpu(ch->current.xfer_status),
105                     le16_to_cpu(ch->current.res_count));
106     dma_memory_write(&address_space_memory, ch->regs[DBDMA_CMDPTR_LO],
107                      &ch->current, sizeof(dbdma_cmd), MEMTXATTRS_UNSPECIFIED);
108 }
109 
110 static void kill_channel(DBDMA_channel *ch)
111 {
112     DBDMA_DPRINTFCH(ch, "kill_channel\n");
113 
114     ch->regs[DBDMA_STATUS] |= DEAD;
115     ch->regs[DBDMA_STATUS] &= ~ACTIVE;
116 
117     qemu_irq_raise(ch->irq);
118 }
119 
120 static void conditional_interrupt(DBDMA_channel *ch)
121 {
122     dbdma_cmd *current = &ch->current;
123     uint16_t intr;
124     uint16_t sel_mask, sel_value;
125     uint32_t status;
126     int cond;
127 
128     DBDMA_DPRINTFCH(ch, "%s\n", __func__);
129 
130     intr = le16_to_cpu(current->command) & INTR_MASK;
131 
132     switch(intr) {
133     case INTR_NEVER:  /* don't interrupt */
134         return;
135     case INTR_ALWAYS: /* always interrupt */
136         qemu_irq_raise(ch->irq);
137         DBDMA_DPRINTFCH(ch, "%s: raise\n", __func__);
138         return;
139     }
140 
141     status = ch->regs[DBDMA_STATUS] & DEVSTAT;
142 
143     sel_mask = (ch->regs[DBDMA_INTR_SEL] >> 16) & 0x0f;
144     sel_value = ch->regs[DBDMA_INTR_SEL] & 0x0f;
145 
146     cond = (status & sel_mask) == (sel_value & sel_mask);
147 
148     switch(intr) {
149     case INTR_IFSET:  /* intr if condition bit is 1 */
150         if (cond) {
151             qemu_irq_raise(ch->irq);
152             DBDMA_DPRINTFCH(ch, "%s: raise\n", __func__);
153         }
154         return;
155     case INTR_IFCLR:  /* intr if condition bit is 0 */
156         if (!cond) {
157             qemu_irq_raise(ch->irq);
158             DBDMA_DPRINTFCH(ch, "%s: raise\n", __func__);
159         }
160         return;
161     }
162 }
163 
164 static int conditional_wait(DBDMA_channel *ch)
165 {
166     dbdma_cmd *current = &ch->current;
167     uint16_t wait;
168     uint16_t sel_mask, sel_value;
169     uint32_t status;
170     int cond;
171     int res = 0;
172 
173     wait = le16_to_cpu(current->command) & WAIT_MASK;
174     switch(wait) {
175     case WAIT_NEVER:  /* don't wait */
176         return 0;
177     case WAIT_ALWAYS: /* always wait */
178         DBDMA_DPRINTFCH(ch, "  [WAIT_ALWAYS]\n");
179         return 1;
180     }
181 
182     status = ch->regs[DBDMA_STATUS] & DEVSTAT;
183 
184     sel_mask = (ch->regs[DBDMA_WAIT_SEL] >> 16) & 0x0f;
185     sel_value = ch->regs[DBDMA_WAIT_SEL] & 0x0f;
186 
187     cond = (status & sel_mask) == (sel_value & sel_mask);
188 
189     switch(wait) {
190     case WAIT_IFSET:  /* wait if condition bit is 1 */
191         if (cond) {
192             res = 1;
193         }
194         DBDMA_DPRINTFCH(ch, "  [WAIT_IFSET=%d]\n", res);
195         break;
196     case WAIT_IFCLR:  /* wait if condition bit is 0 */
197         if (!cond) {
198             res = 1;
199         }
200         DBDMA_DPRINTFCH(ch, "  [WAIT_IFCLR=%d]\n", res);
201         break;
202     }
203     return res;
204 }
205 
206 static void next(DBDMA_channel *ch)
207 {
208     uint32_t cp;
209 
210     ch->regs[DBDMA_STATUS] &= ~BT;
211 
212     cp = ch->regs[DBDMA_CMDPTR_LO];
213     ch->regs[DBDMA_CMDPTR_LO] = cp + sizeof(dbdma_cmd);
214     dbdma_cmdptr_load(ch);
215 }
216 
217 static void branch(DBDMA_channel *ch)
218 {
219     dbdma_cmd *current = &ch->current;
220 
221     ch->regs[DBDMA_CMDPTR_LO] = le32_to_cpu(current->cmd_dep);
222     ch->regs[DBDMA_STATUS] |= BT;
223     dbdma_cmdptr_load(ch);
224 }
225 
226 static void conditional_branch(DBDMA_channel *ch)
227 {
228     dbdma_cmd *current = &ch->current;
229     uint16_t br;
230     uint16_t sel_mask, sel_value;
231     uint32_t status;
232     int cond;
233 
234     /* check if we must branch */
235 
236     br = le16_to_cpu(current->command) & BR_MASK;
237 
238     switch(br) {
239     case BR_NEVER:  /* don't branch */
240         next(ch);
241         return;
242     case BR_ALWAYS: /* always branch */
243         DBDMA_DPRINTFCH(ch, "  [BR_ALWAYS]\n");
244         branch(ch);
245         return;
246     }
247 
248     status = ch->regs[DBDMA_STATUS] & DEVSTAT;
249 
250     sel_mask = (ch->regs[DBDMA_BRANCH_SEL] >> 16) & 0x0f;
251     sel_value = ch->regs[DBDMA_BRANCH_SEL] & 0x0f;
252 
253     cond = (status & sel_mask) == (sel_value & sel_mask);
254 
255     switch(br) {
256     case BR_IFSET:  /* branch if condition bit is 1 */
257         if (cond) {
258             DBDMA_DPRINTFCH(ch, "  [BR_IFSET = 1]\n");
259             branch(ch);
260         } else {
261             DBDMA_DPRINTFCH(ch, "  [BR_IFSET = 0]\n");
262             next(ch);
263         }
264         return;
265     case BR_IFCLR:  /* branch if condition bit is 0 */
266         if (!cond) {
267             DBDMA_DPRINTFCH(ch, "  [BR_IFCLR = 1]\n");
268             branch(ch);
269         } else {
270             DBDMA_DPRINTFCH(ch, "  [BR_IFCLR = 0]\n");
271             next(ch);
272         }
273         return;
274     }
275 }
276 
277 static void channel_run(DBDMA_channel *ch);
278 
279 static void dbdma_end(DBDMA_io *io)
280 {
281     DBDMA_channel *ch = io->channel;
282     dbdma_cmd *current = &ch->current;
283 
284     DBDMA_DPRINTFCH(ch, "%s\n", __func__);
285 
286     if (conditional_wait(ch))
287         goto wait;
288 
289     current->xfer_status = cpu_to_le16(ch->regs[DBDMA_STATUS]);
290     current->res_count = cpu_to_le16(io->len);
291     dbdma_cmdptr_save(ch);
292     if (io->is_last)
293         ch->regs[DBDMA_STATUS] &= ~FLUSH;
294 
295     conditional_interrupt(ch);
296     conditional_branch(ch);
297 
298 wait:
299     /* Indicate that we're ready for a new DMA round */
300     ch->io.processing = false;
301 
302     if ((ch->regs[DBDMA_STATUS] & RUN) &&
303         (ch->regs[DBDMA_STATUS] & ACTIVE))
304         channel_run(ch);
305 }
306 
307 static void start_output(DBDMA_channel *ch, int key, uint32_t addr,
308                         uint16_t req_count, int is_last)
309 {
310     DBDMA_DPRINTFCH(ch, "start_output\n");
311 
312     /* KEY_REGS, KEY_DEVICE and KEY_STREAM
313      * are not implemented in the mac-io chip
314      */
315 
316     DBDMA_DPRINTFCH(ch, "addr 0x%x key 0x%x\n", addr, key);
317     if (!addr || key > KEY_STREAM3) {
318         kill_channel(ch);
319         return;
320     }
321 
322     ch->io.addr = addr;
323     ch->io.len = req_count;
324     ch->io.is_last = is_last;
325     ch->io.dma_end = dbdma_end;
326     ch->io.is_dma_out = 1;
327     ch->io.processing = true;
328     if (ch->rw) {
329         ch->rw(&ch->io);
330     }
331 }
332 
333 static void start_input(DBDMA_channel *ch, int key, uint32_t addr,
334                        uint16_t req_count, int is_last)
335 {
336     DBDMA_DPRINTFCH(ch, "start_input\n");
337 
338     /* KEY_REGS, KEY_DEVICE and KEY_STREAM
339      * are not implemented in the mac-io chip
340      */
341 
342     DBDMA_DPRINTFCH(ch, "addr 0x%x key 0x%x\n", addr, key);
343     if (!addr || key > KEY_STREAM3) {
344         kill_channel(ch);
345         return;
346     }
347 
348     ch->io.addr = addr;
349     ch->io.len = req_count;
350     ch->io.is_last = is_last;
351     ch->io.dma_end = dbdma_end;
352     ch->io.is_dma_out = 0;
353     ch->io.processing = true;
354     if (ch->rw) {
355         ch->rw(&ch->io);
356     }
357 }
358 
359 static void load_word(DBDMA_channel *ch, int key, uint32_t addr,
360                      uint16_t len)
361 {
362     dbdma_cmd *current = &ch->current;
363 
364     DBDMA_DPRINTFCH(ch, "load_word %d bytes, addr=%08x\n", len, addr);
365 
366     /* only implements KEY_SYSTEM */
367 
368     if (key != KEY_SYSTEM) {
369         printf("DBDMA: LOAD_WORD, unimplemented key %x\n", key);
370         kill_channel(ch);
371         return;
372     }
373 
374     dma_memory_read(&address_space_memory, addr, &current->cmd_dep, len,
375                     MEMTXATTRS_UNSPECIFIED);
376 
377     if (conditional_wait(ch))
378         goto wait;
379 
380     current->xfer_status = cpu_to_le16(ch->regs[DBDMA_STATUS]);
381     dbdma_cmdptr_save(ch);
382     ch->regs[DBDMA_STATUS] &= ~FLUSH;
383 
384     conditional_interrupt(ch);
385     next(ch);
386 
387 wait:
388     DBDMA_kick(dbdma_from_ch(ch));
389 }
390 
391 static void store_word(DBDMA_channel *ch, int key, uint32_t addr,
392                       uint16_t len)
393 {
394     dbdma_cmd *current = &ch->current;
395 
396     DBDMA_DPRINTFCH(ch, "store_word %d bytes, addr=%08x pa=%x\n",
397                     len, addr, le32_to_cpu(current->cmd_dep));
398 
399     /* only implements KEY_SYSTEM */
400 
401     if (key != KEY_SYSTEM) {
402         printf("DBDMA: STORE_WORD, unimplemented key %x\n", key);
403         kill_channel(ch);
404         return;
405     }
406 
407     dma_memory_write(&address_space_memory, addr, &current->cmd_dep, len,
408                      MEMTXATTRS_UNSPECIFIED);
409 
410     if (conditional_wait(ch))
411         goto wait;
412 
413     current->xfer_status = cpu_to_le16(ch->regs[DBDMA_STATUS]);
414     dbdma_cmdptr_save(ch);
415     ch->regs[DBDMA_STATUS] &= ~FLUSH;
416 
417     conditional_interrupt(ch);
418     next(ch);
419 
420 wait:
421     DBDMA_kick(dbdma_from_ch(ch));
422 }
423 
424 static void nop(DBDMA_channel *ch)
425 {
426     dbdma_cmd *current = &ch->current;
427 
428     if (conditional_wait(ch))
429         goto wait;
430 
431     current->xfer_status = cpu_to_le16(ch->regs[DBDMA_STATUS]);
432     dbdma_cmdptr_save(ch);
433 
434     conditional_interrupt(ch);
435     conditional_branch(ch);
436 
437 wait:
438     DBDMA_kick(dbdma_from_ch(ch));
439 }
440 
441 static void stop(DBDMA_channel *ch)
442 {
443     ch->regs[DBDMA_STATUS] &= ~(ACTIVE);
444 
445     /* the stop command does not increment command pointer */
446 }
447 
448 static void channel_run(DBDMA_channel *ch)
449 {
450     dbdma_cmd *current = &ch->current;
451     uint16_t cmd, key;
452     uint16_t req_count;
453     uint32_t phy_addr;
454 
455     DBDMA_DPRINTFCH(ch, "channel_run\n");
456     dump_dbdma_cmd(ch, current);
457 
458     /* clear WAKE flag at command fetch */
459 
460     ch->regs[DBDMA_STATUS] &= ~WAKE;
461 
462     cmd = le16_to_cpu(current->command) & COMMAND_MASK;
463 
464     switch (cmd) {
465     case DBDMA_NOP:
466         nop(ch);
467         return;
468 
469     case DBDMA_STOP:
470         stop(ch);
471         return;
472     }
473 
474     key = le16_to_cpu(current->command) & 0x0700;
475     req_count = le16_to_cpu(current->req_count);
476     phy_addr = le32_to_cpu(current->phy_addr);
477 
478     if (key == KEY_STREAM4) {
479         printf("command %x, invalid key 4\n", cmd);
480         kill_channel(ch);
481         return;
482     }
483 
484     switch (cmd) {
485     case OUTPUT_MORE:
486         DBDMA_DPRINTFCH(ch, "* OUTPUT_MORE *\n");
487         start_output(ch, key, phy_addr, req_count, 0);
488         return;
489 
490     case OUTPUT_LAST:
491         DBDMA_DPRINTFCH(ch, "* OUTPUT_LAST *\n");
492         start_output(ch, key, phy_addr, req_count, 1);
493         return;
494 
495     case INPUT_MORE:
496         DBDMA_DPRINTFCH(ch, "* INPUT_MORE *\n");
497         start_input(ch, key, phy_addr, req_count, 0);
498         return;
499 
500     case INPUT_LAST:
501         DBDMA_DPRINTFCH(ch, "* INPUT_LAST *\n");
502         start_input(ch, key, phy_addr, req_count, 1);
503         return;
504     }
505 
506     if (key < KEY_REGS) {
507         printf("command %x, invalid key %x\n", cmd, key);
508         key = KEY_SYSTEM;
509     }
510 
511     /* for LOAD_WORD and STORE_WORD, req_count is on 3 bits
512      * and BRANCH is invalid
513      */
514 
515     req_count = req_count & 0x0007;
516     if (req_count & 0x4) {
517         req_count = 4;
518         phy_addr &= ~3;
519     } else if (req_count & 0x2) {
520         req_count = 2;
521         phy_addr &= ~1;
522     } else
523         req_count = 1;
524 
525     switch (cmd) {
526     case LOAD_WORD:
527         DBDMA_DPRINTFCH(ch, "* LOAD_WORD *\n");
528         load_word(ch, key, phy_addr, req_count);
529         return;
530 
531     case STORE_WORD:
532         DBDMA_DPRINTFCH(ch, "* STORE_WORD *\n");
533         store_word(ch, key, phy_addr, req_count);
534         return;
535     }
536 }
537 
538 static void DBDMA_run(DBDMAState *s)
539 {
540     int channel;
541 
542     for (channel = 0; channel < DBDMA_CHANNELS; channel++) {
543         DBDMA_channel *ch = &s->channels[channel];
544         uint32_t status = ch->regs[DBDMA_STATUS];
545         if (!ch->io.processing && (status & RUN) && (status & ACTIVE)) {
546             channel_run(ch);
547         }
548     }
549 }
550 
551 static void DBDMA_run_bh(void *opaque)
552 {
553     DBDMAState *s = opaque;
554 
555     DBDMA_DPRINTF("-> DBDMA_run_bh\n");
556     DBDMA_run(s);
557     DBDMA_DPRINTF("<- DBDMA_run_bh\n");
558 }
559 
560 void DBDMA_kick(DBDMAState *dbdma)
561 {
562     qemu_bh_schedule(dbdma->bh);
563 }
564 
565 void DBDMA_register_channel(void *dbdma, int nchan, qemu_irq irq,
566                             DBDMA_rw rw, DBDMA_flush flush,
567                             void *opaque)
568 {
569     DBDMAState *s = dbdma;
570     DBDMA_channel *ch = &s->channels[nchan];
571 
572     DBDMA_DPRINTFCH(ch, "DBDMA_register_channel 0x%x\n", nchan);
573 
574     assert(rw);
575     assert(flush);
576 
577     ch->irq = irq;
578     ch->rw = rw;
579     ch->flush = flush;
580     ch->io.opaque = opaque;
581 }
582 
583 static void dbdma_control_write(DBDMA_channel *ch)
584 {
585     uint16_t mask, value;
586     uint32_t status;
587     bool do_flush = false;
588 
589     mask = (ch->regs[DBDMA_CONTROL] >> 16) & 0xffff;
590     value = ch->regs[DBDMA_CONTROL] & 0xffff;
591 
592     /* This is the status register which we'll update
593      * appropriately and store back
594      */
595     status = ch->regs[DBDMA_STATUS];
596 
597     /* RUN and PAUSE are bits under SW control only
598      * FLUSH and WAKE are set by SW and cleared by HW
599      * DEAD, ACTIVE and BT are only under HW control
600      *
601      * We handle ACTIVE separately at the end of the
602      * logic to ensure all cases are covered.
603      */
604 
605     /* Setting RUN will tentatively activate the channel
606      */
607     if ((mask & RUN) && (value & RUN)) {
608         status |= RUN;
609         DBDMA_DPRINTFCH(ch, " Setting RUN !\n");
610     }
611 
612     /* Clearing RUN 1->0 will stop the channel */
613     if ((mask & RUN) && !(value & RUN)) {
614         /* This has the side effect of clearing the DEAD bit */
615         status &= ~(DEAD | RUN);
616         DBDMA_DPRINTFCH(ch, " Clearing RUN !\n");
617     }
618 
619     /* Setting WAKE wakes up an idle channel if it's running
620      *
621      * Note: The doc doesn't say so but assume that only works
622      * on a channel whose RUN bit is set.
623      *
624      * We set WAKE in status, it's not terribly useful as it will
625      * be cleared on the next command fetch but it seems to mimmic
626      * the HW behaviour and is useful for the way we handle
627      * ACTIVE further down.
628      */
629     if ((mask & WAKE) && (value & WAKE) && (status & RUN)) {
630         status |= WAKE;
631         DBDMA_DPRINTFCH(ch, " Setting WAKE !\n");
632     }
633 
634     /* PAUSE being set will deactivate (or prevent activation)
635      * of the channel. We just copy it over for now, ACTIVE will
636      * be re-evaluated later.
637      */
638     if (mask & PAUSE) {
639         status = (status & ~PAUSE) | (value & PAUSE);
640         DBDMA_DPRINTFCH(ch, " %sing PAUSE !\n",
641                         (value & PAUSE) ? "sett" : "clear");
642     }
643 
644     /* FLUSH is its own thing */
645     if ((mask & FLUSH) && (value & FLUSH))  {
646         DBDMA_DPRINTFCH(ch, " Setting FLUSH !\n");
647         /* We set flush directly in the status register, we do *NOT*
648          * set it in "status" so that it gets naturally cleared when
649          * we update the status register further down. That way it
650          * will be set only during the HW flush operation so it is
651          * visible to any completions happening during that time.
652          */
653         ch->regs[DBDMA_STATUS] |= FLUSH;
654         do_flush = true;
655     }
656 
657     /* If either RUN or PAUSE is clear, so should ACTIVE be,
658      * otherwise, ACTIVE will be set if we modified RUN, PAUSE or
659      * set WAKE. That means that PAUSE was just cleared, RUN was
660      * just set or WAKE was just set.
661      */
662     if ((status & PAUSE) || !(status & RUN)) {
663         status &= ~ACTIVE;
664         DBDMA_DPRINTFCH(ch, "  -> ACTIVE down !\n");
665 
666         /* We stopped processing, we want the underlying HW command
667          * to complete *before* we clear the ACTIVE bit. Otherwise
668          * we can get into a situation where the command status will
669          * have RUN or ACTIVE not set which is going to confuse the
670          * MacOS driver.
671          */
672         do_flush = true;
673     } else if (mask & (RUN | PAUSE)) {
674         status |= ACTIVE;
675         DBDMA_DPRINTFCH(ch, " -> ACTIVE up !\n");
676     } else if ((mask & WAKE) && (value & WAKE)) {
677         status |= ACTIVE;
678         DBDMA_DPRINTFCH(ch, " -> ACTIVE up !\n");
679     }
680 
681     DBDMA_DPRINTFCH(ch, " new status=0x%08x\n", status);
682 
683     /* If we need to flush the underlying HW, do it now, this happens
684      * both on FLUSH commands and when stopping the channel for safety.
685      */
686     if (do_flush && ch->flush) {
687         ch->flush(&ch->io);
688     }
689 
690     /* Finally update the status register image */
691     ch->regs[DBDMA_STATUS] = status;
692 
693     /* If active, make sure the BH gets to run */
694     if (status & ACTIVE) {
695         DBDMA_kick(dbdma_from_ch(ch));
696     }
697 }
698 
699 static void dbdma_write(void *opaque, hwaddr addr,
700                         uint64_t value, unsigned size)
701 {
702     int channel = addr >> DBDMA_CHANNEL_SHIFT;
703     DBDMAState *s = opaque;
704     DBDMA_channel *ch = &s->channels[channel];
705     int reg = (addr - (channel << DBDMA_CHANNEL_SHIFT)) >> 2;
706 
707     DBDMA_DPRINTFCH(ch, "writel 0x" HWADDR_FMT_plx " <= 0x%08"PRIx64"\n",
708                     addr, value);
709     DBDMA_DPRINTFCH(ch, "channel 0x%x reg 0x%x\n",
710                     (uint32_t)addr >> DBDMA_CHANNEL_SHIFT, reg);
711 
712     /* cmdptr cannot be modified if channel is ACTIVE */
713 
714     if (reg == DBDMA_CMDPTR_LO && (ch->regs[DBDMA_STATUS] & ACTIVE)) {
715         return;
716     }
717 
718     ch->regs[reg] = value;
719 
720     switch(reg) {
721     case DBDMA_CONTROL:
722         dbdma_control_write(ch);
723         break;
724     case DBDMA_CMDPTR_LO:
725         /* 16-byte aligned */
726         ch->regs[DBDMA_CMDPTR_LO] &= ~0xf;
727         dbdma_cmdptr_load(ch);
728         break;
729     case DBDMA_STATUS:
730     case DBDMA_INTR_SEL:
731     case DBDMA_BRANCH_SEL:
732     case DBDMA_WAIT_SEL:
733         /* nothing to do */
734         break;
735     case DBDMA_XFER_MODE:
736     case DBDMA_CMDPTR_HI:
737     case DBDMA_DATA2PTR_HI:
738     case DBDMA_DATA2PTR_LO:
739     case DBDMA_ADDRESS_HI:
740     case DBDMA_BRANCH_ADDR_HI:
741     case DBDMA_RES1:
742     case DBDMA_RES2:
743     case DBDMA_RES3:
744     case DBDMA_RES4:
745         /* unused */
746         break;
747     }
748 }
749 
750 static uint64_t dbdma_read(void *opaque, hwaddr addr,
751                            unsigned size)
752 {
753     uint32_t value;
754     int channel = addr >> DBDMA_CHANNEL_SHIFT;
755     DBDMAState *s = opaque;
756     DBDMA_channel *ch = &s->channels[channel];
757     int reg = (addr - (channel << DBDMA_CHANNEL_SHIFT)) >> 2;
758 
759     value = ch->regs[reg];
760 
761     switch(reg) {
762     case DBDMA_CONTROL:
763         value = ch->regs[DBDMA_STATUS];
764         break;
765     case DBDMA_STATUS:
766     case DBDMA_CMDPTR_LO:
767     case DBDMA_INTR_SEL:
768     case DBDMA_BRANCH_SEL:
769     case DBDMA_WAIT_SEL:
770         /* nothing to do */
771         break;
772     case DBDMA_XFER_MODE:
773     case DBDMA_CMDPTR_HI:
774     case DBDMA_DATA2PTR_HI:
775     case DBDMA_DATA2PTR_LO:
776     case DBDMA_ADDRESS_HI:
777     case DBDMA_BRANCH_ADDR_HI:
778         /* unused */
779         value = 0;
780         break;
781     case DBDMA_RES1:
782     case DBDMA_RES2:
783     case DBDMA_RES3:
784     case DBDMA_RES4:
785         /* reserved */
786         break;
787     }
788 
789     DBDMA_DPRINTFCH(ch, "readl 0x" HWADDR_FMT_plx " => 0x%08x\n", addr, value);
790     DBDMA_DPRINTFCH(ch, "channel 0x%x reg 0x%x\n",
791                     (uint32_t)addr >> DBDMA_CHANNEL_SHIFT, reg);
792 
793     return value;
794 }
795 
796 static const MemoryRegionOps dbdma_ops = {
797     .read = dbdma_read,
798     .write = dbdma_write,
799     .endianness = DEVICE_LITTLE_ENDIAN,
800     .valid = {
801         .min_access_size = 4,
802         .max_access_size = 4,
803     },
804 };
805 
806 static const VMStateDescription vmstate_dbdma_io = {
807     .name = "dbdma_io",
808     .version_id = 0,
809     .minimum_version_id = 0,
810     .fields = (const VMStateField[]) {
811         VMSTATE_UINT64(addr, struct DBDMA_io),
812         VMSTATE_INT32(len, struct DBDMA_io),
813         VMSTATE_INT32(is_last, struct DBDMA_io),
814         VMSTATE_INT32(is_dma_out, struct DBDMA_io),
815         VMSTATE_BOOL(processing, struct DBDMA_io),
816         VMSTATE_END_OF_LIST()
817     }
818 };
819 
820 static const VMStateDescription vmstate_dbdma_cmd = {
821     .name = "dbdma_cmd",
822     .version_id = 0,
823     .minimum_version_id = 0,
824     .fields = (const VMStateField[]) {
825         VMSTATE_UINT16(req_count, dbdma_cmd),
826         VMSTATE_UINT16(command, dbdma_cmd),
827         VMSTATE_UINT32(phy_addr, dbdma_cmd),
828         VMSTATE_UINT32(cmd_dep, dbdma_cmd),
829         VMSTATE_UINT16(res_count, dbdma_cmd),
830         VMSTATE_UINT16(xfer_status, dbdma_cmd),
831         VMSTATE_END_OF_LIST()
832     }
833 };
834 
835 static const VMStateDescription vmstate_dbdma_channel = {
836     .name = "dbdma_channel",
837     .version_id = 1,
838     .minimum_version_id = 1,
839     .fields = (const VMStateField[]) {
840         VMSTATE_UINT32_ARRAY(regs, struct DBDMA_channel, DBDMA_REGS),
841         VMSTATE_STRUCT(io, struct DBDMA_channel, 0, vmstate_dbdma_io, DBDMA_io),
842         VMSTATE_STRUCT(current, struct DBDMA_channel, 0, vmstate_dbdma_cmd,
843                        dbdma_cmd),
844         VMSTATE_END_OF_LIST()
845     }
846 };
847 
848 static const VMStateDescription vmstate_dbdma = {
849     .name = "dbdma",
850     .version_id = 3,
851     .minimum_version_id = 3,
852     .fields = (const VMStateField[]) {
853         VMSTATE_STRUCT_ARRAY(channels, DBDMAState, DBDMA_CHANNELS, 1,
854                              vmstate_dbdma_channel, DBDMA_channel),
855         VMSTATE_END_OF_LIST()
856     }
857 };
858 
859 static void mac_dbdma_reset(DeviceState *d)
860 {
861     DBDMAState *s = MAC_DBDMA(d);
862     int i;
863 
864     for (i = 0; i < DBDMA_CHANNELS; i++) {
865         memset(s->channels[i].regs, 0, DBDMA_SIZE);
866     }
867 }
868 
869 static void dbdma_unassigned_rw(DBDMA_io *io)
870 {
871     DBDMA_channel *ch = io->channel;
872     dbdma_cmd *current = &ch->current;
873     uint16_t cmd;
874     qemu_log_mask(LOG_GUEST_ERROR, "%s: use of unassigned channel %d\n",
875                   __func__, ch->channel);
876     ch->io.processing = false;
877 
878     cmd = le16_to_cpu(current->command) & COMMAND_MASK;
879     if (cmd == OUTPUT_MORE || cmd == OUTPUT_LAST ||
880         cmd == INPUT_MORE || cmd == INPUT_LAST) {
881         current->xfer_status = cpu_to_le16(ch->regs[DBDMA_STATUS]);
882         current->res_count = cpu_to_le16(io->len);
883         dbdma_cmdptr_save(ch);
884     }
885 }
886 
887 static void dbdma_unassigned_flush(DBDMA_io *io)
888 {
889     DBDMA_channel *ch = io->channel;
890     qemu_log_mask(LOG_GUEST_ERROR, "%s: use of unassigned channel %d\n",
891                   __func__, ch->channel);
892 }
893 
894 static void mac_dbdma_init(Object *obj)
895 {
896     SysBusDevice *sbd = SYS_BUS_DEVICE(obj);
897     DBDMAState *s = MAC_DBDMA(obj);
898     int i;
899 
900     for (i = 0; i < DBDMA_CHANNELS; i++) {
901         DBDMA_channel *ch = &s->channels[i];
902 
903         ch->rw = dbdma_unassigned_rw;
904         ch->flush = dbdma_unassigned_flush;
905         ch->channel = i;
906         ch->io.channel = ch;
907     }
908 
909     memory_region_init_io(&s->mem, obj, &dbdma_ops, s, "dbdma", 0x1000);
910     sysbus_init_mmio(sbd, &s->mem);
911 }
912 
913 static void mac_dbdma_realize(DeviceState *dev, Error **errp)
914 {
915     DBDMAState *s = MAC_DBDMA(dev);
916 
917     s->bh = qemu_bh_new_guarded(DBDMA_run_bh, s, &dev->mem_reentrancy_guard);
918 }
919 
920 static void mac_dbdma_class_init(ObjectClass *oc, void *data)
921 {
922     DeviceClass *dc = DEVICE_CLASS(oc);
923 
924     dc->realize = mac_dbdma_realize;
925     dc->reset = mac_dbdma_reset;
926     dc->vmsd = &vmstate_dbdma;
927 }
928 
929 static const TypeInfo mac_dbdma_type_info = {
930     .name = TYPE_MAC_DBDMA,
931     .parent = TYPE_SYS_BUS_DEVICE,
932     .instance_size = sizeof(DBDMAState),
933     .instance_init = mac_dbdma_init,
934     .class_init = mac_dbdma_class_init
935 };
936 
937 static void mac_dbdma_register_types(void)
938 {
939     type_register_static(&mac_dbdma_type_info);
940 }
941 
942 type_init(mac_dbdma_register_types)
943