1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
4 *  Copyright (c) 2009 by Krzysztof Helt
5 *  Routines for control of MPU-401 in UART mode
6 *
7 *  MPU-401 supports UART mode which is not capable generate transmit
8 *  interrupts thus output is done via polling. Also, if irq < 0, then
9 *  input is done also via polling. Do not expect good performance.
10 */
11
12#include <linux/io.h>
13#include <linux/slab.h>
14#include <linux/delay.h>
15#include <linux/ioport.h>
16#include <linux/errno.h>
17#include <linux/export.h>
18#include <sound/core.h>
19#include <sound/rawmidi.h>
20
21#include "msnd.h"
22
23#define MSNDMIDI_MODE_BIT_INPUT		0
24#define MSNDMIDI_MODE_BIT_OUTPUT		1
25#define MSNDMIDI_MODE_BIT_INPUT_TRIGGER	2
26#define MSNDMIDI_MODE_BIT_OUTPUT_TRIGGER	3
27
28struct snd_msndmidi {
29	struct snd_msnd *dev;
30
31	unsigned long mode;		/* MSNDMIDI_MODE_XXXX */
32
33	struct snd_rawmidi_substream *substream_input;
34
35	spinlock_t input_lock;
36};
37
38/*
39 * input/output open/close - protected by open_mutex in rawmidi.c
40 */
41static int snd_msndmidi_input_open(struct snd_rawmidi_substream *substream)
42{
43	struct snd_msndmidi *mpu;
44
45	snd_printdd("snd_msndmidi_input_open()\n");
46
47	mpu = substream->rmidi->private_data;
48
49	mpu->substream_input = substream;
50
51	snd_msnd_enable_irq(mpu->dev);
52
53	snd_msnd_send_dsp_cmd(mpu->dev, HDEX_MIDI_IN_START);
54	set_bit(MSNDMIDI_MODE_BIT_INPUT, &mpu->mode);
55	return 0;
56}
57
58static int snd_msndmidi_input_close(struct snd_rawmidi_substream *substream)
59{
60	struct snd_msndmidi *mpu;
61
62	mpu = substream->rmidi->private_data;
63	snd_msnd_send_dsp_cmd(mpu->dev, HDEX_MIDI_IN_STOP);
64	clear_bit(MSNDMIDI_MODE_BIT_INPUT, &mpu->mode);
65	mpu->substream_input = NULL;
66	snd_msnd_disable_irq(mpu->dev);
67	return 0;
68}
69
70static void snd_msndmidi_input_drop(struct snd_msndmidi *mpu)
71{
72	u16 tail;
73
74	tail = readw(mpu->dev->MIDQ + JQS_wTail);
75	writew(tail, mpu->dev->MIDQ + JQS_wHead);
76}
77
78/*
79 * trigger input
80 */
81static void snd_msndmidi_input_trigger(struct snd_rawmidi_substream *substream,
82					int up)
83{
84	unsigned long flags;
85	struct snd_msndmidi *mpu;
86
87	snd_printdd("snd_msndmidi_input_trigger(, %i)\n", up);
88
89	mpu = substream->rmidi->private_data;
90	spin_lock_irqsave(&mpu->input_lock, flags);
91	if (up) {
92		if (!test_and_set_bit(MSNDMIDI_MODE_BIT_INPUT_TRIGGER,
93				      &mpu->mode))
94			snd_msndmidi_input_drop(mpu);
95	} else {
96		clear_bit(MSNDMIDI_MODE_BIT_INPUT_TRIGGER, &mpu->mode);
97	}
98	spin_unlock_irqrestore(&mpu->input_lock, flags);
99	if (up)
100		snd_msndmidi_input_read(mpu);
101}
102
103void snd_msndmidi_input_read(void *mpuv)
104{
105	unsigned long flags;
106	struct snd_msndmidi *mpu = mpuv;
107	void __iomem *pwMIDQData = mpu->dev->mappedbase + MIDQ_DATA_BUFF;
108	u16 head, tail, size;
109
110	spin_lock_irqsave(&mpu->input_lock, flags);
111	head = readw(mpu->dev->MIDQ + JQS_wHead);
112	tail = readw(mpu->dev->MIDQ + JQS_wTail);
113	size = readw(mpu->dev->MIDQ + JQS_wSize);
114	if (head > size || tail > size)
115		goto out;
116	while (head != tail) {
117		unsigned char val = readw(pwMIDQData + 2 * head);
118
119		if (test_bit(MSNDMIDI_MODE_BIT_INPUT_TRIGGER, &mpu->mode))
120			snd_rawmidi_receive(mpu->substream_input, &val, 1);
121		if (++head > size)
122			head = 0;
123		writew(head, mpu->dev->MIDQ + JQS_wHead);
124	}
125 out:
126	spin_unlock_irqrestore(&mpu->input_lock, flags);
127}
128EXPORT_SYMBOL(snd_msndmidi_input_read);
129
130static const struct snd_rawmidi_ops snd_msndmidi_input = {
131	.open =		snd_msndmidi_input_open,
132	.close =	snd_msndmidi_input_close,
133	.trigger =	snd_msndmidi_input_trigger,
134};
135
136static void snd_msndmidi_free(struct snd_rawmidi *rmidi)
137{
138	struct snd_msndmidi *mpu = rmidi->private_data;
139	kfree(mpu);
140}
141
142int snd_msndmidi_new(struct snd_card *card, int device)
143{
144	struct snd_msnd *chip = card->private_data;
145	struct snd_msndmidi *mpu;
146	struct snd_rawmidi *rmidi;
147	int err;
148
149	err = snd_rawmidi_new(card, "MSND-MIDI", device, 1, 1, &rmidi);
150	if (err < 0)
151		return err;
152	mpu = kzalloc(sizeof(*mpu), GFP_KERNEL);
153	if (mpu == NULL) {
154		snd_device_free(card, rmidi);
155		return -ENOMEM;
156	}
157	mpu->dev = chip;
158	chip->msndmidi_mpu = mpu;
159	rmidi->private_data = mpu;
160	rmidi->private_free = snd_msndmidi_free;
161	spin_lock_init(&mpu->input_lock);
162	strcpy(rmidi->name, "MSND MIDI");
163	snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_INPUT,
164			    &snd_msndmidi_input);
165	rmidi->info_flags |= SNDRV_RAWMIDI_INFO_INPUT;
166	return 0;
167}
168