1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
4 *  Routines for control of MPU-401 in UART mode
5 *
6 *  MPU-401 supports UART mode which is not capable generate transmit
7 *  interrupts thus output is done via polling. Without interrupt,
8 *  input is done also via polling. Do not expect good performance.
9 *
10 *   13-03-2003:
11 *      Added support for different kind of hardware I/O. Build in choices
12 *      are port and mmio. For other kind of I/O, set mpu->read and
13 *      mpu->write to your own I/O functions.
14 */
15
16#include <linux/io.h>
17#include <linux/delay.h>
18#include <linux/init.h>
19#include <linux/slab.h>
20#include <linux/ioport.h>
21#include <linux/module.h>
22#include <linux/interrupt.h>
23#include <linux/errno.h>
24#include <sound/core.h>
25#include <sound/mpu401.h>
26
27MODULE_AUTHOR("Jaroslav Kysela <perex@perex.cz>");
28MODULE_DESCRIPTION("Routines for control of MPU-401 in UART mode");
29MODULE_LICENSE("GPL");
30
31static void snd_mpu401_uart_input_read(struct snd_mpu401 * mpu);
32static void snd_mpu401_uart_output_write(struct snd_mpu401 * mpu);
33
34/*
35
36 */
37
38#define snd_mpu401_input_avail(mpu) \
39	(!(mpu->read(mpu, MPU401C(mpu)) & MPU401_RX_EMPTY))
40#define snd_mpu401_output_ready(mpu) \
41	(!(mpu->read(mpu, MPU401C(mpu)) & MPU401_TX_FULL))
42
43/* Build in lowlevel io */
44static void mpu401_write_port(struct snd_mpu401 *mpu, unsigned char data,
45			      unsigned long addr)
46{
47	outb(data, addr);
48}
49
50static unsigned char mpu401_read_port(struct snd_mpu401 *mpu,
51				      unsigned long addr)
52{
53	return inb(addr);
54}
55
56static void mpu401_write_mmio(struct snd_mpu401 *mpu, unsigned char data,
57			      unsigned long addr)
58{
59	writeb(data, (void __iomem *)addr);
60}
61
62static unsigned char mpu401_read_mmio(struct snd_mpu401 *mpu,
63				      unsigned long addr)
64{
65	return readb((void __iomem *)addr);
66}
67/*  */
68
69static void snd_mpu401_uart_clear_rx(struct snd_mpu401 *mpu)
70{
71	int timeout = 100000;
72	for (; timeout > 0 && snd_mpu401_input_avail(mpu); timeout--)
73		mpu->read(mpu, MPU401D(mpu));
74#ifdef CONFIG_SND_DEBUG
75	if (timeout <= 0)
76		snd_printk(KERN_ERR "cmd: clear rx timeout (status = 0x%x)\n",
77			   mpu->read(mpu, MPU401C(mpu)));
78#endif
79}
80
81static void uart_interrupt_tx(struct snd_mpu401 *mpu)
82{
83	unsigned long flags;
84
85	if (test_bit(MPU401_MODE_BIT_OUTPUT, &mpu->mode) &&
86	    test_bit(MPU401_MODE_BIT_OUTPUT_TRIGGER, &mpu->mode)) {
87		spin_lock_irqsave(&mpu->output_lock, flags);
88		snd_mpu401_uart_output_write(mpu);
89		spin_unlock_irqrestore(&mpu->output_lock, flags);
90	}
91}
92
93static void _snd_mpu401_uart_interrupt(struct snd_mpu401 *mpu)
94{
95	unsigned long flags;
96
97	if (mpu->info_flags & MPU401_INFO_INPUT) {
98		spin_lock_irqsave(&mpu->input_lock, flags);
99		if (test_bit(MPU401_MODE_BIT_INPUT, &mpu->mode))
100			snd_mpu401_uart_input_read(mpu);
101		else
102			snd_mpu401_uart_clear_rx(mpu);
103		spin_unlock_irqrestore(&mpu->input_lock, flags);
104	}
105	if (! (mpu->info_flags & MPU401_INFO_TX_IRQ))
106		/* ok. for better Tx performance try do some output
107		   when input is done */
108		uart_interrupt_tx(mpu);
109}
110
111/**
112 * snd_mpu401_uart_interrupt - generic MPU401-UART interrupt handler
113 * @irq: the irq number
114 * @dev_id: mpu401 instance
115 *
116 * Processes the interrupt for MPU401-UART i/o.
117 *
118 * Return: %IRQ_HANDLED if the interrupt was handled. %IRQ_NONE otherwise.
119 */
120irqreturn_t snd_mpu401_uart_interrupt(int irq, void *dev_id)
121{
122	struct snd_mpu401 *mpu = dev_id;
123
124	if (!mpu)
125		return IRQ_NONE;
126	_snd_mpu401_uart_interrupt(mpu);
127	return IRQ_HANDLED;
128}
129
130EXPORT_SYMBOL(snd_mpu401_uart_interrupt);
131
132/**
133 * snd_mpu401_uart_interrupt_tx - generic MPU401-UART transmit irq handler
134 * @irq: the irq number
135 * @dev_id: mpu401 instance
136 *
137 * Processes the interrupt for MPU401-UART output.
138 *
139 * Return: %IRQ_HANDLED if the interrupt was handled. %IRQ_NONE otherwise.
140 */
141irqreturn_t snd_mpu401_uart_interrupt_tx(int irq, void *dev_id)
142{
143	struct snd_mpu401 *mpu = dev_id;
144
145	if (!mpu)
146		return IRQ_NONE;
147	uart_interrupt_tx(mpu);
148	return IRQ_HANDLED;
149}
150
151EXPORT_SYMBOL(snd_mpu401_uart_interrupt_tx);
152
153/*
154 * timer callback
155 * reprogram the timer and call the interrupt job
156 */
157static void snd_mpu401_uart_timer(struct timer_list *t)
158{
159	struct snd_mpu401 *mpu = from_timer(mpu, t, timer);
160	unsigned long flags;
161
162	spin_lock_irqsave(&mpu->timer_lock, flags);
163	/*mpu->mode |= MPU401_MODE_TIMER;*/
164	mod_timer(&mpu->timer,  1 + jiffies);
165	spin_unlock_irqrestore(&mpu->timer_lock, flags);
166	if (mpu->rmidi)
167		_snd_mpu401_uart_interrupt(mpu);
168}
169
170/*
171 * initialize the timer callback if not programmed yet
172 */
173static void snd_mpu401_uart_add_timer (struct snd_mpu401 *mpu, int input)
174{
175	unsigned long flags;
176
177	spin_lock_irqsave (&mpu->timer_lock, flags);
178	if (mpu->timer_invoked == 0) {
179		timer_setup(&mpu->timer, snd_mpu401_uart_timer, 0);
180		mod_timer(&mpu->timer, 1 + jiffies);
181	}
182	mpu->timer_invoked |= input ? MPU401_MODE_INPUT_TIMER :
183		MPU401_MODE_OUTPUT_TIMER;
184	spin_unlock_irqrestore (&mpu->timer_lock, flags);
185}
186
187/*
188 * remove the timer callback if still active
189 */
190static void snd_mpu401_uart_remove_timer (struct snd_mpu401 *mpu, int input)
191{
192	unsigned long flags;
193
194	spin_lock_irqsave (&mpu->timer_lock, flags);
195	if (mpu->timer_invoked) {
196		mpu->timer_invoked &= input ? ~MPU401_MODE_INPUT_TIMER :
197			~MPU401_MODE_OUTPUT_TIMER;
198		if (! mpu->timer_invoked)
199			del_timer(&mpu->timer);
200	}
201	spin_unlock_irqrestore (&mpu->timer_lock, flags);
202}
203
204/*
205 * send a UART command
206 * return zero if successful, non-zero for some errors
207 */
208
209static int snd_mpu401_uart_cmd(struct snd_mpu401 * mpu, unsigned char cmd,
210			       int ack)
211{
212	unsigned long flags;
213	int timeout, ok;
214
215	spin_lock_irqsave(&mpu->input_lock, flags);
216	if (mpu->hardware != MPU401_HW_TRID4DWAVE) {
217		mpu->write(mpu, 0x00, MPU401D(mpu));
218		/*snd_mpu401_uart_clear_rx(mpu);*/
219	}
220	/* ok. standard MPU-401 initialization */
221	if (mpu->hardware != MPU401_HW_SB) {
222		for (timeout = 1000; timeout > 0 &&
223			     !snd_mpu401_output_ready(mpu); timeout--)
224			udelay(10);
225#ifdef CONFIG_SND_DEBUG
226		if (!timeout)
227			snd_printk(KERN_ERR "cmd: tx timeout (status = 0x%x)\n",
228				   mpu->read(mpu, MPU401C(mpu)));
229#endif
230	}
231	mpu->write(mpu, cmd, MPU401C(mpu));
232	if (ack && !(mpu->info_flags & MPU401_INFO_NO_ACK)) {
233		ok = 0;
234		timeout = 10000;
235		while (!ok && timeout-- > 0) {
236			if (snd_mpu401_input_avail(mpu)) {
237				if (mpu->read(mpu, MPU401D(mpu)) == MPU401_ACK)
238					ok = 1;
239			}
240		}
241		if (!ok && mpu->read(mpu, MPU401D(mpu)) == MPU401_ACK)
242			ok = 1;
243	} else
244		ok = 1;
245	spin_unlock_irqrestore(&mpu->input_lock, flags);
246	if (!ok) {
247		snd_printk(KERN_ERR "cmd: 0x%x failed at 0x%lx "
248			   "(status = 0x%x, data = 0x%x)\n", cmd, mpu->port,
249			   mpu->read(mpu, MPU401C(mpu)),
250			   mpu->read(mpu, MPU401D(mpu)));
251		return 1;
252	}
253	return 0;
254}
255
256static int snd_mpu401_do_reset(struct snd_mpu401 *mpu)
257{
258	if (snd_mpu401_uart_cmd(mpu, MPU401_RESET, 1))
259		return -EIO;
260	if (snd_mpu401_uart_cmd(mpu, MPU401_ENTER_UART, 0))
261		return -EIO;
262	return 0;
263}
264
265/*
266 * input/output open/close - protected by open_mutex in rawmidi.c
267 */
268static int snd_mpu401_uart_input_open(struct snd_rawmidi_substream *substream)
269{
270	struct snd_mpu401 *mpu;
271	int err;
272
273	mpu = substream->rmidi->private_data;
274	if (mpu->open_input && (err = mpu->open_input(mpu)) < 0)
275		return err;
276	if (! test_bit(MPU401_MODE_BIT_OUTPUT, &mpu->mode)) {
277		if (snd_mpu401_do_reset(mpu) < 0)
278			goto error_out;
279	}
280	mpu->substream_input = substream;
281	set_bit(MPU401_MODE_BIT_INPUT, &mpu->mode);
282	return 0;
283
284error_out:
285	if (mpu->open_input && mpu->close_input)
286		mpu->close_input(mpu);
287	return -EIO;
288}
289
290static int snd_mpu401_uart_output_open(struct snd_rawmidi_substream *substream)
291{
292	struct snd_mpu401 *mpu;
293	int err;
294
295	mpu = substream->rmidi->private_data;
296	if (mpu->open_output && (err = mpu->open_output(mpu)) < 0)
297		return err;
298	if (! test_bit(MPU401_MODE_BIT_INPUT, &mpu->mode)) {
299		if (snd_mpu401_do_reset(mpu) < 0)
300			goto error_out;
301	}
302	mpu->substream_output = substream;
303	set_bit(MPU401_MODE_BIT_OUTPUT, &mpu->mode);
304	return 0;
305
306error_out:
307	if (mpu->open_output && mpu->close_output)
308		mpu->close_output(mpu);
309	return -EIO;
310}
311
312static int snd_mpu401_uart_input_close(struct snd_rawmidi_substream *substream)
313{
314	struct snd_mpu401 *mpu;
315	int err = 0;
316
317	mpu = substream->rmidi->private_data;
318	clear_bit(MPU401_MODE_BIT_INPUT, &mpu->mode);
319	mpu->substream_input = NULL;
320	if (! test_bit(MPU401_MODE_BIT_OUTPUT, &mpu->mode))
321		err = snd_mpu401_uart_cmd(mpu, MPU401_RESET, 0);
322	if (mpu->close_input)
323		mpu->close_input(mpu);
324	if (err)
325		return -EIO;
326	return 0;
327}
328
329static int snd_mpu401_uart_output_close(struct snd_rawmidi_substream *substream)
330{
331	struct snd_mpu401 *mpu;
332	int err = 0;
333
334	mpu = substream->rmidi->private_data;
335	clear_bit(MPU401_MODE_BIT_OUTPUT, &mpu->mode);
336	mpu->substream_output = NULL;
337	if (! test_bit(MPU401_MODE_BIT_INPUT, &mpu->mode))
338		err = snd_mpu401_uart_cmd(mpu, MPU401_RESET, 0);
339	if (mpu->close_output)
340		mpu->close_output(mpu);
341	if (err)
342		return -EIO;
343	return 0;
344}
345
346/*
347 * trigger input callback
348 */
349static void
350snd_mpu401_uart_input_trigger(struct snd_rawmidi_substream *substream, int up)
351{
352	unsigned long flags;
353	struct snd_mpu401 *mpu;
354	int max = 64;
355
356	mpu = substream->rmidi->private_data;
357	if (up) {
358		if (! test_and_set_bit(MPU401_MODE_BIT_INPUT_TRIGGER,
359				       &mpu->mode)) {
360			/* first time - flush FIFO */
361			while (max-- > 0)
362				mpu->read(mpu, MPU401D(mpu));
363			if (mpu->info_flags & MPU401_INFO_USE_TIMER)
364				snd_mpu401_uart_add_timer(mpu, 1);
365		}
366
367		/* read data in advance */
368		spin_lock_irqsave(&mpu->input_lock, flags);
369		snd_mpu401_uart_input_read(mpu);
370		spin_unlock_irqrestore(&mpu->input_lock, flags);
371	} else {
372		if (mpu->info_flags & MPU401_INFO_USE_TIMER)
373			snd_mpu401_uart_remove_timer(mpu, 1);
374		clear_bit(MPU401_MODE_BIT_INPUT_TRIGGER, &mpu->mode);
375	}
376
377}
378
379/*
380 * transfer input pending data
381 * call with input_lock spinlock held
382 */
383static void snd_mpu401_uart_input_read(struct snd_mpu401 * mpu)
384{
385	int max = 128;
386	unsigned char byte;
387
388	while (max-- > 0) {
389		if (! snd_mpu401_input_avail(mpu))
390			break; /* input not available */
391		byte = mpu->read(mpu, MPU401D(mpu));
392		if (test_bit(MPU401_MODE_BIT_INPUT_TRIGGER, &mpu->mode))
393			snd_rawmidi_receive(mpu->substream_input, &byte, 1);
394	}
395}
396
397/*
398 *  Tx FIFO sizes:
399 *    CS4237B			- 16 bytes
400 *    AudioDrive ES1688         - 12 bytes
401 *    S3 SonicVibes             -  8 bytes
402 *    SoundBlaster AWE 64       -  2 bytes (ugly hardware)
403 */
404
405/*
406 * write output pending bytes
407 * call with output_lock spinlock held
408 */
409static void snd_mpu401_uart_output_write(struct snd_mpu401 * mpu)
410{
411	unsigned char byte;
412	int max = 256;
413
414	do {
415		if (snd_rawmidi_transmit_peek(mpu->substream_output,
416					      &byte, 1) == 1) {
417			/*
418			 * Try twice because there is hardware that insists on
419			 * setting the output busy bit after each write.
420			 */
421			if (!snd_mpu401_output_ready(mpu) &&
422			    !snd_mpu401_output_ready(mpu))
423				break;	/* Tx FIFO full - try again later */
424			mpu->write(mpu, byte, MPU401D(mpu));
425			snd_rawmidi_transmit_ack(mpu->substream_output, 1);
426		} else {
427			snd_mpu401_uart_remove_timer (mpu, 0);
428			break;	/* no other data - leave the tx loop */
429		}
430	} while (--max > 0);
431}
432
433/*
434 * output trigger callback
435 */
436static void
437snd_mpu401_uart_output_trigger(struct snd_rawmidi_substream *substream, int up)
438{
439	unsigned long flags;
440	struct snd_mpu401 *mpu;
441
442	mpu = substream->rmidi->private_data;
443	if (up) {
444		set_bit(MPU401_MODE_BIT_OUTPUT_TRIGGER, &mpu->mode);
445
446		/* try to add the timer at each output trigger,
447		 * since the output timer might have been removed in
448		 * snd_mpu401_uart_output_write().
449		 */
450		if (! (mpu->info_flags & MPU401_INFO_TX_IRQ))
451			snd_mpu401_uart_add_timer(mpu, 0);
452
453		/* output pending data */
454		spin_lock_irqsave(&mpu->output_lock, flags);
455		snd_mpu401_uart_output_write(mpu);
456		spin_unlock_irqrestore(&mpu->output_lock, flags);
457	} else {
458		if (! (mpu->info_flags & MPU401_INFO_TX_IRQ))
459			snd_mpu401_uart_remove_timer(mpu, 0);
460		clear_bit(MPU401_MODE_BIT_OUTPUT_TRIGGER, &mpu->mode);
461	}
462}
463
464/*
465
466 */
467
468static const struct snd_rawmidi_ops snd_mpu401_uart_output =
469{
470	.open =		snd_mpu401_uart_output_open,
471	.close =	snd_mpu401_uart_output_close,
472	.trigger =	snd_mpu401_uart_output_trigger,
473};
474
475static const struct snd_rawmidi_ops snd_mpu401_uart_input =
476{
477	.open =		snd_mpu401_uart_input_open,
478	.close =	snd_mpu401_uart_input_close,
479	.trigger =	snd_mpu401_uart_input_trigger,
480};
481
482static void snd_mpu401_uart_free(struct snd_rawmidi *rmidi)
483{
484	struct snd_mpu401 *mpu = rmidi->private_data;
485	if (mpu->irq >= 0)
486		free_irq(mpu->irq, (void *) mpu);
487	release_and_free_resource(mpu->res);
488	kfree(mpu);
489}
490
491/**
492 * snd_mpu401_uart_new - create an MPU401-UART instance
493 * @card: the card instance
494 * @device: the device index, zero-based
495 * @hardware: the hardware type, MPU401_HW_XXXX
496 * @port: the base address of MPU401 port
497 * @info_flags: bitflags MPU401_INFO_XXX
498 * @irq: the ISA irq number, -1 if not to be allocated
499 * @rrawmidi: the pointer to store the new rawmidi instance
500 *
501 * Creates a new MPU-401 instance.
502 *
503 * Note that the rawmidi instance is returned on the rrawmidi argument,
504 * not the mpu401 instance itself.  To access to the mpu401 instance,
505 * cast from rawmidi->private_data (with struct snd_mpu401 magic-cast).
506 *
507 * Return: Zero if successful, or a negative error code.
508 */
509int snd_mpu401_uart_new(struct snd_card *card, int device,
510			unsigned short hardware,
511			unsigned long port,
512			unsigned int info_flags,
513			int irq,
514			struct snd_rawmidi ** rrawmidi)
515{
516	struct snd_mpu401 *mpu;
517	struct snd_rawmidi *rmidi;
518	int in_enable, out_enable;
519	int err;
520
521	if (rrawmidi)
522		*rrawmidi = NULL;
523	if (! (info_flags & (MPU401_INFO_INPUT | MPU401_INFO_OUTPUT)))
524		info_flags |= MPU401_INFO_INPUT | MPU401_INFO_OUTPUT;
525	in_enable = (info_flags & MPU401_INFO_INPUT) ? 1 : 0;
526	out_enable = (info_flags & MPU401_INFO_OUTPUT) ? 1 : 0;
527	if ((err = snd_rawmidi_new(card, "MPU-401U", device,
528				   out_enable, in_enable, &rmidi)) < 0)
529		return err;
530	mpu = kzalloc(sizeof(*mpu), GFP_KERNEL);
531	if (!mpu) {
532		err = -ENOMEM;
533		goto free_device;
534	}
535	rmidi->private_data = mpu;
536	rmidi->private_free = snd_mpu401_uart_free;
537	spin_lock_init(&mpu->input_lock);
538	spin_lock_init(&mpu->output_lock);
539	spin_lock_init(&mpu->timer_lock);
540	mpu->hardware = hardware;
541	mpu->irq = -1;
542	if (! (info_flags & MPU401_INFO_INTEGRATED)) {
543		int res_size = hardware == MPU401_HW_PC98II ? 4 : 2;
544		mpu->res = request_region(port, res_size, "MPU401 UART");
545		if (!mpu->res) {
546			snd_printk(KERN_ERR "mpu401_uart: "
547				   "unable to grab port 0x%lx size %d\n",
548				   port, res_size);
549			err = -EBUSY;
550			goto free_device;
551		}
552	}
553	if (info_flags & MPU401_INFO_MMIO) {
554		mpu->write = mpu401_write_mmio;
555		mpu->read = mpu401_read_mmio;
556	} else {
557		mpu->write = mpu401_write_port;
558		mpu->read = mpu401_read_port;
559	}
560	mpu->port = port;
561	if (hardware == MPU401_HW_PC98II)
562		mpu->cport = port + 2;
563	else
564		mpu->cport = port + 1;
565	if (irq >= 0) {
566		if (request_irq(irq, snd_mpu401_uart_interrupt, 0,
567				"MPU401 UART", (void *) mpu)) {
568			snd_printk(KERN_ERR "mpu401_uart: "
569				   "unable to grab IRQ %d\n", irq);
570			err = -EBUSY;
571			goto free_device;
572		}
573	}
574	if (irq < 0 && !(info_flags & MPU401_INFO_IRQ_HOOK))
575		info_flags |= MPU401_INFO_USE_TIMER;
576	mpu->info_flags = info_flags;
577	mpu->irq = irq;
578	if (card->shortname[0])
579		snprintf(rmidi->name, sizeof(rmidi->name), "%s MIDI",
580			 card->shortname);
581	else
582		sprintf(rmidi->name, "MPU-401 MIDI %d-%d",card->number, device);
583	if (out_enable) {
584		snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_OUTPUT,
585				    &snd_mpu401_uart_output);
586		rmidi->info_flags |= SNDRV_RAWMIDI_INFO_OUTPUT;
587	}
588	if (in_enable) {
589		snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_INPUT,
590				    &snd_mpu401_uart_input);
591		rmidi->info_flags |= SNDRV_RAWMIDI_INFO_INPUT;
592		if (out_enable)
593			rmidi->info_flags |= SNDRV_RAWMIDI_INFO_DUPLEX;
594	}
595	mpu->rmidi = rmidi;
596	if (rrawmidi)
597		*rrawmidi = rmidi;
598	return 0;
599free_device:
600	snd_device_free(card, rmidi);
601	return err;
602}
603
604EXPORT_SYMBOL(snd_mpu401_uart_new);
605