1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * OSS compatible sequencer driver
4 *
5 * seq_oss_readq.c - MIDI input queue
6 *
7 * Copyright (C) 1998,99 Takashi Iwai <tiwai@suse.de>
8 */
9
10 #include "seq_oss_readq.h"
11 #include "seq_oss_event.h"
12 #include <sound/seq_oss_legacy.h>
13 #include "../seq_lock.h"
14 #include <linux/wait.h>
15 #include <linux/slab.h>
16
17 /*
18 * constants
19 */
20 //#define SNDRV_SEQ_OSS_MAX_TIMEOUT (unsigned long)(-1)
21 #define SNDRV_SEQ_OSS_MAX_TIMEOUT (HZ * 3600)
22
23
24 /*
25 * prototypes
26 */
27
28
29 /*
30 * create a read queue
31 */
32 struct seq_oss_readq *
snd_seq_oss_readq_new(struct seq_oss_devinfo * dp,int maxlen)33 snd_seq_oss_readq_new(struct seq_oss_devinfo *dp, int maxlen)
34 {
35 struct seq_oss_readq *q;
36
37 q = kzalloc(sizeof(*q), GFP_KERNEL);
38 if (!q)
39 return NULL;
40
41 q->q = kcalloc(maxlen, sizeof(union evrec), GFP_KERNEL);
42 if (!q->q) {
43 kfree(q);
44 return NULL;
45 }
46
47 q->maxlen = maxlen;
48 q->qlen = 0;
49 q->head = q->tail = 0;
50 init_waitqueue_head(&q->midi_sleep);
51 spin_lock_init(&q->lock);
52 q->pre_event_timeout = SNDRV_SEQ_OSS_MAX_TIMEOUT;
53 q->input_time = (unsigned long)-1;
54
55 return q;
56 }
57
58 /*
59 * delete the read queue
60 */
61 void
snd_seq_oss_readq_delete(struct seq_oss_readq * q)62 snd_seq_oss_readq_delete(struct seq_oss_readq *q)
63 {
64 if (q) {
65 kfree(q->q);
66 kfree(q);
67 }
68 }
69
70 /*
71 * reset the read queue
72 */
73 void
snd_seq_oss_readq_clear(struct seq_oss_readq * q)74 snd_seq_oss_readq_clear(struct seq_oss_readq *q)
75 {
76 if (q->qlen) {
77 q->qlen = 0;
78 q->head = q->tail = 0;
79 }
80 /* if someone sleeping, wake'em up */
81 wake_up(&q->midi_sleep);
82 q->input_time = (unsigned long)-1;
83 }
84
85 /*
86 * put a midi byte
87 */
88 int
snd_seq_oss_readq_puts(struct seq_oss_readq * q,int dev,unsigned char * data,int len)89 snd_seq_oss_readq_puts(struct seq_oss_readq *q, int dev, unsigned char *data, int len)
90 {
91 union evrec rec;
92 int result;
93
94 memset(&rec, 0, sizeof(rec));
95 rec.c[0] = SEQ_MIDIPUTC;
96 rec.c[2] = dev;
97
98 while (len-- > 0) {
99 rec.c[1] = *data++;
100 result = snd_seq_oss_readq_put_event(q, &rec);
101 if (result < 0)
102 return result;
103 }
104 return 0;
105 }
106
107 /*
108 * put MIDI sysex bytes; the event buffer may be chained, thus it has
109 * to be expanded via snd_seq_dump_var_event().
110 */
111 struct readq_sysex_ctx {
112 struct seq_oss_readq *readq;
113 int dev;
114 };
115
readq_dump_sysex(void * ptr,void * buf,int count)116 static int readq_dump_sysex(void *ptr, void *buf, int count)
117 {
118 struct readq_sysex_ctx *ctx = ptr;
119
120 return snd_seq_oss_readq_puts(ctx->readq, ctx->dev, buf, count);
121 }
122
snd_seq_oss_readq_sysex(struct seq_oss_readq * q,int dev,struct snd_seq_event * ev)123 int snd_seq_oss_readq_sysex(struct seq_oss_readq *q, int dev,
124 struct snd_seq_event *ev)
125 {
126 struct readq_sysex_ctx ctx = {
127 .readq = q,
128 .dev = dev
129 };
130
131 if ((ev->flags & SNDRV_SEQ_EVENT_LENGTH_MASK) != SNDRV_SEQ_EVENT_LENGTH_VARIABLE)
132 return 0;
133 return snd_seq_dump_var_event(ev, readq_dump_sysex, &ctx);
134 }
135
136 /*
137 * copy an event to input queue:
138 * return zero if enqueued
139 */
140 int
snd_seq_oss_readq_put_event(struct seq_oss_readq * q,union evrec * ev)141 snd_seq_oss_readq_put_event(struct seq_oss_readq *q, union evrec *ev)
142 {
143 unsigned long flags;
144
145 spin_lock_irqsave(&q->lock, flags);
146 if (q->qlen >= q->maxlen - 1) {
147 spin_unlock_irqrestore(&q->lock, flags);
148 return -ENOMEM;
149 }
150
151 memcpy(&q->q[q->tail], ev, sizeof(*ev));
152 q->tail = (q->tail + 1) % q->maxlen;
153 q->qlen++;
154
155 /* wake up sleeper */
156 wake_up(&q->midi_sleep);
157
158 spin_unlock_irqrestore(&q->lock, flags);
159
160 return 0;
161 }
162
163
164 /*
165 * pop queue
166 * caller must hold lock
167 */
168 int
snd_seq_oss_readq_pick(struct seq_oss_readq * q,union evrec * rec)169 snd_seq_oss_readq_pick(struct seq_oss_readq *q, union evrec *rec)
170 {
171 if (q->qlen == 0)
172 return -EAGAIN;
173 memcpy(rec, &q->q[q->head], sizeof(*rec));
174 return 0;
175 }
176
177 /*
178 * sleep until ready
179 */
180 void
snd_seq_oss_readq_wait(struct seq_oss_readq * q)181 snd_seq_oss_readq_wait(struct seq_oss_readq *q)
182 {
183 wait_event_interruptible_timeout(q->midi_sleep,
184 (q->qlen > 0 || q->head == q->tail),
185 q->pre_event_timeout);
186 }
187
188 /*
189 * drain one record
190 * caller must hold lock
191 */
192 void
snd_seq_oss_readq_free(struct seq_oss_readq * q)193 snd_seq_oss_readq_free(struct seq_oss_readq *q)
194 {
195 if (q->qlen > 0) {
196 q->head = (q->head + 1) % q->maxlen;
197 q->qlen--;
198 }
199 }
200
201 /*
202 * polling/select:
203 * return non-zero if readq is not empty.
204 */
205 unsigned int
snd_seq_oss_readq_poll(struct seq_oss_readq * q,struct file * file,poll_table * wait)206 snd_seq_oss_readq_poll(struct seq_oss_readq *q, struct file *file, poll_table *wait)
207 {
208 poll_wait(file, &q->midi_sleep, wait);
209 return q->qlen;
210 }
211
212 /*
213 * put a timestamp
214 */
215 int
snd_seq_oss_readq_put_timestamp(struct seq_oss_readq * q,unsigned long curt,int seq_mode)216 snd_seq_oss_readq_put_timestamp(struct seq_oss_readq *q, unsigned long curt, int seq_mode)
217 {
218 if (curt != q->input_time) {
219 union evrec rec;
220 memset(&rec, 0, sizeof(rec));
221 switch (seq_mode) {
222 case SNDRV_SEQ_OSS_MODE_SYNTH:
223 rec.echo = (curt << 8) | SEQ_WAIT;
224 snd_seq_oss_readq_put_event(q, &rec);
225 break;
226 case SNDRV_SEQ_OSS_MODE_MUSIC:
227 rec.t.code = EV_TIMING;
228 rec.t.cmd = TMR_WAIT_ABS;
229 rec.t.time = curt;
230 snd_seq_oss_readq_put_event(q, &rec);
231 break;
232 }
233 q->input_time = curt;
234 }
235 return 0;
236 }
237
238
239 #ifdef CONFIG_SND_PROC_FS
240 /*
241 * proc interface
242 */
243 void
snd_seq_oss_readq_info_read(struct seq_oss_readq * q,struct snd_info_buffer * buf)244 snd_seq_oss_readq_info_read(struct seq_oss_readq *q, struct snd_info_buffer *buf)
245 {
246 snd_iprintf(buf, " read queue [%s] length = %d : tick = %ld\n",
247 (waitqueue_active(&q->midi_sleep) ? "sleeping":"running"),
248 q->qlen, q->input_time);
249 }
250 #endif /* CONFIG_SND_PROC_FS */
251