xref: /openbmc/linux/sound/isa/sb/sb8_main.c (revision 384740dc)
1 /*
2  *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
3  *                   Uros Bizjak <uros@kss-loka.si>
4  *
5  *  Routines for control of 8-bit SoundBlaster cards and clones
6  *  Please note: I don't have access to old SB8 soundcards.
7  *
8  *
9  *   This program is free software; you can redistribute it and/or modify
10  *   it under the terms of the GNU General Public License as published by
11  *   the Free Software Foundation; either version 2 of the License, or
12  *   (at your option) any later version.
13  *
14  *   This program is distributed in the hope that it will be useful,
15  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
16  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
17  *   GNU General Public License for more details.
18  *
19  *   You should have received a copy of the GNU General Public License
20  *   along with this program; if not, write to the Free Software
21  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
22  *
23  * --
24  *
25  * Thu Apr 29 20:36:17 BST 1999 George David Morrison <gdm@gedamo.demon.co.uk>
26  *   DSP can't respond to commands whilst in "high speed" mode. Caused
27  *   glitching during playback. Fixed.
28  *
29  * Wed Jul 12 22:02:55 CEST 2000 Uros Bizjak <uros@kss-loka.si>
30  *   Cleaned up and rewrote lowlevel routines.
31  */
32 
33 #include <asm/io.h>
34 #include <asm/dma.h>
35 #include <linux/init.h>
36 #include <linux/time.h>
37 #include <sound/core.h>
38 #include <sound/sb.h>
39 
40 MODULE_AUTHOR("Jaroslav Kysela <perex@perex.cz>, Uros Bizjak <uros@kss-loka.si>");
41 MODULE_DESCRIPTION("Routines for control of 8-bit SoundBlaster cards and clones");
42 MODULE_LICENSE("GPL");
43 
44 #define SB8_CLOCK	1000000
45 #define SB8_DEN(v)	((SB8_CLOCK + (v) / 2) / (v))
46 #define SB8_RATE(v)	(SB8_CLOCK / SB8_DEN(v))
47 
48 static struct snd_ratnum clock = {
49 	.num = SB8_CLOCK,
50 	.den_min = 1,
51 	.den_max = 256,
52 	.den_step = 1,
53 };
54 
55 static struct snd_pcm_hw_constraint_ratnums hw_constraints_clock = {
56 	.nrats = 1,
57 	.rats = &clock,
58 };
59 
60 static struct snd_ratnum stereo_clocks[] = {
61 	{
62 		.num = SB8_CLOCK,
63 		.den_min = SB8_DEN(22050),
64 		.den_max = SB8_DEN(22050),
65 		.den_step = 1,
66 	},
67 	{
68 		.num = SB8_CLOCK,
69 		.den_min = SB8_DEN(11025),
70 		.den_max = SB8_DEN(11025),
71 		.den_step = 1,
72 	}
73 };
74 
75 static int snd_sb8_hw_constraint_rate_channels(struct snd_pcm_hw_params *params,
76 					       struct snd_pcm_hw_rule *rule)
77 {
78 	struct snd_interval *c = hw_param_interval(params, SNDRV_PCM_HW_PARAM_CHANNELS);
79 	if (c->min > 1) {
80 	  	unsigned int num = 0, den = 0;
81 		int err = snd_interval_ratnum(hw_param_interval(params, SNDRV_PCM_HW_PARAM_RATE),
82 					  2, stereo_clocks, &num, &den);
83 		if (err >= 0 && den) {
84 			params->rate_num = num;
85 			params->rate_den = den;
86 		}
87 		return err;
88 	}
89 	return 0;
90 }
91 
92 static int snd_sb8_hw_constraint_channels_rate(struct snd_pcm_hw_params *params,
93 					       struct snd_pcm_hw_rule *rule)
94 {
95 	struct snd_interval *r = hw_param_interval(params, SNDRV_PCM_HW_PARAM_RATE);
96 	if (r->min > SB8_RATE(22050) || r->max <= SB8_RATE(11025)) {
97 		struct snd_interval t = { .min = 1, .max = 1 };
98 		return snd_interval_refine(hw_param_interval(params, SNDRV_PCM_HW_PARAM_CHANNELS), &t);
99 	}
100 	return 0;
101 }
102 
103 static int snd_sb8_playback_prepare(struct snd_pcm_substream *substream)
104 {
105 	unsigned long flags;
106 	struct snd_sb *chip = snd_pcm_substream_chip(substream);
107 	struct snd_pcm_runtime *runtime = substream->runtime;
108 	unsigned int mixreg, rate, size, count;
109 
110 	rate = runtime->rate;
111 	switch (chip->hardware) {
112 	case SB_HW_PRO:
113 		if (runtime->channels > 1) {
114 			snd_assert(rate == SB8_RATE(11025) || rate == SB8_RATE(22050), return -EINVAL);
115 			chip->playback_format = SB_DSP_HI_OUTPUT_AUTO;
116 			break;
117 		}
118 		/* fallthru */
119 	case SB_HW_201:
120 		if (rate > 23000) {
121 			chip->playback_format = SB_DSP_HI_OUTPUT_AUTO;
122 			break;
123 		}
124 		/* fallthru */
125 	case SB_HW_20:
126 		chip->playback_format = SB_DSP_LO_OUTPUT_AUTO;
127 		break;
128 	case SB_HW_10:
129 		chip->playback_format = SB_DSP_OUTPUT;
130 		break;
131 	default:
132 		return -EINVAL;
133 	}
134 	size = chip->p_dma_size = snd_pcm_lib_buffer_bytes(substream);
135 	count = chip->p_period_size = snd_pcm_lib_period_bytes(substream);
136 	spin_lock_irqsave(&chip->reg_lock, flags);
137 	snd_sbdsp_command(chip, SB_DSP_SPEAKER_ON);
138 	if (runtime->channels > 1) {
139 		/* set playback stereo mode */
140 		spin_lock(&chip->mixer_lock);
141 		mixreg = snd_sbmixer_read(chip, SB_DSP_STEREO_SW);
142 		snd_sbmixer_write(chip, SB_DSP_STEREO_SW, mixreg | 0x02);
143 		spin_unlock(&chip->mixer_lock);
144 
145 		/* Soundblaster hardware programming reference guide, 3-23 */
146 		snd_sbdsp_command(chip, SB_DSP_DMA8_EXIT);
147 		runtime->dma_area[0] = 0x80;
148 		snd_dma_program(chip->dma8, runtime->dma_addr, 1, DMA_MODE_WRITE);
149 		/* force interrupt */
150 		chip->mode = SB_MODE_HALT;
151 		snd_sbdsp_command(chip, SB_DSP_OUTPUT);
152 		snd_sbdsp_command(chip, 0);
153 		snd_sbdsp_command(chip, 0);
154 	}
155 	snd_sbdsp_command(chip, SB_DSP_SAMPLE_RATE);
156 	if (runtime->channels > 1) {
157 		snd_sbdsp_command(chip, 256 - runtime->rate_den / 2);
158 		spin_lock(&chip->mixer_lock);
159 		/* save output filter status and turn it off */
160 		mixreg = snd_sbmixer_read(chip, SB_DSP_PLAYBACK_FILT);
161 		snd_sbmixer_write(chip, SB_DSP_PLAYBACK_FILT, mixreg | 0x20);
162 		spin_unlock(&chip->mixer_lock);
163 		/* just use force_mode16 for temporary storate... */
164 		chip->force_mode16 = mixreg;
165 	} else {
166 		snd_sbdsp_command(chip, 256 - runtime->rate_den);
167 	}
168 	if (chip->playback_format != SB_DSP_OUTPUT) {
169 		count--;
170 		snd_sbdsp_command(chip, SB_DSP_BLOCK_SIZE);
171 		snd_sbdsp_command(chip, count & 0xff);
172 		snd_sbdsp_command(chip, count >> 8);
173 	}
174 	spin_unlock_irqrestore(&chip->reg_lock, flags);
175 	snd_dma_program(chip->dma8, runtime->dma_addr,
176 			size, DMA_MODE_WRITE | DMA_AUTOINIT);
177 	return 0;
178 }
179 
180 static int snd_sb8_playback_trigger(struct snd_pcm_substream *substream,
181 				    int cmd)
182 {
183 	unsigned long flags;
184 	struct snd_sb *chip = snd_pcm_substream_chip(substream);
185 	unsigned int count;
186 
187 	spin_lock_irqsave(&chip->reg_lock, flags);
188 	switch (cmd) {
189 	case SNDRV_PCM_TRIGGER_START:
190 		snd_sbdsp_command(chip, chip->playback_format);
191 		if (chip->playback_format == SB_DSP_OUTPUT) {
192 			count = chip->p_period_size - 1;
193 			snd_sbdsp_command(chip, count & 0xff);
194 			snd_sbdsp_command(chip, count >> 8);
195 		}
196 		break;
197 	case SNDRV_PCM_TRIGGER_STOP:
198 		if (chip->playback_format == SB_DSP_HI_OUTPUT_AUTO) {
199 			struct snd_pcm_runtime *runtime = substream->runtime;
200 			snd_sbdsp_reset(chip);
201 			if (runtime->channels > 1) {
202 				spin_lock(&chip->mixer_lock);
203 				/* restore output filter and set hardware to mono mode */
204 				snd_sbmixer_write(chip, SB_DSP_STEREO_SW, chip->force_mode16 & ~0x02);
205 				spin_unlock(&chip->mixer_lock);
206 			}
207 		} else {
208 			snd_sbdsp_command(chip, SB_DSP_DMA8_OFF);
209 		}
210 		snd_sbdsp_command(chip, SB_DSP_SPEAKER_OFF);
211 	}
212 	spin_unlock_irqrestore(&chip->reg_lock, flags);
213 	chip->mode = (cmd == SNDRV_PCM_TRIGGER_START) ? SB_MODE_PLAYBACK_8 : SB_MODE_HALT;
214 	return 0;
215 }
216 
217 static int snd_sb8_hw_params(struct snd_pcm_substream *substream,
218 			     struct snd_pcm_hw_params *hw_params)
219 {
220 	return snd_pcm_lib_malloc_pages(substream, params_buffer_bytes(hw_params));
221 }
222 
223 static int snd_sb8_hw_free(struct snd_pcm_substream *substream)
224 {
225 	snd_pcm_lib_free_pages(substream);
226 	return 0;
227 }
228 
229 static int snd_sb8_capture_prepare(struct snd_pcm_substream *substream)
230 {
231 	unsigned long flags;
232 	struct snd_sb *chip = snd_pcm_substream_chip(substream);
233 	struct snd_pcm_runtime *runtime = substream->runtime;
234 	unsigned int mixreg, rate, size, count;
235 
236 	rate = runtime->rate;
237 	switch (chip->hardware) {
238 	case SB_HW_PRO:
239 		if (runtime->channels > 1) {
240 			snd_assert(rate == SB8_RATE(11025) || rate == SB8_RATE(22050), return -EINVAL);
241 			chip->capture_format = SB_DSP_HI_INPUT_AUTO;
242 			break;
243 		}
244 		chip->capture_format = (rate > 23000) ? SB_DSP_HI_INPUT_AUTO : SB_DSP_LO_INPUT_AUTO;
245 		break;
246 	case SB_HW_201:
247 		if (rate > 13000) {
248 			chip->capture_format = SB_DSP_HI_INPUT_AUTO;
249 			break;
250 		}
251 		/* fallthru */
252 	case SB_HW_20:
253 		chip->capture_format = SB_DSP_LO_INPUT_AUTO;
254 		break;
255 	case SB_HW_10:
256 		chip->capture_format = SB_DSP_INPUT;
257 		break;
258 	default:
259 		return -EINVAL;
260 	}
261 	size = chip->c_dma_size = snd_pcm_lib_buffer_bytes(substream);
262 	count = chip->c_period_size = snd_pcm_lib_period_bytes(substream);
263 	spin_lock_irqsave(&chip->reg_lock, flags);
264 	snd_sbdsp_command(chip, SB_DSP_SPEAKER_OFF);
265 	if (runtime->channels > 1)
266 		snd_sbdsp_command(chip, SB_DSP_STEREO_8BIT);
267 	snd_sbdsp_command(chip, SB_DSP_SAMPLE_RATE);
268 	if (runtime->channels > 1) {
269 		snd_sbdsp_command(chip, 256 - runtime->rate_den / 2);
270 		spin_lock(&chip->mixer_lock);
271 		/* save input filter status and turn it off */
272 		mixreg = snd_sbmixer_read(chip, SB_DSP_CAPTURE_FILT);
273 		snd_sbmixer_write(chip, SB_DSP_CAPTURE_FILT, mixreg | 0x20);
274 		spin_unlock(&chip->mixer_lock);
275 		/* just use force_mode16 for temporary storate... */
276 		chip->force_mode16 = mixreg;
277 	} else {
278 		snd_sbdsp_command(chip, 256 - runtime->rate_den);
279 	}
280 	if (chip->capture_format != SB_DSP_INPUT) {
281 		count--;
282 		snd_sbdsp_command(chip, SB_DSP_BLOCK_SIZE);
283 		snd_sbdsp_command(chip, count & 0xff);
284 		snd_sbdsp_command(chip, count >> 8);
285 	}
286 	spin_unlock_irqrestore(&chip->reg_lock, flags);
287 	snd_dma_program(chip->dma8, runtime->dma_addr,
288 			size, DMA_MODE_READ | DMA_AUTOINIT);
289 	return 0;
290 }
291 
292 static int snd_sb8_capture_trigger(struct snd_pcm_substream *substream,
293 				   int cmd)
294 {
295 	unsigned long flags;
296 	struct snd_sb *chip = snd_pcm_substream_chip(substream);
297 	unsigned int count;
298 
299 	spin_lock_irqsave(&chip->reg_lock, flags);
300 	switch (cmd) {
301 	case SNDRV_PCM_TRIGGER_START:
302 		snd_sbdsp_command(chip, chip->capture_format);
303 		if (chip->capture_format == SB_DSP_INPUT) {
304 			count = chip->c_period_size - 1;
305 			snd_sbdsp_command(chip, count & 0xff);
306 			snd_sbdsp_command(chip, count >> 8);
307 		}
308 		break;
309 	case SNDRV_PCM_TRIGGER_STOP:
310 		if (chip->capture_format == SB_DSP_HI_INPUT_AUTO) {
311 			struct snd_pcm_runtime *runtime = substream->runtime;
312 			snd_sbdsp_reset(chip);
313 			if (runtime->channels > 1) {
314 				/* restore input filter status */
315 				spin_lock(&chip->mixer_lock);
316 				snd_sbmixer_write(chip, SB_DSP_CAPTURE_FILT, chip->force_mode16);
317 				spin_unlock(&chip->mixer_lock);
318 				/* set hardware to mono mode */
319 				snd_sbdsp_command(chip, SB_DSP_MONO_8BIT);
320 			}
321 		} else {
322 			snd_sbdsp_command(chip, SB_DSP_DMA8_OFF);
323 		}
324 		snd_sbdsp_command(chip, SB_DSP_SPEAKER_OFF);
325 	}
326 	spin_unlock_irqrestore(&chip->reg_lock, flags);
327 	chip->mode = (cmd == SNDRV_PCM_TRIGGER_START) ? SB_MODE_CAPTURE_8 : SB_MODE_HALT;
328 	return 0;
329 }
330 
331 irqreturn_t snd_sb8dsp_interrupt(struct snd_sb *chip)
332 {
333 	struct snd_pcm_substream *substream;
334 	struct snd_pcm_runtime *runtime;
335 
336 	snd_sb_ack_8bit(chip);
337 	switch (chip->mode) {
338 	case SB_MODE_PLAYBACK_8:	/* ok.. playback is active */
339 		substream = chip->playback_substream;
340 		runtime = substream->runtime;
341 		if (chip->playback_format == SB_DSP_OUTPUT)
342 		    	snd_sb8_playback_trigger(substream, SNDRV_PCM_TRIGGER_START);
343 		snd_pcm_period_elapsed(substream);
344 		break;
345 	case SB_MODE_CAPTURE_8:
346 		substream = chip->capture_substream;
347 		runtime = substream->runtime;
348 		if (chip->capture_format == SB_DSP_INPUT)
349 		    	snd_sb8_capture_trigger(substream, SNDRV_PCM_TRIGGER_START);
350 		snd_pcm_period_elapsed(substream);
351 		break;
352 	}
353 	return IRQ_HANDLED;
354 }
355 
356 static snd_pcm_uframes_t snd_sb8_playback_pointer(struct snd_pcm_substream *substream)
357 {
358 	struct snd_sb *chip = snd_pcm_substream_chip(substream);
359 	size_t ptr;
360 
361 	if (chip->mode != SB_MODE_PLAYBACK_8)
362 		return 0;
363 	ptr = snd_dma_pointer(chip->dma8, chip->p_dma_size);
364 	return bytes_to_frames(substream->runtime, ptr);
365 }
366 
367 static snd_pcm_uframes_t snd_sb8_capture_pointer(struct snd_pcm_substream *substream)
368 {
369 	struct snd_sb *chip = snd_pcm_substream_chip(substream);
370 	size_t ptr;
371 
372 	if (chip->mode != SB_MODE_CAPTURE_8)
373 		return 0;
374 	ptr = snd_dma_pointer(chip->dma8, chip->c_dma_size);
375 	return bytes_to_frames(substream->runtime, ptr);
376 }
377 
378 /*
379 
380  */
381 
382 static struct snd_pcm_hardware snd_sb8_playback =
383 {
384 	.info =			(SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_INTERLEAVED |
385 				 SNDRV_PCM_INFO_MMAP_VALID),
386 	.formats =		 SNDRV_PCM_FMTBIT_U8,
387 	.rates =		(SNDRV_PCM_RATE_CONTINUOUS | SNDRV_PCM_RATE_8000 |
388 				 SNDRV_PCM_RATE_11025 | SNDRV_PCM_RATE_22050),
389 	.rate_min =		4000,
390 	.rate_max =		23000,
391 	.channels_min =		1,
392 	.channels_max =		1,
393 	.buffer_bytes_max =	65536,
394 	.period_bytes_min =	64,
395 	.period_bytes_max =	65536,
396 	.periods_min =		1,
397 	.periods_max =		1024,
398 	.fifo_size =		0,
399 };
400 
401 static struct snd_pcm_hardware snd_sb8_capture =
402 {
403 	.info =			(SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_INTERLEAVED |
404 				 SNDRV_PCM_INFO_MMAP_VALID),
405 	.formats =		SNDRV_PCM_FMTBIT_U8,
406 	.rates =		(SNDRV_PCM_RATE_CONTINUOUS | SNDRV_PCM_RATE_8000 |
407 				 SNDRV_PCM_RATE_11025),
408 	.rate_min =		4000,
409 	.rate_max =		13000,
410 	.channels_min =		1,
411 	.channels_max =		1,
412 	.buffer_bytes_max =	65536,
413 	.period_bytes_min =	64,
414 	.period_bytes_max =	65536,
415 	.periods_min =		1,
416 	.periods_max =		1024,
417 	.fifo_size =		0,
418 };
419 
420 /*
421  *
422  */
423 
424 static int snd_sb8_open(struct snd_pcm_substream *substream)
425 {
426 	struct snd_sb *chip = snd_pcm_substream_chip(substream);
427 	struct snd_pcm_runtime *runtime = substream->runtime;
428 	unsigned long flags;
429 
430 	spin_lock_irqsave(&chip->open_lock, flags);
431 	if (chip->open) {
432 		spin_unlock_irqrestore(&chip->open_lock, flags);
433 		return -EAGAIN;
434 	}
435 	chip->open |= SB_OPEN_PCM;
436 	spin_unlock_irqrestore(&chip->open_lock, flags);
437 	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
438 		chip->playback_substream = substream;
439 		runtime->hw = snd_sb8_playback;
440 	} else {
441 		chip->capture_substream = substream;
442 		runtime->hw = snd_sb8_capture;
443 	}
444 	switch (chip->hardware) {
445 	case SB_HW_PRO:
446 		runtime->hw.rate_max = 44100;
447 		runtime->hw.channels_max = 2;
448 		snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_RATE,
449 				    snd_sb8_hw_constraint_rate_channels, NULL,
450 				    SNDRV_PCM_HW_PARAM_CHANNELS,
451 				    SNDRV_PCM_HW_PARAM_RATE, -1);
452 		snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_CHANNELS,
453 				     snd_sb8_hw_constraint_channels_rate, NULL,
454 				     SNDRV_PCM_HW_PARAM_RATE, -1);
455 		break;
456 	case SB_HW_201:
457 		if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
458 			runtime->hw.rate_max = 44100;
459 		} else {
460 			runtime->hw.rate_max = 15000;
461 		}
462 	default:
463 		break;
464 	}
465 	snd_pcm_hw_constraint_ratnums(runtime, 0, SNDRV_PCM_HW_PARAM_RATE,
466 				      &hw_constraints_clock);
467 	return 0;
468 }
469 
470 static int snd_sb8_close(struct snd_pcm_substream *substream)
471 {
472 	unsigned long flags;
473 	struct snd_sb *chip = snd_pcm_substream_chip(substream);
474 
475 	chip->playback_substream = NULL;
476 	chip->capture_substream = NULL;
477 	spin_lock_irqsave(&chip->open_lock, flags);
478 	chip->open &= ~SB_OPEN_PCM;
479 	spin_unlock_irqrestore(&chip->open_lock, flags);
480 	return 0;
481 }
482 
483 /*
484  *  Initialization part
485  */
486 
487 static struct snd_pcm_ops snd_sb8_playback_ops = {
488 	.open =			snd_sb8_open,
489 	.close =		snd_sb8_close,
490 	.ioctl =		snd_pcm_lib_ioctl,
491 	.hw_params =		snd_sb8_hw_params,
492 	.hw_free =		snd_sb8_hw_free,
493 	.prepare =		snd_sb8_playback_prepare,
494 	.trigger =		snd_sb8_playback_trigger,
495 	.pointer =		snd_sb8_playback_pointer,
496 };
497 
498 static struct snd_pcm_ops snd_sb8_capture_ops = {
499 	.open =			snd_sb8_open,
500 	.close =		snd_sb8_close,
501 	.ioctl =		snd_pcm_lib_ioctl,
502 	.hw_params =		snd_sb8_hw_params,
503 	.hw_free =		snd_sb8_hw_free,
504 	.prepare =		snd_sb8_capture_prepare,
505 	.trigger =		snd_sb8_capture_trigger,
506 	.pointer =		snd_sb8_capture_pointer,
507 };
508 
509 int snd_sb8dsp_pcm(struct snd_sb *chip, int device, struct snd_pcm ** rpcm)
510 {
511 	struct snd_card *card = chip->card;
512 	struct snd_pcm *pcm;
513 	int err;
514 
515 	if (rpcm)
516 		*rpcm = NULL;
517 	if ((err = snd_pcm_new(card, "SB8 DSP", device, 1, 1, &pcm)) < 0)
518 		return err;
519 	sprintf(pcm->name, "DSP v%i.%i", chip->version >> 8, chip->version & 0xff);
520 	pcm->info_flags = SNDRV_PCM_INFO_HALF_DUPLEX;
521 	pcm->private_data = chip;
522 
523 	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &snd_sb8_playback_ops);
524 	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &snd_sb8_capture_ops);
525 
526 	snd_pcm_lib_preallocate_pages_for_all(pcm, SNDRV_DMA_TYPE_DEV,
527 					      snd_dma_isa_data(),
528 					      64*1024, 64*1024);
529 
530 	if (rpcm)
531 		*rpcm = pcm;
532 	return 0;
533 }
534 
535 EXPORT_SYMBOL(snd_sb8dsp_pcm);
536 EXPORT_SYMBOL(snd_sb8dsp_interrupt);
537   /* sb8_midi.c */
538 EXPORT_SYMBOL(snd_sb8dsp_midi_interrupt);
539 EXPORT_SYMBOL(snd_sb8dsp_midi);
540 
541 /*
542  *  INIT part
543  */
544 
545 static int __init alsa_sb8_init(void)
546 {
547 	return 0;
548 }
549 
550 static void __exit alsa_sb8_exit(void)
551 {
552 }
553 
554 module_init(alsa_sb8_init)
555 module_exit(alsa_sb8_exit)
556