1/*
2 * sound/oss/pas2_midi.c
3 *
4 * The low level driver for the PAS Midi Interface.
5 */
6/*
7 * Copyright (C) by Hannu Savolainen 1993-1997
8 *
9 * OSS/Free for Linux is distributed under the GNU GENERAL PUBLIC LICENSE (GPL)
10 * Version 2 (June 1991). See the "COPYING" file distributed with this software
11 * for more info.
12 *
13 * Bartlomiej Zolnierkiewicz	: Added __init to pas_init_mixer()
14 */
15
16#include <linux/init.h>
17#include <linux/spinlock.h>
18#include "sound_config.h"
19
20#include "pas2.h"
21
22extern spinlock_t pas_lock;
23
24static int      midi_busy, input_opened;
25static int      my_dev;
26
27int pas2_mididev=-1;
28
29static unsigned char tmp_queue[256];
30static volatile int qlen;
31static volatile unsigned char qhead, qtail;
32
33static void     (*midi_input_intr) (int dev, unsigned char data);
34
35static int pas_midi_open(int dev, int mode,
36	      void            (*input) (int dev, unsigned char data),
37	      void            (*output) (int dev)
38)
39{
40	int             err;
41	unsigned long   flags;
42	unsigned char   ctrl;
43
44
45	if (midi_busy)
46		return -EBUSY;
47
48	/*
49	 * Reset input and output FIFO pointers
50	 */
51	pas_write(0x20 | 0x40,
52		  0x178b);
53
54	spin_lock_irqsave(&pas_lock, flags);
55
56	if ((err = pas_set_intr(0x10)) < 0)
57	{
58		spin_unlock_irqrestore(&pas_lock, flags);
59		return err;
60	}
61	/*
62	 * Enable input available and output FIFO empty interrupts
63	 */
64
65	ctrl = 0;
66	input_opened = 0;
67	midi_input_intr = input;
68
69	if (mode == OPEN_READ || mode == OPEN_READWRITE)
70	{
71		ctrl |= 0x04;	/* Enable input */
72		input_opened = 1;
73	}
74	if (mode == OPEN_WRITE || mode == OPEN_READWRITE)
75	{
76		ctrl |= 0x08 | 0x10;	/* Enable output */
77	}
78	pas_write(ctrl, 0x178b);
79
80	/*
81	 * Acknowledge any pending interrupts
82	 */
83
84	pas_write(0xff, 0x1B88);
85
86	spin_unlock_irqrestore(&pas_lock, flags);
87
88	midi_busy = 1;
89	qlen = qhead = qtail = 0;
90	return 0;
91}
92
93static void pas_midi_close(int dev)
94{
95
96	/*
97	 * Reset FIFO pointers, disable intrs
98	 */
99	pas_write(0x20 | 0x40, 0x178b);
100
101	pas_remove_intr(0x10);
102	midi_busy = 0;
103}
104
105static int dump_to_midi(unsigned char midi_byte)
106{
107	int fifo_space, x;
108
109	fifo_space = ((x = pas_read(0x1B89)) >> 4) & 0x0f;
110
111	/*
112	 * The MIDI FIFO space register and it's documentation is nonunderstandable.
113	 * There seem to be no way to differentiate between buffer full and buffer
114	 * empty situations. For this reason we don't never write the buffer
115	 * completely full. In this way we can assume that 0 (or is it 15)
116	 * means that the buffer is empty.
117	 */
118
119	if (fifo_space < 2 && fifo_space != 0)	/* Full (almost) */
120		return 0;	/* Ask upper layers to retry after some time */
121
122	pas_write(midi_byte, 0x178A);
123
124	return 1;
125}
126
127static int pas_midi_out(int dev, unsigned char midi_byte)
128{
129
130	unsigned long flags;
131
132	/*
133	 * Drain the local queue first
134	 */
135
136	spin_lock_irqsave(&pas_lock, flags);
137
138	while (qlen && dump_to_midi(tmp_queue[qhead]))
139	{
140		qlen--;
141		qhead++;
142	}
143
144	spin_unlock_irqrestore(&pas_lock, flags);
145
146	/*
147	 *	Output the byte if the local queue is empty.
148	 */
149
150	if (!qlen)
151		if (dump_to_midi(midi_byte))
152			return 1;
153
154	/*
155	 *	Put to the local queue
156	 */
157
158	if (qlen >= 256)
159		return 0;	/* Local queue full */
160
161	spin_lock_irqsave(&pas_lock, flags);
162
163	tmp_queue[qtail] = midi_byte;
164	qlen++;
165	qtail++;
166
167	spin_unlock_irqrestore(&pas_lock, flags);
168
169	return 1;
170}
171
172static int pas_midi_start_read(int dev)
173{
174	return 0;
175}
176
177static int pas_midi_end_read(int dev)
178{
179	return 0;
180}
181
182static void pas_midi_kick(int dev)
183{
184}
185
186static int pas_buffer_status(int dev)
187{
188	return qlen;
189}
190
191#define MIDI_SYNTH_NAME	"Pro Audio Spectrum Midi"
192#define MIDI_SYNTH_CAPS	SYNTH_CAP_INPUT
193#include "midi_synth.h"
194
195static struct midi_operations pas_midi_operations =
196{
197	.owner		= THIS_MODULE,
198	.info		= {"Pro Audio Spectrum", 0, 0, SNDCARD_PAS},
199	.converter	= &std_midi_synth,
200	.in_info	= {0},
201	.open		= pas_midi_open,
202	.close		= pas_midi_close,
203	.outputc	= pas_midi_out,
204	.start_read	= pas_midi_start_read,
205	.end_read	= pas_midi_end_read,
206	.kick		= pas_midi_kick,
207	.buffer_status	= pas_buffer_status,
208};
209
210void __init pas_midi_init(void)
211{
212	int dev = sound_alloc_mididev();
213
214	if (dev == -1)
215	{
216		printk(KERN_WARNING "pas_midi_init: Too many midi devices detected\n");
217		return;
218	}
219	std_midi_synth.midi_dev = my_dev = dev;
220	midi_devs[dev] = &pas_midi_operations;
221	pas2_mididev = dev;
222	sequencer_init();
223}
224
225void pas_midi_interrupt(void)
226{
227	unsigned char   stat;
228	int             i, incount;
229
230	stat = pas_read(0x1B88);
231
232	if (stat & 0x04)	/* Input data available */
233	{
234		incount = pas_read(0x1B89) & 0x0f;	/* Input FIFO size */
235		if (!incount)
236			incount = 16;
237
238		for (i = 0; i < incount; i++)
239			if (input_opened)
240			{
241				midi_input_intr(my_dev, pas_read(0x178A));
242			} else
243				pas_read(0x178A);	/* Flush */
244	}
245	if (stat & (0x08 | 0x10))
246	{
247		spin_lock(&pas_lock);/* called in irq context */
248
249		while (qlen && dump_to_midi(tmp_queue[qhead]))
250		{
251			qlen--;
252			qhead++;
253		}
254
255		spin_unlock(&pas_lock);
256	}
257	if (stat & 0x40)
258	{
259		printk(KERN_WARNING "MIDI output overrun %x,%x\n", pas_read(0x1B89), stat);
260	}
261	pas_write(stat, 0x1B88);	/* Acknowledge interrupts */
262}
263