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vidcaudio.c revision 1.12
      1 /*	$NetBSD: vidcaudio.c,v 1.12 2002/10/01 03:10:17 thorpej Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1995 Melvin Tang-Richardson
      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 the RiscBSD team.
     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 /*
     33  * audio driver for the RiscPC 16 bit sound
     34  *
     35  * Interfaces with the NetBSD generic audio driver to provide SUN
     36  * /dev/audio (partial) compatibility.
     37  */
     38 
     39 #include <sys/param.h>	/* proc.h */
     40 
     41 __KERNEL_RCSID(0, "$NetBSD: vidcaudio.c,v 1.12 2002/10/01 03:10:17 thorpej Exp $");
     42 
     43 #include <sys/conf.h>   /* autoconfig functions */
     44 #include <sys/device.h> /* device calls */
     45 #include <sys/proc.h>	/* device calls */
     46 #include <sys/audioio.h>
     47 #include <sys/errno.h>
     48 #include <sys/systm.h>
     49 
     50 #include <uvm/uvm_extern.h>
     51 
     52 #include <dev/audio_if.h>
     53 
     54 #include <machine/intr.h>
     55 #include <arm/arm32/katelib.h>
     56 
     57 #include <arm/iomd/vidcaudiovar.h>
     58 #include <arm/iomd/iomdreg.h>
     59 #include <arm/iomd/iomdvar.h>
     60 #include <arm/iomd/vidc.h>
     61 #include <arm/mainbus/mainbus.h>
     62 #include <arm/iomd/waveform.h>
     63 #include "vidcaudio.h"
     64 
     65 extern int *vidc_base;
     66 
     67 #undef DEBUG
     68 
     69 struct audio_general {
     70 	vaddr_t silence;
     71 	irqhandler_t ih;
     72 
     73 	void (*intr) (void *);
     74 	void *arg;
     75 
     76 	paddr_t next_cur;
     77 	paddr_t next_end;
     78 	void (*next_intr) (void *);
     79 	void *next_arg;
     80 
     81 	int buffer;
     82 	int in_progress;
     83 
     84 	int open;
     85 } ag;
     86 
     87 struct vidcaudio_softc {
     88 	struct device device;
     89 
     90 	int open;
     91 };
     92 
     93 int  vidcaudio_probe	__P((struct device *parent, struct cfdata *cf, void *aux));
     94 void vidcaudio_attach	__P((struct device *parent, struct device *self, void *aux));
     95 int  vidcaudio_open	__P((void *addr, int flags));
     96 void vidcaudio_close	__P((void *addr));
     97 
     98 int vidcaudio_intr	__P((void *arg));
     99 int vidcaudio_dma_program	__P((vaddr_t cur, vaddr_t end, void (*intr)(void *), void *arg));
    100 void vidcaudio_dummy_routine	__P((void *arg));
    101 int vidcaudio_stereo	__P((int channel, int position));
    102 int vidcaudio_rate	__P((int rate));
    103 void vidcaudio_shutdown	__P((void));
    104 
    105 static int sound_dma_intr;
    106 
    107 CFATTACH_DECL(vidcaudio, sizeof(struct vidcaudio_softc),
    108     vidcaudio_probe, vidcaudio_attach, NULL, NULL)
    109 
    110 int    vidcaudio_query_encoding  __P((void *, struct audio_encoding *));
    111 int    vidcaudio_set_params	 __P((void *, int, int, struct audio_params *, struct audio_params *));
    112 int    vidcaudio_round_blocksize __P((void *, int));
    113 int    vidcaudio_start_output	 __P((void *, void *, int, void (*)(void *),
    114 					 void *));
    115 int    vidcaudio_start_input	 __P((void *, void *, int, void (*)(void *),
    116 					 void *));
    117 int    vidcaudio_halt_output	 __P((void *));
    118 int    vidcaudio_halt_input 	 __P((void *));
    119 int    vidcaudio_speaker_ctl	 __P((void *, int));
    120 int    vidcaudio_getdev		 __P((void *, struct audio_device *));
    121 int    vidcaudio_set_port	 __P((void *, mixer_ctrl_t *));
    122 int    vidcaudio_get_port	 __P((void *, mixer_ctrl_t *));
    123 int    vidcaudio_query_devinfo	 __P((void *, mixer_devinfo_t *));
    124 int    vidcaudio_get_props	 __P((void *));
    125 
    126 struct audio_device vidcaudio_device = {
    127 	"VidcAudio 8-bit",
    128 	"x",
    129 	"vidcaudio"
    130 };
    131 
    132 struct audio_hw_if vidcaudio_hw_if = {
    133 	vidcaudio_open,
    134 	vidcaudio_close,
    135 	0,
    136 	vidcaudio_query_encoding,
    137 	vidcaudio_set_params,
    138 	vidcaudio_round_blocksize,
    139 	0,
    140 	0,
    141 	0,
    142 	vidcaudio_start_output,
    143 	vidcaudio_start_input,
    144 	vidcaudio_halt_output,
    145 	vidcaudio_halt_input,
    146 	vidcaudio_speaker_ctl,
    147 	vidcaudio_getdev,
    148 	0,
    149 	vidcaudio_set_port,
    150 	vidcaudio_get_port,
    151 	vidcaudio_query_devinfo,
    152 	0,
    153 	0,
    154 	0,
    155 	0,
    156 	vidcaudio_get_props,
    157 	0,
    158 	0,
    159 	0,
    160 };
    161 
    162 
    163 void
    164 vidcaudio_beep_generate()
    165 {
    166 	vidcaudio_dma_program(ag.silence, ag.silence+sizeof(beep_waveform)-16,
    167 	    vidcaudio_dummy_routine, NULL);
    168 }
    169 
    170 
    171 int
    172 vidcaudio_probe(parent, cf, aux)
    173 	struct device *parent;
    174 	struct cfdata* cf;
    175 	void *aux;
    176 {
    177 	int id;
    178 
    179 	id = IOMD_ID;
    180 
    181 	/* So far I only know about this IOMD */
    182 	switch (id) {
    183 	case RPC600_IOMD_ID:
    184 		return(1);
    185 		break;
    186 	case ARM7500_IOC_ID:
    187 	case ARM7500FE_IOC_ID:
    188 		return(1);
    189 		break;
    190 	default:
    191 		printf("vidcaudio: Unknown IOMD id=%04x", id);
    192 		break;
    193 	}
    194 
    195 	return (0);
    196 }
    197 
    198 
    199 void
    200 vidcaudio_attach(parent, self, aux)
    201 	struct device *parent;
    202 	struct device *self;
    203 	void *aux;
    204 {
    205 	struct vidcaudio_softc *sc = (void *)self;
    206 	int id;
    207 
    208 	sc->open = 0;
    209 	ag.in_progress = 0;
    210 
    211 	ag.next_cur = 0;
    212 	ag.next_end = 0;
    213 	ag.next_intr = NULL;
    214 	ag.next_arg = NULL;
    215 
    216 	vidcaudio_rate(32); /* 24*1024*/
    217 
    218 	/* Program the silence buffer and reset the DMA channel */
    219 	ag.silence = uvm_km_alloc(kernel_map, NBPG);
    220 	if (ag.silence == NULL)
    221 		panic("vidcaudio: Cannot allocate memory");
    222 
    223 	memset((char *)ag.silence, 0, NBPG);
    224 	memcpy((char *)ag.silence, (char *)beep_waveform, sizeof(beep_waveform));
    225 
    226 	ag.buffer = 0;
    227 
    228 	/* Install the irq handler for the DMA interrupt */
    229 	ag.ih.ih_func = vidcaudio_intr;
    230 	ag.ih.ih_arg = NULL;
    231 	ag.ih.ih_level = IPL_AUDIO;
    232 	ag.ih.ih_name = "vidcaudio";
    233 
    234 	ag.intr = NULL;
    235 /*	ag.nextintr = NULL;*/
    236 
    237 	id = IOMD_ID;
    238 
    239 	switch (id) {
    240 	case RPC600_IOMD_ID:
    241 		sound_dma_intr = IRQ_DMASCH0;
    242 		break;
    243 	case ARM7500_IOC_ID:
    244 	case ARM7500FE_IOC_ID:
    245 		sound_dma_intr = IRQ_SDMA;
    246 		break;
    247 	}
    248 
    249 	disable_irq(sound_dma_intr);
    250 
    251 	if (irq_claim(sound_dma_intr, &(ag.ih)))
    252 		panic("vidcaudio: couldn't claim IRQ %d", sound_dma_intr);
    253 
    254 	disable_irq(sound_dma_intr);
    255 
    256 	printf("\n");
    257 
    258 	vidcaudio_dma_program(ag.silence, ag.silence+NBPG-16,
    259 	    vidcaudio_dummy_routine, NULL);
    260 
    261 	audio_attach_mi(&vidcaudio_hw_if, sc, &sc->device);
    262 
    263 #ifdef DEBUG
    264 	printf(" UNDER DEVELOPMENT (nuts)\n");
    265 #endif
    266 }
    267 
    268 int
    269 vidcaudio_open(addr, flags)
    270 	void *addr;
    271 	int flags;
    272 {
    273 	struct vidcaudio_softc *sc = addr;
    274 
    275 #ifdef DEBUG
    276 	printf("DEBUG: vidcaudio_open called\n");
    277 #endif
    278 
    279 	if (sc->open)
    280 		return EBUSY;
    281 
    282 	sc->open = 1;
    283 	ag.open = 1;
    284 
    285 	return 0;
    286 }
    287 
    288 void
    289 vidcaudio_close(addr)
    290 	void *addr;
    291 {
    292 	struct vidcaudio_softc *sc = addr;
    293 
    294 	vidcaudio_shutdown();
    295 
    296 #ifdef DEBUG
    297 	printf("DEBUG: vidcaudio_close called\n");
    298 #endif
    299 
    300 	sc->open = 0;
    301 	ag.open = 0;
    302 }
    303 
    304 /* ************************************************************************* *
    305  | Interface to the generic audio driver                                     |
    306  * ************************************************************************* */
    307 
    308 int
    309 vidcaudio_query_encoding(addr, fp)
    310 	void *addr;
    311 	struct audio_encoding *fp;
    312 {
    313 	switch (fp->index) {
    314 	case 0:
    315 		strcpy(fp->name, "vidc");
    316 		fp->encoding = AUDIO_ENCODING_ULAW;
    317 		fp->precision = 8;
    318 		fp->flags = 0;
    319 		break;
    320 
    321 	default:
    322 		return(EINVAL);
    323 	}
    324 	return 0;
    325 }
    326 
    327 int
    328 vidcaudio_set_params(addr, setmode, usemode, p, r)
    329 	void *addr;
    330 	int setmode, usemode;
    331 	struct audio_params *p, *r;
    332 {
    333 	if (p->encoding != AUDIO_ENCODING_ULAW ||
    334 	    p->channels != 8)
    335 		return EINVAL;
    336 	vidcaudio_rate(4 * p->sample_rate / (3 * 1024)); /* XXX probably wrong */
    337 
    338 	return 0;
    339 }
    340 
    341 int
    342 vidcaudio_round_blocksize(addr, blk)
    343 	void *addr;
    344 	int blk;
    345 {
    346 	if (blk > NBPG)
    347 		blk = NBPG;
    348 	return (blk);
    349 }
    350 
    351 #define ROUND(s)  ( ((int)s) & (~(NBPG-1)) )
    352 
    353 int
    354 vidcaudio_start_output(addr, p, cc, intr, arg)
    355 	void *addr;
    356 	void *p;
    357 	int cc;
    358 	void (*intr)(void *);
    359 	void *arg;
    360 {
    361 	/* I can only DMA inside 1 page */
    362 
    363 #ifdef DEBUG
    364 	printf("vidcaudio_start_output (%d) %08x %08x\n", cc, intr, arg);
    365 #endif
    366 
    367 	if (ROUND(p) != ROUND(p+cc)) {
    368 		/*
    369 		 * If it's over a page I can fix it up by copying it into
    370 		 * my buffer
    371 		 */
    372 
    373 #ifdef DEBUG
    374 		printf("vidcaudio: DMA over page boundary requested."
    375 		    "  Fixing up\n");
    376 #endif
    377 		memcpy(p, (char *)ag.silence, cc > NBPG ? NBPG : cc);
    378 		p = (void *)ag.silence;
    379 
    380 		/*
    381 		 * I can't DMA any more than that, but it is possible to
    382 		 * fix it up by handling multiple buffers and only
    383 		 * interrupting the audio driver after sending out all the
    384 		 * stuff it gave me.  That it more than I can be bothered
    385 		 * to do right now and it probablly wont happen so I'll just
    386 		 * truncate the buffer and tell the user.
    387 		 */
    388 
    389 		if (cc > NBPG) {
    390 			printf("vidcaudio: DMA buffer truncated. I could fix this up\n");
    391 			cc = NBPG;
    392 		}
    393 	}
    394 	vidcaudio_dma_program((vaddr_t)p, (vaddr_t)((char *)p+cc),
    395 	    intr, arg);
    396 	return 0;
    397 }
    398 
    399 int
    400 vidcaudio_start_input(addr, p, cc, intr, arg)
    401 	void *addr;
    402 	void *p;
    403 	int cc;
    404 	void (*intr)(void *);
    405 	void *arg;
    406 {
    407 	return EIO;
    408 }
    409 
    410 int
    411 vidcaudio_halt_output(addr)
    412 	void *addr;
    413 {
    414 #ifdef DEBUG
    415 	printf("DEBUG: vidcaudio_halt_output\n");
    416 #endif
    417 	return EIO;
    418 }
    419 
    420 int
    421 vidcaudio_halt_input(addr)
    422 	void *addr;
    423 {
    424 #ifdef DEBUG
    425 	printf("DEBUG: vidcaudio_halt_input\n");
    426 #endif
    427 	return EIO;
    428 }
    429 
    430 int
    431 vidcaudio_speaker_ctl(addr, newstate)
    432 	void *addr;
    433 	int newstate;
    434 {
    435 #ifdef DEBUG
    436 	printf("DEBUG: vidcaudio_speaker_ctl\n");
    437 #endif
    438 	return 0;
    439 }
    440 
    441 int
    442 vidcaudio_getdev(addr, retp)
    443 	void *addr;
    444 	struct audio_device *retp;
    445 {
    446 	*retp = vidcaudio_device;
    447 	return 0;
    448 }
    449 
    450 
    451 int
    452 vidcaudio_set_port(addr, cp)
    453 	void *addr;
    454 	mixer_ctrl_t *cp;
    455 {
    456 	return EINVAL;
    457 }
    458 
    459 int
    460 vidcaudio_get_port(addr, cp)
    461 	void *addr;
    462 	mixer_ctrl_t *cp;
    463 {
    464 	return EINVAL;
    465 }
    466 
    467 int
    468 vidcaudio_query_devinfo(addr, dip)
    469 	void *addr;
    470 	mixer_devinfo_t *dip;
    471 {
    472 	return ENXIO;
    473 }
    474 
    475 int
    476 vidcaudio_get_props(addr)
    477 	void *addr;
    478 {
    479 	return 0;
    480 }
    481 void
    482 vidcaudio_dummy_routine(arg)
    483 	void *arg;
    484 {
    485 #ifdef DEBUG
    486 	printf("vidcaudio_dummy_routine\n");
    487 #endif
    488 }
    489 
    490 int
    491 vidcaudio_rate(rate)
    492 	int rate;
    493 {
    494 	WriteWord(vidc_base, VIDC_SFR | rate);
    495 	return 0;
    496 }
    497 
    498 int
    499 vidcaudio_stereo(channel, position)
    500 	int channel;
    501 	int position;
    502 {
    503 	if (channel < 0) return EINVAL;
    504 	if (channel > 7) return EINVAL;
    505 	channel = channel<<24 | VIDC_SIR0;
    506 	WriteWord(vidc_base, channel | position);
    507 	return 0;
    508 }
    509 
    510 #define PHYS(x, y) pmap_extract(pmap_kernel(), ((x)&L2_S_FRAME), (paddr_t *)(y))
    511 
    512 /*
    513  * Program the next buffer to be used
    514  * This function must be re-entrant, maximum re-entrancy of 2
    515  */
    516 
    517 #define FLAGS (0)
    518 
    519 int
    520 vidcaudio_dma_program(cur, end, intr, arg)
    521 	vaddr_t cur;
    522 	vaddr_t end;
    523 	void (*intr)(void *);
    524 	void *arg;
    525 {
    526 	paddr_t pa1, pa2;
    527 
    528 	/* If there isn't a transfer in progress then start a new one */
    529 	if (ag.in_progress == 0) {
    530 		ag.buffer = 0;
    531 		IOMD_WRITE_WORD(IOMD_SD0CR, 0x90);	/* Reset State Machine */
    532 		IOMD_WRITE_WORD(IOMD_SD0CR, 0x30);	/* Reset State Machine */
    533 
    534 		PHYS(cur, &pa1);
    535 		PHYS(end - 16, &pa2);
    536 
    537 		IOMD_WRITE_WORD(IOMD_SD0CURB, pa1);
    538 		IOMD_WRITE_WORD(IOMD_SD0ENDB, pa2|FLAGS);
    539 		IOMD_WRITE_WORD(IOMD_SD0CURA, pa1);
    540 		IOMD_WRITE_WORD(IOMD_SD0ENDA, pa2|FLAGS);
    541 
    542 		ag.in_progress = 1;
    543 
    544 		ag.next_cur = ag.next_end = 0;
    545 		ag.next_intr = ag.next_arg = 0;
    546 
    547 		ag.intr = intr;
    548 		ag.arg = arg;
    549 
    550 		/*
    551 		 * The driver 'clicks' between buffer swaps, leading me
    552 		 * to think  that the fifo is much small than on other
    553 		 * sound cards so I'm going to have to do some tricks here
    554 		 */
    555 
    556 		(*ag.intr)(ag.arg);			/* Schedule the next buffer */
    557 		ag.intr = vidcaudio_dummy_routine;	/* Already done this        */
    558 		ag.arg = NULL;
    559 
    560 #ifdef PRINT
    561 		printf("vidcaudio: start output\n");
    562 #endif
    563 #ifdef DEBUG
    564 		printf("SE");
    565 #endif
    566 		enable_irq(sound_dma_intr);
    567 	} else {
    568 		/* Otherwise schedule the next one */
    569 		if (ag.next_cur != 0) {
    570 			/* If there's one scheduled then complain */
    571 			printf("vidcaudio: Buffer already Q'ed\n");
    572 			return EIO;
    573 		} else {
    574 			/* We're OK to schedule it now */
    575 			ag.buffer = (++ag.buffer) & 1;
    576 			PHYS(cur, &ag.next_cur);
    577 			PHYS(end - 16, &ag.next_end);
    578 			ag.next_intr = intr;
    579 			ag.next_arg = arg;
    580 #ifdef DEBUG
    581 			printf("s");
    582 #endif
    583 		}
    584 	}
    585 	return 0;
    586 }
    587 
    588 void
    589 vidcaudio_shutdown(void)
    590 {
    591 	/* Shut down the channel */
    592 	ag.intr = NULL;
    593 	ag.in_progress = 0;
    594 #ifdef PRINT
    595 	printf("vidcaudio: stop output\n");
    596 #endif
    597 	IOMD_WRITE_WORD(IOMD_SD0CURB, ag.silence);
    598 	IOMD_WRITE_WORD(IOMD_SD0ENDB, (ag.silence + NBPG - 16) | (1<<30));
    599 	disable_irq(sound_dma_intr);
    600 }
    601 
    602 int
    603 vidcaudio_intr(arg)
    604 	void *arg;
    605 {
    606 	int status = IOMD_READ_BYTE(IOMD_SD0ST);
    607 	void (*nintr)(void *);
    608 	void *narg;
    609 	void (*xintr)(void *);
    610 	void *xarg;
    611 	int xcur, xend;
    612 	IOMD_WRITE_WORD(IOMD_DMARQ, 0x10);
    613 
    614 #ifdef PRINT
    615 	printf ( "I" );
    616 #endif
    617 
    618 	if (ag.open == 0) {
    619 		vidcaudio_shutdown();
    620 		return 0;
    621 	}
    622 
    623 	/* Have I got the generic audio device attached */
    624 
    625 #ifdef DEBUG
    626 	printf ( "[B%01x]", status );
    627 #endif
    628 
    629 	nintr = ag.intr;
    630 	narg = ag.arg;
    631 	ag.intr = NULL;
    632 
    633 	xintr = ag.next_intr;
    634 	xarg = ag.next_arg;
    635 	xcur = ag.next_cur;
    636 	xend = ag.next_end;
    637 	ag.next_cur = 0;
    638 	ag.intr = xintr;
    639 	ag.arg = xarg;
    640 
    641 	if (nintr) {
    642 #ifdef DEBUG
    643 		printf("i");
    644 #endif
    645 		(*nintr)(narg);
    646 	}
    647 
    648 	if (xcur == 0) {
    649 		vidcaudio_shutdown ();
    650 	} else {
    651 #define OVERRUN 	(0x04)
    652 #define INTERRUPT	(0x02)
    653 #define BANK_A		(0x00)
    654 #define BANK_B		(0x01)
    655 		switch (status & 0x7) {
    656 		case (INTERRUPT|BANK_A):
    657 #ifdef PRINT
    658 			printf("B");
    659 #endif
    660 			IOMD_WRITE_WORD(IOMD_SD0CURB, xcur);
    661 			IOMD_WRITE_WORD(IOMD_SD0ENDB, xend|FLAGS);
    662 			break;
    663 
    664 		case (INTERRUPT|BANK_B):
    665 #ifdef PRINT
    666 			printf("A");
    667 #endif
    668 			IOMD_WRITE_WORD(IOMD_SD0CURA, xcur);
    669 			IOMD_WRITE_WORD(IOMD_SD0ENDA, xend|FLAGS);
    670 			break;
    671 
    672 		case (OVERRUN|INTERRUPT|BANK_A):
    673 #ifdef PRINT
    674 			printf("A");
    675 #endif
    676 			IOMD_WRITE_WORD(IOMD_SD0CURA, xcur);
    677 			IOMD_WRITE_WORD(IOMD_SD0ENDA, xend|FLAGS);
    678 			break;
    679 
    680 		case (OVERRUN|INTERRUPT|BANK_B):
    681 #ifdef PRINT
    682 			printf("B");
    683 #endif
    684 			IOMD_WRITE_WORD(IOMD_SD0CURB, xcur);
    685 			IOMD_WRITE_WORD(IOMD_SD0ENDB, xend|FLAGS);
    686 			break;
    687 		}
    688 /*
    689 	ag.next_cur = 0;
    690 	ag.intr = xintr;
    691 	ag.arg = xarg;
    692 */
    693 	}
    694 #ifdef PRINT
    695 	printf ( "i" );
    696 #endif
    697 
    698 	if (ag.next_cur == 0) {
    699 		(*ag.intr)(ag.arg);			/* Schedule the next buffer */
    700 		ag.intr = vidcaudio_dummy_routine;	/* Already done this        */
    701 		ag.arg = NULL;
    702 	}
    703 	return(0);	/* Pass interrupt on down the chain */
    704 }
    705