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seq_oss_readq.c
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1 /*
2  * OSS compatible sequencer driver
3  *
4  * seq_oss_readq.c - MIDI input queue
5  *
6  * Copyright (C) 1998,99 Takashi Iwai <[email protected]>
7  *
8  * This program is free software; you can redistribute it and/or modify
9  * it under the terms of the GNU General Public License as published by
10  * the Free Software Foundation; either version 2 of the License, or
11  * (at your option) any later version.
12  *
13  * This program is distributed in the hope that it will be useful,
14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16  * GNU General Public License for more details.
17  *
18  * You should have received a copy of the GNU General Public License
19  * along with this program; if not, write to the Free Software
20  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
21  */
22 
23 #include "seq_oss_readq.h"
24 #include "seq_oss_event.h"
25 #include <sound/seq_oss_legacy.h>
26 #include "../seq_lock.h"
27 #include <linux/wait.h>
28 #include <linux/slab.h>
29 
30 /*
31  * constants
32  */
33 //#define SNDRV_SEQ_OSS_MAX_TIMEOUT (unsigned long)(-1)
34 #define SNDRV_SEQ_OSS_MAX_TIMEOUT (HZ * 3600)
35 
36 
37 /*
38  * prototypes
39  */
40 
41 
42 /*
43  * create a read queue
44  */
45 struct seq_oss_readq *
47 {
48  struct seq_oss_readq *q;
49 
50  if ((q = kzalloc(sizeof(*q), GFP_KERNEL)) == NULL) {
51  snd_printk(KERN_ERR "can't malloc read queue\n");
52  return NULL;
53  }
54 
55  if ((q->q = kcalloc(maxlen, sizeof(union evrec), GFP_KERNEL)) == NULL) {
56  snd_printk(KERN_ERR "can't malloc read queue buffer\n");
57  kfree(q);
58  return NULL;
59  }
60 
61  q->maxlen = maxlen;
62  q->qlen = 0;
63  q->head = q->tail = 0;
65  spin_lock_init(&q->lock);
67  q->input_time = (unsigned long)-1;
68 
69  return q;
70 }
71 
72 /*
73  * delete the read queue
74  */
75 void
77 {
78  if (q) {
79  kfree(q->q);
80  kfree(q);
81  }
82 }
83 
84 /*
85  * reset the read queue
86  */
87 void
89 {
90  if (q->qlen) {
91  q->qlen = 0;
92  q->head = q->tail = 0;
93  }
94  /* if someone sleeping, wake'em up */
95  if (waitqueue_active(&q->midi_sleep))
96  wake_up(&q->midi_sleep);
97  q->input_time = (unsigned long)-1;
98 }
99 
100 /*
101  * put a midi byte
102  */
103 int
104 snd_seq_oss_readq_puts(struct seq_oss_readq *q, int dev, unsigned char *data, int len)
105 {
106  union evrec rec;
107  int result;
108 
109  memset(&rec, 0, sizeof(rec));
110  rec.c[0] = SEQ_MIDIPUTC;
111  rec.c[2] = dev;
112 
113  while (len-- > 0) {
114  rec.c[1] = *data++;
115  result = snd_seq_oss_readq_put_event(q, &rec);
116  if (result < 0)
117  return result;
118  }
119  return 0;
120 }
121 
122 /*
123  * copy an event to input queue:
124  * return zero if enqueued
125  */
126 int
128 {
129  unsigned long flags;
130 
131  spin_lock_irqsave(&q->lock, flags);
132  if (q->qlen >= q->maxlen - 1) {
133  spin_unlock_irqrestore(&q->lock, flags);
134  return -ENOMEM;
135  }
136 
137  memcpy(&q->q[q->tail], ev, sizeof(*ev));
138  q->tail = (q->tail + 1) % q->maxlen;
139  q->qlen++;
140 
141  /* wake up sleeper */
142  if (waitqueue_active(&q->midi_sleep))
143  wake_up(&q->midi_sleep);
144 
145  spin_unlock_irqrestore(&q->lock, flags);
146 
147  return 0;
148 }
149 
150 
151 /*
152  * pop queue
153  * caller must hold lock
154  */
155 int
157 {
158  if (q->qlen == 0)
159  return -EAGAIN;
160  memcpy(rec, &q->q[q->head], sizeof(*rec));
161  return 0;
162 }
163 
164 /*
165  * sleep until ready
166  */
167 void
169 {
171  (q->qlen > 0 || q->head == q->tail),
172  q->pre_event_timeout);
173 }
174 
175 /*
176  * drain one record
177  * caller must hold lock
178  */
179 void
181 {
182  if (q->qlen > 0) {
183  q->head = (q->head + 1) % q->maxlen;
184  q->qlen--;
185  }
186 }
187 
188 /*
189  * polling/select:
190  * return non-zero if readq is not empty.
191  */
192 unsigned int
194 {
195  poll_wait(file, &q->midi_sleep, wait);
196  return q->qlen;
197 }
198 
199 /*
200  * put a timestamp
201  */
202 int
203 snd_seq_oss_readq_put_timestamp(struct seq_oss_readq *q, unsigned long curt, int seq_mode)
204 {
205  if (curt != q->input_time) {
206  union evrec rec;
207  memset(&rec, 0, sizeof(rec));
208  switch (seq_mode) {
210  rec.echo = (curt << 8) | SEQ_WAIT;
212  break;
214  rec.t.code = EV_TIMING;
215  rec.t.cmd = TMR_WAIT_ABS;
216  rec.t.time = curt;
218  break;
219  }
220  q->input_time = curt;
221  }
222  return 0;
223 }
224 
225 
226 #ifdef CONFIG_PROC_FS
227 /*
228  * proc interface
229  */
230 void
232 {
233  snd_iprintf(buf, " read queue [%s] length = %d : tick = %ld\n",
234  (waitqueue_active(&q->midi_sleep) ? "sleeping":"running"),
235  q->qlen, q->input_time);
236 }
237 #endif /* CONFIG_PROC_FS */