xref: /openbmc/qemu/hw/dma/etraxfs_dma.c (revision 93e0932b)
1 /*
2  * QEMU ETRAX DMA Controller.
3  *
4  * Copyright (c) 2008 Edgar E. Iglesias, Axis Communications AB.
5  *
6  * Permission is hereby granted, free of charge, to any person obtaining a copy
7  * of this software and associated documentation files (the "Software"), to deal
8  * in the Software without restriction, including without limitation the rights
9  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
10  * copies of the Software, and to permit persons to whom the Software is
11  * furnished to do so, subject to the following conditions:
12  *
13  * The above copyright notice and this permission notice shall be included in
14  * all copies or substantial portions of the Software.
15  *
16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
19  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
21  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
22  * THE SOFTWARE.
23  */
24 
25 #include "qemu/osdep.h"
26 #include "hw/hw.h"
27 #include "hw/irq.h"
28 #include "qemu/main-loop.h"
29 #include "sysemu/runstate.h"
30 #include "exec/address-spaces.h"
31 
32 #include "hw/cris/etraxfs_dma.h"
33 
34 #define D(x)
35 
36 #define RW_DATA           (0x0 / 4)
37 #define RW_SAVED_DATA     (0x58 / 4)
38 #define RW_SAVED_DATA_BUF (0x5c / 4)
39 #define RW_GROUP          (0x60 / 4)
40 #define RW_GROUP_DOWN     (0x7c / 4)
41 #define RW_CMD            (0x80 / 4)
42 #define RW_CFG            (0x84 / 4)
43 #define RW_STAT           (0x88 / 4)
44 #define RW_INTR_MASK      (0x8c / 4)
45 #define RW_ACK_INTR       (0x90 / 4)
46 #define R_INTR            (0x94 / 4)
47 #define R_MASKED_INTR     (0x98 / 4)
48 #define RW_STREAM_CMD     (0x9c / 4)
49 
50 #define DMA_REG_MAX       (0x100 / 4)
51 
52 /* descriptors */
53 
54 // ------------------------------------------------------------ dma_descr_group
55 typedef struct dma_descr_group {
56   uint32_t                      next;
57   unsigned                      eol        : 1;
58   unsigned                      tol        : 1;
59   unsigned                      bol        : 1;
60   unsigned                                 : 1;
61   unsigned                      intr       : 1;
62   unsigned                                 : 2;
63   unsigned                      en         : 1;
64   unsigned                                 : 7;
65   unsigned                      dis        : 1;
66   unsigned                      md         : 16;
67   struct dma_descr_group       *up;
68   union {
69     struct dma_descr_context   *context;
70     struct dma_descr_group     *group;
71   }                             down;
72 } dma_descr_group;
73 
74 // ---------------------------------------------------------- dma_descr_context
75 typedef struct dma_descr_context {
76   uint32_t                      next;
77   unsigned                      eol        : 1;
78   unsigned                                 : 3;
79   unsigned                      intr       : 1;
80   unsigned                                 : 1;
81   unsigned                      store_mode : 1;
82   unsigned                      en         : 1;
83   unsigned                                 : 7;
84   unsigned                      dis        : 1;
85   unsigned                      md0        : 16;
86   unsigned                      md1;
87   unsigned                      md2;
88   unsigned                      md3;
89   unsigned                      md4;
90   uint32_t                      saved_data;
91   uint32_t                      saved_data_buf;
92 } dma_descr_context;
93 
94 // ------------------------------------------------------------- dma_descr_data
95 typedef struct dma_descr_data {
96   uint32_t                      next;
97   uint32_t                      buf;
98   unsigned                      eol        : 1;
99   unsigned                                 : 2;
100   unsigned                      out_eop    : 1;
101   unsigned                      intr       : 1;
102   unsigned                      wait       : 1;
103   unsigned                                 : 2;
104   unsigned                                 : 3;
105   unsigned                      in_eop     : 1;
106   unsigned                                 : 4;
107   unsigned                      md         : 16;
108   uint32_t                      after;
109 } dma_descr_data;
110 
111 /* Constants */
112 enum {
113   regk_dma_ack_pkt                         = 0x00000100,
114   regk_dma_anytime                         = 0x00000001,
115   regk_dma_array                           = 0x00000008,
116   regk_dma_burst                           = 0x00000020,
117   regk_dma_client                          = 0x00000002,
118   regk_dma_copy_next                       = 0x00000010,
119   regk_dma_copy_up                         = 0x00000020,
120   regk_dma_data_at_eol                     = 0x00000001,
121   regk_dma_dis_c                           = 0x00000010,
122   regk_dma_dis_g                           = 0x00000020,
123   regk_dma_idle                            = 0x00000001,
124   regk_dma_intern                          = 0x00000004,
125   regk_dma_load_c                          = 0x00000200,
126   regk_dma_load_c_n                        = 0x00000280,
127   regk_dma_load_c_next                     = 0x00000240,
128   regk_dma_load_d                          = 0x00000140,
129   regk_dma_load_g                          = 0x00000300,
130   regk_dma_load_g_down                     = 0x000003c0,
131   regk_dma_load_g_next                     = 0x00000340,
132   regk_dma_load_g_up                       = 0x00000380,
133   regk_dma_next_en                         = 0x00000010,
134   regk_dma_next_pkt                        = 0x00000010,
135   regk_dma_no                              = 0x00000000,
136   regk_dma_only_at_wait                    = 0x00000000,
137   regk_dma_restore                         = 0x00000020,
138   regk_dma_rst                             = 0x00000001,
139   regk_dma_running                         = 0x00000004,
140   regk_dma_rw_cfg_default                  = 0x00000000,
141   regk_dma_rw_cmd_default                  = 0x00000000,
142   regk_dma_rw_intr_mask_default            = 0x00000000,
143   regk_dma_rw_stat_default                 = 0x00000101,
144   regk_dma_rw_stream_cmd_default           = 0x00000000,
145   regk_dma_save_down                       = 0x00000020,
146   regk_dma_save_up                         = 0x00000020,
147   regk_dma_set_reg                         = 0x00000050,
148   regk_dma_set_w_size1                     = 0x00000190,
149   regk_dma_set_w_size2                     = 0x000001a0,
150   regk_dma_set_w_size4                     = 0x000001c0,
151   regk_dma_stopped                         = 0x00000002,
152   regk_dma_store_c                         = 0x00000002,
153   regk_dma_store_descr                     = 0x00000000,
154   regk_dma_store_g                         = 0x00000004,
155   regk_dma_store_md                        = 0x00000001,
156   regk_dma_sw                              = 0x00000008,
157   regk_dma_update_down                     = 0x00000020,
158   regk_dma_yes                             = 0x00000001
159 };
160 
161 enum dma_ch_state
162 {
163 	RST = 1,
164 	STOPPED = 2,
165 	RUNNING = 4
166 };
167 
168 struct fs_dma_channel
169 {
170 	qemu_irq irq;
171 	struct etraxfs_dma_client *client;
172 
173 	/* Internal status.  */
174 	int stream_cmd_src;
175 	enum dma_ch_state state;
176 
177 	unsigned int input : 1;
178 	unsigned int eol : 1;
179 
180 	struct dma_descr_group current_g;
181 	struct dma_descr_context current_c;
182 	struct dma_descr_data current_d;
183 
184 	/* Control registers.  */
185 	uint32_t regs[DMA_REG_MAX];
186 };
187 
188 struct fs_dma_ctrl
189 {
190 	MemoryRegion mmio;
191 	int nr_channels;
192 	struct fs_dma_channel *channels;
193 
194         QEMUBH *bh;
195 };
196 
197 static void DMA_run(void *opaque);
198 static int channel_out_run(struct fs_dma_ctrl *ctrl, int c);
199 
200 static inline uint32_t channel_reg(struct fs_dma_ctrl *ctrl, int c, int reg)
201 {
202 	return ctrl->channels[c].regs[reg];
203 }
204 
205 static inline int channel_stopped(struct fs_dma_ctrl *ctrl, int c)
206 {
207 	return channel_reg(ctrl, c, RW_CFG) & 2;
208 }
209 
210 static inline int channel_en(struct fs_dma_ctrl *ctrl, int c)
211 {
212 	return (channel_reg(ctrl, c, RW_CFG) & 1)
213 		&& ctrl->channels[c].client;
214 }
215 
216 static inline int fs_channel(hwaddr addr)
217 {
218 	/* Every channel has a 0x2000 ctrl register map.  */
219 	return addr >> 13;
220 }
221 
222 #ifdef USE_THIS_DEAD_CODE
223 static void channel_load_g(struct fs_dma_ctrl *ctrl, int c)
224 {
225 	hwaddr addr = channel_reg(ctrl, c, RW_GROUP);
226 
227 	/* Load and decode. FIXME: handle endianness.  */
228     cpu_physical_memory_read(addr, &ctrl->channels[c].current_g,
229                              sizeof(ctrl->channels[c].current_g));
230 }
231 
232 static void dump_c(int ch, struct dma_descr_context *c)
233 {
234 	printf("%s ch=%d\n", __func__, ch);
235 	printf("next=%x\n", c->next);
236 	printf("saved_data=%x\n", c->saved_data);
237 	printf("saved_data_buf=%x\n", c->saved_data_buf);
238 	printf("eol=%x\n", (uint32_t) c->eol);
239 }
240 
241 static void dump_d(int ch, struct dma_descr_data *d)
242 {
243 	printf("%s ch=%d\n", __func__, ch);
244 	printf("next=%x\n", d->next);
245 	printf("buf=%x\n", d->buf);
246 	printf("after=%x\n", d->after);
247 	printf("intr=%x\n", (uint32_t) d->intr);
248 	printf("out_eop=%x\n", (uint32_t) d->out_eop);
249 	printf("in_eop=%x\n", (uint32_t) d->in_eop);
250 	printf("eol=%x\n", (uint32_t) d->eol);
251 }
252 #endif
253 
254 static void channel_load_c(struct fs_dma_ctrl *ctrl, int c)
255 {
256 	hwaddr addr = channel_reg(ctrl, c, RW_GROUP_DOWN);
257 
258 	/* Load and decode. FIXME: handle endianness.  */
259     cpu_physical_memory_read(addr, &ctrl->channels[c].current_c,
260                              sizeof(ctrl->channels[c].current_c));
261 
262 	D(dump_c(c, &ctrl->channels[c].current_c));
263 	/* I guess this should update the current pos.  */
264 	ctrl->channels[c].regs[RW_SAVED_DATA] =
265 		(uint32_t)(unsigned long)ctrl->channels[c].current_c.saved_data;
266 	ctrl->channels[c].regs[RW_SAVED_DATA_BUF] =
267 		(uint32_t)(unsigned long)ctrl->channels[c].current_c.saved_data_buf;
268 }
269 
270 static void channel_load_d(struct fs_dma_ctrl *ctrl, int c)
271 {
272     hwaddr addr = channel_reg(ctrl, c, RW_SAVED_DATA);
273 
274     /* Load and decode. FIXME: handle endianness.  */
275     D(printf("%s ch=%d addr=" HWADDR_FMT_plx "\n", __func__, c, addr));
276     cpu_physical_memory_read(addr, &ctrl->channels[c].current_d,
277                              sizeof(ctrl->channels[c].current_d));
278 
279     D(dump_d(c, &ctrl->channels[c].current_d));
280     ctrl->channels[c].regs[RW_DATA] = addr;
281 }
282 
283 static void channel_store_c(struct fs_dma_ctrl *ctrl, int c)
284 {
285     hwaddr addr = channel_reg(ctrl, c, RW_GROUP_DOWN);
286 
287     /* Encode and store. FIXME: handle endianness.  */
288     D(printf("%s ch=%d addr=" HWADDR_FMT_plx "\n", __func__, c, addr));
289     D(dump_d(c, &ctrl->channels[c].current_d));
290     cpu_physical_memory_write(addr, &ctrl->channels[c].current_c,
291                               sizeof(ctrl->channels[c].current_c));
292 }
293 
294 static void channel_store_d(struct fs_dma_ctrl *ctrl, int c)
295 {
296     hwaddr addr = channel_reg(ctrl, c, RW_SAVED_DATA);
297 
298     /* Encode and store. FIXME: handle endianness.  */
299     D(printf("%s ch=%d addr=" HWADDR_FMT_plx "\n", __func__, c, addr));
300     cpu_physical_memory_write(addr, &ctrl->channels[c].current_d,
301                               sizeof(ctrl->channels[c].current_d));
302 }
303 
304 static inline void channel_stop(struct fs_dma_ctrl *ctrl, int c)
305 {
306 	/* FIXME:  */
307 }
308 
309 static inline void channel_start(struct fs_dma_ctrl *ctrl, int c)
310 {
311 	if (ctrl->channels[c].client)
312 	{
313 		ctrl->channels[c].eol = 0;
314 		ctrl->channels[c].state = RUNNING;
315 		if (!ctrl->channels[c].input)
316 			channel_out_run(ctrl, c);
317 	} else
318 		printf("WARNING: starting DMA ch %d with no client\n", c);
319 
320         qemu_bh_schedule_idle(ctrl->bh);
321 }
322 
323 static void channel_continue(struct fs_dma_ctrl *ctrl, int c)
324 {
325 	if (!channel_en(ctrl, c)
326 	    || channel_stopped(ctrl, c)
327 	    || ctrl->channels[c].state != RUNNING
328 	    /* Only reload the current data descriptor if it has eol set.  */
329 	    || !ctrl->channels[c].current_d.eol) {
330 		D(printf("continue failed ch=%d state=%d stopped=%d en=%d eol=%d\n",
331 			 c, ctrl->channels[c].state,
332 			 channel_stopped(ctrl, c),
333 			 channel_en(ctrl,c),
334 			 ctrl->channels[c].eol));
335 		D(dump_d(c, &ctrl->channels[c].current_d));
336 		return;
337 	}
338 
339 	/* Reload the current descriptor.  */
340 	channel_load_d(ctrl, c);
341 
342 	/* If the current descriptor cleared the eol flag and we had already
343 	   reached eol state, do the continue.  */
344 	if (!ctrl->channels[c].current_d.eol && ctrl->channels[c].eol) {
345 		D(printf("continue %d ok %x\n", c,
346 			 ctrl->channels[c].current_d.next));
347 		ctrl->channels[c].regs[RW_SAVED_DATA] =
348 			(uint32_t)(unsigned long)ctrl->channels[c].current_d.next;
349 		channel_load_d(ctrl, c);
350 		ctrl->channels[c].regs[RW_SAVED_DATA_BUF] =
351 			(uint32_t)(unsigned long)ctrl->channels[c].current_d.buf;
352 
353 		channel_start(ctrl, c);
354 	}
355 	ctrl->channels[c].regs[RW_SAVED_DATA_BUF] =
356 		(uint32_t)(unsigned long)ctrl->channels[c].current_d.buf;
357 }
358 
359 static void channel_stream_cmd(struct fs_dma_ctrl *ctrl, int c, uint32_t v)
360 {
361 	unsigned int cmd = v & ((1 << 10) - 1);
362 
363 	D(printf("%s ch=%d cmd=%x\n",
364 		 __func__, c, cmd));
365 	if (cmd & regk_dma_load_d) {
366 		channel_load_d(ctrl, c);
367 		if (cmd & regk_dma_burst)
368 			channel_start(ctrl, c);
369 	}
370 
371 	if (cmd & regk_dma_load_c) {
372 		channel_load_c(ctrl, c);
373 	}
374 }
375 
376 static void channel_update_irq(struct fs_dma_ctrl *ctrl, int c)
377 {
378 	D(printf("%s %d\n", __func__, c));
379         ctrl->channels[c].regs[R_INTR] &=
380 		~(ctrl->channels[c].regs[RW_ACK_INTR]);
381 
382         ctrl->channels[c].regs[R_MASKED_INTR] =
383 		ctrl->channels[c].regs[R_INTR]
384 		& ctrl->channels[c].regs[RW_INTR_MASK];
385 
386 	D(printf("%s: chan=%d masked_intr=%x\n", __func__,
387 		 c,
388 		 ctrl->channels[c].regs[R_MASKED_INTR]));
389 
390         qemu_set_irq(ctrl->channels[c].irq,
391 		     !!ctrl->channels[c].regs[R_MASKED_INTR]);
392 }
393 
394 static int channel_out_run(struct fs_dma_ctrl *ctrl, int c)
395 {
396 	uint32_t len;
397 	uint32_t saved_data_buf;
398 	unsigned char buf[2 * 1024];
399 
400 	struct dma_context_metadata meta;
401 	bool send_context = true;
402 
403 	if (ctrl->channels[c].eol)
404 		return 0;
405 
406 	do {
407 		bool out_eop;
408 		D(printf("ch=%d buf=%x after=%x\n",
409 			 c,
410 			 (uint32_t)ctrl->channels[c].current_d.buf,
411 			 (uint32_t)ctrl->channels[c].current_d.after));
412 
413 		if (send_context) {
414 			if (ctrl->channels[c].client->client.metadata_push) {
415 				meta.metadata = ctrl->channels[c].current_d.md;
416 				ctrl->channels[c].client->client.metadata_push(
417 					ctrl->channels[c].client->client.opaque,
418 					&meta);
419 			}
420 			send_context = false;
421 		}
422 
423 		channel_load_d(ctrl, c);
424 		saved_data_buf = channel_reg(ctrl, c, RW_SAVED_DATA_BUF);
425 		len = (uint32_t)(unsigned long)
426 			ctrl->channels[c].current_d.after;
427 		len -= saved_data_buf;
428 
429 		if (len > sizeof buf)
430 			len = sizeof buf;
431 		cpu_physical_memory_read (saved_data_buf, buf, len);
432 
433 		out_eop = ((saved_data_buf + len) ==
434 		           ctrl->channels[c].current_d.after) &&
435 			ctrl->channels[c].current_d.out_eop;
436 
437 		D(printf("channel %d pushes %x %u bytes eop=%u\n", c,
438 		         saved_data_buf, len, out_eop));
439 
440 		if (ctrl->channels[c].client->client.push) {
441                         if (len > 0) {
442 				ctrl->channels[c].client->client.push(
443 					ctrl->channels[c].client->client.opaque,
444 					buf, len, out_eop);
445 			}
446 		} else {
447 			printf("WARNING: DMA ch%d dataloss,"
448 			       " no attached client.\n", c);
449 		}
450 
451 		saved_data_buf += len;
452 
453 		if (saved_data_buf == (uint32_t)(unsigned long)
454 				ctrl->channels[c].current_d.after) {
455 			/* Done. Step to next.  */
456 			if (ctrl->channels[c].current_d.out_eop) {
457 				send_context = true;
458 			}
459 			if (ctrl->channels[c].current_d.intr) {
460 				/* data intr.  */
461 				D(printf("signal intr %d eol=%d\n",
462 					len, ctrl->channels[c].current_d.eol));
463 				ctrl->channels[c].regs[R_INTR] |= (1 << 2);
464 				channel_update_irq(ctrl, c);
465 			}
466 			channel_store_d(ctrl, c);
467 			if (ctrl->channels[c].current_d.eol) {
468 				D(printf("channel %d EOL\n", c));
469 				ctrl->channels[c].eol = 1;
470 
471 				/* Mark the context as disabled.  */
472 				ctrl->channels[c].current_c.dis = 1;
473 				channel_store_c(ctrl, c);
474 
475 				channel_stop(ctrl, c);
476 			} else {
477 				ctrl->channels[c].regs[RW_SAVED_DATA] =
478 					(uint32_t)(unsigned long)ctrl->
479 						channels[c].current_d.next;
480 				/* Load new descriptor.  */
481 				channel_load_d(ctrl, c);
482 				saved_data_buf = (uint32_t)(unsigned long)
483 					ctrl->channels[c].current_d.buf;
484 			}
485 
486 			ctrl->channels[c].regs[RW_SAVED_DATA_BUF] =
487 							saved_data_buf;
488 			D(dump_d(c, &ctrl->channels[c].current_d));
489 		}
490 		ctrl->channels[c].regs[RW_SAVED_DATA_BUF] = saved_data_buf;
491 	} while (!ctrl->channels[c].eol);
492 	return 1;
493 }
494 
495 static int channel_in_process(struct fs_dma_ctrl *ctrl, int c,
496 			      unsigned char *buf, int buflen, int eop)
497 {
498 	uint32_t len;
499 	uint32_t saved_data_buf;
500 
501 	if (ctrl->channels[c].eol == 1)
502 		return 0;
503 
504 	channel_load_d(ctrl, c);
505 	saved_data_buf = channel_reg(ctrl, c, RW_SAVED_DATA_BUF);
506 	len = (uint32_t)(unsigned long)ctrl->channels[c].current_d.after;
507 	len -= saved_data_buf;
508 
509 	if (len > buflen)
510 		len = buflen;
511 
512 	cpu_physical_memory_write (saved_data_buf, buf, len);
513 	saved_data_buf += len;
514 
515 	if (saved_data_buf ==
516 	    (uint32_t)(unsigned long)ctrl->channels[c].current_d.after
517 	    || eop) {
518 		uint32_t r_intr = ctrl->channels[c].regs[R_INTR];
519 
520 		D(printf("in dscr end len=%d\n",
521 			 ctrl->channels[c].current_d.after
522 			 - ctrl->channels[c].current_d.buf));
523 		ctrl->channels[c].current_d.after = saved_data_buf;
524 
525 		/* Done. Step to next.  */
526 		if (ctrl->channels[c].current_d.intr) {
527 			/* TODO: signal eop to the client.  */
528 			/* data intr.  */
529 			ctrl->channels[c].regs[R_INTR] |= 3;
530 		}
531 		if (eop) {
532 			ctrl->channels[c].current_d.in_eop = 1;
533 			ctrl->channels[c].regs[R_INTR] |= 8;
534 		}
535 		if (r_intr != ctrl->channels[c].regs[R_INTR])
536 			channel_update_irq(ctrl, c);
537 
538 		channel_store_d(ctrl, c);
539 		D(dump_d(c, &ctrl->channels[c].current_d));
540 
541 		if (ctrl->channels[c].current_d.eol) {
542 			D(printf("channel %d EOL\n", c));
543 			ctrl->channels[c].eol = 1;
544 
545 			/* Mark the context as disabled.  */
546 			ctrl->channels[c].current_c.dis = 1;
547 			channel_store_c(ctrl, c);
548 
549 			channel_stop(ctrl, c);
550 		} else {
551 			ctrl->channels[c].regs[RW_SAVED_DATA] =
552 				(uint32_t)(unsigned long)ctrl->
553 					channels[c].current_d.next;
554 			/* Load new descriptor.  */
555 			channel_load_d(ctrl, c);
556 			saved_data_buf = (uint32_t)(unsigned long)
557 				ctrl->channels[c].current_d.buf;
558 		}
559 	}
560 
561 	ctrl->channels[c].regs[RW_SAVED_DATA_BUF] = saved_data_buf;
562 	return len;
563 }
564 
565 static inline int channel_in_run(struct fs_dma_ctrl *ctrl, int c)
566 {
567 	if (ctrl->channels[c].client->client.pull) {
568 		ctrl->channels[c].client->client.pull(
569 			ctrl->channels[c].client->client.opaque);
570 		return 1;
571 	} else
572 		return 0;
573 }
574 
575 static uint32_t dma_rinvalid (void *opaque, hwaddr addr)
576 {
577     hw_error("Unsupported short raccess. reg=" HWADDR_FMT_plx "\n", addr);
578     return 0;
579 }
580 
581 static uint64_t
582 dma_read(void *opaque, hwaddr addr, unsigned int size)
583 {
584         struct fs_dma_ctrl *ctrl = opaque;
585 	int c;
586 	uint32_t r = 0;
587 
588 	if (size != 4) {
589 		dma_rinvalid(opaque, addr);
590 	}
591 
592 	/* Make addr relative to this channel and bounded to nr regs.  */
593 	c = fs_channel(addr);
594 	addr &= 0xff;
595 	addr >>= 2;
596 	switch (addr)
597 	{
598 		case RW_STAT:
599 			r = ctrl->channels[c].state & 7;
600 			r |= ctrl->channels[c].eol << 5;
601 			r |= ctrl->channels[c].stream_cmd_src << 8;
602 			break;
603 
604 		default:
605 			r = ctrl->channels[c].regs[addr];
606 			D(printf("%s c=%d addr=" HWADDR_FMT_plx "\n",
607 				  __func__, c, addr));
608 			break;
609 	}
610 	return r;
611 }
612 
613 static void
614 dma_winvalid (void *opaque, hwaddr addr, uint32_t value)
615 {
616     hw_error("Unsupported short waccess. reg=" HWADDR_FMT_plx "\n", addr);
617 }
618 
619 static void
620 dma_update_state(struct fs_dma_ctrl *ctrl, int c)
621 {
622 	if (ctrl->channels[c].regs[RW_CFG] & 2)
623 		ctrl->channels[c].state = STOPPED;
624 	if (!(ctrl->channels[c].regs[RW_CFG] & 1))
625 		ctrl->channels[c].state = RST;
626 }
627 
628 static void
629 dma_write(void *opaque, hwaddr addr,
630 	  uint64_t val64, unsigned int size)
631 {
632         struct fs_dma_ctrl *ctrl = opaque;
633 	uint32_t value = val64;
634 	int c;
635 
636 	if (size != 4) {
637 		dma_winvalid(opaque, addr, value);
638 	}
639 
640         /* Make addr relative to this channel and bounded to nr regs.  */
641 	c = fs_channel(addr);
642         addr &= 0xff;
643         addr >>= 2;
644         switch (addr)
645 	{
646 		case RW_DATA:
647 			ctrl->channels[c].regs[addr] = value;
648 			break;
649 
650 		case RW_CFG:
651 			ctrl->channels[c].regs[addr] = value;
652 			dma_update_state(ctrl, c);
653 			break;
654 		case RW_CMD:
655 			/* continue.  */
656 			if (value & ~1)
657 				printf("Invalid store to ch=%d RW_CMD %x\n",
658 				       c, value);
659 			ctrl->channels[c].regs[addr] = value;
660 			channel_continue(ctrl, c);
661 			break;
662 
663 		case RW_SAVED_DATA:
664 		case RW_SAVED_DATA_BUF:
665 		case RW_GROUP:
666 		case RW_GROUP_DOWN:
667 			ctrl->channels[c].regs[addr] = value;
668 			break;
669 
670 		case RW_ACK_INTR:
671 		case RW_INTR_MASK:
672 			ctrl->channels[c].regs[addr] = value;
673 			channel_update_irq(ctrl, c);
674 			if (addr == RW_ACK_INTR)
675 				ctrl->channels[c].regs[RW_ACK_INTR] = 0;
676 			break;
677 
678 		case RW_STREAM_CMD:
679 			if (value & ~1023)
680 				printf("Invalid store to ch=%d "
681 				       "RW_STREAMCMD %x\n",
682 				       c, value);
683 			ctrl->channels[c].regs[addr] = value;
684 			D(printf("stream_cmd ch=%d\n", c));
685 			channel_stream_cmd(ctrl, c, value);
686 			break;
687 
688 	        default:
689 			D(printf("%s c=%d " HWADDR_FMT_plx "\n",
690 				__func__, c, addr));
691 			break;
692         }
693 }
694 
695 static const MemoryRegionOps dma_ops = {
696 	.read = dma_read,
697 	.write = dma_write,
698 	.endianness = DEVICE_NATIVE_ENDIAN,
699 	.valid = {
700 		.min_access_size = 1,
701 		.max_access_size = 4
702 	}
703 };
704 
705 static int etraxfs_dmac_run(void *opaque)
706 {
707 	struct fs_dma_ctrl *ctrl = opaque;
708 	int i;
709 	int p = 0;
710 
711 	for (i = 0;
712 	     i < ctrl->nr_channels;
713 	     i++)
714 	{
715 		if (ctrl->channels[i].state == RUNNING)
716 		{
717 			if (ctrl->channels[i].input) {
718 				p += channel_in_run(ctrl, i);
719 			} else {
720 				p += channel_out_run(ctrl, i);
721 			}
722 		}
723 	}
724 	return p;
725 }
726 
727 int etraxfs_dmac_input(struct etraxfs_dma_client *client,
728 		       void *buf, int len, int eop)
729 {
730 	return channel_in_process(client->ctrl, client->channel,
731 				  buf, len, eop);
732 }
733 
734 /* Connect an IRQ line with a channel.  */
735 void etraxfs_dmac_connect(void *opaque, int c, qemu_irq *line, int input)
736 {
737 	struct fs_dma_ctrl *ctrl = opaque;
738 	ctrl->channels[c].irq = *line;
739 	ctrl->channels[c].input = input;
740 }
741 
742 void etraxfs_dmac_connect_client(void *opaque, int c,
743 				 struct etraxfs_dma_client *cl)
744 {
745 	struct fs_dma_ctrl *ctrl = opaque;
746 	cl->ctrl = ctrl;
747 	cl->channel = c;
748 	ctrl->channels[c].client = cl;
749 }
750 
751 
752 static void DMA_run(void *opaque)
753 {
754     struct fs_dma_ctrl *etraxfs_dmac = opaque;
755     int p = 1;
756 
757     if (runstate_is_running())
758         p = etraxfs_dmac_run(etraxfs_dmac);
759 
760     if (p)
761         qemu_bh_schedule_idle(etraxfs_dmac->bh);
762 }
763 
764 void *etraxfs_dmac_init(hwaddr base, int nr_channels)
765 {
766 	struct fs_dma_ctrl *ctrl = NULL;
767 
768 	ctrl = g_malloc0(sizeof *ctrl);
769 
770         ctrl->bh = qemu_bh_new(DMA_run, ctrl);
771 
772 	ctrl->nr_channels = nr_channels;
773 	ctrl->channels = g_malloc0(sizeof ctrl->channels[0] * nr_channels);
774 
775 	memory_region_init_io(&ctrl->mmio, NULL, &dma_ops, ctrl, "etraxfs-dma",
776 			      nr_channels * 0x2000);
777 	memory_region_add_subregion(get_system_memory(), base, &ctrl->mmio);
778 
779 	return ctrl;
780 }
781