xref: /netbsd-src/sys/arch/mipsco/obio/asc.c (revision e5fbc36ada28f9b9a5836ecffaf4a06aa1ebb687)
1 /*	$NetBSD: asc.c,v 1.24 2023/12/20 15:29:05 thorpej Exp $	*/
2 /*-
3  * Copyright (c) 2000 The NetBSD Foundation, Inc.
4  * All rights reserved.
5  *
6  * This code is derived from software contributed to The NetBSD Foundation
7  * by Wayne Knowles
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in the
16  *    documentation and/or other materials provided with the distribution.
17  *
18  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
19  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
20  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
21  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
22  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
23  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
24  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
25  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
26  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
27  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
28  * POSSIBILITY OF SUCH DAMAGE.
29  */
30 
31 #include <sys/cdefs.h>
32 __KERNEL_RCSID(0, "$NetBSD: asc.c,v 1.24 2023/12/20 15:29:05 thorpej Exp $");
33 
34 #include <sys/types.h>
35 #include <sys/param.h>
36 #include <sys/systm.h>
37 #include <sys/kernel.h>
38 #include <sys/errno.h>
39 #include <sys/device.h>
40 #include <sys/buf.h>
41 
42 #include <uvm/uvm_extern.h>
43 
44 #include <dev/scsipi/scsi_all.h>
45 #include <dev/scsipi/scsipi_all.h>
46 #include <dev/scsipi/scsiconf.h>
47 #include <dev/scsipi/scsi_message.h>
48 
49 #include <machine/cpu.h>
50 #include <machine/autoconf.h>
51 #include <machine/mainboard.h>
52 #include <machine/bus.h>
53 
54 #include <mipsco/obio/rambo.h>
55 
56 #include <dev/ic/ncr53c9xreg.h>
57 #include <dev/ic/ncr53c9xvar.h>
58 
59 struct asc_softc {
60 	struct ncr53c9x_softc	sc_ncr53c9x;	/* glue to MI code */
61         struct evcnt		sc_intrcnt; 	/* Interrupt counter */
62 	bus_space_tag_t		sc_bst;
63 	bus_space_handle_t	sc_bsh;		/* NCR 53c94 registers */
64 	bus_space_handle_t	dm_bsh;		/* RAMBO registers */
65 	bus_dma_tag_t		sc_dmat;
66         bus_dmamap_t		sc_dmamap;
67         uint8_t			**sc_dmaaddr;
68 	size_t			*sc_dmalen;
69 	size_t			sc_dmasize;
70 	int			sc_flags;
71 #define DMA_IDLE	0x0
72 #define	DMA_PULLUP	0x1
73 #define	DMA_ACTIVE	0x2
74 #define	DMA_MAPLOADED	0x4
75         uint32_t		dm_mode;
76         int			dm_curseg;
77 };
78 
79 static int	ascmatch(device_t, cfdata_t, void *);
80 static void	ascattach(device_t, device_t, void *);
81 
82 CFATTACH_DECL_NEW(asc, sizeof(struct asc_softc),
83     ascmatch, ascattach, NULL, NULL);
84 
85 /*
86  * Functions and the switch for the MI code.
87  */
88 static uint8_t	asc_read_reg(struct ncr53c9x_softc *, int);
89 static void	asc_write_reg(struct ncr53c9x_softc *, int, uint8_t);
90 static int	asc_dma_isintr(struct ncr53c9x_softc *);
91 static void	asc_dma_reset(struct ncr53c9x_softc *);
92 static int	asc_dma_intr(struct ncr53c9x_softc *);
93 static int	asc_dma_setup(struct ncr53c9x_softc *, uint8_t **,
94 				    size_t *, int, size_t *);
95 static void	asc_dma_go(struct ncr53c9x_softc *);
96 static void	asc_dma_stop(struct ncr53c9x_softc *);
97 static int	asc_dma_isactive(struct ncr53c9x_softc *);
98 
99 static struct ncr53c9x_glue asc_glue = {
100 	asc_read_reg,
101 	asc_write_reg,
102 	asc_dma_isintr,
103 	asc_dma_reset,
104 	asc_dma_intr,
105 	asc_dma_setup,
106 	asc_dma_go,
107 	asc_dma_stop,
108 	asc_dma_isactive,
109 	NULL,			/* gl_clear_latched_intr */
110 };
111 
112 static int	asc_intr(void *);
113 
114 #define MAX_SCSI_XFER   (64 * 1024)
115 #define	MAX_DMA_SZ	MAX_SCSI_XFER
116 #define	DMA_SEGS	(MAX_DMA_SZ / PAGE_SIZE)
117 
118 static int
ascmatch(device_t parent,cfdata_t cf,void * aux)119 ascmatch(device_t parent, cfdata_t cf, void *aux)
120 {
121 
122 	return 1;
123 }
124 
125 static void
ascattach(device_t parent,device_t self,void * aux)126 ascattach(device_t parent, device_t self, void *aux)
127 {
128 	struct asc_softc *esc = device_private(self);
129 	struct ncr53c9x_softc *sc = &esc->sc_ncr53c9x;
130 	struct confargs *ca = aux;
131 
132 	/*
133 	 * Set up glue for MI code early; we use some of it here.
134 	 */
135 	sc->sc_dev = self;
136 	sc->sc_glue = &asc_glue;
137 
138 	esc->sc_bst = ca->ca_bustag;
139 	esc->sc_dmat = ca->ca_dmatag;
140 
141 	if (bus_space_map(ca->ca_bustag, ca->ca_addr,
142 	    16 * 4, /* sizeof (ncr53c9xreg) */
143 	    BUS_SPACE_MAP_LINEAR,
144 	    &esc->sc_bsh) != 0) {
145 		aprint_error(": cannot map registers\n");
146 		return;
147 	}
148 
149 	if (bus_space_map(ca->ca_bustag, RAMBO_BASE, sizeof(struct rambo_ch),
150 	    BUS_SPACE_MAP_LINEAR, &esc->dm_bsh) != 0) {
151 		aprint_error(": cannot map DMA registers\n");
152 		return;
153 	}
154 
155         if (bus_dmamap_create(esc->sc_dmat, MAX_DMA_SZ,
156 	    DMA_SEGS, MAX_DMA_SZ, RB_BOUNDRY, BUS_DMA_WAITOK,
157 	    &esc->sc_dmamap) != 0) {
158 		aprint_error(": failed to create dmamap\n");
159 		return;
160         }
161 
162 	evcnt_attach_dynamic(&esc->sc_intrcnt, EVCNT_TYPE_INTR, NULL,
163 	    device_xname(self), "intr");
164 
165 	esc->sc_flags = DMA_IDLE;
166 	asc_dma_reset(sc);
167 
168 	/* Other settings */
169 	sc->sc_id = 7;
170 	sc->sc_freq = 24;	/* 24 MHz clock */
171 
172 	/*
173 	 * Setup for genuine NCR 53C94 SCSI Controller
174 	 */
175 
176 	sc->sc_cfg1 = sc->sc_id | NCRCFG1_PARENB;
177 	sc->sc_cfg2 = NCRCFG2_SCSI2 | NCRCFG2_FE;
178 	sc->sc_cfg3 = NCRCFG3_CDB | NCRCFG3_QTE | NCRCFG3_FSCSI;
179 	sc->sc_rev = NCR_VARIANT_NCR53C94;
180 
181 	sc->sc_minsync = (1000 / sc->sc_freq) * 5 / 4;
182 	sc->sc_maxxfer = MAX_SCSI_XFER;
183 
184 #ifdef OLDNCR
185 	if (NCR_READ_REG(sc, NCR_CFG3) == 0) {
186 		aprint_normal(" [old revision]");
187 		sc->sc_cfg2 = 0;
188 		sc->sc_cfg3 = 0;
189 		sc->sc_minsync = 0;
190 	}
191 #endif
192 
193 	sc->sc_adapter.adapt_minphys = minphys;
194 	sc->sc_adapter.adapt_request = ncr53c9x_scsipi_request;
195 	ncr53c9x_attach(sc);
196 
197 	bus_intr_establish(esc->sc_bst, SYS_INTR_SCSI, 0, 0, asc_intr, esc);
198 }
199 
200 /*
201  * Glue functions.
202  */
203 
204 static uint8_t
asc_read_reg(struct ncr53c9x_softc * sc,int reg)205 asc_read_reg(struct ncr53c9x_softc *sc, int reg)
206 {
207 	struct asc_softc *esc = (struct asc_softc *)sc;
208 
209 	return bus_space_read_1(esc->sc_bst, esc->sc_bsh, reg * 4 + 3);
210 }
211 
212 static void
asc_write_reg(struct ncr53c9x_softc * sc,int reg,uint8_t val)213 asc_write_reg(struct ncr53c9x_softc *sc, int reg, uint8_t val)
214 {
215 	struct asc_softc *esc = (struct asc_softc *)sc;
216 
217 	bus_space_write_1(esc->sc_bst, esc->sc_bsh, reg * 4 + 3, val);
218 }
219 
220 static void
dma_status(struct ncr53c9x_softc * sc)221 dma_status(struct ncr53c9x_softc *sc)
222 {
223 	struct asc_softc *esc = (struct asc_softc *)sc;
224 	int    count;
225 	int    stat;
226 	void   *addr;
227 	uint32_t  tc;
228 
229 	tc = (asc_read_reg(sc, NCR_TCM) << 8) + asc_read_reg(sc, NCR_TCL);
230 	count = bus_space_read_2(esc->sc_bst, esc->dm_bsh, RAMBO_BLKCNT);
231 	stat  = bus_space_read_4(esc->sc_bst, esc->dm_bsh, RAMBO_MODE);
232 	addr  = (void *)bus_space_read_4(esc->sc_bst, esc->dm_bsh, RAMBO_CADDR);
233 
234 	printf("rambo status: cnt=%x addr=%p stat=%08x tc=%04x "
235 	    "ncr_stat=0x%02x ncr_fifo=0x%02x\n",
236 	    count, addr, stat, tc,
237 	    asc_read_reg(sc, NCR_STAT),
238 	    asc_read_reg(sc, NCR_FFLAG));
239 }
240 
241 static inline void
check_fifo(struct asc_softc * esc)242 check_fifo(struct asc_softc *esc)
243 {
244 	int i = 100;
245 
246 	while (i && !(bus_space_read_4(esc->sc_bst, esc->dm_bsh,
247 	    RAMBO_MODE) & RB_FIFO_EMPTY)) {
248 		 DELAY(1);
249 		i--;
250 	}
251 
252 	if (i == 0) {
253 		dma_status((void *)esc);
254 		panic("fifo didn't flush");
255 	}
256 }
257 
258 static int
asc_dma_isintr(struct ncr53c9x_softc * sc)259 asc_dma_isintr(struct ncr53c9x_softc *sc)
260 {
261 
262 	return NCR_READ_REG(sc, NCR_STAT) & NCRSTAT_INT;
263 }
264 
265 static void
asc_dma_reset(struct ncr53c9x_softc * sc)266 asc_dma_reset(struct ncr53c9x_softc *sc)
267 {
268 	struct asc_softc *esc = (struct asc_softc *)sc;
269 
270  	bus_space_write_2(esc->sc_bst, esc->dm_bsh, RAMBO_BLKCNT, 0);
271 	bus_space_write_4(esc->sc_bst, esc->dm_bsh, RAMBO_MODE,
272 	    RB_CLRFIFO|RB_CLRERROR);
273 	DELAY(10);
274  	bus_space_write_4(esc->sc_bst, esc->dm_bsh, RAMBO_MODE, 0);
275 
276 	if (esc->sc_flags & DMA_MAPLOADED)
277 		bus_dmamap_unload(esc->sc_dmat, esc->sc_dmamap);
278 
279 	esc->sc_flags = DMA_IDLE;
280 }
281 
282 /*
283  * Setup a DMA transfer
284  */
285 
286 static int
asc_dma_setup(struct ncr53c9x_softc * sc,uint8_t ** addr,size_t * len,int datain,size_t * dmasize)287 asc_dma_setup(struct ncr53c9x_softc *sc, uint8_t **addr, size_t *len,
288     int datain, size_t *dmasize)
289 {
290 	struct asc_softc *esc = (struct asc_softc *)sc;
291 	paddr_t paddr;
292         size_t count, blocks;
293 	int prime, err;
294 
295 #ifdef DIAGNOSTIC
296 	if (esc->sc_flags & DMA_ACTIVE) {
297 		dma_status(sc);
298 		panic("DMA active");
299 	}
300 #endif
301 
302 	esc->sc_dmaaddr = addr;
303 	esc->sc_dmalen  = len;
304 	esc->sc_dmasize = *dmasize;
305 	esc->sc_flags   = datain ? DMA_PULLUP : 0;
306 
307 	NCR_DMA(("asc_dma_setup va=%p len=%d datain=%d count=%d\n",
308 	    *addr, *len, datain, esc->sc_dmasize));
309 
310 	if (esc->sc_dmasize == 0)
311 		return 0;
312 
313 	/* have dmamap for the transferring addresses */
314 	if ((err = bus_dmamap_load(esc->sc_dmat, esc->sc_dmamap,
315 	    *esc->sc_dmaaddr, esc->sc_dmasize, NULL /* kernel address */,		    BUS_DMA_NOWAIT)) != 0)
316 		panic("%s: bus_dmamap_load err=%d",
317 		    device_xname(sc->sc_dev), err);
318 
319 	esc->sc_flags |= DMA_MAPLOADED;
320 
321 	paddr  = esc->sc_dmamap->dm_segs[0].ds_addr;
322 	count  = esc->sc_dmamap->dm_segs[0].ds_len;
323 	prime  = (uint32_t)paddr & 0x3f;
324 	blocks = (prime + count + 63) >> 6;
325 
326 	esc->dm_mode = datain ? RB_DMA_WR : RB_DMA_RD;
327 
328 	/* Set transfer direction and disable DMA */
329  	bus_space_write_4(esc->sc_bst, esc->dm_bsh, RAMBO_MODE, esc->dm_mode);
330 
331 	/* Load DMA transfer address */
332  	bus_space_write_4(esc->sc_bst, esc->dm_bsh, RAMBO_LADDR, paddr & ~0x3f);
333 
334 	/* Load number of blocks to DMA (1 block = 64 bytes) */
335  	bus_space_write_2(esc->sc_bst, esc->dm_bsh, RAMBO_BLKCNT, blocks);
336 
337 	/* If non block-aligned transfer prime FIFO manually */
338 	if (prime) {
339 		/* Enable DMA to prime the FIFO buffer */
340 		bus_space_write_4(esc->sc_bst, esc->dm_bsh,
341 		    RAMBO_MODE, esc->dm_mode | RB_DMA_ENABLE);
342 
343 		if (esc->sc_flags & DMA_PULLUP) {
344 			/* Read from NCR 53c94 controller*/
345 			uint16_t *p;
346 
347 			p = (uint16_t *)((uint32_t)*esc->sc_dmaaddr & ~0x3f);
348 			bus_space_write_multi_2(esc->sc_bst, esc->dm_bsh,
349 			    RAMBO_FIFO, p, prime>>1);
350 		} else
351 			/* Write to NCR 53C94 controller */
352 			while (prime > 0) {
353 				(void)bus_space_read_2(esc->sc_bst, esc->dm_bsh,
354 				    RAMBO_FIFO);
355 				prime -= 2;
356 			}
357 		/* Leave DMA disabled while we setup NCR controller */
358 		bus_space_write_4(esc->sc_bst, esc->dm_bsh, RAMBO_MODE,
359 		    esc->dm_mode);
360 	}
361 
362 	bus_dmamap_sync(esc->sc_dmat, esc->sc_dmamap, 0, esc->sc_dmasize,
363 	    datain ? BUS_DMASYNC_PREREAD : BUS_DMASYNC_PREWRITE);
364 
365 	esc->dm_curseg = 0;
366 	esc->dm_mode |= RB_DMA_ENABLE;
367 	if (esc->sc_dmamap->dm_nsegs > 1)
368 		esc->dm_mode |= RB_INT_ENABLE;	/* Requires DMA chaining */
369 
370 	return 0;
371 }
372 
373 static void
asc_dma_go(struct ncr53c9x_softc * sc)374 asc_dma_go(struct ncr53c9x_softc *sc)
375 {
376 	struct asc_softc *esc = (struct asc_softc *)sc;
377 
378 	/* Start DMA */
379 	bus_space_write_4(esc->sc_bst, esc->dm_bsh, RAMBO_MODE, esc->dm_mode);
380 
381 	esc->sc_flags |= DMA_ACTIVE;
382 }
383 
384 static int
asc_dma_intr(struct ncr53c9x_softc * sc)385 asc_dma_intr(struct ncr53c9x_softc *sc)
386 {
387 	struct asc_softc *esc = (struct asc_softc *)sc;
388 
389 	size_t      resid, len;
390 	int         trans;
391 	uint32_t    status;
392 	u_int tcl, tcm;
393 
394 #ifdef DIAGNOSTIC
395 	if ((esc->sc_flags & DMA_ACTIVE) == 0) {
396 		dma_status(sc);
397 		panic("DMA not active");
398 	}
399 #endif
400 
401 	resid = 0;
402 	if ((esc->sc_flags & DMA_PULLUP) == 0 &&
403 	    (resid = (NCR_READ_REG(sc, NCR_FFLAG) & NCRFIFO_FF)) != 0) {
404 		NCR_DMA(("asc_intr: empty FIFO of %d ", resid));
405 		DELAY(10);
406 	}
407 
408 	resid += (tcl = NCR_READ_REG(sc, NCR_TCL)) +
409 	    ((tcm = NCR_READ_REG(sc, NCR_TCM)) << 8);
410 
411 	if (esc->sc_dmasize == 0) { /* Transfer pad operation */
412 		NCR_DMA(("asc_intr: discard %d bytes\n", resid));
413 		return 0;
414 	}
415 
416 	trans = esc->sc_dmasize - resid;
417 	if (trans < 0) {			/* transferred < 0 ? */
418 		printf("%s: xfer (%d) > req (%d)\n",
419 		    __func__, trans, esc->sc_dmasize);
420 		trans = esc->sc_dmasize;
421 	}
422 
423 	NCR_DMA(("asc_intr: tcl=%d, tcm=%d; trans=%d, resid=%d\n",
424 	    tcl, tcm, trans, resid));
425 
426 	status = bus_space_read_4(esc->sc_bst, esc->dm_bsh, RAMBO_MODE);
427 
428 	if ((status & RB_FIFO_EMPTY) == 0) { /* Data left in RAMBO FIFO */
429 		if ((esc->sc_flags & DMA_PULLUP) != 0) { /* SCSI Read */
430 			paddr_t ptr;
431 			uint16_t *p;
432 
433 			resid  = status & 0x1f;
434 
435 			/* take the address of block to fixed up */
436 			ptr = bus_space_read_4(esc->sc_bst, esc->dm_bsh,
437 			    RAMBO_CADDR);
438 			/* find the starting address of fractional data */
439 			p = (uint16_t *)MIPS_PHYS_TO_KSEG0(ptr + (resid << 1));
440 
441 			/* duplicate trailing data to FIFO for force flush */
442 			len = RB_BLK_CNT - resid;
443 			bus_space_write_multi_2(esc->sc_bst, esc->dm_bsh,
444 			    RAMBO_FIFO, p, len);
445 			check_fifo(esc);
446 		} else {		/* SCSI Write */
447 			bus_space_write_4(esc->sc_bst, esc->dm_bsh,
448 			    RAMBO_MODE, 0);
449 			bus_space_write_4(esc->sc_bst, esc->dm_bsh,
450 			    RAMBO_MODE, RB_CLRFIFO);
451 		}
452 	}
453 
454  	bus_space_write_2(esc->sc_bst, esc->dm_bsh, RAMBO_BLKCNT, 0);
455 
456 	bus_space_write_4(esc->sc_bst, esc->dm_bsh, RAMBO_MODE, 0);
457 
458 	bus_dmamap_sync(esc->sc_dmat, esc->sc_dmamap,
459 	    0, esc->sc_dmasize,
460 	    (esc->sc_flags & DMA_PULLUP) != 0 ?
461 	    BUS_DMASYNC_POSTREAD : BUS_DMASYNC_POSTWRITE);
462 	bus_dmamap_unload(esc->sc_dmat, esc->sc_dmamap);
463 
464 	*esc->sc_dmaaddr += trans;
465 	*esc->sc_dmalen  -= trans;
466 
467 	esc->sc_flags = DMA_IDLE;
468 
469 	return 0;
470 }
471 
472 
473 static void
asc_dma_stop(struct ncr53c9x_softc * sc)474 asc_dma_stop(struct ncr53c9x_softc *sc)
475 {
476 	struct asc_softc *esc = (struct asc_softc *)sc;
477 
478 	bus_space_write_4(esc->sc_bst, esc->dm_bsh, RAMBO_MODE, 0);
479 	if ((esc->sc_flags & DMA_MAPLOADED) != 0)
480 		bus_dmamap_unload(esc->sc_dmat, esc->sc_dmamap);
481 	esc->sc_flags = DMA_IDLE;
482 }
483 
484 static int
asc_dma_isactive(struct ncr53c9x_softc * sc)485 asc_dma_isactive(struct ncr53c9x_softc *sc)
486 {
487 	struct asc_softc *esc = (struct asc_softc *)sc;
488 	return (esc->sc_flags & DMA_ACTIVE) != 0 ? 1 : 0;
489 }
490 
491 static void
rambo_dma_chain(struct asc_softc * esc)492 rambo_dma_chain(struct asc_softc *esc)
493 {
494 	int seg;
495 	size_t	count, blocks;
496 	paddr_t paddr;
497 
498 	seg = ++esc->dm_curseg;
499 
500 #ifdef DIAGNOSTIC
501 	if ((esc->sc_flags & DMA_ACTIVE) == 0 || seg > esc->sc_dmamap->dm_nsegs)
502 		panic("Unexpected DMA chaining intr");
503 
504 	/* Interrupt can only occur at terminal count, but double check */
505 	if (bus_space_read_2(esc->sc_bst, esc->dm_bsh, RAMBO_BLKCNT)) {
506 		dma_status((void *)esc);
507 		panic("rambo blkcnt != 0");
508 	}
509 #endif
510 
511 	paddr  = esc->sc_dmamap->dm_segs[seg].ds_addr;
512 	count  = esc->sc_dmamap->dm_segs[seg].ds_len;
513 	blocks = (count + 63) >> 6;
514 
515 	/* Disable DMA interrupt if last segment */
516 	if (seg + 1 > esc->sc_dmamap->dm_nsegs) {
517 		bus_space_write_4(esc->sc_bst, esc->dm_bsh,
518 		    RAMBO_MODE, esc->dm_mode & ~RB_INT_ENABLE);
519 	}
520 
521 	/* Load transfer address for next DMA chain */
522  	bus_space_write_4(esc->sc_bst, esc->dm_bsh, RAMBO_LADDR, paddr);
523 
524 	/* DMA restarts when we enter a new block count */
525  	bus_space_write_2(esc->sc_bst, esc->dm_bsh, RAMBO_BLKCNT, blocks);
526 }
527 
528 static int
asc_intr(void * arg)529 asc_intr(void *arg)
530 {
531 	uint32_t dma_stat;
532 	struct asc_softc *esc = arg;
533 	struct ncr53c9x_softc *sc = &esc->sc_ncr53c9x;
534 
535 	esc->sc_intrcnt.ev_count++;
536 
537 	/* Check for RAMBO DMA Interrupt */
538 	dma_stat = bus_space_read_4(esc->sc_bst, esc->dm_bsh, RAMBO_MODE);
539 	if ((dma_stat & RB_INTR_PEND) != 0) {
540 		rambo_dma_chain(esc);
541 	}
542 	/* Check for NCR 53c94 interrupt */
543 	if (NCR_READ_REG(sc, NCR_STAT) & NCRSTAT_INT) {
544 		ncr53c9x_intr(sc);
545 	}
546 	return 0;
547 }
548