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