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/driver.h> 23 #include <sound/core.h> 24 #include <linux/slab.h> 25 #include "seq_fifo.h" 26 #include "seq_lock.h" 27 28 29 /* FIFO */ 30 31 /* create new fifo */ 32 fifo_t *snd_seq_fifo_new(int poolsize) 33 { 34 fifo_t *f; 35 36 f = kzalloc(sizeof(*f), GFP_KERNEL); 37 if (f == NULL) { 38 snd_printd("malloc failed for snd_seq_fifo_new() \n"); 39 return NULL; 40 } 41 42 f->pool = snd_seq_pool_new(poolsize); 43 if (f->pool == NULL) { 44 kfree(f); 45 return NULL; 46 } 47 if (snd_seq_pool_init(f->pool) < 0) { 48 snd_seq_pool_delete(&f->pool); 49 kfree(f); 50 return NULL; 51 } 52 53 spin_lock_init(&f->lock); 54 snd_use_lock_init(&f->use_lock); 55 init_waitqueue_head(&f->input_sleep); 56 atomic_set(&f->overflow, 0); 57 58 f->head = NULL; 59 f->tail = NULL; 60 f->cells = 0; 61 62 return f; 63 } 64 65 void snd_seq_fifo_delete(fifo_t **fifo) 66 { 67 fifo_t *f; 68 69 snd_assert(fifo != NULL, return); 70 f = *fifo; 71 snd_assert(f != NULL, return); 72 *fifo = NULL; 73 74 snd_seq_fifo_clear(f); 75 76 /* wake up clients if any */ 77 if (waitqueue_active(&f->input_sleep)) 78 wake_up(&f->input_sleep); 79 80 /* release resources...*/ 81 /*....................*/ 82 83 if (f->pool) { 84 snd_seq_pool_done(f->pool); 85 snd_seq_pool_delete(&f->pool); 86 } 87 88 kfree(f); 89 } 90 91 static snd_seq_event_cell_t *fifo_cell_out(fifo_t *f); 92 93 /* clear queue */ 94 void snd_seq_fifo_clear(fifo_t *f) 95 { 96 snd_seq_event_cell_t *cell; 97 unsigned long flags; 98 99 /* clear overflow flag */ 100 atomic_set(&f->overflow, 0); 101 102 snd_use_lock_sync(&f->use_lock); 103 spin_lock_irqsave(&f->lock, flags); 104 /* drain the fifo */ 105 while ((cell = fifo_cell_out(f)) != NULL) { 106 snd_seq_cell_free(cell); 107 } 108 spin_unlock_irqrestore(&f->lock, flags); 109 } 110 111 112 /* enqueue event to fifo */ 113 int snd_seq_fifo_event_in(fifo_t *f, snd_seq_event_t *event) 114 { 115 snd_seq_event_cell_t *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 snd_seq_event_cell_t *fifo_cell_out(fifo_t *f) 152 { 153 snd_seq_event_cell_t *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(fifo_t *f, snd_seq_event_cell_t **cellp, int nonblock) 171 { 172 snd_seq_event_cell_t *cell; 173 unsigned long flags; 174 wait_queue_t wait; 175 176 snd_assert(f != NULL, return -EINVAL); 177 178 *cellp = NULL; 179 init_waitqueue_entry(&wait, current); 180 spin_lock_irqsave(&f->lock, flags); 181 while ((cell = fifo_cell_out(f)) == NULL) { 182 if (nonblock) { 183 /* non-blocking - return immediately */ 184 spin_unlock_irqrestore(&f->lock, flags); 185 return -EAGAIN; 186 } 187 set_current_state(TASK_INTERRUPTIBLE); 188 add_wait_queue(&f->input_sleep, &wait); 189 spin_unlock_irq(&f->lock); 190 schedule(); 191 spin_lock_irq(&f->lock); 192 remove_wait_queue(&f->input_sleep, &wait); 193 if (signal_pending(current)) { 194 spin_unlock_irqrestore(&f->lock, flags); 195 return -ERESTARTSYS; 196 } 197 } 198 spin_unlock_irqrestore(&f->lock, flags); 199 *cellp = cell; 200 201 return 0; 202 } 203 204 205 void snd_seq_fifo_cell_putback(fifo_t *f, snd_seq_event_cell_t *cell) 206 { 207 unsigned long flags; 208 209 if (cell) { 210 spin_lock_irqsave(&f->lock, flags); 211 cell->next = f->head; 212 f->head = cell; 213 f->cells++; 214 spin_unlock_irqrestore(&f->lock, flags); 215 } 216 } 217 218 219 /* polling; return non-zero if queue is available */ 220 int snd_seq_fifo_poll_wait(fifo_t *f, struct file *file, poll_table *wait) 221 { 222 poll_wait(file, &f->input_sleep, wait); 223 return (f->cells > 0); 224 } 225 226 /* change the size of pool; all old events are removed */ 227 int snd_seq_fifo_resize(fifo_t *f, int poolsize) 228 { 229 unsigned long flags; 230 pool_t *newpool, *oldpool; 231 snd_seq_event_cell_t *cell, *next, *oldhead; 232 233 snd_assert(f != NULL && f->pool != NULL, return -EINVAL); 234 235 /* allocate new pool */ 236 newpool = snd_seq_pool_new(poolsize); 237 if (newpool == NULL) 238 return -ENOMEM; 239 if (snd_seq_pool_init(newpool) < 0) { 240 snd_seq_pool_delete(&newpool); 241 return -ENOMEM; 242 } 243 244 spin_lock_irqsave(&f->lock, flags); 245 /* remember old pool */ 246 oldpool = f->pool; 247 oldhead = f->head; 248 /* exchange pools */ 249 f->pool = newpool; 250 f->head = NULL; 251 f->tail = NULL; 252 f->cells = 0; 253 /* NOTE: overflow flag is not cleared */ 254 spin_unlock_irqrestore(&f->lock, flags); 255 256 /* release cells in old pool */ 257 for (cell = oldhead; cell; cell = next) { 258 next = cell->next; 259 snd_seq_cell_free(cell); 260 } 261 snd_seq_pool_delete(&oldpool); 262 263 return 0; 264 } 265