Merge branch 'iommu-fixes-2.6.28' of git://git.kernel.org/pub/scm/linux/kernel/git...
[linux-2.6] / sound / core / seq / seq_fifo.c
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         if (snd_BUG_ON(!fifo))
69                 return;
70         f = *fifo;
71         if (snd_BUG_ON(!f))
72                 return;
73         *fifo = NULL;
74
75         snd_seq_fifo_clear(f);
76
77         /* wake up clients if any */
78         if (waitqueue_active(&f->input_sleep))
79                 wake_up(&f->input_sleep);
80
81         /* release resources...*/
82         /*....................*/
83
84         if (f->pool) {
85                 snd_seq_pool_done(f->pool);
86                 snd_seq_pool_delete(&f->pool);
87         }
88         
89         kfree(f);
90 }
91
92 static struct snd_seq_event_cell *fifo_cell_out(struct snd_seq_fifo *f);
93
94 /* clear queue */
95 void snd_seq_fifo_clear(struct snd_seq_fifo *f)
96 {
97         struct snd_seq_event_cell *cell;
98         unsigned long flags;
99
100         /* clear overflow flag */
101         atomic_set(&f->overflow, 0);
102
103         snd_use_lock_sync(&f->use_lock);
104         spin_lock_irqsave(&f->lock, flags);
105         /* drain the fifo */
106         while ((cell = fifo_cell_out(f)) != NULL) {
107                 snd_seq_cell_free(cell);
108         }
109         spin_unlock_irqrestore(&f->lock, flags);
110 }
111
112
113 /* enqueue event to fifo */
114 int snd_seq_fifo_event_in(struct snd_seq_fifo *f,
115                           struct snd_seq_event *event)
116 {
117         struct snd_seq_event_cell *cell;
118         unsigned long flags;
119         int err;
120
121         if (snd_BUG_ON(!f))
122                 return -EINVAL;
123
124         snd_use_lock_use(&f->use_lock);
125         err = snd_seq_event_dup(f->pool, event, &cell, 1, NULL); /* always non-blocking */
126         if (err < 0) {
127                 if (err == -ENOMEM)
128                         atomic_inc(&f->overflow);
129                 snd_use_lock_free(&f->use_lock);
130                 return err;
131         }
132                 
133         /* append new cells to fifo */
134         spin_lock_irqsave(&f->lock, flags);
135         if (f->tail != NULL)
136                 f->tail->next = cell;
137         f->tail = cell;
138         if (f->head == NULL)
139                 f->head = cell;
140         f->cells++;
141         spin_unlock_irqrestore(&f->lock, flags);
142
143         /* wakeup client */
144         if (waitqueue_active(&f->input_sleep))
145                 wake_up(&f->input_sleep);
146
147         snd_use_lock_free(&f->use_lock);
148
149         return 0; /* success */
150
151 }
152
153 /* dequeue cell from fifo */
154 static struct snd_seq_event_cell *fifo_cell_out(struct snd_seq_fifo *f)
155 {
156         struct snd_seq_event_cell *cell;
157
158         if ((cell = f->head) != NULL) {
159                 f->head = cell->next;
160
161                 /* reset tail if this was the last element */
162                 if (f->tail == cell)
163                         f->tail = NULL;
164
165                 cell->next = NULL;
166                 f->cells--;
167         }
168
169         return cell;
170 }
171
172 /* dequeue cell from fifo and copy on user space */
173 int snd_seq_fifo_cell_out(struct snd_seq_fifo *f,
174                           struct snd_seq_event_cell **cellp, int nonblock)
175 {
176         struct snd_seq_event_cell *cell;
177         unsigned long flags;
178         wait_queue_t wait;
179
180         if (snd_BUG_ON(!f))
181                 return -EINVAL;
182
183         *cellp = NULL;
184         init_waitqueue_entry(&wait, current);
185         spin_lock_irqsave(&f->lock, flags);
186         while ((cell = fifo_cell_out(f)) == NULL) {
187                 if (nonblock) {
188                         /* non-blocking - return immediately */
189                         spin_unlock_irqrestore(&f->lock, flags);
190                         return -EAGAIN;
191                 }
192                 set_current_state(TASK_INTERRUPTIBLE);
193                 add_wait_queue(&f->input_sleep, &wait);
194                 spin_unlock_irq(&f->lock);
195                 schedule();
196                 spin_lock_irq(&f->lock);
197                 remove_wait_queue(&f->input_sleep, &wait);
198                 if (signal_pending(current)) {
199                         spin_unlock_irqrestore(&f->lock, flags);
200                         return -ERESTARTSYS;
201                 }
202         }
203         spin_unlock_irqrestore(&f->lock, flags);
204         *cellp = cell;
205
206         return 0;
207 }
208
209
210 void snd_seq_fifo_cell_putback(struct snd_seq_fifo *f,
211                                struct snd_seq_event_cell *cell)
212 {
213         unsigned long flags;
214
215         if (cell) {
216                 spin_lock_irqsave(&f->lock, flags);
217                 cell->next = f->head;
218                 f->head = cell;
219                 f->cells++;
220                 spin_unlock_irqrestore(&f->lock, flags);
221         }
222 }
223
224
225 /* polling; return non-zero if queue is available */
226 int snd_seq_fifo_poll_wait(struct snd_seq_fifo *f, struct file *file,
227                            poll_table *wait)
228 {
229         poll_wait(file, &f->input_sleep, wait);
230         return (f->cells > 0);
231 }
232
233 /* change the size of pool; all old events are removed */
234 int snd_seq_fifo_resize(struct snd_seq_fifo *f, int poolsize)
235 {
236         unsigned long flags;
237         struct snd_seq_pool *newpool, *oldpool;
238         struct snd_seq_event_cell *cell, *next, *oldhead;
239
240         if (snd_BUG_ON(!f || !f->pool))
241                 return -EINVAL;
242
243         /* allocate new pool */
244         newpool = snd_seq_pool_new(poolsize);
245         if (newpool == NULL)
246                 return -ENOMEM;
247         if (snd_seq_pool_init(newpool) < 0) {
248                 snd_seq_pool_delete(&newpool);
249                 return -ENOMEM;
250         }
251
252         spin_lock_irqsave(&f->lock, flags);
253         /* remember old pool */
254         oldpool = f->pool;
255         oldhead = f->head;
256         /* exchange pools */
257         f->pool = newpool;
258         f->head = NULL;
259         f->tail = NULL;
260         f->cells = 0;
261         /* NOTE: overflow flag is not cleared */
262         spin_unlock_irqrestore(&f->lock, flags);
263
264         /* release cells in old pool */
265         for (cell = oldhead; cell; cell = next) {
266                 next = cell->next;
267                 snd_seq_cell_free(cell);
268         }
269         snd_seq_pool_delete(&oldpool);
270
271         return 0;
272 }