xref: /linux/sound/drivers/mpu401/mpu401_uart.c (revision 827634added7f38b7d724cab1dccdb2b004c13c3) 
1 /*
2  *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
3  *  Routines for control of MPU-401 in UART mode
4  *
5  *  MPU-401 supports UART mode which is not capable generate transmit
6  *  interrupts thus output is done via polling. Without interrupt,
7  *  input is done also via polling. Do not expect good performance.
8  *
9  *
10  *   This program is free software; you can redistribute it and/or modify
11  *   it under the terms of the GNU General Public License as published by
12  *   the Free Software Foundation; either version 2 of the License, or
13  *   (at your option) any later version.
14  *
15  *   This program is distributed in the hope that it will be useful,
16  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
17  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
18  *   GNU General Public License for more details.
19  *
20  *   You should have received a copy of the GNU General Public License
21  *   along with this program; if not, write to the Free Software
22  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
23  *
24  *   13-03-2003:
25  *      Added support for different kind of hardware I/O. Build in choices
26  *      are port and mmio. For other kind of I/O, set mpu->read and
27  *      mpu->write to your own I/O functions.
28  *
29  */
30 
31 #include <linux/io.h>
32 #include <linux/delay.h>
33 #include <linux/init.h>
34 #include <linux/slab.h>
35 #include <linux/ioport.h>
36 #include <linux/module.h>
37 #include <linux/interrupt.h>
38 #include <linux/errno.h>
39 #include <sound/core.h>
40 #include <sound/mpu401.h>
41 
42 MODULE_AUTHOR("Jaroslav Kysela <perex@perex.cz>");
43 MODULE_DESCRIPTION("Routines for control of MPU-401 in UART mode");
44 MODULE_LICENSE("GPL");
45 
46 static void snd_mpu401_uart_input_read(struct snd_mpu401 * mpu);
47 static void snd_mpu401_uart_output_write(struct snd_mpu401 * mpu);
48 
49 /*
50 
51  */
52 
53 #define snd_mpu401_input_avail(mpu) \
54 	(!(mpu->read(mpu, MPU401C(mpu)) & MPU401_RX_EMPTY))
55 #define snd_mpu401_output_ready(mpu) \
56 	(!(mpu->read(mpu, MPU401C(mpu)) & MPU401_TX_FULL))
57 
58 /* Build in lowlevel io */
59 static void mpu401_write_port(struct snd_mpu401 *mpu, unsigned char data,
60 			      unsigned long addr)
61 {
62 	outb(data, addr);
63 }
64 
65 static unsigned char mpu401_read_port(struct snd_mpu401 *mpu,
66 				      unsigned long addr)
67 {
68 	return inb(addr);
69 }
70 
71 static void mpu401_write_mmio(struct snd_mpu401 *mpu, unsigned char data,
72 			      unsigned long addr)
73 {
74 	writeb(data, (void __iomem *)addr);
75 }
76 
77 static unsigned char mpu401_read_mmio(struct snd_mpu401 *mpu,
78 				      unsigned long addr)
79 {
80 	return readb((void __iomem *)addr);
81 }
82 /*  */
83 
84 static void snd_mpu401_uart_clear_rx(struct snd_mpu401 *mpu)
85 {
86 	int timeout = 100000;
87 	for (; timeout > 0 && snd_mpu401_input_avail(mpu); timeout--)
88 		mpu->read(mpu, MPU401D(mpu));
89 #ifdef CONFIG_SND_DEBUG
90 	if (timeout <= 0)
91 		snd_printk(KERN_ERR "cmd: clear rx timeout (status = 0x%x)\n",
92 			   mpu->read(mpu, MPU401C(mpu)));
93 #endif
94 }
95 
96 static void uart_interrupt_tx(struct snd_mpu401 *mpu)
97 {
98 	unsigned long flags;
99 
100 	if (test_bit(MPU401_MODE_BIT_OUTPUT, &mpu->mode) &&
101 	    test_bit(MPU401_MODE_BIT_OUTPUT_TRIGGER, &mpu->mode)) {
102 		spin_lock_irqsave(&mpu->output_lock, flags);
103 		snd_mpu401_uart_output_write(mpu);
104 		spin_unlock_irqrestore(&mpu->output_lock, flags);
105 	}
106 }
107 
108 static void _snd_mpu401_uart_interrupt(struct snd_mpu401 *mpu)
109 {
110 	unsigned long flags;
111 
112 	if (mpu->info_flags & MPU401_INFO_INPUT) {
113 		spin_lock_irqsave(&mpu->input_lock, flags);
114 		if (test_bit(MPU401_MODE_BIT_INPUT, &mpu->mode))
115 			snd_mpu401_uart_input_read(mpu);
116 		else
117 			snd_mpu401_uart_clear_rx(mpu);
118 		spin_unlock_irqrestore(&mpu->input_lock, flags);
119 	}
120 	if (! (mpu->info_flags & MPU401_INFO_TX_IRQ))
121 		/* ok. for better Tx performance try do some output
122 		   when input is done */
123 		uart_interrupt_tx(mpu);
124 }
125 
126 /**
127  * snd_mpu401_uart_interrupt - generic MPU401-UART interrupt handler
128  * @irq: the irq number
129  * @dev_id: mpu401 instance
130  *
131  * Processes the interrupt for MPU401-UART i/o.
132  *
133  * Return: %IRQ_HANDLED if the interrupt was handled. %IRQ_NONE otherwise.
134  */
135 irqreturn_t snd_mpu401_uart_interrupt(int irq, void *dev_id)
136 {
137 	struct snd_mpu401 *mpu = dev_id;
138 
139 	if (mpu == NULL)
140 		return IRQ_NONE;
141 	_snd_mpu401_uart_interrupt(mpu);
142 	return IRQ_HANDLED;
143 }
144 
145 EXPORT_SYMBOL(snd_mpu401_uart_interrupt);
146 
147 /**
148  * snd_mpu401_uart_interrupt_tx - generic MPU401-UART transmit irq handler
149  * @irq: the irq number
150  * @dev_id: mpu401 instance
151  *
152  * Processes the interrupt for MPU401-UART output.
153  *
154  * Return: %IRQ_HANDLED if the interrupt was handled. %IRQ_NONE otherwise.
155  */
156 irqreturn_t snd_mpu401_uart_interrupt_tx(int irq, void *dev_id)
157 {
158 	struct snd_mpu401 *mpu = dev_id;
159 
160 	if (mpu == NULL)
161 		return IRQ_NONE;
162 	uart_interrupt_tx(mpu);
163 	return IRQ_HANDLED;
164 }
165 
166 EXPORT_SYMBOL(snd_mpu401_uart_interrupt_tx);
167 
168 /*
169  * timer callback
170  * reprogram the timer and call the interrupt job
171  */
172 static void snd_mpu401_uart_timer(unsigned long data)
173 {
174 	struct snd_mpu401 *mpu = (struct snd_mpu401 *)data;
175 	unsigned long flags;
176 
177 	spin_lock_irqsave(&mpu->timer_lock, flags);
178 	/*mpu->mode |= MPU401_MODE_TIMER;*/
179 	mod_timer(&mpu->timer,  1 + jiffies);
180 	spin_unlock_irqrestore(&mpu->timer_lock, flags);
181 	if (mpu->rmidi)
182 		_snd_mpu401_uart_interrupt(mpu);
183 }
184 
185 /*
186  * initialize the timer callback if not programmed yet
187  */
188 static void snd_mpu401_uart_add_timer (struct snd_mpu401 *mpu, int input)
189 {
190 	unsigned long flags;
191 
192 	spin_lock_irqsave (&mpu->timer_lock, flags);
193 	if (mpu->timer_invoked == 0) {
194 		setup_timer(&mpu->timer, snd_mpu401_uart_timer,
195 			    (unsigned long)mpu);
196 		mod_timer(&mpu->timer, 1 + jiffies);
197 	}
198 	mpu->timer_invoked |= input ? MPU401_MODE_INPUT_TIMER :
199 		MPU401_MODE_OUTPUT_TIMER;
200 	spin_unlock_irqrestore (&mpu->timer_lock, flags);
201 }
202 
203 /*
204  * remove the timer callback if still active
205  */
206 static void snd_mpu401_uart_remove_timer (struct snd_mpu401 *mpu, int input)
207 {
208 	unsigned long flags;
209 
210 	spin_lock_irqsave (&mpu->timer_lock, flags);
211 	if (mpu->timer_invoked) {
212 		mpu->timer_invoked &= input ? ~MPU401_MODE_INPUT_TIMER :
213 			~MPU401_MODE_OUTPUT_TIMER;
214 		if (! mpu->timer_invoked)
215 			del_timer(&mpu->timer);
216 	}
217 	spin_unlock_irqrestore (&mpu->timer_lock, flags);
218 }
219 
220 /*
221  * send a UART command
222  * return zero if successful, non-zero for some errors
223  */
224 
225 static int snd_mpu401_uart_cmd(struct snd_mpu401 * mpu, unsigned char cmd,
226 			       int ack)
227 {
228 	unsigned long flags;
229 	int timeout, ok;
230 
231 	spin_lock_irqsave(&mpu->input_lock, flags);
232 	if (mpu->hardware != MPU401_HW_TRID4DWAVE) {
233 		mpu->write(mpu, 0x00, MPU401D(mpu));
234 		/*snd_mpu401_uart_clear_rx(mpu);*/
235 	}
236 	/* ok. standard MPU-401 initialization */
237 	if (mpu->hardware != MPU401_HW_SB) {
238 		for (timeout = 1000; timeout > 0 &&
239 			     !snd_mpu401_output_ready(mpu); timeout--)
240 			udelay(10);
241 #ifdef CONFIG_SND_DEBUG
242 		if (!timeout)
243 			snd_printk(KERN_ERR "cmd: tx timeout (status = 0x%x)\n",
244 				   mpu->read(mpu, MPU401C(mpu)));
245 #endif
246 	}
247 	mpu->write(mpu, cmd, MPU401C(mpu));
248 	if (ack && !(mpu->info_flags & MPU401_INFO_NO_ACK)) {
249 		ok = 0;
250 		timeout = 10000;
251 		while (!ok && timeout-- > 0) {
252 			if (snd_mpu401_input_avail(mpu)) {
253 				if (mpu->read(mpu, MPU401D(mpu)) == MPU401_ACK)
254 					ok = 1;
255 			}
256 		}
257 		if (!ok && mpu->read(mpu, MPU401D(mpu)) == MPU401_ACK)
258 			ok = 1;
259 	} else
260 		ok = 1;
261 	spin_unlock_irqrestore(&mpu->input_lock, flags);
262 	if (!ok) {
263 		snd_printk(KERN_ERR "cmd: 0x%x failed at 0x%lx "
264 			   "(status = 0x%x, data = 0x%x)\n", cmd, mpu->port,
265 			   mpu->read(mpu, MPU401C(mpu)),
266 			   mpu->read(mpu, MPU401D(mpu)));
267 		return 1;
268 	}
269 	return 0;
270 }
271 
272 static int snd_mpu401_do_reset(struct snd_mpu401 *mpu)
273 {
274 	if (snd_mpu401_uart_cmd(mpu, MPU401_RESET, 1))
275 		return -EIO;
276 	if (snd_mpu401_uart_cmd(mpu, MPU401_ENTER_UART, 0))
277 		return -EIO;
278 	return 0;
279 }
280 
281 /*
282  * input/output open/close - protected by open_mutex in rawmidi.c
283  */
284 static int snd_mpu401_uart_input_open(struct snd_rawmidi_substream *substream)
285 {
286 	struct snd_mpu401 *mpu;
287 	int err;
288 
289 	mpu = substream->rmidi->private_data;
290 	if (mpu->open_input && (err = mpu->open_input(mpu)) < 0)
291 		return err;
292 	if (! test_bit(MPU401_MODE_BIT_OUTPUT, &mpu->mode)) {
293 		if (snd_mpu401_do_reset(mpu) < 0)
294 			goto error_out;
295 	}
296 	mpu->substream_input = substream;
297 	set_bit(MPU401_MODE_BIT_INPUT, &mpu->mode);
298 	return 0;
299 
300 error_out:
301 	if (mpu->open_input && mpu->close_input)
302 		mpu->close_input(mpu);
303 	return -EIO;
304 }
305 
306 static int snd_mpu401_uart_output_open(struct snd_rawmidi_substream *substream)
307 {
308 	struct snd_mpu401 *mpu;
309 	int err;
310 
311 	mpu = substream->rmidi->private_data;
312 	if (mpu->open_output && (err = mpu->open_output(mpu)) < 0)
313 		return err;
314 	if (! test_bit(MPU401_MODE_BIT_INPUT, &mpu->mode)) {
315 		if (snd_mpu401_do_reset(mpu) < 0)
316 			goto error_out;
317 	}
318 	mpu->substream_output = substream;
319 	set_bit(MPU401_MODE_BIT_OUTPUT, &mpu->mode);
320 	return 0;
321 
322 error_out:
323 	if (mpu->open_output && mpu->close_output)
324 		mpu->close_output(mpu);
325 	return -EIO;
326 }
327 
328 static int snd_mpu401_uart_input_close(struct snd_rawmidi_substream *substream)
329 {
330 	struct snd_mpu401 *mpu;
331 	int err = 0;
332 
333 	mpu = substream->rmidi->private_data;
334 	clear_bit(MPU401_MODE_BIT_INPUT, &mpu->mode);
335 	mpu->substream_input = NULL;
336 	if (! test_bit(MPU401_MODE_BIT_OUTPUT, &mpu->mode))
337 		err = snd_mpu401_uart_cmd(mpu, MPU401_RESET, 0);
338 	if (mpu->close_input)
339 		mpu->close_input(mpu);
340 	if (err)
341 		return -EIO;
342 	return 0;
343 }
344 
345 static int snd_mpu401_uart_output_close(struct snd_rawmidi_substream *substream)
346 {
347 	struct snd_mpu401 *mpu;
348 	int err = 0;
349 
350 	mpu = substream->rmidi->private_data;
351 	clear_bit(MPU401_MODE_BIT_OUTPUT, &mpu->mode);
352 	mpu->substream_output = NULL;
353 	if (! test_bit(MPU401_MODE_BIT_INPUT, &mpu->mode))
354 		err = snd_mpu401_uart_cmd(mpu, MPU401_RESET, 0);
355 	if (mpu->close_output)
356 		mpu->close_output(mpu);
357 	if (err)
358 		return -EIO;
359 	return 0;
360 }
361 
362 /*
363  * trigger input callback
364  */
365 static void
366 snd_mpu401_uart_input_trigger(struct snd_rawmidi_substream *substream, int up)
367 {
368 	unsigned long flags;
369 	struct snd_mpu401 *mpu;
370 	int max = 64;
371 
372 	mpu = substream->rmidi->private_data;
373 	if (up) {
374 		if (! test_and_set_bit(MPU401_MODE_BIT_INPUT_TRIGGER,
375 				       &mpu->mode)) {
376 			/* first time - flush FIFO */
377 			while (max-- > 0)
378 				mpu->read(mpu, MPU401D(mpu));
379 			if (mpu->info_flags & MPU401_INFO_USE_TIMER)
380 				snd_mpu401_uart_add_timer(mpu, 1);
381 		}
382 
383 		/* read data in advance */
384 		spin_lock_irqsave(&mpu->input_lock, flags);
385 		snd_mpu401_uart_input_read(mpu);
386 		spin_unlock_irqrestore(&mpu->input_lock, flags);
387 	} else {
388 		if (mpu->info_flags & MPU401_INFO_USE_TIMER)
389 			snd_mpu401_uart_remove_timer(mpu, 1);
390 		clear_bit(MPU401_MODE_BIT_INPUT_TRIGGER, &mpu->mode);
391 	}
392 
393 }
394 
395 /*
396  * transfer input pending data
397  * call with input_lock spinlock held
398  */
399 static void snd_mpu401_uart_input_read(struct snd_mpu401 * mpu)
400 {
401 	int max = 128;
402 	unsigned char byte;
403 
404 	while (max-- > 0) {
405 		if (! snd_mpu401_input_avail(mpu))
406 			break; /* input not available */
407 		byte = mpu->read(mpu, MPU401D(mpu));
408 		if (test_bit(MPU401_MODE_BIT_INPUT_TRIGGER, &mpu->mode))
409 			snd_rawmidi_receive(mpu->substream_input, &byte, 1);
410 	}
411 }
412 
413 /*
414  *  Tx FIFO sizes:
415  *    CS4237B			- 16 bytes
416  *    AudioDrive ES1688         - 12 bytes
417  *    S3 SonicVibes             -  8 bytes
418  *    SoundBlaster AWE 64       -  2 bytes (ugly hardware)
419  */
420 
421 /*
422  * write output pending bytes
423  * call with output_lock spinlock held
424  */
425 static void snd_mpu401_uart_output_write(struct snd_mpu401 * mpu)
426 {
427 	unsigned char byte;
428 	int max = 256;
429 
430 	do {
431 		if (snd_rawmidi_transmit_peek(mpu->substream_output,
432 					      &byte, 1) == 1) {
433 			/*
434 			 * Try twice because there is hardware that insists on
435 			 * setting the output busy bit after each write.
436 			 */
437 			if (!snd_mpu401_output_ready(mpu) &&
438 			    !snd_mpu401_output_ready(mpu))
439 				break;	/* Tx FIFO full - try again later */
440 			mpu->write(mpu, byte, MPU401D(mpu));
441 			snd_rawmidi_transmit_ack(mpu->substream_output, 1);
442 		} else {
443 			snd_mpu401_uart_remove_timer (mpu, 0);
444 			break;	/* no other data - leave the tx loop */
445 		}
446 	} while (--max > 0);
447 }
448 
449 /*
450  * output trigger callback
451  */
452 static void
453 snd_mpu401_uart_output_trigger(struct snd_rawmidi_substream *substream, int up)
454 {
455 	unsigned long flags;
456 	struct snd_mpu401 *mpu;
457 
458 	mpu = substream->rmidi->private_data;
459 	if (up) {
460 		set_bit(MPU401_MODE_BIT_OUTPUT_TRIGGER, &mpu->mode);
461 
462 		/* try to add the timer at each output trigger,
463 		 * since the output timer might have been removed in
464 		 * snd_mpu401_uart_output_write().
465 		 */
466 		if (! (mpu->info_flags & MPU401_INFO_TX_IRQ))
467 			snd_mpu401_uart_add_timer(mpu, 0);
468 
469 		/* output pending data */
470 		spin_lock_irqsave(&mpu->output_lock, flags);
471 		snd_mpu401_uart_output_write(mpu);
472 		spin_unlock_irqrestore(&mpu->output_lock, flags);
473 	} else {
474 		if (! (mpu->info_flags & MPU401_INFO_TX_IRQ))
475 			snd_mpu401_uart_remove_timer(mpu, 0);
476 		clear_bit(MPU401_MODE_BIT_OUTPUT_TRIGGER, &mpu->mode);
477 	}
478 }
479 
480 /*
481 
482  */
483 
484 static struct snd_rawmidi_ops snd_mpu401_uart_output =
485 {
486 	.open =		snd_mpu401_uart_output_open,
487 	.close =	snd_mpu401_uart_output_close,
488 	.trigger =	snd_mpu401_uart_output_trigger,
489 };
490 
491 static struct snd_rawmidi_ops snd_mpu401_uart_input =
492 {
493 	.open =		snd_mpu401_uart_input_open,
494 	.close =	snd_mpu401_uart_input_close,
495 	.trigger =	snd_mpu401_uart_input_trigger,
496 };
497 
498 static void snd_mpu401_uart_free(struct snd_rawmidi *rmidi)
499 {
500 	struct snd_mpu401 *mpu = rmidi->private_data;
501 	if (mpu->irq >= 0)
502 		free_irq(mpu->irq, (void *) mpu);
503 	release_and_free_resource(mpu->res);
504 	kfree(mpu);
505 }
506 
507 /**
508  * snd_mpu401_uart_new - create an MPU401-UART instance
509  * @card: the card instance
510  * @device: the device index, zero-based
511  * @hardware: the hardware type, MPU401_HW_XXXX
512  * @port: the base address of MPU401 port
513  * @info_flags: bitflags MPU401_INFO_XXX
514  * @irq: the ISA irq number, -1 if not to be allocated
515  * @rrawmidi: the pointer to store the new rawmidi instance
516  *
517  * Creates a new MPU-401 instance.
518  *
519  * Note that the rawmidi instance is returned on the rrawmidi argument,
520  * not the mpu401 instance itself.  To access to the mpu401 instance,
521  * cast from rawmidi->private_data (with struct snd_mpu401 magic-cast).
522  *
523  * Return: Zero if successful, or a negative error code.
524  */
525 int snd_mpu401_uart_new(struct snd_card *card, int device,
526 			unsigned short hardware,
527 			unsigned long port,
528 			unsigned int info_flags,
529 			int irq,
530 			struct snd_rawmidi ** rrawmidi)
531 {
532 	struct snd_mpu401 *mpu;
533 	struct snd_rawmidi *rmidi;
534 	int in_enable, out_enable;
535 	int err;
536 
537 	if (rrawmidi)
538 		*rrawmidi = NULL;
539 	if (! (info_flags & (MPU401_INFO_INPUT | MPU401_INFO_OUTPUT)))
540 		info_flags |= MPU401_INFO_INPUT | MPU401_INFO_OUTPUT;
541 	in_enable = (info_flags & MPU401_INFO_INPUT) ? 1 : 0;
542 	out_enable = (info_flags & MPU401_INFO_OUTPUT) ? 1 : 0;
543 	if ((err = snd_rawmidi_new(card, "MPU-401U", device,
544 				   out_enable, in_enable, &rmidi)) < 0)
545 		return err;
546 	mpu = kzalloc(sizeof(*mpu), GFP_KERNEL);
547 	if (mpu == NULL) {
548 		snd_printk(KERN_ERR "mpu401_uart: cannot allocate\n");
549 		snd_device_free(card, rmidi);
550 		return -ENOMEM;
551 	}
552 	rmidi->private_data = mpu;
553 	rmidi->private_free = snd_mpu401_uart_free;
554 	spin_lock_init(&mpu->input_lock);
555 	spin_lock_init(&mpu->output_lock);
556 	spin_lock_init(&mpu->timer_lock);
557 	mpu->hardware = hardware;
558 	mpu->irq = -1;
559 	if (! (info_flags & MPU401_INFO_INTEGRATED)) {
560 		int res_size = hardware == MPU401_HW_PC98II ? 4 : 2;
561 		mpu->res = request_region(port, res_size, "MPU401 UART");
562 		if (mpu->res == NULL) {
563 			snd_printk(KERN_ERR "mpu401_uart: "
564 				   "unable to grab port 0x%lx size %d\n",
565 				   port, res_size);
566 			snd_device_free(card, rmidi);
567 			return -EBUSY;
568 		}
569 	}
570 	if (info_flags & MPU401_INFO_MMIO) {
571 		mpu->write = mpu401_write_mmio;
572 		mpu->read = mpu401_read_mmio;
573 	} else {
574 		mpu->write = mpu401_write_port;
575 		mpu->read = mpu401_read_port;
576 	}
577 	mpu->port = port;
578 	if (hardware == MPU401_HW_PC98II)
579 		mpu->cport = port + 2;
580 	else
581 		mpu->cport = port + 1;
582 	if (irq >= 0) {
583 		if (request_irq(irq, snd_mpu401_uart_interrupt, 0,
584 				"MPU401 UART", (void *) mpu)) {
585 			snd_printk(KERN_ERR "mpu401_uart: "
586 				   "unable to grab IRQ %d\n", irq);
587 			snd_device_free(card, rmidi);
588 			return -EBUSY;
589 		}
590 	}
591 	if (irq < 0 && !(info_flags & MPU401_INFO_IRQ_HOOK))
592 		info_flags |= MPU401_INFO_USE_TIMER;
593 	mpu->info_flags = info_flags;
594 	mpu->irq = irq;
595 	if (card->shortname[0])
596 		snprintf(rmidi->name, sizeof(rmidi->name), "%s MIDI",
597 			 card->shortname);
598 	else
599 		sprintf(rmidi->name, "MPU-401 MIDI %d-%d",card->number, device);
600 	if (out_enable) {
601 		snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_OUTPUT,
602 				    &snd_mpu401_uart_output);
603 		rmidi->info_flags |= SNDRV_RAWMIDI_INFO_OUTPUT;
604 	}
605 	if (in_enable) {
606 		snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_INPUT,
607 				    &snd_mpu401_uart_input);
608 		rmidi->info_flags |= SNDRV_RAWMIDI_INFO_INPUT;
609 		if (out_enable)
610 			rmidi->info_flags |= SNDRV_RAWMIDI_INFO_DUPLEX;
611 	}
612 	mpu->rmidi = rmidi;
613 	if (rrawmidi)
614 		*rrawmidi = rmidi;
615 	return 0;
616 }
617 
618 EXPORT_SYMBOL(snd_mpu401_uart_new);
619 
620 /*
621  *  INIT part
622  */
623 
624 static int __init alsa_mpu401_uart_init(void)
625 {
626 	return 0;
627 }
628 
629 static void __exit alsa_mpu401_uart_exit(void)
630 {
631 }
632 
633 module_init(alsa_mpu401_uart_init)
634 module_exit(alsa_mpu401_uart_exit)
635