1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * OSS compatible sequencer driver
4  *
5  * seq_oss_writeq.c - write queue and sync
6  *
7  * Copyright (C) 1998,99 Takashi Iwai <tiwai@suse.de>
8  */
9 
10 #include "seq_oss_writeq.h"
11 #include "seq_oss_event.h"
12 #include "seq_oss_timer.h"
13 #include <sound/seq_oss_legacy.h>
14 #include "../seq_lock.h"
15 #include "../seq_clientmgr.h"
16 #include <linux/wait.h>
17 #include <linux/slab.h>
18 #include <linux/sched/signal.h>
19 
20 
21 /*
22  * create a write queue record
23  */
24 struct seq_oss_writeq *
25 snd_seq_oss_writeq_new(struct seq_oss_devinfo *dp, int maxlen)
26 {
27 	struct seq_oss_writeq *q;
28 	struct snd_seq_client_pool pool;
29 
30 	q = kzalloc(sizeof(*q), GFP_KERNEL);
31 	if (!q)
32 		return NULL;
33 	q->dp = dp;
34 	q->maxlen = maxlen;
35 	spin_lock_init(&q->sync_lock);
36 	q->sync_event_put = 0;
37 	q->sync_time = 0;
38 	init_waitqueue_head(&q->sync_sleep);
39 
40 	memset(&pool, 0, sizeof(pool));
41 	pool.client = dp->cseq;
42 	pool.output_pool = maxlen;
43 	pool.output_room = maxlen / 2;
44 
45 	snd_seq_oss_control(dp, SNDRV_SEQ_IOCTL_SET_CLIENT_POOL, &pool);
46 
47 	return q;
48 }
49 
50 /*
51  * delete the write queue
52  */
53 void
54 snd_seq_oss_writeq_delete(struct seq_oss_writeq *q)
55 {
56 	if (q) {
57 		snd_seq_oss_writeq_clear(q);	/* to be sure */
58 		kfree(q);
59 	}
60 }
61 
62 
63 /*
64  * reset the write queue
65  */
66 void
67 snd_seq_oss_writeq_clear(struct seq_oss_writeq *q)
68 {
69 	struct snd_seq_remove_events reset;
70 
71 	memset(&reset, 0, sizeof(reset));
72 	reset.remove_mode = SNDRV_SEQ_REMOVE_OUTPUT; /* remove all */
73 	snd_seq_oss_control(q->dp, SNDRV_SEQ_IOCTL_REMOVE_EVENTS, &reset);
74 
75 	/* wake up sleepers if any */
76 	snd_seq_oss_writeq_wakeup(q, 0);
77 }
78 
79 /*
80  * wait until the write buffer has enough room
81  */
82 int
83 snd_seq_oss_writeq_sync(struct seq_oss_writeq *q)
84 {
85 	struct seq_oss_devinfo *dp = q->dp;
86 	abstime_t time;
87 
88 	time = snd_seq_oss_timer_cur_tick(dp->timer);
89 	if (q->sync_time >= time)
90 		return 0; /* already finished */
91 
92 	if (! q->sync_event_put) {
93 		struct snd_seq_event ev;
94 		union evrec *rec;
95 
96 		/* put echoback event */
97 		memset(&ev, 0, sizeof(ev));
98 		ev.flags = 0;
99 		ev.type = SNDRV_SEQ_EVENT_ECHO;
100 		ev.time.tick = time;
101 		/* echo back to itself */
102 		snd_seq_oss_fill_addr(dp, &ev, dp->addr.client, dp->addr.port);
103 		rec = (union evrec *)&ev.data;
104 		rec->t.code = SEQ_SYNCTIMER;
105 		rec->t.time = time;
106 		q->sync_event_put = 1;
107 		snd_seq_kernel_client_enqueue(dp->cseq, &ev, NULL, true);
108 	}
109 
110 	wait_event_interruptible_timeout(q->sync_sleep, ! q->sync_event_put, HZ);
111 	if (signal_pending(current))
112 		/* interrupted - return 0 to finish sync */
113 		q->sync_event_put = 0;
114 	if (! q->sync_event_put || q->sync_time >= time)
115 		return 0;
116 	return 1;
117 }
118 
119 /*
120  * wake up sync - echo event was catched
121  */
122 void
123 snd_seq_oss_writeq_wakeup(struct seq_oss_writeq *q, abstime_t time)
124 {
125 	unsigned long flags;
126 
127 	spin_lock_irqsave(&q->sync_lock, flags);
128 	q->sync_time = time;
129 	q->sync_event_put = 0;
130 	wake_up(&q->sync_sleep);
131 	spin_unlock_irqrestore(&q->sync_lock, flags);
132 }
133 
134 
135 /*
136  * return the unused pool size
137  */
138 int
139 snd_seq_oss_writeq_get_free_size(struct seq_oss_writeq *q)
140 {
141 	struct snd_seq_client_pool pool;
142 	pool.client = q->dp->cseq;
143 	snd_seq_oss_control(q->dp, SNDRV_SEQ_IOCTL_GET_CLIENT_POOL, &pool);
144 	return pool.output_free;
145 }
146 
147 
148 /*
149  * set output threshold size from ioctl
150  */
151 void
152 snd_seq_oss_writeq_set_output(struct seq_oss_writeq *q, int val)
153 {
154 	struct snd_seq_client_pool pool;
155 	pool.client = q->dp->cseq;
156 	snd_seq_oss_control(q->dp, SNDRV_SEQ_IOCTL_GET_CLIENT_POOL, &pool);
157 	pool.output_room = val;
158 	snd_seq_oss_control(q->dp, SNDRV_SEQ_IOCTL_SET_CLIENT_POOL, &pool);
159 }
160 
161