1 /*
2 * ALSA sequencer FIFO
3 * Copyright (c) 1998 by Frank van de Pol <fvdpol@coil.demon.nl>
4 *
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
19 *
20 */
21
22 #include <sound/core.h>
23 #include <linux/slab.h>
24 #include "seq_fifo.h"
25 #include "seq_lock.h"
26
27
28 /* FIFO */
29
30 /* create new fifo */
31 struct snd_seq_fifo *snd_seq_fifo_new(int poolsize)
32 {
33 struct snd_seq_fifo *f;
34
35 f = kzalloc(sizeof(*f), GFP_KERNEL);
36 if (f == NULL) {
37 snd_printd("malloc failed for snd_seq_fifo_new() \n");
38 return NULL;
39 }
40
41 f->pool = snd_seq_pool_new(poolsize);
42 if (f->pool == NULL) {
43 kfree(f);
44 return NULL;
45 }
46 if (snd_seq_pool_init(f->pool) < 0) {
47 snd_seq_pool_delete(&f->pool);
48 kfree(f);
49 return NULL;
50 }
51
52 spin_lock_init(&f->lock);
53 snd_use_lock_init(&f->use_lock);
54 init_waitqueue_head(&f->input_sleep);
55 atomic_set(&f->overflow, 0);
56
57 f->head = NULL;
58 f->tail = NULL;
59 f->cells = 0;
60
61 return f;
62 }
63
64 void snd_seq_fifo_delete(struct snd_seq_fifo **fifo)
65 {
66 struct snd_seq_fifo *f;
67
68 snd_assert(fifo != NULL, return);
69 f = *fifo;
70 snd_assert(f != NULL, return);
71 *fifo = NULL;
72
73 snd_seq_fifo_clear(f);
74
75 /* wake up clients if any */
76 if (waitqueue_active(&f->input_sleep))
77 wake_up(&f->input_sleep);
78
79 /* release resources...*/
80 /*....................*/
81
82 if (f->pool) {
83 snd_seq_pool_done(f->pool);
84 snd_seq_pool_delete(&f->pool);
85 }
86
87 kfree(f);
88 }
89
90 static struct snd_seq_event_cell *fifo_cell_out(struct snd_seq_fifo *f);
91
92 /* clear queue */
93 void snd_seq_fifo_clear(struct snd_seq_fifo *f)
94 {
95 struct snd_seq_event_cell *cell;
96 unsigned long flags;
97
98 /* clear overflow flag */
99 atomic_set(&f->overflow, 0);
100
101 snd_use_lock_sync(&f->use_lock);
102 spin_lock_irqsave(&f->lock, flags);
103 /* drain the fifo */
104 while ((cell = fifo_cell_out(f)) != NULL) {
105 snd_seq_cell_free(cell);
106 }
107 spin_unlock_irqrestore(&f->lock, flags);
108 }
109
110
111 /* enqueue event to fifo */
112 int snd_seq_fifo_event_in(struct snd_seq_fifo *f,
113 struct snd_seq_event *event)
114 {
115 struct snd_seq_event_cell *cell;
116 unsigned long flags;
117 int err;
118
119 snd_assert(f != NULL, return -EINVAL);
120
121 snd_use_lock_use(&f->use_lock);
122 err = snd_seq_event_dup(f->pool, event, &cell, 1, NULL); /* always non-blocking */
123 if (err < 0) {
124 if (err == -ENOMEM)
125 atomic_inc(&f->overflow);
126 snd_use_lock_free(&f->use_lock);
127 return err;
128 }
129
130 /* append new cells to fifo */
131 spin_lock_irqsave(&f->lock, flags);
132 if (f->tail != NULL)
133 f->tail->next = cell;
134 f->tail = cell;
135 if (f->head == NULL)
136 f->head = cell;
137 f->cells++;
138 spin_unlock_irqrestore(&f->lock, flags);
139
140 /* wakeup client */
141 if (waitqueue_active(&f->input_sleep))
142 wake_up(&f->input_sleep);
143
144 snd_use_lock_free(&f->use_lock);
145
146 return 0; /* success */
147
148 }
149
150 /* dequeue cell from fifo */
151 static struct snd_seq_event_cell *fifo_cell_out(struct snd_seq_fifo *f)
152 {
153 struct snd_seq_event_cell *cell;
154
155 if ((cell = f->head) != NULL) {
156 f->head = cell->next;
157
158 /* reset tail if this was the last element */
159 if (f->tail == cell)
160 f->tail = NULL;
161
162 cell->next = NULL;
163 f->cells--;
164 }
165
166 return cell;
167 }
168
169 /* dequeue cell from fifo and copy on user space */
170 int snd_seq_fifo_cell_out(struct snd_seq_fifo *f,
171 struct snd_seq_event_cell **cellp, int nonblock)
172 {
173 struct snd_seq_event_cell *cell;
174 unsigned long flags;
175 wait_queue_t wait;
176
177 snd_assert(f != NULL, return -EINVAL);
178
179 *cellp = NULL;
180 init_waitqueue_entry(&wait, current);
181 spin_lock_irqsave(&f->lock, flags);
182 while ((cell = fifo_cell_out(f)) == NULL) {
183 if (nonblock) {
184 /* non-blocking - return immediately */
185 spin_unlock_irqrestore(&f->lock, flags);
186 return -EAGAIN;
187 }
188 set_current_state(TASK_INTERRUPTIBLE);
189 add_wait_queue(&f->input_sleep, &wait);
190 spin_unlock_irq(&f->lock);
191 schedule();
192 spin_lock_irq(&f->lock);
193 remove_wait_queue(&f->input_sleep, &wait);
194 if (signal_pending(current)) {
195 spin_unlock_irqrestore(&f->lock, flags);
196 return -ERESTARTSYS;
197 }
198 }
199 spin_unlock_irqrestore(&f->lock, flags);
200 *cellp = cell;
201
202 return 0;
203 }
204
205
206 void snd_seq_fifo_cell_putback(struct snd_seq_fifo *f,
207 struct snd_seq_event_cell *cell)
208 {
209 unsigned long flags;
210
211 if (cell) {
212 spin_lock_irqsave(&f->lock, flags);
213 cell->next = f->head;
214 f->head = cell;
215 f->cells++;
216 spin_unlock_irqrestore(&f->lock, flags);
217 }
218 }
219
220
221 /* polling; return non-zero if queue is available */
222 int snd_seq_fifo_poll_wait(struct snd_seq_fifo *f, struct file *file,
223 poll_table *wait)
224 {
225 poll_wait(file, &f->input_sleep, wait);
226 return (f->cells > 0);
227 }
228
229 /* change the size of pool; all old events are removed */
230 int snd_seq_fifo_resize(struct snd_seq_fifo *f, int poolsize)
231 {
232 unsigned long flags;
233 struct snd_seq_pool *newpool, *oldpool;
234 struct snd_seq_event_cell *cell, *next, *oldhead;
235
236 snd_assert(f != NULL && f->pool != NULL, return -EINVAL);
237
238 /* allocate new pool */
239 newpool = snd_seq_pool_new(poolsize);
240 if (newpool == NULL)
241 return -ENOMEM;
242 if (snd_seq_pool_init(newpool) < 0) {
243 snd_seq_pool_delete(&newpool);
244 return -ENOMEM;
245 }
246
247 spin_lock_irqsave(&f->lock, flags);
248 /* remember old pool */
249 oldpool = f->pool;
250 oldhead = f->head;
251 /* exchange pools */
252 f->pool = newpool;
253 f->head = NULL;
254 f->tail = NULL;
255 f->cells = 0;
256 /* NOTE: overflow flag is not cleared */
257 spin_unlock_irqrestore(&f->lock, flags);
258
259 /* release cells in old pool */
260 for (cell = oldhead; cell; cell = next) {
261 next = cell->next;
262 snd_seq_cell_free(cell);
263 }
264 snd_seq_pool_delete(&oldpool);
265
266 return 0;
267 }
268
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