xref: /netbsd-src/sys/arch/next68k/dev/nextdma.c (revision 17dd36da8292193180754d5047c0926dbb56818c)
1 /*	$NetBSD: nextdma.c,v 1.23 2001/04/02 05:29:43 dbj Exp $	*/
2 /*
3  * Copyright (c) 1998 Darrin B. Jewell
4  * All rights reserved.
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
9  * 1. Redistributions of source code must retain the above copyright
10  *    notice, this list of conditions and the following disclaimer.
11  * 2. Redistributions in binary form must reproduce the above copyright
12  *    notice, this list of conditions and the following disclaimer in the
13  *    documentation and/or other materials provided with the distribution.
14  * 3. All advertising materials mentioning features or use of this software
15  *    must display the following acknowledgement:
16  *      This product includes software developed by Darrin B. Jewell
17  * 4. The name of the author may not be used to endorse or promote products
18  *    derived from this software without specific prior written permission
19  *
20  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
21  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
22  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
23  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
24  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
25  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
26  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
27  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
28  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
29  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30  */
31 
32 #include <sys/param.h>
33 #include <sys/systm.h>
34 #include <sys/mbuf.h>
35 #include <sys/syslog.h>
36 #include <sys/socket.h>
37 #include <sys/device.h>
38 #include <sys/malloc.h>
39 #include <sys/ioctl.h>
40 #include <sys/errno.h>
41 
42 #include <machine/autoconf.h>
43 #include <machine/cpu.h>
44 #include <machine/intr.h>
45 
46 #include <m68k/cacheops.h>
47 
48 #include <next68k/next68k/isr.h>
49 
50 #define _NEXT68K_BUS_DMA_PRIVATE
51 #include <machine/bus.h>
52 
53 #include "nextdmareg.h"
54 #include "nextdmavar.h"
55 
56 #if 1
57 #define ND_DEBUG
58 #endif
59 
60 #if defined(ND_DEBUG)
61 int nextdma_debug = 0;
62 #define DPRINTF(x) if (nextdma_debug) printf x;
63 #else
64 #define DPRINTF(x)
65 #endif
66 
67 void next_dmamap_sync __P((bus_dma_tag_t, bus_dmamap_t, bus_addr_t,
68                        bus_size_t, int));
69 int next_dma_continue __P((struct nextdma_config *));
70 void next_dma_rotate __P((struct nextdma_config *));
71 
72 void next_dma_setup_cont_regs __P((struct nextdma_config *));
73 void next_dma_setup_curr_regs __P((struct nextdma_config *));
74 
75 void
76 nextdma_config(nd)
77 	struct nextdma_config *nd;
78 {
79 	/* Initialize the dma_tag. As a hack, we currently
80 	 * put the dma tag in the structure itself.  It shouldn't be there.
81 	 */
82 
83 	{
84 		bus_dma_tag_t t;
85 		t = &nd->_nd_dmat;
86 		t->_cookie = nd;
87 		t->_dmamap_create = _bus_dmamap_create;
88 		t->_dmamap_destroy = _bus_dmamap_destroy;
89 		t->_dmamap_load = _bus_dmamap_load_direct;
90 		t->_dmamap_load_mbuf = _bus_dmamap_load_mbuf_direct;
91 		t->_dmamap_load_uio = _bus_dmamap_load_uio_direct;
92 		t->_dmamap_load_raw = _bus_dmamap_load_raw_direct;
93 		t->_dmamap_unload = _bus_dmamap_unload;
94 		t->_dmamap_sync = _bus_dmamap_sync;
95 
96 		t->_dmamem_alloc = _bus_dmamem_alloc;
97 		t->_dmamem_free = _bus_dmamem_free;
98 		t->_dmamem_map = _bus_dmamem_map;
99 		t->_dmamem_unmap = _bus_dmamem_unmap;
100 		t->_dmamem_mmap = _bus_dmamem_mmap;
101 
102 		nd->nd_dmat = t;
103 	}
104 
105 	nextdma_init(nd);
106 
107 	isrlink_autovec(nextdma_intr, nd, NEXT_I_IPL(nd->nd_intr), 10);
108 	INTR_ENABLE(nd->nd_intr);
109 }
110 
111 void
112 nextdma_init(nd)
113 	struct nextdma_config *nd;
114 {
115 #ifdef ND_DEBUG
116 	if (nextdma_debug) {
117 		char sbuf[256];
118 
119 		bitmask_snprintf(NEXT_I_BIT(nd->nd_intr), NEXT_INTR_BITS,
120 				 sbuf, sizeof(sbuf));
121 		printf("DMA init ipl (%ld) intr(0x%s)\n",
122 			NEXT_I_IPL(nd->nd_intr), sbuf);
123 	}
124 #endif
125 
126 	nd->_nd_map = NULL;
127 	nd->_nd_idx = 0;
128 	nd->_nd_map_cont = NULL;
129 	nd->_nd_idx_cont = 0;
130 
131 	bus_space_write_4(nd->nd_bst, nd->nd_bsh, DD_CSR, 0);
132 	bus_space_write_4(nd->nd_bst, nd->nd_bsh, DD_CSR,
133 			DMACSR_RESET | DMACSR_INITBUF);
134 
135 	next_dma_setup_curr_regs(nd);
136 	next_dma_setup_cont_regs(nd);
137 
138 #if defined(DIAGNOSTIC)
139 	{
140 		u_long state;
141 		state = bus_space_read_4(nd->nd_bst, nd->nd_bsh, DD_CSR);
142 
143 #if 1
144 	/* mourning (a 25Mhz 68040 mono slab) appears to set BUSEXC
145 	 * milo (a 25Mhz 68040 mono cube) didn't have this problem
146 	 * Darrin B. Jewell <jewell@mit.edu>  Mon May 25 07:53:05 1998
147 	 */
148     state &= (DMACSR_COMPLETE | DMACSR_SUPDATE | DMACSR_ENABLE);
149 #else
150     state &= (DMACSR_BUSEXC | DMACSR_COMPLETE |
151               DMACSR_SUPDATE | DMACSR_ENABLE);
152 #endif
153 		if (state) {
154 			next_dma_print(nd);
155 			panic("DMA did not reset");
156 		}
157 	}
158 #endif
159 }
160 
161 
162 void
163 nextdma_reset(nd)
164 	struct nextdma_config *nd;
165 {
166 	int s;
167 	s = spldma();
168 
169 	DPRINTF(("DMA reset\n"));
170 
171 #if (defined(ND_DEBUG))
172 	if (nextdma_debug) next_dma_print(nd);
173 #endif
174 
175 	/* @@@ clean up dma maps */
176 
177 	nextdma_init(nd);
178 	splx(s);
179 }
180 
181 /****************************************************************/
182 
183 
184 /* Call the completed and continue callbacks to try to fill
185  * in the dma continue buffers.
186  */
187 void
188 next_dma_rotate(nd)
189 	struct nextdma_config *nd;
190 {
191 
192 	DPRINTF(("DMA next_dma_rotate()\n"));
193 
194 	/* Rotate the continue map into the current map */
195 	nd->_nd_map = nd->_nd_map_cont;
196 	nd->_nd_idx = nd->_nd_idx_cont;
197 
198 	if ((!nd->_nd_map_cont) ||
199 			((nd->_nd_map_cont) &&
200 					(++nd->_nd_idx_cont >= nd->_nd_map_cont->dm_nsegs))) {
201 		if (nd->nd_continue_cb) {
202 			nd->_nd_map_cont = (*nd->nd_continue_cb)(nd->nd_cb_arg);
203 		} else {
204 			nd->_nd_map_cont = 0;
205 		}
206 		nd->_nd_idx_cont = 0;
207 	}
208 
209 #ifdef DIAGNOSTIC
210 	if (nd->_nd_map) {
211 		nd->_nd_map->dm_segs[nd->_nd_idx].ds_xfer_len = 666666666;
212 	}
213 #endif
214 
215 #ifdef DIAGNOSTIC
216 	if (nd->_nd_map_cont) {
217 		if (!DMA_BEGINALIGNED(nd->_nd_map_cont->dm_segs[nd->_nd_idx_cont].ds_addr)) {
218 			next_dma_print(nd);
219 			panic("DMA request unaligned at start\n");
220 		}
221 		if (!DMA_ENDALIGNED(nd->_nd_map_cont->dm_segs[nd->_nd_idx_cont].ds_addr +
222 				nd->_nd_map_cont->dm_segs[nd->_nd_idx_cont].ds_len)) {
223 			next_dma_print(nd);
224 			panic("DMA request unaligned at end\n");
225 		}
226 	}
227 #endif
228 
229 }
230 
231 void
232 next_dma_setup_cont_regs(nd)
233 	struct nextdma_config *nd;
234 {
235 	bus_addr_t dd_start;
236 	bus_addr_t dd_stop;
237 	bus_addr_t dd_saved_start;
238 	bus_addr_t dd_saved_stop;
239 
240 	DPRINTF(("DMA next_dma_setup_regs()\n"));
241 
242 	if (nd->_nd_map_cont) {
243 		dd_start = nd->_nd_map_cont->dm_segs[nd->_nd_idx_cont].ds_addr;
244 		dd_stop  = (nd->_nd_map_cont->dm_segs[nd->_nd_idx_cont].ds_addr +
245 				nd->_nd_map_cont->dm_segs[nd->_nd_idx_cont].ds_len);
246 
247 		if (nd->nd_intr == NEXT_I_ENETX_DMA) {
248 			dd_stop |= 0x80000000;		/* Ethernet transmit needs secret magic */
249 		}
250 	} else {
251 		dd_start = 0xdeadbeef;
252 		dd_stop = 0xdeadbeef;
253 	}
254 
255 	dd_saved_start = dd_start;
256 	dd_saved_stop  = dd_stop;
257 
258 	bus_space_write_4(nd->nd_bst, nd->nd_bsh, DD_START, dd_start);
259 	bus_space_write_4(nd->nd_bst, nd->nd_bsh, DD_STOP, dd_stop);
260 	bus_space_write_4(nd->nd_bst, nd->nd_bsh, DD_SAVED_START, dd_saved_start);
261 	bus_space_write_4(nd->nd_bst, nd->nd_bsh, DD_SAVED_STOP, dd_saved_stop);
262 
263 #ifdef DIAGNOSTIC
264 	if ((bus_space_read_4(nd->nd_bst, nd->nd_bsh, DD_START) != dd_start) ||
265 			(bus_space_read_4(nd->nd_bst, nd->nd_bsh, DD_STOP) != dd_stop) ||
266 			(bus_space_read_4(nd->nd_bst, nd->nd_bsh, DD_SAVED_START) != dd_saved_start) ||
267 			(bus_space_read_4(nd->nd_bst, nd->nd_bsh, DD_SAVED_STOP) != dd_saved_stop)) {
268 		next_dma_print(nd);
269 		panic("DMA failure writing to continue regs");
270 	}
271 #endif
272 }
273 
274 void
275 next_dma_setup_curr_regs(nd)
276 	struct nextdma_config *nd;
277 {
278 	bus_addr_t dd_next;
279 	bus_addr_t dd_limit;
280 	bus_addr_t dd_saved_next;
281 	bus_addr_t dd_saved_limit;
282 
283 	DPRINTF(("DMA next_dma_setup_curr_regs()\n"));
284 
285 
286 	if (nd->_nd_map) {
287 		dd_next = nd->_nd_map->dm_segs[nd->_nd_idx].ds_addr;
288 		dd_limit = (nd->_nd_map->dm_segs[nd->_nd_idx].ds_addr +
289 				nd->_nd_map->dm_segs[nd->_nd_idx].ds_len);
290 		if (nd->nd_intr == NEXT_I_ENETX_DMA) {
291 			dd_limit |= 0x80000000; /* Ethernet transmit needs secret magic */
292 		}
293 	} else {
294 		dd_next = 0xdeadbeef;
295 		dd_limit = 0xdeadbeef;
296 	}
297 
298 	dd_saved_next = dd_next;
299 	dd_saved_limit = dd_limit;
300 
301 	if (nd->nd_intr == NEXT_I_ENETX_DMA) {
302 		bus_space_write_4(nd->nd_bst, nd->nd_bsh, DD_NEXT_INITBUF, dd_next);
303 	} else {
304 		bus_space_write_4(nd->nd_bst, nd->nd_bsh, DD_NEXT, dd_next);
305 	}
306 	bus_space_write_4(nd->nd_bst, nd->nd_bsh, DD_LIMIT, dd_limit);
307 	bus_space_write_4(nd->nd_bst, nd->nd_bsh, DD_SAVED_NEXT, dd_saved_next);
308 	bus_space_write_4(nd->nd_bst, nd->nd_bsh, DD_SAVED_LIMIT, dd_saved_limit);
309 
310 #ifdef DIAGNOSTIC
311 	if ((bus_space_read_4(nd->nd_bst, nd->nd_bsh, DD_NEXT_INITBUF) != dd_next) ||
312 			(bus_space_read_4(nd->nd_bst, nd->nd_bsh, DD_NEXT) != dd_next) ||
313 			(bus_space_read_4(nd->nd_bst, nd->nd_bsh, DD_LIMIT) != dd_limit) ||
314 			(bus_space_read_4(nd->nd_bst, nd->nd_bsh, DD_SAVED_NEXT) != dd_saved_next) ||
315 			(bus_space_read_4(nd->nd_bst, nd->nd_bsh, DD_SAVED_LIMIT) != dd_saved_limit)) {
316 		next_dma_print(nd);
317 		panic("DMA failure writing to current regs");
318 	}
319 #endif
320 }
321 
322 
323 /* This routine is used for debugging */
324 
325 void
326 next_dma_print(nd)
327 	struct nextdma_config *nd;
328 {
329 	u_long dd_csr;
330 	u_long dd_next;
331 	u_long dd_next_initbuf;
332 	u_long dd_limit;
333 	u_long dd_start;
334 	u_long dd_stop;
335 	u_long dd_saved_next;
336 	u_long dd_saved_limit;
337 	u_long dd_saved_start;
338 	u_long dd_saved_stop;
339 	char sbuf[256];
340 
341 	/* Read all of the registers before we print anything out,
342 	 * in case something changes
343 	 */
344 	dd_csr          = bus_space_read_4(nd->nd_bst, nd->nd_bsh, DD_CSR);
345 	dd_next         = bus_space_read_4(nd->nd_bst, nd->nd_bsh, DD_NEXT);
346 	dd_next_initbuf = bus_space_read_4(nd->nd_bst, nd->nd_bsh, DD_NEXT_INITBUF);
347 	dd_limit        = bus_space_read_4(nd->nd_bst, nd->nd_bsh, DD_LIMIT);
348 	dd_start        = bus_space_read_4(nd->nd_bst, nd->nd_bsh, DD_START);
349 	dd_stop         = bus_space_read_4(nd->nd_bst, nd->nd_bsh, DD_STOP);
350 	dd_saved_next   = bus_space_read_4(nd->nd_bst, nd->nd_bsh, DD_SAVED_NEXT);
351 	dd_saved_limit  = bus_space_read_4(nd->nd_bst, nd->nd_bsh, DD_SAVED_LIMIT);
352 	dd_saved_start  = bus_space_read_4(nd->nd_bst, nd->nd_bsh, DD_SAVED_START);
353 	dd_saved_stop   = bus_space_read_4(nd->nd_bst, nd->nd_bsh, DD_SAVED_STOP);
354 
355 	bitmask_snprintf((*(volatile u_long *)IIOV(NEXT_P_INTRSTAT)),
356 			 NEXT_INTR_BITS, sbuf, sizeof(sbuf));
357 	printf("NDMAP: *intrstat = 0x%s\n", sbuf);
358 
359 	bitmask_snprintf((*(volatile u_long *)IIOV(NEXT_P_INTRMASK)),
360 			 NEXT_INTR_BITS, sbuf, sizeof(sbuf));
361 	printf("NDMAP: *intrmask = 0x%s\n", sbuf);
362 
363 	/* NDMAP is Next DMA Print (really!) */
364 
365 	if (nd->_nd_map) {
366 		printf("NDMAP: nd->_nd_map->dm_mapsize = %d\n",
367 				nd->_nd_map->dm_mapsize);
368 		printf("NDMAP: nd->_nd_map->dm_nsegs = %d\n",
369 				nd->_nd_map->dm_nsegs);
370 		printf("NDMAP: nd->_nd_map->dm_segs[%d].ds_addr = 0x%08lx\n",
371 				nd->_nd_idx,nd->_nd_map->dm_segs[nd->_nd_idx].ds_addr);
372 		printf("NDMAP: nd->_nd_map->dm_segs[%d].ds_len = %d\n",
373 				nd->_nd_idx,nd->_nd_map->dm_segs[nd->_nd_idx].ds_len);
374 		printf("NDMAP: nd->_nd_map->dm_segs[%d].ds_xfer_len = %d\n",
375 				nd->_nd_idx,nd->_nd_map->dm_segs[nd->_nd_idx].ds_xfer_len);
376 	} else {
377 		printf("NDMAP: nd->_nd_map = NULL\n");
378 	}
379 	if (nd->_nd_map_cont) {
380 		printf("NDMAP: nd->_nd_map_cont->dm_mapsize = %d\n",
381 				nd->_nd_map_cont->dm_mapsize);
382 		printf("NDMAP: nd->_nd_map_cont->dm_nsegs = %d\n",
383 				nd->_nd_map_cont->dm_nsegs);
384 		printf("NDMAP: nd->_nd_map_cont->dm_segs[%d].ds_addr = 0x%08lx\n",
385 				nd->_nd_idx_cont,nd->_nd_map_cont->dm_segs[nd->_nd_idx_cont].ds_addr);
386 		printf("NDMAP: nd->_nd_map_cont->dm_segs[%d].ds_len = %d\n",
387 				nd->_nd_idx_cont,nd->_nd_map_cont->dm_segs[nd->_nd_idx_cont].ds_len);
388 		printf("NDMAP: nd->_nd_map_cont->dm_segs[%d].ds_xfer_len = %d\n",
389 				nd->_nd_idx_cont,nd->_nd_map_cont->dm_segs[nd->_nd_idx_cont].ds_xfer_len);
390 	} else {
391 		printf("NDMAP: nd->_nd_map_cont = NULL\n");
392 	}
393 
394 	bitmask_snprintf(dd_csr, DMACSR_BITS, sbuf, sizeof(sbuf));
395 	printf("NDMAP: dd->dd_csr          = 0x%s\n",   sbuf);
396 
397 	printf("NDMAP: dd->dd_saved_next   = 0x%08x\n", dd_saved_next);
398 	printf("NDMAP: dd->dd_saved_limit  = 0x%08x\n", dd_saved_limit);
399 	printf("NDMAP: dd->dd_saved_start  = 0x%08x\n", dd_saved_start);
400 	printf("NDMAP: dd->dd_saved_stop   = 0x%08x\n", dd_saved_stop);
401 	printf("NDMAP: dd->dd_next         = 0x%08x\n", dd_next);
402 	printf("NDMAP: dd->dd_next_initbuf = 0x%08x\n", dd_next_initbuf);
403 	printf("NDMAP: dd->dd_limit        = 0x%08x\n", dd_limit);
404 	printf("NDMAP: dd->dd_start        = 0x%08x\n", dd_start);
405 	printf("NDMAP: dd->dd_stop         = 0x%08x\n", dd_stop);
406 
407 	bitmask_snprintf(NEXT_I_BIT(nd->nd_intr), NEXT_INTR_BITS,
408 			 sbuf, sizeof(sbuf));
409 	printf("NDMAP: interrupt ipl (%ld) intr(0x%s)\n",
410 			NEXT_I_IPL(nd->nd_intr), sbuf);
411 }
412 
413 /****************************************************************/
414 
415 int
416 nextdma_intr(arg)
417      void *arg;
418 {
419   /* @@@ This is bogus, we can't be certain of arg's type
420 	 * unless the interrupt is for us.  For now we successfully
421 	 * cheat because DMA interrupts are the only things invoked
422 	 * at this interrupt level.
423 	 */
424   struct nextdma_config *nd = arg;
425 
426   if (!INTR_OCCURRED(nd->nd_intr)) return 0;
427   /* Handle dma interrupts */
428 
429 #ifdef ND_DEBUG
430 	if (nextdma_debug) {
431 		char sbuf[256];
432 
433 		bitmask_snprintf(NEXT_I_BIT(nd->nd_intr), NEXT_INTR_BITS,
434 				 sbuf, sizeof(sbuf));
435 		printf("DMA interrupt ipl (%ld) intr(0x%s)\n",
436 			NEXT_I_IPL(nd->nd_intr), sbuf);
437 	}
438 #endif
439 
440 #ifdef DIAGNOSTIC
441 	if (!nd->_nd_map) {
442 		next_dma_print(nd);
443 		panic("DMA missing current map in interrupt!\n");
444 	}
445 #endif
446 
447   {
448     int state = bus_space_read_4(nd->nd_bst, nd->nd_bsh, DD_CSR);
449 
450 		if (state & DMACSR_COMPLETE) {
451 			bus_addr_t onext;
452 			bus_addr_t olimit;
453 			bus_addr_t slimit;
454 
455 			DPRINTF(("DMA: finishing xfer\n"));
456 
457 			onext = nd->_nd_map->dm_segs[nd->_nd_idx].ds_addr;
458 			olimit = onext + nd->_nd_map->dm_segs[nd->_nd_idx].ds_len;
459 
460 			if (state & DMACSR_ENABLE) {
461 				if (state & DMACSR_SUPDATE) {
462 #ifdef DIAGNOSTIC
463 					printf("DMA: please send this output to port-next68k-maintainer@netbsd.org:\n");
464 					next_dma_print(nd);
465 					panic("DMA: condition not yet documented to occur\n");
466 #endif
467 					slimit = bus_space_read_4(nd->nd_bst, nd->nd_bsh, DD_LIMIT);
468 				} else {
469 					slimit = bus_space_read_4(nd->nd_bst, nd->nd_bsh, DD_SAVED_LIMIT);
470 				}
471 			} else {
472 				if (state & DMACSR_SUPDATE) {
473 					slimit = bus_space_read_4(nd->nd_bst, nd->nd_bsh, DD_NEXT);
474 				} else {
475 					slimit = bus_space_read_4(nd->nd_bst, nd->nd_bsh, DD_SAVED_LIMIT);
476 				}
477 			}
478 
479 			if (nd->nd_intr == NEXT_I_ENETX_DMA) {
480 				slimit &= ~0x80000000;
481 			}
482 
483 #ifdef DIAGNOSTIC
484 			if ((slimit < onext) || (slimit > olimit)) {
485 				next_dma_print(nd);
486 				panic("DMA: Unexpected limit registers in finish_xfer\n");
487 			}
488 #endif
489 
490 #if (defined(ND_DEBUG))
491 			if (nextdma_debug > 2) next_dma_print(nd);
492 #endif
493 
494 			nd->_nd_map->dm_segs[nd->_nd_idx].ds_xfer_len = slimit-onext;
495 
496 			/* If we've reached the end of the current map, then inform
497 			 * that we've completed that map.
498 			 */
499 			if (nd->_nd_map && ((nd->_nd_idx+1) == nd->_nd_map->dm_nsegs)) {
500 				if (nd->nd_completed_cb)
501 					(*nd->nd_completed_cb)(nd->_nd_map, nd->nd_cb_arg);
502 			}
503 			nd->_nd_map = 0;
504 			nd->_nd_idx = 0;
505 		}
506 #ifdef DIAGNOSTIC
507 		else if ((state & DMACSR_ENABLE) || (state & DMACSR_SUPDATE)) {
508 			next_dma_print(nd);
509 			panic("DMA Unexpected dma state in interrupt\n");
510 		}
511 #endif
512 
513 		if (state & DMACSR_ENABLE) {
514 
515 			next_dma_rotate(nd);
516 			next_dma_setup_cont_regs(nd);
517 
518 			{
519 				u_long dmadir;								/* 	DMACSR_SETREAD or DMACSR_SETWRITE */
520 
521 				if (state & DMACSR_READ) {
522 					dmadir = DMACSR_SETREAD;
523 				} else {
524 					dmadir = DMACSR_SETWRITE;
525 				}
526 
527 				if ((nd->_nd_map_cont == NULL) && (nd->_nd_idx+1 == nd->_nd_map->dm_nsegs)) {
528 					bus_space_write_4(nd->nd_bst, nd->nd_bsh, DD_CSR,
529 							DMACSR_CLRCOMPLETE | dmadir);
530 				} else {
531 					bus_space_write_4(nd->nd_bst, nd->nd_bsh, DD_CSR,
532 							DMACSR_CLRCOMPLETE | dmadir | DMACSR_SETSUPDATE);
533 				}
534 			}
535 
536 		} else {
537 
538 			/* Cleanup incomplete transfers */
539 			if (nd->_nd_map) {
540 				DPRINTF(("DMA: shutting down with non null map\n"));
541 				nd->_nd_map->dm_segs[nd->_nd_idx].ds_xfer_len = 0;
542 				if ((nd->_nd_idx+1) == nd->_nd_map->dm_nsegs) {
543 					if (nd->nd_completed_cb)
544 						(*nd->nd_completed_cb)(nd->_nd_map, nd->nd_cb_arg);
545 				}
546 				nd->_nd_map = 0;
547 				nd->_nd_idx = 0;
548 			}
549 
550 			/* Cleanup more incomplete transfers */
551 			if (nd->_nd_map_cont) {
552 				DPRINTF(("DMA: shutting down with non null continue map\n"));
553 
554 				while(nd->_nd_idx_cont < nd->_nd_map_cont->dm_nsegs) {
555 					nd->_nd_map_cont->dm_segs[nd->_nd_idx_cont].ds_xfer_len = 0;
556 					nd->_nd_idx_cont++;
557 				}
558 				if (nd->nd_completed_cb)
559 					(*nd->nd_completed_cb)(nd->_nd_map_cont, nd->nd_cb_arg);
560 
561 				nd->_nd_map_cont = 0;
562 				nd->_nd_idx_cont = 0;
563 			}
564 
565 			DPRINTF(("DMA: a shutdown occurred\n"));
566 
567 			bus_space_write_4(nd->nd_bst, nd->nd_bsh, DD_CSR, DMACSR_CLRCOMPLETE | DMACSR_RESET);
568 
569 			if (nd->nd_shutdown_cb) (*nd->nd_shutdown_cb)(nd->nd_cb_arg);
570 			return(1);
571 		}
572 	}
573 
574 #ifdef ND_DEBUG
575 	if (nextdma_debug) {
576 		char sbuf[256];
577 
578 		bitmask_snprintf(NEXT_I_BIT(nd->nd_intr), NEXT_INTR_BITS,
579 				 sbuf, sizeof(sbuf));
580 		printf("DMA exiting interrupt ipl (%ld) intr(0x%s)\n",
581 			NEXT_I_IPL(nd->nd_intr), sbuf);
582 	}
583 #endif
584 
585   return(1);
586 }
587 
588 /*
589  * Check to see if dma has finished for a channel */
590 int
591 nextdma_finished(nd)
592 	struct nextdma_config *nd;
593 {
594 	int r;
595 	int s;
596 	s = spldma();									/* @@@ should this be splimp()? */
597 	r = (nd->_nd_map == NULL) && (nd->_nd_map_cont == NULL);
598 	splx(s);
599 	return(r);
600 }
601 
602 void
603 nextdma_start(nd, dmadir)
604 	struct nextdma_config *nd;
605 	u_long dmadir;								/* 	DMACSR_SETREAD or DMACSR_SETWRITE */
606 {
607 
608 #ifdef DIAGNOSTIC
609 	if (!nextdma_finished(nd)) {
610 		char sbuf[256];
611 
612 		bitmask_snprintf(NEXT_I_BIT(nd->nd_intr), NEXT_INTR_BITS,
613 				 sbuf, sizeof(sbuf));
614 		panic("DMA trying to start before previous finished on intr(0x%s)\n", sbuf);
615 	}
616 #endif
617 
618 #ifdef ND_DEBUG
619 	if (nextdma_debug) {
620 		char sbuf[256];
621 
622 		bitmask_snprintf(NEXT_I_BIT(nd->nd_intr), NEXT_INTR_BITS,
623 				 sbuf, sizeof(sbuf));
624 		printf("DMA start (%ld) intr(0x%s)\n",
625 			NEXT_I_IPL(nd->nd_intr), sbuf);
626 	}
627 #endif
628 
629 #ifdef DIAGNOSTIC
630 	if (nd->_nd_map) {
631 		next_dma_print(nd);
632 		panic("DMA: nextdma_start() with non null map\n");
633 	}
634 	if (nd->_nd_map_cont) {
635 		next_dma_print(nd);
636 		panic("DMA: nextdma_start() with non null continue map\n");
637 	}
638 #endif
639 
640 #ifdef DIAGNOSTIC
641 	if ((dmadir != DMACSR_SETREAD) && (dmadir != DMACSR_SETWRITE)) {
642 		panic("DMA: nextdma_start(), dmadir arg must be DMACSR_SETREAD or DMACSR_SETWRITE\n");
643 	}
644 #endif
645 
646 	/* preload both the current and the continue maps */
647 	next_dma_rotate(nd);
648 
649 #ifdef DIAGNOSTIC
650 	if (!nd->_nd_map_cont) {
651 		panic("No map available in nextdma_start()");
652 	}
653 #endif
654 
655 	next_dma_rotate(nd);
656 
657 #ifdef ND_DEBUG
658 	if (nextdma_debug) {
659 		char sbuf[256];
660 
661 		bitmask_snprintf(NEXT_I_BIT(nd->nd_intr), NEXT_INTR_BITS,
662 				 sbuf, sizeof(sbuf));
663 		printf("DMA initiating DMA %s of %d segments on intr(0x%s)\n",
664 			(dmadir == DMACSR_SETREAD ? "read" : "write"), nd->_nd_map->dm_nsegs, sbuf);
665 	}
666 #endif
667 
668 	bus_space_write_4(nd->nd_bst, nd->nd_bsh, DD_CSR, 0);
669 	bus_space_write_4(nd->nd_bst, nd->nd_bsh, DD_CSR,
670 			DMACSR_INITBUF | DMACSR_RESET | dmadir);
671 
672 	next_dma_setup_curr_regs(nd);
673 	next_dma_setup_cont_regs(nd);
674 
675 #if (defined(ND_DEBUG))
676 	if (nextdma_debug > 2) next_dma_print(nd);
677 #endif
678 
679 	if ((nd->_nd_map_cont == NULL) && (nd->_nd_idx+1 == nd->_nd_map->dm_nsegs)) {
680 		bus_space_write_4(nd->nd_bst, nd->nd_bsh, DD_CSR,
681 				DMACSR_SETENABLE | dmadir);
682 	} else {
683 		bus_space_write_4(nd->nd_bst, nd->nd_bsh, DD_CSR,
684 				DMACSR_SETSUPDATE | DMACSR_SETENABLE | dmadir);
685 	}
686 }
687