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 */
24struct seq_oss_writeq *
25snd_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, arg: &pool);
46
47 return q;
48}
49
50/*
51 * delete the write queue
52 */
53void
54snd_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(objp: q);
59 }
60}
61
62
63/*
64 * reset the write queue
65 */
66void
67snd_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(dp: q->dp, SNDRV_SEQ_IOCTL_REMOVE_EVENTS, arg: &reset);
74
75 /* wake up sleepers if any */
76 snd_seq_oss_writeq_wakeup(q, time: 0);
77}
78
79/*
80 * wait until the write buffer has enough room
81 */
82int
83snd_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(timer: 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: &ev, dest_client: dp->addr.client, dest_port: 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(client: dp->cseq, ev: &ev, NULL, blocking: 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 */
122void
123snd_seq_oss_writeq_wakeup(struct seq_oss_writeq *q, abstime_t time)
124{
125 guard(spinlock_irqsave)(l: &q->sync_lock);
126 q->sync_time = time;
127 q->sync_event_put = 0;
128 wake_up(&q->sync_sleep);
129}
130
131
132/*
133 * return the unused pool size
134 */
135int
136snd_seq_oss_writeq_get_free_size(struct seq_oss_writeq *q)
137{
138 struct snd_seq_client_pool pool;
139 pool.client = q->dp->cseq;
140 snd_seq_oss_control(dp: q->dp, SNDRV_SEQ_IOCTL_GET_CLIENT_POOL, arg: &pool);
141 return pool.output_free;
142}
143
144
145/*
146 * set output threshold size from ioctl
147 */
148void
149snd_seq_oss_writeq_set_output(struct seq_oss_writeq *q, int val)
150{
151 struct snd_seq_client_pool pool;
152 pool.client = q->dp->cseq;
153 snd_seq_oss_control(dp: q->dp, SNDRV_SEQ_IOCTL_GET_CLIENT_POOL, arg: &pool);
154 pool.output_room = val;
155 snd_seq_oss_control(dp: q->dp, SNDRV_SEQ_IOCTL_SET_CLIENT_POOL, arg: &pool);
156}
157
158

source code of linux/sound/core/seq/oss/seq_oss_writeq.c